From 56d9fb13f93abbf5aa5af81e39ae73642016fe95 Mon Sep 17 00:00:00 2001
From: Matthew Waters <matthew@centricular.com>
Date: Wed, 5 Feb 2020 12:26:54 +1100
Subject: [PATCH] glbasefilter: add support for changing the display

Each element will remove its usage of the old display and context and
try to retrieve a new GL context.
---
 ext/gl/gstglcolorconvertelement.c |  44 ++++---
 gst-libs/gst/gl/gstglbasefilter.c | 195 ++++++++++++++++++++++--------
 gst-libs/gst/gl/gstglbasefilter.h |   4 +
 tests/check/elements/glfilter.c   | 131 ++++++++++++++++++++
 tests/check/meson.build           |   1 +
 5 files changed, 310 insertions(+), 65 deletions(-)
 create mode 100644 tests/check/elements/glfilter.c

diff --git a/ext/gl/gstglcolorconvertelement.c b/ext/gl/gstglcolorconvertelement.c
index 25e7daab9..256e5ef5a 100644
--- a/ext/gl/gstglcolorconvertelement.c
+++ b/ext/gl/gstglcolorconvertelement.c
@@ -36,15 +36,14 @@ G_DEFINE_TYPE_WITH_CODE (GstGLColorConvertElement, gst_gl_color_convert_element,
         "glconvertelement", 0, "convert");
     );
 
-static gboolean gst_gl_color_convert_element_set_caps (GstBaseTransform * bt,
-    GstCaps * in_caps, GstCaps * out_caps);
+static gboolean gst_gl_color_convert_element_gl_set_caps (GstGLBaseFilter *
+    base_filter, GstCaps * in_caps, GstCaps * out_caps);
 static GstCaps *gst_gl_color_convert_element_transform_caps (GstBaseTransform *
     bt, GstPadDirection direction, GstCaps * caps, GstCaps * filter);
 static gboolean gst_gl_color_convert_element_get_unit_size (GstBaseTransform *
     trans, GstCaps * caps, gsize * size);
-static gboolean
-gst_gl_color_convert_element_filter_meta (GstBaseTransform * trans,
-    GstQuery * query, GType api, const GstStructure * params);
+static gboolean gst_gl_color_convert_element_filter_meta (GstBaseTransform *
+    trans, GstQuery * query, GType api, const GstStructure * params);
 static gboolean gst_gl_color_convert_element_decide_allocation (GstBaseTransform
     * trans, GstQuery * query);
 static GstFlowReturn
@@ -52,8 +51,8 @@ gst_gl_color_convert_element_prepare_output_buffer (GstBaseTransform * bt,
     GstBuffer * inbuf, GstBuffer ** outbuf);
 static GstFlowReturn gst_gl_color_convert_element_transform (GstBaseTransform *
     bt, GstBuffer * inbuf, GstBuffer * outbuf);
-static GstCaps *gst_gl_color_convert_element_fixate_caps (GstBaseTransform *
-    bt, GstPadDirection direction, GstCaps * caps, GstCaps * othercaps);
+static GstCaps *gst_gl_color_convert_element_fixate_caps (GstBaseTransform * bt,
+    GstPadDirection direction, GstCaps * caps, GstCaps * othercaps);
 static GstStateChangeReturn
 gst_gl_color_convert_element_change_state (GstElement * element,
     GstStateChange transition);
@@ -70,34 +69,33 @@ GST_STATIC_PAD_TEMPLATE ("sink",
     GST_PAD_ALWAYS,
     GST_STATIC_CAPS (GST_GL_COLOR_CONVERT_VIDEO_CAPS));
 
-static gboolean
-gst_gl_color_convert_element_stop (GstBaseTransform * bt)
+static void
+gst_gl_color_convert_element_gl_stop (GstGLBaseFilter * filter)
 {
-  GstGLColorConvertElement *convert = GST_GL_COLOR_CONVERT_ELEMENT (bt);
+  GstGLColorConvertElement *convert = GST_GL_COLOR_CONVERT_ELEMENT (filter);
 
   if (convert->convert) {
     gst_object_unref (convert->convert);
     convert->convert = NULL;
   }
 
