IconForge: rust-g Spritesheet Generation (#89478)

## About The Pull Request

Replaces the asset subsystem's spritesheet generator with a rust-based
implementation (https://github.com/tgstation/rust-g/pull/160).

This is a rough port of
https://github.com/BeeStation/BeeStation-Hornet/pull/10404, but it
includes fixes for some cases I didn't catch that apply on TG.

(FWIW we've been using this system on prod for over a year and
encountered no major issues.)

### TG MAINTAINER NOTE


![image](https://github.com/user-attachments/assets/53bd2b44-9bb5-42d2-b33f-093651edebc0)

### Batched Spritesheets

`/datum/asset/spritesheet_batched`: A version of the spritesheet system
that collects a list of `/datum/universal_icon`s and sends them off to
rustg asynchronously, and the generation also runs on another thread, so
the game doesn't block during realize_spritesheet. The rust generation
is about 10x faster when it comes to actual icon generation, but the
biggest perk of the batched spritesheets is the caching system.

This PR notably does not convert a few things to the new spritesheet
generator.

- Species and antagonist icons in the preferences view because they use
getFlatIcon ~~which can't be converted to universal icons~~.
- Yes, this is still a *massive* cost to init, unfortunately. On Bee, I
actually enabled the 'legacy' cache on prod and development, which you
can see in my PR. That's why I added the 'clear cache' verb and the
`unregister()` procs, because it can force a regeneration at runtime. I
decided not to port this, since I think it would be detrimental to the
large amount of contributors here.
- It is *technically* possible to port parts of this to the uni_icon
system by making a uni_icon version of getFlatIcon. However, some
overlays use runtime-generated icons which are ~~completely unparseable
to IconForge, since they're stored in the RSC and don't exist as files
anywhere~~. This is most noticeable with things like hair (which blend
additively with the hair mask on the server, thus making them invisible
to `get_flat_uni_icon`). It also doesn't help that species and antag
icons will still need to generate a bunch of dummies and delete them to
even verify cache validity.
- It is actually possible to write the RSC icons to the filesystem
(using fcopy) and reference them in IconForge. However, I'm going to
wait on doing this until I port my GAGS implementation because it
requires GAGS to exist on the filesystem as well.

#### Caching

IconForge generates a cache based on the set of icons used, all
transform operations applied, and the source DMIs of each icon used
within the spritesheet. It can compare the hashes and invalidate the
cache automatically if any of these change. This means we can enable
caching on development, and have absolutely no downsides, because if
anything changes, the cache invalidates itself.

The caching has a mean cost of ~5ms and saves a lot of time compared to
generating the spritesheet, even with rust's faster generation. The main
downside is that the cache still requires building the list of icons and
their transforms, then json encoding it to send to rustg.

Here's an abbreviated example of a cache JSON. All of these need to
match for the cache to be valid. `input_hash` contains the transform
definitions for all the sprites in the spritesheet, so if the input to
iconforge changes, that hash catches it. The `sizes` and `sprites` are
loaded into DM.

```json
{
	"input_hash": "99f1bc67d590e000",
	"dmi_hashes": {
		"icons/ui/achievements/achievements.dmi": "771200c75da11c62"
	},
	"sizes": [
		"76x76"
	],
	"sprites": {
		"achievement-rustascend": {
			"size_id": "76x76",
			"position": 1
		}
	},
	"rustg_version": "3.6.0",
	"dm_version": 1
}
```

### Universal Icons

Universal icons are just a collection of DMI, Icon State, and any icon
transformation procs you apply (blends, crops, scales). They can be
convered to DM icons via `to_icon()`. I've included an implementation of
GAGS that produces universal icons, allowing GAGS items to be converted
into them. IconForge can read universal icons and add them to
spritesheets. It's basically just a wrapper that reimplements BYOND icon
procs.

### Other Stuff

Converts some uses of md5asfile within legacy spritesheets to use
rustg_hash_file instead, improving the performance of their generation.

Fixes lizard body markings not showing in previews, and re-adds eyes to
the ethereal color preview. This is a side effect of IconForge having
*much* better error handling than DM icon procs. Invalid stuff that gets
passed around will error instead of silently doing nothing.

Changes the CSS used in legacy spritesheet generation to split
`background: url(...) no-repeat` into separate props. This is necessary
for WebView2, as IE treats these properties differently - adding
`background-color` to an icon object (as seen in the R&D console) won't
work if you don't split these out.

Deletes unused spritesheets and their associated icons (condiments
spritesheet, old PDA spritesheet)

## Why It's Good For The Game

If you press "Character Setup", the 10-13sec of lag is now approximately
0.5-2 seconds.

Tracy profile showing the time spent on get_asset_datum. I pressed the
preferences button during init on both branches. Do note that this was
ran with a smart cache HIT, so no generation occurred.


![image](https://github.com/user-attachments/assets/3efa71ab-972b-4f5a-acab-0892496ef999)

Much lower worst-case for /datum/asset/New (which includes
`create_spritesheets()` and `register()`)


![image](https://github.com/user-attachments/assets/9ad8ceee-7bd6-4c48-b5f3-006520f527ef)

Here's a look at the internal costs from rustg - as you can see
`generate_spritesheet()` is very fast:


![image](https://github.com/user-attachments/assets/e6892c28-8c31-4af5-96d4-501e966d0ce9)

### Comparison for a single spritesheet - chat spritesheet:

**Before**


![image](https://github.com/user-attachments/assets/cbd65787-42ba-4278-a45c-bd3d538da986)

**After**


![image](https://github.com/user-attachments/assets/d750899a-bd07-4b57-80fb-420fcc0ae416)

## Changelog

🆑
fix: Fixed lizard body markings and ethereal feature previews in the
preference menu missing some overlays.
refactor: Optimized spritesheet asset generation greatly using rustg
IconForge, greatly reducing post-initialization lag as well as reducing
init times and saving server computation.
config: Added 'smart' asset caching, for batched rustg IconForge
spritesheets. It is persistent and suitable for use on local, with
automatic invalidation.
add: Added admin verbs - Debug -> Clear Smart/Legacy Asset Cache for
spritesheets.
fix: Fixed R&D console icons breaking on WebView2/516
/🆑

code/__DEFINES/assets.dm

@@ -0,0 +1,16 @@
+#define ASSET_CROSS_ROUND_CACHE_DIRECTORY "cache/assets"
+#define ASSET_CROSS_ROUND_SMART_CACHE_DIRECTORY "data/spritesheets/smart_cache"
+
+/// When sending mutiple assets, how many before we give the client a quaint little sending resources message
+#define ASSET_CACHE_TELL_CLIENT_AMOUNT 8
+
+/// How many assets can be sent at once during legacy asset transport
+#define SLOW_ASSET_SEND_RATE 6
+
+/// Constructs a universal icon. This is done in the same manner as the icon() BYOND proc.
+/// "color" will not do anything if a transform is provided. Blend it yourself or use color_transform().
+/// Do note that transforms are NOT COPIED, and are internally lists. So take care not to re-use transforms.
+/// This is a DEFINE for performance reasons.
+/// Parameters (in order):
+/// icon_file, icon_state, dir, frame, transform, color
+#define uni_icon(I, icon_state, rest...) new /datum/universal_icon(I, icon_state, ##rest)

code/__HELPERS/_lists.dm

@@ -845,6 +845,21 @@
 			.[i] = key
 			.[key] = value
 
+/// A version of deep_copy_list that actually supports associative list nesting: list(list(list("a" = "b"))) will actually copy correctly.
+/proc/deep_copy_list_alt(list/inserted_list)
+	if(!islist(inserted_list))
+		return inserted_list
+	var/copied_list = inserted_list.Copy()
+	. = copied_list
+	for(var/key_or_value in inserted_list)
+		if(isnum(key_or_value) || !inserted_list[key_or_value])
+			continue
+		var/value = inserted_list[key_or_value]
+		var/new_value = value
+		if(islist(value))
+			new_value = deep_copy_list_alt(value)
+		copied_list[key_or_value] = new_value
+
 ///takes an input_key, as text, and the list of keys already used, outputting a replacement key in the format of "[input_key] ([number_of_duplicates])" if it finds a duplicate
 ///use this for lists of things that might have the same name, like mobs or objects, that you plan on giving to a player as input
 /proc/avoid_assoc_duplicate_keys(input_key, list/used_key_list)

code/__HELPERS/files.dm

@@ -111,6 +111,7 @@ GLOBAL_VAR_INIT(fileaccess_timer, 0)
 
 /// Save file as an external file then md5 it.
 /// Used because md5ing files stored in the rsc sometimes gives incorrect md5 results.
+/// https://www.byond.com/forum/post/2611357
 /proc/md5asfile(file)
 	var/static/notch = 0
 	// its importaint this code can handle md5filepath sleeping instead of hard blocking, if it's converted to use rust_g.

code/controllers/configuration/entries/general.dm

@@ -704,6 +704,9 @@
 /datum/config_entry/flag/cache_assets
 	default = TRUE
 
+/datum/config_entry/flag/smart_cache_assets
+	default = TRUE
+
 /datum/config_entry/flag/save_spritesheets
 	default = FALSE
 

code/controllers/subsystem/asset_loading.dm

@@ -7,6 +7,7 @@ SUBSYSTEM_DEF(asset_loading)
 	flags = SS_NO_INIT
 	runlevels = RUNLEVEL_LOBBY|RUNLEVELS_DEFAULT
 	var/list/datum/asset/generate_queue = list()
+	var/last_queue_len = 0
 
 /datum/controller/subsystem/asset_loading/fire(resumed)
 	while(length(generate_queue))
@@ -16,7 +17,12 @@ SUBSYSTEM_DEF(asset_loading)
 
 		if(MC_TICK_CHECK)
 			return
+		last_queue_len = length(generate_queue)
 		generate_queue.len--
+	// We just emptied the queue
+	if(last_queue_len && !length(generate_queue))
+		// Clean up cached icons, freeing memory.
+		rustg_iconforge_cleanup()
 
 /datum/controller/subsystem/asset_loading/proc/queue_asset(datum/asset/queue)
 #ifdef DO_NOT_DEFER_ASSETS

code/controllers/subsystem/processing/greyscale.dm

@@ -43,6 +43,16 @@ PROCESSING_SUBSYSTEM_DEF(greyscale)
 		CRASH("Invalid colors were given to `GetColoredIconByType()`: [colors]")
 	return configurations[type].Generate(colors)
 
+/datum/controller/subsystem/processing/greyscale/proc/GetColoredIconByTypeUniversalIcon(type, list/colors, target_icon_state)
+	if(!ispath(type, /datum/greyscale_config))
+		CRASH("An invalid greyscale configuration was given to `GetColoredIconByTypeUniversalIcon()`: [type]")
+	type = "[type]"
+	if(istype(colors)) // It's the color list format
+		colors = colors.Join()
+	else if(!istext(colors))
+		CRASH("Invalid colors were given to `GetColoredIconByTypeUniversalIcon()`: [colors]")
+	return configurations[type].GenerateUniversalIcon(colors, target_icon_state)
+
 /datum/controller/subsystem/processing/greyscale/proc/ParseColorString(color_string)
 	. = list()
 	var/list/split_colors = splittext(color_string, "#")

code/datums/achievements/_achievement_data.dm

@@ -76,7 +76,7 @@
 
 /datum/achievement_data/ui_assets(mob/user)
 	return list(
-		get_asset_datum(/datum/asset/spritesheet/simple/achievements),
+		get_asset_datum(/datum/asset/spritesheet_batched/achievements),
 	)
 
 /datum/achievement_data/ui_state(mob/user)
@@ -96,7 +96,7 @@
 	.["progresses"] = list()
 	.["user_key"] = owner_ckey
 
-	var/datum/asset/spritesheet/simple/assets = get_asset_datum(/datum/asset/spritesheet/simple/achievements)
+	var/datum/asset/spritesheet_batched/assets = get_asset_datum(/datum/asset/spritesheet_batched/achievements)
 	for(var/achievement_type in SSachievements.awards)
 		var/datum/award/award = SSachievements.awards[achievement_type]
 		if(!award.name) //No name? we a subtype.

code/datums/browser.dm

@@ -40,6 +40,9 @@
 	if (istype(name, /datum/asset/spritesheet))
 		var/datum/asset/spritesheet/sheet = name
 		stylesheets["spritesheet_[sheet.name].css"] = "data/spritesheets/[sheet.name]"
+	else if (istype(name, /datum/asset/spritesheet_batched))
+		var/datum/asset/spritesheet_batched/sheet = name
+		stylesheets["spritesheet_[sheet.name].css"] = "data/spritesheets/[sheet.name]"
 	else
 		var/asset_name = "[name].css"
 

code/datums/components/crafting/crafting.dm

@@ -504,7 +504,7 @@
 	var/static/list/sprite_sheets
 	if(isnull(sprite_sheets))
 		sprite_sheets = ui_assets()
-	var/datum/asset/spritesheet/sheet = sprite_sheets[mode ? 2 : 1]
+	var/datum/asset/spritesheet_batched/sheet = sprite_sheets[mode ? 2 : 1]
 
 	data["icon_data"] = list()
 	for(var/atom/atom as anything in atoms)
@@ -581,8 +581,8 @@
 
 /datum/component/personal_crafting/ui_assets(mob/user)
 	return list(
-		get_asset_datum(/datum/asset/spritesheet/crafting),
-		get_asset_datum(/datum/asset/spritesheet/crafting/cooking),
+		get_asset_datum(/datum/asset/spritesheet_batched/crafting),
+		get_asset_datum(/datum/asset/spritesheet_batched/crafting/cooking),
 	)
 
 /datum/component/personal_crafting/proc/build_crafting_data(datum/crafting_recipe/recipe)

code/datums/greyscale/_greyscale_config.dm

@@ -306,4 +306,43 @@
 	output["icon"] = GenerateBundle(colors, debug_steps)
 	return output
 
+// ===============
+// Universal Icons
+// ===============
+
+/datum/greyscale_config/proc/GenerateUniversalIcon(color_string, target_bundle_state, datum/universal_icon/last_external_icon)
+	return GenerateBundleUniversalIcon(color_string, target_bundle_state, last_external_icon=last_external_icon)
+
+/// Handles the actual icon manipulation to create the spritesheet
+/datum/greyscale_config/proc/GenerateBundleUniversalIcon(list/colors, target_bundle_state, datum/universal_icon/last_external_icon)
+	if(!istype(colors))
+		colors = SSgreyscale.ParseColorString(colors)
+	if(length(colors) != expected_colors)
+		CRASH("[DebugName()] expected [expected_colors] color arguments but received [length(colors)]")
+
+	if(!(target_bundle_state in icon_states))
+		CRASH("Invalid target bundle icon_state \"[target_bundle_state]\"! Valid icon_states: [icon_states.Join(", ")]")
+
+	var/datum/universal_icon/icon_bundle = GenerateLayerGroupUniversalIcon(colors, icon_states[target_bundle_state], last_external_icon) || uni_icon('icons/effects/effects.dmi', "nothing")
+	icon_bundle.scale(width, height)
+	return icon_bundle
+
+/// Internal recursive proc to handle nested layer groups
+/datum/greyscale_config/proc/GenerateLayerGroupUniversalIcon(list/colors, list/group, datum/universal_icon/last_external_icon)
+	var/datum/universal_icon/new_icon
+	for(var/datum/greyscale_layer/layer as anything in group)
+		var/datum/universal_icon/layer_icon
+		if(islist(layer))
+			layer_icon = GenerateLayerGroupUniversalIcon(colors, layer, new_icon || last_external_icon)
+			var/list/layer_list = layer
+			layer = layer_list[1] // When there are multiple layers in a group like this we use the first one's blend mode
+		else
+			layer_icon = layer.GenerateUniversalIcon(colors, new_icon || last_external_icon)
+
+		if(!new_icon)
+			new_icon = layer_icon
+		else
+			new_icon.blend_icon(layer_icon, layer.blend_mode)
+	return new_icon
+
 #undef MAX_SANE_LAYERS

code/datums/greyscale/layer.dm

@@ -76,16 +76,34 @@
 	var/icon/copy_of_new_icon = icon(new_icon) // Layers shouldn't be modifying it directly, this is just for them to reference
 	return InternalGenerate(processed_colors, render_steps, copy_of_new_icon)
 
+/// Used to actualy create the layer using the given colors
+/// Do not override, use InternalGenerate instead
+/datum/greyscale_layer/proc/GenerateUniversalIcon(list/colors, datum/universal_icon/new_icon)
+	var/list/processed_colors = list()
+	for(var/i in color_ids)
+		if(isnum(i))
+			processed_colors += colors[i]
+		else
+			processed_colors += i
+	var/datum/universal_icon/copy_of_new_icon = isnull(new_icon) ? uni_icon('icons/effects/effects.dmi', "nothing") : new_icon.copy() // Layers shouldn't be modifying it directly, this is just for them to reference
+	return InternalGenerateUniversalIcon(processed_colors, copy_of_new_icon)
+
 /// Override this to implement layers.
 /// The colors var will only contain colors that this layer is configured to use.
 /datum/greyscale_layer/proc/InternalGenerate(list/colors, list/render_steps, icon/new_icon)
 
+/// Override this to implement layers.
+/// The colors var will only contain colors that this layer is configured to use.
+/datum/greyscale_layer/proc/InternalGenerateUniversalIcon(list/colors, datum/universal_icon/new_icon)
+	return new_icon
+
 ////////////////////////////////////////////////////////
 // Subtypes
 
 /// The most basic greyscale layer; a layer which is created from a single icon_state in the given icon file
 /datum/greyscale_layer/icon_state
 	layer_type = "icon_state"
+	var/icon_file
 	var/icon_state
 	var/icon/icon
 	var/color_id
@@ -94,6 +112,7 @@
 	. = ..()
 	if(!icon_exists(icon_file, icon_state))
 		CRASH("Configured icon state \[[icon_state]\] was not found in [icon_file]. Double check your json configuration.")
+	src.icon_file = icon_file
 	icon = new(icon_file, icon_state)
 
 	if(length(color_ids) > 1)
@@ -110,6 +129,13 @@
 		generated_icon.Blend(colors[1], ICON_MULTIPLY)
 	return generated_icon
 
+/datum/greyscale_layer/icon_state/InternalGenerateUniversalIcon(list/colors, datum/universal_icon/new_icon)
+	. = ..()
+	var/datum/universal_icon/generated_icon = uni_icon(icon_file, icon_state)
+	if(length(colors))
+		generated_icon.blend_color(colors[1], ICON_MULTIPLY)
+	return generated_icon
+
 /// A layer to modify the previous layer's colors with a color matrix
 /datum/greyscale_layer/color_matrix
 	layer_type = "color_matrix"
@@ -153,3 +179,8 @@
 	else
 		generated_icon = reference_type.Generate(colors.Join(), new_icon)
 	return icon(generated_icon, icon_state)
+
+/datum/greyscale_layer/reference/InternalGenerateUniversalIcon(list/colors, datum/universal_icon/new_icon)
+	var/datum/universal_icon/generated_icon = reference_type.GenerateUniversalIcon(colors.Join(), icon_state, new_icon)
+	generated_icon = generated_icon.copy()
+	return generated_icon

code/game/machinery/autolathe.dm

@@ -139,7 +139,7 @@
 
 	var/list/output = list()
 
-	var/datum/asset/spritesheet/research_designs/spritesheet = get_asset_datum(/datum/asset/spritesheet/research_designs)
+	var/datum/asset/spritesheet_batched/research_designs/spritesheet = get_asset_datum(/datum/asset/spritesheet_batched/research_designs)
 	var/size32x32 = "[spritesheet.name]32x32"
 
 	for(var/design_id in designs)
@@ -191,8 +191,8 @@
 
 /obj/machinery/autolathe/ui_assets(mob/user)
 	return list(
-		get_asset_datum(/datum/asset/spritesheet/sheetmaterials),
-		get_asset_datum(/datum/asset/spritesheet/research_designs),
+		get_asset_datum(/datum/asset/spritesheet_batched/sheetmaterials),
+		get_asset_datum(/datum/asset/spritesheet_batched/research_designs),
 	)
 
 /obj/machinery/autolathe/ui_data(mob/user)

code/game/machinery/computer/arcade/orion.dm

@@ -143,7 +143,7 @@
 
 /obj/machinery/computer/arcade/orion_trail/ui_assets(mob/user)
 	return list(
-		get_asset_datum(/datum/asset/spritesheet/moods),
+		get_asset_datum(/datum/asset/spritesheet_batched/moods),
 	)
 
 /obj/machinery/computer/arcade/orion_trail/ui_data(mob/user)

code/game/machinery/doors/airlock.dm

@@ -1914,6 +1914,7 @@
 	name = "freezer airlock"
 	icon = 'icons/obj/doors/airlocks/station/freezer.dmi'
 	assemblytype = /obj/structure/door_assembly/door_assembly_fre
+	can_be_glass = FALSE
 
 /obj/machinery/door/airlock/science
 	name = "science airlock"
@@ -2269,6 +2270,7 @@
 	icon = 'icons/obj/doors/airlocks/centcom/centcom.dmi'
 	overlays_file = 'icons/obj/doors/airlocks/centcom/overlays.dmi'
 	assemblytype = /obj/structure/door_assembly/door_assembly_centcom
+	can_be_glass = FALSE
 	normal_integrity = 1000
 	security_level = 6
 	explosion_block = 2
@@ -2277,6 +2279,7 @@
 	icon = 'icons/obj/doors/airlocks/centcom/centcom.dmi'
 	overlays_file = 'icons/obj/doors/airlocks/centcom/overlays.dmi'
 	assemblytype = /obj/structure/door_assembly/door_assembly_grunge
+	can_be_glass = FALSE
 
 
 // Vault Airlocks
@@ -2286,6 +2289,7 @@
 	icon = 'icons/obj/doors/airlocks/vault/vault.dmi'
 	overlays_file = 'icons/obj/doors/airlocks/vault/overlays.dmi'
 	assemblytype = /obj/structure/door_assembly/door_assembly_vault
+	can_be_glass = FALSE
 	explosion_block = 2
 	normal_integrity = 400 // reverse engieneerd: 400 * 1.5 (sec lvl 6) = 600 = original
 	security_level = 6
@@ -2299,6 +2303,7 @@
 	overlays_file = 'icons/obj/doors/airlocks/hatch/overlays.dmi'
 	note_overlay_file = 'icons/obj/doors/airlocks/hatch/overlays.dmi'
 	assemblytype = /obj/structure/door_assembly/door_assembly_hatch
+	can_be_glass = FALSE
 
 /obj/machinery/door/airlock/maintenance_hatch
 	name = "maintenance hatch"
@@ -2306,6 +2311,7 @@
 	overlays_file = 'icons/obj/doors/airlocks/hatch/overlays.dmi'
 	note_overlay_file = 'icons/obj/doors/airlocks/hatch/overlays.dmi'
 	assemblytype = /obj/structure/door_assembly/door_assembly_mhatch
+	can_be_glass = FALSE
 
 // High Security Airlocks
 
@@ -2314,6 +2320,7 @@
 	icon = 'icons/obj/doors/airlocks/highsec/highsec.dmi'
 	overlays_file = 'icons/obj/doors/airlocks/highsec/overlays.dmi'
 	assemblytype = /obj/structure/door_assembly/door_assembly_highsecurity
+	can_be_glass = FALSE
 	explosion_block = 2
 	normal_integrity = 500
 	security_level = 1
@@ -2337,6 +2344,7 @@
 	icon = 'icons/obj/doors/airlocks/abductor/abductor_airlock.dmi'
 	overlays_file = 'icons/obj/doors/airlocks/abductor/overlays.dmi'
 	assemblytype = /obj/structure/door_assembly/door_assembly_abductor
+	can_be_glass = FALSE
 	note_overlay_file = 'icons/obj/doors/airlocks/external/overlays.dmi'
 	damage_deflection = 30
 	explosion_block = 3

code/game/machinery/doors/door.dm

@@ -29,6 +29,8 @@
 	var/visible = TRUE
 	var/operating = FALSE
 	var/glass = FALSE
+	/// If something isn't a glass door but doesn't have a fill_closed icon (no glass slots), this prevents it from being used
+	var/can_be_glass = TRUE
 	/// Do we need to keep track of a filler panel with the airlock
 	var/multi_tile
 	/// A filler object used to fill the space of multi-tile airlocks

code/game/machinery/doors/firedoor.dm

@@ -790,7 +790,7 @@
 
 /obj/machinery/door/firedoor/heavy
 	name = "heavy firelock"
-	icon = 'icons/obj/doors/Doorfire.dmi'
+	icon = 'icons/obj/doors/doorfire.dmi'
 	glass = FALSE
 	explosion_block = 2
 	assemblytype = /obj/structure/firelock_frame/heavy
@@ -805,7 +805,7 @@
 /obj/structure/firelock_frame
 	name = "firelock frame"
 	desc = "A partially completed firelock."
-	icon = 'icons/obj/doors/Doorfire.dmi'
+	icon = 'icons/obj/doors/doorfire.dmi'
 	icon_state = "frame1"
 	base_icon_state = "frame"
 	anchored = FALSE

code/game/machinery/flatpacker.dm

@@ -212,8 +212,8 @@
 
 /obj/machinery/flatpacker/ui_assets(mob/user)
 	return list(
-		get_asset_datum(/datum/asset/spritesheet/sheetmaterials),
-		get_asset_datum(/datum/asset/spritesheet/research_designs),
+		get_asset_datum(/datum/asset/spritesheet_batched/sheetmaterials),
+		get_asset_datum(/datum/asset/spritesheet_batched/research_designs),
 	)
 
