[ADD] - added new callback for automatic propagation of viewport updates along...

[ADD] - added new callback for automatic propagation of viewport updates along multiple cameras or nodes supporting it.

src/graphicsEngine/callbacks/WGEViewportCallback.cpp

+//---------------------------------------------------------------------------
+//
+// Project: OpenWalnut ( http://www.openwalnut.org )
+//
+// Copyright 2009 OpenWalnut Community, BSV@Uni-Leipzig and CNCF@MPI-CBS
+// For more information see http://www.openwalnut.org/copying
+//
+// This file is part of OpenWalnut.
+//
+// OpenWalnut is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// OpenWalnut 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 Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with OpenWalnut. If not, see <http://www.gnu.org/licenses/>.
+//
+//---------------------------------------------------------------------------
+
+#include "WGEViewportCallback.h"
+

src/graphicsEngine/callbacks/WGEViewportCallback.h

+//---------------------------------------------------------------------------
+//
+// Project: OpenWalnut ( http://www.openwalnut.org )
+//
+// Copyright 2009 OpenWalnut Community, BSV@Uni-Leipzig and CNCF@MPI-CBS
+// For more information see http://www.openwalnut.org/copying
+//
+// This file is part of OpenWalnut.
+//
+// OpenWalnut is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// OpenWalnut 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 Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with OpenWalnut. If not, see <http://www.gnu.org/licenses/>.
+//
+//---------------------------------------------------------------------------
+
+#ifndef WGEVIEWPORTCALLBACK_H
+#define WGEVIEWPORTCALLBACK_H
+
+#include <osg/Camera>
+#include <osg/Node>
+
+#include "../WExportWGE.h"
+
+/**
+ * This callback is useful to update viewport information on several nodes supporting it. The specified type must support an setViewport method.
+ * This is especially useful to keep offscreen render cameras in sync with the scene cam or to update HUD viewport information. Note that the
+ * order of execution of callbacks for a node can cause problems as the new viewport might get set after it is needed.
+ *
+ * \tparam T the type supporting ::setViewport( osg::Viewport* vp ).
+ * \tparam Source the type from who the viewport should be acquired by using osg::Viewport* getViewport()
+ */
+template < typename T, typename Source = osg::Camera >
+class WGEViewportCallback: public osg::NodeCallback
+{
+public:
+    /**
+     * Creates new instance of viewport callback.
+     *
+     * \param reference set the viewport to the one of the reference camera.
+     */
+    explicit WGEViewportCallback( osg::ref_ptr< Source > reference );
+
+    /**
+     * Destructor.
+     */
+    virtual ~WGEViewportCallback();
+
+     /**
+     * This operator gets called by OSG every update cycle. It applies the viewport.
+     *
+     * \param node the osg node
+     * \param nv the node visitor
+     */
+    virtual void operator()( osg::Node* node, osg::NodeVisitor* nv );
+
+protected:
+private:
+    /**
+     * The reference camera to use.
+     */
+    osg::ref_ptr< Source > m_reference;
+};
+
+template < typename T, typename Source >
+WGEViewportCallback< T, Source >::WGEViewportCallback( osg::ref_ptr< Source > reference ):
+    osg::NodeCallback(),
+    m_reference( reference )
+{
+    // initialize members
+}
+
+template < typename T, typename Source >
+WGEViewportCallback< T, Source >::~WGEViewportCallback()
+{
+    // cleanup
+}
+
+template < typename T, typename Source >
+void WGEViewportCallback< T, Source >::operator()( osg::Node* node, osg::NodeVisitor* nv )
+{
+    osg::ref_ptr< T > t = dynamic_cast< T* >( node );
+    if ( t )
+    {
+        t->setViewport( m_reference->getViewport() );
+    }
+    traverse( node, nv );
+}
+
+#endif  // WGEVIEWPORTCALLBACK_H
+