[MIRROR] Only blend areas when it's actually needed (#6978)

* Only blend areas when it's actually needed (#60237)

* Only blend areas when it's actually needed

* Respect varedits

* Only blend areas when it's actually needed

Co-authored-by: TiviPlus <57223640+TiviPlus@users.noreply.github.com>

code/game/area/areas.dm

@@ -167,9 +167,8 @@ GLOBAL_LIST_EMPTY(teleportlocs)
 
 	. = ..()
 
-	blend_mode = BLEND_MULTIPLY // Putting this in the constructor so that it stops the icons being screwed up in the map editor.
-
 	if(!IS_DYNAMIC_LIGHTING(src))
+		blend_mode = BLEND_MULTIPLY
 		add_overlay(/obj/effect/fullbright)
 
 	reg_in_areas_in_z()

code/modules/lighting/lighting_area.dm

@@ -10,12 +10,14 @@
 
 	if (IS_DYNAMIC_LIGHTING(src))
 		cut_overlay(/obj/effect/fullbright)
+		blend_mode = BLEND_DEFAULT
 		for (var/turf/T in src)
 			if (IS_DYNAMIC_LIGHTING(T))
 				T.lighting_build_overlay()
 
 	else
 		add_overlay(/obj/effect/fullbright)
+		blend_mode = BLEND_MULTIPLY
 		for (var/turf/T in src)
 			if (T.lighting_object)
 				T.lighting_clear_overlay()