 /obj/machinery/flatpacker/ui_static_data(mob/user)

code/game/machinery/telecomms/computers/message.dm

@@ -270,7 +270,7 @@
 
 /obj/machinery/computer/message_monitor/ui_assets(mob/user)
 	. = ..()
-	. += get_asset_datum(/datum/asset/spritesheet/chat)
+	. += get_asset_datum(/datum/asset/spritesheet_batched/chat)
 
 #undef MSG_MON_SCREEN_MAIN
 #undef MSG_MON_SCREEN_LOGS

code/game/machinery/telecomms/computers/telemonitor.dm

@@ -27,7 +27,7 @@
 
 /obj/machinery/computer/telecomms/monitor/ui_assets(mob/user)
 	return list(
-		get_asset_datum(/datum/asset/spritesheet/telecomms),
+		get_asset_datum(/datum/asset/spritesheet_batched/telecomms),
 	)
 
 /obj/machinery/computer/telecomms/monitor/ui_interact(mob/user, datum/tgui/ui)

code/game/objects/items/airlock_painter.dm

@@ -176,7 +176,7 @@
 	/// The full icon state of the decal being printed.
 	var/stored_decal_total = "warningline"
 	/// The type path of the spritesheet being used for the frontend.
-	var/spritesheet_type = /datum/asset/spritesheet/decals // spritesheet containing previews
+	var/spritesheet_type = /datum/asset/spritesheet_batched/decals // spritesheet containing previews
 	/// Does this printer implementation support custom colors?
 	var/supports_custom_color = FALSE
 	/// Current custom color
@@ -266,7 +266,7 @@
 
 /obj/item/airlock_painter/decal/ui_static_data(mob/user)
 	. = ..()
-	var/datum/asset/spritesheet/icon_assets = get_asset_datum(spritesheet_type)
+	var/datum/asset/spritesheet_batched/icon_assets = get_asset_datum(spritesheet_type)
 
 	.["icon_prefix"] = "[icon_assets.name]32x32"
 	.["supports_custom_color"] = supports_custom_color
@@ -332,27 +332,16 @@
 	stored_custom_color = chosen_color
 	stored_color = chosen_color
 
-/datum/asset/spritesheet/decals
+/datum/asset/spritesheet_batched/decals
 	name = "floor_decals"
-
-	/// The floor icon used for blend_preview_floor()
+	ignore_dir_errors = TRUE
+	/// The floor icon used for previews
 	var/preview_floor_icon = 'icons/turf/floors.dmi'
-	/// The floor icon state used for blend_preview_floor()
+	/// The floor icon state used for previews
 	var/preview_floor_state = "floor"
 	/// The associated decal painter type to grab decals, colors, etc from.
 	var/obj/item/airlock_painter/decal/painter_type = /obj/item/airlock_painter/decal
 
-/**
- * Underlay an example floor for preview purposes, and return the new icon.
- *
- * Arguments:
- * * decal - the decal to place over the example floor tile
- */
-/datum/asset/spritesheet/decals/proc/blend_preview_floor(icon/decal)
-	var/icon/final = icon(preview_floor_icon, preview_floor_state)
-	final.Blend(decal, ICON_OVERLAY)
-	return final
-
 /**
  * Insert a specific state into the spritesheet.
  *
@@ -361,14 +350,15 @@
  * * dir - the given direction.
  * * color - the given color.
  */
-/datum/asset/spritesheet/decals/proc/insert_state(decal, dir, color)
+/datum/asset/spritesheet_batched/decals/proc/insert_state(decal, dir, color)
 	// Special case due to icon_state names
 	var/icon_state_color = color == "yellow" ? "" : color
 
-	var/icon/final = blend_preview_floor(icon('icons/turf/decals.dmi', "[decal][icon_state_color ? "_" : ""][icon_state_color]", dir))
-	Insert("[decal]_[dir]_[color]", final)
+	var/datum/universal_icon/floor = uni_icon(preview_floor_icon, preview_floor_state)
+	floor.blend_icon(uni_icon('icons/turf/decals.dmi', "[decal][icon_state_color ? "_" : ""][icon_state_color]", dir), ICON_OVERLAY)
+	insert_icon("[decal]_[dir]_[color]", floor)
 
-/datum/asset/spritesheet/decals/create_spritesheets()
+/datum/asset/spritesheet_batched/decals/create_spritesheets()
 	// Must actually create because initial(type) doesn't work for /lists for some reason.
 	var/obj/item/airlock_painter/decal/painter = new painter_type()
 
@@ -394,7 +384,7 @@
 	stored_dir = 2
 	stored_color = "#D4D4D432"
 	stored_decal = "tile_corner"
-	spritesheet_type = /datum/asset/spritesheet/decals/tiles
+	spritesheet_type = /datum/asset/spritesheet_batched/decals/tiles
 	supports_custom_color = TRUE
 	// Colors can have a an alpha component as RGBA, or just be RGB and use default alpha
 	color_list = list(
@@ -448,11 +438,12 @@
 
 	target.AddElement(/datum/element/decal, 'icons/turf/decals.dmi', source_decal, source_dir, null, null, decal_alpha, decal_color, null, FALSE, null)
 
-/datum/asset/spritesheet/decals/tiles
+/datum/asset/spritesheet_batched/decals/tiles
 	name = "floor_tile_decals"
+	ignore_dir_errors = TRUE
 	painter_type = /obj/item/airlock_painter/decal/tile
 
-/datum/asset/spritesheet/decals/tiles/insert_state(decal, dir, color)
+/datum/asset/spritesheet_batched/decals/tiles/insert_state(decal, dir, color)
 	// Account for 8-sided decals.
 	var/source_decal = decal
 	var/source_dir = dir
@@ -468,13 +459,14 @@
 		render_color = tile_type.rgba_regex.group[1]
 		render_alpha = text2num(tile_type.rgba_regex.group[2], 16)
 
-	var/icon/colored_icon = icon('icons/turf/decals.dmi', source_decal, dir=source_dir)
-	colored_icon.ChangeOpacity(render_alpha * 0.008)
+	var/datum/universal_icon/colored_icon = uni_icon('icons/turf/decals.dmi', source_decal, dir=source_dir)
+	colored_icon.change_opacity(render_alpha / 255)
 	if(color == "custom")
 		// Do a fun rainbow pattern to stand out while still being static.
-		colored_icon.Blend(icon('icons/effects/random_spawners.dmi', "rainbow"), ICON_MULTIPLY)
+		colored_icon.blend_icon(uni_icon('icons/effects/random_spawners.dmi', "rainbow"), ICON_MULTIPLY)
 	else
-		colored_icon.Blend(render_color, ICON_MULTIPLY)
+		colored_icon.blend_color(render_color, ICON_MULTIPLY)
 
-	colored_icon = blend_preview_floor(colored_icon)
-	Insert("[decal]_[dir]_[replacetext(color, "#", "")]", colored_icon)
+	var/datum/universal_icon/floor = uni_icon(preview_floor_icon, preview_floor_state)
+	floor.blend_icon(colored_icon, ICON_OVERLAY)
+	insert_icon("[decal]_[dir]_[replacetext(color, "#", "")]", floor)

code/game/objects/items/rcd/RCD.dm

@@ -314,7 +314,7 @@
 
 /obj/item/construction/rcd/ui_assets(mob/user)
 	return list(
-		get_asset_datum(/datum/asset/spritesheet/rcd),
+		get_asset_datum(/datum/asset/spritesheet_batched/rcd),
 	)
 
 /obj/item/construction/rcd/ui_host(mob/user)

code/game/objects/items/rcd/RPD.dm

@@ -148,7 +148,7 @@
 
 /obj/item/pipe_dispenser/ui_assets(mob/user)
 	return list(
-		get_asset_datum(/datum/asset/spritesheet/pipes),
+		get_asset_datum(/datum/asset/spritesheet_batched/pipes),
 	)
 
 /obj/item/pipe_dispenser/ui_interact(mob/user, datum/tgui/ui)

code/game/objects/items/rcd/RPLD.dm

@@ -113,7 +113,7 @@
 
 /obj/item/construction/plumbing/ui_assets(mob/user)
 	return list(
-		get_asset_datum(/datum/asset/spritesheet/plumbing),
+		get_asset_datum(/datum/asset/spritesheet_batched/plumbing),
 	)
 
 /obj/item/construction/plumbing/ui_static_data(mob/user)

code/game/objects/items/rcd/RTD.dm

@@ -144,7 +144,7 @@
 
 /obj/item/construction/rtd/ui_assets(mob/user)
 	return list(
-		get_asset_datum(/datum/asset/spritesheet/rtd),
+		get_asset_datum(/datum/asset/spritesheet_batched/rtd),
 	)
 
 /obj/item/construction/rtd/attack_self(mob/user)

code/modules/admin/admin_verbs.dm

@@ -680,6 +680,33 @@ ADMIN_VERB(give_ai_controller, R_FUN, "Give AI Controller", ADMIN_VERB_NO_DESCRI
 	var/datum/admin_ai_template/using_template = new chosen_type
 	using_template.apply(my_guy, user)
 
+ADMIN_VERB(clear_legacy_asset_cache, R_DEBUG, "Clear Legacy Asset Cache", "Clears the legacy asset cache, regenerating it immediately (may cause lag).", ADMIN_CATEGORY_DEBUG)
+	if(!CONFIG_GET(flag/cache_assets))
+		to_chat(user, span_warning("Asset caching is disabled in the config!"))
+		return
+	var/regenerated = 0
+	for(var/datum/asset/target_spritesheet as anything in subtypesof(/datum/asset))
+		if(!initial(target_spritesheet.cross_round_cachable))
+			continue
+		if(target_spritesheet == initial(target_spritesheet._abstract))
+			continue
+		var/datum/asset/asset_datum = GLOB.asset_datums[target_spritesheet]
+		asset_datum.regenerate()
+		regenerated++
+	to_chat(user, span_notice("Regenerated [regenerated] asset\s."))
+
+ADMIN_VERB(clear_smart_asset_cache, R_DEBUG, "Clear Smart Asset Cache", "Clear the smart asset cache, causing it to regenerate next round.", ADMIN_CATEGORY_DEBUG)
+	if(!CONFIG_GET(flag/smart_cache_assets))
+		to_chat(user, span_warning("Smart asset caching is disabled in the config!"))
+		return
+	var/cleared = 0
+	for(var/datum/asset/spritesheet_batched/target_spritesheet as anything in subtypesof(/datum/asset/spritesheet_batched))
+		if(target_spritesheet == initial(target_spritesheet._abstract))
+			continue
+		fdel("[ASSET_CROSS_ROUND_SMART_CACHE_DIRECTORY]/spritesheet_cache.[initial(target_spritesheet.name)].json")
+		cleared++
+	to_chat(user, span_notice("Cleared [cleared] asset\s."))
+
 ADMIN_VERB(give_ai_speech, R_FUN, "Give Random AI Speech", ADMIN_VERB_NO_DESCRIPTION, ADMIN_CATEGORY_HIDDEN, mob/living/my_guy)
 	if (isnull(my_guy.ai_controller))
 		var/create_controller = tgui_alert(user, "Target has no AI controller, add one?", "Give AI?", list("Yes", "No")) == "Yes"

code/modules/admin/verbs/light_debug.dm

@@ -198,7 +198,7 @@ GLOBAL_LIST_EMPTY(light_debugged_atoms)
 		ui.open()
 
 /atom/movable/screen/light_button/edit/ui_assets(mob/user)
-	return list(get_asset_datum(/datum/asset/spritesheet/lights))
+	return list(get_asset_datum(/datum/asset/spritesheet_batched/lights))
 
 /atom/movable/screen/light_button/edit/ui_data()
 	var/list/data = list()
@@ -371,7 +371,7 @@ GLOBAL_LIST_EMPTY(light_debugged_atoms)
 		ui.open()
 
 /datum/action/spawn_light/ui_assets(mob/user)
-	return list(get_asset_datum(/datum/asset/spritesheet/lights))
+	return list(get_asset_datum(/datum/asset/spritesheet_batched/lights))
 
 /datum/action/spawn_light/ui_data()
 	var/list/data = list()

code/modules/asset_cache/asset_list.dm

@@ -1,5 +1,3 @@
-#define ASSET_CROSS_ROUND_CACHE_DIRECTORY "cache/assets"
-
 //These datums are used to populate the asset cache, the proc "register()" does this.
 //Place any asset datums you create in asset_list_items.dm
 
@@ -63,6 +61,17 @@ GLOBAL_LIST_EMPTY(asset_datums)
 /datum/asset/proc/should_refresh()
 	return !cross_round_cachable || !CONFIG_GET(flag/cache_assets)
 
+/// Immediately regenerate the asset, overwriting any cache.
+/datum/asset/proc/regenerate()
+	unregister()
+	cached_serialized_url_mappings = null
+	cached_serialized_url_mappings_transport_type = null
+	register()
+
+/// Unregisters any assets from the transport.
+/datum/asset/proc/unregister()
+	CRASH("unregister() not implemented for asset [type]!")
+
 /// Simply takes any generated file and saves it to the round-specific /logs folder. Useful for debugging potential issues with spritesheet generation/display.
 /// Only called when the SAVE_SPRITESHEETS config option is uncommented.
 /datum/asset/proc/save_to_logs(file_name, file_location)
@@ -103,6 +112,10 @@ GLOBAL_LIST_EMPTY(asset_datums)
 	for (var/asset_name in assets)
 		.[asset_name] = SSassets.transport.get_asset_url(asset_name, assets[asset_name])
 
+/datum/asset/simple/unregister()
+	for (var/asset_name in assets)
+		SSassets.transport.unregister_asset(asset_name)
+
 // For registering or sending multiple others at once
 /datum/asset/group
 	_abstract = /datum/asset/group
@@ -123,374 +136,10 @@ GLOBAL_LIST_EMPTY(asset_datums)
 		var/datum/asset/A = get_asset_datum(type)
 		. += A.get_url_mappings()
 
-// spritesheet implementation - coalesces various icons into a single .png file
-// and uses CSS to select icons out of that file - saves on transferring some
-// 1400-odd individual PNG files
-#define SPR_SIZE 1
-#define SPR_IDX 2
-#define SPRSZ_COUNT 1
-#define SPRSZ_ICON 2
-#define SPRSZ_STRIPPED 3
-
-/datum/asset/spritesheet
-	_abstract = /datum/asset/spritesheet
-	cross_round_cachable = TRUE
-	var/name
-	/// List of arguments to pass into queuedInsert
-	/// Exists so we can queue icon insertion, mostly for stuff like preferences
-	var/list/to_generate = list()
-	var/list/sizes = list()    // "32x32" -> list(10, icon/normal, icon/stripped)
-	var/list/sprites = list()  // "foo_bar" -> list("32x32", 5)
-	var/list/cached_spritesheets_needed
-	var/generating_cache = FALSE
-	var/fully_generated = FALSE
-	/// If this asset should be fully loaded on new
-	/// Defaults to false so we can process this stuff nicely
-	var/load_immediately = FALSE
-	VAR_PRIVATE
-		// Kept in state so that the result is the same, even when the files are created, for this run
-		should_refresh = null
-
-/datum/asset/spritesheet/proc/should_load_immediately()
-#ifdef DO_NOT_DEFER_ASSETS
-	return TRUE
-#else
-	return load_immediately
-#endif
-
-
-/datum/asset/spritesheet/should_refresh()
-	if (..())
-		return TRUE
-
-	if (isnull(should_refresh))
-		// `fexists` seems to always fail on static-time
-		should_refresh = !fexists(css_cache_filename()) || !fexists(data_cache_filename())
-
-	return should_refresh
-
-/datum/asset/spritesheet/register()
-	SHOULD_NOT_OVERRIDE(TRUE)
-
-	if (!name)
-		CRASH("spritesheet [type] cannot register without a name")
-
-	if (!should_refresh() && read_from_cache())
-		fully_generated = TRUE
-		return
-
-	// If it's cached, may as well load it now, while the loading is cheap
-	if(CONFIG_GET(flag/cache_assets) && cross_round_cachable)
-		load_immediately = TRUE
-
-	create_spritesheets()
-	if(should_load_immediately())
-		realize_spritesheets(yield = FALSE)
-	else
-		SSasset_loading.queue_asset(src)
-
-/datum/asset/spritesheet/proc/realize_spritesheets(yield)
-	if(fully_generated)
-		return
-	while(length(to_generate))
-		var/list/stored_args = to_generate[to_generate.len]
-		to_generate.len--
-		queuedInsert(arglist(stored_args))
-		if(yield && TICK_CHECK)
-			return
-
-	ensure_stripped()
-	for(var/size_id in sizes)
-		var/size = sizes[size_id]
-		SSassets.transport.register_asset("[name]_[size_id].png", size[SPRSZ_STRIPPED])
-	var/css_name = "spritesheet_[name].css"
-	var/file_directory = "data/spritesheets/[css_name]"
-	fdel(file_directory)
-	text2file(generate_css(), file_directory)
-	SSassets.transport.register_asset(css_name, fcopy_rsc(file_directory))
-
-	if(CONFIG_GET(flag/save_spritesheets))
-		save_to_logs(file_name = css_name, file_location = file_directory)
-
-	fdel(file_directory)
-
-	if (CONFIG_GET(flag/cache_assets) && cross_round_cachable)
-		write_to_cache()
-	fully_generated = TRUE
-	// If we were ever in there, remove ourselves
-	SSasset_loading.dequeue_asset(src)
-
-/datum/asset/spritesheet/queued_generation()
-	realize_spritesheets(yield = TRUE)
-
-/datum/asset/spritesheet/ensure_ready()
-	if(!fully_generated)
-		realize_spritesheets(yield = FALSE)
-	return ..()
-
-/datum/asset/spritesheet/send(client/client)
-	if (!name)
-		return
-
-	if (!should_refresh())
-		return send_from_cache(client)
-
-	var/all = list("spritesheet_[name].css")
-	for(var/size_id in sizes)
-		all += "[name]_[size_id].png"
-	. = SSassets.transport.send_assets(client, all)
-
-/datum/asset/spritesheet/get_url_mappings()
-	if (!name)
-		return
-
-	if (!should_refresh())
-		return get_cached_url_mappings()
-
-	. = list("spritesheet_[name].css" = SSassets.transport.get_asset_url("spritesheet_[name].css"))
-	for(var/size_id in sizes)
-		.["[name]_[size_id].png"] = SSassets.transport.get_asset_url("[name]_[size_id].png")
-
-/datum/asset/spritesheet/proc/ensure_stripped(sizes_to_strip = sizes)
-	for(var/size_id in sizes_to_strip)
-		var/size = sizes[size_id]
-		if (size[SPRSZ_STRIPPED])
-			continue
-
-		// save flattened version
-		var/png_name = "[name]_[size_id].png"
-		var/file_directory = "data/spritesheets/[png_name]"
-		fcopy(size[SPRSZ_ICON], file_directory)
-		var/error = rustg_dmi_strip_metadata(file_directory)
-		if(length(error))
-			stack_trace("Failed to strip [png_name]: [error]")
-		size[SPRSZ_STRIPPED] = icon(file_directory)
-
-		// this is useful here for determining if weird sprite issues (like having a white background) are a cause of what we're doing DM-side or not since we can see the full flattened thing at-a-glance.
-		if(CONFIG_GET(flag/save_spritesheets))
-			save_to_logs(file_name = png_name, file_location = file_directory)
-
-		fdel(file_directory)
-
-/datum/asset/spritesheet/proc/generate_css()
-	var/list/out = list()
-
-	for (var/size_id in sizes)
-		var/size = sizes[size_id]
-		var/icon/tiny = size[SPRSZ_ICON]
-		out += ".[name][size_id]{display:inline-block;width:[tiny.Width()]px;height:[tiny.Height()]px;background:url('[get_background_url("[name]_[size_id].png")]') no-repeat;}"
-
-	for (var/sprite_id in sprites)
-		var/sprite = sprites[sprite_id]
-		var/size_id = sprite[SPR_SIZE]
-		var/idx = sprite[SPR_IDX]
-		var/size = sizes[size_id]
-
-		var/icon/tiny = size[SPRSZ_ICON]
-		var/icon/big = size[SPRSZ_STRIPPED]
-		var/per_line = big.Width() / tiny.Width()
-		var/x = (idx % per_line) * tiny.Width()
-		var/y = round(idx / per_line) * tiny.Height()
-
-		out += ".[name][size_id].[sprite_id]{background-position:-[x]px -[y]px;}"
-
-	return out.Join("\n")
-
-/datum/asset/spritesheet/proc/css_cache_filename()
-	return "[ASSET_CROSS_ROUND_CACHE_DIRECTORY]/spritesheet.[name].css"
-
-/datum/asset/spritesheet/proc/data_cache_filename()
-	return "[ASSET_CROSS_ROUND_CACHE_DIRECTORY]/spritesheet.[name].json"
-
-/datum/asset/spritesheet/proc/read_from_cache()
-	return read_css_from_cache() && read_data_from_cache()
-
-/datum/asset/spritesheet/proc/read_css_from_cache()
-	var/replaced_css = file2text(css_cache_filename())
-
-	var/regex/find_background_urls = regex(@"background:url\('%(.+?)%'\)", "g")
-	while (find_background_urls.Find(replaced_css))
-		var/asset_id = find_background_urls.group[1]
-		var/asset_cache_item = SSassets.transport.register_asset(asset_id, "[ASSET_CROSS_ROUND_CACHE_DIRECTORY]/spritesheet.[asset_id]")
-		var/asset_url = SSassets.transport.get_asset_url(asset_cache_item = asset_cache_item)
-		replaced_css = replacetext(replaced_css, find_background_urls.match, "background:url('[asset_url]')")
-		LAZYADD(cached_spritesheets_needed, asset_id)
-
-	var/finalized_name = "spritesheet_[name].css"
-	var/replaced_css_filename = "data/spritesheets/[finalized_name]"
-	rustg_file_write(replaced_css, replaced_css_filename)
-	SSassets.transport.register_asset(finalized_name, replaced_css_filename)
-
-	if(CONFIG_GET(flag/save_spritesheets))
-		save_to_logs(file_name = finalized_name, file_location = replaced_css_filename)
-
-	fdel(replaced_css_filename)
-
-	return TRUE
-
-/datum/asset/spritesheet/proc/read_data_from_cache()
-	var/json = json_decode(file2text(data_cache_filename()))
-
-	if (islist(json["sprites"]))
-		sprites = json["sprites"]
-
-	return TRUE
-
-/datum/asset/spritesheet/proc/send_from_cache(client/client)
-	if (isnull(cached_spritesheets_needed))
-		stack_trace("cached_spritesheets_needed was null when sending assets from [type] from cache")
-		cached_spritesheets_needed = list()
-
-	return SSassets.transport.send_assets(client, cached_spritesheets_needed + "spritesheet_[name].css")
-
-/// Returns the URL to put in the background:url of the CSS asset
-/datum/asset/spritesheet/proc/get_background_url(asset)
-	if (generating_cache)
-		return "%[asset]%"
-	else
-		return SSassets.transport.get_asset_url(asset)
-
-/datum/asset/spritesheet/proc/write_to_cache()
-	write_css_to_cache()
-	write_data_to_cache()
-
-/datum/asset/spritesheet/proc/write_css_to_cache()
-	for (var/size_id in sizes)
-		fcopy(SSassets.cache["[name]_[size_id].png"].resource, "[ASSET_CROSS_ROUND_CACHE_DIRECTORY]/spritesheet.[name]_[size_id].png")
-
-	generating_cache = TRUE
-	var/mock_css = generate_css()
-	generating_cache = FALSE
-
-	rustg_file_write(mock_css, css_cache_filename())
-
-/datum/asset/spritesheet/proc/write_data_to_cache()
-	rustg_file_write(json_encode(list(
-		"sprites" = sprites,
-	)), data_cache_filename())
-
-/datum/asset/spritesheet/proc/get_cached_url_mappings()
-	var/list/mappings = list()
-	mappings["spritesheet_[name].css"] = SSassets.transport.get_asset_url("spritesheet_[name].css")
-
-	for (var/asset_name in cached_spritesheets_needed)
-		mappings[asset_name] = SSassets.transport.get_asset_url(asset_name)
-
-	return mappings
-
-/// Override this in order to start the creation of the spritehseet.
-/// This is where all your Insert, InsertAll, etc calls should be inside.
-/datum/asset/spritesheet/proc/create_spritesheets()
-	SHOULD_CALL_PARENT(FALSE)
-	CRASH("create_spritesheets() not implemented for [type]!")
-
-/datum/asset/spritesheet/proc/Insert(sprite_name, icon/I, icon_state="", dir=SOUTH, frame=1, moving=FALSE)
-	if(should_load_immediately())
-		queuedInsert(sprite_name, I, icon_state, dir, frame, moving)
-	else
-		to_generate += list(args.Copy())
-
-/datum/asset/spritesheet/proc/queuedInsert(sprite_name, icon/I, icon_state="", dir=SOUTH, frame=1, moving=FALSE)
-#ifdef UNIT_TESTS
-	if (I && icon_state && !icon_exists(I, icon_state)) // check the base icon prior to extracting the state we want
-		stack_trace("Tried to insert nonexistent icon_state '[icon_state]' from [I] into spritesheet [name] ([type])")
-		return
-#endif
-	I = icon(I, icon_state=icon_state, dir=dir, frame=frame, moving=moving)
-	if (!I || !length(icon_states(I)))  // that direction or state doesn't exist
-		return
-
-	var/start_usage = world.tick_usage
-
-	//any sprite modifications we want to do (aka, coloring a greyscaled asset)
-	I = ModifyInserted(I)
-	var/size_id = "[I.Width()]x[I.Height()]"
-	var/size = sizes[size_id]
-
-	if (sprites[sprite_name])
-		CRASH("duplicate sprite \"[sprite_name]\" in sheet [name] ([type])")
-
-	if (size)
-		var/position = size[SPRSZ_COUNT]++
-		// Icons are essentially representations of files + modifications
-		// Because of this, byond keeps them in a cache. It does this in a really dumb way tho
-		// It's essentially a FIFO queue. So after we do icon() some amount of times, our old icons go out of cache
-		// When this happens it becomes impossible to modify them, trying to do so will instead throw a
-		// "bad icon" error.
-		// What we're doing here is ensuring our icon is in the cache by refreshing it, so we can modify it w/o runtimes.
-		var/icon/sheet = size[SPRSZ_ICON]
-		var/icon/sheet_copy = icon(sheet)
-		size[SPRSZ_STRIPPED] = null
-		sheet_copy.Insert(I, icon_state=sprite_name)
-		size[SPRSZ_ICON] = sheet_copy
-
-		sprites[sprite_name] = list(size_id, position)
-	else
-		sizes[size_id] = size = list(1, I, null)
-		sprites[sprite_name] = list(size_id, 0)
-
-	SSblackbox.record_feedback("tally", "spritesheet_queued_insert_time", TICK_USAGE_TO_MS(start_usage), name)
-
-/**
- * A simple proc handing the Icon for you to modify before it gets turned into an asset.
- *
- * Arguments:
- * * I: icon being turned into an asset
- */
-/datum/asset/spritesheet/proc/ModifyInserted(icon/pre_asset)
-	return pre_asset
-
-/datum/asset/spritesheet/proc/InsertAll(prefix, icon/I, list/directions)
-	if (length(prefix))
-		prefix = "[prefix]-"
-
-	if (!directions)
-		directions = list(SOUTH)
-
-	for (var/icon_state_name in icon_states(I))
-		for (var/direction in directions)
-			var/prefix2 = (directions.len > 1) ? "[dir2text(direction)]-" : ""
-			Insert("[prefix][prefix2][icon_state_name]", I, icon_state=icon_state_name, dir=direction)
-
-/datum/asset/spritesheet/proc/css_tag()
-	return {"<link rel="stylesheet" href="[css_filename()]" />"}
-
-/datum/asset/spritesheet/proc/css_filename()
-	return SSassets.transport.get_asset_url("spritesheet_[name].css")
-
-/datum/asset/spritesheet/proc/icon_tag(sprite_name)
-	var/sprite = sprites[sprite_name]
-	if (!sprite)
-		return null
-	var/size_id = sprite[SPR_SIZE]
-	return {"<span class='[name][size_id] [sprite_name]'></span>"}
-
-/datum/asset/spritesheet/proc/icon_class_name(sprite_name)
-	var/sprite = sprites[sprite_name]
-	if (!sprite)
-		return null
-	var/size_id = sprite[SPR_SIZE]
-	return {"[name][size_id] [sprite_name]"}
-
-/**
- * Returns the size class (ex design32x32) for a given sprite's icon
- *
- * Arguments:
- * * sprite_name - The sprite to get the size of
- */
-/datum/asset/spritesheet/proc/icon_size_id(sprite_name)
-	var/sprite = sprites[sprite_name]
-	if (!sprite)
-		return null
-	var/size_id = sprite[SPR_SIZE]
-	return "[name][size_id]"
-
-#undef SPR_SIZE
-#undef SPR_IDX
-#undef SPRSZ_COUNT
-#undef SPRSZ_ICON
-#undef SPRSZ_STRIPPED
-
+/datum/asset/group/unregister()
+	for (var/type in children)
+		var/datum/asset/A = get_asset_datum(type)
+		A.unregister()
 
