Christoph Hormann <chr### [at] gmxde> wrote:
> >   And my questiom is: When it supports 64-bit floating point numbers,
> > how will it be different from current FPUs?

> The most important difference probably is that the GPUs are closed 
> products with no comprehensive specifications being available.  If you 
> like to use them you have to use the proprietary SDKs provided by Nvidia 
> and available only for the platforms they support (if you are lucky they 
> offer a x86-linux version - usually working only in combination with 
> their closed hardware drivers, if not it's Windows only).

  I'm also wondering about what advantages there could be compared to
current FPUs.

  There are obvious advantages to the graphics which the graphics card
itself renders. Currently vertex and pixel shaders have no or very little
floating point math support, and adding that support will probably allow
more stunning graphics effects to be achieved.

  However, how could POV-Ray benefit from this? What will this offer for
POV-Ray that current FPUs don't?

  Besides, there will probably be data transfer overhead. Games can simply
upload their vertex and pixel shader code into the graphics card and then
let the graphics card do what they do. Games don't need the results back.

  POV-Ray does need the results of the calculations back. How is it going
to do that? And what advantages will this bring to it compared to the
current regular usage of the FPU (which has in practice no overhead)?

  Sure, some graphics software are using modern graphics cards to perform
eg. image transformations and filters. But that's a much simpler task.
The software simply uploads a shader to the graphics card, tells it to
apply it to a texture, and the graphics card does that. It's a simple task
which the graphics card can do all by itself. When it's done, the software
can simply read the resulting image.
  This is a bit different from what POV-Ray does. POV-Ray can't work by
simply applying a shader to an image. POV-Ray is a raytracer.

-- 
                                                          - Warp

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