Turns lighting objects into a datum, makes all lighting be performed with an underlay. big maptick fix very good! (#58991)

credit to zewaka for the idea of using underlays

turns the lighting object movables that were unnecessary and increased maptick into a datum which then applies and removes an underlay in update(). also applies a lot of general lighting clean ups (mostly using as anything in loops and fixing single letter var names).

multiz is a little different by necessity, now only the bottom turf's lighting matters in the brightness of the top turf unlike master where the bottom turf's lighting object is hidden from the vis_contents of the top turf. there are still some kinks to iron out here though, since currently objects suspended in openspace (like tram platforms) look bad and glass floors look bad too

only thing i have left to do is make multiz work (well)

UPDATE: multiz now appears the same as far as i can tell, its possible there are other situations in which its different but datum mats work and it automatically updates if the turf below changes. now i just need to make the system less finnicky if at all possible (and possibly merge managed_turf_vis_content with managed_overlays maybe?)

new update: its basically equivalent to normal multiz as far as i can tell (visually at least, in the circumstances ive tested so far)

NEW NEW UPDATE: turfs no longer have the VIS_HIDE vis_flag and multiz works without stacking the lighting from the floor below! so this shouldnt have any overt drawbacks to master anymore

1 needless movable per tile is terrible for maptick. this is probably a larger improvement than my emissive blocker change in terms of maptick. im guessing we'd get around 0.6 average maptick per player after this where currently we get 0.85 or so

Edit: according to lemon, sybil reached 0.71 maptick per person when tm'd with this

if this is a big enough improvement i might finally be able to get rid of the Gone discord avatar

code/__DEFINES/dcs/signals.dm

@@ -71,7 +71,6 @@
 /// from datum ui_act (usr, action)
 #define COMSIG_UI_ACT "COMSIG_UI_ACT"
 
-
 /// fires on the target datum when an element is attached to it (/datum/element)
 #define COMSIG_ELEMENT_ATTACH "element_attach"
 /// fires on the target datum when an element is attached to it  (/datum/element)

code/__DEFINES/layers.dm

@@ -111,7 +111,7 @@
 #define FRILL_MASK_RENDER_TARGET "*FRILL_MASK_PLANE"
 
 //---------- LIGHTING -------------
-///Normal 1 per turf dynamic lighting objects
+///Normal 1 per turf dynamic lighting underlays
 #define LIGHTING_PLANE 100
 #define LIGHTING_RENDER_TARGET "LIGHT_PLANE"
 

code/__HELPERS/icon_smoothing.dm

@@ -149,7 +149,7 @@ DEFINE_BITFIELD(smoothing_junction, list(
 	return ..()
 
 
-//do not use, use QUEUE_SMOOTH(atom)
+///do not use, use QUEUE_SMOOTH(atom)
 /atom/proc/smooth_icon()
 	smoothing_flags &= ~SMOOTH_QUEUED
 	flags_1 |= HTML_USE_INITAL_ICON_1
@@ -389,7 +389,6 @@ DEFINE_BITFIELD(smoothing_junction, list(
 									underlay_appearance.icon_state = DEFAULT_UNDERLAY_ICON_STATE
 					underlays = list(underlay_appearance)
 
-
 /turf/open/floor/set_smoothed_icon_state(new_junction)
 	if(broken || burnt)
 		return

code/__HELPERS/radiation.dm

@@ -7,7 +7,6 @@
 		/mob/camera,
 		/obj/effect,
 		/obj/docking_port,
-		/atom/movable/lighting_object,
 		/obj/projectile,
 		))
 	var/list/processing_list = list(location)

code/_onclick/hud/plane_master.dm

@@ -26,9 +26,10 @@
 
 /atom/movable/screen/plane_master/openspace/Initialize()
 	. = ..()
-	add_filter("first_stage_openspace", 1, drop_shadow_filter(color = "#04080FAA", size = -10))
+	add_filter("multiz_lighting_mask", 1, alpha_mask_filter(render_source = LIGHTING_RENDER_TARGET, flags = MASK_INVERSE))
-	add_filter("second_stage_openspace", 2, drop_shadow_filter(color = "#04080FAA", size = -15))
+	add_filter("first_stage_openspace", 2, drop_shadow_filter(color = "#04080FAA", size = -10))
-	add_filter("third_stage_openspace", 2, drop_shadow_filter(color = "#04080FAA", size = -20))
+	add_filter("second_stage_openspace", 3, drop_shadow_filter(color = "#04080FAA", size = -15))
+	add_filter("third_stage_openspace", 4, drop_shadow_filter(color = "#04080FAA", size = -20))
 
 ///Contains just the floor
 /atom/movable/screen/plane_master/floor

code/controllers/subsystem/lighting.dm

@@ -72,7 +72,7 @@ SUBSYSTEM_DEF(lighting)
 
 	queue = objects_queue
 	for (i in 1 to length(queue))
-		var/atom/movable/lighting_object/O = queue[i]
+		var/datum/lighting_object/O = queue[i]
 
 		if (QDELETED(O))
 			continue

code/datums/elements/turf_transparency.dm

@@ -1,3 +1,4 @@
+
 /datum/element/turf_z_transparency
 	var/show_bottom_level = FALSE
 