 /datum/asset/changelog_item
 	_abstract = /datum/asset/changelog_item
@@ -510,13 +159,10 @@ GLOBAL_LIST_EMPTY(asset_datums)
 		return
 	. = list("[item_filename]" = SSassets.transport.get_asset_url(item_filename))
 
-/datum/asset/spritesheet/simple
-	_abstract = /datum/asset/spritesheet/simple
-	var/list/assets
-
-/datum/asset/spritesheet/simple/create_spritesheets()
-	for (var/key in assets)
-		Insert(key, assets[key])
+/datum/asset/changelog_item/unregister()
+	if (!item_filename)
+		return
+	SSassets.transport.unregister_asset(item_filename)
 
 //Generates assets based on iconstates of a single icon
 /datum/asset/simple/icon_states
@@ -617,13 +263,13 @@ GLOBAL_LIST_EMPTY(asset_datums)
 /datum/asset/json/register()
 	var/filename = "data/[name].json"
 	fdel(filename)
-	text2file(json_encode(generate()), filename)
+	rustg_file_write(json_encode(generate()), filename)
 	SSassets.transport.register_asset("[name].json", fcopy_rsc(filename))
 	fdel(filename)
 
 /// Returns the data that will be JSON encoded
 /datum/asset/json/proc/generate()
-	SHOULD_CALL_PARENT(FALSE)
 	CRASH("generate() not implemented for [type]!")
 
-#undef ASSET_CROSS_ROUND_CACHE_DIRECTORY
+/datum/asset/json/unregister()
+	SSassets.transport.unregister_asset("[name].json")

code/modules/asset_cache/assets/achievements.dm

@@ -1,11 +1,13 @@
-/datum/asset/spritesheet/simple/achievements
+/datum/asset/spritesheet_batched/achievements
 	name = "achievements"
 
-/datum/asset/spritesheet/simple/achievements/create_spritesheets()
-	InsertAll("achievement", ACHIEVEMENTS_SET)
+/datum/asset/spritesheet_batched/achievements/create_spritesheets()
+	for(var/icon_state_name in icon_states(ACHIEVEMENTS_SET))
+		insert_icon("achievement-[icon_state_name]", uni_icon(ACHIEVEMENTS_SET, icon_state_name))
 	// catch achievements which are pulling icons from another file
 	for(var/datum/award/other_award as anything in subtypesof(/datum/award))
 		var/icon = initial(other_award.icon)
-		if (icon != ACHIEVEMENTS_SET)
-			var/icon_state = initial(other_award.icon_state)
-			Insert("achievement-[icon_state]", icon, icon_state=icon_state)
+		if (icon == ACHIEVEMENTS_SET)
+			continue
+		var/icon_state_name = initial(other_award.icon_state)
+		insert_icon("achievement-[icon_state_name]", uni_icon(icon, icon_state_name))

code/modules/asset_cache/assets/bibles.dm

@@ -1,10 +1,11 @@
-/datum/asset/spritesheet/bibles
+/datum/asset/spritesheet_batched/bibles
 	name = "bibles"
 
-/datum/asset/spritesheet/bibles/create_spritesheets()
+/datum/asset/spritesheet_batched/bibles/create_spritesheets()
 	var/obj/item/book/bible/holy_template = /obj/item/book/bible
-	InsertAll("display", initial(holy_template.icon))
+	var/target_icon = initial(holy_template.icon)
+	var/datum/icon_transformer/transform = new()
+	transform.scale(224, 224) // Scale up by 7x
 
-/datum/asset/spritesheet/bibles/ModifyInserted(icon/pre_asset)
-	pre_asset.Scale(224, 224) // Scale up by 7x
-	return pre_asset
+	for (var/icon_state_name in icon_states(target_icon))
+		insert_icon("display-[icon_state_name]", uni_icon(target_icon, icon_state_name, transform=transform))

code/modules/asset_cache/assets/chat.dm

@@ -1,14 +1,13 @@
-/datum/asset/spritesheet/chat
+/datum/asset/spritesheet_batched/chat
 	name = "chat"
 
-/datum/asset/spritesheet/chat/create_spritesheets()
-	InsertAll("emoji", EMOJI_SET)
+/datum/asset/spritesheet_batched/chat/create_spritesheets()
+	insert_all_icons("emoji", EMOJI_SET)
 	// pre-loading all lanugage icons also helps to avoid meta
-	InsertAll("language", 'icons/ui/chat/language.dmi')
+	insert_all_icons("language", 'icons/ui/chat/language.dmi')
 	// catch languages which are pulling icons from another file
-	for(var/path in typesof(/datum/language))
-		var/datum/language/L = path
+	for(var/datum/language/L as anything in subtypesof(/datum/language))
 		var/icon = initial(L.icon)
 		if (icon != 'icons/ui/chat/language.dmi')
 			var/icon_state = initial(L.icon_state)
-			Insert("language-[icon_state]", icon, icon_state=icon_state)
+			insert_icon("language-[icon_state]", uni_icon(icon, icon_state))

code/modules/asset_cache/assets/chemmaster.dm

@@ -1,8 +1,8 @@
 ///Icons for containers printed in ChemMaster
-/datum/asset/spritesheet/chemmaster
+/datum/asset/spritesheet_batched/chemmaster
 	name = "chemmaster"
 
-/datum/asset/spritesheet/chemmaster/create_spritesheets()
+/datum/asset/spritesheet_batched/chemmaster/create_spritesheets()
 	var/list/ids = list()
 	for(var/category in GLOB.reagent_containers)
 		for(var/obj/item/reagent_containers/container as anything in GLOB.reagent_containers[category])
@@ -12,4 +12,4 @@
 			if(id in ids) // exclude duplicate containers
 				continue
 			ids += id
-			Insert(id, icon_file, icon_state)
+			insert_icon(id, uni_icon(icon_file, icon_state))

code/modules/asset_cache/assets/condiments.dm

@@ -1,24 +0,0 @@
-/datum/asset/spritesheet/simple/condiments
-	name = "condiments"
-	assets = list(
-		CONDIMASTER_STYLE_FALLBACK = 'icons/ui/condiments/bottle.png',
-		"flour" = 'icons/ui/condiments/flour.png',
-		"rice" = 'icons/ui/condiments/rice.png',
-		"sugar" = 'icons/ui/condiments/sugar.png',
-		"milk" = 'icons/ui/condiments/milk.png',
-		"enzyme" = 'icons/ui/condiments/enzyme.png',
-		"capsaicin" = 'icons/ui/condiments/hotsauce.png',
-		"frostoil" = 'icons/ui/condiments/coldsauce.png',
-		"bbqsauce" = 'icons/ui/condiments/bbqsauce.png',
-		"soymilk" = 'icons/ui/condiments/soymilk.png',
-		"soysauce" = 'icons/ui/condiments/soysauce.png',
-		"ketchup" = 'icons/ui/condiments/ketchup.png',
-		"mayonnaise" = 'icons/ui/condiments/mayonnaise.png',
-		"oliveoil" = 'icons/ui/condiments/oliveoil.png',
-		"cooking_oil" = 'icons/ui/condiments/cookingoil.png',
-		"peanut_butter" = 'icons/ui/condiments/peanutbutter.png',
-		"cherryjelly" = 'icons/ui/condiments/cherryjelly.png',
-		"honey" = 'icons/ui/condiments/honey.png',
-		"blackpepper" = 'icons/ui/condiments/peppermillsmall.png',
-		"sodiumchloride" = 'icons/ui/condiments/saltshakersmall.png',
-	)

code/modules/asset_cache/assets/crafting.dm

@@ -1,17 +1,17 @@
 ///Representative icons for the contents of each crafting recipe
-/datum/asset/spritesheet/crafting
+/datum/asset/spritesheet_batched/crafting
 	name = "crafting"
 
-/datum/asset/spritesheet/crafting/create_spritesheets()
+/datum/asset/spritesheet_batched/crafting/create_spritesheets()
 	var/id = 1
 	for(var/atom in GLOB.crafting_recipes_atoms)
 		add_atom_icon(atom, id++)
 	add_tool_icons()
 
-/datum/asset/spritesheet/crafting/cooking
+/datum/asset/spritesheet_batched/crafting/cooking
 	name = "cooking"
 
-/datum/asset/spritesheet/crafting/cooking/create_spritesheets()
+/datum/asset/spritesheet_batched/crafting/cooking/create_spritesheets()
 	var/id = 1
 	for(var/atom in GLOB.cooking_recipes_atoms)
 		add_atom_icon(atom, id++)
@@ -24,7 +24,7 @@
  * If it a reagent, it will use the default container's icon state,
  * OR if it has a glass style associated, it will use that
  */
-/datum/asset/spritesheet/crafting/proc/add_atom_icon(ingredient_typepath, id)
+/datum/asset/spritesheet_batched/crafting/proc/add_atom_icon(ingredient_typepath, id)
 	var/icon_file
 	var/icon_state
 	var/obj/preview_item = ingredient_typepath
@@ -43,32 +43,32 @@
 		if(!icon_exists_or_scream(icon_file, icon_state))
 			return
 
-	Insert("a[id]", icon(icon_file, icon_state, SOUTH))
+	insert_icon("a[id]", uni_icon(icon_file, icon_state, SOUTH))
 
 ///Adds tool icons to the spritesheet
-/datum/asset/spritesheet/crafting/proc/add_tool_icons()
+/datum/asset/spritesheet_batched/crafting/proc/add_tool_icons()
 	var/list/tool_icons = list(
-		TOOL_CROWBAR = icon('icons/obj/tools.dmi', "crowbar"),
-		TOOL_MULTITOOL = icon('icons/obj/devices/tool.dmi', "multitool"),
-		TOOL_SCREWDRIVER = icon('icons/obj/tools.dmi', "screwdriver_map"),
-		TOOL_WIRECUTTER = icon('icons/obj/tools.dmi', "cutters_map"),
-		TOOL_WRENCH = icon('icons/obj/tools.dmi', "wrench"),
-		TOOL_WELDER = icon('icons/obj/tools.dmi', "welder"),
-		TOOL_ANALYZER = icon('icons/obj/devices/scanner.dmi', "analyzer"),
-		TOOL_MINING = icon('icons/obj/mining.dmi', "minipick"),
-		TOOL_SHOVEL = icon('icons/obj/mining.dmi', "spade"),
-		TOOL_RETRACTOR = icon('icons/obj/medical/surgery_tools.dmi', "retractor"),
-		TOOL_HEMOSTAT = icon('icons/obj/medical/surgery_tools.dmi', "hemostat"),
-		TOOL_CAUTERY = icon('icons/obj/medical/surgery_tools.dmi', "cautery"),
-		TOOL_DRILL = icon('icons/obj/medical/surgery_tools.dmi', "drill"),
-		TOOL_SCALPEL = icon('icons/obj/medical/surgery_tools.dmi', "scalpel"),
-		TOOL_SAW = icon('icons/obj/medical/surgery_tools.dmi', "saw"),
-		TOOL_BONESET = icon('icons/obj/medical/surgery_tools.dmi', "bonesetter"),
-		TOOL_KNIFE = icon('icons/obj/service/kitchen.dmi', "knife"),
-		TOOL_BLOODFILTER = icon('icons/obj/medical/surgery_tools.dmi', "bloodfilter"),
-		TOOL_ROLLINGPIN = icon('icons/obj/service/kitchen.dmi', "rolling_pin"),
-		TOOL_RUSTSCRAPER = icon('icons/obj/tools.dmi', "wirebrush"),
+		TOOL_CROWBAR = uni_icon('icons/obj/tools.dmi', "crowbar"),
+		TOOL_MULTITOOL = uni_icon('icons/obj/devices/tool.dmi', "multitool"),
+		TOOL_SCREWDRIVER = uni_icon('icons/obj/tools.dmi', "screwdriver_map"),
+		TOOL_WIRECUTTER = uni_icon('icons/obj/tools.dmi', "cutters_map"),
+		TOOL_WRENCH = uni_icon('icons/obj/tools.dmi', "wrench"),
+		TOOL_WELDER = uni_icon('icons/obj/tools.dmi', "welder"),
+		TOOL_ANALYZER = uni_icon('icons/obj/devices/scanner.dmi', "analyzer"),
+		TOOL_MINING = uni_icon('icons/obj/mining.dmi', "minipick"),
+		TOOL_SHOVEL = uni_icon('icons/obj/mining.dmi', "spade"),
+		TOOL_RETRACTOR = uni_icon('icons/obj/medical/surgery_tools.dmi', "retractor"),
+		TOOL_HEMOSTAT = uni_icon('icons/obj/medical/surgery_tools.dmi', "hemostat"),
+		TOOL_CAUTERY = uni_icon('icons/obj/medical/surgery_tools.dmi', "cautery"),
+		TOOL_DRILL = uni_icon('icons/obj/medical/surgery_tools.dmi', "drill"),
+		TOOL_SCALPEL = uni_icon('icons/obj/medical/surgery_tools.dmi', "scalpel"),
+		TOOL_SAW = uni_icon('icons/obj/medical/surgery_tools.dmi', "saw"),
+		TOOL_BONESET = uni_icon('icons/obj/medical/surgery_tools.dmi', "bonesetter"),
+		TOOL_KNIFE = uni_icon('icons/obj/service/kitchen.dmi', "knife"),
+		TOOL_BLOODFILTER = uni_icon('icons/obj/medical/surgery_tools.dmi', "bloodfilter"),
+		TOOL_ROLLINGPIN = uni_icon('icons/obj/service/kitchen.dmi', "rolling_pin"),
+		TOOL_RUSTSCRAPER = uni_icon('icons/obj/tools.dmi', "wirebrush"),
 	)
 
 	for(var/tool in tool_icons)
-		Insert(replacetext(tool, " ", ""), tool_icons[tool])
+		insert_icon(replacetext(tool, " ", ""), tool_icons[tool])

code/modules/asset_cache/assets/emojipedia.dm

@@ -1,5 +1,5 @@
-/datum/asset/spritesheet/emojipedia
+/datum/asset/spritesheet_batched/emojipedia
 	name = "emojipedia"
 
-/datum/asset/spritesheet/emojipedia/create_spritesheets()
-	InsertAll("", EMOJI_SET)
+/datum/asset/spritesheet_batched/emojipedia/create_spritesheets()
+	insert_all_icons("", EMOJI_SET)

code/modules/asset_cache/assets/fish.dm

@@ -1,14 +1,13 @@
-/datum/asset/spritesheet/fish
+/datum/asset/spritesheet_batched/fish
 	name = "fish"
 
-/datum/asset/spritesheet/fish/create_spritesheets()
+/datum/asset/spritesheet_batched/fish/create_spritesheets()
 	var/list/id_list = list()
-	for (var/path in subtypesof(/obj/item/fish))
-		var/obj/item/fish/fish_type = path
+	for (var/obj/item/fish/fish_type as anything in subtypesof(/obj/item/fish))
 		var/fish_icon = initial(fish_type.icon)
 		var/fish_icon_state = initial(fish_type.icon_state)
 		var/id = sanitize_css_class_name("[fish_icon][fish_icon_state]")
 		if(id in id_list) //no dupes
 			continue
 		id_list += id
-		Insert(id, fish_icon, fish_icon_state)
+		insert_icon(id, uni_icon(fish_icon, fish_icon_state))

code/modules/asset_cache/assets/light_templates.dm

@@ -1,11 +1,7 @@
-/datum/asset/spritesheet/lights
+/datum/asset/spritesheet_batched/lights
 	name = "lights"
 
-/datum/asset/spritesheet/lights/create_spritesheets()
-	// These two are required to ensure this spritesheet is not rendered with a fully white background
-	// No I have absolutely no idea why, something something alpha maybe? but it does work, so that's for LATER!!
-	Insert("light_dummy_start_fuckyoubyond", 'icons/obj/medical/bloodpack.dmi', "generic_bloodpack")
+/datum/asset/spritesheet_batched/lights/create_spritesheets()
 	for(var/id in GLOB.light_types)
 		var/datum/light_template/template = GLOB.light_types[id]
-		Insert("light_fantastic_[template.id]", template.icon, template.icon_state)
-	Insert("light_dummy_end_fuckyoubyond", 'icons/mob/silicon/ai.dmi', "questionmark")
+		insert_icon("light_fantastic_[template.id]", uni_icon(template.icon, template.icon_state))

code/modules/asset_cache/assets/mafia.dm

@@ -1,5 +1,5 @@
-/datum/asset/spritesheet/mafia
+/datum/asset/spritesheet_batched/mafia
 	name = "mafia"
 
-/datum/asset/spritesheet/mafia/create_spritesheets()
-	InsertAll("", 'icons/obj/mafia.dmi')
+/datum/asset/spritesheet_batched/mafia/create_spritesheets()
+	insert_all_icons("", 'icons/obj/mafia.dmi')

code/modules/asset_cache/assets/mecha.dm

@@ -1,6 +1,6 @@
-/datum/asset/spritesheet/mecha_equipment
+/datum/asset/spritesheet_batched/mecha_equipment
 	name = "mecha_equipment"
 
-/datum/asset/spritesheet/mecha_equipment/create_spritesheets()
-	InsertAll("", 'icons/obj/devices/mecha_equipment.dmi')
-	InsertAll("", 'icons/obj/ore.dmi')
+/datum/asset/spritesheet_batched/mecha_equipment/create_spritesheets()
+	insert_all_icons("", 'icons/obj/devices/mecha_equipment.dmi')
+	insert_all_icons("", 'icons/obj/ore.dmi')

code/modules/asset_cache/assets/moods.dm

@@ -1,27 +1,18 @@
-/datum/asset/spritesheet/moods
+/datum/asset/spritesheet_batched/moods
 	name = "moods"
-	var/iconinserted = 1
 
-/datum/asset/spritesheet/moods/create_spritesheets()
-	for(var/i in 1 to 9)
-		var/target_to_insert = "mood"+"[iconinserted]"
-		Insert(target_to_insert, 'icons/hud/screen_gen.dmi', target_to_insert)
-		iconinserted++
-
-/datum/asset/spritesheet/moods/ModifyInserted(icon/pre_asset)
-	var/blended_color
-	switch(iconinserted)
-		if(1)
-			blended_color = "#f15d36"
-		if(2 to 3)
-			blended_color = "#f38943"
-		if(4)
-			blended_color = "#dfa65b"
-		if(5)
-			blended_color = "#4b96c4"
-		if(6)
-			blended_color = "#86d656"
-		else
-			blended_color = "#2eeb9a"
-	pre_asset.Blend(blended_color, ICON_MULTIPLY)
-	return pre_asset
+/datum/asset/spritesheet_batched/moods/create_spritesheets()
+	var/list/mood_colors = list(
+		"mood1" = "#f15d36",
+		"mood2" = "#f38943",
+		"mood3" = "#f38943",
+		"mood4" = "#dfa65b",
+		"mood5" = "#4b96c4",
+		"mood6" = "#86d656",
+		"mood7" = "#2eeb9a",
+		"mood8" = "#2eeb9a",
+		"mood9" = "#2eeb9a",
+	)
+	for(var/target_to_insert in mood_colors)
+		var/blended_color = mood_colors[target_to_insert]
+		insert_icon(target_to_insert, uni_icon('icons/hud/screen_gen.dmi', target_to_insert, color=blended_color))

code/modules/asset_cache/assets/pda.dm

@@ -1,34 +0,0 @@
-/datum/asset/spritesheet/simple/pda
-	name = "pda"
-	assets = list(
-		"atmos" = 'icons/ui/pda/pda_atmos.png',
-		"back" = 'icons/ui/pda/pda_back.png',
-		"bell" = 'icons/ui/pda/pda_bell.png',
-		"blank" = 'icons/ui/pda/pda_blank.png',
-		"boom" = 'icons/ui/pda/pda_boom.png',
-		"bucket" = 'icons/ui/pda/pda_bucket.png',
-		"medbot" = 'icons/ui/pda/pda_medbot.png',
-		"floorbot" = 'icons/ui/pda/pda_floorbot.png',
-		"cleanbot" = 'icons/ui/pda/pda_cleanbot.png',
-		"crate" = 'icons/ui/pda/pda_crate.png',
-		"cuffs" = 'icons/ui/pda/pda_cuffs.png',
-		"eject" = 'icons/ui/pda/pda_eject.png',
-		"flashlight" = 'icons/ui/pda/pda_flashlight.png',
-		"honk" = 'icons/ui/pda/pda_honk.png',
-		"mail" = 'icons/ui/pda/pda_mail.png',
-		"medical" = 'icons/ui/pda/pda_medical.png',
-		"menu" = 'icons/ui/pda/pda_menu.png',
-		"mule" = 'icons/ui/pda/pda_mule.png',
-		"notes" = 'icons/ui/pda/pda_notes.png',
-		"power" = 'icons/ui/pda/pda_power.png',
-		"rdoor" = 'icons/ui/pda/pda_rdoor.png',
-		"reagent" = 'icons/ui/pda/pda_reagent.png',
-		"refresh" = 'icons/ui/pda/pda_refresh.png',
-		"scanner" = 'icons/ui/pda/pda_scanner.png',
-		"signaler" = 'icons/ui/pda/pda_signaler.png',
-		"skills" = 'icons/ui/pda/pda_skills.png',
-		"status" = 'icons/ui/pda/pda_status.png',
-		"dronephone" = 'icons/ui/pda/pda_dronephone.png',
-		"emoji" = 'icons/ui/pda/pda_emoji.png',
-		"droneblacklist" = 'icons/ui/pda/pda_droneblacklist.png',
-	)

code/modules/asset_cache/assets/pipes.dm

@@ -1,6 +1,7 @@
-/datum/asset/spritesheet/pipes
+/datum/asset/spritesheet_batched/pipes
 	name = "pipes"
+	ignore_dir_errors = TRUE
 
