John Carmack made a couple of interesting posts to his .plan file recently. If you're interested in seeing what the best 3d graphics programmer in the world is doing and thinking, check out his <a href="http://www.earthli.com/users/marco/carmack_2002_02_11.php">.plan from February 11, 2002</a>. In it, he talks about implementing the Radeon-specific rendering instructions for the DOOM engine. Of particular interest to those in the market for a video card when his next engine comes out is this quote: <iq>Do not buy a GeForce4-MX for Doom.</iq> He goes into some detail as to why, but it basically boils down to the fact that the card is named '4' for marketing reasons only and is <i>not</i> better than a GeForce3. It's always interesting to read his posts, if only to let you know that someone like him exists and take heart from that. In a post from March 15, 2002 he mentions an article on the <a href="http://www.nvidia.com">NVidia</a> site called <a href="http://developer.nvidia.com/view.asp?IO=robust_shadow_volumes">Practical and Robust Shadow Volumes</a>. That article includes a reference to an email Carmack sent explaining his <a href="http://cvs1.nvidia.com/OpenGL/doc/whitepapers/CarmackOnShadowVolumes.txt">experiments with shadow volumes</a>. He starts the letter with: <bq>I solved this in a way that is so elegant you just won't believe it. Here is a description that I posted to a private mailing list...</bq> ...so you just know it's going to be way over your head. It's still a nice look at how an engineer approaches a solution. If you read far enough, you get to this gem (emphasis added): <bq>Unfortunately, the quality just isn't good enough unless you use extremely high resolution shadow maps ... For comparison, <i>Pixar</i> will commonly use 2K or 4K shadow maps...</bq> That's right, he just compared his renderer's quality to Pixar. The fact that he said it was not <iq>good enough</iq> in no way diminishes my anticipation for his next game. The paper, <a href="http://cvs1.nvidia.com/OpenGL/doc/whitepapers/RobustShadowVolumes.pdf">Practical and Robust Shadow Volumes</a> (PDF - 2.1MB) discusses shadow volumes in more detail, providing sample source code, a hideously technical description and some purty screenshots of actual working code.