WGL_I3D_swap_frame_usage http://www.opengl.org/registry/specs/gl/I3D/wgl_swap_frame_usage.txt WGL_I3D_swap_frame_usage BOOL wglBeginFrameTrackingI3D (void) BOOL wglEndFrameTrackingI3D (void) BOOL wglGetFrameUsageI3D (float* pUsage) BOOL wglQueryFrameTrackingI3D (DWORD* pFrameCount, DWORD *pMissedFrames, float *pLastMissedUsage)