GDC Videos & PS3 Raytracing | PS3Blog.net
If you’ve been aching for some actual video footage from Mr. Phil Harrison’s keynote at GDC, then Joysiq is about to give you some happy happy joy joy. Well, a little at any rate. They have links to some Warhawk video footage and a technical demonstration from Motorstorm.
Just one thing to note. I’ve heard people talk about the WarHawk demo and claim that PS3 does raytracing in realtime. The dude in the demo says that the volumetric cloudes were done with raytracing. I just want to point out that this is a totally different kind of raytracing than is normally discussed. Normally raytracing is where a ray is cast from the virtual eye position, through the virtual pixel on the screen, and into the scene. Then the ray bounces around a lot, often spawning hundreds of other rays to collect info, and all those primary and spawned rays contribute to the final colour of the pixel. This gives cool effects like mirror balls etc.
Volumetric rendering of clouds is different. One ray is shot into the scene per pixel, and no rays get spawned off that one. Then the ray is marched to accumulate cloud information. This is a lot less expensive than fully raytracing a scene as most people know it.
So no, the PS3 can not do realtime raytracing of complicated scenes.
Oh, are more video links from readers (thanks!):