From b1a5ae7c0d1ef9fa0e681b425168bba4cb362f66 Mon Sep 17 00:00:00 2001
From: =?utf8?q?Sebastian=20Dr=C3=B6ge?= <sebastian@centricular.com>
Date: Mon, 29 Sep 2014 09:33:42 +0300
Subject: [PATCH] gl/cocoa: Update viewport according to the current clipping

We have to update the GL viewport if the NSView is only partially
visible. Otherwise the content of the frame will be visibly offset.
---
 gst-libs/gst/gl/cocoa/gstglwindow_cocoa.m | 40 +++++++++++++++++++++----------
 1 file changed, 28 insertions(+), 12 deletions(-)

diff --git a/gst-libs/gst/gl/cocoa/gstglwindow_cocoa.m b/gst-libs/gst/gl/cocoa/gstglwindow_cocoa.m
index df48144..f0333b9 100644
--- a/gst-libs/gst/gl/cocoa/gstglwindow_cocoa.m
+++ b/gst-libs/gst/gl/cocoa/gstglwindow_cocoa.m
@@ -83,6 +83,9 @@ struct _GstGLWindowCocoaPrivate
   gboolean visible;
   GMainContext *main_context;
   GMainLoop *loop;
+
+  GLint viewport_dim[4];
+  NSRect bounds, visibleRect;
 };
 
 static void
@@ -505,7 +508,6 @@ struct resize
 {
   GstGLWindowCocoa * window;
   NSRect bounds, visibleRect;
-  NSSize frameSize;
 };
 
 static void
@@ -518,12 +520,29 @@ resize_cb (gpointer data)
   NSOpenGLContext * glContext = (NSOpenGLContext *) gst_gl_context_get_gl_context (context);
 
   if (g_main_loop_is_running (window_cocoa->priv->loop) && ![window_cocoa->priv->internal_win_id isClosed]) {
-    /* FIXME: Need to adjust viewport for clipping here */
-    if (window->resize) {
-      window->resize (window->resize_data, resize_data->bounds.size.width, resize_data->bounds.size.height);
-    }
+    const GstGLFuncs *gl;
 
     [glContext update];
+
+    if (window_cocoa->priv->bounds.size.width != resize_data->bounds.size.width ||
+       window_cocoa->priv->bounds.size.height != resize_data->bounds.size.height ||
+       window_cocoa->priv->visibleRect.origin.x != resize_data->visibleRect.origin.x ||
+       window_cocoa->priv->visibleRect.origin.y != resize_data->visibleRect.origin.y) {
+      gl = context->gl_vtable;
+
+      if (window->resize) {
+        window->resize (window->resize_data, resize_data->bounds.size.width, resize_data->bounds.size.height);
+        gl->GetIntegerv (GL_VIEWPORT, window_cocoa->priv->viewport_dim);
+      }
+
+      gl->Viewport (window_cocoa->priv->viewport_dim[0] - resize_data->visibleRect.origin.x,
+                    window_cocoa->priv->viewport_dim[1] - resize_data->visibleRect.origin.y,
+                    window_cocoa->priv->viewport_dim[2], window_cocoa->priv->viewport_dim[3]);
+
+      window_cocoa->priv->visibleRect = resize_data->visibleRect;
+      window_cocoa->priv->bounds = resize_data->bounds;
+    }
+
     GST_GL_WINDOW (window_cocoa)->draw (GST_GL_WINDOW (window_cocoa)->draw_data);
     [glContext flushBuffer];
   }
@@ -542,21 +561,18 @@ resize_cb (gpointer data)
   if (window->resize) {
     NSRect bounds = [self bounds];
     NSRect visibleRect = [self visibleRect];
-    NSSize frameSize = [self frame].size;
     struct resize *resize_data = g_new (struct resize, 1);
 
-    GST_DEBUG_OBJECT (window, "Window resized: bounds %lf %lf %lf %lf, "
-                      "visibleRect %lf %lf %lf %lf, frame size %lf %lf",
+    GST_DEBUG_OBJECT (window, "Window resized: bounds %lf %lf %lf %lf "
+                      "visibleRect %lf %lf %lf %lf",
                       bounds.origin.x, bounds.origin.y,
                       bounds.size.width, bounds.size.height,
                       visibleRect.origin.x, visibleRect.origin.y,
-                      visibleRect.size.width, visibleRect.size.height,
-                      frameSize.width, frameSize.height);
+                      visibleRect.size.width, visibleRect.size.height);
 
     resize_data->window = window_cocoa;
     resize_data->bounds = bounds;
     resize_data->visibleRect = visibleRect;
-    resize_data->frameSize = frameSize;
 
     gst_gl_window_send_message_async (GST_GL_WINDOW (window_cocoa), (GstGLWindowCB) resize_cb, resize_data, (GDestroyNotify) g_free);
   }
@@ -567,7 +583,7 @@ resize_cb (gpointer data)
 }
 
 - (BOOL) isFlipped {
-    return YES;
+    return NO;
 }
 
 @end
-- 
2.7.4