A note about performance

While the new shader generates quite nice results, we also want the program to run smooth. Using 20 number of steps for both linear and binary search gives us steady 60 FPS on my old desktop with nVidia GTX 460 and Intel Q9550 @ 3.9 ghz (2560x1440 resolution). Increasing to 30 binary search steps immediately results in FPS drops down to 40 FPS. It's really hard to spot any difference between using 30 and 20 steps for binary search, there is a bigger visual difference between 20 and 10. 20 steps seems like a good number.