Fixes overmap loop homing (BeeStation#2708)

code/modules/projectiles/projectile.dm

@@ -820,8 +820,14 @@
 
 /obj/item/projectile/proc/process_homing() //Nsv13 - Enhanced the performance of this entire proc.
 	if(QDELETED(homing_target)) //NSV13 - Changed proc to be less performance intensive
-		return FALSE
-	var/targetAngle = get_angle(src, homing_target)
+		if(homing_target) //Bla bla refclearing. Necessary evil. (Probably not worth the hassle of handling this via comsig, so this is here instead)
+			homing_target = null
+		return FALSE //Hi, Delta from the past here, future one. We don't just disable homing entirely here because some projectiles might be able to reassess targets.
+	var/targetAngle
+	if(z && SSmapping.level_trait(z, ZTRAIT_OVERMAP)) //This bit of performance cost should be worth making these track properly.
+		targetAngle = overmap_angle(src, homing_target)
+	else
+		targetAngle = get_angle(src, homing_target)
 	var/angle = closer_angle_difference(Angle, targetAngle)
 	next_homing_process = world.time + homing_delay
 	setAngle(Angle + CLAMP(angle, -homing_turn_speed, homing_turn_speed))

nsv13/code/modules/projectiles/overmap.dm

@@ -3,9 +3,10 @@
 	var/valid_angle = 0 //Angle the projectile can track at
 	var/shotdown_effect_type = /obj/effect/temp_visual/impact_effect/torpedo
 
+//Hey look, all this logic doesn't work! I love finding these things.
 /obj/item/projectile/guided_munition/process_homing(atom/A)
 	. = ..()
 	var/simplify_Angle = SIMPLIFY_DEGREES(Angle)
-	var/simplify_targetAngle = SIMPLIFY_DEGREES(targetAngle)
+	var/simplify_targetAngle = SIMPLIFY_DEGREES(targetAngle) //<< This var is never actually modified because [local var] supercedes [obj var] unless src is used. Personally, I'm unsure if we actually WANT it fixed. ~Delta
 	if(simplify_targetAngle > simplify_Angle + valid_angle)
 		homing = FALSE