Extends atom_reskin to be more modular/adds support for greyscale reskins in the loadout menu (#94466)

Co-authored-by: SmArtKar <44720187+SmArtKar@users.noreply.github.com>

code/controllers/subsystem/greyscale_previews.dm

@@ -16,13 +16,76 @@ SUBSYSTEM_DEF(greyscale_previews)
 	if(!CONFIG_GET(flag/generate_assets_in_init))
 		return SS_INIT_SUCCESS
 #endif
-
 	ExportMapPreviews()
 	return SS_INIT_SUCCESS
 
+/// Sets up the list of types to process for organizing icons into their respective .dmi.
+/datum/controller/subsystem/greyscale_previews/proc/build_type_category_map(list/types_that_get_their_own_file)
+	var/list/type_to_filename = list()
+
+	for (var/filename in types_that_get_their_own_file)
+		var/root = types_that_get_their_own_file[filename]
+
+		for (var/atom/atom_type as anything in typesof(root))
+			// First match wins (prevents /obj from overwriting clothing buckets, etc.)
+			if (isnull(type_to_filename[atom_type]))
+				type_to_filename[atom_type] = filename
+
+	return type_to_filename
+
+/// Builds a worklist of all the item types to try making a GAGS preview icon for.
+/datum/controller/subsystem/greyscale_previews/proc/build_preview_worklists(list/types_that_get_their_own_file)
+	var/list/type_to_filename = build_type_category_map(types_that_get_their_own_file)
+
+	/// filename => list(entries)
+	var/list/worklists = list()
+
+	for (var/filename in types_that_get_their_own_file)
+		worklists[filename] = list()
+
+	worklists["unsorted"] = list()
+
+	/// ---- atom skins ----
+	for (var/skin_path, atom_skin in get_atom_skins())
+		var/datum/atom_skin/skin = atom_skin
+		var/atom/typepath = skin.greyscale_item_path
+		if (!GLOB.all_loadout_datums[typepath]) // We don't need reskin previews for non-loadout items
+			continue
+		if (isnull(skin.new_icon_state)) // This is the same as the default icon, which we will be generating below.
+			continue
+		if (!typepath::greyscale_config || !typepath::greyscale_colors)
+			continue
+		if (typepath::flags_1 & NO_NEW_GAGS_PREVIEW_1)
+			continue
+
+		var/filename = type_to_filename[typepath] || "unsorted"
+		worklists[filename] += skin
+
+	var/list/seen_typepaths = list()
+	/// ---- base atom types ----
+	for (var/filename, path in types_that_get_their_own_file)
+		var/atom/root = path
+		var/list/filename_worklist = worklists[filename]
+
+		for (var/atom/typepath as anything in valid_typesof(root))
+			if (seen_typepaths[typepath])
+				continue
+
+			seen_typepaths[typepath] = TRUE
+
+			if (!typepath::greyscale_config || !typepath::greyscale_colors)
+				continue
+			if (typepath::flags_1 & NO_NEW_GAGS_PREVIEW_1)
+				continue
+
+			filename_worklist += typepath
+
+	return worklists
+
+/// Goes through all the valid GAGS item types in subtypes that fall under the types specified in types_that_get_their_own_file, creating a .dmi for each.
 /datum/controller/subsystem/greyscale_previews/proc/ExportMapPreviews()
 	// Put subtypes before their parent or the parent file will take all the generated icons
-	var/static/list/types_that_get_their_own_file = list(
+	var/list/types_that_get_their_own_file = list(
 		"turfs" = /turf, // None of these yet but it's harmless to be prepared
 		"mobs" = /mob, // Ditto
 		"clothing/accessory" = /obj/item/clothing/accessory,
@@ -45,27 +108,23 @@ SUBSYSTEM_DEF(greyscale_previews)
 )
 
 #ifdef UNIT_TESTS
-	if(!check_map_previews_filepath_order(types_that_get_their_own_file))
+	if (!check_map_previews_filepath_order(types_that_get_their_own_file))
 		CRASH("The list 'types_that_get_their_own_file', used by ExportMapPreviews, is invalid. Please ensure that subtypes come BEFORE parent types in the list order.")
 #endif
-
-	var/list/handled_types = list()
-	for(var/filename in types_that_get_their_own_file)
-		var/type_to_export = types_that_get_their_own_file[filename]
-		handled_types += ExportMapPreviewsForType(filename, type_to_export, handled_types)
-
-	ExportMapPreviewsForType("unsorted", /atom, handled_types)
+	var/list/worklists = build_preview_worklists(types_that_get_their_own_file)
+	for (var/filename in worklists)
+		ExportMapPreviewsForType(filename, worklists[filename])
 
 /// Checks that we do not have any parent types coming before subtypes in the types_that_get_their_own_file list (which is an assoc list (filepath, typepath))
 /datum/controller/subsystem/greyscale_previews/proc/check_map_previews_filepath_order(list/our_list)
 	var/list/type_paths_to_check = list()
-	for(var/filepath in our_list)
+	for (var/filepath in our_list)
 		type_paths_to_check += our_list[filepath]
 