@@ -19,7 +20,6 @@
 
 	ADD_TRAIT(our_turf, TURF_Z_TRANSPARENT_TRAIT, TURF_TRAIT)
 
-
 	update_multiz(our_turf, TRUE, TRUE)
 
 /datum/element/turf_z_transparency/Detach(datum/source)
@@ -38,6 +38,7 @@
 			return FALSE
 	if(init)
 		our_turf.vis_contents += below_turf
+
 	if(isclosedturf(our_turf)) //Show girders below closed turfs
 		var/mutable_appearance/girder_underlay = mutable_appearance('icons/obj/structures.dmi', "girder", layer = TURF_LAYER-0.01)
 		girder_underlay.appearance_flags = RESET_ALPHA | RESET_COLOR
@@ -47,16 +48,20 @@
 		our_turf.underlays += plating_underlay
 	return TRUE
 
-/datum/element/turf_z_transparency/proc/on_multiz_turf_del(turf/our_turf, turf/T, dir)
+/datum/element/turf_z_transparency/proc/on_multiz_turf_del(turf/our_turf, turf/below_turf, dir)
 	SIGNAL_HANDLER
+
 	if(dir != DOWN)
 		return
+
 	update_multiz(our_turf)
 
-/datum/element/turf_z_transparency/proc/on_multiz_turf_new(turf/our_turf, turf/T, dir)
+/datum/element/turf_z_transparency/proc/on_multiz_turf_new(turf/our_turf, turf/below_turf, dir)
 	SIGNAL_HANDLER
+
 	if(dir != DOWN)
 		return
+
 	update_multiz(our_turf)
 
 ///Called when there is no real turf below this turf

code/game/turfs/change_turf.dm

@@ -6,7 +6,7 @@ GLOBAL_LIST_INIT(blacklisted_automated_baseturfs, typecacheof(list(
 
 /turf/proc/empty(turf_type=/turf/open/space, baseturf_type, list/ignore_typecache, flags)
 	// Remove all atoms except observers, landmarks, docking ports
-	var/static/list/ignored_atoms = typecacheof(list(/mob/dead, /obj/effect/landmark, /obj/docking_port, /atom/movable/lighting_object))
+	var/static/list/ignored_atoms = typecacheof(list(/mob/dead, /obj/effect/landmark, /obj/docking_port))
 	var/list/allowed_contents = typecache_filter_list_reverse(GetAllContentsIgnoring(ignore_typecache), ignored_atoms)
 	allowed_contents -= src
 	for(var/i in 1 to allowed_contents.len)
@@ -23,10 +23,11 @@ GLOBAL_LIST_INIT(blacklisted_automated_baseturfs, typecacheof(list(
 		var/obj/O
 		if(underlays.len) //we have underlays, which implies some sort of transparency, so we want to a snapshot of the previous turf as an underlay
 			O = new()
-			O.underlays.Add(T)
+			O.underlays += T
 		T.ChangeTurf(type)
 		if(underlays.len)
-			T.underlays = O.underlays
+			T.underlays.Cut()
+			T.underlays += O.underlays
 	if(T.icon_state != icon_state)
 		T.icon_state = icon_state
 	if(T.icon != icon)
@@ -128,9 +129,11 @@ GLOBAL_LIST_INIT(blacklisted_automated_baseturfs, typecacheof(list(
 				lighting_build_overlay()
 			else
 				lighting_clear_overlay()
+		else if(lighting_object && !lighting_object.needs_update)
+			lighting_object.update()
 
-		for(var/turf/open/space/S in RANGE_TURFS(1, src)) //RANGE_TURFS is in code\__HELPERS\game.dm
+		for(var/turf/open/space/space_tile in RANGE_TURFS(1, src))
-			S.update_starlight()
+			space_tile.update_starlight()
 
 	QUEUE_SMOOTH_NEIGHBORS(src)
 	QUEUE_SMOOTH(src)

code/game/turfs/open/openspace.dm

@@ -5,17 +5,16 @@ GLOBAL_DATUM_INIT(openspace_backdrop_one_for_all, /atom/movable/openspace_backdr
 
 	anchored = TRUE
 
-	icon            = 'icons/turf/floors.dmi'
+	icon = 'icons/turf/floors.dmi'
-	icon_state      = "grey"
+	icon_state = "grey"
-	plane           = OPENSPACE_BACKDROP_PLANE
+	plane = OPENSPACE_BACKDROP_PLANE
 	mouse_opacity = MOUSE_OPACITY_TRANSPARENT
-	//I don't know why the others are aligned but I shall do the same.
 	vis_flags = VIS_INHERIT_ID
 
 /turf/open/openspace
 	name = "open space"
 	desc = "Watch your step!"
-	icon_state = "transparent"
+	icon_state = "invisible"
 	baseturfs = /turf/open/openspace
 	CanAtmosPassVertical = ATMOS_PASS_YES
 	baseturfs = /turf/open/openspace
@@ -28,7 +27,7 @@ GLOBAL_DATUM_INIT(openspace_backdrop_one_for_all, /atom/movable/openspace_backdr
 	initial_gas_mix = AIRLESS_ATMOS
 
