In article <4796cbbb@news.povray.org>, sau### [at] netscapenet says...
> I read once that OpenGL was concieved as a multi-platform 3D manager for
 
> 3D GPUs, regardless the brand of the Video Card, so this could be useful
 
> IMHO, I think also that anyway would be A LOT of effort to write 
> efficient code, to actually make a harmonious coordination with any 
> CPU/GPU combination. Among possible obstacles to solve:
> -Calculate accurately the CPU-GPU latency.
> -Calculate accurately GPU-RAM latency
> -Calculate accurately CPU-RAM latency
> -CPU-GPU coordination latancy.
> 
> I have also read that the GPU is been used as a second powerful math 
> co-processor, so I think POV-Ray should take advantage features like 
> this. Would be great for POV-Ray. It already gave a great jump to 
> paralelism in ver 4 I think we are half way to get to CPU-GPU paralell 
> rendering. Maybe there are some Open Source free-wares already on The 
> Net that could help in a practical way to embed this feature 
> faster/easier, who knows...
> 
> I just love this program, I only want THE BEST tech for it :)
> 
I am going to try to hit the main issues that always come up when this 
idea is presented. I may miss some. However, the two ***key*** issues 
here are:

1. Graphics cards are designed to operate using scanline systems, so 90% 
of what they do is completely useless to POVRay.

2. Even the stuff they could be used for, they can't, because not all 
features use the same floating point sizes, and no card currently 
supports 64-bit floating point. This creates two problems. A) POVRay 
would be limited to using one those floating point processes that "do" 
use the same sizes as it does, for 32-bit systems, and b) for the 90% of 
us who are *probably* at this point running on 64-bit processors, it 
simply won't work at all, since there is no practical way to *fake* 64-
bit operation via such a card, which wouldn't add more overhead than you 
reduce by using the card, and that **assumes** that you could make it 
work at all, since the cards are not designed to do that, and code that 
does do such things uses methods that are not easy to (and may be 
impossible to) adapt to a graphics card.

Put simply, by the time full 64 bit cards come out, some up and coming 
companies might be making POVRay almost entirely redundant anyway, by 
using real raytracing on the card (at least one I know of is trying to 
build one that will do that). So, its not possible now, and it might be 
pointless when it becomes possible. You can be sure however that once it 
does become possible, someone will figure out a way to take advantage of 
it, in the same fashion as its now being redone to support multiple 
cores.

-- 
void main () {

    if version = "Vista" {
      call slow_by_half();
      call DRM_everything();
    }
    call functional_code();
  }
  else
    call crash_windows();
}

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