Framebuffer blits depends on pixel tests:
Ownership (is fine)
Scissor (is broken on the last commit)
Masking (is broken on master for a while)
So let's be honest and start with a clean state in
those helper functions.
There is no need to disable this state after the draw call,
gl_state will handle this for us if needed. This kind of
redundant state changes are bad for the driver overhead,
as flipping bits will invalidate the driver state.
This replaces the glBufferData logic with the shared stream buffer code.
The new code doesn't need a temporary staging buffer any more, so the
performance should imrpove quite a bit.
This OpenGL call synchronize the worker thread of the nvidia blob.
It can be verified on linux with the __GL_THREADED_OPTIMIZATIONS=1 environment variable.
Those errors should not happen on tested drivers.
It was used as a workaround for https://bugs.freedesktop.org/show_bug.cgi?id=94148
Markus Wick