Cut up an image into chunks

gistfile1.hx

			var bitmapData = Assets.getBitmapData(bitmapPath);

			_fullWidth = bitmapData.width;
			_fullHeight = bitmapData.height;
			_chunkSize = chunkSize;
			_lastChunkRect = new Rectangle();
			_currentChunkRect = new Rectangle();

			// it's different! remove the old cached chunk data
			FileUtils.rmdir(_cachePath);
			FileUtils.mkdir(_cachePath);

			// generate bitmap files
			var chunksAcross = Math.floor(bitmapData.width/chunkSize);
			var chunksDown = Math.floor(bitmapData.height/chunkSize);

			if (chunksAcross <= 1 && chunksDown <= 1) return; // todo handle this case better

			var chunk = new BitmapData(chunkSize, chunkSize);

			for (y in 0...chunksDown)
			{
				for (x in 0...chunksAcross)
				{
					// save this chunk of the bitmap as a separate chunkfile
					var sourceRect = new Rectangle(x * chunkSize, y * chunkSize, chunkSize, chunkSize);
					var destRect = new Rectangle(0, 0, chunkSize, chunkSize);

					chunk.copyPixels(bitmapData, sourceRect, new Point(0,0));
					var pngChunkData = chunk.encode("png");

					sys.io.File.saveBytes(chunkFilename(x, y), pngChunkData);
					trace('generating: ' + _cachePath + '/' + chunkFilename(x, y) + ' (' + chunk.width + 'x' + chunk.height + ')');
				}
			}