-/datum/asset/spritesheet/pipes/create_spritesheets()
+/datum/asset/spritesheet_batched/pipes/create_spritesheets()
 	for (var/each in list('icons/obj/pipes_n_cables/pipe_item.dmi', 'icons/obj/pipes_n_cables/disposal.dmi', 'icons/obj/pipes_n_cables/transit_tube.dmi', 'icons/obj/pipes_n_cables/hydrochem/fluid_ducts.dmi'))
-		InsertAll("", each, GLOB.alldirs)
+		insert_all_icons("", each, GLOB.alldirs)

code/modules/asset_cache/assets/plumbing.dm

@@ -1,7 +1,7 @@
-/datum/asset/spritesheet/plumbing
+/datum/asset/spritesheet_batched/plumbing
 	name = "plumbing-tgui"
 
-/datum/asset/spritesheet/plumbing/create_spritesheets()
+/datum/asset/spritesheet_batched/plumbing/create_spritesheets()
 	//load only what we need from the icon files,format is icon_file_name = list of icon_states we need from this file
 	var/list/essentials = list(
 		'icons/obj/medical/iv_drip.dmi' = list("plumb"),
@@ -39,5 +39,5 @@
 
 	for(var/icon_file as anything in essentials)
 		for(var/icon_state as anything in essentials[icon_file])
-			Insert(sprite_name = icon_state, I = icon_file, icon_state = icon_state)
+			insert_icon(icon_state, uni_icon(icon_file, icon_state))
 

code/modules/asset_cache/assets/rcd.dm

@@ -1,7 +1,7 @@
-/datum/asset/spritesheet/rcd
+/datum/asset/spritesheet_batched/rcd
 	name = "rcd-tgui"
 
-/datum/asset/spritesheet/rcd/create_spritesheets()
+/datum/asset/spritesheet_batched/rcd/create_spritesheets()
 	for(var/root_category in GLOB.rcd_designs)
 
 		var/list/category_designs = GLOB.rcd_designs[root_category]
@@ -12,34 +12,35 @@
 			var/list/designs = category_designs[category]
 
 			var/sprite_name
-			var/icon/sprite_icon
+
 			for(var/list/design as anything in designs)
 				var/atom/movable/path = design[RCD_DESIGN_PATH]
 				if(!ispath(path))
 					continue
 				sprite_name = initial(path.name)
+				var/datum/universal_icon/sprite_icon
 
 				//icon for windows are blended with grills if required and loaded from radial menu
 				if(ispath(path, /obj/structure/window))
 					if(path == /obj/structure/window)
-						sprite_icon = icon(icon = 'icons/hud/radial.dmi', icon_state = "windowsize")
+						sprite_icon = uni_icon('icons/hud/radial.dmi', "windowsize")
 					else if(path == /obj/structure/window/reinforced)
-						sprite_icon = icon(icon = 'icons/hud/radial.dmi', icon_state = "windowtype")
+						sprite_icon = uni_icon('icons/hud/radial.dmi', "windowtype")
 					else if(path == /obj/structure/window/fulltile || path == /obj/structure/window/reinforced/fulltile)
-						sprite_icon = icon(icon = initial(path.icon), icon_state = initial(path.icon_state))
-						sprite_icon.Blend(icon(icon = 'icons/obj/structures.dmi', icon_state = "grille"), ICON_UNDERLAY)
+						sprite_icon = uni_icon(initial(path.icon), initial(path.icon_state))
+						sprite_icon.blend_icon(uni_icon('icons/obj/structures.dmi', "grille"), ICON_UNDERLAY)
 
 				//icons for solid airlocks have an added solid overlay on top of their glass icons
 				else if(ispath(path, /obj/machinery/door/airlock))
 					var/obj/machinery/door/airlock/airlock_path = path
 					var/airlock_icon = initial(airlock_path.icon)
 
-					sprite_icon = icon(icon = airlock_icon, icon_state = "closed")
-					if(!initial(airlock_path.glass))
-						sprite_icon.Blend(icon(icon = airlock_icon, icon_state = "fill_closed"), ICON_OVERLAY)
+					sprite_icon = uni_icon(airlock_icon, "closed")
+					if(!initial(airlock_path.glass) && initial(airlock_path.can_be_glass))
+						sprite_icon.blend_icon(uni_icon(airlock_icon, "fill_closed"), ICON_OVERLAY)
 
 				//for all other icons we load the paths default icon & icon state
 				else
-					sprite_icon = icon(icon = initial(path.icon), icon_state = initial(path.icon_state))
+					sprite_icon = uni_icon(initial(path.icon), initial(path.icon_state))
 
-				Insert(sanitize_css_class_name(sprite_name), sprite_icon)
+				insert_icon(sanitize_css_class_name(sprite_name), sprite_icon)

code/modules/asset_cache/assets/research_designs.dm

@@ -1,15 +1,15 @@
 // Representative icons for each research design
-/datum/asset/spritesheet/research_designs
+/datum/asset/spritesheet_batched/research_designs
 	name = "design"
 
-/datum/asset/spritesheet/research_designs/create_spritesheets()
+/datum/asset/spritesheet_batched/research_designs/create_spritesheets()
 	for (var/datum/design/path as anything in subtypesof(/datum/design))
 		if(initial(path.id) == DESIGN_ID_IGNORE)
 			continue
 
 		var/icon_file
 		var/icon_state
-		var/icon/I
+		var/datum/icon_transformer/transform = null
 
 		if(initial(path.research_icon) && initial(path.research_icon_state)) //If the design has an icon replacement skip the rest
 			icon_file = initial(path.research_icon)
@@ -18,8 +18,6 @@
 				if(!icon_exists(icon_file, icon_state))
 					stack_trace("design [path] with icon '[icon_file]' missing state '[icon_state]'")
 					continue
-			I = icon(icon_file, icon_state, SOUTH)
-
 		else
 			// construct the icon and slap it into the resource cache
 			var/atom/item = initial(path.build_path)
@@ -38,30 +36,32 @@
 				if (machine)
 					item = machine
 
-			// Check for GAGS support where necessary
-			var/greyscale_config = initial(item.greyscale_config)
-			var/greyscale_colors = initial(item.greyscale_colors)
-			if (greyscale_config && greyscale_colors)
-				icon_file = SSgreyscale.GetColoredIconByType(greyscale_config, greyscale_colors)
+			// GAGS icon short-circuit the rest of the checks
+			if (initial(item.greyscale_config) && initial(item.greyscale_colors))
+				insert_icon(initial(path.id), gags_to_universal_icon(item))
+				continue
 			else
 				icon_file = initial(item.icon)
 
 			icon_state = initial(item.icon_state)
+			if(initial(item.color))
+				transform = color_transform(initial(item.color))
 			if (PERFORM_ALL_TESTS(focus_only/invalid_research_designs))
 				if(!icon_exists(icon_file, icon_state))
 					stack_trace("design [path] with icon '[icon_file]' missing state '[icon_state]'")
 					continue
-			I = icon(icon_file, icon_state, SOUTH)
 
 			// computers (and snowflakes) get their screen and keyboard sprites
 			if (ispath(item, /obj/machinery/computer) || ispath(item, /obj/machinery/power/solar_control))
+				if(!transform)
+					transform = new()
 				var/obj/machinery/computer/C = item
 				var/screen = initial(C.icon_screen)
 				var/keyboard = initial(C.icon_keyboard)
 				var/all_states = icon_states(icon_file)
 				if (screen && (screen in all_states))
-					I.Blend(icon(icon_file, screen, SOUTH), ICON_OVERLAY)
+					transform.blend_icon(uni_icon(icon_file, screen), ICON_OVERLAY)
 				if (keyboard && (keyboard in all_states))
-					I.Blend(icon(icon_file, keyboard, SOUTH), ICON_OVERLAY)
+					transform.blend_icon(uni_icon(icon_file, keyboard), ICON_OVERLAY)
 
-		Insert(initial(path.id), I)
+		insert_icon(initial(path.id), uni_icon(icon_file, icon_state, transform=transform))

code/modules/asset_cache/assets/rtd.dm

@@ -1,14 +1,12 @@
-/datum/asset/spritesheet/rtd
+/datum/asset/spritesheet_batched/rtd
 	name = "rtd"
 
-/datum/asset/spritesheet/rtd/create_spritesheets()
-	//some tiles may share the same icon but have different properties to animate that icon
-	//so we keep track of what icons we registered
+/datum/asset/spritesheet_batched/rtd/create_spritesheets()
 	var/list/registered = list()
 
 	for(var/main_root in GLOB.floor_designs)
 		for(var/sub_category in GLOB.floor_designs[main_root])
-			for(var/list/design in  GLOB.floor_designs[main_root][sub_category])
+			for(var/list/design in GLOB.floor_designs[main_root][sub_category])
 				if(!design["datum"])
 					populate_rtd_datums()
 				var/datum/tile_info/tile_data = design["datum"]
@@ -17,5 +15,5 @@
 					var/sprite_name = sanitize_css_class_name("[tile_data.icon_file]-[tile_data.icon_state]-[dir2text(direction)]")
 					if(registered[sprite_name])
 						continue
-					Insert(sprite_name, icon(tile_data.icon_file, tile_data.icon_state, direction))
+					insert_icon(sprite_name, uni_icon(tile_data.icon_file, tile_data.icon_state, direction))
 					registered[sprite_name] = TRUE

code/modules/asset_cache/assets/seeds.dm

@@ -1,14 +1,13 @@
-/datum/asset/spritesheet/seeds
+/datum/asset/spritesheet_batched/seeds
 	name = "seeds"
 
-/datum/asset/spritesheet/seeds/create_spritesheets()
+/datum/asset/spritesheet_batched/seeds/create_spritesheets()
 	var/list/id_list = list()
-	for (var/path in subtypesof(/obj/item/seeds))
-		var/obj/item/seeds/seed_type = path
+	for (var/obj/item/seeds/seed_type as anything in subtypesof(/obj/item/seeds))
 		var/icon = initial(seed_type.icon)
 		var/icon_state = initial(seed_type.icon_state)
 		var/id = sanitize_css_class_name("[icon][icon_state]")
 		if(id in id_list) //no dupes
 			continue
 		id_list += id
-		Insert(id, icon, icon_state)
+		insert_icon(id, uni_icon(icon, icon_state))

code/modules/asset_cache/assets/sheetmaterials.dm

@@ -1,6 +1,6 @@
-/datum/asset/spritesheet/sheetmaterials
+/datum/asset/spritesheet_batched/sheetmaterials
 	name = "sheetmaterials"
 
-/datum/asset/spritesheet/sheetmaterials/create_spritesheets()
-	InsertAll("", 'icons/obj/stack_objects.dmi')
+/datum/asset/spritesheet_batched/sheetmaterials/create_spritesheets()
+	insert_all_icons("", 'icons/obj/stack_objects.dmi')
 

code/modules/asset_cache/assets/supplypods.dm

@@ -1,27 +1,27 @@
-/datum/asset/spritesheet/supplypods
+/datum/asset/spritesheet_batched/supplypods
 	name = "supplypods"
 
-/datum/asset/spritesheet/supplypods/create_spritesheets()
+/datum/asset/spritesheet_batched/supplypods/create_spritesheets()
 	for (var/datum/pod_style/style as anything in typesof(/datum/pod_style))
 		if (ispath(style, /datum/pod_style/seethrough))
-			Insert("pod_asset[style::id]", icon('icons/obj/supplypods.dmi' , "seethrough-icon"))
+			insert_icon("pod_asset[style::id]", uni_icon('icons/obj/supplypods.dmi' , "seethrough-icon"))
 			continue
 		var/base = style::icon_state
 		if (!base)
-			Insert("pod_asset[style::id]", icon('icons/obj/supplypods.dmi', "invisible-icon"))
+			insert_icon("pod_asset[style::id]", uni_icon('icons/obj/supplypods.dmi', "invisible-icon"))
 			continue
-		var/icon/podIcon = icon('icons/obj/supplypods.dmi', base)
+		var/datum/universal_icon/pod_icon = uni_icon('icons/obj/supplypods.dmi', base, SOUTH)
 		var/door = style::has_door
 		if (door)
 			door = "[base]_door"
-			podIcon.Blend(icon('icons/obj/supplypods.dmi', door), ICON_OVERLAY)
+			pod_icon.blend_icon(uni_icon('icons/obj/supplypods.dmi', door), ICON_OVERLAY)
 		var/shape = style::shape
 		if (shape == POD_SHAPE_NORMAL)
 			var/decal = style::decal_icon
 			if (decal)
-				podIcon.Blend(icon('icons/obj/supplypods.dmi', decal), ICON_OVERLAY)
+				pod_icon.blend_icon(uni_icon('icons/obj/supplypods.dmi', decal), ICON_OVERLAY)
 			var/glow = style::glow_color
 			if (glow)
 				glow = "pod_glow_[glow]"
-				podIcon.Blend(icon('icons/obj/supplypods.dmi', glow), ICON_OVERLAY)
-		Insert("pod_asset[style::id]", podIcon)
+				pod_icon.blend_icon(uni_icon('icons/obj/supplypods.dmi', glow), ICON_OVERLAY)
+		insert_icon("pod_asset[style::id]", pod_icon)

code/modules/asset_cache/assets/tcomms.dm

@@ -1,12 +1,12 @@
-/datum/asset/spritesheet/telecomms
+/datum/asset/spritesheet_batched/telecomms
 	name = "tcomms"
 
-/datum/asset/spritesheet/telecomms/create_spritesheets()
+/datum/asset/spritesheet_batched/telecomms/create_spritesheets()
 	var/list/inserted_states = list() // No need to send entire `telecomms.dmi`.
 	for(var/obj/machinery/telecomms/machine as anything in subtypesof(/obj/machinery/telecomms))
 		var/icon_state = machine::icon_state
 		if(icon_state in inserted_states)
 			continue
 
-		Insert(icon_state, machine::icon, icon_state)
+		insert_icon(icon_state, uni_icon(machine::icon, icon_state))
 		inserted_states += icon_state

code/modules/asset_cache/assets/vending.dm

@@ -1,10 +1,10 @@
-/datum/asset/spritesheet/vending
+/datum/asset/spritesheet_batched/vending
 	name = "vending"
 
-/datum/asset/spritesheet/vending/create_spritesheets()
+/datum/asset/spritesheet_batched/vending/create_spritesheets()
 	// initialising the list of items we need
 	var/target_items = list()
-	for(var/obj/machinery/vending/vendor as anything in typesof(/obj/machinery/vending))
+	for(var/obj/machinery/vending/vendor as anything in subtypesof(/obj/machinery/vending))
 		vendor = new vendor() // It seems `initial(list var)` has nothing. need to make a type.
 		target_items |= vendor.products
 		target_items |= vendor.premium
@@ -16,21 +16,21 @@
 		if (!ispath(item, /atom))
 			continue
 
-		var/icon_file
 		var/icon_state = initial(item.icon_state)
-		var/icon_color = initial(item.color)
-		// GAGS icons must be pregenerated
-		if(initial(item.greyscale_config) && initial(item.greyscale_colors))
-			icon_file = SSgreyscale.GetColoredIconByType(initial(item.greyscale_config), initial(item.greyscale_colors))
-		// Colored atoms must be pregenerated
-		else if(icon_color && icon_state)
-			icon_file = initial(item.icon)
+		if(ispath(item, /obj))
+			var/obj/obj_atom = item
+			if(initial(obj_atom.icon_state_preview))
+				icon_state = initial(obj_atom.icon_state_preview)
+		var/has_gags = initial(item.greyscale_config) && initial(item.greyscale_colors)
+		var/has_color = initial(item.color) && icon_state
+		// GAGS and colored icons must be pregenerated
 		// Otherwise we can rely on DMIcon, so skip it to save init time
-		else
+		if(!has_gags && !has_color)
 			continue
 
 		if (PERFORM_ALL_TESTS(focus_only/invalid_vending_machine_icon_states))
-			if (!icon_exists(icon_file, icon_state))
+			if (!has_gags && !icon_exists(initial(item.icon), icon_state))
+				var/icon_file = initial(item.icon)
 				var/icon_states_string
 				for (var/an_icon_state in icon_states(icon_file))
 					if (!icon_states_string)
@@ -41,10 +41,5 @@
 				stack_trace("[item] does not have a valid icon state, icon=[icon_file], icon_state=[json_encode(icon_state)]([text_ref(icon_state)]), icon_states=[icon_states_string]")
 				continue
 
-		var/icon/produced = icon(icon_file, icon_state, SOUTH)
-		if (!isnull(icon_color) && icon_color != COLOR_WHITE)
-			produced.Blend(icon_color, ICON_MULTIPLY)
-
 		var/imgid = replacetext(replacetext("[item]", "/obj/item/", ""), "/", "-")
-
-		Insert(imgid, produced)
+		insert_icon(imgid, get_display_icon_for(item))

