In testing some new code involving box-intersection I prepared a Cornell Box with a glass block, and first question is "is this right?". As usual, I am not sure. Here's the picture (done with a bajillion samples so I wont get fooled by outliers):
It's smooth anyway. The glass is plausible to my eye. The strangest thing is how bright the bottom of the glass block is. Is it right? At first I figured bug. But maybe that prism operates as a light tunnel (like fiber optics) so the bottom is the same color as a diffuse square on the prism top would be. So now I will test that hypothesis somehow (google image search? find a glass block?) and if that phenomenon is right and of about the right magnitude, I'll declare victory.