/* OpenSceneGraph example, osgshadow.
*
*  Permission is hereby granted, free of charge, to any person obtaining a copy
*  of this software and associated documentation files (the "Software"), to deal
*  in the Software without restriction, including without limitation the rights
*  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
*  copies of the Software, and to permit persons to whom the Software is
*  furnished to do so, subject to the following conditions:
*
*  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
*  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
*  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
*  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
*  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
*  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
*  THE SOFTWARE.
*/

#include <osg/ArgumentParser>
#include <osg/ComputeBoundsVisitor>
#include <osg/Texture2D>
#include <osg/ShapeDrawable>
#include <osg/MatrixTransform>
#include <osg/Geometry>

#include <osgGA/TrackballManipulator>
#include <osgGA/FlightManipulator>
#include <osgGA/DriveManipulator>
#include <osgGA/KeySwitchMatrixManipulator>
#include <osgGA/AnimationPathManipulator>
#include <osgGA/TerrainManipulator>
#include <osgGA/AnimationPathManipulator>
#include <osgGA/StateSetManipulator>

#include <osgViewer/Viewer>
#include <osgViewer/ViewerEventHandlers>

#include <osgShadow/ShadowedScene>
#include <osgShadow/ShadowVolume>
#include <osgShadow/ShadowTexture>
#include <osgShadow/ShadowMap>
#include <osgShadow/SoftShadowMap>
#include <osgShadow/ParallelSplitShadowMap>
#include <osgShadow/LightSpacePerspectiveShadowMap>
#include <osgShadow/StandardShadowMap>

#include <osgDB/ReadFile>
#include <osgDB/WriteFile>

#include <osg/io_utils>
#include <iostream>


// for the grid data..
#include "terrain_coords.h"
// for the model number four - island scene
#include "IslandScene.h"


class ChangeFOVHandler : public osgGA::GUIEventHandler
{
public:
    ChangeFOVHandler(osg::Camera* camera)
        : _camera(camera)
    {
        double fovy, aspectRatio, zNear, zFar;
        _camera->getProjectionMatrix().getPerspective(fovy, aspectRatio, zNear, zFar);
        std::cout << "FOV is " << fovy << std::endl;
    }

    /** Deprecated, Handle events, return true if handled, false otherwise. */
    virtual bool handle(const osgGA::GUIEventAdapter& ea, osgGA::GUIActionAdapter& aa)
    {
        if (ea.getEventType() == osgGA::GUIEventAdapter::KEYUP)
        {
            if (ea.getKey() == '-' || ea.getKey() == '=' || ea.getKey() == '0')
            {
                double fovy, aspectRatio, zNear, zFar;
                _camera->getProjectionMatrix().getPerspective(fovy, aspectRatio, zNear, zFar);

                if (ea.getKey() == '-')
                {
                    fovy -= 5.0;
                }

                if (ea.getKey() == '=')
                {
                    fovy += 5.0;
                }

                if (ea.getKey() == '0')
                {
                    fovy = 45.0;
                }

                std::cout << "Setting FOV to " << fovy << std::endl;
                _camera->getProjectionMatrix().makePerspective(fovy, aspectRatio, zNear, zFar);

                return true;
            }
        }

        return false;
    }

    osg::ref_ptr<osg::Camera> _camera;
};


class DumpShadowVolumesHandler : public osgGA::GUIEventHandler
{
public:
    DumpShadowVolumesHandler(  )
    {
        set( false );
    }

    bool get() { return _value; } 
    void set( bool value ) { _value = value; } 

    /** Deprecated, Handle events, return true if handled, false otherwise. */
    virtual bool handle(const osgGA::GUIEventAdapter& ea, osgGA::GUIActionAdapter& aa)
    {
        if (ea.getEventType() == osgGA::GUIEventAdapter::KEYUP)
        {
            if (ea.getKey() == 'D' )
            {
                set( true );
                return true;
            }
        }

