Hi, I am investigating what kind of Wayland protocol extensions would be needed to support proper presentation timing. Looking at existing works, I am wondering about two things whether they have any real use.
Where is swap interval (e.g. eglSwapInterval) greater than one useful? Intervals 0 and 1 I understand, and Mesa EGL Wayland already supports those. But when would you like to make your framerate a fraction of the display's? When are the target-MSC related remainder and divisor parameters as defined in the GLX_OML_sync_control useful? Why does also X11 Present protocol include remainder and divisor? GLX_OML_sync_control defines that for interlaced displays MSC is incremented for each field. With divisor and remainder you could then target only top or bottom fields. Is that useful, and do we care about interlaced displays anymore? I am contemplating on not supporting these, because I am going to propose using an UST-like clock as the "standard clock language" in Wayland present extension. Supporting MSC-based timings would add complexity. Therefore I would like to know where and how the above mentioned are useful, because I cannot imagine it myself. Please, let me know of real actual use cases and existing software, where these features offer a visible benefit and what that benefit is exactly. I am not interested in what one might do in theory, I am interested in real-world examples where they have proved useful. Well, maybe also theories if they allow taking advantage of some new cool technology. Btw. if you think that using UST for presentation timing and feedback is nonsense, and MSC is the only right way, let me know and I can start another email thread about that detail after preparing my material. Thanks, pq _______________________________________________ mesa-dev mailing list mesa-dev@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/mesa-dev
