Optimization pass focused on foam code (saves about 30% of cpu usage I think)

code/__DEFINES/subsystems.dm

@@ -197,9 +197,9 @@
 #define FIRE_PRIORITY_GARBAGE 15
 #define FIRE_PRIORITY_DATABASE 16
 #define FIRE_PRIORITY_WET_FLOORS 20
-#define FIRE_PRIORITY_FLUIDS 20
 #define FIRE_PRIORITY_AIR 20
 #define FIRE_PRIORITY_NPC 20
+#define FIRE_PRIORITY_ASSETS 20
 #define FIRE_PRIORITY_HYPERSPACE_DRIFT 20
 #define FIRE_PRIORITY_NPC_MOVEMENT 21
 #define FIRE_PRIORITY_NPC_ACTIONS 22
@@ -215,8 +215,8 @@
 #define FIRE_PRIORITY_DEFAULT 50
 #define FIRE_PRIORITY_PARALLAX 65
 #define FIRE_PRIORITY_INSTRUMENTS 80
+#define FIRE_PRIORITY_FLUIDS 80
 #define FIRE_PRIORITY_MOBS 100
-#define FIRE_PRIORITY_ASSETS 105
 #define FIRE_PRIORITY_TGUI 110
 #define FIRE_PRIORITY_TICKER 200
 #define FIRE_PRIORITY_STATPANEL 390

code/__HELPERS/reagents.dm

@@ -73,10 +73,10 @@
 /proc/add_chemical_reaction(datum/chemical_reaction/R)
 	if(!GLOB.chemical_reactions_list_reactant_index || !R.required_reagents || !R.required_reagents.len)
 		return
-	var/primary_reagent = R.required_reagents[1]
-	if(!GLOB.chemical_reactions_list_reactant_index[primary_reagent])
-		GLOB.chemical_reactions_list_reactant_index[primary_reagent] = list()
-	GLOB.chemical_reactions_list_reactant_index[primary_reagent] += R
+	var/rand_reagent = pick(R.required_reagents)
+	if(!GLOB.chemical_reactions_list_reactant_index[rand_reagent])
+		GLOB.chemical_reactions_list_reactant_index[rand_reagent] = list()
+	GLOB.chemical_reactions_list_reactant_index[rand_reagent] += R
 
 //Creates foam from the reagent. Metaltype is for metal foam, notification is what to show people in textbox
 /datum/reagents/proc/create_foam(foamtype, foam_volume, result_type = null, notification = null, log = FALSE)

code/controllers/subsystem/fluids.dm

@@ -20,8 +20,9 @@
 SUBSYSTEM_DEF(fluids)
 	name = "Fluid"
 	wait = 0 // Will be autoset to whatever makes the most sense given the spread and effect waits.
-	flags = SS_BACKGROUND|SS_KEEP_TIMING
+	flags = SS_KEEP_TIMING
 	runlevels = RUNLEVEL_GAME|RUNLEVEL_POSTGAME
+	priority = FIRE_PRIORITY_FLUIDS
 
 	// Fluid spread processing:
 	/// The amount of time (in deciseconds) before a fluid node is created and when it spreads.
@@ -34,8 +35,6 @@ SUBSYSTEM_DEF(fluids)
 	var/spread_bucket_index
 	/// The set of fluid nodes we are currently processing spreading for.
 	var/list/currently_spreading
-	/// Whether the subsystem has resumed spreading fluid.
-	var/resumed_spreading
 
 	// Fluid effect processing:
 	/// The amount of time (in deciseconds) between effect processing ticks for each fluid node.
@@ -48,8 +47,6 @@ SUBSYSTEM_DEF(fluids)
 	var/effect_bucket_index
 	/// The set of fluid nodes we are currently processing effects for.
 	var/list/currently_processing
-	/// Whether the subsystem has resumed processing fluid effects.
-	var/resumed_effect_processing
 
 /datum/controller/subsystem/fluids/Initialize()
 	initialize_waits()
@@ -121,14 +118,15 @@ SUBSYSTEM_DEF(fluids)
 	var/seconds_per_tick
 	var/cached_bucket_index
 	var/list/obj/effect/particle_effect/fluid/currentrun
+	// Ok so like I get the lighting style splittick but why are we doing this churn thing
+	// It seems like a bad idea for processing to get out of step with spreading
 	MC_SPLIT_TICK_INIT(2)
 
