From 7463ebad1d0c203fd892d7d54a57ffa41208c1df Mon Sep 17 00:00:00 2001
From: Thomas Geymayer <tomgey@gmail.com>
Date: Sat, 1 Sep 2012 16:50:21 +0200
Subject: [PATCH] Canvas: Only use cull callback if it's still valid

---
 src/Canvas/canvas.cxx               | 2 +-
 src/Canvas/canvas.hxx               | 8 +++++---
 src/Canvas/elements/CanvasImage.cxx | 5 +++--
 3 files changed, 9 insertions(+), 6 deletions(-)

diff --git a/src/Canvas/canvas.cxx b/src/Canvas/canvas.cxx
index eca171c38..1e64f7958 100644
--- a/src/Canvas/canvas.cxx
+++ b/src/Canvas/canvas.cxx
@@ -73,7 +73,7 @@ Canvas::CullCallback::CullCallback(CameraCullCallback* camera_cull):
 void Canvas::CullCallback::operator()( osg::Node* node,
                                        osg::NodeVisitor* nv )
 {
-  if( nv->getTraversalMask() & simgear::MODEL_BIT )
+  if( (nv->getTraversalMask() & simgear::MODEL_BIT) && _camera_cull.valid() )
     _camera_cull->enableRendering();
 
   traverse(node, nv);
diff --git a/src/Canvas/canvas.hxx b/src/Canvas/canvas.hxx
index 29d9ee93e..dbfae12fe 100644
--- a/src/Canvas/canvas.hxx
+++ b/src/Canvas/canvas.hxx
@@ -27,6 +27,7 @@
 
 #include <simgear/props/propertyObject.hxx>
 #include <osg/NodeCallback>
+#include <osg/observer_ptr>
 
 #include <memory>
 #include <string>
@@ -66,6 +67,7 @@ class Canvas:
         virtual void operator()(osg::Node* node, osg::NodeVisitor* nv);
     };
     typedef osg::ref_ptr<CameraCullCallback> CameraCullCallbackPtr;
+    typedef osg::observer_ptr<CameraCullCallback> CameraCullCallbackWeakPtr;
 
     /**
      * This callback is installed on every placement of the canvas in the
@@ -78,7 +80,7 @@ class Canvas:
         CullCallback(CameraCullCallback* camera_cull);
 
       private:
-        CameraCullCallback *_camera_cull;
+        CameraCullCallbackWeakPtr _camera_cull;
 
         virtual void operator()(osg::Node* node, osg::NodeVisitor* nv);
     };
@@ -91,10 +93,10 @@ class Canvas:
 
     int getSizeX() const
     { return _size_x; }
-  
+
     int getSizeY() const
     { return _size_y; }
-  
+
     void setSizeX(int sx);
     void setSizeY(int sy);
 
diff --git a/src/Canvas/elements/CanvasImage.cxx b/src/Canvas/elements/CanvasImage.cxx
index 77ddbce13..17dd5e0cf 100644
--- a/src/Canvas/elements/CanvasImage.cxx
+++ b/src/Canvas/elements/CanvasImage.cxx
@@ -43,7 +43,7 @@ class CullCallback:
     CullCallback(Canvas::CameraCullCallback* camera_cull);
 
   private:
-    Canvas::CameraCullCallback *_camera_cull;
+    Canvas::CameraCullCallbackWeakPtr _camera_cull;
 
     virtual bool cull( osg::NodeVisitor* nv,
                        osg::Drawable* drawable,
@@ -62,7 +62,8 @@ bool CullCallback::cull( osg::NodeVisitor* nv,
                          osg::Drawable* drawable,
                          osg::RenderInfo* renderInfo ) const
 {
-  _camera_cull->enableRendering();
+  if( _camera_cull.valid() )
+    _camera_cull->enableRendering();
 
   // TODO check if window/image should be culled
   return false;