-	if(!length(type_paths_to_check))
+	if (!length(type_paths_to_check))
 		return TRUE
 
-	for(var/i = 1 to length(type_paths_to_check))
+	for (var/i = 1 to length(type_paths_to_check))
 		var/path_i = type_paths_to_check[i]
 		for(var/j = i+1 to length(type_paths_to_check))
 			var/path_j = type_paths_to_check[j]
@@ -74,31 +133,49 @@ SUBSYSTEM_DEF(greyscale_previews)
 				return FALSE
 	return TRUE
 
-/datum/controller/subsystem/greyscale_previews/proc/ExportMapPreviewsForType(filename, atom/atom_typepath, list/type_blacklist)
-	var/list/handled_types = list()
+/datum/controller/subsystem/greyscale_previews/proc/ExportMapPreviewsForType(filename, list/entries)
 	var/list/icons = list()
-	for(var/atom/atom_type as anything in typesof(atom_typepath))
-		if(type_blacklist && type_blacklist[atom_type])
+
+	for (var/entry in entries)
+		var/atom/typepath
+		var/icon_state
+		var/reskin_icon_state
+
+		if (istype(entry, /datum/atom_skin))
+			var/datum/atom_skin/skin = entry
+			typepath = skin.greyscale_item_path
+			icon_state = skin.new_icon_state
+			reskin_icon_state = TRUE
+		else
+			typepath = entry
+			icon_state = typepath::post_init_icon_state
+
+		if (!typepath)
 			continue
-		handled_types[atom_type] = TRUE
-		var/greyscale_config = atom_type::greyscale_config
-		var/greyscale_colors = atom_type::greyscale_colors
-		if(!greyscale_config || !greyscale_colors || atom_type::flags_1 & NO_NEW_GAGS_PREVIEW_1)
+
+		var/greyscale_config = typepath::greyscale_config
+		var/greyscale_colors = typepath::greyscale_colors
+
+		if (!greyscale_config || !greyscale_colors || (typepath::flags_1 & NO_NEW_GAGS_PREVIEW_1))
 			continue
+
+		// This is what the actual icon state will be in the map_icon .dmi
+		var/key = reskin_icon_state ? "[typepath]--[icon_state]" : "[typepath]"
+
 	#ifdef CHECK_SPRITESHEET_ICON_VALIDITY
-		var/icon/map_icon = icon(SSgreyscale.GetColoredIconByType(greyscale_config, greyscale_colors))
-		if((map_icon.Height() > 32) || (map_icon.Width() > 32)) // No large icons, use icon_preview and icon_preview_state instead.
-			stack_trace("GAGS configuration is trying to generate a map preview graphic for '[atom_type]', which has a large icon. This is not suppoorted; implement icon_preview instead.")
+		var/icon/map_icon = icon(SSgreyscale.GetColoredIconByType(greyscale_config, greyscale_colors)) // No large icons, use icon_preview and icon_preview_state instead.
+		if (map_icon.Width() > 32 || map_icon.Height() > 32)
+			stack_trace("GAGS configuration is trying to generate a map preview graphic for '[typepath]' (icon state: [icon_state]), which has a large icon. This is not suppoorted; implement icon_preview instead.")
 			continue
-		if(!(atom_type::post_init_icon_state in map_icon.IconStates()))
-			stack_trace("GAGS configuration missing icon state needed to generate map preview graphic for '[atom_type]'. Make sure the right greyscale_config is set up.")
+		if (!(icon_state in map_icon.IconStates()))
+			stack_trace("GAGS configuration missing icon state ([icon_state]) needed to generate map preview graphic for '[typepath]'. Make sure the right greyscale_config is set up.")
 			continue
-		map_icon = icon(map_icon, atom_type::post_init_icon_state)
-		icons["[atom_type]"] = map_icon
+		map_icon = icon(map_icon, icon_state)
+		icons[key] = map_icon
 	#else // will be updated to use iconforge's new .dmi spritesheet generation instead
 		var/icon/map_icon = icon(SSgreyscale.GetColoredIconByType(greyscale_config, greyscale_colors))
-		map_icon = icon(map_icon, atom_type::post_init_icon_state)
-		icons["[atom_type]"] = map_icon
+		map_icon = icon(map_icon, icon_state)
+		icons[map_icon_key] = map_icon
 	#endif
 
 	var/icon/holder = icon('icons/testing/greyscale_error.dmi')
@@ -115,7 +192,6 @@ SUBSYSTEM_DEF(greyscale_previews)
 	if(old_md5 != new_md5)
 		stack_trace("Generated map icons were different than what is currently saved. If you see this in a CI run it means you need to run the game once through initialization and commit the resulting files in 'icons/map_icons/'")
 #endif
-	return handled_types
 
 #ifdef CHECK_SPRITESHEET_ICON_VALIDITY
 	#undef CHECK_SPRITESHEET_ICON_VALIDITY