March 8th, 2008

Free direction Tunnel effect

After finalizing the Tunnel Effect, I wanted to go for something a little bit harder and I came across this fantastic text by BlackAxe / KoLOr (1997).

Seriously, this paper is so well written that I have nothing to add. Only that I learned the golden rule in computer graphic:

Perception is reality..

Using raytracing technique, you can get a "Free direction Tunnel effect", much more sophiticated than the first Tunnel. The only hard part to understand (and I guess it was intentional) is when it comes to "interpolation", which is the essence of the trick.

Try it and source

First implementation

If you follow the procedure described you get a raytraced Free direction Tunnel.....running at 7 frames per secondes: You can check it out Here.
Beautiful but slow.

Second implementation with interpolations

The second interpolation only cast a ray each 8 pixels and then interpolate the texture. The result is slighty less pretty but 10x faster ! Since the tunnel is moving fast, the lost of quality is almost invisible compared to the speed gain :



Fabien Sanglard @2008