libosgearth-dev 2.7.0+dfsg-2+b3 / usr / include / osgEarth / CullingUtils

/* -*-c++-*- */
/* osgEarth - Dynamic map generation toolkit for OpenSceneGraph
 * Copyright 2015 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_CULLING_UTILS_H
#define OSGEARTH_CULLING_UTILS_H 1

#include <osgEarth/Common>
#include <osgEarth/optional>
#include <osgEarth/SpatialReference>
#include <osg/NodeCallback>
#include <osg/ClusterCullingCallback>
#include <osg/CoordinateSystemNode>
#include <osg/MatrixTransform>
#include <osg/Vec3d>
#include <osg/Vec3>
#include <osg/ClipPlane>
#include <osgUtil/CullVisitor>

namespace osgEarth
{    
    /**
     * A customized CCC that works correctly under an RTT camera and also with 
     * an orthographic projection matrix.
     */
    class SuperClusterCullingCallback : public osg::ClusterCullingCallback
    {
    public:
        bool cull(osg::NodeVisitor* nv, osg::Drawable* , osg::State*) const;
    };


    /**
     * Utility functions for creating cluster cullers
     */
    class OSGEARTH_EXPORT ClusterCullingFactory
    {
    public:
        /**
         * Creates a cluster culling callback based on the data in a node graph.
         * NOTE! Never put a CCC somewhere where it will be under a transform. They
         * only work in absolute world space.
         */
        static osg::NodeCallback* create( osg::Node* node, const osg::Vec3d& ecefControlPoint );

        /**
         * Same as above, but uses another method to compute the parameters. There should only
         * be one, but we need to investigate to see which is the better algorithm. Keeping this
         * for now since it works with the feature setup..
         */
        static osg::NodeCallback* create2( osg::Node* node, const osg::Vec3d& ecefControlPoint );

        /**
         * Creates a cluster culling callback and installs it on the node. If the node is
         * a transform, it will create a group above the transform and install the callback
         * on that group instead.
         */
        static osg::Node* createAndInstall( osg::Node* node, const osg::Vec3d& ecefControlPoint );

        /**
         * Creates a cluster culling callback with the standard parameters.
         */
        static osg::NodeCallback* create(const osg::Vec3& controlPoint, const osg::Vec3& normal, float deviation, float radius);
    };

    
    /**
     * A simple culling-plane callback (a simpler version of ClusterCullingCallback)
     */
    struct OSGEARTH_EXPORT CullNodeByNormal : public osg::NodeCallback {
        osg::Vec3d _normal;
        CullNodeByNormal( const osg::Vec3d& normal );
        void operator()(osg::Node* node, osg::NodeVisitor* nv);
    };

    struct CullDrawableByNormal : public osg::Drawable::CullCallback {
        osg::Vec3d _normal;
        CullDrawableByNormal( const osg::Vec3d& normal ) : _normal(normal) { }
        bool cull(osg::NodeVisitor* nv, osg::Drawable* drawable, osg::State* state) const {
            return nv && nv->getEyePoint() * _normal <= 0;
        }
    };

    struct OSGEARTH_EXPORT CullNodeByFrameNumber : public osg::NodeCallback {
        unsigned _frame;
        CullNodeByFrameNumber() : _frame(0) { }
        void operator()( osg::Node* node, osg::NodeVisitor* nv ) {
            if ( nv->getFrameStamp()->getFrameNumber() - _frame <= 1 )
                traverse(node, nv);
        }
    };

    struct DisableSubgraphCulling : public osg::NodeCallback {
        void operator()(osg::Node* n, osg::NodeVisitor* v);
    };

    struct StaticBound : public osg::Node::ComputeBoundingSphereCallback {
        osg::BoundingSphere _bs;
        StaticBound(const osg::BoundingSphere& bs) : _bs(bs) { }
        osg::BoundingSphere computeBound(const osg::Node&) const { return _bs; }
    };

    // a cull callback that prevents objects from being included in the near/fear clip
    // plane calculates that OSG does.
    struct OSGEARTH_EXPORT DoNotComputeNearFarCullCallback : public osg::NodeCallback
    {
        void operator()(osg::Node* node, osg::NodeVisitor* nv);
    };

    /**
     * Simple occlusion culling callback that does a ray interseciton between the eyepoint
     * and a world point and doesn't draw if there are intersections with the node.
     */
    struct OSGEARTH_EXPORT OcclusionCullingCallback : public osg::NodeCallback {
        OcclusionCullingCallback( const SpatialReference* srs, const osg::Vec3d& world, osg::Node* node);

        const osg::Vec3d& getWorld() const;
        void setWorld( const osg::Vec3d& world);
        double getMaxAltitude() const;
        void setMaxAltitude( double value);
        void operator()(osg::Node* node, osg::NodeVisitor* nv);