 /turf/open/openspace/airless/planetary
-		planetary_atmos = TRUE
+	planetary_atmos = TRUE
 
 /turf/open/openspace/Initialize() // handle plane and layer here so that they don't cover other obs/turfs in Dream Maker
 	. = ..()

code/game/turfs/turf.dm

@@ -3,7 +3,7 @@ GLOBAL_LIST_EMPTY(station_turfs)
 /// Any floor or wall. What makes up the station and the rest of the map.
 /turf
 	icon = 'icons/turf/floors.dmi'
-	vis_flags = VIS_INHERIT_ID|VIS_INHERIT_PLANE // Important for interaction with and visualization of openspace.
+	vis_flags = VIS_INHERIT_ID | VIS_INHERIT_PLANE// Important for interaction with and visualization of openspace.
 	luminosity = 1
 	/// Turf bitflags, see code/__DEFINES/flags.dm
 	var/turf_flags = NONE
@@ -46,7 +46,7 @@ GLOBAL_LIST_EMPTY(station_turfs)
 	var/tmp/lighting_corners_initialised = FALSE
 
 	///Our lighting object.
-	var/tmp/atom/movable/lighting_object/lighting_object
+	var/tmp/datum/lighting_object/lighting_object
 	///Lighting Corner datums.
 	var/tmp/datum/lighting_corner/lighting_corner_NE
 	var/tmp/datum/lighting_corner/lighting_corner_SE

code/modules/awaymissions/gateway.dm

@@ -355,7 +355,6 @@ GLOBAL_LIST_EMPTY(gateway_destinations)
 	if(!our_destination)
 		return
 
-
 	add_filter("portal_alpha", 1, list("type" = "alpha", "icon" = icon(alpha_icon, alpha_icon_state), "x" = 32, "y" = 32))
 	add_filter("portal_blur", 1, list("type" = "blur", "size" = 0.5))
 	add_filter("portal_ripple", 1, list("type" = "ripple", "size" = 2, "radius" = 1, "falloff" = 1, "y" = 7))
@@ -363,5 +362,4 @@ GLOBAL_LIST_EMPTY(gateway_destinations)
 	animate(get_filter("portal_ripple"), time = 1.3 SECONDS, loop = -1, easing = LINEAR_EASING, radius = 32)
 
 	var/turf/center_turf = our_destination.get_target_turf()
-
 	vis_contents += block(locate(center_turf.x - 1, center_turf.y - 1, center_turf.z), locate(center_turf.x + 1, center_turf.y + 1, center_turf.z))

code/modules/cargo/centcom_podlauncher.dm

@@ -25,7 +25,7 @@
 //Variables declared to change how items in the launch bay are picked and launched. (Almost) all of these are changed in the ui_act proc
 //Some effect groups are choices, while other are booleans. This is because some effects can stack, while others dont (ex: you can stack explosion and quiet, but you cant stack ordered launch and random launch)
 /datum/centcom_podlauncher
-	var/static/list/ignored_atoms = typecacheof(list(null, /mob/dead, /obj/effect/landmark, /obj/docking_port, /atom/movable/lighting_object, /obj/effect/particle_effect/sparks, /obj/effect/pod_landingzone, /obj/effect/hallucination/simple/supplypod_selector,  /obj/effect/hallucination/simple/dropoff_location))
+	var/static/list/ignored_atoms = typecacheof(list(null, /mob/dead, /obj/effect/landmark, /obj/docking_port, /obj/effect/particle_effect/sparks, /obj/effect/pod_landingzone, /obj/effect/hallucination/simple/supplypod_selector,  /obj/effect/hallucination/simple/dropoff_location))
 	var/turf/oldTurf //Keeps track of where the user was at if they use the "teleport to centcom" button, so they can go back
 	var/client/holder //client of whoever is using this datum
 	var/area/centcom/supplypod/loading/bay //What bay we're using to launch shit from.

code/modules/lighting/lighting_area.dm

@@ -1,5 +1,5 @@
 /area
-	luminosity           = TRUE
+	luminosity = TRUE
 	var/dynamic_lighting = DYNAMIC_LIGHTING_ENABLED
 
 /area/proc/set_dynamic_lighting(new_dynamic_lighting = DYNAMIC_LIGHTING_ENABLED)

code/modules/lighting/lighting_atom.dm

@@ -83,11 +83,8 @@
 
 /atom/movable/Moved(atom/OldLoc, Dir)
 	. = ..()
-	var/datum/light_source/L
+	for (var/datum/light_source/light as anything in light_sources) // Cycle through the light sources on this atom and tell them to update.
-	var/thing
+		light.source_atom.update_light()
-	for (thing in light_sources) // Cycle through the light sources on this atom and tell them to update.
-		L = thing
-		L.source_atom.update_light()
 
 
 /atom/proc/flash_lighting_fx(_range = FLASH_LIGHT_RANGE, _power = FLASH_LIGHT_POWER, _color = COLOR_WHITE, _duration = FLASH_LIGHT_DURATION)

code/modules/lighting/lighting_corner.dm

@@ -2,29 +2,32 @@
 // And corners get shared between multiple turfs (unless you're on the corners of the map, then 1 corner doesn't).
 // For the record: these should never ever ever be deleted, even if the turf doesn't have dynamic lighting.
 
