Explosion Waves: Visual update and Backend rewrite

code/__DEFINES/dcs/signals/signals_subsystem.dm

@@ -3,5 +3,9 @@
 // All signals send the source datum of the signal as the first argument
 
 ///Subsystem signals
+
+/// Fired by SSexplosion_waves when reaching a synchronization checkpoint
+#define COMSIG_SS_EXPLOSION_WAVES_CHECKPOINT_REACHED "ss_explosion_waves_checkpoint_reached"
+
 ///From base of datum/controller/subsystem/Initialize
 #define COMSIG_SUBSYSTEM_POST_INITIALIZE "subsystem_post_initialize"

code/__DEFINES/subsystems.dm

@@ -165,15 +165,16 @@
 #define SS_PRIORITY_TIMER   700
 #define SS_PRIORITY_AUTOFIRE 450
 #define SS_PRIORITY_SOUND   250
+#define SS_PRIORITY_EXPLOSION_WAVES 240
 #define SS_PRIORITY_TICKER  200
 #define SS_PRIORITY_NIGHTMARE   180
 #define SS_PRIORITY_CHAT    155
 #define SS_PRIORITY_STATPANEL    154
-#define SS_PRIORITY_CELLAUTO    152
 #define SS_PRIORITY_PROJECTILES 151
 #define SS_PRIORITY_MOB 150
 #define SS_PRIORITY_XENO    149
 #define SS_PRIORITY_HUMAN   148
+#define SS_PRIORITY_DELAYED_EX_ACT 140
 #define SS_PRIORITY_STAMINA 126
 #define SS_PRIORITY_COMPONENT   125
 #define SS_PRIORITY_NANOUI  120

code/__DEFINES/turf_flags.dm

@@ -11,6 +11,8 @@
 #define TURF_BURNT (1<<6)
 #define TURF_BREAKABLE (1<<7)
 #define TURF_BROKEN (1<<8)
+/// Turf is primarily comprised of water, such as a river or ocean turf
+#define TURF_IS_WATER (1<<9)
 
 //ChangeTurf options to change its behavior
 #define CHANGETURF_DEFER_CHANGE (1<<0)

code/controllers/subsystem/delayed_ex_act.dm

@@ -0,0 +1,32 @@
+/// Handles ex_act calls to expensive things like mobs as defered actions to preserve game under high load
+SUBSYSTEM_DEF(delayed_ex_act)
+	name       = "Delayed Explosion Effects"
+	priority   = SS_PRIORITY_DELAYED_EX_ACT // High prio but not SS_TICKER and shouldn't be used much
+	wait       = 0.5 DECISECONDS
+	flags      = SS_NO_INIT
+	runlevels  = RUNLEVELS_DEFAULT | RUNLEVEL_LOBBY
+
+	var/list/list/queued_work = list()
+	var/list/list/current_work
+
+/datum/controller/subsystem/delayed_ex_act/fire(resumed = FALSE)
+	if(!resumed)
+		current_work = queued_work.Copy()
+		queued_work = list()
+
+	while(length(current_work))
+		var/list/order = current_work[current_work.len]
+		current_work.len--
+		var/atom/target = order[1]
+		if(!QDELETED(target)) // Very neccessary here
+			var/list/arguments = order.Copy(2, 0)
+			if(isliving(target) && length(arguments) >= 3)
+				var/datum/cause_data/cause_data = arguments[3]
+				log_explosion(target, cause_data)
+			target.ex_act(arglist(arguments))
+
+		if(MC_TICK_CHECK)
+			return
+
+/datum/controller/subsystem/delayed_ex_act/proc/queue(atom/target, power, dir, datum/cause_data/cause_data, pierce = FALSE, enviro = FALSE)
+	queued_work += list(list(target, power, dir, cause_data, pierce, enviro))

