Revert "Fixes weather's bad image rendering code (#10775)"

This reverts commit dea0bd7.

code/datums/weather/weather.dm

@@ -44,23 +44,9 @@
 	/// This causes the weather to only end if forced to
 	var/perpetual = FALSE
 
-	// cached sprites to go on area overlays.
-	var/mutable_appearance/cached_weather_sprite_start
-	var/mutable_appearance/cached_weather_sprite_process
-	var/mutable_appearance/cached_weather_sprite_end
-
 /datum/weather/New(z_levels)
 	..()
 	impacted_z_levels = z_levels
-	generate_cached_weather_sprites()
-
-/datum/weather/proc/generate_cached_weather_sprites()
-	if(telegraph_overlay)
-		cached_weather_sprite_start = mutable_appearance('icons/effects/weather_effects.dmi', telegraph_overlay, overlay_layer, overlay_plane, color = weather_color)
-	if(weather_overlay)
-		cached_weather_sprite_process = mutable_appearance('icons/effects/weather_effects.dmi', weather_overlay, overlay_layer, overlay_plane, color = weather_color)
-	if(end_overlay)
-		cached_weather_sprite_end = mutable_appearance('icons/effects/weather_effects.dmi', end_overlay, overlay_layer, overlay_plane, color = weather_color)
 
 /datum/weather/proc/telegraph()
 	if(stage == STARTUP_STAGE)
@@ -149,40 +135,23 @@
 	return
 
 /datum/weather/proc/update_areas()
-	var/previous_overlay
-	var/new_overlay
-	switch(stage)
-		if(STARTUP_STAGE)
-			if(cached_weather_sprite_start)
-				new_overlay = cached_weather_sprite_start
-				previous_overlay = TRUE // temporary value. see below.
-		if(MAIN_STAGE)
-			if(cached_weather_sprite_start)
-				previous_overlay = cached_weather_sprite_start
-			if(cached_weather_sprite_process)
-				new_overlay = cached_weather_sprite_process
-		if(WIND_DOWN_STAGE)
-			if(cached_weather_sprite_process)
-				previous_overlay = cached_weather_sprite_process
-			if(cached_weather_sprite_end)
-				new_overlay = cached_weather_sprite_end
-		if(END_STAGE)
-			if(cached_weather_sprite_end)
-				previous_overlay = cached_weather_sprite_end
-				new_overlay = TRUE // temporary value. see below.
-
-	// we won't iterate all areas unnecesarily
-	if(!previous_overlay && !new_overlay)
-		return
-
-	// removing TRUE value because we don't want typecheck every iteration from for loop
-	if(previous_overlay == TRUE)
-		previous_overlay = null
-	if(new_overlay == TRUE)
-		new_overlay = null
-
-	for(var/area/each_area as anything in impacted_areas)
-		if(previous_overlay)
-			each_area.cut_overlay(previous_overlay)
-		if(new_overlay)
-			each_area.add_overlay(new_overlay)
+	for(var/V in impacted_areas)
+		var/area/N = V
+		N.layer = overlay_layer
+		N.plane = overlay_plane
+		N.icon = 'icons/effects/weather_effects.dmi'
+		N.color = weather_color
+		switch(stage)
+			if(STARTUP_STAGE)
+				N.icon_state = telegraph_overlay
+			if(MAIN_STAGE)
+				N.icon_state = weather_overlay
+			if(WIND_DOWN_STAGE)
+				N.icon_state = end_overlay
+			if(END_STAGE)
+				N.color = null
+				N.icon_state = ""
+				N.icon = 'icons/turf/areas.dmi'
+				N.layer = initial(N.layer)
+				N.plane = initial(N.plane)
+				N.set_opacity(FALSE)