-
-
 /datum/lighting_corner
 	var/list/datum/light_source/affecting // Light sources affecting us.
 
-	var/x     = 0
+	var/x = 0
-	var/y     = 0
+	var/y = 0
 
 	var/turf/master_NE
 	var/turf/master_SE
 	var/turf/master_SW
 	var/turf/master_NW
 
+	//"raw" color values, changed by update_lumcount()
 	var/lum_r = 0
 	var/lum_g = 0
 	var/lum_b = 0
 
-	var/needs_update = FALSE
+	//true color values, guaranteed to be between 0 and 1
+	var/cache_r = LIGHTING_SOFT_THRESHOLD
+	var/cache_g = LIGHTING_SOFT_THRESHOLD
+	var/cache_b = LIGHTING_SOFT_THRESHOLD
 
-	var/cache_r  = LIGHTING_SOFT_THRESHOLD
+	///the maximum of lum_r, lum_g, and lum_b. if this is > 1 then the three cached color values are divided by this
-	var/cache_g  = LIGHTING_SOFT_THRESHOLD
+	var/largest_color_luminosity = 0
-	var/cache_b  = LIGHTING_SOFT_THRESHOLD
+
-	var/cache_mx = 0
+	///whether we are to be added to SSlighting's corners_queue list for an update
+	var/needs_update = FALSE
 
 /datum/lighting_corner/New(turf/new_turf, diagonal)
 	. = ..()
@@ -39,22 +42,22 @@
 	// My initial plan was to make this loop through a list of all the dirs (horizontal, vertical, diagonal).
 	// Issue being that the only way I could think of doing it was very messy, slow and honestly overengineered.
 	// So we'll have this hardcode instead.
-	var/turf/T
+	var/turf/new_master_turf
 
 	// Diagonal one is easy.
-	T = get_step(new_turf, diagonal)
+	new_master_turf = get_step(new_turf, diagonal)
-	if (T) // In case we're on the map's border.
+	if (new_master_turf) // In case we're on the map's border.
-		save_master(T, diagonal)
+		save_master(new_master_turf, diagonal)
 
 	// Now the horizontal one.
-	T = get_step(new_turf, horizontal)
+	new_master_turf = get_step(new_turf, horizontal)
-	if (T) // Ditto.
+	if (new_master_turf) // Ditto.
-		save_master(T, ((T.x > x) ? EAST : WEST) | ((T.y > y) ? NORTH : SOUTH)) // Get the dir based on coordinates.
+		save_master(new_master_turf, ((new_master_turf.x > x) ? EAST : WEST) | ((new_master_turf.y > y) ? NORTH : SOUTH)) // Get the dir based on coordinates.
 
 	// And finally the vertical one.
-	T = get_step(new_turf, vertical)
+	new_master_turf = get_step(new_turf, vertical)
-	if (T)
+	if (new_master_turf)
-		save_master(T, ((T.x > x) ? EAST : WEST) | ((T.y > y) ? NORTH : SOUTH)) // Get the dir based on coordinates.
+		save_master(new_master_turf, ((new_master_turf.x > x) ? EAST : WEST) | ((new_master_turf.y > y) ? NORTH : SOUTH)) // Get the dir based on coordinates.
 
 /datum/lighting_corner/proc/save_master(turf/master, dir)
 	switch (dir)
@@ -101,13 +104,13 @@
 	var/lum_r = src.lum_r
 	var/lum_g = src.lum_g
 	var/lum_b = src.lum_b
-	var/mx = max(lum_r, lum_g, lum_b) // Scale it so one of them is the strongest lum, if it is above 1.
+	var/largest_color_luminosity = max(lum_r, lum_g, lum_b) // Scale it so one of them is the strongest lum, if it is above 1.
 	. = 1 // factor
-	if (mx > 1)
+	if (largest_color_luminosity > 1)
-		. = 1 / mx
+		. = 1 / largest_color_luminosity
 
 	#if LIGHTING_SOFT_THRESHOLD != 0
-	else if (mx < LIGHTING_SOFT_THRESHOLD)
+	else if (largest_color_luminosity < LIGHTING_SOFT_THRESHOLD)
 		. = 0 // 0 means soft lighting.
 
 	cache_r  = round(lum_r * ., LIGHTING_ROUND_VALUE) || LIGHTING_SOFT_THRESHOLD
@@ -118,23 +121,24 @@
 	cache_g  = round(lum_g * ., LIGHTING_ROUND_VALUE)
 	cache_b  = round(lum_b * ., LIGHTING_ROUND_VALUE)
 	#endif
-	cache_mx = round(mx, LIGHTING_ROUND_VALUE)
 