        /**
        * Gets the maximum number of ms that the OcclusionCullingCallback can run on each frame.
        */
        static double getMaxFrameTime();

        /**
        * Sets the maximum number of ms that the OcclusionCullingCallback can run on each frame.
        * @param ms
        *     The maximum number of milliseconds to run the OcclusionCullingCallback on each frame. 
        */
        static void setMaxFrameTime( double ms );

    private:

        osg::ref_ptr< osg::Node > _node;
        osg::ref_ptr< const osgEarth::SpatialReference > _srs;
        osg::Vec3d _world;
        osg::Vec3d _prevWorld;
        osg::Vec3d _prevEye;
        bool _visible;
        double _maxAltitude;
        static double _maxFrameTime;
    };

    /**
     * Culling utilities.
     */
    struct OSGEARTH_EXPORT Culling
    {
        static osgUtil::CullVisitor* asCullVisitor(osg::NodeVisitor* nv);
        static osgUtil::CullVisitor* asCullVisitor(osg::NodeVisitor& nv) { return asCullVisitor(&nv); }

        /** General user data to calculate once and pass down with a CullVisitor. */
        struct CullUserData : public osg::Referenced
        {
            optional<double> _cameraAltitude;
        };

        static CullUserData* getCullUserData(osgUtil::CullVisitor* cv) {
            return cv ? dynamic_cast<CullUserData*>(cv->getUserData()) : 0L; }
    };

    /**
     * Node Visitor that proxies the CullVisitor but uses a separate
     * frustum for bounds-culling.
     */
    class ProxyCullVisitor : public osg::NodeVisitor, public osg::CullStack
    {
    private:
        osgUtil::CullVisitor* _cv;
        osg::Polytope         _proxyFrustum;
        osg::Polytope         _proxyProjFrustum;
        osg::Matrix           _proxyModelViewMatrix;
        osg::Matrix           _proxyProjMatrix;

    public:
        ProxyCullVisitor( osgUtil::CullVisitor* cv, const osg::Matrix& proj, const osg::Matrix& view );

        // access to the underlying cull visitor.
        osgUtil::CullVisitor* getCullVisitor() { return _cv; }

    public: // proxy functions:
        osg::Vec3 getEyePoint() const;
        osg::Vec3 getViewPoint() const;
        float getDistanceToEyePoint(const osg::Vec3& pos, bool useLODScale) const;
        float getDistanceFromEyePoint(const osg::Vec3& pos, bool useLODScale) const;
        float getDistanceToViewPoint(const osg::Vec3& pos, bool useLODScale) const;

    protected: // custom culling functions:

        bool isCulledByProxyFrustum(osg::Node& node);
        bool isCulledByProxyFrustum(const osg::BoundingBox& bbox);
        
        osgUtil::CullVisitor::value_type distance(const osg::Vec3& coord,const osg::Matrix& matrix);

        void handle_cull_callbacks_and_traverse(osg::Node& node);

        void apply(osg::Node& node);
        void apply(osg::Transform& node);
        void apply(osg::Geode& node);
    };


    /**
     * Horizon culling in a shader program.
     */
    class OSGEARTH_EXPORT HorizonCullingProgram
    {
    public:
        static void install( osg::StateSet* stateset );
        static void remove ( osg::StateSet* stateset );
    };


    /**
     * Group that lets you adjust the LOD scale on its children.
     */
    class OSGEARTH_EXPORT LODScaleGroup : public osg::Group
    {
    public:
        LODScaleGroup();

        /**
         * Factor by which to multiply the camera's LOD scale.
         */
        void setLODScaleFactor( float value ) { _scaleFactor = value; }
        float getLODScaleFactor() const { return _scaleFactor; }

    public: // osg::Group
        virtual void traverse(osg::NodeVisitor& nv);

    protected:
        virtual ~LODScaleGroup() { }

    private:
        float _scaleFactor;
    };


    
    /**
     * Cull callback that sets a clip plane at the visible horizon
     * of the Ellipsoid.
     */
    class OSGEARTH_EXPORT ClipToGeocentricHorizon : public osg::NodeCallback
    {
    public:
        ClipToGeocentricHorizon(
            const osgEarth::SpatialReference* srs,
            osg::ClipPlane*                   clipPlane);
        
        void operator()(osg::Node* node, osg::NodeVisitor* nv);

    protected:
        osg::Vec3d                        _radii;
        osg::observer_ptr<osg::ClipPlane> _clipPlane;
    };
}

#endif // OSGEARTH_CULLING_UTILS_H