Icare3D has publshed a small OpenGL 4.0 demo (with code source and executable) that shows an implementation of the A-buffer algorithm. You can download the demo HERE. This demo works on GTX 400 series only. What is an A-buffer? In its simplest form, an A-buffer is a memory buffer that stores a list of fragments per pixel. A Z-buffer stores only the nearest fragment for each pixel while an A-buffer