-  return GST_BASE_TRANSFORM_CLASS (parent_class)->stop (bt);
+  GST_GL_BASE_FILTER_CLASS (parent_class)->gl_stop (filter);
 }
 
 static void
 gst_gl_color_convert_element_class_init (GstGLColorConvertElementClass * klass)
 {
+  GstGLBaseFilterClass *filter_class = GST_GL_BASE_FILTER_CLASS (klass);
   GstBaseTransformClass *bt_class = GST_BASE_TRANSFORM_CLASS (klass);
   GstElementClass *element_class = GST_ELEMENT_CLASS (klass);
 
   bt_class->transform_caps = gst_gl_color_convert_element_transform_caps;
-  bt_class->set_caps = gst_gl_color_convert_element_set_caps;
   bt_class->get_unit_size = gst_gl_color_convert_element_get_unit_size;
   bt_class->filter_meta = gst_gl_color_convert_element_filter_meta;
   bt_class->decide_allocation = gst_gl_color_convert_element_decide_allocation;
   bt_class->prepare_output_buffer =
       gst_gl_color_convert_element_prepare_output_buffer;
   bt_class->transform = gst_gl_color_convert_element_transform;
-  bt_class->stop = gst_gl_color_convert_element_stop;
   bt_class->fixate_caps = gst_gl_color_convert_element_fixate_caps;
 
   bt_class->passthrough_on_same_caps = TRUE;
@@ -113,6 +111,9 @@ gst_gl_color_convert_element_class_init (GstGLColorConvertElementClass * klass)
       "OpenGL color converter", "Filter/Converter/Video",
       "Converts between color spaces using OpenGL shaders",
       "Matthew Waters <matthew@centricular.com>");
+
+  filter_class->gl_stop = gst_gl_color_convert_element_gl_stop;
+  filter_class->gl_set_caps = gst_gl_color_convert_element_gl_set_caps;
 }
 
 static void
@@ -123,10 +124,14 @@ gst_gl_color_convert_element_init (GstGLColorConvertElement * convert)
 }
 
 static gboolean
-gst_gl_color_convert_element_set_caps (GstBaseTransform * bt,
+gst_gl_color_convert_element_gl_set_caps (GstGLBaseFilter * base_filter,
     GstCaps * in_caps, GstCaps * out_caps)
 {
-  GstGLColorConvertElement *convert = GST_GL_COLOR_CONVERT_ELEMENT (bt);
+  GstGLColorConvertElement *convert =
+      GST_GL_COLOR_CONVERT_ELEMENT (base_filter);
+
+  if (!convert->convert && base_filter->context)
+    convert->convert = gst_gl_color_convert_new (base_filter->context);
 
   if (!gst_gl_color_convert_set_caps (convert->convert, in_caps, out_caps))
     return FALSE;
@@ -141,16 +146,21 @@ gst_gl_color_convert_element_transform_caps (GstBaseTransform * bt,
   GstGLColorConvertElement *convert = GST_GL_COLOR_CONVERT_ELEMENT (bt);
   GstGLBaseFilter *base_filter = GST_GL_BASE_FILTER (bt);
   GstGLContext *context;
+  GstCaps *ret;
 
   if (base_filter->display && !gst_gl_base_filter_find_gl_context (base_filter))
     return NULL;
 
-  context = GST_GL_BASE_FILTER (bt)->context;
+  context = gst_gl_base_filter_get_gl_context (base_filter);
 
   if (!convert->convert && context)
     convert->convert = gst_gl_color_convert_new (context);
 
