caopengllayersink: render black when we don't have a texture to display

Like when the winsys asks us to redraw before the pipeline has started

diff --git a/ext/gl/caopengllayersink.m b/ext/gl/caopengllayersink.m
index 1f7b3d1eb35f41f3d21716daa10b86099e1ed6b8..fdbcf7bba9e1cb480ac50d4f09cc84879878d7f0 100644 (file)
--- a/ext/gl/caopengllayersink.m
+++ b/ext/gl/caopengllayersink.m
@@ -983,6 +983,8 @@ gst_ca_opengl_layer_sink_on_draw (GstCAOpenGLLayerSink * ca_sink)
 
   /* check if texture is ready for being drawn */
   if (!ca_sink->redisplay_texture) {
+    gl->ClearColor (0.0f, 0.0f, 0.0f, 1.0f);
+    gl->Clear (GL_COLOR_BUFFER_BIT);
     GST_CA_OPENGL_LAYER_SINK_UNLOCK (ca_sink);
     return;
   }