scott wrote:
>> I was thinking more along the lines of each surface possibly having a 
>> different code path for computing illumination. Rays in the same 
>> bundle can't take different code paths.
> 
> Sure they can, you just have an "if" in the shader code based on some 
> flag in the ray data.

Problem: when you come to a branch, all units in that block have to take 
the same branch.

Thus, branching is discouraged.

>> Indeed, that's where I read about the render queue approach. (No, I 
>> don't remember where *exactly*.)
> 
> Damn.  If you think up *anything* you think is new, you can be 
> guaranteed that someone else somewhere has already thought of it :-)  
> The internet just makes it easy to find that person!

I know I saw a whitepaper on the render queue method back in the 90s, 
but I don't remember the author.  In fact, most of the work done on 
computers with graphics was theorized back in the 70s and 80s, but is 
only in the last 5 or 10 years being widely implemented due to 
sufficient hardware support now being available.

...Chambers

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