-  return gst_gl_color_convert_transform_caps (context, direction, caps, filter);
+  ret = gst_gl_color_convert_transform_caps (context, direction, caps, filter);
+
+  gst_clear_object (&context);
+
+  return ret;
 }
 
 static gboolean
diff --git a/gst-libs/gst/gl/gstglbasefilter.c b/gst-libs/gst/gl/gstglbasefilter.c
index 155d9002b..1d57b4051 100644
--- a/gst-libs/gst/gl/gstglbasefilter.c
+++ b/gst-libs/gst/gl/gstglbasefilter.c
@@ -48,6 +48,9 @@ struct _GstGLBaseFilterPrivate
 
   gboolean gl_result;
   gboolean gl_started;
+
+  GRecMutex context_lock;
+  gboolean new_gl_context;
 };
 
 /* Properties */
@@ -91,6 +94,8 @@ static void gst_gl_base_filter_gl_stop (GstGLContext * context, gpointer data);
 static gboolean gst_gl_base_filter_default_gl_start (GstGLBaseFilter * filter);
 static void gst_gl_base_filter_default_gl_stop (GstGLBaseFilter * filter);
 
+static gboolean gst_gl_base_filter_find_gl_context_unlocked (GstGLBaseFilter *
+    filter);
 static void
 gst_gl_base_filter_class_init (GstGLBaseFilterClass * klass)
 {
@@ -131,6 +136,8 @@ gst_gl_base_filter_init (GstGLBaseFilter * filter)
   gst_base_transform_set_qos_enabled (GST_BASE_TRANSFORM (filter), TRUE);
 
   filter->priv = gst_gl_base_filter_get_instance_private (filter);
+
+  g_rec_mutex_init (&filter->priv->context_lock);
 }
 
 static void
@@ -141,6 +148,8 @@ gst_gl_base_filter_finalize (GObject * object)
   gst_caps_replace (&filter->in_caps, NULL);
   gst_caps_replace (&filter->out_caps, NULL);
 
+  g_rec_mutex_clear (&filter->priv->context_lock);
+
   G_OBJECT_CLASS (parent_class)->finalize (object);
 }
 
@@ -171,32 +180,30 @@ gst_gl_base_filter_get_property (GObject * object, guint prop_id,
   }
 }
 
-static void
-gst_gl_base_filter_set_context (GstElement * element, GstContext * context)
-{
-  GstGLBaseFilter *filter = GST_GL_BASE_FILTER (element);
-  GstGLBaseFilterClass *filter_class = GST_GL_BASE_FILTER_GET_CLASS (filter);
-
-  GST_OBJECT_LOCK (filter);
-  gst_gl_handle_set_context (element, context, &filter->display,
-      &filter->priv->other_context);
-  if (filter->display)
-    gst_gl_display_filter_gl_api (filter->display,
-        filter_class->supported_gl_api);
-  GST_OBJECT_UNLOCK (filter);
-
-  GST_ELEMENT_CLASS (parent_class)->set_context (element, context);
-}
-
 static gboolean
 _find_local_gl_context (GstGLBaseFilter * filter)
 {
+  GstGLContext *context = filter->context;
+
   if (gst_gl_query_local_gl_context (GST_ELEMENT (filter), GST_PAD_SRC,
-          &filter->context))
-    return TRUE;
+          &context)) {
+    if (context->display == filter->display) {
+      filter->context = context;
+      return TRUE;
+    }
+    if (context != filter->context)
+      gst_clear_object (&context);
+  }
+  context = filter->context;
   if (gst_gl_query_local_gl_context (GST_ELEMENT (filter), GST_PAD_SINK,
-          &filter->context))
-    return TRUE;
+          &context)) {
+    if (context->display == filter->display) {
+      filter->context = context;
+      return TRUE;
+    }
+    if (context != filter->context)
+      gst_clear_object (&context);
+  }
   return FALSE;
 }
 
