CODEWITHSUNDEEP
openglglslshader
Leon Frickenschmidt
Leon Frickenschmidt

Reputation: 339

OpenGL Compute stage with other stages

I want to have a single shader program that has a Compute stage along with the standard graphics stages (vertex, tess control, tess eval, fragment).

Unfortunately if I attach the Compute stage to the rest of the program and then link it, calls to location queries such as glGetAttribLocation (for uniforms/attributes in any stage) start returning -1, indicating they failed to find the named objects. I also tried using layout(location=N), which resulted in nothing being drawn.

If I attach the stages to two different shader programs and use them one right after the other, both work well (the compute shader writes to a VBO and the draw shader reads from the same VBO), except that I have to switch between them.

Are there limitations on combining Compute stage with the standard graphics stages? All the examples I can find have two programs, but I have not found an explanation for why that would need to be the case.

Upvotes: 4

Views: 354

Answers (1)

Nicol Bolas
Nicol Bolas

Reputation: 473292

OpenGL actively forbids linking a program that contains a compute shader with any non-compute shader types. You should have gotten a linker error when you tried it.

Also, there's really no reason to do so. The only hypothetical benefit you might have gotten from it is having the two sets of shaders sharing uniform values. There just isn't much to gain from having them in the same program.

Upvotes: 6

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