        return false;
    }

    bool  _value;
};


static int ReceivesShadowTraversalMask = 0x1;
static int CastsShadowTraversalMask = 0x2;

namespace ModelOne
{

    enum Faces
    {
        FRONT_FACE = 1,
        BACK_FACE = 2,
        LEFT_FACE = 4,
        RIGHT_FACE = 8,
        TOP_FACE = 16,
        BOTTOM_FACE = 32
    };

    osg::Node* createCube(unsigned int mask)
    {
        osg::Geode* geode = new osg::Geode;

        osg::Geometry* geometry = new osg::Geometry;
        geode->addDrawable(geometry);

        osg::Vec3Array* vertices = new osg::Vec3Array;
        geometry->setVertexArray(vertices);

        osg::Vec3Array* normals = new osg::Vec3Array;
        geometry->setNormalArray(normals);
        geometry->setNormalBinding(osg::Geometry::BIND_PER_VERTEX);

        osg::Vec4Array* colours = new osg::Vec4Array;
        geometry->setColorArray(colours);
        geometry->setColorBinding(osg::Geometry::BIND_OVERALL);
        colours->push_back(osg::Vec4(1.0f,1.0f,1.0f,1.0f));


        osg::Vec3 origin(0.0f,0.0f,0.0f);
        osg::Vec3 dx(2.0f,0.0f,0.0f);
        osg::Vec3 dy(0.0f,1.0f,0.0f);
        osg::Vec3 dz(0.0f,0.0f,1.0f);

        osg::Vec3 px(1.0f,0.0,0.0f);
        osg::Vec3 nx(-1.0f,0.0,0.0f);
        osg::Vec3 py(0.0f,1.0f,0.0f);
        osg::Vec3 ny(0.0f,-1.0f,0.0f);
        osg::Vec3 pz(0.0f,0.0f,1.0f);
        osg::Vec3 nz(0.0f,0.0f,-1.0f);

        if (mask & FRONT_FACE)
        {
            // front face
            vertices->push_back(origin);
            vertices->push_back(origin+dx);
            vertices->push_back(origin+dx+dz);
            vertices->push_back(origin+dz);
            normals->push_back(ny);
            normals->push_back(ny);
            normals->push_back(ny);
            normals->push_back(ny);
        }

        if (mask & BACK_FACE)
        {
            // back face
            vertices->push_back(origin+dy);
            vertices->push_back(origin+dy+dz);
            vertices->push_back(origin+dy+dx+dz);
            vertices->push_back(origin+dy+dx);
            normals->push_back(py);
            normals->push_back(py);
            normals->push_back(py);
            normals->push_back(py);
        }

        if (mask & LEFT_FACE)
        {
            // left face
            vertices->push_back(origin+dy);
            vertices->push_back(origin);
            vertices->push_back(origin+dz);
            vertices->push_back(origin+dy+dz);
            normals->push_back(nx);
            normals->push_back(nx);
            normals->push_back(nx);
            normals->push_back(nx);
        }

        if (mask & RIGHT_FACE)
        {
            // right face
            vertices->push_back(origin+dx+dy);
            vertices->push_back(origin+dx+dy+dz);
            vertices->push_back(origin+dx+dz);
            vertices->push_back(origin+dx);
            normals->push_back(px);
            normals->push_back(px);
            normals->push_back(px);
            normals->push_back(px);
        }

        if (mask & TOP_FACE)
        {
            // top face
            vertices->push_back(origin+dz);
            vertices->push_back(origin+dz+dx);
            vertices->push_back(origin+dz+dx+dy);
            vertices->push_back(origin+dz+dy);
            normals->push_back(pz);
            normals->push_back(pz);
            normals->push_back(pz);
            normals->push_back(pz);
        }

        if (mask & BOTTOM_FACE)
        {
            // bottom face
            vertices->push_back(origin);
            vertices->push_back(origin+dy);
            vertices->push_back(origin+dx+dy);
            vertices->push_back(origin+dx);
            normals->push_back(nz);
            normals->push_back(nz);
            normals->push_back(nz);
            normals->push_back(nz);
        }

        geometry->addPrimitiveSet(new osg::DrawArrays(GL_QUADS, 0, vertices->size()));

        return geode;
    }

    class SwitchHandler : public osgGA::GUIEventHandler
    {
    public:

