Projectile refactoring madness (#19878)

Refactored the projectile code, mostly in line with TG's now.
Refactored various procs that are used or depends on it.
Projectiles can now ricochet if enabled to.
Damage falloffs with distance.
Homing projectiles can now have accuracy falloff with distance.
Projectiles have a maximum range.
Muzzle flash is configurable per projectile.
Impact effect of the projectile is configurable per projectile.
Accuracy decreases with distance.
Projectiles work with signals and emits them, for easy hooking up from
other parts of the code.
Meatshielding is now less effective .
Impact sound is now configurable per projectile.

High risk.

code/modules/shieldgen/emergency_shield.dm

@@ -56,8 +56,13 @@
 	return ..()
 
 /obj/machinery/shield/CanPass(atom/movable/mover, turf/target, height, air_group)
-	if(!height || air_group) return FALSE
-	else return ..()
+	if(mover?.movement_type & PHASING)
+		return TRUE
+
+	if(!height || air_group)
+		return FALSE
+	else
+		return ..()
 
 /obj/machinery/shield/attackby(obj/item/attacking_item, mob/user)
 	user.setClickCooldown(DEFAULT_ATTACK_COOLDOWN)
@@ -74,9 +79,12 @@
 
 	..()
 
-/obj/machinery/shield/bullet_act(var/obj/projectile/Proj)
-	health -= Proj.get_structure_damage()
-	..()
+/obj/machinery/shield/bullet_act(obj/projectile/hitting_projectile, def_zone, piercing_hit)
+	. = ..()
+	if(. != BULLET_ACT_HIT)
+		return .
+
+	health -= hitting_projectile.get_structure_damage()
 	check_failure()
 	opacity = 1
 	spawn(20) if(src) opacity = FALSE

code/modules/shieldgen/energy_field.dm

@@ -54,8 +54,12 @@
 /obj/effect/energy_field/ex_act(var/severity)
 	Stress(0.5 + severity)
 
-/obj/effect/energy_field/bullet_act(var/obj/projectile/Proj)
-	Stress(Proj.get_structure_damage() / 10)
+/obj/effect/energy_field/bullet_act(obj/projectile/hitting_projectile, def_zone, piercing_hit)
+	. = ..()
+	if(. != BULLET_ACT_HIT)
+		return .
+
+	Stress(hitting_projectile.get_structure_damage() / 10)
 
 /obj/effect/energy_field/proc/Stress(var/severity)
 	strength -= severity
@@ -115,10 +119,7 @@
 	diffuse_check()
 
 /obj/effect/energy_field/CanPass(atom/movable/mover, turf/target, height=1.5, air_group = 0)
-	//Purpose: Determines if the object (or airflow) can pass this atom.
-	//Called by: Movement, airflow.
-	//Inputs: The moving atom (optional), target turf, "height" and air group
-	//Outputs: Boolean if can pass.
+	if(mover?.movement_type & PHASING)
+		return TRUE
 
-	//return (!density || !height || air_group)
 	return (!density || air_group)

code/modules/shieldgen/shieldwallgen.dm

@@ -195,11 +195,14 @@
 	alldir_cleanup()
 	return ..()
 
-/obj/machinery/shieldwallgen/bullet_act(var/obj/projectile/Proj)
-	storedpower -= 400 * Proj.get_structure_damage()
+/obj/machinery/shieldwallgen/bullet_act(obj/projectile/hitting_projectile, def_zone, piercing_hit)
+	. = ..()
+	if(. != BULLET_ACT_HIT)
+		return .
+
+	storedpower -= 400 * hitting_projectile.get_structure_damage()
 	if(power_state >= POWER_STARTING)
-		visible_message(SPAN_WARNING("\The [src]'s shielding sparks as \the [Proj] hits it!"))
-	return ..()
+		visible_message(SPAN_WARNING("\The [src]'s shielding sparks as \the [hitting_projectile] hits it!"))
 
 /obj/shieldwall
 	name = "energy shield"
@@ -255,16 +258,19 @@
 		gen_primary.storedpower -= power_usage / 2
 		gen_secondary.storedpower -= power_usage / 2
 
-/obj/shieldwall/bullet_act(var/obj/projectile/Proj)
+/obj/shieldwall/bullet_act(obj/projectile/hitting_projectile, def_zone, piercing_hit)
+	. = ..()
+	if(. != BULLET_ACT_HIT)
+		return .
+
 	if(needs_power)
 		var/obj/machinery/shieldwallgen/G
 		if(prob(50))
 			G = gen_primary
 		else
 			G = gen_secondary
-		visible_message(SPAN_WARNING("\The [src] wobbles precariously as \the [Proj] impacts it!"))
-		G.storedpower -= 400 * Proj.get_structure_damage()
-	return ..()
+		visible_message(SPAN_WARNING("\The [src] wobbles precariously as \the [hitting_projectile] impacts it!"))
+		G.storedpower -= 400 * hitting_projectile.get_structure_damage()
 
 /obj/shieldwall/ex_act(severity)
 	if(needs_power)
@@ -294,6 +300,8 @@
 /obj/shieldwall/CanPass(atom/movable/mover, turf/target, height=0, air_group=0)
 	if(air_group || (height==0))
 		return TRUE
+	if(mover?.movement_type & PHASING)
+		return TRUE
 	if(istype(mover) && mover.pass_flags & PASSGLASS)
 		return prob(20)
 	else