-	var/atom/movable/lighting_object/lighting_object = master_NE?.lighting_object
+	src.largest_color_luminosity = round(largest_color_luminosity, LIGHTING_ROUND_VALUE)
+
+	var/datum/lighting_object/lighting_object = master_NE?.lighting_object
 	if (lighting_object && !lighting_object.needs_update)
 		lighting_object.needs_update = TRUE
 		SSlighting.objects_queue += lighting_object
-	
+
 	lighting_object = master_SE?.lighting_object
 	if (lighting_object && !lighting_object.needs_update)
 		lighting_object.needs_update = TRUE
 		SSlighting.objects_queue += lighting_object
-	
+
 	lighting_object = master_SW?.lighting_object
 	if (lighting_object && !lighting_object.needs_update)
 		lighting_object.needs_update = TRUE
 		SSlighting.objects_queue += lighting_object
-	
+
 	lighting_object = master_NW?.lighting_object
 	if (lighting_object && !lighting_object.needs_update)
 		lighting_object.needs_update = TRUE

code/modules/lighting/lighting_object.dm

@@ -1,64 +1,48 @@
-/atom/movable/lighting_object
+/datum/lighting_object
-	name          = ""
+	///the underlay we are currently applying to our turf to apply light
-
+	var/mutable_appearance/current_underlay
-	anchored      = TRUE
-
-	icon             = LIGHTING_ICON
-	icon_state       = "transparent"
-	color            = null //we manually set color in init instead
-	plane            = LIGHTING_PLANE
-	mouse_opacity = MOUSE_OPACITY_TRANSPARENT
-	invisibility     = INVISIBILITY_LIGHTING
-	vis_flags = VIS_HIDE
 
+	///whether we are already in the SSlighting.objects_queue list
 	var/needs_update = FALSE
-	var/turf/myturf
 
-/atom/movable/lighting_object/Initialize(mapload)
+	///the turf that our light is applied to
+	var/turf/affected_turf
+
+/datum/lighting_object/New(turf/source)
+	if(!isturf(source))
+		qdel(src, force=TRUE)
+		stack_trace("a lighting object was assigned to [source], a non turf! ")
+		return
 	. = ..()
-	verbs.Cut()
-	//We avoid setting this in the base as if we do then the parent atom handling will add_atom_color it and that
-	//is totally unsuitable for this object, as we are always changing it's colour manually
-	color = LIGHTING_BASE_MATRIX
 
-	myturf = loc
+	current_underlay = mutable_appearance(LIGHTING_ICON, "transparent", source.z, LIGHTING_PLANE, 255, RESET_COLOR | RESET_ALPHA | RESET_TRANSFORM)
-	if (myturf.lighting_object)
-		qdel(myturf.lighting_object, force = TRUE)
-	myturf.lighting_object = src
-	myturf.luminosity = 0
 
-	for(var/turf/open/space/S in RANGE_TURFS(1, src)) //RANGE_TURFS is in code\__HELPERS\game.dm
+	affected_turf = source
-		S.update_starlight()
+	if (affected_turf.lighting_object)
+		qdel(affected_turf.lighting_object, force = TRUE)
+		stack_trace("a lighting object was assigned to a turf that already had a lighting object!")
+
+	affected_turf.lighting_object = src
+	affected_turf.luminosity = 0
+
+	for(var/turf/open/space/space_tile in RANGE_TURFS(1, affected_turf))
+		space_tile.update_starlight()
 
 	needs_update = TRUE
 	SSlighting.objects_queue += src
 
-/atom/movable/lighting_object/Destroy(force)
+/datum/lighting_object/Destroy(force)
-	if (force)
+	if (!force)
-		SSlighting.objects_queue -= src
-		if (loc != myturf)
-			var/turf/oldturf = get_turf(myturf)
-			var/turf/newturf = get_turf(loc)
-			stack_trace("A lighting object was qdeleted with a different loc then it is suppose to have ([COORD(oldturf)] -> [COORD(newturf)])")
-		if (isturf(myturf))
-			myturf.lighting_object = null
-			myturf.luminosity = 1
-		myturf = null
-
-		return ..()
-
-	else
 		return QDEL_HINT_LETMELIVE
+	SSlighting.objects_queue -= src
+	if (isturf(affected_turf))
+		affected_turf.lighting_object = null
+		affected_turf.luminosity = 1
+		affected_turf.underlays -= current_underlay
+	affected_turf = null
+	return ..()
 
-/atom/movable/lighting_object/proc/update()
+/datum/lighting_object/proc/update()
-	if (loc != myturf)
-		if (loc)
-			var/turf/oldturf = get_turf(myturf)
-			var/turf/newturf = get_turf(loc)
-			warning("A lighting object realised it's loc had changed in update() ([myturf]\[[myturf ? myturf.type : "null"]]([COORD(oldturf)]) -> [loc]\[[ loc ? loc.type : "null"]]([COORD(newturf)]))!")
-
-		qdel(src, TRUE)
-		return
 
 	// To the future coder who sees this and thinks
 	// "Why didn't he just use a loop?"
@@ -68,31 +52,30 @@
 	// Oh it's also shorter line wise.
 	// Including with these comments.
 
