Lara Croft has fabulous new hair, and so can everybody in games thanks to the graphics boffins in the AMD laboratoire. That new TressFX technology hinted at on the AMD blog yesterday was about hair after all, and today AMD can reveal that they've figured out a very clever way of making hair look realistic and wavy and nice rather than blocky and plastic and rubbish. It's a tiny revolution happening across virtual scalps, and it's all thanks to a little something AMD like to call the per-pixel linked-list data structures of order independent transparencies. That's hair science to you and me!
AMD outline the challenge of rendering decent looking hairdos thusly: "Realistic hair is one of the most complex and challenging materials to accurately reproduce in real-time. Convincingly recreating a head of lively hair involves drawing tens of thousands of tiny and individual semi-transparent strands, each of which casts complex shadows and requires anti-aliasing. Even more challengingly, these calculations must be updated dozens of times per second to synchronize with the motion of a character."
Unfortunately, exactly how AMD have managed to overcome this problem remains a total mystery, despite their attempts to explain. "TressFX Hair revolutionizes Lara Croft’s locks by using the DirectCompute programming language to unlock the massively-parallel processing capabilities of the Graphics Core Next architecture, enabling image quality previously restricted to pre-rendered images. Building on AMD’s previous work on Order Independent Transparency (OIT), this method makes use of Per-Pixel Linked-List (PPLL) data structures to manage rendering complexity and memory usage."
Lara's hair will be swished about realistically by her own head movements, gravity, wind and her hairstyle (to which individual strands will attempt to adhere, springing back into position like memoryfoam mattresses or those glasses frames you can crumple up). There's also per-strand collision detection, meaning Lara's hair won't get stuck inside her face or start clipping through boulders mid-cutscene. Check out the blog post for some nice comparison shots.
AMD cards featuring Graphics Core Next technology will be able to carry out this feat of processing, with no word whether the hair-swishing technology will be made available to Nvidia owners.