[MIRROR] Infrared Emitters use beam datums (As God intended)

code/__DEFINES/dcs/signals/signals_beam.dm

@@ -1,3 +1,12 @@
 /// Called before beam is redrawn
 #define COMSIG_BEAM_BEFORE_DRAW "beam_before_draw"
 	#define BEAM_CANCEL_DRAW (1 << 0)
+
+/// Sent to a beam when an atom enters any turf the beam covers: (obj/effect/ebeam/hit_beam, atom/movable/entered)
+#define COMSIG_BEAM_ENTERED "beam_entered"
+
+/// Sent to a beam when an atom exits any turf the beam covers: (obj/effect/ebeam/hit_beam, atom/movable/exited)
+#define COMSIG_BEAM_EXITED "beam_exited"
+
+/// Sent to a beam when any turf the beam covers changes: (list/datum/callback/post_change_callbacks)
+#define COMSIG_BEAM_TURFS_CHANGED "beam_turfs_changed"

code/datums/beam.dm

@@ -163,16 +163,16 @@
 			Pixel_y = round(cos(Angle)+32*cos(Angle)*(N+16)/32)
 
 		//Position the effect so the beam is one continous line
-		var/a
+		var/final_x = segment.x
+		var/final_y = segment.y
 		if(abs(Pixel_x)>32)
-			a = Pixel_x > 0 ? round(Pixel_x/32) : CEILING(Pixel_x/32, 1)
-			segment.x += a
+			final_x += Pixel_x > 0 ? round(Pixel_x/32) : CEILING(Pixel_x/32, 1)
 			Pixel_x %= 32
 		if(abs(Pixel_y)>32)
-			a = Pixel_y > 0 ? round(Pixel_y/32) : CEILING(Pixel_y/32, 1)
-			segment.y += a
+			final_y += Pixel_y > 0 ? round(Pixel_y/32) : CEILING(Pixel_y/32, 1)
 			Pixel_y %= 32
 
+		segment.forceMove(locate(final_x, final_y, segment.z))
 		segment.pixel_x = origin_px + Pixel_x
 		segment.pixel_y = origin_py + Pixel_y
 		CHECK_TICK
@@ -194,6 +194,7 @@
 		return
 	var/mutable_appearance/emissive_overlay = emissive_appearance(icon, icon_state, src)
 	emissive_overlay.transform = transform
+	emissive_overlay.alpha = alpha
 	. += emissive_overlay
 
 /obj/effect/ebeam/Destroy()
@@ -202,9 +203,69 @@
 
 /obj/effect/ebeam/singularity_pull()
 	return
+
 /obj/effect/ebeam/singularity_act()
 	return
 
+/// A beam subtype used for advanced beams, to react to atoms entering the beam
+/obj/effect/ebeam/reacting
+	/// If TRUE, atoms that exist in the beam's loc when inited count as "entering" the beam
+	var/react_on_init = FALSE
+
+/obj/effect/ebeam/reacting/Initialize(mapload, beam_owner)
+	. = ..()
+	var/static/list/loc_connections = list(
+		COMSIG_ATOM_ENTERED = PROC_REF(on_entered),
+		COMSIG_ATOM_EXITED = PROC_REF(on_exited),
+		COMSIG_TURF_CHANGE = PROC_REF(on_turf_change),
+	)
+	AddElement(/datum/element/connect_loc, loc_connections)
+
+	if(!isturf(loc) || isnull(owner) || mapload || !react_on_init)
+		return
+
+	for(var/atom/movable/existing as anything in loc)
+		beam_entered(existing)
+
+/obj/effect/ebeam/reacting/proc/on_entered(datum/source, atom/movable/entered)
+	SIGNAL_HANDLER
+
+	if(isnull(owner))
+		return
+
+	beam_entered(entered)
+
+/obj/effect/ebeam/reacting/proc/on_exited(datum/source, atom/movable/exited)
+	SIGNAL_HANDLER
+
+	if(isnull(owner))
+		return
+
+	beam_exited(exited)
+
+/obj/effect/ebeam/reacting/proc/on_turf_change(datum/source, path, new_baseturfs, flags, list/datum/callback/post_change_callbacks)
+	SIGNAL_HANDLER
+
+	if(isnull(owner))
+		return
+
+	beam_turfs_changed(post_change_callbacks)
+
+/// Some atom entered the beam's line
+/obj/effect/ebeam/reacting/proc/beam_entered(atom/movable/entered)
+	SHOULD_CALL_PARENT(TRUE)
+	SEND_SIGNAL(owner, COMSIG_BEAM_ENTERED, src, entered)
+
+/// Some atom exited the beam's line
+/obj/effect/ebeam/reacting/proc/beam_exited(atom/movable/exited)
+	SHOULD_CALL_PARENT(TRUE)
+	SEND_SIGNAL(owner, COMSIG_BEAM_EXITED, src, exited)
+
+/// Some turf the beam covers has changed to a new turf type
+/obj/effect/ebeam/reacting/proc/beam_turfs_changed(list/datum/callback/post_change_callbacks)
+	SHOULD_CALL_PARENT(TRUE)
+	SEND_SIGNAL(owner, COMSIG_BEAM_TURFS_CHANGED, post_change_callbacks)
+
 /**
  * This is what you use to start a beam. Example: origin.Beam(target, args). **Store the return of this proc if you don't set maxdist or time, you need it to delete the beam.**
  *
@@ -221,5 +282,3 @@
 	var/datum/beam/newbeam = new(src,BeamTarget,icon,icon_state,time,maxdistance,beam_type, beam_color, emissive, override_origin_pixel_x, override_origin_pixel_y, override_target_pixel_x, override_target_pixel_y )
 	INVOKE_ASYNC(newbeam, TYPE_PROC_REF(/datum/beam/, Start))
 	return newbeam
-
-

code/modules/antagonists/heretic/magic/fire_blast.dm

@@ -31,7 +31,7 @@
 
 /datum/action/cooldown/spell/charged/beam/fire_blast/send_beam(atom/origin, mob/living/carbon/to_beam, bounces = 4)
 	// Send a beam from the origin to the hit mob
-	origin.Beam(to_beam, icon_state = "solar_beam", time = beam_duration, beam_type = /obj/effect/ebeam/fire)
+	origin.Beam(to_beam, icon_state = "solar_beam", time = beam_duration, beam_type = /obj/effect/ebeam/reacting/fire)
 
 	// If they block the magic, the chain wont necessarily stop,
 	// but likely will (due to them not catching on fire)
@@ -141,25 +141,11 @@
 	owner.adjustStaminaLoss(2 * tick_damage * seconds_between_ticks)
 
 // The beam fireblast spits out, causes people to walk through it to be on fire
-/obj/effect/ebeam/fire
+/obj/effect/ebeam/reacting/fire
 	name = "fire beam"
 
-/obj/effect/ebeam/fire/Initialize(mapload)
+/obj/effect/ebeam/reacting/fire/beam_entered(atom/movable/entered)
 	. = ..()
-	var/static/list/loc_connections = list(
-		COMSIG_ATOM_ENTERED = PROC_REF(on_entered),
-	)
-	AddElement(/datum/element/connect_loc, loc_connections)
-
-	if(!isturf(loc) || mapload) // idk if this would ever be maploaded but you never know
-		return
-
-	for(var/mob/living/living_mob in loc)
-		on_entered(entered = living_mob)
-
-/obj/effect/ebeam/fire/proc/on_entered(datum/source, atom/movable/entered)
-	SIGNAL_HANDLER
-
 	if(!isliving(entered))
 		return
 	var/mob/living/living_entered = entered