        SwitchHandler():
            _childNum(0) {}

        virtual bool handle(const osgGA::GUIEventAdapter& ea,osgGA::GUIActionAdapter& /*aa*/, osg::Object* object, osg::NodeVisitor* /*nv*/)
        {
            osg::Switch* sw = dynamic_cast<osg::Switch*>(object);
            if (!sw) return false;

            if (ea.getHandled()) return false;

            switch(ea.getEventType())
            {
                case(osgGA::GUIEventAdapter::KEYDOWN):
                {
                    if (ea.getKey()=='n')
                    {
                        ++_childNum;
                        if (_childNum >= sw->getNumChildren()) _childNum = 0;

                        sw->setSingleChildOn(_childNum);
                        return true;
                    }
                    break;
                }
                default:
                    break;
            }
            return false;
        }

    protected:

        virtual ~SwitchHandler() {}
        unsigned int    _childNum;

    };


    osg::Node* createModel(osg::ArgumentParser& /*arguments*/)
    {
        osg::Switch* sw = new osg::Switch;
        sw->setEventCallback(new ModelOne::SwitchHandler);

        sw->addChild(ModelOne::createCube(ModelOne::FRONT_FACE), true);
        sw->addChild(ModelOne::createCube(ModelOne::FRONT_FACE | ModelOne::BACK_FACE), false);
        sw->addChild(ModelOne::createCube(ModelOne::FRONT_FACE | ModelOne::BACK_FACE | ModelOne::LEFT_FACE), false);
        sw->addChild(ModelOne::createCube(ModelOne::FRONT_FACE | ModelOne::BACK_FACE | ModelOne::LEFT_FACE | ModelOne::RIGHT_FACE), false);
        sw->addChild(ModelOne::createCube(ModelOne::FRONT_FACE | ModelOne::BACK_FACE | ModelOne::LEFT_FACE | ModelOne::RIGHT_FACE | ModelOne::TOP_FACE), false);
        sw->addChild(ModelOne::createCube(ModelOne::FRONT_FACE | ModelOne::BACK_FACE | ModelOne::LEFT_FACE | ModelOne::RIGHT_FACE | ModelOne::TOP_FACE | ModelOne::BOTTOM_FACE), false);

        return sw;
    }
}

namespace ModelTwo
{
    osg::AnimationPath* createAnimationPath(const osg::Vec3& center,float radius,double looptime)
    {
        // set up the animation path
        osg::AnimationPath* animationPath = new osg::AnimationPath;
        animationPath->setLoopMode(osg::AnimationPath::LOOP);

        int numSamples = 40;
        float yaw = 0.0f;
        float yaw_delta = 2.0f*osg::PI/((float)numSamples-1.0f);
        float roll = osg::inDegrees(30.0f);

        double time=0.0f;
        double time_delta = looptime/(double)numSamples;
        for(int i=0;i<numSamples;++i)
        {
            osg::Vec3 position(center+osg::Vec3(sinf(yaw)*radius,cosf(yaw)*radius,0.0f));
            osg::Quat rotation(osg::Quat(roll,osg::Vec3(0.0,1.0,0.0))*osg::Quat(-(yaw+osg::inDegrees(90.0f)),osg::Vec3(0.0,0.0,1.0)));

            animationPath->insert(time,osg::AnimationPath::ControlPoint(position,rotation));

            yaw += yaw_delta;
            time += time_delta;

        }
        return animationPath;
    }

    osg::Node* createBase(const osg::Vec3& center,float radius)
    {

        osg::Geode* geode = new osg::Geode;