code/modules/asset_cache/spritesheet/batched/batched_spritesheet.dm

@@ -0,0 +1,365 @@
+#define SPR_SIZE "size_id"
+#define SPR_IDX "position"
+#define CACHE_WAIT "wait"
+#define CACHE_INVALID TRUE
+#define CACHE_VALID FALSE
+/// This is used to invalidate the cache if something changes on the DM side. For example, if the CSS generator was changed.
+#define SPRITESHEET_SYSTEM_VERSION 1
+
+/datum/asset/spritesheet_batched
+	_abstract = /datum/asset/spritesheet_batched
+	var/name
+	/// list("32x32")
+	var/list/sizes = list()
+	/// "foo_bar" -> list("32x32", 5, entry_obj)
+	var/list/sprites = list()
+
+	// "foo_bar" -> entry_obj
+	var/list/entries = list()
+
+	/// JSON encoded version of entries.
+	var/entries_json = null
+
+	/// If this spritesheet exists in a completed state.
+	var/fully_generated = FALSE
+
+	/// If this asset should be fully loaded on new
+	/// Defaults to false so we can process this stuff nicely
+	var/load_immediately = FALSE
+	/// If we should avoid propogating 'invalid dir' errors from rust-g. Because sometimes, you just don't know what dirs are valid.
+	var/ignore_dir_errors = FALSE
+
+	/// Forces use of the smart cache. This is for unit tests, please respect the config <3
+	var/force_cache = FALSE
+
+	/// If there is currently an async job, its ID
+	var/job_id = null
+	/// If there is currently an async cache job, its ID.
+	var/cache_job_id = null
+
+	// Fields to store async cache task inputs.
+	var/cache_data = null
+	var/cache_sizes_data = null
+	var/cache_sprites_data = null
+	var/cache_input_hash = null
+	var/cache_dmi_hashes = null
+	var/cache_dmi_hashes_json = null
+	/// Used to prevent async cache refresh jobs from looping on failure.
+	var/cache_result = null
+
+/datum/asset/spritesheet_batched/proc/should_load_immediately()
+#ifdef DO_NOT_DEFER_ASSETS
+	return TRUE
+#else
+	return load_immediately
+#endif
+
+/// Returns true if the cache should be invalidated/doesn't exist.
+/datum/asset/spritesheet_batched/should_refresh(yield)
+	. = CACHE_INVALID // in the case of any errors, we need to regenerate.
+	if(!fexists("[ASSET_CROSS_ROUND_SMART_CACHE_DIRECTORY]/spritesheet_cache.[name].json"))
+		return CACHE_INVALID
+	if(!fexists("data/spritesheets/spritesheet_[name].css"))
+		return CACHE_INVALID
+	if(isnull(cache_data) || isnull(cache_dmi_hashes_json))
+		cache_data = rustg_file_read("[ASSET_CROSS_ROUND_SMART_CACHE_DIRECTORY]/spritesheet_cache.[name].json")
+		if(!findtext(cache_data, "{", 1, 2)) // cache isn't valid JSON
+			log_asset("Cache for spritesheet_[name] was not valid JSON. This is abnormal. Likely tampered with or IO failure.")
+			return CACHE_INVALID
+		var/cache_json = json_decode(cache_data)
+		// Best to invalidate if rustg updates, since the way icons are handled can change.
+		var/cached_rustg_version = cache_json["rustg_version"]
+		if(isnull(cached_rustg_version))
+			log_asset("Cache for spritesheet_[name] did not contain a rustg_version!")
+			return CACHE_INVALID
+		var/rustg_version = rustg_get_version()
+		if(cached_rustg_version != rustg_version)
+			log_asset("Invalidated cache for spritesheet_[name] due to rustg updating from [cached_rustg_version] to [rustg_version].")
+			return CACHE_INVALID
+				// Invalidate cache if the DM version changes
+		var/cached_dm_version = cache_json["dm_version"]
+		if(isnull(cached_dm_version))
+			log_asset("Cache for spritesheet_[name] did not contain a dm_version!")
+			return CACHE_INVALID
+		if(cached_dm_version != SPRITESHEET_SYSTEM_VERSION)
+			log_asset("Invalidated cache for spritesheet_[name] due to DM spritesheet system updating from [cached_dm_version] to [SPRITESHEET_SYSTEM_VERSION].")
+			return CACHE_INVALID
+		cache_sizes_data = cache_json["sizes"]
+		cache_sprites_data = cache_json["sprites"]
+		cache_input_hash = cache_json["input_hash"]
+		cache_dmi_hashes = cache_json["dmi_hashes"]
+		if(!length(cache_dmi_hashes) || !length(cache_input_hash) || !length(cache_sizes_data) || !length(cache_sprites_data))
+			log_asset("Cache for spritesheet_[name] did not contain the correct data. This is abnormal. Likely tampered with.")
+			return CACHE_INVALID
+		cache_dmi_hashes_json = json_encode(cache_dmi_hashes)
+	var/data_out
+
+	if(yield || !isnull(cache_job_id))
+		if(isnull(cache_job_id))
+			cache_job_id = rustg_iconforge_cache_valid_async(cache_input_hash, cache_dmi_hashes_json, entries_json)
+		. = CACHE_WAIT // if we return during this, WAIT!!
+		UNTIL((data_out = rustg_iconforge_check(cache_job_id)) != RUSTG_JOB_NO_RESULTS_YET)
+		cache_job_id = null
+		. = CACHE_INVALID // reset back to normal, invalid on CRASH
+	else
+		data_out = rustg_iconforge_cache_valid(cache_input_hash, cache_dmi_hashes_json, entries_json)
+	if (data_out == RUSTG_JOB_ERROR)
+		CRASH("Spritesheet [name] cache JOB PANIC")
+	else if(!findtext(data_out, "{", 1, 2))
+		rustg_file_write(cache_data, "[GLOB.log_directory]/spritesheet_cache_debug.[name].json")
+		rustg_file_write(entries_json, "[GLOB.log_directory]/spritesheet_debug_[name].json")
+		CRASH("Spritesheet [name] cache check UNKNOWN ERROR: [data_out]")
+	var/result = json_decode(data_out)
+	var/fail = result["fail_reason"]
+	if(length(fail) || result["result"] != "1")
+		if(findtextEx(fail, "ERROR:"))
+			CRASH("Spritesheet [name] cache check UNKNOWN [fail]")
+		log_asset("Invalidated cache for spritesheet_[name]: [fail]")
+		return CACHE_INVALID
+	// Populate the sizes and sprites list.
+	sizes = cache_sizes_data
+	sprites = cache_sprites_data
+	log_asset("Validated cache for spritesheet_[name]!")
+	return CACHE_VALID
+
+/datum/asset/spritesheet_batched/proc/insert_icon(sprite_name, datum/universal_icon/entry)
+	if(!istext(sprite_name) || !length(sprite_name))
+		CRASH("Invalid sprite_name \"[sprite_name]\" given to insert_icon()! Providing non-strings will break icon generation.")
+	if(!istype(entry))
+		CRASH("Invalid type provided to insert_icon()! Value: [entry] (type: [entry?.type])")
+	entries[sprite_name] = entry.to_list()
+
+/datum/asset/spritesheet_batched/register()
+	SHOULD_NOT_OVERRIDE(TRUE)
+
+	if (!name)
+		CRASH("spritesheet [type] cannot register without a name")
+
+	// Create our input data first, so we can compare to the cache.
+	create_spritesheets()
+
+	if(should_load_immediately())
+		realize_spritesheets(yield = FALSE)
+	else
+		SSasset_loading.queue_asset(src)
+
+/datum/asset/spritesheet_batched/unregister()
+	CRASH("unregister() called on batched spritesheet! Bad!")
+
+/// Call insert_icon or insert_all_icons here, building a spritesheet!
+/datum/asset/spritesheet_batched/proc/create_spritesheets()
+	CRASH("create_spritesheets() not implemented for [type]!")
+
+/datum/asset/spritesheet_batched/proc/insert_all_icons(prefix, icon/I, list/directions, prefix_with_dirs = TRUE)
+	if (length(prefix))
+		prefix = "[prefix]-"
+
+	if (!directions)
+		directions = list(SOUTH)
+
+	for (var/icon_state_name in icon_states(I))
+		for (var/direction in directions)
+			var/prefix2 = (directions.len > 1 && prefix_with_dirs) ? "[dir2text(direction)]-" : ""
+			insert_icon("[prefix][prefix2][icon_state_name]", uni_icon(I, icon_state_name, direction))
+
+/datum/asset/spritesheet_batched/proc/realize_spritesheets(yield)
+	if(fully_generated)
+		return
+	if(!length(entries))
+		CRASH("Spritesheet [name] ([type]) is empty! What are you doing?")
+
+	if(isnull(entries_json))
+		entries_json = json_encode(entries)
+
+	if(isnull(cache_result))
+		cache_result = should_refresh(yield)
+		if(cache_result == CACHE_WAIT) // sleep interrupted by MC. We'll get queried again later.
+			cache_result = null
+			return
+
+	// read_from_cache returns false if config is disabled, otherwise it fully loads the spritesheet.
+	if (cache_result == CACHE_VALID && read_from_cache())
+		SSasset_loading.dequeue_asset(src)
+		fully_generated = TRUE
+		return
+	// Remove the cache, since it's invalid if we get to this point.
+	fdel("[ASSET_CROSS_ROUND_SMART_CACHE_DIRECTORY]/spritesheet_cache.[name].json")
+
+	var/do_cache = CONFIG_GET(flag/smart_cache_assets) || force_cache
+	var/data_out
+	if(yield || !isnull(job_id))
+		if(isnull(job_id))
+			job_id = rustg_iconforge_generate_async("data/spritesheets/", name, entries_json, do_cache)
+		UNTIL((data_out = rustg_iconforge_check(job_id)) != RUSTG_JOB_NO_RESULTS_YET)
+	else
+		data_out = rustg_iconforge_generate("data/spritesheets/", name, entries_json, do_cache)
+	if (data_out == RUSTG_JOB_ERROR)
+		CRASH("Spritesheet [name] JOB PANIC")
+	else if(!findtext(data_out, "{", 1, 2))
+		rustg_file_write(entries_json, "[GLOB.log_directory]/spritesheet_debug_[name].json")
+		CRASH("Spritesheet [name] UNKNOWN ERROR: [data_out]")
+	var/data = json_decode(data_out)
+	sizes = data["sizes"]
+	sprites = data["sprites"]
+	var/input_hash = data["sprites_hash"]
+	var/dmi_hashes = data["dmi_hashes"] // this only contains values if do_cache is TRUE.
+
+	for(var/size_id in sizes)
+		var/png_name = "[name]_[size_id].png"
+		var/file_directory = "data/spritesheets/[png_name]"
+		var/file_hash = rustg_hash_file(RUSTG_HASH_MD5, file_directory)
+		SSassets.transport.register_asset(png_name, fcopy_rsc(file_directory), file_hash)
+		if(CONFIG_GET(flag/save_spritesheets))
+			save_to_logs(file_name = png_name, file_location = file_directory)
+	var/css_name = "spritesheet_[name].css"
+	var/file_directory = "data/spritesheets/[css_name]"
+
+	fdel(file_directory)
+	var/css = generate_css()
+	rustg_file_write(css, file_directory)
+	var/css_hash = rustg_hash_string(RUSTG_HASH_MD5, css)
+	SSassets.transport.register_asset(css_name, fcopy_rsc(file_directory), file_hash=css_hash)
+
+	if(CONFIG_GET(flag/save_spritesheets))
+		save_to_logs(file_name = css_name, file_location = file_directory)
+
+	if (do_cache)
+		write_cache_meta(input_hash, dmi_hashes)
+	fully_generated = TRUE
+	// If we were ever in there, remove ourselves
+	SSasset_loading.dequeue_asset(src)
+	if(data["error"] && !(ignore_dir_errors && findtext(data["error"], "is not in the set of valid dirs")))
+		CRASH("Error during spritesheet generation for [name]: [data["error"]]")
+
+/datum/asset/spritesheet_batched/queued_generation()
+	realize_spritesheets(yield = TRUE)
+
+/datum/asset/spritesheet_batched/ensure_ready()
+	if(!fully_generated)
+		realize_spritesheets(yield = FALSE)
+	return ..()
+
+/datum/asset/spritesheet_batched/send(client/client)
+	if (!name)
+		return
+
+	var/all = list("spritesheet_[name].css")
+	for(var/size_id in sizes)
+		all += "[name]_[size_id].png"
+	. = SSassets.transport.send_assets(client, all)
+
+/datum/asset/spritesheet_batched/get_url_mappings()
+	if (!name)
+		return
+
+	. = list("spritesheet_[name].css" = SSassets.transport.get_asset_url("spritesheet_[name].css"))
+	for(var/size_id in sizes)
+		.["[name]_[size_id].png"] = SSassets.transport.get_asset_url("[name]_[size_id].png")
+
+/datum/asset/spritesheet_batched/proc/generate_css()
+	var/list/out = list()
+
+	for (var/size_id in sizes)
+		var/size_split = splittext(size_id, "x")
+		var/width = text2num(size_split[1])
+		var/height = text2num(size_split[2])
+		out += ".[name][size_id]{display:inline-block;width:[width]px;height:[height]px;background-image:url('[get_background_url("[name]_[size_id].png")]');background-repeat:no-repeat;}"
+
+	for (var/sprite_id in sprites)
+		var/sprite = sprites[sprite_id]
+		var/size_id = sprite[SPR_SIZE]
+		var/idx = sprite[SPR_IDX]
+
+		var/size_split = splittext(size_id, "x")
+		var/width = text2num(size_split[1])
+		var/x = idx * width
+		var/y = 0
+
+		out += ".[name][size_id].[sprite_id]{background-position:-[x]px -[y]px;}"
+
+	return out.Join("\n")
+
+/datum/asset/spritesheet_batched/proc/read_from_cache()
+	if(!CONFIG_GET(flag/smart_cache_assets) && !force_cache)
+		return FALSE
+	// this is already guaranteed to exist.
+	var/css_name = "spritesheet_[name].css"
+	var/css_file_directory = "data/spritesheets/[css_name]"
+
+	// sizes gets filled during should_refresh()
+	for(var/size_id in sizes)
+		var/fname = "data/spritesheets/[name]_[size_id].png"
+		if(!fexists(fname))
+			return FALSE
+
+	var/css_hash = rustg_hash_file(RUSTG_HASH_MD5, css_file_directory)
+	SSassets.transport.register_asset(css_name, fcopy_rsc(css_file_directory), file_hash=css_hash)
+	for(var/size_id in sizes)
+		var/fname = "data/spritesheets/[name]_[size_id].png"
+		var/hash = rustg_hash_file(RUSTG_HASH_MD5, fname)
+		SSassets.transport.register_asset("[name]_[size_id].png", fcopy_rsc(fname), file_hash=hash)
+
+	if(CONFIG_GET(flag/save_spritesheets))
+		save_to_logs(file_name = css_name, file_location = css_file_directory)
+
+	return TRUE
+
+/// Returns the URL to put in the background:url of the CSS asset
+/datum/asset/spritesheet_batched/proc/get_background_url(asset)
+	return SSassets.transport.get_asset_url(asset)
+
+/datum/asset/spritesheet_batched/proc/write_cache_meta(input_hash, dmi_hashes)
+	var/list/cache_data = list(
+		"input_hash" = input_hash,
+		"dmi_hashes" = dmi_hashes,
+		"sizes" = sizes,
+		"sprites" = sprites,
+		"rustg_version" = rustg_get_version(),
+		"dm_version" = SPRITESHEET_SYSTEM_VERSION,
+	)
+	rustg_file_write(json_encode(cache_data), "[ASSET_CROSS_ROUND_SMART_CACHE_DIRECTORY]/spritesheet_cache.[name].json")
+
+/**
+ * Third party helpers
+ * ===================
+ */
+
+/datum/asset/spritesheet_batched/proc/css_tag()
+	return {"<link rel="stylesheet" href="[css_filename()]" />"}
+
+/datum/asset/spritesheet_batched/proc/css_filename()
+	return SSassets.transport.get_asset_url("spritesheet_[name].css")
+
+/datum/asset/spritesheet_batched/proc/icon_tag(sprite_name)
+	var/sprite = sprites[sprite_name]
+	if (!sprite)
+		return null
+	var/size_id = sprite[SPR_SIZE]
+	return "<span class='[name][size_id] [sprite_name]'></span>"
+
+/datum/asset/spritesheet_batched/proc/icon_class_name(sprite_name)
+	var/sprite = sprites[sprite_name]
+	if (!sprite)
+		return null
+	var/size_id = sprite[SPR_SIZE]
+	return "[name][size_id] [sprite_name]"
+
+/**
+ * Returns the size class (ex design32x32) for a given sprite's icon
+ *
+ * Arguments:
+ * * sprite_name - The sprite to get the size of
+ */
+/datum/asset/spritesheet_batched/proc/icon_size_id(sprite_name)
+	var/sprite = sprites[sprite_name]
+	if (!sprite)
+		return null
+	var/size_id = sprite[SPR_SIZE]
+	return "[name][size_id]"
+
+#undef SPR_SIZE
+#undef SPR_IDX
+#undef CACHE_WAIT
+#undef CACHE_INVALID
+#undef CACHE_VALID
+#undef SPRITESHEET_SYSTEM_VERSION

code/modules/asset_cache/spritesheet/batched/universal_icon.dm

@@ -0,0 +1,374 @@
+/// This is intended to replace /icon, allowing rustg to generate icons much faster than DM can at scale.
+/// Construct these with the uni_icon() proc, in the same manner as BYOND's icon() proc.
+/// Additionally supports a number of transform procs (lowercase, rather than BYOND's uppercase)
+/// such as Crop, Scale, and Blend (as blend_icon/blend_color).
+/datum/universal_icon
+	var/icon/icon_file
+	var/icon_state
+	var/dir
+	var/frame
+	var/datum/icon_transformer/transform
+
+/// Don't instantiate these yourself, use uni_icon.
+/datum/universal_icon/New(icon/icon_file, icon_state="", dir=SOUTH, frame=1, datum/icon_transformer/transform=null, color=null)
+	#ifdef UNIT_TESTS
+	// This check is kinda slow and shouldn't fail unless a developer makes a mistake. So it'll get caught in unit tests.
+	if(!isicon(icon_file) || !isfile(icon_file) || "[icon_file]" == "/icon" || !length("[icon_file]"))
+		// bad! use 'icons/path_to_dmi.dmi' format only
+		CRASH("FATAL: universal_icon was provided icon_file: [icon_file] - icons provided to batched spritesheets MUST be DMI files, they cannot be /image, /icon, or other runtime generated icons.")
+	#endif
+	src.icon_file = icon_file
+	src.icon_state = icon_state
+	src.dir = dir
+	src.frame = frame
+	if(isnull(transform) && !isnull(color) && uppertext(color) != "#FFFFFF")
+		var/datum/icon_transformer/T = new()
+		if(color)
+			T.blend_color(color, ICON_MULTIPLY)
+		src.transform = T
+	else if(!isnull(transform))
+		src.transform = transform
+	else // null = empty list
+		src.transform = null
+
+/datum/universal_icon/proc/copy()
+	RETURN_TYPE(/datum/universal_icon)
+	var/datum/universal_icon/new_icon = new(icon_file, icon_state, dir, frame)
+	if(!isnull(src.transform))
+		new_icon.transform = src.transform.copy()
+	return new_icon
+
+/datum/universal_icon/proc/blend_color(color, blend_mode)
+	if(!transform)
+		transform = new
+	transform.blend_color(color, blend_mode)
+	return src
+
+/datum/universal_icon/proc/blend_icon(datum/universal_icon/icon_object, blend_mode)
+	if(!transform)
+		transform = new
+	transform.blend_icon(icon_object, blend_mode)
+	return src
+
+/datum/universal_icon/proc/scale(width, height)
+	if(!transform)
+		transform = new
+	transform.scale(width, height)
+	return src
+
+/datum/universal_icon/proc/crop(x1, y1, x2, y2)
+	if(!transform)
+		transform = new
+	transform.crop(x1, y1, x2, y2)
+	return src
+
+/// Internally performs a crop.
+/datum/universal_icon/proc/shift(dir, amount, icon_width, icon_height)
+	if(!transform)
+		transform = new
+	var/list/offsets = dir2offset(dir)
+	var/shift_x = -offsets[1] * amount
+	var/shift_y = -offsets[2] * amount
+	transform.crop(1 + shift_x, 1 + shift_y, icon_width + shift_x, icon_height + shift_y)
+	return src
+
+/// Internally performs a color blend.
+/// Amount ranges from 0-1 (100% opacity)
+/datum/universal_icon/proc/change_opacity(amount)
+	if(!transform)
+		transform = new
+	transform.blend_color("#ffffff[num2hex(clamp(amount, 0, 1) * 255, 2)]", ICON_MULTIPLY)
+	return src
+
+
+/datum/universal_icon/proc/to_list()
+	RETURN_TYPE(/list)
+	return list("icon_file" = "[icon_file]", "icon_state" = icon_state, "dir" = dir, "frame" = frame, "transform" = !isnull(transform) ? transform.to_list() : list())
+
+/proc/universal_icon_from_list(list/input_in)
+	RETURN_TYPE(/datum/universal_icon)
+	var/list/input = input_in.Copy() // copy, since icon_transformer_from_list will mutate the list.
+	return uni_icon(input["icon_file"], input["icon_state"], input["dir"], input["frame"], icon_transformer_from_list(input["transform"]))
+
+/datum/universal_icon/proc/to_json()
+	return json_encode(to_list())
+
+/datum/universal_icon/proc/to_icon()
+	RETURN_TYPE(/icon)
+	var/icon/self = icon(src.icon_file, src.icon_state, dir=src.dir, frame=src.frame)
+	if(istype(src.transform))
+		src.transform.apply(self)
+	return self
+
+/datum/icon_transformer
+	var/list/transforms = null
+
+/datum/icon_transformer/New()
+	transforms = list()
+
+/// Applies the contained set of transforms to an icon
+/datum/icon_transformer/proc/apply(icon/target)
+	RETURN_TYPE(/icon)
+	for(var/transform in src.transforms)
+		switch(transform["type"])
+			if(RUSTG_ICONFORGE_BLEND_COLOR)
+				target.Blend(transform["color"], transform["blend_mode"])
+			if(RUSTG_ICONFORGE_BLEND_ICON)
+				var/datum/universal_icon/icon_object = transform["icon"]
+				if(!istype(icon_object))
+					stack_trace("Invalid icon found in icon transformer during apply()! [icon_object]")
+					continue
+				target.Blend(icon_object.to_icon(), transform["blend_mode"])
+			if(RUSTG_ICONFORGE_SCALE)
+				target.Scale(transform["width"], transform["height"])
+			if(RUSTG_ICONFORGE_CROP)
+				target.Crop(transform["x1"], transform["y1"], transform["x2"], transform["y2"])
+	return target
+
+/datum/icon_transformer/proc/copy()
+	RETURN_TYPE(/datum/icon_transformer)
+	var/datum/icon_transformer/new_transformer = new()
+	new_transformer.transforms = list()
+	for(var/transform in src.transforms)
+		new_transformer.transforms += list(deep_copy_list_alt(transform))
+	return new_transformer
+
+/datum/icon_transformer/proc/blend_color(color, blend_mode)
+	#ifdef UNIT_TESTS
+	if(!istext(color))
+		CRASH("Invalid color provided to blend_color: [color]")
+	if(!isnum(blend_mode))
+		CRASH("Invalid blend_mode provided to blend_color: [blend_mode]")
+	#endif
+	transforms += list(list("type" = RUSTG_ICONFORGE_BLEND_COLOR, "color" = color, "blend_mode" = blend_mode))
+
+/datum/icon_transformer/proc/blend_icon(datum/universal_icon/icon_object, blend_mode)
+	#ifdef UNIT_TESTS
+	// icon_object's type is checked later in to_list
+	if(!isnum(blend_mode))
+		CRASH("Invalid blend_mode provided to blend_icon: [blend_mode]")
+	#endif
+	transforms += list(list("type" = RUSTG_ICONFORGE_BLEND_ICON, "icon" = icon_object, "blend_mode" = blend_mode))
+
+/datum/icon_transformer/proc/scale(width, height)
+	#ifdef UNIT_TESTS
+	if(!isnum(width) || !isnum(height))
+		CRASH("Invalid arguments provided to scale: [width],[height]")
+	#endif
+	transforms += list(list("type" = RUSTG_ICONFORGE_SCALE, "width" = width, "height" = height))
+
+/datum/icon_transformer/proc/crop(x1, y1, x2, y2)
+	#ifdef UNIT_TESTS
+	if(!isnum(x1) || !isnum(y1) || !isnum(x2) || !isnum(y2))
+		CRASH("Invalid arguments provided to crop: [x1],[y1],[x2],[y2]")
+	#endif
+	transforms += list(list("type" = RUSTG_ICONFORGE_CROP, "x1" = x1, "y1" = y1, "x2" = x2, "y2" = y2))
+
+/// Recursively converts all contained [/datum/universal_icon]s and their associated [/datum/icon_transformer]s into list form so the transforms can be JSON encoded.
+/datum/icon_transformer/proc/to_list()
+	RETURN_TYPE(/list)
+	var/list/transforms_out = list()
+	var/list/transforms_original = src.transforms.Copy()
+	for(var/list/transform as anything in transforms_original)
+		var/list/this_transform = transform.Copy() // copy it so we don't mutate the original
+		if(transform["type"] == RUSTG_ICONFORGE_BLEND_ICON)
+			var/datum/universal_icon/icon_object = this_transform["icon"]
+			if(!istype(icon_object))
+				stack_trace("Invalid icon found in icon transformer during to_list()! [icon_object]")
+				continue
+			// This mutates the inner transform list!!! Make sure it only runs on copies.
+			this_transform["icon"] = icon_object.to_list()
+		transforms_out += list(this_transform)
+	return transforms_out
+
+/// Reverse operation of /datum/icon_transformer/to_list()
+/proc/icon_transformer_from_list(list/input)
+	RETURN_TYPE(/datum/icon_transformer)
+	var/list/transforms = list()
+	for(var/list/transform as anything in input)
+		// don't mutate the input :(
+		var/this_transform = transform.Copy()
+		if(transform["type"] == RUSTG_ICONFORGE_BLEND_ICON)
+			this_transform["icon"] = universal_icon_from_list(transform["icon"])
+		transforms += list(this_transform)
+	var/datum/icon_transformer/transformer = new()
+	transformer.transforms = transforms
+	return transformer
+
+/// Constructs a transformer, with optional color multiply pre-added.
+/proc/color_transform(color=null)
+	RETURN_TYPE(/datum/icon_transformer)
+	var/datum/icon_transformer/transform = new()
+	if(color)
+		transform.blend_color(color, ICON_MULTIPLY)
+	return transform
+
+/// Converts a GAGS atom to a universal icon by generating blend operations.
+/proc/gags_to_universal_icon(atom/path)
+	RETURN_TYPE(/datum/universal_icon)
+	if(!ispath(path, /atom) || !initial(path.greyscale_config) || !initial(path.greyscale_colors))
+		CRASH("gags_to_universal_icon() received an invalid path of \"[path]\"!")
+	var/datum/greyscale_config/config = initial(path.greyscale_config)
+	var/colors = initial(path.greyscale_colors)
+	var/datum/universal_icon/entry = SSgreyscale.GetColoredIconByTypeUniversalIcon(config, colors, initial(path.icon_state))
+	return entry
+
+/// Gets the relevant universal icon for an atom, when displayed in TGUI. (see: icon_state_preview)
+/// Supports GAGS items and colored items.
+/proc/get_display_icon_for(atom/atom_path)
+	if (!ispath(atom_path, /atom))
+		return FALSE
+	var/icon_file = initial(atom_path.icon)
+	var/icon_state = initial(atom_path.icon_state)
+	if(initial(atom_path.greyscale_config) && initial(atom_path.greyscale_colors))
+		return gags_to_universal_icon(atom_path)
+	if(ispath(atom_path, /obj))
+		var/obj/obj_path = atom_path
+		if(initial(obj_path.icon_state_preview))
+			icon_state = initial(obj_path.icon_state_preview)
+	return uni_icon(icon_file, icon_state, color=initial(atom_path.color))
+
+/// getFlatIcon for [/datum/universal_icon]s
+/// Only supports 32x32 icons facing south
+/// Tough luck if you want anything else
+/// Still fairly slow for complex appearances due to filesystem operations. Try to avoid using it
+/proc/get_flat_uni_icon(image/appearance, deficon, defstate, defblend, start = TRUE, parentcolor)
+	// Loop through the underlays, then overlays, sorting them into the layers list
+	#define PROCESS_OVERLAYS_OR_UNDERLAYS(flat, process, base_layer) \
+		for (var/i in 1 to process.len) { \
+			var/image/current = process[i]; \
+			if (!current) { \
+				continue; \
+			} \
+			if (current.plane != FLOAT_PLANE && current.plane != appearance.plane) { \
+				continue; \
+			} \
+			var/current_layer = current.layer; \
+			if (current_layer < 0) { \
+				if (current_layer <= -1000) { \
+					return flat; \
+				} \
+				current_layer = base_layer + appearance.layer + current_layer / 1000; \
+			} \
+			/* If we are using topdown rendering, chop that part off so things layer together as expected */ \
+			if((current_layer >= TOPDOWN_LAYER && current_layer < EFFECTS_LAYER) || current_layer > TOPDOWN_LAYER + EFFECTS_LAYER) { \
+				current_layer -= TOPDOWN_LAYER; \
+			} \
+			for (var/index_to_compare_to in 1 to layers.len) { \
+				var/compare_to = layers[index_to_compare_to]; \
+				if (current_layer < layers[compare_to]) { \
+					layers.Insert(index_to_compare_to, current); \
+					break; \
+				} \
+			} \
+			layers[current] = current_layer; \
+		}
+
+	var/datum/universal_icon/flat = uni_icon('icons/blanks/32x32.dmi', "nothing")
+
+	if(!appearance || appearance.alpha <= 0)
+		return flat
+
+	if(start)
+		if(!deficon)
+			deficon = appearance.icon
+		if(!defstate)
+			defstate = appearance.icon_state
+		if(!defblend)
+			defblend = appearance.blend_mode
+
+	var/should_display = TRUE
+	var/curicon = appearance.icon || deficon
+	var/string_curicon = "[curicon]"
+	var/curstate = appearance.icon_state || defstate
+	// Filter out 'runtime' icons (server-generated RSC cache icons)
+	// Write the icon to the filesystem so it can be used by iconforge
+	if(!isfile(curicon) || string_curicon == "/icon" || string_curicon == "/image" || !length(string_curicon))
+		var/file_path_tmp = "tmp/uni_icon-tmp-[rand(1, 999)].dmi" // this filename is temporary.
+		fcopy(curicon, file_path_tmp)
+		var/file_hash = rustg_hash_file(RUSTG_HASH_MD5, file_path_tmp)
+		// Use the hash as its new filename - this allows the uni_icon to be smart cached, because the filename will be consistent between runs if the content is the same
+		var/file_path = "tmp/uni_icon-[file_hash].dmi"
+		fcopy(file_path_tmp, file_path)
+		fdel(file_path_tmp) // delete the old one
+		curicon = file(file_path)
+
+	var/curblend = appearance.blend_mode || defblend
+	var/list/curstates = icon_states(curicon)
+	if(!(curstate in curstates))
+		if("" in curstates) // BYOND defaulting functionality
+			curstate = ""
+		else
+			should_display = FALSE
+
+	if(appearance.overlays.len || appearance.underlays.len)
+		// Layers will be a sorted list of icons/overlays, based on the order in which they are displayed
+		var/list/layers = list()
+		var/image/copy
+		if(should_display)
+			// Add the atom's icon itself, without pixel_x/y offsets.
+			copy = image(icon=curicon, icon_state=curstate, layer=appearance.layer, dir=SOUTH)
+			copy.color = appearance.color
+			copy.alpha = appearance.alpha
+			copy.blend_mode = curblend
+			layers[copy] = appearance.layer
+
+		PROCESS_OVERLAYS_OR_UNDERLAYS(flat, appearance.underlays, 0)
+		PROCESS_OVERLAYS_OR_UNDERLAYS(flat, appearance.overlays, 1)
+
+		var/datum/universal_icon/add // Icon of overlay being added
+
+		if(appearance.color)
+			if(islist(appearance.color))
+				stack_trace("Unsupported color map appearance provided to get_flat_uni_icon, ignoring it.")
+			else
+				flat.blend_color(appearance.color, ICON_MULTIPLY)
+
+		if(parentcolor && !(appearance.appearance_flags & RESET_COLOR))
+			if(islist(parentcolor))
+				stack_trace("Unsupported color map appearance provided to get_flat_uni_icon, ignoring it.")
+			else
+				flat.blend_color(parentcolor, ICON_MULTIPLY)
+
+		var/next_parentcolor = appearance.color || parentcolor
+
+		for(var/image/layer_image as anything in layers)
+			if(layer_image.alpha == 0)
+				continue
+
+			if(layer_image == copy && length("[layer_image.icon]")) // 'layer_image' is an /image based on the object being flattened, and isn't a 'runtime' icon.
+				curblend = BLEND_OVERLAY
+				add = uni_icon(layer_image.icon, layer_image.icon_state, SOUTH)
+				if(appearance.color)
+					if(islist(appearance.color))
+						stack_trace("Unsupported color map appearance provided to get_flat_uni_icon, ignoring it.")
+					else
+						add.blend_color(appearance.color, ICON_MULTIPLY)
+			else // 'layer_image' is an appearance object.
+				add = get_flat_uni_icon(layer_image, curicon, curstate, curblend, FALSE, next_parentcolor)
+			if(!add || !length(add.icon_file))
+				continue
+
+			// Blend the overlay into the flattened icon
+			flat.blend_icon(add, blendMode2iconMode(curblend))
+
+		if(appearance.alpha < 255)
+			flat.blend_color(rgb(255, 255, 255, appearance.alpha), ICON_MULTIPLY)
+
+		return flat
+
+	else if(should_display) // There's no overlays.
+		var/datum/universal_icon/final_icon = uni_icon(curicon, curstate, SOUTH)
+
+		if (appearance.alpha < 255)
+			final_icon.blend_color(rgb(255,255,255, appearance.alpha), ICON_MULTIPLY)
+
+		if (appearance.color)
+			if (islist(appearance.color))
+				stack_trace("Unsupported color map appearance provided to get_flat_uni_icon, ignoring it.")
+			else
+				final_icon.blend_color(appearance.color, ICON_MULTIPLY)
+
+		return final_icon
+
+	#undef PROCESS_OVERLAYS_OR_UNDERLAYS

