For those that do not know me: My name is Jacco Bikker, also known as 'Phantom'. I work as '3D tech guy' at Overloaded, a company that develops and distributes games for mobile phones. I specialize at 3D Symbian games, which require highly optimized fixed-point, non-HW-accelerated 3D engines, crammed into 250Kb installers. So basically I'm having fun.
As software rendering used to be my spare time activity, I was looking for something else. I tried some AI, which was great fun, and recently I dove into a huge pile of research papers on raytracing and related topics; such as global illumination, image based lighting, photon maps and so on.
One document especially grabbed my attention. It's titled: "State-of-the-Art in Interactive Ray Tracing", and was written by Wald & Slusallek. I highly recommend this paper. Basically, it summarizes recent efforts to improve the speed of raytracing, and adds a couple of tricks too. But it starts with a list of benefits of raytracing over rasterization-based algorithms. And one of those benefits is that when you go to extremes, raytracing is actually faster than rasterizing. And they prove it: Imagine a huge scene, consisting of, say, 50 million triangles. Toss it at a recent GeForce with enough memory to store all those triangles, and write down the frame rate. It will be in the vicinity of 2-5. If it isn't, double the triangle count. Now, raytrace the same scene. These guys report 8 frames per second on a dual PIII/800. Make that a quad PIII/800 and the speed doubles. Raytracing scales linearly with processing power, but only logarithmically with scene complexity.
Now that I got your attention, I would like to move on to the intended contents of this crash course in raytracing.
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