-	// See LIGHTING_CORNER_DIAGONAL in lighting_corner.dm for why these values are what they are.
 	var/static/datum/lighting_corner/dummy/dummy_lighting_corner = new
 
-	var/datum/lighting_corner/cr = myturf.lighting_corner_SW || dummy_lighting_corner
+	var/datum/lighting_corner/red_corner = affected_turf.lighting_corner_SW || dummy_lighting_corner
-	var/datum/lighting_corner/cg = myturf.lighting_corner_SE || dummy_lighting_corner
+	var/datum/lighting_corner/green_corner = affected_turf.lighting_corner_SE || dummy_lighting_corner
-	var/datum/lighting_corner/cb = myturf.lighting_corner_NW || dummy_lighting_corner
+	var/datum/lighting_corner/blue_corner = affected_turf.lighting_corner_NW || dummy_lighting_corner
-	var/datum/lighting_corner/ca = myturf.lighting_corner_NE || dummy_lighting_corner
+	var/datum/lighting_corner/alpha_corner = affected_turf.lighting_corner_NE || dummy_lighting_corner
 
-	var/max = max(cr.cache_mx, cg.cache_mx, cb.cache_mx, ca.cache_mx)
+	var/max = max(red_corner.largest_color_luminosity, green_corner.largest_color_luminosity, blue_corner.largest_color_luminosity, alpha_corner.largest_color_luminosity)
 
-	var/rr = cr.cache_r
+	var/rr = red_corner.cache_r
-	var/rg = cr.cache_g
+	var/rg = red_corner.cache_g
-	var/rb = cr.cache_b
+	var/rb = red_corner.cache_b
 
-	var/gr = cg.cache_r
+	var/gr = green_corner.cache_r
-	var/gg = cg.cache_g
+	var/gg = green_corner.cache_g
-	var/gb = cg.cache_b
+	var/gb = green_corner.cache_b
 
-	var/br = cb.cache_r
+	var/br = blue_corner.cache_r
-	var/bg = cb.cache_g
+	var/bg = blue_corner.cache_g
-	var/bb = cb.cache_b
+	var/bb = blue_corner.cache_b
 
-	var/ar = ca.cache_r
+	var/ar = alpha_corner.cache_r
-	var/ag = ca.cache_g
+	var/ag = alpha_corner.cache_g
-	var/ab = ca.cache_b
+	var/ab = alpha_corner.cache_b
 
 	#if LIGHTING_SOFT_THRESHOLD != 0
 	var/set_luminosity = max > LIGHTING_SOFT_THRESHOLD
@@ -103,15 +86,20 @@
 	#endif
 
 	if((rr & gr & br & ar) && (rg + gg + bg + ag + rb + gb + bb + ab == 8))
-	//anything that passes the first case is very likely to pass the second, and addition is a little faster in this case
+		//anything that passes the first case is very likely to pass the second, and addition is a little faster in this case
-		icon_state = "transparent"
+		affected_turf.underlays -= current_underlay
-		color = null
+		current_underlay.icon_state = "transparent"
+		current_underlay.color = null
+		affected_turf.underlays += current_underlay
 	else if(!set_luminosity)
-		icon_state = "dark"
+		affected_turf.underlays -= current_underlay
-		color = null
+		current_underlay.icon_state = "dark"
+		current_underlay.color = null
+		affected_turf.underlays += current_underlay
 	else
-		icon_state = null
+		affected_turf.underlays -= current_underlay
-		color = list(
+		current_underlay.icon_state = null
+		current_underlay.color = list(
 			rr, rg, rb, 00,
 			gr, gg, gb, 00,
 			br, bg, bb, 00,
@@ -119,30 +107,6 @@
 			00, 00, 00, 01
 		)
 
-	luminosity = set_luminosity
+		affected_turf.underlays += current_underlay
 
-// Variety of overrides so the overlays don't get affected by weird things.
+	affected_turf.luminosity = set_luminosity
-
-/atom/movable/lighting_object/ex_act(severity)
-	return FALSE
-
-/atom/movable/lighting_object/singularity_act()
-	return
-
-/atom/movable/lighting_object/singularity_pull()
-	return
-
-/atom/movable/lighting_object/blob_act()
-	return
-
-/atom/movable/lighting_object/onTransitZ()
-	return
-
-/atom/movable/lighting_object/wash(clean_types)
-	SHOULD_CALL_PARENT(FALSE) // lighting objects are dirty, confirmed
-	return
-
-// Override here to prevent things accidentally moving around overlays.
-/atom/movable/lighting_object/forceMove(atom/destination, no_tp=FALSE, harderforce = FALSE)
-	if(harderforce)
-		. = ..()

code/modules/lighting/lighting_setup.dm

@@ -1,3 +1,4 @@
+
 /proc/create_all_lighting_objects()
 	for(var/area/A in world)
 		if(!IS_DYNAMIC_LIGHTING(A))
@@ -8,6 +9,6 @@
 			if(!IS_DYNAMIC_LIGHTING(T))
 				continue
 
-			new/atom/movable/lighting_object(T)
+			new/datum/lighting_object(T)
 			CHECK_TICK
 		CHECK_TICK

code/modules/lighting/lighting_source.dm

@@ -2,14 +2,21 @@
 // These are the main datums that emit light.
 