code/modules/asset_cache/spritesheet/legacy/legacy_spritesheet.dm

@@ -0,0 +1,418 @@
+
+// spritesheet implementation - coalesces various icons into a single .png file
+// and uses CSS to select icons out of that file - saves on transferring some
+// 1400-odd individual PNG files
+#define SPR_SIZE 1
+#define SPR_IDX 2
+#define SPRSZ_COUNT 1
+#define SPRSZ_ICON 2
+#define SPRSZ_STRIPPED 3
+
+/// Deprecated: Use /datum/asset/spritesheet_batched where possible
+/datum/asset/spritesheet
+	_abstract = /datum/asset/spritesheet
+	cross_round_cachable = TRUE
+	var/name
+	/// List of arguments to pass into queuedInsert
+	/// Exists so we can queue icon insertion, mostly for stuff like preferences
+	var/list/to_generate = list()
+	var/list/sizes = list()    // "32x32" -> list(10, icon/normal, icon/stripped)
+	var/list/sprites = list()  // "foo_bar" -> list("32x32", 5)
+	var/list/cached_spritesheets_needed
+	var/generating_cache = FALSE
+	var/fully_generated = FALSE
+	/// If this asset should be fully loaded on new
+	/// Defaults to false so we can process this stuff nicely
+	var/load_immediately = FALSE
+	// Kept in state so that the result is the same, even when the files are created, for this run
+	VAR_PRIVATE/should_refresh = null
+
+/datum/asset/spritesheet/proc/should_load_immediately()
+#ifdef DO_NOT_DEFER_ASSETS
+	return TRUE
+#else
+	return load_immediately
+#endif
+
+
+/datum/asset/spritesheet/should_refresh()
+	if (..())
+		return TRUE
+
+	if (isnull(should_refresh))
+		// `fexists` seems to always fail on static-time
+		should_refresh = !fexists(css_cache_filename()) || !fexists(data_cache_filename())
+
+	return should_refresh
+
+/datum/asset/spritesheet/unregister()
+	SSassets.transport.unregister_asset("spritesheet_[name].css")
+	if(length(sizes))
+		for(var/size_id in sizes)
+			SSassets.transport.unregister_asset("[name]_[size_id].png")
+	else
+		for(var/sheet in cached_spritesheets_needed)
+			SSassets.transport.unregister_asset(sheet)
+
+/datum/asset/spritesheet/regenerate()
+	unregister()
+	sprites = list()
+	fdel("[ASSET_CROSS_ROUND_CACHE_DIRECTORY]/spritesheet.[name].css")
+	for(var/sheet in cached_spritesheets_needed)
+		fdel("[ASSET_CROSS_ROUND_CACHE_DIRECTORY]/spritesheet.[sheet].png")
+	fdel("data/spritesheets/spritesheet_[name].css")
+	for(var/size_id in sizes)
+		fdel("data/spritesheets/[name]_[size_id].png")
+	sizes = list()
+	to_generate = list()
+	cached_serialized_url_mappings = null
+	cached_serialized_url_mappings_transport_type = null
+	fully_generated = FALSE
+	var/old_load = load_immediately
+	load_immediately = TRUE
+	create_spritesheets()
+	realize_spritesheets(yield = FALSE)
+	load_immediately = old_load
+
+/datum/asset/spritesheet/register()
+	SHOULD_NOT_OVERRIDE(TRUE)
+
+	if (!name)
+		CRASH("spritesheet [type] cannot register without a name")
+
+	if (!should_refresh() && read_from_cache())
+		fully_generated = TRUE
+		return
+
+	// If it's cached, may as well load it now, while the loading is cheap
+	if(CONFIG_GET(flag/cache_assets) && cross_round_cachable)
+		load_immediately = TRUE
+
+	create_spritesheets()
+	if(should_load_immediately())
+		realize_spritesheets(yield = FALSE)
+	else
+		SSasset_loading.queue_asset(src)
+
+/datum/asset/spritesheet/proc/realize_spritesheets(yield)
+	if(fully_generated)
+		return
+	while(length(to_generate))
+		var/list/stored_args = to_generate[to_generate.len]
+		to_generate.len--
+		queuedInsert(arglist(stored_args))
+		if(yield && TICK_CHECK)
+			return
+
+	ensure_stripped()
+	for(var/size_id in sizes)
+		var/size = sizes[size_id]
+		var/file_path = size[SPRSZ_STRIPPED]
+		var/file_hash = rustg_hash_file(RUSTG_HASH_MD5, file_path)
+		SSassets.transport.register_asset("[name]_[size_id].png", file_path, file_hash=file_hash)
+	var/css_name = "spritesheet_[name].css"
+	var/file_directory = "data/spritesheets/[css_name]"
+	fdel(file_directory)
+	var/css = generate_css()
+	rustg_file_write(css, file_directory)
+	var/css_hash = rustg_hash_string(RUSTG_HASH_MD5, css)
+	SSassets.transport.register_asset(css_name, fcopy_rsc(file_directory), file_hash=css_hash)
+
+	if(CONFIG_GET(flag/save_spritesheets))
+		save_to_logs(file_name = css_name, file_location = file_directory)
+
+	fdel(file_directory)
+
+	if (CONFIG_GET(flag/cache_assets) && cross_round_cachable)
+		write_to_cache()
+	fully_generated = TRUE
+	// If we were ever in there, remove ourselves
+	SSasset_loading.dequeue_asset(src)
+
+/datum/asset/spritesheet/queued_generation()
+	realize_spritesheets(yield = TRUE)
+
+/datum/asset/spritesheet/ensure_ready()
+	if(!fully_generated)
+		realize_spritesheets(yield = FALSE)
+	return ..()
+
+/datum/asset/spritesheet/send(client/client)
+	if (!name)
+		return
+
+	if (!should_refresh())
+		return send_from_cache(client)
+
+	var/all = list("spritesheet_[name].css")
+	for(var/size_id in sizes)
+		all += "[name]_[size_id].png"
+	. = SSassets.transport.send_assets(client, all)
+
+/datum/asset/spritesheet/get_url_mappings()
+	if (!name)
+		return
+
+	if (!should_refresh())
+		return get_cached_url_mappings()
+
+	. = list("spritesheet_[name].css" = SSassets.transport.get_asset_url("spritesheet_[name].css"))
+	for(var/size_id in sizes)
+		.["[name]_[size_id].png"] = SSassets.transport.get_asset_url("[name]_[size_id].png")
+
+/datum/asset/spritesheet/proc/ensure_stripped(sizes_to_strip = sizes)
+	for(var/size_id in sizes_to_strip)
+		var/size = sizes[size_id]
+		if (size[SPRSZ_STRIPPED])
+			continue
+
+		// save flattened version
+		var/png_name = "[name]_[size_id].png"
+		var/file_directory = "data/spritesheets/[png_name]"
+		fcopy(size[SPRSZ_ICON], file_directory)
+		var/error = rustg_dmi_strip_metadata(file_directory)
+		if(length(error))
+			stack_trace("Failed to strip [png_name]: [error]")
+		size[SPRSZ_STRIPPED] = icon(file_directory)
+
+		// this is useful here for determining if weird sprite issues (like having a white background) are a cause of what we're doing DM-side or not since we can see the full flattened thing at-a-glance.
+		if(CONFIG_GET(flag/save_spritesheets))
+			save_to_logs(file_name = png_name, file_location = file_directory)
+
+		fdel(file_directory)
+
+/datum/asset/spritesheet/proc/generate_css()
+	var/list/out = list()
+
+	for (var/size_id in sizes)
+		var/size = sizes[size_id]
+		var/list/dimensions = get_icon_dimensions(size[SPRSZ_ICON])
+		out += ".[name][size_id]{display:inline-block;width:[dimensions["width"]]px;height:[dimensions["height"]]px;background-image:url('[get_background_url("[name]_[size_id].png")]');background-repeat:no-repeat;}"
+
+	for (var/sprite_id in sprites)
+		var/sprite = sprites[sprite_id]
+		var/size_id = sprite[SPR_SIZE]
+		var/idx = sprite[SPR_IDX]
+		var/size = sizes[size_id]
+
+		var/list/tiny_dimensions = get_icon_dimensions(size[SPRSZ_ICON])
+		var/icon/big = size[SPRSZ_STRIPPED]
+		// big width won't be cached ever
+		var/per_line = big.Width() / tiny_dimensions["width"]
+		var/x = (idx % per_line) * tiny_dimensions["width"]
+		var/y = round(idx / per_line) * tiny_dimensions["height"]
+
+		out += ".[name][size_id].[sprite_id]{background-position:-[x]px -[y]px;}"
+
+	return out.Join("\n")
+
+/datum/asset/spritesheet/proc/css_cache_filename()
+	return "[ASSET_CROSS_ROUND_CACHE_DIRECTORY]/spritesheet.[name].css"
+
+/datum/asset/spritesheet/proc/data_cache_filename()
+	return "[ASSET_CROSS_ROUND_CACHE_DIRECTORY]/spritesheet.[name].json"
+
+/datum/asset/spritesheet/proc/read_from_cache()
+	return read_css_from_cache() && read_data_from_cache()
+
+/datum/asset/spritesheet/proc/read_css_from_cache()
+	var/replaced_css = rustg_file_read(css_cache_filename())
+
+	var/regex/find_background_urls = regex(@"background-image:url\('%(.+?)%'\)", "g")
+	while (find_background_urls.Find(replaced_css))
+		var/asset_id = find_background_urls.group[1]
+		var/file_path = "[ASSET_CROSS_ROUND_CACHE_DIRECTORY]/spritesheet.[asset_id]"
+		// Hashing it here is a *lot* faster.
+		var/hash = rustg_hash_file(RUSTG_HASH_MD5, file_path)
+		var/asset_cache_item = SSassets.transport.register_asset(asset_id, file_path, file_hash=hash)
+		var/asset_url = SSassets.transport.get_asset_url(asset_cache_item = asset_cache_item)
+		replaced_css = replacetext(replaced_css, find_background_urls.match, "background-image:url('[asset_url]')")
+		LAZYADD(cached_spritesheets_needed, asset_id)
+
+	var/finalized_name = "spritesheet_[name].css"
+	var/replaced_css_filename = "data/spritesheets/[finalized_name]"
+	var/css_hash = rustg_hash_string(RUSTG_HASH_MD5, replaced_css)
+	rustg_file_write(replaced_css, replaced_css_filename)
+	SSassets.transport.register_asset(finalized_name, replaced_css_filename, file_hash=css_hash)
+
+	if(CONFIG_GET(flag/save_spritesheets))
+		save_to_logs(file_name = finalized_name, file_location = replaced_css_filename)
+
+	fdel(replaced_css_filename)
+
+	return TRUE
+
+/datum/asset/spritesheet/proc/read_data_from_cache()
+	var/json = json_decode(rustg_file_read(data_cache_filename()))
+
+	if (islist(json["sprites"]))
+		sprites = json["sprites"]
+
+	return TRUE
+
+/datum/asset/spritesheet/proc/send_from_cache(client/client)
+	if (isnull(cached_spritesheets_needed))
+		stack_trace("cached_spritesheets_needed was null when sending assets from [type] from cache")
+		cached_spritesheets_needed = list()
+
+	return SSassets.transport.send_assets(client, cached_spritesheets_needed + "spritesheet_[name].css")
+
+/// Returns the URL to put in the background:url of the CSS asset
+/datum/asset/spritesheet/proc/get_background_url(asset)
+	if (generating_cache)
+		return "%[asset]%"
+	else
+		return SSassets.transport.get_asset_url(asset)
+
+/datum/asset/spritesheet/proc/write_to_cache()
+	write_css_to_cache()
+	write_data_to_cache()
+
+/datum/asset/spritesheet/proc/write_css_to_cache()
+	for (var/size_id in sizes)
+		fcopy(SSassets.cache["[name]_[size_id].png"].resource, "[ASSET_CROSS_ROUND_CACHE_DIRECTORY]/spritesheet.[name]_[size_id].png")
+
+	generating_cache = TRUE
+	var/mock_css = generate_css()
+	generating_cache = FALSE
+
+	rustg_file_write(mock_css, css_cache_filename())
+
+/datum/asset/spritesheet/proc/write_data_to_cache()
+	rustg_file_write(json_encode(list(
+		"sprites" = sprites,
+	)), data_cache_filename())
+
+/datum/asset/spritesheet/proc/get_cached_url_mappings()
+	var/list/mappings = list()
+	mappings["spritesheet_[name].css"] = SSassets.transport.get_asset_url("spritesheet_[name].css")
+
+	for (var/asset_name in cached_spritesheets_needed)
+		mappings[asset_name] = SSassets.transport.get_asset_url(asset_name)
+
+	return mappings
+
+/// Override this in order to start the creation of the spritehseet.
+/// This is where all your Insert, InsertAll, etc calls should be inside.
+/datum/asset/spritesheet/proc/create_spritesheets()
+	CRASH("create_spritesheets() not implemented for [type]!")
+
+/datum/asset/spritesheet/proc/Insert(sprite_name, icon/inserted_icon, icon_state="", dir=SOUTH, frame=1, moving=FALSE)
+	if(should_load_immediately())
+		queuedInsert(sprite_name, inserted_icon, icon_state, dir, frame, moving)
+	else
+		to_generate += list(args.Copy())
+
+/datum/asset/spritesheet/proc/queuedInsert(sprite_name, icon/inserted_icon, icon_state="", dir=SOUTH, frame=1, moving=FALSE)
+#ifdef UNIT_TESTS
+	if (inserted_icon && icon_state && !icon_exists(inserted_icon, icon_state)) // check the base icon prior to extracting the state we want
+		stack_trace("Tried to insert nonexistent icon_state '[icon_state]' from [inserted_icon] into spritesheet [name] ([type])")
+		return
+#endif
+	inserted_icon = icon(inserted_icon, icon_state=icon_state, dir=dir, frame=frame, moving=moving)
+	if (!inserted_icon || !length(icon_states(inserted_icon)))  // that direction or state doesn't exist
+		return
+
+	var/start_usage = world.tick_usage
+
+	//any sprite modifications we want to do (aka, coloring a greyscaled asset)
+	inserted_icon = ModifyInserted(inserted_icon)
+	var/list/dimensions = get_icon_dimensions(inserted_icon)
+	var/size_id = "[dimensions["width"]]x[dimensions["height"]]"
+	var/size = sizes[size_id]
+
+	if (sprites[sprite_name])
+		CRASH("duplicate sprite \"[sprite_name]\" in sheet [name] ([type])")
+
+	if (size)
+		var/position = size[SPRSZ_COUNT]++
+		// Icons are essentially representations of files + modifications
+		// Because of this, byond keeps them in a cache. It does this in a really dumb way tho
+		// It's essentially a FIFO queue. So after we do icon() some amount of times, our old icons go out of cache
+		// When this happens it becomes impossible to modify them, trying to do so will instead throw a
+		// "bad icon" error.
+		// What we're doing here is ensuring our icon is in the cache by refreshing it, so we can modify it w/o runtimes.
+		var/icon/sheet = size[SPRSZ_ICON]
+		var/icon/sheet_copy = icon(sheet)
+		size[SPRSZ_STRIPPED] = null
+		sheet_copy.Insert(inserted_icon, icon_state=sprite_name)
+		size[SPRSZ_ICON] = sheet_copy
+
+		sprites[sprite_name] = list(size_id, position)
+	else
+		sizes[size_id] = size = list(1, inserted_icon, null)
+		sprites[sprite_name] = list(size_id, 0)
+
+	SSblackbox.record_feedback("tally", "spritesheet_queued_insert_time", TICK_USAGE_TO_MS(start_usage), name)
+
+/**
+ * A simple proc handing the Icon for you to modify before it gets turned into an asset.
+ *
+ * Arguments:
+ * * I: icon being turned into an asset
+ */
+/datum/asset/spritesheet/proc/ModifyInserted(icon/pre_asset)
+	return pre_asset
+
+/datum/asset/spritesheet/proc/InsertAll(prefix, icon/inserted_icon, list/directions)
+	if (length(prefix))
+		prefix = "[prefix]-"
+
+	if (!directions)
+		directions = list(SOUTH)
+
+	for (var/icon_state_name in icon_states(inserted_icon))
+		for (var/direction in directions)
+			var/prefix2 = (directions.len > 1) ? "[dir2text(direction)]-" : ""
+			Insert("[prefix][prefix2][icon_state_name]", inserted_icon, icon_state=icon_state_name, dir=direction)
+
+/datum/asset/spritesheet/proc/css_tag()
+	return {"<link rel="stylesheet" href="[css_filename()]" />"}
+
+/datum/asset/spritesheet/proc/css_filename()
+	return SSassets.transport.get_asset_url("spritesheet_[name].css")
+
+/datum/asset/spritesheet/proc/icon_tag(sprite_name)
+	var/sprite = sprites[sprite_name]
+	if (!sprite)
+		return null
+	var/size_id = sprite[SPR_SIZE]
+	return {"<span class='[name][size_id] [sprite_name]'></span>"}
+
+/datum/asset/spritesheet/proc/icon_class_name(sprite_name)
+	var/sprite = sprites[sprite_name]
+	if (!sprite)
+		return null
+	var/size_id = sprite[SPR_SIZE]
+	return {"[name][size_id] [sprite_name]"}
+
+/**
+ * Returns the size class (ex design32x32) for a given sprite's icon
+ *
+ * Arguments:
+ * * sprite_name - The sprite to get the size of
+ */
+/datum/asset/spritesheet/proc/icon_size_id(sprite_name)
+	var/sprite = sprites[sprite_name]
+	if (!sprite)
+		return null
+	var/size_id = sprite[SPR_SIZE]
+	return "[name][size_id]"
+
+#undef SPR_SIZE
+#undef SPR_IDX
+#undef SPRSZ_COUNT
+#undef SPRSZ_ICON
+#undef SPRSZ_STRIPPED
+
+/// Spritesheet that only uses simple PNGs and CSS keys. See `assets` variable.
+/// Deprecated: Use /datum/asset/spritesheet_batched where possible
+/datum/asset/spritesheet/simple
+	_abstract = /datum/asset/spritesheet/simple
+	/// Associative list of icon keys (CSS class names) -> PNG filepaths (single quote!)
+	/// File paths MUST be PNGs
+	var/list/assets
+
+/datum/asset/spritesheet/simple/create_spritesheets()
+	for (var/key in assets)
+		Insert(key, assets[key])

code/modules/asset_cache/transports/asset_transport.dm

@@ -1,5 +1,3 @@
-/// When sending mutiple assets, how many before we give the client a quaint little sending resources message
-#define ASSET_CACHE_TELL_CLIENT_AMOUNT 8
 
 /// Base browse_rsc asset transport
 /datum/asset_transport
@@ -59,6 +57,10 @@
 	SSassets.cache[asset_name] = ACI
 	return ACI
 
+/// Immediately removes an asset from the asset cache.
+/datum/asset_transport/proc/unregister_asset(asset_name)
+	SSassets.cache[asset_name] = null
+	SSassets.cache.Remove(null)
 
 /// Returns a url for a given asset.
 /// asset_name - Name of the asset.
@@ -147,7 +149,7 @@
 
 
 /// Precache files without clogging up the browse() queue, used for passively sending files on connection start.
-/datum/asset_transport/proc/send_assets_slow(client/client, list/files, filerate = 6)
+/datum/asset_transport/proc/send_assets_slow(client/client, list/files, filerate = SLOW_ASSET_SEND_RATE)
 	var/startingfilerate = filerate
 	for (var/file in files)
 		if (!client)

code/modules/asset_cache/transports/webroot_transport.dm

@@ -1,4 +1,4 @@
-/// CDN Webroot asset transport. 
+/// CDN Webroot asset transport.
 /datum/asset_transport/webroot
 	name = "CDN Webroot asset transport"
 
@@ -16,7 +16,7 @@
 /// We also save it to the CDN webroot at this step instead of waiting for send_assets()
 /// asset_name - the identifier of the asset
 /// asset - the actual asset file or an asset_cache_item datum.
-/datum/asset_transport/webroot/register_asset(asset_name, asset)
+/datum/asset_transport/webroot/register_asset(asset_name, asset, file_hash, dmi_path)
 	. = ..()
 	var/datum/asset_cache_item/ACI = .
 
