SaveFrameBufferRoutine.java

public FileHandle saveFrameBuffer (FrameBuffer frameBuffer) {
	FileHandle handle = Gdx.files.external("myscreenshot.png");

	frameBuffer.bind();

	Pixmap pixmap = new Pixmap(Gdx.graphics.getWidth(), Gdx.graphics.getHeight(), Pixmap.Format.RGBA8888);
	ByteBuffer pixels = pixmap.getPixels();
	Gdx.gl.glReadPixels(0, 0, frameBuffer.getWidth(), frameBuffer.getHeight(), GL20.GL_RGBA, GL20.GL_UNSIGNED_BYTE, pixels);

	try {
		PixmapIO.PNG writer = new PixmapIO.PNG((int)(pixmap.getWidth() * pixmap.getHeight() * 1.5f)); // Guess at deflated size.
		try {
			writer.setFlipY(true);
			writer.write(handle, pixmap);
		} finally {
			writer.dispose();
		}
	} catch (IOException ex) {
		throw new GdxRuntimeException("Error writing PNG: " + handle, ex);
	}

	frameBuffer.dispose();
	pixmap.dispose();
	return handle;
}