• Burton Radons <burton-radons shaw.ca> Oct 20 2007

Burton Radons <burton-radons shaw.ca> writes:

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.