        // set up the texture of the base.
        osg::StateSet* stateset = new osg::StateSet();
        osg::Image* image = osgDB::readImageFile("Images/lz.rgb");
        if (image)
        {
            osg::Texture2D* texture = new osg::Texture2D;
            texture->setImage(image);
            stateset->setTextureAttributeAndModes(0,texture,osg::StateAttribute::ON);
        }

        geode->setStateSet( stateset );


        osg::HeightField* grid = new osg::HeightField;
        grid->allocate(38,39);
        grid->setOrigin(center+osg::Vec3(-radius,-radius,0.0f));
        grid->setXInterval(radius*2.0f/(float)(38-1));
        grid->setYInterval(radius*2.0f/(float)(39-1));

        float minHeight = FLT_MAX;
        float maxHeight = -FLT_MAX;


        unsigned int r;
        for(r=0;r<39;++r)
        {
            for(unsigned int c=0;c<38;++c)
            {
                float h = vertex[r+c*39][2];
                if (h>maxHeight) maxHeight=h;
                if (h<minHeight) minHeight=h;
            }
        }

        float hieghtScale = radius*0.5f/(maxHeight-minHeight);
        float hieghtOffset = -(minHeight+maxHeight)*0.5f;

        for(r=0;r<39;++r)
        {
            for(unsigned int c=0;c<38;++c)
            {
                float h = vertex[r+c*39][2];
                grid->setHeight(c,r,(h+hieghtOffset)*hieghtScale);
            }
        }

        geode->addDrawable(new osg::ShapeDrawable(grid));

        osg::Group* group = new osg::Group;
        group->addChild(geode);

        return group;

    }

    osg::Node* createMovingModel(const osg::Vec3& center, float radius)
    {
        float animationLength = 10.0f;

        osg::AnimationPath* animationPath = createAnimationPath(center,radius,animationLength);

        osg::Group* model = new osg::Group;

        osg::Node* cessna = osgDB::readNodeFile("cessna.osgt");
        if (cessna)
        {
            const osg::BoundingSphere& bs = cessna->getBound();

            float size = radius/bs.radius()*0.3f;
            osg::MatrixTransform* positioned = new osg::MatrixTransform;
            positioned->setDataVariance(osg::Object::STATIC);
            positioned->setMatrix(osg::Matrix::translate(-bs.center())*
                                  osg::Matrix::scale(size,size,size)*
                                  osg::Matrix::rotate(osg::inDegrees(180.0f),0.0f,0.0f,2.0f));

            positioned->addChild(cessna);

            osg::MatrixTransform* xform = new osg::MatrixTransform;
            xform->setUpdateCallback(new osg::AnimationPathCallback(animationPath,0.0f,2.0));
            xform->addChild(positioned);

            model->addChild(xform);
        }

        return model;
    }

    osg::Node* createModel(osg::ArgumentParser& /*arguments*/)
    {
        osg::Vec3 center(0.0f,0.0f,0.0f);
        float radius = 100.0f;
        osg::Vec3 lightPosition(center+osg::Vec3(0.0f,0.0f,radius));

        // the shadower model
        osg::Node* shadower = createMovingModel(center,radius*0.5f);
        shadower->setNodeMask(CastsShadowTraversalMask);

        // the shadowed model
        osg::Node* shadowed = createBase(center-osg::Vec3(0.0f,0.0f,radius*0.25),radius);
        shadowed->setNodeMask(ReceivesShadowTraversalMask);

        osg::Group* group = new osg::Group;

        group->addChild(shadowed);
        group->addChild(shadower);

        return group;
    }
}

namespace ModelThree
{
    osg::Group* createModel(osg::ArgumentParser& arguments)
    {
        osg::Group* scene = new osg::Group;

        osg::ref_ptr<osg::Geode> geode_1 = new osg::Geode;
        scene->addChild(geode_1.get());

