opengl: win32 - add option 'dwmflush' to sync in DWM

This could help in cases where the DWM (Windows desktop compositor) adds another
layer of bufferring and therefore the SwapBuffers timing could get messed up.

Signed-off-by: wm4 <wm4@nowhere>

1 files changed, 11 insertions, 0 deletions

diff --git a/video/out/vo_opengl.c b/video/out/vo_opengl.c
index 589ae7b0db..fb47464e9a 100644
--- a/video/out/vo_opengl.c
+++ b/video/out/vo_opengl.c
@@ -72,6 +72,9 @@ struct gl_priv {
     int use_gl_debug;
     int allow_sw;
     int swap_interval;
+    int current_swap_interval;
+    int dwm_flush;
+
     char *backend;
 
     int vo_flipped;
@@ -154,6 +157,12 @@ static void flip_page(struct vo *vo)
         }
     }
 
+    if (p->glctx->DwmFlush) {
+        p->current_swap_interval = p->glctx->DwmFlush(p->glctx, p->dwm_flush,
+                                                      p->swap_interval,
+                                                      p->current_swap_interval);
+    }
+
     mpgl_unlock(p->glctx);
 }
 
@@ -463,6 +472,7 @@ static int preinit(struct vo *vo)
     } else {
         MP_VERBOSE(vo, "swap_control extension missing.\n");
     }
+    p->current_swap_interval = p->swap_interval;
 
     p->renderer = gl_video_init(p->gl, vo->log);
     if (!p->renderer)
@@ -498,6 +508,7 @@ static const struct m_option options[] = {
     OPT_FLAG("glfinish", use_glFinish, 0),
     OPT_FLAG("waitvsync", waitvsync, 0),
     OPT_INT("swapinterval", swap_interval, 0, OPTDEF_INT(1)),
+    OPT_INT("dwmflush", dwm_flush, 0, OPTDEF_INT(0)),
     OPT_FLAG("debug", use_gl_debug, 0),
     OPT_STRING_VALIDATE("backend", backend, 0, mpgl_validate_backend_opt),
     OPT_FLAG("sw", allow_sw, 0),