On 19-1-2010 22:51, nemesis wrote:
> Sabrina Kilian escreveu:
>> I have stated my intention to look into this...
> 
> ...and then proceeded to precisely put up with all those excuses about 
> non-triangle surfaces and all other povray features that have no such 
> use for a GPU.  I thought you changed your mind.
> 
> I'm not ranting, nor whining, nor demanding anything.  I just thought 
> most would here would be glad to know GPU's are finally there for 
> raytracing speedup.  I was wrong, as always.

Ok, this is going to be my last try: everybody here would love POV to be 
faster. Only based on the information we have got, GPU programming won't 
work at the moment. As soon as it is feasible somebody will implement 
things.
You seem to be surprised again and again that even if we look at the 
same sources, we don't reach the same conclusions. You attribute that to 
malice and silly conservatism. The fact of the matter is that the people 
who reach that other conclusion do so based on the fact that they know 
more than you, not less. We know how to program at a low level, we know 
how a CPU works internally, we also know how a GPU works, and we know 
how POV works. Based on all that we have concluded that ATM no general 
GPU library can support POV.
You might be right in that a ray-tracer that has almost the POV syntax 
but does not support the entire set of primitives and textures could be 
implemented now on a GPU. But even if that were the case it would cost a 
lot of manpower that we don't have and the result would almost certainly 
be unusable in a few years time. So we think that it would be a waste of 
our precious time and that we would not like the limitations anyway.

There will come a time when POV will use GPUs, but that time is not now. 
Also remember that the time it takes for a render is seldom the limiting 
factor. If POV gets faster we see opportunities to add just that little 
bit extra to our scenes. Just like starting up a computer takes the same 
order of magnitude of time now as it did 30 years ago. Scrolling a page 
in Word also takes about as much time as it did on a C64. It is all 
about how much time you are willing to spend on it. The reason that I am 
saying that is that apart from just speeding up with Moore's law you can 
increase the performance of POV by introducing a new algorithm or trick. 
There is a surprising number of entries in p.b.i. that are about how to 
achieve an effect.

Another observation: Margareth Thatcher has played a big role in 
achieving that the EU is much less democratic than it should be. Just by 
being stubbornly aggressive on anything that was going on in the EU. 
Nobody wanted to be associated with that sort of single mindedness and 
nobody wanted to let her hold up every discussion forever. The result is 
that there was a lot that could not be discussed openly.
We had a similar thing in this group. I don't know if JPG2000 is an 
improvement over standard JPG, but I know that I never looked seriously 
into that. Nor did I ever try irfanview. And I know why.
My advice: if you want to increase the possibility that one day soon POV 
will be able to use GPUs, just shut up about it. You may point us 
towards new developments, that is what p.o-t is for, but never try to 
tell anybody what he should do.

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