qmlglsink: check qt_context_ first in GstQSGTexture::bind()

When start qmlglsink app, it will set NULL buffer to GstQSGTexture
in which case that qt_context_ will be a random value and cause
gst_gl_context_activate() fail.

https://bugzilla.gnome.org/show_bug.cgi?id=770925

diff --git a/ext/qt/gstqsgtexture.cc b/ext/qt/gstqsgtexture.cc
index 13208c0..85747f2 100644 (file)
--- a/ext/qt/gstqsgtexture.cc
+++ b/ext/qt/gstqsgtexture.cc
@@ -45,6 +45,7 @@ GstQSGTexture::GstQSGTexture ()
 
   gst_video_info_init (&this->v_info);
   this->buffer_ = NULL;
+  this->qt_context_ = NULL;
   this->sync_buffer_ = gst_buffer_new ();
 }
 
@@ -87,6 +88,9 @@ GstQSGTexture::bind ()
   GstMemory *mem;
   guint tex_id;
 
+  if (!this->qt_context_)
+    return;
+
   gst_gl_context_activate (this->qt_context_, TRUE);
 
   if (!this->buffer_)