GL_MAX_PROGRAM_EXEC_INSTRUCTIONS_NV limitation "per pixel" or "per frame" ?

Hello,

I have a little question about GL_MAX_PROGRAM_EXEC_INSTRUCTIONS_NV.

On my NVIDIA GTX 7900 it returns: 4530371

Does this mean each fragment can execute 4.5 million instructions before
being terminated ?

Or does this mean all fragments together can execute at most 4.5 millions
instructions before being terminated ?

So is this limitation "per pixel" or "per frame" ???

Bye,
Skybuck.

Hmm to answer my own question... I guess it's per pixel...

Since a frame can be 1920x1200 pixels... which would be: 2304000

So if it were 4.5 million in total.. then that would only be roughly 2
instructions per pixel which would be pretty crappy

So I think it's 4.5 million per pixel !

Bye,
Skybuck.

Skybuck Flying wrote:

> Hello,
>
> I have a little question about GL_MAX_PROGRAM_EXEC_INSTRUCTIONS_NV.
>
> On my NVIDIA GTX 7900 it returns: 4530371
>
> Does this mean each fragment can execute 4.5 million instructions before
> being terminated?

I think the terminology "instruction count" is quite clear: It limits the
length of your program. From your point of view the GPU is a massive
parallel processor, that executes the same program on a very large data
file (the textures and the framebuffer).

> So is this limitation "per pixel" or "per frame" ???

Think about the following: Early generations of shader capable GPUs had an
instruction limit of ~200. I think this should make the answer obvious.


Wolfgang
--
OpenGL tip #42:
How to exactly map texture texels to screen pixels:
<http://preview.tinyurl.com/cgndc8>