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digitalmars.D.announce - Re: GPUFractal-1

Nathan Reed Wrote:

 Burton Radons wrote:
 Bill Baxter Wrote:
 Bruno Medeiros wrote:
 Jascha Wetzel wrote:
 Vendor: 'NVIDIA Corporation'
 Renderer: 'GeForce 7600 GS/PCI/SSE2'
 Version: '2.0.3'
 Error: Could not successfully link program: Fragment info
 (69) : error C5051: profile does not support conditional returns

Yuppers, the current driver version is 2.1.1. I've put a check in that'll very bluntly detect this by assuming that more recent drivers support more recent GLSL versions. This part actually won't change with Cg because if the GLSL part of the driver can't handle branching, then it surely won't support the newer fragment/vertex program profiles which can handle it either.

Actually. Historically, I have heard (and experienced) that ATI's driver support for GLSL is very poor. It may not be that the GPU can't handle branching but that ATI's GLSL compiler can't. Cg may actually work much better because it involves a compiler separate from the driver that can translate the code into ARB assembly (with extensions for branching and so forth) and feed it to the card.

Theory busted. I'm on the X850 right now with the latest driver version. The only profile pairs Cg says is supported here are the five-year-old arbfp1/arbvp1 and GLSL. It acts the same way as in GLSL, requiring a non-branching, very limited loop.
Oct 20 2007