vo_opengl_cb: initial screenshot support

Support for taking screenshots when doing hardware decoding needs to be
added later.

This takes the last image queued to the VO, which is logically the image
the player thinks is on screen (so e.g. subtitles will match).

forget_frames() does not clear this, because seeking does not remove the
current image from the screen (until the next one is drawn).

1 files changed, 10 insertions, 0 deletions

diff --git a/video/out/vo_opengl_cb.c b/video/out/vo_opengl_cb.c
index 6c7916d7f1..4a0ba3dc54 100644
--- a/video/out/vo_opengl_cb.c
+++ b/video/out/vo_opengl_cb.c
@@ -65,6 +65,7 @@ struct mpv_opengl_cb_context {
     mpv_opengl_cb_update_fn update_cb;
     void *update_cb_ctx;
     struct mp_image *waiting_frame;
+    struct mp_image *displayed_frame;
     struct mp_image **frame_queue;
     int queued_frames;
     struct mp_image_params img_params;
@@ -357,6 +358,7 @@ static void draw_image(struct vo *vo, mp_image_t *mpi)
 
     pthread_mutex_lock(&p->ctx->lock);
     mp_image_setrefp(&p->ctx->waiting_frame, mpi);
+    mp_image_setrefp(&p->ctx->displayed_frame, mpi);
     talloc_free(mpi);
     pthread_mutex_unlock(&p->ctx->lock);
 }
@@ -486,6 +488,13 @@ static int control(struct vo *vo, uint32_t request, void *data)
         update(p);
         pthread_mutex_unlock(&p->ctx->lock);
         return VO_TRUE;
+    case VOCTRL_SCREENSHOT: {
+        struct voctrl_screenshot_args *args = data;
+        pthread_mutex_lock(&p->ctx->lock);
+        args->out_image = mp_image_new_ref(p->ctx->displayed_frame);
+        pthread_mutex_unlock(&p->ctx->lock);
+        return VO_TRUE;
+    }
     case VOCTRL_SET_COMMAND_LINE: {
         char *arg = data;
         return reparse_cmdline(p, arg);
@@ -506,6 +515,7 @@ static void uninit(struct vo *vo)
 
     pthread_mutex_lock(&p->ctx->lock);
     forget_frames(p->ctx);
+    mp_image_unrefp(&p->ctx->displayed_frame);
     p->ctx->img_params = (struct mp_image_params){0};
     p->ctx->reconfigured = true;
     p->ctx->active = NULL;