From a0a133288e0e1e45f323a7252c36b5624292b5b1 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Sebastian=20Dr=C3=B6ge?= <sebastian@centricular.com>
Date: Thu, 24 Apr 2014 18:28:34 +0200
Subject: [PATCH] gl/x11: Block rendering until swapbuffers is called and don't
 go via X11 events as unneeded indirection

This should fix QoS problems, where basesink believed it was rendering with
20FPS but actually we were just queueing up X11 Expose events and only once
in a while something was rendered.
---
 gst-libs/gst/gl/x11/gstglwindow_x11.c | 89 ++++++++++++---------------
 1 file changed, 41 insertions(+), 48 deletions(-)

diff --git a/gst-libs/gst/gl/x11/gstglwindow_x11.c b/gst-libs/gst/gl/x11/gstglwindow_x11.c
index 1e7a4f7e59..fd08b7d2a0 100644
--- a/gst-libs/gst/gl/x11/gstglwindow_x11.c
+++ b/gst-libs/gst/gl/x11/gstglwindow_x11.c
@@ -367,43 +367,36 @@ gst_gl_window_x11_draw_unlocked (GstGLWindow * window, guint width,
 
   if (g_main_loop_is_running (window_x11->loop)
       && window_x11->allow_extra_expose_events) {
-    XEvent event;
-    XWindowAttributes attr;
+    if (window->draw) {
+      GstGLContext *context = gst_gl_window_get_context (window);
+      GstGLContextClass *context_class = GST_GL_CONTEXT_GET_CLASS (context);
 
-    XGetWindowAttributes (window_x11->device, window_x11->internal_win_id,
-        &attr);
+      window->draw (window->draw_data);
+      context_class->swap_buffers (context);
 
-    event.xexpose.type = Expose;
-    event.xexpose.send_event = TRUE;
-    event.xexpose.display = window_x11->device;
-    event.xexpose.window = window_x11->internal_win_id;
-    event.xexpose.x = attr.x;
-    event.xexpose.y = attr.y;
-    event.xexpose.width = attr.width;
-    event.xexpose.height = attr.height;
-    event.xexpose.count = 0;
-
-    XSendEvent (window_x11->device, window_x11->internal_win_id, FALSE,
-        ExposureMask, &event);
-    XSync (window_x11->device, FALSE);
+      gst_object_unref (context);
+    }
   }
 }
 
-/* Not called by the gl thread */
-void
-gst_gl_window_x11_draw (GstGLWindow * window, guint width, guint height)
+struct draw
 {
-  GstGLWindowX11 *window_x11;
+  GstGLWindowX11 *window;
+  guint width, height;
+};
 
-  window_x11 = GST_GL_WINDOW_X11 (window);
+static void
+draw_cb (gpointer data)
+{
+  struct draw *draw_data = data;
+  GstGLWindowX11 *window_x11 = draw_data->window;
+  guint width = draw_data->width;
+  guint height = draw_data->height;
 
   if (g_main_loop_is_running (window_x11->loop)) {
-    XEvent event;
     XWindowAttributes attr;
 
-    g_mutex_lock (&window_x11->disp_send_lock);
-
-    XGetWindowAttributes (window_x11->disp_send, window_x11->internal_win_id,
+    XGetWindowAttributes (window_x11->device, window_x11->internal_win_id,
         &attr);
 
     if (!window_x11->visible) {
@@ -411,24 +404,24 @@ gst_gl_window_x11_draw (GstGLWindow * window, guint width, guint height)
       if (!window_x11->parent_win) {
         attr.width = width;
         attr.height = height;
-        XResizeWindow (window_x11->disp_send, window_x11->internal_win_id,
+        XResizeWindow (window_x11->device, window_x11->internal_win_id,
             attr.width, attr.height);
-        XSync (window_x11->disp_send, FALSE);
+        XSync (window_x11->device, FALSE);
       }
 
-      XMapWindow (window_x11->disp_send, window_x11->internal_win_id);
+      XMapWindow (window_x11->device, window_x11->internal_win_id);
       window_x11->visible = TRUE;
     }
 
     if (window_x11->parent_win) {
       XWindowAttributes attr_parent;
-      XGetWindowAttributes (window_x11->disp_send, window_x11->parent_win,
+      XGetWindowAttributes (window_x11->device, window_x11->parent_win,
           &attr_parent);
 
       if (attr.width != attr_parent.width || attr.height != attr_parent.height) {
-        XMoveResizeWindow (window_x11->disp_send, window_x11->internal_win_id,
+        XMoveResizeWindow (window_x11->device, window_x11->internal_win_id,
             0, 0, attr_parent.width, attr_parent.height);
-        XSync (window_x11->disp_send, FALSE);
+        XSync (window_x11->device, FALSE);
 
         attr.width = attr_parent.width;
         attr.height = attr_parent.height;
@@ -438,24 +431,24 @@ gst_gl_window_x11_draw (GstGLWindow * window, guint width, guint height)
       }
     }
 
-    event.xexpose.type = Expose;
-    event.xexpose.send_event = TRUE;
-    event.xexpose.display = window_x11->disp_send;
-    event.xexpose.window = window_x11->internal_win_id;
-    event.xexpose.x = attr.x;
-    event.xexpose.y = attr.y;
-    event.xexpose.width = attr.width;
-    event.xexpose.height = attr.height;
-    event.xexpose.count = 0;
-
-    XSendEvent (window_x11->disp_send, window_x11->internal_win_id, FALSE,
-        ExposureMask, &event);
-    XSync (window_x11->disp_send, FALSE);
-
-    g_mutex_unlock (&window_x11->disp_send_lock);
+    gst_gl_window_x11_draw_unlocked (GST_GL_WINDOW (window_x11), width, height);
   }
 }
 
+/* Not called by the gl thread */
+void
+gst_gl_window_x11_draw (GstGLWindow * window, guint width, guint height)
+{
+  struct draw draw_data;
+
+  draw_data.window = GST_GL_WINDOW_X11 (window);
+  draw_data.width = width;
+  draw_data.height = height;
+
+  /* Call from the GL thread */
+  gst_gl_window_send_message (window, (GstGLWindowCB) draw_cb, &draw_data);
+}
+
 void
 gst_gl_window_x11_run (GstGLWindow * window)
 {
@@ -568,6 +561,7 @@ gst_gl_window_x11_handle_event (GstGLWindowX11 * window_x11)
         if (!event.xexpose.send_event)
           break;
 
+        /* We need to redraw on expose */
         if (window->draw) {
           context = gst_gl_window_get_context (window);
           context_class = GST_GL_CONTEXT_GET_CLASS (context);
@@ -586,7 +580,6 @@ gst_gl_window_x11_handle_event (GstGLWindowX11 * window_x11)
       default:
         GST_DEBUG ("unknown XEvent type: %u", event.type);
         break;
-
     }                           // switch
   }                             // while running