GPU-powered path tracing, take two
This image was generated with my GPU. I added minimal texture support, for the floor plane, and as an environment map (basically, when a ray does not intersect any object, its direction vector is used to sample the environment map and that is used as an approximate lighting value). I was impressed at the convergence rate, the noise disappeared in literally less than ten seconds thanks to the radiance contribution from the entire environment map.
If you are wondering why the sky looks overexposed, it's because I was using a low dynamic range environment map (so it was necessary to sort of fake the high dynamic range by raising the color values to some exponent, making the sky look weird). With a proper HDR image this would not occur as the sun in the environment map would naturally have a high radiance contribution whereas the rest of the image would have "standard" contributions, which would work better.
But high-resolution HDR images are hard to find and I need to find a way to parse them as well. Perhaps for the next entry!
A HQ (2048x2048) version of this render is available in my Gallery album. Beware - it's 10MB large!