it seems, that glClientWaitSync always finish the gl pipeline although the fence is already fired. I tried it in this way:
GLsync sync = glFenceSync(GL_SYNC_GPU_COMMANDS_COMPLETE, 0);
glFinish(); // be sure, sync is fired
glClientWaitSync(sync, GL_SYNC_FLUSH_COMMANDS_BIT, 0); // return GL_ALREADY_SIGNALED
I think, the glClientWaitSync call must not block, but nsight shows that it finish the pipeline.
What may I do wrong here? Or may it be a driver issue?
Windows 8 x64
GeForce GTX 660 Ti