cocoa: don't accidentally drop initial screen drawing

With --idle --force-window, or when started from the bundle, the cocoa
code dropped the first frame. This resulted in a black frame on start
sometimes.

The reason was that the live resizing/redrawing code was invoked, which
simply set skip_swap_buffer to false, blocking redrawing whatever was
going to be rendered next. Normally this is done so that the following
works:

1. vo_opengl draw a frame, releases GL lock
2. live resizing kicks in, redraw the frame
3. vo_opengl wants to call SwapBuffers, drawing a stale buffer
   overwritten by the live resizing code

This is solved by setting skip_swap_buffer in 2., and querying it in 3.

Fix this by resetting the skip_swap_buffer at a known good point: when
vo_opengl starts drawing a new frame.

The start_frame function returns bool, so that it can be merged with
is_active in a following commit.

(cherry picked from commit e23e4c7c603fc1cd911621d0f833031be4a6f7c7)

1 files changed, 6 insertions, 0 deletions

diff --git a/video/out/vo_opengl.c b/video/out/vo_opengl.c
index e409eaa18d..43b2b9e04b 100644
--- a/video/out/vo_opengl.c
+++ b/video/out/vo_opengl.c
@@ -184,6 +184,12 @@ static void draw_image_timed(struct vo *vo, mp_image_t *mpi,
 
     if (mpi)
         gl_video_upload_image(p->renderer, mpi);
+
+    if (p->glctx->start_frame && !p->glctx->start_frame(p->glctx)) {
+        mpgl_unlock(p->glctx);
+        return;
+    }
+
     gl_video_render_frame(p->renderer, 0, t);
 
     // The playloop calls this last before waiting some time until it decides