private void saveSpritesheet() {
		
		File file;
		
		int i = 0;
		
		while(true) {			
			file = new File(App.modelDir, "out/spritesheet"+(i==0?"":"-"+i)+".png");
			if(!file.exists()) break;
			i++;
		}
		
		// save to disk
		try {
			ImageIO.write(image, "PNG", file);
		} catch (IOException e) {
			Log.e("Failed to save screenshot.", e);
		}
	}