public boolean[][] createWallMap(TiledMap map) {
	if (map == null)
	    return null;
	
	int layer = map.getLayerIndex("Tile Layer 3");
	boolean[][] wallMap = new boolean[32][24];
	
	for (int j=0; j<wallMap[0].length; ++j)
	    for (int i=0; i<wallMap.length; ++i)
		if (map.getTileId(i, j, layer) != 0)
		    wallMap[i][j] = true;
	
	return wallMap;
    }