@@ -59,7 +59,7 @@
 	if (!islist(asset_list))
 		asset_list = list(asset_list)
 	for (var/asset_name in asset_list)
-		var/datum/asset_cache_item/ACI = asset_list[asset_name] 
+		var/datum/asset_cache_item/ACI = asset_list[asset_name]
 		if (!istype(ACI))
 			ACI = SSassets.cache[asset_name]
 		if (!ACI)
@@ -69,7 +69,7 @@
 			legacy_assets[asset_name] = ACI
 	if (length(legacy_assets))
 		. = ..(client, legacy_assets)
-	
+
 
 /// webroot slow asset sending - does nothing.
 /datum/asset_transport/webroot/send_assets_slow(client/client, list/files, filerate)

code/modules/cargo/centcom_podlauncher.dm

@@ -128,7 +128,7 @@ ADMIN_VERB(centcom_podlauncher, R_ADMIN, "Config/Launch Supplypod", "Configure a
 
 /datum/centcom_podlauncher/ui_assets(mob/user)
 	return list(
-		get_asset_datum(/datum/asset/spritesheet/supplypods),
+		get_asset_datum(/datum/asset/spritesheet_batched/supplypods),
 	)
 
 /datum/centcom_podlauncher/ui_interact(mob/user, datum/tgui/ui)

code/modules/client/preferences.dm

@@ -192,7 +192,7 @@ GLOBAL_LIST_EMPTY(preferences_datums)
 
 /datum/preferences/ui_assets(mob/user)
 	var/list/assets = list(
-		get_asset_datum(/datum/asset/spritesheet/preferences),
+		get_asset_datum(/datum/asset/spritesheet_batched/preferences),
 		get_asset_datum(/datum/asset/json/preferences),
 	)
 

