Fixes cleanable floor decals shading jank (#19227)

* Yep

* Sirryan2002 Suggestion

Co-authored-by: Sirryan2002 <80364400+Sirryan2002@users.noreply.github.com>

Co-authored-by: Sirryan2002 <80364400+Sirryan2002@users.noreply.github.com>

code/game/objects/effects/decals/Cleanable/humans.dm

@@ -10,7 +10,6 @@ GLOBAL_LIST_EMPTY(splatter_cache)
 	gender = PLURAL
 	density = FALSE
 	layer = TURF_LAYER
-	plane = GAME_PLANE
 	icon = 'icons/effects/blood.dmi'
 	icon_state = "mfloor1"
 	random_icon_states = list("mfloor1", "mfloor2", "mfloor3", "mfloor4", "mfloor5", "mfloor6", "mfloor7")

code/game/objects/effects/decals/Cleanable/misc.dm

@@ -15,12 +15,14 @@
 	icon_state = "ash"
 	scoop_reagents = list("ash" = 10)
 	mergeable_decal = FALSE
+	plane = GAME_PLANE
 
 /obj/effect/decal/cleanable/glass
 	name = "tiny shards"
 	desc = "Back to sand."
 	icon = 'icons/obj/shards.dmi'
 	icon_state = "tiny"
+	plane = GAME_PLANE
 
 /obj/effect/decal/cleanable/glass/Initialize(mapload)
 	. = ..()
@@ -104,6 +106,7 @@
 	desc = "Somebody should remove that."
 	density = FALSE
 	layer = OBJ_LAYER
+	plane = GAME_PLANE
 	icon = 'icons/effects/effects.dmi'
 	icon_state = "cobweb1"
 	resistance_flags = FLAMMABLE
@@ -113,6 +116,7 @@
 	desc = "It looks like a melted... something."
 	density = FALSE
 	layer = OBJ_LAYER
+	plane = GAME_PLANE
 	gender = NEUTER
 	icon = 'icons/effects/effects.dmi'
 	icon_state = "molten"
@@ -127,6 +131,7 @@
 	desc = "Somebody should remove that."
 	density = FALSE
 	layer = OBJ_LAYER
+	plane = GAME_PLANE
 	icon = 'icons/effects/effects.dmi'
 	icon_state = "cobweb2"
 
@@ -154,6 +159,7 @@
 	desc = "The shredded remains of what appears to be clothing."
 	icon_state = "shreds"
 	gender = PLURAL
+	plane = GAME_PLANE
 	mergeable_decal = FALSE
 
 /obj/effect/decal/cleanable/shreds/ex_act(severity, target)
@@ -212,6 +218,7 @@
 	name = "confetti"
 	desc = "Party time!"
 	gender = PLURAL
+	plane = GAME_PLANE
 	icon = 'icons/obj/objects.dmi'
 	icon_state = "confetti1"
 	random_icon_states = list("confetti1", "confetti2", "confetti3")

code/game/objects/effects/decals/cleanable.dm

@@ -2,6 +2,7 @@
 	var/list/random_icon_states = list()
 	var/bloodiness = 0 //0-100, amount of blood in this decal, used for making footprints and affecting the alpha of bloody footprints
 	var/mergeable_decal = TRUE //when two of these are on a same tile or do we need to merge them into just one?
+	plane = FLOOR_PLANE //prevents Ambient Occlusion effects around it ; Set to GAME_PLANE in Initialize() if on a wall
 
 /obj/effect/decal/cleanable/proc/replace_decal(obj/effect/decal/cleanable/C) // Returns true if we should give up in favor of the pre-existing decal
 	if(mergeable_decal)
@@ -81,6 +82,8 @@
 	if(smoothing_flags)
 		QUEUE_SMOOTH(src)
 		QUEUE_SMOOTH_NEIGHBORS(src)
+	if(iswallturf(loc) && plane == FLOOR_PLANE)
+		plane = GAME_PLANE // so they can be seen above walls
 
 /obj/effect/decal/cleanable/Destroy()
 	if(smoothing_flags)

code/game/objects/effects/decals/crayon.dm

@@ -4,7 +4,6 @@
 	icon = 'icons/effects/crayondecal.dmi'
 	icon_state = "rune1"
 	layer = MID_TURF_LAYER
-	plane = GAME_PLANE //makes the graffiti visible over a wall.
 	mergeable_decal = FALSE // Allows crayon drawings to overlap one another.