@@ -211,7 +218,9 @@ gst_gl_base_filter_query (GstBaseTransform * trans, GstPadDirection direction,
     {
       if (direction == GST_PAD_SINK
           && gst_base_transform_is_passthrough (trans)) {
+        g_rec_mutex_lock (&filter->priv->context_lock);
         _find_local_gl_context (filter);
+        g_rec_mutex_unlock (&filter->priv->context_lock);
 
         return gst_pad_peer_query (GST_BASE_TRANSFORM_SRC_PAD (trans), query);
       }
@@ -220,10 +229,10 @@ gst_gl_base_filter_query (GstBaseTransform * trans, GstPadDirection direction,
     case GST_QUERY_CONTEXT:
     {
       gboolean ret;
-      GST_OBJECT_LOCK (filter);
+      g_rec_mutex_lock (&filter->priv->context_lock);
       ret = gst_gl_handle_context_query ((GstElement *) filter, query,
           filter->display, filter->context, filter->priv->other_context);
-      GST_OBJECT_UNLOCK (filter);
+      g_rec_mutex_unlock (&filter->priv->context_lock);
       if (ret)
         return TRUE;
       break;
@@ -239,17 +248,14 @@ gst_gl_base_filter_query (GstBaseTransform * trans, GstPadDirection direction,
 static void
 gst_gl_base_filter_reset (GstGLBaseFilter * filter)
 {
-  GstGLBaseFilterClass *filter_class = GST_GL_BASE_FILTER_GET_CLASS (filter);
-
+  g_rec_mutex_lock (&filter->priv->context_lock);
   if (filter->context) {
-    if (filter_class->gl_stop != NULL) {
-      gst_gl_context_thread_add (filter->context, gst_gl_base_filter_gl_stop,
-          filter);
-    }
-
+    gst_gl_context_thread_add (filter->context, gst_gl_base_filter_gl_stop,
+        filter);
     gst_object_unref (filter->context);
     filter->context = NULL;
   }
+  g_rec_mutex_unlock (&filter->priv->context_lock);
 }
 
 static gboolean
@@ -280,6 +286,7 @@ gst_gl_base_filter_gl_start (GstGLContext * context, gpointer data)
   GstGLBaseFilter *filter = GST_GL_BASE_FILTER (data);
   GstGLBaseFilterClass *filter_class = GST_GL_BASE_FILTER_GET_CLASS (filter);
 
+  GST_INFO_OBJECT (filter, "starting");
   gst_gl_insert_debug_marker (filter->context,
       "starting element %s", GST_OBJECT_NAME (filter));
 
@@ -297,6 +304,7 @@ gst_gl_base_filter_gl_stop (GstGLContext * context, gpointer data)
   GstGLBaseFilter *filter = GST_GL_BASE_FILTER (data);
   GstGLBaseFilterClass *filter_class = GST_GL_BASE_FILTER_GET_CLASS (filter);
 
+  GST_INFO_OBJECT (filter, "stopping");
   gst_gl_insert_debug_marker (filter->context,
       "stopping element %s", GST_OBJECT_NAME (filter));
 
@@ -311,33 +319,53 @@ _gl_set_caps (GstGLContext * context, GstGLBaseFilter * filter)
 {
   GstGLBaseFilterClass *filter_class = GST_GL_BASE_FILTER_GET_CLASS (filter);
 
+  GST_INFO_OBJECT (filter, "set GL caps input %" GST_PTR_FORMAT,
+      filter->in_caps);
+  GST_INFO_OBJECT (filter, "set GL caps output %" GST_PTR_FORMAT,
+      filter->out_caps);
+
   if (filter_class->gl_set_caps)
     filter->priv->gl_result =
         filter_class->gl_set_caps (filter, filter->in_caps, filter->out_caps);
 }
 
 static gboolean
-gst_gl_base_filter_decide_allocation (GstBaseTransform * trans,
-    GstQuery * query)
+gl_set_caps_unlocked (GstGLBaseFilter * filter)
 {
-  GstGLBaseFilter *filter = GST_GL_BASE_FILTER (trans);
   GstGLBaseFilterClass *filter_class = GST_GL_BASE_FILTER_GET_CLASS (filter);
 
-  if (!gst_gl_base_filter_find_gl_context (filter))
-    return FALSE;
-
   if (filter_class->gl_set_caps) {
     gst_gl_context_thread_add (filter->context,
         (GstGLContextThreadFunc) _gl_set_caps, filter);
-    if (!filter->priv->gl_result)
-      goto error;
+    return filter->priv->gl_result;
   }
 
