PixarAnimationStudios
Fix issues using Hydra and Storm with OpenGL core profile
Description of Change(s)
These changes together make Hydra and Storm work without warnings in Blender, which uses the OpenGL core profile rather than the compatibility profile.
- Don't use point size or line width for core profile, since these are not available and generate many warnings. This only silences the warnings, ideally these features would be implemented in shaders.
- Fix missing VAO binding that is required with the core profile, causing Storm renders to fail.
- Also fix VAO double free and leak in GL graphics pipeline that I noticed looking into this.
The solution for VAOs in HdSt_IndirectDrawBatch does not seem ideal, as OpenGL usage should be abstracted away in hgiGL. However OpenGL vertex buffer binding still seems to be part of hdSt and it's not clear to me where it will move exactly.
Also note that while it may seem that in HdSt_IndirectDrawBatch::_ExecuteFrustumCull, cullGfxCmds->BindPipeline will bind the VAO, this doesn't actually work because those commands are queued and only executed after functions like state.BindResourcesForViewTransformation that bind the vertex buffer objects.
Advice for a better solution would be welcome.
- [x] I have verified that all unit tests pass with the proposed changes
- [x] I have submitted a signed Contributor License Agreement
