25b388c43b
it turns out that we cannot return INVALID_OPERATION from glGetError() because the GL spec says that it must be called in a loop until it returns GL_NO_ERROR. now, we always return 0 from GL functions called from a thread with no context bound. This means that glGetError() will return NO_ERROR in this case, which is better than returning a random value (which could trap the app in a loop). if this happens in the main thread of a process, we LOG an error message once. Change-Id: Id59620e675a890286ef62a257c02b06e0fdcaf69