-	MC_SPLIT_TICK // Start processing fluid spread:
-	if(!resumed_spreading)
+	MC_SPLIT_TICK // Start processing fluid spread (we take a lot of cpu for ourselves, spreading is more important after all)
+	if(!resumed)
 		spread_bucket_index = WRAP_UP(spread_bucket_index, num_spread_buckets)
 		currently_spreading = spread_carousel[spread_bucket_index]
 		spread_carousel[spread_bucket_index] = list() // Reset the bucket so we don't process an _entire station's worth of foam_ spreading every 2 ticks when the foam flood event happens.
-		resumed_spreading = TRUE
 
 	seconds_per_tick = spread_wait / (1 SECONDS)
 	currentrun = currently_spreading
@@ -143,15 +141,11 @@ SUBSYSTEM_DEF(fluids)
 		if (MC_TICK_CHECK)
 			break
 
-	if(!currentrun.len)
-		resumed_spreading = FALSE
-
 	MC_SPLIT_TICK // Start processing fluid effects:
-	if(!resumed_effect_processing)
+	if(!resumed)
 		effect_bucket_index = WRAP_UP(effect_bucket_index, num_effect_buckets)
 		var/list/tmp_list = effect_carousel[effect_bucket_index]
 		currently_processing = tmp_list.Copy()
-		resumed_effect_processing = TRUE
 
 	seconds_per_tick = effect_wait / (1 SECONDS)
 	cached_bucket_index = effect_bucket_index
@@ -168,10 +162,6 @@ SUBSYSTEM_DEF(fluids)
 		if (MC_TICK_CHECK)
 			break
 
-	if(!currentrun.len)
-		resumed_effect_processing = FALSE
-
-
 /**
  * Queues a fluid node to spread later after one full carousel rotation.
  *

code/datums/elements/atmos_sensitive.dm

@@ -4,35 +4,38 @@
 //Don't put it on things that tend to clump into one spot, you will cause lag spikes.
 /datum/element/atmos_sensitive
 	element_flags = ELEMENT_DETACH_ON_HOST_DESTROY
-	var/static/list/pass_on = list(COMSIG_TURF_EXPOSE = /atom/proc/check_atmos_process)
 
 /datum/element/atmos_sensitive/Attach(datum/target, mapload)
 	if(!isatom(target)) //How
 		return ELEMENT_INCOMPATIBLE
 	var/atom/to_track = target
-	to_track.AddElement(/datum/element/connect_loc, pass_on)
+	if(to_track.loc)
+		to_track.RegisterSignal(to_track.loc, COMSIG_TURF_EXPOSE, TYPE_PROC_REF(/atom, check_atmos_process))
 	RegisterSignal(to_track, COMSIG_MOVABLE_MOVED, PROC_REF(react_to_move))
 
 	if(!mapload && isopenturf(to_track.loc))
 		to_track.atmos_conditions_changed() //Make sure you're properly registered
 
 	return ..()
 
-/datum/element/atmos_sensitive/Detach(datum/source)
-	var/atom/us = source
-	us.RemoveElement(/datum/element/connect_loc, pass_on)
+/datum/element/atmos_sensitive/Detach(atom/source)
+	if(source.loc)
+		UnregisterSignal(source.loc, COMSIG_TURF_EXPOSE)
 	UnregisterSignal(source, COMSIG_MOVABLE_MOVED)
-	if(us.flags_1 & ATMOS_IS_PROCESSING_1)
-		us.atmos_end()
-		SSair.atom_process -= us
-		us.flags_1 &= ~ATMOS_IS_PROCESSING_1
+	if(source.flags_1 & ATMOS_IS_PROCESSING_1)
+		source.atmos_end()
+		SSair.atom_process -= source
+		source.flags_1 &= ~ATMOS_IS_PROCESSING_1
 	return ..()
 
-/datum/element/atmos_sensitive/proc/react_to_move(datum/source, atom/movable/oldloc, direction, forced)
+/datum/element/atmos_sensitive/proc/react_to_move(atom/source, atom/movable/oldloc, direction, forced)
 	SIGNAL_HANDLER
 
-	var/atom/atom_source = source
-	atom_source.atmos_conditions_changed() //Make sure you're properly registered
+	if(oldloc)
+		source.UnregisterSignal(oldloc, COMSIG_TURF_EXPOSE)
+	if(source.loc)
+		source.RegisterSignal(source.loc, COMSIG_TURF_EXPOSE, TYPE_PROC_REF(/atom, check_atmos_process))
+	source.atmos_conditions_changed() //Make sure you're properly registered
 
 /atom/proc/check_atmos_process(datum/source, datum/gas_mixture/air, exposed_temperature)
 	SIGNAL_HANDLER

code/datums/elements/forced_gravity.dm

@@ -11,14 +11,18 @@
 	if(!isatom(target))
 		return ELEMENT_INCOMPATIBLE
 
+	var/our_ref = REF(src)
+	if(HAS_TRAIT_FROM(target, TRAIT_FORCED_GRAVITY, our_ref))
+		return
+
 	src.gravity = gravity
 	src.ignore_turf_gravity = ignore_turf_gravity
 