 /datum/light_source
-	var/atom/top_atom        // The atom we're emitting light from (for example a mob if we're from a flashlight that's being held).
+	///The atom we're emitting light from (for example a mob if we're from a flashlight that's being held).
-	var/atom/source_atom     // The atom that we belong to.
+	var/atom/top_atom
+	///The atom that we belong to.
+	var/atom/source_atom
 
-	var/turf/source_turf     // The turf under the above.
+	///The turf under the source atom.
-	var/turf/pixel_turf      // The turf the top_atom appears to over.
+	var/turf/source_turf
-	var/light_power    // Intensity of the emitter light.
+	///The turf the top_atom appears to over.
-	var/light_range      // The range of the emitted light.
+	var/turf/pixel_turf
-	var/light_color    // The colour of the light, string, decomposed by parse_light_color()
+	///Intensity of the emitter light.
+	var/light_power
+	/// The range of the emitted light.
+	var/light_range
+	/// The colour of the light, string, decomposed by parse_light_color()
+	var/light_color
 
 	// Variables for keeping track of the colour.
 	var/lum_r
@@ -21,11 +28,14 @@
 	var/tmp/applied_lum_g
 	var/tmp/applied_lum_b
 
-	var/list/datum/lighting_corner/effect_str     // List used to store how much we're affecting corners.
+	/// List used to store how much we're affecting corners.
+	var/list/datum/lighting_corner/effect_str
 
-	var/applied = FALSE // Whether we have applied our light yet or not.
+	/// Whether we have applied our light yet or not.
+	var/applied = FALSE
 
-	var/needs_update = LIGHTING_NO_UPDATE    // Whether we are queued for an update.
+	/// whether we are to be added to SSlighting's sources_queue list for an update
+	var/needs_update = LIGHTING_NO_UPDATE
 
 
 /datum/light_source/New(atom/owner, atom/top)
@@ -124,8 +134,7 @@
 		. * applied_lum_b                        \
 	);
 
-// This is the define used to calculate falloff.
+/// This is the define used to calculate falloff.
-
 /datum/light_source/proc/remove_lum()
 	applied = FALSE
 	for (var/datum/lighting_corner/corner as anything in effect_str)
@@ -134,14 +143,14 @@
 
 	effect_str = null
 
-/datum/light_source/proc/recalc_corner(datum/lighting_corner/C)
+/datum/light_source/proc/recalc_corner(datum/lighting_corner/corner)
 	LAZYINITLIST(effect_str)
-	if (effect_str[C]) // Already have one.
+	if (effect_str[corner]) // Already have one.
-		REMOVE_CORNER(C)
+		REMOVE_CORNER(corner)
-		effect_str[C] = 0
+		effect_str[corner] = 0
 
-	APPLY_CORNER(C)
+	APPLY_CORNER(corner)
-	effect_str[C] = .
+	effect_str[corner] = .
 
 
 /datum/light_source/proc/update_corners()
@@ -178,9 +187,9 @@
 		pixel_turf = get_turf_pixel(top_atom)
 		update = TRUE
 	else
-		var/P = get_turf_pixel(top_atom)
+		var/pixel_loc = get_turf_pixel(top_atom)
-		if (P != pixel_turf)
+		if (pixel_loc != pixel_turf)
-			pixel_turf = P
+			pixel_turf = pixel_loc
 			update = TRUE
 
 	if (!isturf(source_turf))
@@ -206,7 +215,7 @@
 		return //nothing's changed
 
 	var/list/datum/lighting_corner/corners = list()
-	var/list/turf/turfs                    = list()
+	var/list/turf/turfs = list()
 
 	if (source_turf)
 		var/oldlum = source_turf.luminosity
@@ -246,7 +255,7 @@
 				effect_str -= corner
 
 	var/list/datum/lighting_corner/gone_corners = effect_str - corners
-	for (var/datum/lighting_corner/corner as anything in gone_corners) 
+	for (var/datum/lighting_corner/corner as anything in gone_corners)
 		REMOVE_CORNER(corner)
 		LAZYREMOVE(corner.affecting, src)
 	effect_str -= gone_corners

code/modules/lighting/lighting_turf.dm

@@ -7,18 +7,18 @@
 
 /turf/proc/lighting_clear_overlay()
 	if (lighting_object)
-		qdel(lighting_object, TRUE)
+		qdel(lighting_object, force=TRUE)
 
 // Builds a lighting object for us, but only if our area is dynamic.
 /turf/proc/lighting_build_overlay()
 	if (lighting_object)
-		qdel(lighting_object,force=TRUE) //Shitty fix for lighting objects persisting after death
+		qdel(lighting_object, force=TRUE) //Shitty fix for lighting objects persisting after death
 
-	var/area/A = loc
+	var/area/our_area = loc
-	if (!IS_DYNAMIC_LIGHTING(A) && !light_sources)
+	if (!IS_DYNAMIC_LIGHTING(our_area) && !light_sources)
 		return
 
-	new/atom/movable/lighting_object(src)
+	new/datum/lighting_object(src)
 
 // Used to get a scaled lumcount.
 /turf/proc/get_lumcount(minlum = 0, maxlum = 1)
@@ -39,7 +39,7 @@
 	L = lighting_corner_NW
 	if (L)
 		totallums += L.lum_r + L.lum_b + L.lum_g
-		
+
 
 	totallums /= 12 // 4 corners, each with 3 channels, get the average.
 
