Am Thu, 13 Mar 2008 08:15:23 +0100 schrieb Christoph Hormann:
> 
> is this cache per thread or global?  The former would make more sense
> since the rays are only correlated in a thread and not between several
> ones.  Also it would make sense to exclude radiosity rays.
> 
There is one cache per thread per isosurface via 
boost::thread_specific_ptr. I figured out that the number of cache 
entries should be kept smaller than (number of lightsources + number of 
reflective textures on the isosurface). So only one cache entry is enough 
for most simple scenes with non-reflective isosurfaces.

> 
> Sounds much like the sphere tracing technique to me - i once tried this
> and it did not seem to be have a significant advantage to me.

You are right. I did not know what this technique was called. The current 
POV implementation finds a root on an interval [t_min, t_max] in a fixed 
number of recursions. I tried to lower this number somehow but it did not 
work out well.

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