Two ways of Gl based rotation are imaginable:
- Do it in the Scene via model-view-projection (MVP) matrix and adapt all effects interacting with the MVP as well. This is the approach in D19860. The issue is of course with our current effects system that all current and future effects have to respect what is an implementation detail dependent on the backend.
- Do it in a post-processing step after Scene rendering has finished. For that render in a separate framebuffer and sample the rotated texture to the screen framebuffer.
Patch is WIP.See D25907.