code/controllers/subsystem/explosion_waves.dm

@@ -0,0 +1,55 @@
+SUBSYSTEM_DEF(explosion_waves)
+	name     = "Explosion Waves"
+	wait     = 1
+	flags    = SS_TICKER | SS_NO_INIT
+	priority = SS_PRIORITY_EXPLOSION_WAVES
+
+	var/list/datum/explosion_wave/queued = list()
+	var/list/datum/explosion_wave/currentrun
+
+	/// List of synchronization checkpoints. An arbitrary tag, followed by the explosion_wave-s that existed at that time
+	/// When all of these waves are gone, we fire a signal to let listeners know we've progressed past that state
+	var/alist/checkpoints = alist()
+
+/datum/controller/subsystem/explosion_waves/fire(resumed = FALSE)
+	if(!resumed)
+		currentrun = queued.Copy()
+
+	while(length(currentrun))
+		var/datum/explosion_wave/current = currentrun[currentrun.len]
+		currentrun.len--
+		var/ret = current?.process(wait * world.tick_lag)
+		if(ret == PROCESS_KILL)
+			queued -= current
+		if(MC_TICK_CHECK)
+			return
+
+	for(var/name, checkpoint in checkpoints)
+		if(!length(checkpoint & queued))
+			checkpoints -= name
+			SEND_GLOBAL_SIGNAL(COMSIG_SS_EXPLOSION_WAVES_CHECKPOINT_REACHED, name)
+
+/datum/controller/subsystem/explosion_waves/proc/queue(datum/explosion_wave/item)
+	queued += item
+
+/datum/controller/subsystem/explosion_waves/proc/forget(datum/explosion_wave/item)
+	queued -= item
+	currentrun -= item
+
+	for(var/name, contents in checkpoints)
+		var/list/datum/explosion_wave/checkpoint_waves = contents
+		checkpoint_waves -= item
+
+/datum/controller/subsystem/explosion_waves/proc/set_checkpoint(name)
+	checkpoints[name] = queued.Copy()
+
+/// Waits until reaching said checkpoint. DON'T USE THIS PLEASE USE THE SIGNALS ABOVE
+/datum/controller/subsystem/explosion_waves/proc/synchronize(name)
+	if(isnull(name))
+		var/static/notch = 1
+		name = "_dynamic_checkpoint_[notch++]"
+		set_checkpoint(name)
+	else if(!(name in checkpoints))
+		return TRUE
+	UNTIL(!(name in checkpoints))
+	return TRUE

code/controllers/subsystem/ticker.dm

@@ -496,7 +496,6 @@ SUBSYSTEM_DEF(ticker)
 	 * SSsound: lowering SSsound freq probably won't help because it's just a worker for the sound queue, same amount of work gets queued anyway
 	 * SSmob/SShuman/SSxeno: you don't want to touch these, because several systems down the line rely on the timing (2 SECONDS) for gameplay logic
 	 * SSchat/SSinput: these are perf intensive but need to be SS_TICKER, changing wait would be troublesome and/or inconsequential for perf
-	 * SScellauto: can't touch this because it would directly affect explosion spread speed
 	 */
 
 	SSlighting?.wait    = 0.6 SECONDS // From 0.4, same but also heavily scales on player/scene density (higher = less frequent lighting updates which is very noticeable as you move)

code/datums/ammo/shrapnel.dm

@@ -149,11 +149,11 @@
 	icon_state = "shrapnel_glass"
 
 /particles/shrapnel
-	icon = 'icons/obj/items/weapons/projectiles.dmi'
-	icon_state = "shrapnel_bright2"
+	icon = 'icons/effects/particles/generic_particles.dmi'
+	icon_state = "spark"
 	width = 1000
 	height = 1000
-	count = 100
+	count = 200
 	spawning = 0
 	lifespan = 0.6 SECONDS
 	fadein = 0.2 SECONDS
@@ -169,7 +169,7 @@
 /obj/shrapnel_effect/New()
 	. = ..()
 	particles = new /particles/shrapnel
-	particles.spawning = rand(5,9) + rand(5,9)
+	particles.spawning = rand(50,80)
 	addtimer(CALLBACK(src, PROC_REF(stop)), 0.1 SECONDS)
 	QDEL_IN(src, 0.9 SECONDS)