 	RegisterSignal(target, COMSIG_ATOM_HAS_GRAVITY, PROC_REF(gravity_check))
 	if(isturf(target))
 		RegisterSignal(target, COMSIG_TURF_HAS_GRAVITY, PROC_REF(turf_gravity_check))
 
-	ADD_TRAIT(target, TRAIT_FORCED_GRAVITY, REF(src))
+	ADD_TRAIT(target, TRAIT_FORCED_GRAVITY, our_ref)
 
 /datum/element/forced_gravity/Detach(datum/source)
 	. = ..()
@@ -37,5 +41,4 @@
 
 /datum/element/forced_gravity/proc/turf_gravity_check(datum/source, atom/checker, list/gravs)
 	SIGNAL_HANDLER
-
-	return gravity_check(null, source, gravs)
+	gravity_check(null, source, gravs)

code/decal.dm

@@ -0,0 +1,8 @@
+// Bitflags that describes what turfs a decal is NOT ok with sittin on
+
+/// Blocks closed turfs
+#define DECAL_BLOCK_CLOSED_TURF (1<<0)
+/// Blocks groundless turfs
+#define DECAL_BLOCK_GROUNDLESS_TURF (1<<1)
+/// Allows groundless turfs IF the turf below exists
+#define DECAL_GROUNDLESS_ALLOW_FLOOR_BELOW_TURF (1<<2)

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

@@ -16,6 +16,18 @@
 	///The amount of reagent this decal holds, if decal_reagent is defined
 	var/reagent_amount = 0
 
+/// Creates a cleanable decal on a turf
+/// Use this if your decal is one of one, and thus we should not spawn it if it's there already
+/// Returns either the existing cleanable, the one we created, or null if we can't spawn on that turf
+/turf/proc/spawn_unique_cleanable(obj/effect/decal/cleanable/cleanable_type)
+	// There is no need to spam unique cleanables, they don't stack and it just chews cpu
+	var/obj/effect/decal/cleanable/existing = locate(cleanable_type) in src
+	if(existing)
+		return existing
+	if(decal_turf_compatability(src, initial(cleanable_type.turf_loc_flags)))
+		return null
+	return new cleanable_type(src)
+
 /obj/effect/decal/cleanable/Initialize(mapload, list/datum/disease/diseases)
 	. = ..()
 	if (random_icon_states && (icon_state == initial(icon_state)) && length(random_icon_states) > 0)

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

@@ -73,7 +73,7 @@
 	layer = ABOVE_WINDOW_LAYER
 	plane = GAME_PLANE
 	vis_flags = VIS_INHERIT_PLANE
-	turf_loc_check = FALSE
+	turf_loc_flags = NONE
 	alpha = 180
 
 /obj/effect/decal/cleanable/blood/tracks
@@ -103,7 +103,7 @@
 	plane = GAME_PLANE
 	random_icon_states = list("gib1", "gib2", "gib3", "gib4", "gib5", "gib6")
 	mergeable_decal = FALSE
-	turf_loc_check = FALSE
+	turf_loc_flags = NONE
 
 	dryname = "rotting gibs"
 	drydesc = "They look bloody and gruesome while some terrible smell fills the air."

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

@@ -20,9 +20,9 @@
 	pixel_x = base_pixel_x + rand(-5, 5)
 	pixel_y = base_pixel_y + rand(-5, 5)
 
-/obj/effect/decal/cleanable/ash/crematorium
 //crematoriums need their own ash cause default ash deletes itself if created in an obj
-	turf_loc_check = FALSE
+/obj/effect/decal/cleanable/ash/crematorium
+	turf_loc_flags = NONE
 
 /obj/effect/decal/cleanable/ash/large
 	name = "large pile of ashes"

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

@@ -7,6 +7,7 @@
 	plane = GAME_PLANE //makes the graffiti visible over a wall.
 	mergeable_decal = FALSE
 	flags_1 = ALLOW_DARK_PAINTS_1
+	turf_loc_flags = DECAL_BLOCK_GROUNDLESS_TURF
 	var/do_icon_rotate = TRUE
 	var/rotation = 0
 	var/paint_colour = "#FFFFFF"
@@ -31,9 +32,6 @@
 	add_atom_colour(paint_colour, FIXED_COLOUR_PRIORITY)
 	RegisterSignal(src, COMSIG_OBJ_PAINTED, PROC_REF(on_painted))
 
