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.

1 files changed, 9 insertions, 1 deletions

diff --git a/video/out/cocoa_common.m b/video/out/cocoa_common.m
index e768e06e7d..8a0473e729 100644
--- a/video/out/cocoa_common.m
+++ b/video/out/cocoa_common.m
@@ -632,13 +632,21 @@ static void draw_changes_after_next_frame(struct vo *vo)
     }
 }
 
+bool vo_cocoa_start_frame(struct vo *vo)
+{
+    struct vo_cocoa_state *s = vo->cocoa;
+
+    s->skip_swap_buffer = false;
+    return true;
+}
+
 void vo_cocoa_swap_buffers(struct vo *vo)
 {
     struct vo_cocoa_state *s = vo->cocoa;
 
     if (s->skip_swap_buffer && !s->waiting_frame) {
         s->skip_swap_buffer = false;
-        return;
+        s->pending_events |= VO_EVENT_EXPOSE;
     } else {
         [s->gl_ctx flushBuffer];
     }