+  return TRUE;
+}
+
+static gboolean
+gst_gl_base_filter_decide_allocation (GstBaseTransform * trans,
+    GstQuery * query)
+{
+  GstGLBaseFilter *filter = GST_GL_BASE_FILTER (trans);
+
+  g_rec_mutex_lock (&filter->priv->context_lock);
+  if (!gst_gl_base_filter_find_gl_context_unlocked (filter)) {
+    g_rec_mutex_unlock (&filter->priv->context_lock);
+    return FALSE;
+  }
+
+  if (!gl_set_caps_unlocked (filter))
+    goto error;
+
+  g_rec_mutex_unlock (&filter->priv->context_lock);
+
   return GST_BASE_TRANSFORM_CLASS (parent_class)->decide_allocation (trans,
       query);
 
 error:
   {
+    g_rec_mutex_unlock (&filter->priv->context_lock);
     GST_ELEMENT_ERROR (trans, LIBRARY, INIT,
         ("Subclass failed to initialize."), (NULL));
     return FALSE;
@@ -389,6 +417,7 @@ gst_gl_base_filter_change_state (GstElement * element,
 
   switch (transition) {
     case GST_STATE_CHANGE_READY_TO_NULL:
+      g_rec_mutex_lock (&filter->priv->context_lock);
       if (filter->priv->other_context) {
         gst_object_unref (filter->priv->other_context);
         filter->priv->other_context = NULL;
@@ -403,6 +432,7 @@ gst_gl_base_filter_change_state (GstElement * element,
         gst_object_unref (filter->context);
         filter->context = NULL;
       }
+      g_rec_mutex_unlock (&filter->priv->context_lock);
       break;
     default:
       break;
@@ -411,21 +441,49 @@ gst_gl_base_filter_change_state (GstElement * element,
   return ret;
 }
 
-/**
- * gst_gl_base_filter_find_gl_context:
- * @filter: a #GstGLBaseFilter
- *
- * Returns: Whether an OpenGL context could be retrieved or created successfully
- *
- * Since: 1.16
- */
-gboolean
-gst_gl_base_filter_find_gl_context (GstGLBaseFilter * filter)
+static void
+gst_gl_base_filter_set_context (GstElement * element, GstContext * context)
+{
+  GstGLBaseFilter *filter = GST_GL_BASE_FILTER (element);
+  GstGLBaseFilterClass *filter_class = GST_GL_BASE_FILTER_GET_CLASS (filter);
+  GstGLDisplay *old_display, *new_display;
+
+  g_rec_mutex_lock (&filter->priv->context_lock);
+  old_display = filter->display ? gst_object_ref (filter->display) : NULL;
+  gst_gl_handle_set_context (element, context, &filter->display,
+      &filter->priv->other_context);
+  if (filter->display)
+    gst_gl_display_filter_gl_api (filter->display,
+        filter_class->supported_gl_api);
+  new_display = filter->display ? gst_object_ref (filter->display) : NULL;
+
+  if (old_display && new_display) {
+    if (old_display != new_display) {
+      gst_clear_object (&filter->context);
+      if (gst_gl_base_filter_find_gl_context_unlocked (filter)) {
+        if (filter->in_caps && filter->out_caps) {
+          gl_set_caps_unlocked (filter);
+        }
+      }
+    }
+  }
+  g_rec_mutex_unlock (&filter->priv->context_lock);
+  gst_clear_object (&old_display);
+  gst_clear_object (&new_display);
+
+  GST_ELEMENT_CLASS (parent_class)->set_context (element, context);
+}
+
+static gboolean
+gst_gl_base_filter_find_gl_context_unlocked (GstGLBaseFilter * filter)
 {
   GstGLBaseFilterClass *filter_class = GST_GL_BASE_FILTER_GET_CLASS (filter);
   GError *error = NULL;
   gboolean new_context = FALSE;
 