@@ -57,7 +57,7 @@
 	if (!lighting_object)
 		return FALSE
 
-	return !(lighting_object.luminosity || dynamic_lumcount)
+	return !(luminosity || dynamic_lumcount)
 
 
 ///Proc to add movable sources of opacity on the turf and let it handle lighting code.
@@ -85,8 +85,7 @@
 			reconsider_lights()
 		return
 	directional_opacity = NONE
-	for(var/am in opacity_sources)
+	for(var/atom/movable/opacity_source as anything in opacity_sources)
-		var/atom/movable/opacity_source = am
 		if(opacity_source.flags_1 & ON_BORDER_1)
 			directional_opacity |= opacity_source.dir
 		else //If fulltile and opaque, then the whole tile blocks view, no need to continue checking.
@@ -107,14 +106,14 @@
 /turf/proc/generate_missing_corners()
 	if (!lighting_corner_NE)
 		lighting_corner_NE = new/datum/lighting_corner(src, NORTH|EAST)
-	
+
 	if (!lighting_corner_SE)
 		lighting_corner_SE = new/datum/lighting_corner(src, SOUTH|EAST)
-	
+
 	if (!lighting_corner_SW)
 		lighting_corner_SW = new/datum/lighting_corner(src, SOUTH|WEST)
-	
+
 	if (!lighting_corner_NW)
 		lighting_corner_NW = new/datum/lighting_corner(src, NORTH|WEST)
-	
+
 	lighting_corners_initialised = TRUE

code/modules/mob/living/simple_animal/hostile/hostile.dm

@@ -207,7 +207,7 @@
 
 // Please do not add one-off mob AIs here, but override this function for your mob
 /mob/living/simple_animal/hostile/CanAttack(atom/the_target)//Can we actually attack a possible target?
-	if(isturf(the_target) || !the_target || the_target.type == /atom/movable/lighting_object) // bail out on invalids
+	if(isturf(the_target) || !the_target) // bail out on invalids
 		return FALSE
 
 	if(ismob(the_target)) //Target is in godmode, ignore it.

code/modules/mob/living/simple_animal/hostile/mining_mobs/gutlunch.dm

@@ -51,7 +51,7 @@
 	ADD_TRAIT(src, TRAIT_VENTCRAWLER_ALWAYS, INNATE_TRAIT)
 
 /mob/living/simple_animal/hostile/asteroid/gutlunch/CanAttack(atom/the_target) // Gutlunch-specific version of CanAttack to handle stupid stat_exclusive = true crap so we don't have to do it for literally every single simple_animal/hostile except the two that spawn in lavaland
-	if(isturf(the_target) || !the_target || the_target.type == /atom/movable/lighting_object) // bail out on invalids
+	if(isturf(the_target) || !the_target) // bail out on invalids
 		return FALSE
 
 	if(see_invisible < the_target.invisibility)//Target's invisible to us, forget it

code/modules/mob/living/simple_animal/hostile/mushroom.dm

@@ -70,7 +70,7 @@
 	ADD_TRAIT(src, TRAIT_VENTCRAWLER_ALWAYS, INNATE_TRAIT)
 
 /mob/living/simple_animal/hostile/mushroom/CanAttack(atom/the_target) // Mushroom-specific version of CanAttack to handle stupid attack_same = 2 crap so we don't have to do it for literally every single simple_animal/hostile because this shit never gets spawned
-	if(!the_target || isturf(the_target) || istype(the_target, /atom/movable/lighting_object))
+	if(!the_target || isturf(the_target))
 		return FALSE
 
 	if(see_invisible < the_target.invisibility)//Target's invisible to us, forget it

code/modules/mob/mob.dm

@@ -215,7 +215,7 @@
 			msg = blind_message
 		else if(T != loc && T != src) //if src is inside something and not a turf.
 			msg = blind_message
-		else if(T.lighting_object && T.lighting_object.invisibility <= M.see_invisible && T.is_softly_lit() && !in_range(T,M)) //if it is too dark, unless we're right next to them.
+		else if(M.lighting_alpha > LIGHTING_PLANE_ALPHA_MOSTLY_INVISIBLE && T.is_softly_lit() && !in_range(T,M)) //if it is too dark, unless we're right next to them.
 			msg = blind_message
 		if(!msg)
 			continue

code/modules/recycling/conveyor2.dm

@@ -136,7 +136,7 @@ GLOBAL_LIST_EMPTY(conveyors_by_id)
 
 	//get the first 30 items in contents
 	var/turf/locturf = loc
-	var/list/items = locturf.contents - src - locturf.lighting_object
+	var/list/items = locturf.contents - src
 	if(!LAZYLEN(items))//Dont do anything at all if theres nothing there but the conveyor
 		return
 	var/list/affecting

code/modules/shuttle/on_move.dm

@@ -362,9 +362,6 @@ All ShuttleMove procs go here
 
 /************************************Misc move procs************************************/
 
-/atom/movable/lighting_object/onShuttleMove()
-	return FALSE
-
 /obj/docking_port/mobile/beforeShuttleMove(turf/newT, rotation, move_mode, obj/docking_port/mobile/moving_dock)
 	. = ..()
 	if(moving_dock == src)