90889bc73f
Execute GL calls without marshalling them to the context thread. In the cocoa and eagl backends calling gst_gl_context_activate is cheap and therefore calling it on the current thread and serializing GL calls with a per-context lock is more efficient (faster and has less overhead) than marshalling everything to the context thread. This optimization cuts a large overhead in g_poll (continuously waking up the context thread) and in g_mutex_*/g_cond_* (waiting for results from the context thread).