+  GST_DEBUG_OBJECT (filter, "attempting to find an OpenGL context, existing %"
+      GST_PTR_FORMAT, filter->context);
+
   if (!filter->context)
     new_context = TRUE;
 
@@ -449,6 +507,8 @@ gst_gl_base_filter_find_gl_context (GstGLBaseFilter * filter)
     } while (!gst_gl_display_add_context (filter->display, filter->context));
     GST_OBJECT_UNLOCK (filter->display);
   }
+  GST_INFO_OBJECT (filter, "found OpenGL context %" GST_PTR_FORMAT,
+      filter->context);
 
   if (new_context || !filter->priv->gl_started) {
     if (filter->priv->gl_started)
@@ -499,3 +559,42 @@ error:
     return FALSE;
   }
 }
+
+/**
+ * gst_gl_base_filter_find_gl_context:
+ * @filter: a #GstGLBaseFilter
+ *
+ * Returns: Whether an OpenGL context could be retrieved or created successfully
+ *
+ * Since: 1.16
+ */
+gboolean
+gst_gl_base_filter_find_gl_context (GstGLBaseFilter * filter)
+{
+  gboolean ret;
+  g_rec_mutex_lock (&filter->priv->context_lock);
+  ret = gst_gl_base_filter_find_gl_context_unlocked (filter);
+  g_rec_mutex_unlock (&filter->priv->context_lock);
+  return ret;
+}
+
+/**
+ * gst_gl_base_filter_get_gl_context:
+ * @filter: a #GstGLBaseFilter
+ *
+ * Returns: (transfer full) (nullable): the #GstGLContext found by @filter
+ *
+ * Since: 1.18
+ */
+GstGLContext *
+gst_gl_base_filter_get_gl_context (GstGLBaseFilter * filter)
+{
+  GstGLContext *ret;
+
+  g_return_val_if_fail (GST_IS_GL_BASE_FILTER (filter), NULL);
+
+  g_rec_mutex_lock (&filter->priv->context_lock);
+  ret = filter->context ? gst_object_ref (filter->context) : NULL;
+  g_rec_mutex_unlock (&filter->priv->context_lock);
+  return ret;
+}
diff --git a/gst-libs/gst/gl/gstglbasefilter.h b/gst-libs/gst/gl/gstglbasefilter.h
index 15361ade1..57fb3df5b 100644
--- a/gst-libs/gst/gl/gstglbasefilter.h
+++ b/gst-libs/gst/gl/gstglbasefilter.h
@@ -70,6 +70,8 @@ struct _GstGLBaseFilter
  * @gl_start: called in the GL thread to setup the element GL state.
  * @gl_stop: called in the GL thread to setup the element GL state.
  * @gl_set_caps: called in the GL thread when caps are set on @filter.
+ *               Note: this will also be called when changing OpenGL contexts
+ *               where #GstBaseTransform::set_caps may not.
  *
  * The base class for GStreamer GL Filter.
  */
@@ -90,6 +92,8 @@ struct _GstGLBaseFilterClass
 
 GST_GL_API
 gboolean        gst_gl_base_filter_find_gl_context          (GstGLBaseFilter * filter);
+GST_GL_API
+GstGLContext *  gst_gl_base_filter_get_gl_context           (GstGLBaseFilter * filter);
 
