Update lib/tilesheet.lua

lib/tilesheet.lua

@@ -36,10 +36,26 @@ local tilesheet.load = function(data_or_path)
     tile_image = load_image(data_or_path)
   end
 
+  -- this mess feels kinda wasteful/repetitive
+  local image_width, image_height = tile_image:getDimensions()
+  local tile_usage = {}
+  for x = 1, image_width / tile_size do
+    tile_usage[x] = {}
+    for y = 1, image_height / tile_size do
+      tile_usage[x][y] = false
+    end
+  end
+  if type(data_or_path) == "table" then
+    for name, tile_data in pairs(data_or_path.tiles) do
+      tile_usage[tile_data.x][tile_data.y] = true
+    end
+  end
+
   tilesheet.active_sheet = {
     image = tile_image,
     size = tile_size,
     tiles = tiles,
+    tile_usage = tile_usage,
   }
 
   return tiles