-/obj/effect/decal/cleanable/crayon/NeverShouldHaveComeHere(turf/T)
-	return isgroundlessturf(T)
-
 /obj/effect/decal/cleanable/crayon/proc/on_painted(datum/source, mob/user, obj/item/toy/crayon/spraycan/spraycan, is_dark_color)
 	SIGNAL_HANDLER
 	var/cost = spraycan.all_drawables[icon_state] || CRAYON_COST_DEFAULT

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

@@ -3,14 +3,14 @@
 	plane = FLOOR_PLANE
 	anchored = TRUE
 	resistance_flags = FIRE_PROOF | UNACIDABLE | ACID_PROOF
-	///Boolean on whether this decal can be placed inside of groundless turfs/walls. If FALSE, will runtime and delete if it happens.
-	var/turf_loc_check = TRUE
+	/// Bitfield that describes what turfs this decal is ok with spawning on. Read only, as we read it using initial() in some places
+	var/turf_loc_flags = DECAL_BLOCK_CLOSED_TURF|DECAL_BLOCK_GROUNDLESS_TURF|DECAL_GROUNDLESS_ALLOW_FLOOR_BELOW_TURF
 
 /obj/effect/decal/Initialize(mapload)
 	. = ..()
-	if(turf_loc_check && NeverShouldHaveComeHere(loc))
+	if(turf_loc_flags && decal_turf_compatability(loc, turf_loc_flags))
 #ifdef UNIT_TESTS
-		stack_trace("[name] spawned in a bad turf ([loc]) at [AREACOORD(src)] in \the [get_area(src)]. Please remove it or set turf_loc_check to FALSE on the decal if intended.")
+		stack_trace("[name] spawned in a bad turf ([loc]) at [AREACOORD(src)] in \the [get_area(src)]. Please remove it or set turf_loc_flags to NONE on the decal if intended.")
 #else
 		return INITIALIZE_HINT_QDEL
 #endif
@@ -23,9 +23,6 @@
 	if(B && B.loc == loc)
 		qdel(src)
 
-/obj/effect/decal/proc/NeverShouldHaveComeHere(turf/T)
-	return isclosedturf(T) || (isgroundlessturf(T) && !SSmapping.get_turf_below(T))
-
 /obj/effect/decal/ex_act(severity, target)
 	qdel(src)
 	return TRUE
@@ -39,9 +36,17 @@
 	post_change_callbacks += CALLBACK(src, PROC_REF(sanity_check_self))
 
 /obj/effect/decal/proc/sanity_check_self(turf/changed)
-	if(changed == loc && NeverShouldHaveComeHere(changed))
+	if(changed == loc && decal_turf_compatability(changed, turf_loc_flags))
 		qdel(src)
 
+/proc/decal_turf_compatability(turf/check, flags)
+	if(flags & DECAL_BLOCK_CLOSED_TURF && isclosedturf(check))
+		return TRUE
+	if(flags & DECAL_BLOCK_GROUNDLESS_TURF && isgroundlessturf(check))
+		if(!(flags & DECAL_GROUNDLESS_ALLOW_FLOOR_BELOW_TURF) || !SSmapping.get_turf_below(check))
+			return TRUE
+	return FALSE
+
 //////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
 
 /obj/effect/turf_decal

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

@@ -48,7 +48,7 @@
 
 /obj/effect/decal/remains/plasma
 	icon_state = "remainsplasma"
-	turf_loc_check = FALSE
+	turf_loc_flags = NONE
 
 /obj/effect/decal/remains/xeno
 	desc = "They look like the remains of something... alien. They have a strange aura about them."

code/game/objects/effects/effect_system/fluid_spread/effects_foam.dm

@@ -137,7 +137,11 @@
 	if(!istype(location))
 		return FALSE
 
-	for(var/turf/spread_turf as anything in location.reachableAdjacentTurfs(no_id = TRUE))
+	for(var/iter_dir in GLOB.cardinals)
+		var/turf/spread_turf = get_step(src, iter_dir)
+		if(spread_turf?.density || spread_turf.LinkBlockedWithAccess(spread_turf, no_id = TRUE))
+			continue
+
 		var/obj/effect/particle_effect/fluid/foam/foundfoam = locate() in spread_turf //Don't spread foam where there's already foam!
 		if(foundfoam)
 			continue

code/modules/mapfluff/ruins/lavalandruin_code/elephantgraveyard.dm

@@ -276,7 +276,8 @@
 	new /obj/item/book/granter/crafting_recipe/boneyard_notes(src)
 
 /obj/effect/decal/remains/human/grave
-	turf_loc_check = FALSE
+	turf_loc_flags = NONE
+
 
 //***Fluff items for lore/intrigue
 /obj/item/paper/crumpled/muddy/fluff/elephant_graveyard