 G_END_DECLS
 
diff --git a/tests/check/elements/glfilter.c b/tests/check/elements/glfilter.c
new file mode 100644
index 000000000..0d8d67687
--- /dev/null
+++ b/tests/check/elements/glfilter.c
@@ -0,0 +1,131 @@
+/* GStreamer
+ *
+ * Copyright (C) 2019 Matthew Waters <matthew@centricular.com>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with this library; if not, write to the
+ * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
+ * Boston, MA 02110-1301, USA.
+ */
+
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <gst/gst.h>
+#include <gst/gl/gl.h>
+#include <gst/check/gstcheck.h>
+#include <gst/check/gstharness.h>
+
+static void
+replace_display (GstHarness * h)
+{
+  GstContext *new_context;
+  GstGLDisplay *new_display;
+  GstGLContext *expected, *gl_context;
+  GstBuffer *buf;
+
+  /* replaces the GstGLDisplay used by @h with verification */
+
+  buf = gst_harness_create_buffer (h, 4);
+  buf = gst_harness_push_and_pull (h, buf);
+  fail_unless (buf != NULL);
+  gst_clear_buffer (&buf);
+
+  g_object_get (G_OBJECT (h->element), "context", &gl_context, NULL);
+  fail_unless (gl_context != NULL);
+  gst_clear_object (&gl_context);
+
+  new_display = gst_gl_display_new ();
+  fail_unless (gst_gl_display_create_context (new_display, NULL, &expected,
+          NULL));
+  fail_unless (expected != NULL);
+  gst_gl_display_add_context (new_display, expected);
+
+  new_context = gst_context_new (GST_GL_DISPLAY_CONTEXT_TYPE, TRUE);
+  gst_context_set_gl_display (new_context, new_display);
+
+  gst_element_set_context (h->element, new_context);
+  gst_context_unref (new_context);
+  new_context = NULL;
+
+  buf = gst_harness_create_buffer (h, 4);
+  buf = gst_harness_push_and_pull (h, buf);
+  fail_unless (buf != NULL);
+  gst_clear_buffer (&buf);
+
+  g_object_get (G_OBJECT (h->element), "context", &gl_context, NULL);
+  fail_unless (gl_context != NULL);
+
+  fail_unless (gl_context == expected);
+  fail_unless (new_display == gl_context->display);
+
+  gst_object_unref (expected);
+  gst_object_unref (gl_context);
+  gst_object_unref (new_display);
+}
+
+GST_START_TEST (test_glupload_display_replace)
+{
+  GstHarness *upload;
+
+  upload = gst_harness_new ("glupload");
+  gst_harness_set_caps_str (upload, "video/x-raw,format=RGBA,width=1,height=1",
+      "video/x-raw(memory:GLMemory),format=RGBA,width=1,height=1");
+
+  replace_display (upload);
+
+  gst_harness_teardown (upload);
+}
+
+GST_END_TEST;
+
+GST_START_TEST (test_glcolorconvert_display_replace)
+{
+  GstHarness *convert;
+
+  convert = gst_harness_new ("glcolorconvert");
+  gst_harness_set_caps_str (convert,
+      "video/x-raw(memory:GLMemory),format=RGBA,width=1,height=1,texture-target=2D",
+      "video/x-raw(memory:GLMemory),format=RGBA,width=1,height=1,texture-target=2D");
+
+  replace_display (convert);
+
+  gst_harness_teardown (convert);
+}
+
+GST_END_TEST;
+
+static Suite *
+glfilter_suite (void)
+{
+  Suite *s = suite_create ("glfilter");
+  TCase *tc = tcase_create ("general");
+
+  tcase_add_test (tc, test_glupload_display_replace);
+  tcase_add_test (tc, test_glcolorconvert_display_replace);
+  suite_add_tcase (s, tc);
+
+  return s;
+}
+
+int
+main (int argc, char **argv)
+{
+  Suite *s;
+  g_setenv ("GST_GL_XINITTHREADS", "1", TRUE);
+  gst_check_init (&argc, &argv);
+  s = glfilter_suite ();
+  return gst_check_run_suite (s, "glfilter", __FILE__);
+}
diff --git a/tests/check/meson.build b/tests/check/meson.build
index 31fb67f15..c3f5bdd9a 100644
--- a/tests/check/meson.build
+++ b/tests/check/meson.build
@@ -99,6 +99,7 @@ if build_gstgl and host_machine.system() != 'windows'
     [ 'elements/glimagesink.c', not build_gstgl, [gstgl_dep]],
     [ 'elements/glbin.c', not build_gstgl ],
     [ 'pipelines/gl-launch-lines.c', not build_gstgl ],
+    [ 'elements/glfilter.c', not build_gstgl, [gstgl_dep]],
   ]
 endif
 
-- 
2.25.4