Optimize wall/fog rendering

nodes/fog_renderer.gd

@@ -5,39 +5,35 @@ extends Node2D
 ## that is not part of any room. Future: drive visibility from map state.
 
 const TILE_SIZE := 100.0
+## Fog tile region in aux_terrain.BMP
 const FOG_RECT := Rect2(53, 53, 100, 100)
 
 @export var atlas_texture: Texture2D
 
+var _fog_tiles: PackedVector2Array = []
+
 
 func draw_fog_for_layout(map_layout: MapLayout) -> void:
-	_clear()
+	_fog_tiles.clear()
 	if not map_layout or not atlas_texture:
+		queue_redraw()
 		return
 	for y in map_layout.size.y:
 		for x in map_layout.size.x:
 			var tile := Vector2i(x, y)
 			if map_layout.is_tile_valid(tile):
 				continue
-			_create_fog_sprite(Vector2(tile) * TILE_SIZE)
+			_fog_tiles.append(Vector2(tile) * TILE_SIZE)
+	queue_redraw()
 
 
-func _clear() -> void:
-	for child in get_children():
-		child.queue_free()
-
-
-func _create_fog_sprite(pos: Vector2) -> void:
-	var atlas := AtlasTexture.new()
-	atlas.atlas = atlas_texture
-	atlas.region = FOG_RECT
-
-	var sprite := Sprite2D.new()
-	sprite.texture = atlas
-	sprite.centered = false
-	sprite.position = pos
-	sprite.scale = Vector2(
-		TILE_SIZE / FOG_RECT.size.x,
-		TILE_SIZE / FOG_RECT.size.y,
-	)
-	add_child(sprite)
+func _draw() -> void:
+	if not atlas_texture:
+		return
+	var dest_size := Vector2(TILE_SIZE, TILE_SIZE)
+	for pos in _fog_tiles:
+		draw_texture_rect_region(
+			atlas_texture,
+			Rect2(pos, dest_size),
+			FOG_RECT,
+		)