"Empty" rendering with openGL

2
votes

specs: Radeon 3870HD w/ openGL 3.3 & GLSL 1.5

I am rendering data through computational shader. Because of dependencies I had to put all my data to uniform textures and nothing left for attributes. Only value that change per primitve is index and I can get this one from gl_VertexID. But I'm having problem with setting up proper render call, looks like if there are no attribute pointers set the render doesn't even run, setting pointer but not storage results in error(ofc..). Setting storage isn't empty rendering ;). Is there any way to render this setup?

Yeah and I forgot some important things.. I render with:

glDrawArrays(GL_POINTS, 0, elements);

and the reason I think it doesn't run shader is because query on processed primitives results 0.. Setting some dummy attribute pointer with data results in right number of primitives...

1
c++openglglslgpgpu
have you tries rendering simple triangle? – fazo
uhm how do you imagine that? If you meant that setting render calls to GL_TRIANGLES I tried that right now but it doesn't work also.. – Raven

1 Answers

0
votes

I had the same issue with ATI. In order to bypass it I'm using any accessible buffer for a dummy 1-byte per vertex input array (not used by the shader).