>>7
IHBT
>>8
Fuck Intel.
>>10
Yes, ray-casting is just ray-tracing with only one collision per ray. No bouncing of rays off of surfaces to compute inter-reflection and radiance. You can use deferred shading and global illumination techniques to better approximate inter-reflection and radiance with
MUCH better performance.
And no, a cloud of 20 wouldn't necessarily perform the task better. Ray-tracing does not scale at all. You are completely misunderstanding what I mean when I say it's limited by memory latency and cache coherency. Adding more RAM doesn't improve memory latency. Adding more machines doesn't improve memory latency. In fact, adding faster RAM doesn't improve memory, it actually makes it worse. The only thing you can do really is improve the size of the on-die cache on the CPU, but there are even limitation as to what you can do there.
When you think about how ray-tracing works, you cast a ray out into the scene and find where it first intersects with the geometry. This pulls a whole bunch of model data into the CPU's cache, and when it finds a collision, the data representing the surface that was intersected is left hot in the cache. But when you recurse and bounce the ray off of it, it goes in a completely different direction and everything in the cache ends up getting thrown out. And then it happens again, and again! Extremely poor scalability.
With ray-casting, you cast your ray, get an intersection, leave the model hot in the cache, and then cast the ray for the next pixel over from the current, and there's a good chance it will end up intersecting with the same surface as the previous ray, and therefore the cache doesn't have to be invalidated and reloaded with different data as often.
If you aren't really familiar with the intricacies and performance characteristics of memory and cache coherency on modern CPU architectures, then I suggest you read ``What Every Programmer Should Know About Memory'':
http://www.akkadia.org/drepper/cpumemory.pdf
Yes, you could design specialized hardware that is better at ray-tracing then a general purpose computer, but that's a big waste of silicon. You will get better quality real-time graphics and be able to render a lot more per frame if you invest that silicon into conventional GPUs and use rasterization or ray-casting in conjunction with deferred shading and scene composition.