/**
* gst_gl_query_local_gl_context:
* @element: a #GstElement to query from
* @direction: the #GstPadDirection to query
* @context_ptr: (inout): location containing the current and/or resulting
* #GstGLContext
*
* Performs a GST_QUERY_CONTEXT query of type "gst.gl.local_context" on all
* #GstPads in @element of @direction for the local OpenGL context used by
* GStreamer elements.
*
* Returns: whether @context_ptr contains a #GstGLContext
*/
gboolean
gst_gl_query_local_gl_context (GstElement * element, GstPadDirection direction,
GstGLContext ** context_ptr)
{
GstQuery *query;
GstContext *context;
const GstStructure *s;
g_return_val_if_fail (GST_IS_ELEMENT (element), FALSE);
g_return_val_if_fail (context_ptr != NULL, FALSE);
if (*context_ptr)
return TRUE;
query = gst_query_new_context ("gst.gl.local_context");
if (gst_gl_run_query (GST_ELEMENT (element), query, direction)) {
gst_query_parse_context (query, &context);
if (context) {
s = gst_context_get_structure (context);
gst_structure_get (s, "context", GST_TYPE_GL_CONTEXT, context_ptr, NULL);
}
}
gst_query_unref (query);
return *context_ptr != NULL;
}
static void
_gst_context_query (GstElement * element, const gchar * display_type)
{
GstQuery *query;
GstContext *ctxt;
_init_context_debug ();
/* 2a) Query downstream with GST_QUERY_CONTEXT for the context and
* check if downstream already has a context of the specific type
* 2b) Query upstream as above.
*/
query = gst_query_new_context (display_type);
if (gst_gl_run_query (element, query, GST_PAD_SRC)) {
gst_query_parse_context (query, &ctxt);
GST_CAT_INFO_OBJECT (GST_CAT_CONTEXT, element,
"found context (%p) in downstream query", ctxt);
gst_element_set_context (element, ctxt);
} else if (gst_gl_run_query (element, query, GST_PAD_SINK)) {
gst_query_parse_context (query, &ctxt);
GST_CAT_INFO_OBJECT (GST_CAT_CONTEXT, element,
"found context (%p) in upstream query", ctxt);
gst_element_set_context (element, ctxt);
} else {
/* 3) Post a GST_MESSAGE_NEED_CONTEXT message on the bus with
* the required context type and afterwards check if a
* usable context was set now as in 1). The message could
* be handled by the parent bins of the element and the
* application.
*/
GstMessage *msg;
GST_CAT_INFO_OBJECT (GST_CAT_CONTEXT, element,
"posting need context message");
msg = gst_message_new_need_context (GST_OBJECT_CAST (element),
display_type);
gst_element_post_message (element, msg);
}
/*
* Whomever responds to the need-context message performs a
* GstElement::set_context() with the required context in which the element
* is required to update the display_ptr or call gst_gl_handle_set_context().
*/
gst_query_unref (query);
}
static gboolean
_find_local_gl_context (GstGLStereoSplit * split)
{
GstQuery *query;
GstContext *context;
const GstStructure *s;
if (split->context)
return TRUE;
query = gst_query_new_context ("gst.gl.local_context");
if (!split->context
&& gst_gl_run_query (GST_ELEMENT (split), query, GST_PAD_SRC)) {
gst_query_parse_context (query, &context);
if (context) {
s = gst_context_get_structure (context);
gst_structure_get (s, "context", GST_GL_TYPE_CONTEXT, &split->context,
NULL);
}
}
if (!split->context
&& gst_gl_run_query (GST_ELEMENT (split), query, GST_PAD_SINK)) {
gst_query_parse_context (query, &context);
if (context) {
s = gst_context_get_structure (context);
gst_structure_get (s, "context", GST_GL_TYPE_CONTEXT, &split->context,
NULL);
}
}
GST_DEBUG_OBJECT (split, "found local context %p", split->context);
gst_query_unref (query);
if (split->context)
return TRUE;
return FALSE;
}
