From 2b6241a09a136db26834e75aeb3730f00894ee54 Mon Sep 17 00:00:00 2001 From: wm4 Date: Fri, 30 Oct 2015 20:26:51 +0100 Subject: vo_opengl: add vsync-fences option Yet another relatively useless option that tries to make OpenGL's sync behavior somewhat sane. The results are not too encouraging. With a value of 1, vsync jitter is gone on nVidia, but there are frame drops (less than with glfinish). With 2, I get the usual vsync jitter _and_ frame drops. There's still some hope that it might prevent too deep queuing with some GPUs, I guess. The timeout for the wait call is 1 second. The value is pretty arbitrary; it should just not be too high to freeze the process (if the GPU is un-nice), and not too low to trigger the timeout in normal cases, even if the GPU load is very high. So I guess 1 second is ok as a timeout. The idea to use fences this way to control the queue depth was stolen from RetroArch: https://github.com/libretro/RetroArch/blob/df01279cf318e7ec90ace039d60515296e3de908/gfx/drivers/gl.c#L1856 --- DOCS/man/vo.rst | 9 +++++++++ 1 file changed, 9 insertions(+) (limited to 'DOCS') diff --git a/DOCS/man/vo.rst b/DOCS/man/vo.rst index 7b6358be6e..2cebd153ff 100644 --- a/DOCS/man/vo.rst +++ b/DOCS/man/vo.rst @@ -667,6 +667,15 @@ Available video output drivers are: X11/GLX only. + ``vsync-fences=`` + Synchronize the CPU to the Nth past frame using the ``GL_ARB_sync`` + extension. A value of 0 disables this behavior (default). A value of + 1 means it will synchronize to the current frame after rendering it. + Like ``glfinish`` and ``waitvsync``, this can lower or ruin performance. + Its advantage is that it can span multiple frames, and effectively limit + the number of frames the GPU queues ahead (which also has an influence + on vsync). + ``dwmflush=`` Calls ``DwmFlush`` after swapping buffers on Windows (default: no). It also sets ``SwapInterval(0)`` to ignore the OpenGL timing. Values -- cgit v1.2.3