video/out: always support redrawing VO window at any point

Before, a VO could easily refuse to respond to VOCTRL_REDRAW_FRAME,
which means the VO wouldn't redraw OSD and window contents, and the
player would appear frozen to the user. This was a bit stupid, and makes
dealing with some corner cases much harder (think of --keep-open, which
was hard to implement, because the VO gets into this state if there are
no new video frames after a seek reset).

Change this, and require VOs to always react to VOCTRL_REDRAW_FRAME.
There are two aspects of this: First, behavior after a (successful)
vo_reconfig() call, but before any video frame has been displayed.
Second, behavior after a vo_seek_reset().

For the first issue, we define that sending VOCTRL_REDRAW_FRAME after
vo_reconfig() should clear the window with black. This requires minor
changes to some VOs. In particular vaapi makes this horribly
complicated, because OSD rendering is bound to a video surface. We
create a black dummy surface for this purpose.

The second issue is much simpler and works already with most VOs: they
simply redraw whatever has been uploaded previously. The exception is
vdpau, which has a complicated mechanism to track and filter video
frames. The state associated with this mechanism is completely cleared
with vo_seek_reset(), so implementing this to work as expected is not
trivial. For now, we just clear the window with black.

1 files changed, 12 insertions, 0 deletions

diff --git a/video/out/vo_direct3d.c b/video/out/vo_direct3d.c
index e265b0b38f..f16ac87703 100644
--- a/video/out/vo_direct3d.c
+++ b/video/out/vo_direct3d.c
@@ -130,6 +130,8 @@ typedef struct d3d_priv {
 
     struct vo *vo;
 
+    bool have_image;
+
     D3DLOCKED_RECT locked_rect; /**< The locked offscreen surface */
     RECT fs_movie_rect;         /**< Rect (upscaled) of the movie when displayed
                                 in fullscreen */
@@ -842,6 +844,9 @@ static uint32_t d3d_draw_frame(d3d_priv *priv)
 
     IDirect3DDevice9_Clear(priv->d3d_device, 0, NULL, D3DCLEAR_TARGET, 0, 0, 0);
 
+    if (!priv->have_image)
+        return VO_TRUE;
+
     if (priv->use_textures) {
 
         for (n = 0; n < priv->plane_count; n++) {
@@ -1271,6 +1276,8 @@ static int config(struct vo *vo, uint32_t width, uint32_t height,
 {
     d3d_priv *priv = vo->priv;
 
+    priv->have_image = false;
+
     /* w32_common framework call. Creates window on the screen with
      * the given coordinates.
      */
@@ -1412,6 +1419,8 @@ static void draw_image(struct vo *vo, mp_image_t *mpi)
         }
     }
 
+    priv->have_image = true;
+
     d3d_draw_frame(priv);
 }
 
@@ -1420,6 +1429,9 @@ static mp_image_t *get_screenshot(d3d_priv *priv)
     if (!priv->d3d_device)
         return NULL;
 
+    if (!priv->have_image)
+        return NULL;
+
     struct mp_image buffer;
     if (!get_video_buffer(priv, &buffer))
         return NULL;