/* -*-c++-*- */
/* osgEarth - Dynamic map generation toolkit for OpenSceneGraph
 * Copyright 2008-2011 Pelican Mapping
 * http://osgearth.org
 *
 * osgEarth 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 2 of the License, or
 * (at your option) any later version.
 *
 * This program 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 this program.  If not, see <http://www.gnu.org/licenses/>
 */

#ifndef OSGEARTH_CLAMPABLE_NODE_H
#define OSGEARTH_CLAMPABLE_NODE_H 1

#include <osgEarth/Common>
#include <osgEarth/DepthOffset>
#include <osgEarth/OverlayNode>
#include <osg/Group>

namespace osgEarth
{
    class MapNode;

    /**
     * Node graph that can be "clamped" on the MapNode terrain
     * using the overlay decorator.
     *
     * Usage: Create this node and put it anywhere in the scene graph. The
     * subgraph of this node will be draped on the MapNode's terrain.
     */
    class OSGEARTH_EXPORT ClampableNode : public OverlayNode
    {
    public:
        /**
         * Constructs a new clampable node.
         */
        ClampableNode( MapNode* mapNode, bool clamped =true );

    public:
        /** Depth Offsetting properties. Clamped geometry is automatically
         *  subjected to depth offsetting to mitigate z-buffer conflicts */
        DepthOffsetOptions& depthOffset() { dirtyDepthOffsetOptions(); return _do; }
        const DepthOffsetOptions& depthOffset() const { return _do; }
        
        /** Automatically attempt to select a minimum bias based on an analysis
         *  of the subgraph's geometry. */
        void setAutoCalculateDepthOffset();

        /** Backwards compatibility */
        void setClamped( bool value ) { setActive(value); }
        bool getClamped() const { return getActive(); }

    public: // osg::Node

        virtual osg::BoundingSphere computeBound() const;

        virtual void traverse(osg::NodeVisitor& nv);

    protected:
        /** dtor */
        virtual ~ClampableNode() { }

        bool _autoBias;
        mutable osg::ref_ptr<osg::Uniform> _biasUniform;
        mutable osg::ref_ptr<osg::Uniform> _rangeUniform;

        mutable DepthOffsetOptions _do;
        bool _doDirty;

        void init();
        void dirtyDepthOffsetOptions();
        void applyDepthOffsetOptions();
    };

} // namespace osgEarth

#endif // OSGEARTH_CLAMPABLE_NODE_H
