Hi,

I'm trying to work with some shaders on my macbook pro. I downloaded the toolkit, included the framework in my xcode project, and wrote:

...
CGcontext cgContext;
...
cgContext = cgCreateContext();
...


however, cgContext is NULL and the application ends ...
Any idea why this isnt working?

Thanks

I don't think ATI graphics cards support cg directly. (since it is a NVidia language) You will need to compile the shaders into assembly, then use the corresponding functions for assembly shaders.

akb825 Wrote:I don't think ATI graphics cards support cg directly. (since it is a NVidia language) You will need to compile the shaders into assembly, then use the corresponding functions for assembly shaders.

That's not actually true, I have been using Cg on my G4 Powerbook (Mobility Radeon 9600) since I got it a few years ago. You are restricted to using the ARB profiles but other than that it should generally work ok.

Saying that though, I am now moving to GLSL which integrates much better with OpenGL. If you know one, switching to the other is trivial.

icklefrelp Wrote:That's not actually true, I have been using Cg on my G4 Powerbook (Mobility Radeon 9600) since I got it a few years ago. You are restricted to using the ARB profiles but other than that it should generally work ok.

Saying that though, I am now moving to GLSL which integrates much better with OpenGL. If you know one, switching to the other is trivial.

do you use GLEW ?
and one more thing: whats this AGL and GLX things? there are downloads of glew binaries for both, which one should i choose?

habahaba Wrote:do you use GLEW ?
and one more thing: whats this AGL and GLX things? there are downloads of glew binaries for both, which one should i choose?

I don't use GLEW although I should probably look into it, currently I don't check for supported extensions as I know the extensions I'm using are supported on my machines.

I assume you want the AGL version, I'm guessing the GLX version is for OpenGl on X11.

Cg should work fine, but doesn't give you access to the full power of any modern ATI hardware (including the X1600 in yourMBP). It's also not a technology many people use on the Mac. I'd highly recommend using GLSL.