Levels of support in hardware/drivers?

[Richard Jones]

I've searched and searched, but I cannot find anything on the web that details the level of GLSL support across various hardware and drivers.

In particular, I'm interested in the bugs that are known to exist.

For example, I recently tried to implement a simple nested loop on my Mac powerbook and after a certain number of nested iterations it just stopped working.

I know of a single vendor-supplied document from nvidia which details some limitations of their G30 and G40 hardware (ie. noise() always returns 0s and some other restrictions).

Is there anything more comprehensive?

[Korval]

I recently tried to implement a simple nested loopNo loops are simple in shaders. Ever.

[Jan]

Vendors are usually not very good at pointing out the limits of their hardware. Especially, if those are not obvious.

I don't know of any such documents. As a rule of thumb, anything, that is not absolutely trivial, will make problems on some hardware with some drivers.

Jan.

[Brolingstanz]

Feature-wise, http://www.delphi3d.net/ is a great place to see various cards and their capabilities. Check out the 3D hardware info link.

[km,]

I think on Nvidia cards there is a limit for a single loop to 255. I think it is documented somewhere, else can see in the forum at gpgpu.org.

Is this what limitation you are seeing regarding for loops?

Ketan

p.s Nvidia has a note on their site giving limitations and extra features under GLSL - like shader pre-linking or use of half.