Have you seen this? (real-time raytracing)

Real time ray-tracing on the GPU, quite amazing!
Interesting also how they implemented noise to keep performance up under stress.

They didn’t implement noise. That is what happens when you under-sample using raytracing.

this is pretty cool. I don’t really know much about ray-tracing but it’s basically just simulating light ray right? :-\ All I know is the lighting looks really good.

[quote]They didn’t implement noise. That is what happens when you under-sample using raytracing.
[/quote]
They explained on the blog that there is what they call a ‘russian roulette-like mechanism’ going on for the more demanding rays when needed to keep it running at 30fps, and that on faster machines there’s less noise.
So while true that this results in under-sampling for those pixels, there seems to be a random element implemented there on some level (unless I misunderstood something).

Also called Monte-Carlo algorithms. Which is used for any algorithm which uses random sampling to come to the result.

There is also a monte-carlo algo to calculate PI. Just create random points in a square and calculate the percentage of points which lie in the circle with the same radius as the length of the square. Then you can calculate PI from the ratio between the area of the square and circle.

Thanks for sharing, looks cool.