glcontext: Store the updated area in the right place

We need to store the region *before* adding our own damage area, because
we want to only store the changes of this frame, not the whole history.

So do it in the same place Vulkan does it.

Fixes #1900

1 files changed, 6 insertions, 5 deletions

diff --git a/gdk/gdkglcontext.c b/gdk/gdkglcontext.c
index b36b721f49..12a77c827a 100644
--- a/gdk/gdkglcontext.c
+++ b/gdk/gdkglcontext.c
@@ -310,6 +310,12 @@ gdk_gl_context_real_begin_frame (GdkDrawContext *draw_context,
     }
 
   damage = GDK_GL_CONTEXT_GET_CLASS (context)->get_damage (context);
+
+  if (context->old_updated_area[1])
+    cairo_region_destroy (context->old_updated_area[1]);
+  context->old_updated_area[1] = context->old_updated_area[0];
+  context->old_updated_area[0] = cairo_region_copy (region);
+
   cairo_region_union (region, damage);
   cairo_region_destroy (damage);
 
@@ -341,11 +347,6 @@ gdk_gl_context_real_end_frame (GdkDrawContext *draw_context,
       GDK_DRAW_CONTEXT_GET_CLASS (GDK_DRAW_CONTEXT (shared))->end_frame (GDK_DRAW_CONTEXT (shared), painted);
       return;
     }
-
-  if (context->old_updated_area[1])
-    cairo_region_destroy (context->old_updated_area[1]);
-  context->old_updated_area[1] = context->old_updated_area[0];
-  context->old_updated_area[0] = cairo_region_reference (painted);
 }
 
 static void