code/modules/client/preferences/README.md

@@ -142,11 +142,11 @@ Choiced preferences can generate icons. This is how the clothing/species prefere
 /datum/preference/choiced/favorite_drink/icon_for(value)
 	switch (value)
 		if ("Milk")
-			return icon('drinks.dmi', "milk")
+			return uni_icon('drinks.dmi', "milk")
 		if ("Cola")
-			return icon('drinks.dmi', "cola")
+			return uni_icon('drinks.dmi', "cola")
 		if ("Water")
-			return icon('drinks.dmi', "water")
+			return uni_icon('drinks.dmi', "water")
 ```
 
 Then, change your `.tsx` file to look like:

code/modules/client/preferences/_preference.dm

@@ -405,7 +405,7 @@ GLOBAL_LIST_INIT(preference_entries_by_key, init_preference_entries_by_key())
 	CRASH("`init_possible_values()` was not implemented for [type]!")
 
 /// When `should_generate_icons` is TRUE, this proc is called for every value.
-/// It can return either an icon or a typepath to an atom to create.
+/// It can return either an /datum/universal_icon (see uni_icon() DEFINE) or a typepath to an atom to create.
 /datum/preference/choiced/proc/icon_for(value)
 	SHOULD_CALL_PARENT(FALSE)
 	SHOULD_NOT_SLEEP(TRUE)

code/modules/client/preferences/ai_core_display.dm

@@ -10,9 +10,9 @@
 
 /datum/preference/choiced/ai_core_display/icon_for(value)
 	if (value == "Random")
-		return icon('icons/mob/silicon/ai.dmi', "questionmark")
+		return uni_icon('icons/mob/silicon/ai.dmi', "questionmark")
 	else
-		return icon('icons/mob/silicon/ai.dmi', resolve_ai_icon_sync(value))
+		return uni_icon('icons/mob/silicon/ai.dmi', resolve_ai_icon_sync(value))
 
 /datum/preference/choiced/ai_core_display/is_accessible(datum/preferences/preferences)
 	if (!..(preferences))

code/modules/client/preferences/ai_emote_display.dm

@@ -10,9 +10,9 @@
 
 /datum/preference/choiced/ai_emote_display/icon_for(value)
 	if (value == "Random")
-		return icon('icons/mob/silicon/ai.dmi', "questionmark")
+		return uni_icon('icons/mob/silicon/ai.dmi', "questionmark")
 	else
-		return icon('icons/obj/machines/status_display.dmi', GLOB.ai_status_display_emotes[value])
+		return uni_icon('icons/obj/machines/status_display.dmi', GLOB.ai_status_display_emotes[value])
 
 /datum/preference/choiced/ai_emote_display/is_accessible(datum/preferences/preferences)
 	if (!..(preferences))

code/modules/client/preferences/ai_hologram_display.dm

@@ -10,9 +10,9 @@
 
 /datum/preference/choiced/ai_hologram_display/icon_for(value)
 	if (value == "Random")
-		return icon('icons/mob/silicon/ai.dmi', "questionmark")
+		return uni_icon('icons/mob/silicon/ai.dmi', "questionmark")
 	else
-		return icon(GLOB.ai_hologram_icons[value], GLOB.ai_hologram_icon_state[value])
+		return uni_icon(GLOB.ai_hologram_icons[value], GLOB.ai_hologram_icon_state[value])
 
 /datum/preference/choiced/ai_hologram_display/is_accessible(datum/preferences/preferences)
 	if (!..(preferences))

code/modules/client/preferences/assets.dm

@@ -1,11 +1,9 @@
 /// Assets generated from `/datum/preference` icons
-/datum/asset/spritesheet/preferences
+/datum/asset/spritesheet_batched/preferences
 	name = "preferences"
 	early = TRUE
 
-/datum/asset/spritesheet/preferences/create_spritesheets()
-	var/list/to_insert = list()
-
+/datum/asset/spritesheet_batched/preferences/create_spritesheets()
 	for (var/preference_key in GLOB.preference_entries_by_key)
 		var/datum/preference/choiced/preference = GLOB.preference_entries_by_key[preference_key]
 		if (!istype(preference))
@@ -17,23 +15,20 @@
 		for (var/preference_value in preference.get_choices())
 			var/create_icon_of = preference.icon_for(preference_value)
 
-			var/icon/icon
-			var/icon_state
+			var/datum/universal_icon/icon
 
 			if (ispath(create_icon_of, /atom))
 				var/atom/atom_icon_source = create_icon_of
-				icon = initial(atom_icon_source.icon)
-				icon_state = initial(atom_icon_source.icon_state)
-			else if (isicon(create_icon_of))
+				icon = get_display_icon_for(atom_icon_source)
+			else if (istype(create_icon_of, /datum/universal_icon))
 				icon = create_icon_of
+			else if (isicon(create_icon_of))
+				CRASH("Icon given for preference [preference_key]:[preference_value]. This is not supported anymore, provide a /datum/universal_icon instead.")
 			else
 				CRASH("[create_icon_of] is an invalid preference value (from [preference_key]:[preference_value]).")
-
-			to_insert[preference.get_spritesheet_key(preference.serialize(preference_value))] = list(icon, icon_state)
-
-	for (var/spritesheet_key in to_insert)
-		var/list/inserting = to_insert[spritesheet_key]
-		Insert(spritesheet_key, inserting[1], inserting[2])
+			// There's no cost associated with inserting uni_icons, so just insert them immediately.
+			var/spritesheet_key = preference.get_spritesheet_key(preference.serialize(preference_value))
+			insert_icon(spritesheet_key, icon)
 
 /// Returns the key that will be used in the spritesheet for a given value.
 /datum/preference/proc/get_spritesheet_key(value)

code/modules/client/preferences/clothing.dm

@@ -1,14 +1,14 @@
-/proc/generate_underwear_icon(datum/sprite_accessory/accessory, icon/base_icon, color)
-	var/icon/final_icon = new(base_icon)
+/proc/generate_underwear_icon(datum/sprite_accessory/accessory, datum/universal_icon/base_icon, color)
+	var/datum/universal_icon/final_icon = base_icon.copy()
 
 	if (!isnull(accessory))
-		var/icon/accessory_icon = icon('icons/mob/clothing/underwear.dmi', accessory.icon_state)
+		var/datum/universal_icon/accessory_icon = uni_icon('icons/mob/clothing/underwear.dmi', accessory.icon_state)
 		if (color && !accessory.use_static)
-			accessory_icon.Blend(color, ICON_MULTIPLY)
-		final_icon.Blend(accessory_icon, ICON_OVERLAY)
+			accessory_icon.blend_color(color, ICON_MULTIPLY)
+		final_icon.blend_icon(accessory_icon, ICON_OVERLAY)
 
-	final_icon.Crop(10, 1, 22, 13)
-	final_icon.Scale(32, 32)
+	final_icon.crop(10, 1, 22, 13)
+	final_icon.scale(32, 32)
 
 	return final_icon
 
@@ -109,12 +109,12 @@
 	return /datum/sprite_accessory/socks/nude::name
 
 /datum/preference/choiced/socks/icon_for(value)
-	var/static/icon/lower_half
+	var/static/datum/universal_icon/lower_half
 
 	if (isnull(lower_half))
-		lower_half = icon('icons/blanks/32x32.dmi', "nothing")
-		lower_half.Blend(icon('icons/mob/human/bodyparts_greyscale.dmi', "human_r_leg"), ICON_OVERLAY)
-		lower_half.Blend(icon('icons/mob/human/bodyparts_greyscale.dmi', "human_l_leg"), ICON_OVERLAY)
+		lower_half = uni_icon('icons/blanks/32x32.dmi', "nothing")
+		lower_half.blend_icon(uni_icon('icons/mob/human/bodyparts_greyscale.dmi', "human_r_leg"), ICON_OVERLAY)
+		lower_half.blend_icon(uni_icon('icons/mob/human/bodyparts_greyscale.dmi', "human_l_leg"), ICON_OVERLAY)
 
 	return generate_underwear_icon(SSaccessories.socks_list[value], lower_half)
 
@@ -147,24 +147,24 @@
 	return ..()
 
 /datum/preference/choiced/undershirt/icon_for(value)
-	var/static/icon/body
+	var/static/datum/universal_icon/body
 	if (isnull(body))
-		body = icon('icons/mob/human/bodyparts_greyscale.dmi', "human_r_leg")
-		body.Blend(icon('icons/mob/human/bodyparts_greyscale.dmi', "human_l_leg"), ICON_OVERLAY)
-		body.Blend(icon('icons/mob/human/bodyparts_greyscale.dmi', "human_r_arm"), ICON_OVERLAY)
-		body.Blend(icon('icons/mob/human/bodyparts_greyscale.dmi', "human_l_arm"), ICON_OVERLAY)
-		body.Blend(icon('icons/mob/human/bodyparts_greyscale.dmi', "human_r_hand"), ICON_OVERLAY)
-		body.Blend(icon('icons/mob/human/bodyparts_greyscale.dmi', "human_l_hand"), ICON_OVERLAY)
-		body.Blend(icon('icons/mob/human/bodyparts_greyscale.dmi', "human_chest_m"), ICON_OVERLAY)
+		body = uni_icon('icons/mob/human/bodyparts_greyscale.dmi', "human_r_leg")
+		body.blend_icon(uni_icon('icons/mob/human/bodyparts_greyscale.dmi', "human_l_leg"), ICON_OVERLAY)
+		body.blend_icon(uni_icon('icons/mob/human/bodyparts_greyscale.dmi', "human_r_arm"), ICON_OVERLAY)
+		body.blend_icon(uni_icon('icons/mob/human/bodyparts_greyscale.dmi', "human_l_arm"), ICON_OVERLAY)
+		body.blend_icon(uni_icon('icons/mob/human/bodyparts_greyscale.dmi', "human_r_hand"), ICON_OVERLAY)
+		body.blend_icon(uni_icon('icons/mob/human/bodyparts_greyscale.dmi', "human_l_hand"), ICON_OVERLAY)
+		body.blend_icon(uni_icon('icons/mob/human/bodyparts_greyscale.dmi', "human_chest_m"), ICON_OVERLAY)
 
-	var/icon/icon_with_undershirt = icon(body)
+	var/datum/universal_icon/icon_with_undershirt = body.copy()
 
 	if (value != "Nude")
 		var/datum/sprite_accessory/accessory = SSaccessories.undershirt_list[value]
-		icon_with_undershirt.Blend(icon('icons/mob/clothing/underwear.dmi', accessory.icon_state), ICON_OVERLAY)
+		icon_with_undershirt.blend_icon(uni_icon('icons/mob/clothing/underwear.dmi', accessory.icon_state), ICON_OVERLAY)
 
-	icon_with_undershirt.Crop(9, 9, 23, 23)
-	icon_with_undershirt.Scale(32, 32)
+	icon_with_undershirt.crop(9, 9, 23, 23)
+	icon_with_undershirt.scale(32, 32)
 	return icon_with_undershirt
 
 /datum/preference/choiced/undershirt/apply_to_human(mob/living/carbon/human/target, value)
@@ -186,13 +186,13 @@
 	return /datum/sprite_accessory/underwear/male_hearts::name
 
 /datum/preference/choiced/underwear/icon_for(value)
-	var/static/icon/lower_half
+	var/static/datum/universal_icon/lower_half
 
 	if (isnull(lower_half))
-		lower_half = icon('icons/blanks/32x32.dmi', "nothing")
-		lower_half.Blend(icon('icons/mob/human/bodyparts_greyscale.dmi', "human_chest_m"), ICON_OVERLAY)
-		lower_half.Blend(icon('icons/mob/human/bodyparts_greyscale.dmi', "human_r_leg"), ICON_OVERLAY)
-		lower_half.Blend(icon('icons/mob/human/bodyparts_greyscale.dmi', "human_l_leg"), ICON_OVERLAY)
+		lower_half = uni_icon('icons/blanks/32x32.dmi', "nothing")
+		lower_half.blend_icon(uni_icon('icons/mob/human/bodyparts_greyscale.dmi', "human_chest_m"), ICON_OVERLAY)
+		lower_half.blend_icon(uni_icon('icons/mob/human/bodyparts_greyscale.dmi', "human_r_leg"), ICON_OVERLAY)
+		lower_half.blend_icon(uni_icon('icons/mob/human/bodyparts_greyscale.dmi', "human_l_leg"), ICON_OVERLAY)
 
 	return generate_underwear_icon(SSaccessories.underwear_list[value], lower_half, COLOR_ALMOST_BLACK)
 

code/modules/client/preferences/ghost.dm

@@ -74,7 +74,7 @@
 	return assoc_to_keys(ghost_forms)
 
 /datum/preference/choiced/ghost_form/icon_for(value)
-	return icon('icons/mob/simple/mob.dmi', value)
+	return uni_icon('icons/mob/simple/mob.dmi', value)
 
 /datum/preference/choiced/ghost_form/create_default_value()
 	return "ghost"

code/modules/client/preferences/glasses.dm

@@ -12,9 +12,9 @@
 
 /datum/preference/choiced/glasses/icon_for(value)
 	if (value == "Random")
-		return icon('icons/effects/random_spawners.dmi', "questionmark")
+		return uni_icon('icons/effects/random_spawners.dmi', "questionmark")
 	else
-		return icon('icons/obj/clothing/glasses.dmi', "glasses_[LOWER_TEXT(value)]")
+		return uni_icon('icons/obj/clothing/glasses.dmi', "glasses_[LOWER_TEXT(value)]")
 
 /datum/preference/choiced/glasses/is_accessible(datum/preferences/preferences)
 	if (!..(preferences))

code/modules/client/preferences/middleware/species.dm

@@ -23,7 +23,7 @@
 
 		var/icon/dummy_icon = getFlatIcon(dummy)
 		dummy_icon.Scale(64, 64)
-		dummy_icon.Crop(15, 64, 15 + 31, 64 - 31)
+		dummy_icon.Crop(15, 64 - 31, 15 + 31, 64)
 		dummy_icon.Scale(64, 64)
 		to_insert[sanitize_css_class_name(initial(species_type.name))] = dummy_icon
 

code/modules/client/preferences/species_features/basic.dm

@@ -1,21 +1,21 @@
 /proc/generate_icon_with_head_accessory(datum/sprite_accessory/sprite_accessory, y_offset = 0)
-	var/static/icon/head_icon
+	var/static/datum/universal_icon/head_icon
 	if (isnull(head_icon))
-		head_icon = icon('icons/mob/human/bodyparts_greyscale.dmi', "human_head_m")
-		head_icon.Blend(skintone2hex("caucasian1"), ICON_MULTIPLY)
+		head_icon = uni_icon('icons/mob/human/bodyparts_greyscale.dmi', "human_head_m")
+		head_icon.blend_color(skintone2hex("caucasian1"), ICON_MULTIPLY)
 
-	var/icon/final_icon = new(head_icon)
-	if (!isnull(sprite_accessory))
+	var/datum/universal_icon/final_icon = head_icon.copy()
+	if (!isnull(sprite_accessory) && sprite_accessory.icon_state != SPRITE_ACCESSORY_NONE)
 		ASSERT(istype(sprite_accessory))
 
-		var/icon/head_accessory_icon = icon(sprite_accessory.icon, sprite_accessory.icon_state)
+		var/datum/universal_icon/head_accessory_icon = uni_icon(sprite_accessory.icon, sprite_accessory.icon_state)
 		if(y_offset)
-			head_accessory_icon.Shift(NORTH, y_offset)
-		head_accessory_icon.Blend(COLOR_DARK_BROWN, ICON_MULTIPLY)
-		final_icon.Blend(head_accessory_icon, ICON_OVERLAY)
+			head_accessory_icon.shift(NORTH, y_offset, ICON_SIZE_X, ICON_SIZE_Y)
+		head_accessory_icon.blend_color(COLOR_DARK_BROWN, ICON_MULTIPLY)
+		final_icon.blend_icon(head_accessory_icon, ICON_OVERLAY)
 
-	final_icon.Crop(10, 19, 22, 31)
-	final_icon.Scale(32, 32)
+	final_icon.crop(10, 19, 22, 31)
+	final_icon.scale(32, 32)
 
 	return final_icon
 

code/modules/client/preferences/species_features/ethereal.dm

@@ -9,22 +9,23 @@
 	return assoc_to_keys(GLOB.color_list_ethereal)
 
 /datum/preference/choiced/ethereal_color/icon_for(value)
-	var/static/icon/ethereal_base
+	var/static/datum/universal_icon/ethereal_base
 	if (isnull(ethereal_base))
-		ethereal_base = icon('icons/mob/human/species/ethereal/bodyparts.dmi', "ethereal_head")
-		ethereal_base.Blend(icon('icons/mob/human/species/ethereal/bodyparts.dmi', "ethereal_chest"), ICON_OVERLAY)
-		ethereal_base.Blend(icon('icons/mob/human/species/ethereal/bodyparts.dmi', "ethereal_l_arm"), ICON_OVERLAY)
-		ethereal_base.Blend(icon('icons/mob/human/species/ethereal/bodyparts.dmi', "ethereal_r_arm"), ICON_OVERLAY)
+		ethereal_base = uni_icon('icons/mob/human/species/ethereal/bodyparts.dmi', "ethereal_head")
+		ethereal_base.blend_icon(uni_icon('icons/mob/human/species/ethereal/bodyparts.dmi', "ethereal_chest"), ICON_OVERLAY)
+		ethereal_base.blend_icon(uni_icon('icons/mob/human/species/ethereal/bodyparts.dmi', "ethereal_l_arm"), ICON_OVERLAY)
+		ethereal_base.blend_icon(uni_icon('icons/mob/human/species/ethereal/bodyparts.dmi', "ethereal_r_arm"), ICON_OVERLAY)
 
-		var/icon/eyes = icon('icons/mob/human/human_face.dmi', "eyes")
-		eyes.Blend(COLOR_BLACK, ICON_MULTIPLY)
-		ethereal_base.Blend(eyes, ICON_OVERLAY)
+		var/datum/universal_icon/eyes = uni_icon('icons/mob/human/human_face.dmi', "eyes_l")
+		eyes.blend_icon(uni_icon('icons/mob/human/human_face.dmi', "eyes_r"), ICON_OVERLAY)
+		eyes.blend_color(COLOR_BLACK, ICON_MULTIPLY)
+		ethereal_base.blend_icon(eyes, ICON_OVERLAY)
 
-		ethereal_base.Scale(64, 64)
-		ethereal_base.Crop(15, 64, 15 + 31, 64 - 31)
+		ethereal_base.scale(64, 64)
+		ethereal_base.crop(15, 64 - 31, 15 + 31, 64)
 
-	var/icon/icon = new(ethereal_base)
-	icon.Blend(GLOB.color_list_ethereal[value], ICON_MULTIPLY)
+	var/datum/universal_icon/icon = ethereal_base.copy()
+	icon.blend_color(GLOB.color_list_ethereal[value], ICON_MULTIPLY)
 	return icon
 
 /datum/preference/choiced/ethereal_color/apply_to_human(mob/living/carbon/human/target, value)

code/modules/client/preferences/species_features/lizard.dm

@@ -1,25 +1,25 @@
 /proc/generate_lizard_side_shot(datum/sprite_accessory/sprite_accessory, key, include_snout = TRUE)
-	var/static/icon/lizard
-	var/static/icon/lizard_with_snout
+	var/static/datum/universal_icon/lizard
+	var/static/datum/universal_icon/lizard_with_snout
 
 	if (isnull(lizard))
-		lizard = icon('icons/mob/human/species/lizard/bodyparts.dmi', "lizard_head", EAST)
-		var/icon/eyes = icon('icons/mob/human/human_face.dmi', "eyes", EAST)
-		eyes.Blend(COLOR_GRAY, ICON_MULTIPLY)
-		lizard.Blend(eyes, ICON_OVERLAY)
+		lizard = uni_icon('icons/mob/human/species/lizard/bodyparts.dmi', "lizard_head", EAST)
+		var/datum/universal_icon/eyes = uni_icon('icons/mob/human/human_face.dmi', "eyes_l", EAST)
+		eyes.blend_color(COLOR_GRAY, ICON_MULTIPLY)
+		lizard.blend_icon(eyes, ICON_OVERLAY)
 
-		lizard_with_snout = icon(lizard)
-		lizard_with_snout.Blend(icon('icons/mob/human/species/lizard/lizard_misc.dmi', "m_snout_round_ADJ", EAST), ICON_OVERLAY)
+		lizard_with_snout = lizard.copy()
+		lizard_with_snout.blend_icon(uni_icon('icons/mob/human/species/lizard/lizard_misc.dmi', "m_snout_round_ADJ", EAST), ICON_OVERLAY)
 
-	var/icon/final_icon = include_snout ? icon(lizard_with_snout) : icon(lizard)
+	var/datum/universal_icon/final_icon = include_snout ? lizard_with_snout.copy() : lizard.copy()
 
-	if (!isnull(sprite_accessory))
-		var/icon/accessory_icon = icon(sprite_accessory.icon, "m_[key]_[sprite_accessory.icon_state]_ADJ", EAST)
-		final_icon.Blend(accessory_icon, ICON_OVERLAY)
+	if (!isnull(sprite_accessory) && sprite_accessory.icon_state != SPRITE_ACCESSORY_NONE)
+		var/datum/universal_icon/accessory_icon = uni_icon(sprite_accessory.icon, "m_[key]_[sprite_accessory.icon_state]_ADJ", EAST)
+		final_icon.blend_icon(accessory_icon, ICON_OVERLAY)
 
-	final_icon.Crop(11, 20, 23, 32)
-	final_icon.Scale(32, 32)
-	final_icon.Blend(COLOR_VIBRANT_LIME, ICON_MULTIPLY)
+	final_icon.crop(11, 20, 23, 32)
+	final_icon.scale(32, 32)
+	final_icon.blend_color(COLOR_VIBRANT_LIME, ICON_MULTIPLY)
 
 	return final_icon
 
@@ -37,20 +37,20 @@
 /datum/preference/choiced/lizard_body_markings/icon_for(value)
 	var/datum/sprite_accessory/sprite_accessory = SSaccessories.lizard_markings_list[value]
 
-	var/icon/final_icon = icon('icons/mob/human/species/lizard/bodyparts.dmi', "lizard_chest_m")
+	var/datum/universal_icon/final_icon = uni_icon('icons/mob/human/species/lizard/bodyparts.dmi', "lizard_chest_m")
 
-	if (sprite_accessory.icon_state != "none")
-		var/icon/body_markings_icon = icon(
-			'icons/mob/human/species/lizard/lizard_misc.dmi',
+	if (sprite_accessory.icon_state != SPRITE_ACCESSORY_NONE)
+		var/datum/universal_icon/body_markings_icon = uni_icon(
+			sprite_accessory.icon,
 			"male_[sprite_accessory.icon_state]_chest",
 		)
 
-		final_icon.Blend(body_markings_icon, ICON_OVERLAY)
+		final_icon.blend_icon(body_markings_icon, ICON_OVERLAY)
 
-	final_icon.Blend(COLOR_VIBRANT_LIME, ICON_MULTIPLY)
-	final_icon.Crop(10, 8, 22, 23)
-	final_icon.Scale(26, 32)
-	final_icon.Crop(-2, 1, 29, 32)
+	final_icon.blend_color(COLOR_VIBRANT_LIME, ICON_MULTIPLY)
+	final_icon.crop(10, 8, 22, 23)
+	final_icon.scale(26, 32)
+	final_icon.crop(-2, 1, 29, 32)
 
 	return final_icon
 

code/modules/client/preferences/species_features/moth.dm

@@ -9,19 +9,19 @@
 	return assoc_to_keys_features(SSaccessories.moth_antennae_list)
 
 /datum/preference/choiced/moth_antennae/icon_for(value)
-	var/static/icon/moth_head
+	var/static/datum/universal_icon/moth_head
 
 	if (isnull(moth_head))
-		moth_head = icon('icons/mob/human/species/moth/bodyparts.dmi', "moth_head")
-		moth_head.Blend(icon('icons/mob/human/human_face.dmi', "motheyes_l"), ICON_OVERLAY)
-		moth_head.Blend(icon('icons/mob/human/human_face.dmi', "motheyes_r"), ICON_OVERLAY)
+		moth_head = uni_icon('icons/mob/human/species/moth/bodyparts.dmi', "moth_head")
+		moth_head.blend_icon(uni_icon('icons/mob/human/human_face.dmi', "motheyes_l"), ICON_OVERLAY)
+		moth_head.blend_icon(uni_icon('icons/mob/human/human_face.dmi', "motheyes_r"), ICON_OVERLAY)
 
 	var/datum/sprite_accessory/antennae = SSaccessories.moth_antennae_list[value]
 
-	var/icon/icon_with_antennae = new(moth_head)
-	icon_with_antennae.Blend(icon(antennae.icon, "m_moth_antennae_[antennae.icon_state]_FRONT"), ICON_OVERLAY)
-	icon_with_antennae.Scale(64, 64)
-	icon_with_antennae.Crop(15, 64, 15 + 31, 64 - 31)
+	var/datum/universal_icon/icon_with_antennae = moth_head.copy()
+	icon_with_antennae.blend_icon(uni_icon(antennae.icon, "m_moth_antennae_[antennae.icon_state]_FRONT"), ICON_OVERLAY)
+	icon_with_antennae.scale(64, 64)
+	icon_with_antennae.crop(15, 64 - 31, 15 + 31, 64)
 
 	return icon_with_antennae
 
@@ -47,33 +47,31 @@
 		/obj/item/bodypart/arm/right/moth,
 	)
 
-	var/static/icon/moth_body
+	var/static/datum/universal_icon/moth_body
 	if (isnull(moth_body))
-		moth_body = icon('icons/blanks/32x32.dmi', "nothing")
-
-		moth_body.Blend(icon('icons/mob/human/species/moth/moth_wings.dmi', "m_moth_wings_plain_BEHIND"), ICON_OVERLAY)
+		moth_body = uni_icon('icons/blanks/32x32.dmi', "nothing")
 
 		for (var/obj/item/bodypart/body_part as anything in body_parts)
-			moth_body.Blend(icon('icons/mob/human/species/moth/bodyparts.dmi', initial(body_part.icon_state)), ICON_OVERLAY)
+			moth_body.blend_icon(uni_icon('icons/mob/human/species/moth/bodyparts.dmi', initial(body_part.icon_state)), ICON_OVERLAY)
 
-		moth_body.Blend(icon('icons/mob/human/human_face.dmi', "motheyes_l"), ICON_OVERLAY)
-		moth_body.Blend(icon('icons/mob/human/human_face.dmi', "motheyes_r"), ICON_OVERLAY)
+		moth_body.blend_icon(uni_icon('icons/mob/human/human_face.dmi', "motheyes_l"), ICON_OVERLAY)
+		moth_body.blend_icon(uni_icon('icons/mob/human/human_face.dmi', "motheyes_r"), ICON_OVERLAY)
 
 	var/datum/sprite_accessory/markings = SSaccessories.moth_markings_list[value]
-	var/icon/icon_with_markings = new(moth_body)
+	var/datum/universal_icon/icon_with_markings = moth_body.copy()
 
-	if (value != "None")
+	if (value != SPRITE_ACCESSORY_NONE)
 		for (var/obj/item/bodypart/body_part as anything in body_parts)
-			var/icon/body_part_icon = icon(markings.icon, "[markings.icon_state]_[initial(body_part.body_zone)]")
-			body_part_icon.Crop(1, 1, 32, 32)
-			icon_with_markings.Blend(body_part_icon, ICON_OVERLAY)
+			var/datum/universal_icon/body_part_icon = uni_icon(markings.icon, "[markings.icon_state]_[initial(body_part.body_zone)]")
+			body_part_icon.crop(1, 1, 32, 32)
+			icon_with_markings.blend_icon(body_part_icon, ICON_OVERLAY)
 
-	icon_with_markings.Blend(icon('icons/mob/human/species/moth/moth_wings.dmi', "m_moth_wings_plain_FRONT"), ICON_OVERLAY)
-	icon_with_markings.Blend(icon('icons/mob/human/species/moth/moth_antennae.dmi', "m_moth_antennae_plain_FRONT"), ICON_OVERLAY)
+	icon_with_markings.blend_icon(uni_icon('icons/mob/human/species/moth/moth_wings.dmi', "m_moth_wings_plain_FRONT"), ICON_OVERLAY)
+	icon_with_markings.blend_icon(uni_icon('icons/mob/human/species/moth/moth_antennae.dmi', "m_moth_antennae_plain_FRONT"), ICON_OVERLAY)
 
 	// Zoom in on the top of the head and the chest
-	icon_with_markings.Scale(64, 64)
-	icon_with_markings.Crop(15, 64, 15 + 31, 64 - 31)
+	icon_with_markings.scale(64, 64)
+	icon_with_markings.crop(15, 64 - 31, 15 + 31, 64)
 
 	return icon_with_markings
 
@@ -92,9 +90,7 @@
 
 /datum/preference/choiced/moth_wings/icon_for(value)
 	var/datum/sprite_accessory/moth_wings = SSaccessories.moth_wings_list[value]
-	var/icon/final_icon = icon(moth_wings.icon, "m_moth_wings_[moth_wings.icon_state]_BEHIND")
-	final_icon.Blend(icon(moth_wings.icon, "m_moth_wings_[moth_wings.icon_state]_FRONT"), ICON_OVERLAY)
-	return final_icon
+	return uni_icon(moth_wings.icon, "m_moth_wings_[moth_wings.icon_state]_BEHIND")
 
 /datum/preference/choiced/moth_wings/apply_to_human(mob/living/carbon/human/target, value)
 	target.dna.features["moth_wings"] = value

code/modules/client/preferences/species_features/pod.dm

@@ -11,15 +11,15 @@
 /datum/preference/choiced/pod_hair/icon_for(value)
 	var/datum/sprite_accessory/pod_hair = SSaccessories.pod_hair_list[value]
 
-	var/icon/icon_with_hair = icon('icons/mob/human/bodyparts_greyscale.dmi', "pod_head_m")
+	var/datum/universal_icon/icon_with_hair = uni_icon('icons/mob/human/bodyparts_greyscale.dmi', "pod_head_m")
 
-	var/icon/icon_adj = icon(pod_hair.icon, "m_pod_hair_[pod_hair.icon_state]_ADJ")
-	var/icon/icon_front = icon(pod_hair.icon, "m_pod_hair_[pod_hair.icon_state]_FRONT")
-	icon_adj.Blend(icon_front, ICON_OVERLAY)
-	icon_with_hair.Blend(icon_adj, ICON_OVERLAY)
-	icon_with_hair.Scale(64, 64)
-	icon_with_hair.Crop(15, 64, 15 + 31, 64 - 31)
-	icon_with_hair.Blend(COLOR_GREEN, ICON_MULTIPLY)
+	var/datum/universal_icon/icon_adj = uni_icon(pod_hair.icon, "m_pod_hair_[pod_hair.icon_state]_ADJ")
+	var/datum/universal_icon/icon_front = uni_icon(pod_hair.icon, "m_pod_hair_[pod_hair.icon_state]_FRONT")
+	icon_adj.blend_icon(icon_front, ICON_OVERLAY)
+	icon_with_hair.blend_icon(icon_adj, ICON_OVERLAY)
+	icon_with_hair.scale(64, 64)
+	icon_with_hair.crop(15, 64 - 31, 15 + 31, 64)
+	icon_with_hair.blend_color(COLOR_GREEN, ICON_MULTIPLY)
 
 	return icon_with_hair
 

code/modules/client/preferences/species_features/vampire.dm

@@ -16,9 +16,9 @@
 /datum/preference/choiced/vampire_status/icon_for(value)
 	switch (value)
 		if ("Inoculated")
-			return icon('icons/obj/drinks/drinks.dmi', "bloodglass")
+			return uni_icon('icons/obj/drinks/drinks.dmi', "bloodglass")
 		if ("Outcast")
-			return icon('icons/obj/medical/bloodpack.dmi', "generic_bloodpack")
+			return uni_icon('icons/obj/medical/bloodpack.dmi', "generic_bloodpack")
 
 ///list that stores a vampire house name for each department
 GLOBAL_LIST_EMPTY(vampire_houses)

code/modules/client/preferences/ui_style.dm

@@ -9,11 +9,11 @@
 	return assoc_to_keys(GLOB.available_ui_styles)
 
 /datum/preference/choiced/ui_style/icon_for(value)
-	var/icon/icons = GLOB.available_ui_styles[value]
+	var/ui_icons = GLOB.available_ui_styles[value]
 
-	var/icon/icon = icon(icons, "hand_r")
-	icon.Crop(1, 1, ICON_SIZE_X * 2, ICON_SIZE_Y)
-	icon.Blend(icon(icons, "hand_l"), ICON_OVERLAY, ICON_SIZE_X)
+	var/datum/universal_icon/icon = uni_icon(ui_icons, "hand_l")
+	icon.crop(1 - ICON_SIZE_X, 1, ICON_SIZE_Y, ICON_SIZE_X)
+	icon.blend_icon(uni_icon(ui_icons, "hand_r"), ICON_OVERLAY)
 
 	return icon
 

code/modules/client/verbs/ooc.dm

@@ -82,7 +82,7 @@ GLOBAL_VAR_INIT(normal_ooc_colour, "#002eb8")
 		if(prefs.toggles & MEMBER_PUBLIC)
 			keyname = "<font color='[prefs.read_preference(/datum/preference/color/ooc_color) || GLOB.normal_ooc_colour]'>[icon2html('icons/ui/chat/member_content.dmi', world, "blag")][keyname]</font>"
 	if(prefs.hearted)
-		var/datum/asset/spritesheet/sheet = get_asset_datum(/datum/asset/spritesheet/chat)
+		var/datum/asset/spritesheet_batched/sheet = get_asset_datum(/datum/asset/spritesheet_batched/chat)
 		keyname = "[sheet.icon_tag("emoji-heart")][keyname]"
 	//The linkify span classes and linkify=TRUE below make ooc text get clickable chat href links if you pass in something resembling a url
 	for(var/client/receiver as anything in GLOB.clients)

code/modules/emoji/emoji_parse.dm

@@ -17,7 +17,7 @@
 			search = findtext(text, ":", pos + length(text[pos]))
 			if(search)
 				emoji = LOWER_TEXT(copytext(text, pos + length(text[pos]), search))
-				var/datum/asset/spritesheet/sheet = get_asset_datum(/datum/asset/spritesheet/chat)
+				var/datum/asset/spritesheet_batched/sheet = get_asset_datum(/datum/asset/spritesheet_batched/chat)
 				var/tag = sheet.icon_tag("emoji-[emoji]")
 				if(tag)
 					parsed += tag

code/modules/fishing/fish_catalog.dm

@@ -111,5 +111,5 @@
 
 /obj/item/book/manual/fish_catalog/ui_assets(mob/user)
 	return list(
-		get_asset_datum(/datum/asset/spritesheet/fish)
+		get_asset_datum(/datum/asset/spritesheet_batched/fish)
 	)

code/modules/hydroponics/biogenerator.dm

@@ -465,7 +465,7 @@
 
 /obj/machinery/biogenerator/ui_assets(mob/user)
 	return list(
-		get_asset_datum(/datum/asset/spritesheet/research_designs),
+		get_asset_datum(/datum/asset/spritesheet_batched/research_designs),
 	)
 
 

code/modules/hydroponics/seed_extractor.dm

@@ -311,5 +311,5 @@
 
 /obj/machinery/seed_extractor/ui_assets(mob/user)
 	return list(
-		get_asset_datum(/datum/asset/spritesheet/seeds)
+		get_asset_datum(/datum/asset/spritesheet_batched/seeds)
 	)

code/modules/language/_language.dm

@@ -56,7 +56,7 @@
 
 /// Returns the icon to display in the chat window when speaking this language.
 /datum/language/proc/get_icon()
-	var/datum/asset/spritesheet/sheet = get_asset_datum(/datum/asset/spritesheet/chat)
+	var/datum/asset/spritesheet_batched/sheet = get_asset_datum(/datum/asset/spritesheet_batched/chat)
 	return sheet.icon_tag("language-[icon_state]")
 
 /// Simple helper for getting a default firstname lastname

code/modules/library/lib_machines.dm

@@ -406,7 +406,7 @@ GLOBAL_VAR_INIT(library_table_modified, 0)
 	return data
 
 /obj/machinery/computer/libraryconsole/bookmanagement/ui_assets(mob/user)
-	return list(get_asset_datum(/datum/asset/spritesheet/bibles))
+	return list(get_asset_datum(/datum/asset/spritesheet_batched/bibles))
 
 /obj/machinery/computer/libraryconsole/bookmanagement/proc/load_nearby_books()
 	for(var/datum/book_info/book as anything in SSlibrary.get_area_books(get_area(src)))

code/modules/mafia/controller_ui.dm

@@ -77,7 +77,7 @@
 
 /datum/mafia_controller/ui_assets(mob/user)
 	return list(
-		get_asset_datum(/datum/asset/spritesheet/mafia),
+		get_asset_datum(/datum/asset/spritesheet_batched/mafia),
 	)
 
 /datum/mafia_controller/ui_act(action, list/params, datum/tgui/ui, datum/ui_state/state)

code/modules/mining/machine_silo.dm

@@ -98,7 +98,7 @@
 
 /obj/machinery/ore_silo/ui_assets(mob/user)
 	return list(
-		get_asset_datum(/datum/asset/spritesheet/sheetmaterials)
+		get_asset_datum(/datum/asset/spritesheet_batched/sheetmaterials)
 	)
 
 /obj/machinery/ore_silo/ui_interact(mob/user, datum/tgui/ui)

code/modules/modular_computers/file_system/programs/emojipedia.dm

@@ -27,5 +27,5 @@
 
 /datum/computer_file/program/emojipedia/ui_assets(mob/user)
 	return list(
-		get_asset_datum(/datum/asset/spritesheet/emojipedia),
+		get_asset_datum(/datum/asset/spritesheet_batched/emojipedia),
 	)

code/modules/modular_computers/file_system/programs/messenger/messenger_program.dm

@@ -385,7 +385,7 @@
 
 /datum/computer_file/program/messenger/ui_assets(mob/user)
 	. = ..()
-	. += get_asset_datum(/datum/asset/spritesheet/chat)
+	. += get_asset_datum(/datum/asset/spritesheet_batched/chat)
 
 //////////////////////
 // MESSAGE HANDLING //

code/modules/modular_computers/file_system/programs/techweb.dm

@@ -39,7 +39,7 @@
 
 /datum/computer_file/program/science/ui_assets(mob/user)
 	return list(
-		get_asset_datum(/datum/asset/spritesheet/research_designs)
+		get_asset_datum(/datum/asset/spritesheet_batched/research_designs)
 	)
 
 // heavy data from this proc should be moved to static data when possible
@@ -167,7 +167,7 @@
 
 	// Build design cache
 	var/design_cache = list()
-	var/datum/asset/spritesheet/research_designs/spritesheet = get_asset_datum(/datum/asset/spritesheet/research_designs)
+	var/datum/asset/spritesheet_batched/research_designs/spritesheet = get_asset_datum(/datum/asset/spritesheet_batched/research_designs)
 	var/size32x32 = "[spritesheet.name]32x32"
 	for (var/design_id in SSresearch.techweb_designs)
 		var/datum/design/design = SSresearch.techweb_designs[design_id] || SSresearch.error_design

code/modules/paperwork/stamps.dm

@@ -20,7 +20,7 @@
 	return OXYLOSS
 
 /obj/item/stamp/get_writing_implement_details()
-	var/datum/asset/spritesheet/sheet = get_asset_datum(/datum/asset/spritesheet/simple/paper)
+	var/datum/asset/spritesheet_batched/sheet = get_asset_datum(/datum/asset/spritesheet/simple/paper)
 	return list(
 		interaction_mode = MODE_STAMPING,
 		stamp_icon_state = icon_state,

code/modules/plumbing/plumbers/pill_press.dm

@@ -28,7 +28,7 @@
 	. = ..()
 
 	if(!packaging_types)
-		var/datum/asset/spritesheet/simple/assets = get_asset_datum(/datum/asset/spritesheet/chemmaster)
+		var/datum/asset/spritesheet_batched/assets = get_asset_datum(/datum/asset/spritesheet_batched/chemmaster)
 
 		var/list/types = list(
 			CAT_PILLS = GLOB.reagent_containers[CAT_PILLS],
@@ -100,7 +100,7 @@
 
 /obj/machinery/plumbing/pill_press/ui_assets(mob/user)
 	return list(
-		get_asset_datum(/datum/asset/spritesheet/chemmaster)
+		get_asset_datum(/datum/asset/spritesheet_batched/chemmaster)
 	)
 
 /obj/machinery/plumbing/pill_press/ui_interact(mob/user, datum/tgui/ui)

code/modules/research/designs.dm

@@ -78,7 +78,7 @@ other types of metals and chemistry for reagents).
 	materials = temp_list
 
 /datum/design/proc/icon_html(client/user)
-	var/datum/asset/spritesheet/sheet = get_asset_datum(/datum/asset/spritesheet/research_designs)
+	var/datum/asset/spritesheet_batched/sheet = get_asset_datum(/datum/asset/spritesheet_batched/research_designs)
 	sheet.send(user)
 	return sheet.icon_tag(id)
 

code/modules/research/machinery/_production.dm

@@ -224,8 +224,8 @@
 
 /obj/machinery/rnd/production/ui_assets(mob/user)
 	return list(
-		get_asset_datum(/datum/asset/spritesheet/sheetmaterials),
-		get_asset_datum(/datum/asset/spritesheet/research_designs)
+		get_asset_datum(/datum/asset/spritesheet_batched/sheetmaterials),
+		get_asset_datum(/datum/asset/spritesheet_batched/research_designs)
 	)
 
 /obj/machinery/rnd/production/ui_interact(mob/user, datum/tgui/ui)
@@ -239,7 +239,7 @@
 
 	var/list/designs = list()
 
-	var/datum/asset/spritesheet/research_designs/spritesheet = get_asset_datum(/datum/asset/spritesheet/research_designs)
+	var/datum/asset/spritesheet_batched/research_designs/spritesheet = get_asset_datum(/datum/asset/spritesheet_batched/research_designs)
 	var/size32x32 = "[spritesheet.name]32x32"
 
 	var/coefficient

code/modules/research/rdconsole.dm

@@ -176,7 +176,7 @@ Nothing else in the console has ID requirements.
 
 /obj/machinery/computer/rdconsole/ui_assets(mob/user)
 	return list(
-		get_asset_datum(/datum/asset/spritesheet/research_designs),
+		get_asset_datum(/datum/asset/spritesheet_batched/research_designs),
 	)
 
 // heavy data from this proc should be moved to static data when possible
@@ -300,7 +300,7 @@ Nothing else in the console has ID requirements.
 
 	// Build design cache
 	var/design_cache = list()
-	var/datum/asset/spritesheet/research_designs/spritesheet = get_asset_datum(/datum/asset/spritesheet/research_designs)
+	var/datum/asset/spritesheet_batched/research_designs/spritesheet = get_asset_datum(/datum/asset/spritesheet_batched/research_designs)
 	var/size32x32 = "[spritesheet.name]32x32"
 	for (var/design_id in SSresearch.techweb_designs)
 		var/datum/design/design = SSresearch.techweb_designs[design_id] || SSresearch.error_design

code/modules/tgui/tgui_window.dm

@@ -313,6 +313,9 @@
 	if(istype(asset, /datum/asset/spritesheet))
 		var/datum/asset/spritesheet/spritesheet = asset
 		send_message("asset/stylesheet", spritesheet.css_filename())
+	else if(istype(asset, /datum/asset/spritesheet_batched))
+		var/datum/asset/spritesheet_batched/spritesheet = asset
+		send_message("asset/stylesheet", spritesheet.css_filename())
 	send_raw_message(asset.get_serialized_url_mappings())
 
 /**

code/modules/tgui_panel/tgui_panel.dm

@@ -49,7 +49,7 @@
 		))
 	window.send_asset(get_asset_datum(/datum/asset/simple/namespaced/fontawesome))
 	window.send_asset(get_asset_datum(/datum/asset/simple/namespaced/tgfont))
-	window.send_asset(get_asset_datum(/datum/asset/spritesheet/chat))
+	window.send_asset(get_asset_datum(/datum/asset/spritesheet_batched/chat))
 	// Other setup
 	request_telemetry()
 	addtimer(CALLBACK(src, PROC_REF(on_initialize_timed_out)), 5 SECONDS)

code/modules/transport/tram/tram_doors.dm

@@ -10,6 +10,7 @@
 	multi_tile = TRUE
 	opacity = FALSE
 	assemblytype = /obj/structure/door_assembly/multi_tile/door_assembly_tram
+	can_be_glass = FALSE
 	airlock_material = "glass"
 	air_tight = TRUE
 	req_access = list(ACCESS_TCOMMS)

code/modules/unit_tests/_unit_tests.dm

@@ -96,6 +96,7 @@
 #include "antag_moodlets.dm"
 #include "area_contents.dm"
 #include "armor_verification.dm"
+#include "asset_smart_cache.dm"
 #include "atmospherics_sanity.dm"
 #include "autowiki.dm"
 #include "bake_a_cake.dm"

code/modules/unit_tests/asset_smart_cache.dm

@@ -0,0 +1,65 @@
+/datum/asset/spritesheet_batched/test
+	name = "test"
+	load_immediately = TRUE
+	force_cache = TRUE
+	// Don't let the asset subsystem load this. This is how we trick it.
+	_abstract = /datum/asset/spritesheet_batched/test
+	var/static/list/items = list(/obj/item/binoculars, /obj/item/camera, /obj/item/clothing/under/color/blue, /obj/item/clothing/under/color/black)
+
+/datum/asset/spritesheet_batched/test/create_spritesheets()
+	for(var/atom/item as anything in items)
+		if (!ispath(item, /atom))
+			return FALSE
+		var/imgid = replacetext(replacetext("[item]", "/obj/item/", ""), "/", "-")
+		insert_icon(imgid, get_display_icon_for(item))
+	// Get some coverage on each operation.
+	var/datum/universal_icon/I = uni_icon('icons/effects/effects.dmi', "nothing")
+	I.blend_icon(uni_icon('icons/effects/effects.dmi', "sparks"), ICON_OVERLAY)
+	I.blend_color("#ff0000", ICON_MULTIPLY)
+	I.scale(64, 64)
+	I.crop(1, 1, 128, 64) // we'll test for the scale later.
+	insert_icon("test", I)
+
+/datum/asset/spritesheet_batched/test/unregister()
+	SSassets.transport.unregister_asset("spritesheet_[name].css")
+	if(length(sizes))
+		for(var/size_id in sizes)
+			SSassets.transport.unregister_asset("[name]_[size_id].png")
+
+/datum/unit_test/test_asset_smart_cache/Run()
+	fdel("[ASSET_CROSS_ROUND_SMART_CACHE_DIRECTORY]/spritesheet_cache.test.json")
+	fdel("data/spritesheets/spritesheet_test.css")
+	var/datum/asset/spritesheet_batched/test/sheet = new()
+	TEST_ASSERT(sheet.fully_generated, "Spritesheet not generated!")
+	// Cache should be invalid initially.
+	TEST_ASSERT(sheet.cache_result, "Spritesheet smart cache was VALID when it should be INVALID!")
+	for(var/item in sheet.items)
+		var/imgid = replacetext(replacetext("[item]", "/obj/item/", ""), "/", "-")
+		// All items should be in sprites list.
+		TEST_ASSERT(imgid in sheet.sprites, "Item [item] not present in spritesheet result!")
+	TEST_ASSERT("test" in sheet.sprites, "Item test not present in spritesheet result!")
+	TEST_ASSERT("128x64" in sheet.sizes, "Test icon was not output as 128x64!")
+	// cache wrote properly
+	TEST_ASSERT(fexists("[ASSET_CROSS_ROUND_SMART_CACHE_DIRECTORY]/spritesheet_cache.test.json"), "Smart cache entry did not write!")
+	// Clear it out and get ready to do it again, this time loading from cache
+	sheet.unregister()
+	sheet.entries = list()
+	sheet.sprites = list()
+	sheet.sizes = list()
+	sheet.job_id = null
+	sheet.cache_result = null
+	sheet.cache_data = null
+	sheet.cache_job_id = null
+	sheet.fully_generated = FALSE
+
+	sheet.register()
+	TEST_ASSERT(sheet.fully_generated, "Spritesheet did not load from smart cache properly!")
+	// Check for CACHE_VALID
+	TEST_ASSERT(!sheet.cache_result, "Spritesheet did not load from smart cache, it was invalid despite having the same input data!")
+	// Cleanup files.
+	fdel("[ASSET_CROSS_ROUND_SMART_CACHE_DIRECTORY]/spritesheet_cache.test.json")
+	fdel("data/spritesheets/spritesheet_test.css")
+	for(var/size in sheet.sizes)
+		fdel("data/spritesheets/test_[size].png")
+
+

code/modules/unit_tests/preferences.dm

@@ -65,7 +65,7 @@
 		if (choiced_preference.should_generate_icons)
 			for (var/value in values)
 				var/icon = choiced_preference.icon_for(value)
-				TEST_ASSERT(istype(icon, /icon) || ispath(icon), "[preference_type] gave [icon] as an icon for [value], which is not a valid value")
+				TEST_ASSERT(istype(icon, /datum/universal_icon) || ispath(icon), "[preference_type] gave [icon] as an icon for [value], which is not a valid value")
 		else
 			var/errored = FALSE
 

code/modules/unit_tests/spritesheets.dm

@@ -5,6 +5,19 @@
 	for(var/datum/asset/spritesheet/sheet as anything in subtypesof(/datum/asset/spritesheet))
 		if(!initial(sheet.name)) //Ignore abstract types
 			continue
+		if (sheet == initial(sheet._abstract))
+			continue
+		sheet = get_asset_datum(sheet)
+		for(var/sprite_name in sheet.sprites)
+			if(!sprite_name)
+				TEST_FAIL("Spritesheet [sheet.type] has a nameless icon state.")
+
+	// Test IconForge generated sheets as well
+	for(var/datum/asset/spritesheet_batched/sheet as anything in subtypesof(/datum/asset/spritesheet_batched))
+		if(!initial(sheet.name)) //Ignore abstract types
+			continue
+		if (sheet == initial(sheet._abstract))
+			continue
 		sheet = get_asset_datum(sheet)
 		for(var/sprite_name in sheet.sprites)
 			if(!sprite_name)

code/modules/vehicles/mecha/mech_fabricator.dm

@@ -367,8 +367,8 @@
 
 /obj/machinery/mecha_part_fabricator/ui_assets(mob/user)
 	return list(
-		get_asset_datum(/datum/asset/spritesheet/sheetmaterials),
-		get_asset_datum(/datum/asset/spritesheet/research_designs)
+		get_asset_datum(/datum/asset/spritesheet_batched/sheetmaterials),
+		get_asset_datum(/datum/asset/spritesheet_batched/research_designs)
 	)
 
 /obj/machinery/mecha_part_fabricator/ui_interact(mob/user, datum/tgui/ui)
@@ -382,7 +382,7 @@
 
 	var/list/designs = list()
 
-	var/datum/asset/spritesheet/research_designs/spritesheet = get_asset_datum(/datum/asset/spritesheet/research_designs)
+	var/datum/asset/spritesheet_batched/research_designs/spritesheet = get_asset_datum(/datum/asset/spritesheet_batched/research_designs)
 	var/size32x32 = "[spritesheet.name]32x32"
 
 	for(var/datum/design/design in cached_designs)

code/modules/vehicles/mecha/mecha_ui.dm

@@ -29,7 +29,7 @@
 
 /obj/vehicle/sealed/mecha/ui_assets(mob/user)
 	return list(
-		get_asset_datum(/datum/asset/spritesheet/mecha_equipment),
+		get_asset_datum(/datum/asset/spritesheet_batched/mecha_equipment),
 	)
 
 /obj/vehicle/sealed/mecha/ui_static_data(mob/user)