[MIRROR] Overlay lighting component (#469)

* Overlay lighting component (#52413)

Sparks no longer lag, projectile beams move super smoothly, same with mobs and whatnot. This also allows for easy expansion into directional lights, field-of-view, wee-woo rotating lights or whatever.

It does have a downside: things right-clicked or checked through the alt+click tab will show the light overlay:


This is a BYOND limitation, very well worth it IMO.

🆑
add: Smooth movable lighting system implemented. Projectiles, sparks, thrown flashlights or moving mobs with lights should be much smoother and less laggy.
balance: Light sources no longer stack in range, though they still do in intensity.
/🆑

* Overlay lighting component

Co-authored-by: Rohesie <rohesie@gmail.com>

code/modules/projectiles/gun.dm

@@ -398,9 +398,7 @@
 			if(!user.transferItemToLoc(I, src))
 				return
 			to_chat(user, "<span class='notice'>You click [S] into place on [src].</span>")
-			if(S.on)
-				set_light(0)
-			gun_light = S
+			set_gun_light(S)
 			update_gunlight()
 			alight = new(src)
 			if(loc == user)
@@ -508,12 +506,30 @@
 	if(!gun_light)
 		return
 	var/obj/item/flashlight/seclite/removed_light = gun_light
-	gun_light = null
+	set_gun_light(null)
 	update_gunlight()
 	removed_light.update_brightness()
 	QDEL_NULL(alight)
 	return TRUE
 
+
+///Called when gun_light value changes.
+/obj/item/gun/proc/set_gun_light(obj/item/flashlight/seclite/new_light)
+	if(gun_light == new_light)
+		return
+	. = gun_light
+	gun_light = new_light
+	if(gun_light)
+		gun_light.set_light_flags(gun_light.light_flags | LIGHT_ATTACHED)
+		if(gun_light.loc != src)
+			gun_light.forceMove(src)
+	else if(.)
+		var/obj/item/flashlight/seclite/old_gun_light = .
+		old_gun_light.set_light_flags(old_gun_light.light_flags & ~LIGHT_ATTACHED)
+		if(old_gun_light.loc == src)
+			old_gun_light.forceMove(get_turf(src))
+
+
 /obj/item/gun/ui_action_click(mob/user, actiontype)
 	if(istype(actiontype, alight))
 		toggle_gunlight()
@@ -526,19 +542,13 @@
 
 	var/mob/living/carbon/human/user = usr
 	gun_light.on = !gun_light.on
+	gun_light.update_brightness()
 	to_chat(user, "<span class='notice'>You toggle the gunlight [gun_light.on ? "on":"off"].</span>")
 
 	playsound(user, 'sound/weapons/empty.ogg', 100, TRUE)
 	update_gunlight()
 
 /obj/item/gun/proc/update_gunlight()
-	if(gun_light)
-		if(gun_light.on)
-			set_light(gun_light.brightness_on)
-		else
-			set_light(0)
-	else
-		set_light(0)
 	update_icon()
 	for(var/X in actions)
 		var/datum/action/A = X

code/modules/projectiles/guns/energy/energy_gun.dm

@@ -26,7 +26,7 @@
 	flight_y_offset = 13
 
 /obj/item/gun/energy/e_gun/mini/Initialize()
-	gun_light = new /obj/item/flashlight/seclite(src)
+	set_gun_light(new /obj/item/flashlight/seclite(src))
 	return ..()
 
 /obj/item/gun/energy/e_gun/stun

code/modules/projectiles/projectile/beams.dm

@@ -3,13 +3,15 @@
 	icon_state = "laser"
 	pass_flags = PASSTABLE | PASSGLASS | PASSGRILLE
 	damage = 20
-	light_range = 2
 	damage_type = BURN
 	hitsound = 'sound/weapons/sear.ogg'
 	hitsound_wall = 'sound/weapons/effects/searwall.ogg'
 	flag = "laser"
 	eyeblur = 2
 	impact_effect_type = /obj/effect/temp_visual/impact_effect/red_laser
+	light_system = MOVABLE_LIGHT
+	light_range = 2
+	light_power = 1
 	light_color = COLOR_SOFT_RED
 	ricochets_max = 50	//Honk!
 	ricochet_chance = 80
@@ -17,6 +19,7 @@
 	wound_bonus = -20
 	bare_wound_bonus = 10
 
+
 /obj/projectile/beam/laser
 	tracer_type = /obj/effect/projectile/tracer/laser
 	muzzle_type = /obj/effect/projectile/muzzle/laser