Flying mobs now clip past non flying mobs, various flightsuit/iontrail/movement tweaks/code improvements/bugfixes

code/game/objects/effects/effect_system/effects_other.dm

@@ -8,8 +8,13 @@
 
 /datum/effect_system/trail_follow
 	var/turf/oldposition
-	var/processing = TRUE
-	var/on = TRUE
+	var/active = FALSE
+	var/allow_overlap = FALSE
+	var/auto_process = TRUE
+	var/qdel_in_time = 10
+	var/fadetype = "ion_fade"
+	var/fade = TRUE
+	var/nograv_required = FALSE
 
 /datum/effect_system/trail_follow/set_up(atom/atom)
 	attach(atom)
@@ -17,37 +22,49 @@
 
 /datum/effect_system/trail_follow/Destroy()
 	oldposition = null
+	stop()
 	return ..()
 
 /datum/effect_system/trail_follow/proc/stop()
-	processing = FALSE
-	on = FALSE
 	oldposition = null
+	STOP_PROCESSING(SSfastprocess, src)
+	active = FALSE
+	return TRUE
+
+/datum/effect_system/trail_follow/start()
+	oldposition = get_turf(holder)
+	if(!check_conditions())
+		return FALSE
+	if(auto_process)
+		START_PROCESSING(SSfastprocess, src)
+	active = TRUE
+	return TRUE
+
+/datum/effect_system/trail_follow/process()
+	generate_effect()
+
+/datum/effect_system/trail_follow/generate_effect()
+	if(!check_conditions())
+		return stop()
+	if(oldposition && !(oldposition == get_turf(holder)))
+		if(!oldposition.has_gravity() || !nograv_required)
+			var/obj/effect/E = new effect_type(oldposition)
+			set_dir(E)
+			if(fade)
+				flick(fadetype, E)
+				E.icon_state = ""
+			if(qdel_in_time)
+				QDEL_IN(E, qdel_in_time)
+	oldposition = get_turf(holder)
+
+/datum/effect_system/trail_follow/proc/check_conditions()
+	if(!get_turf(holder))
+		return FALSE
+	return TRUE
 
 /datum/effect_system/trail_follow/steam
 	effect_type = /obj/effect/particle_effect/steam
 
-/datum/effect_system/trail_follow/steam/start()
-	if(!on)
-		on = TRUE
-		processing = TRUE
-		if(!oldposition)
-			oldposition = get_turf(holder)
-	if(processing)
-		processing = FALSE
-		if(number < 3)
-			var/obj/effect/particle_effect/steam/I = new /obj/effect/particle_effect/steam(oldposition)
-			number++
-			I.setDir(holder.dir)
-			oldposition = get_turf(holder)
-			spawn(10)
-				qdel(I)
-				number--
-		spawn(2)
-			if(on)
-				processing = TRUE
-				start()
-
 /obj/effect/particle_effect/ion_trails
 	name = "ion trails"
 	icon_state = "ion_trails"
@@ -58,47 +75,23 @@
 
 /datum/effect_system/trail_follow/ion
 	effect_type = /obj/effect/particle_effect/ion_trails
-	var/fadetype = "ion_fade"
-	var/fade = 1
-	var/nograv_required = 1
+	nograv_required = TRUE
+	qdel_in_time = 20
 
-/datum/effect_system/trail_follow/ion/start() //Whoever is responsible for this abomination of code should become an hero
-	if(!on)
-		on = TRUE
-		processing = TRUE
-		if(!oldposition)
-			oldposition = get_turf(holder)
-	if(processing)
-		processing = FALSE
-		var/turf/T = get_turf(holder)
-		if(T != oldposition)
-			if(!T.has_gravity() || !nograv_required)
-				var/obj/effect/particle_effect/ion_trails/I = new effect_type(oldposition)
-				set_dir(I)
-				if(fade)
-					flick(fadetype, I)
-					I.icon_state = ""
-				spawn(20)
-					qdel(I)
-			oldposition = T
-		spawn(2)
-			if(on)
-				processing = TRUE
-				start()
-
-/datum/effect_system/trail_follow/ion/proc/set_dir(obj/effect/particle_effect/ion_trails/I)
+/datum/effect_system/trail_follow/proc/set_dir(obj/effect/particle_effect/ion_trails/I)
 	I.setDir(holder.dir)
 
 /datum/effect_system/trail_follow/ion/flight
 	effect_type = /obj/effect/particle_effect/ion_trails/flight
 	fadetype = "ion_fade_flight"
-	nograv_required = 0
+	nograv_required = FALSE
+	auto_process = FALSE
 
 /datum/effect_system/trail_follow/ion/flight/set_dir(obj/effect/particle_effect/ion_trails/I)
 	if(istype(holder, /obj/item/device/flightpack))
 		var/obj/item/device/flightpack/F = holder
-		I.setDir(F.suit.user.dir)
-
+		if(istype(F.wearer))
+			I.setDir(F.wearer.dir)
 
 //Reagent-based explosion effect
 

code/game/objects/objs.dm

@@ -189,7 +189,7 @@
 /obj/proc/check_uplink_validity()
 	return 1
 
-/obj/proc/on_mob_move(dir, mob, oldLoc)
+/obj/proc/on_mob_move(dir, mob, oldLoc, forced)
 	return
 
 /obj/proc/on_mob_turn(dir, mob)