tilemap no longer uses ppu

prosperon/tilemap.cm

@@ -5,10 +5,11 @@ function tilemap()
   this.tiles = [];
   this.offset_x = 0;
   this.offset_y = 0;
-  this.ppu = 32
   this.layer = 0;  // Default layer for scene tree sorting
   this._geometry_cache = {};  // Cache actual geometry data by texture
   this._dirty = true;
+  this.scale_x = 1
+  this.scale_y = 1
   return this;
 }
 
@@ -110,17 +111,13 @@ tilemap.prototype =
           var textureKey = imageToKey.get(tile);
           
           if (!textureGroups[textureKey]) {
-            // compute world-unit size of one tile of this texture
-            var tile_wu = tile.width / this.ppu;
-            var tile_hu = tile.height / this.ppu;
-            
             textureGroups[textureKey] = {
               tiles: [],
               image: tile,  // Store the image object
               offset_x: this.offset_x,
               offset_y: this.offset_y,
-              size_x: tile_wu,
-              size_y: tile_hu
+              size_x: this.scale_x,
+              size_y: this.scale_y
             };
           }
           textureGroups[textureKey].tiles.push({