        osg::ref_ptr<osg::Geode> geode_2 = new osg::Geode;
        osg::ref_ptr<osg::MatrixTransform> transform_2 = new osg::MatrixTransform;
        transform_2->addChild(geode_2.get());
//        transform_2->setUpdateCallback(new osg::AnimationPathCallback(osg::Vec3(0, 0, 0), osg::Z_AXIS, osg::inDegrees(45.0f)));
        scene->addChild(transform_2.get());

        osg::ref_ptr<osg::Geode> geode_3 = new osg::Geode;
        osg::ref_ptr<osg::MatrixTransform> transform_3 = new osg::MatrixTransform;
        transform_3->addChild(geode_3.get());
//        transform_3->setUpdateCallback(new osg::AnimationPathCallback(osg::Vec3(0, 0, 0), osg::Z_AXIS, osg::inDegrees(-22.5f)));
        scene->addChild(transform_3.get());

        const float radius = 0.8f;
        const float height = 1.0f;
        osg::ref_ptr<osg::TessellationHints> hints = new osg::TessellationHints;
        hints->setDetailRatio(2.0f);
        osg::ref_ptr<osg::ShapeDrawable> shape;

        shape = new osg::ShapeDrawable(new osg::Box(osg::Vec3(0.0f, 0.0f, -2.0f), 10, 10.0f, 0.1f), hints.get());
        shape->setColor(osg::Vec4(0.5f, 0.5f, 0.7f, 1.0f));
        geode_1->addDrawable(shape.get());

        shape = new osg::ShapeDrawable(new osg::Sphere(osg::Vec3(0.0f, 0.0f, 0.0f), radius * 2), hints.get());
        shape->setColor(osg::Vec4(0.8f, 0.8f, 0.8f, 1.0f));
        geode_1->addDrawable(shape.get());

        shape = new osg::ShapeDrawable(new osg::Sphere(osg::Vec3(-3.0f, 0.0f, 0.0f), radius), hints.get());
        shape->setColor(osg::Vec4(0.6f, 0.8f, 0.8f, 1.0f));
        geode_2->addDrawable(shape.get());

        shape = new osg::ShapeDrawable(new osg::Box(osg::Vec3(3.0f, 0.0f, 0.0f), 2 * radius), hints.get());
        shape->setColor(osg::Vec4(0.4f, 0.9f, 0.3f, 1.0f));
        geode_2->addDrawable(shape.get());

        shape = new osg::ShapeDrawable(new osg::Cone(osg::Vec3(0.0f, -3.0f, 0.0f), radius, height), hints.get());
        shape->setColor(osg::Vec4(0.2f, 0.5f, 0.7f, 1.0f));
        geode_2->addDrawable(shape.get());

        shape = new osg::ShapeDrawable(new osg::Cylinder(osg::Vec3(0.0f, 3.0f, 0.0f), radius, height), hints.get());
        shape->setColor(osg::Vec4(1.0f, 0.3f, 0.3f, 1.0f));
        geode_2->addDrawable(shape.get());

        shape = new osg::ShapeDrawable(new osg::Box(osg::Vec3(0.0f, 0.0f, 3.0f), 2.0f, 2.0f, 0.1f), hints.get());
        shape->setColor(osg::Vec4(0.8f, 0.8f, 0.4f, 1.0f));
        geode_3->addDrawable(shape.get());

        // material
        osg::ref_ptr<osg::Material> matirial = new osg::Material;
        matirial->setColorMode(osg::Material::DIFFUSE);
        matirial->setAmbient(osg::Material::FRONT_AND_BACK, osg::Vec4(0, 0, 0, 1));
        matirial->setSpecular(osg::Material::FRONT_AND_BACK, osg::Vec4(1, 1, 1, 1));
        matirial->setShininess(osg::Material::FRONT_AND_BACK, 64.0f);
        scene->getOrCreateStateSet()->setAttributeAndModes(matirial.get(), osg::StateAttribute::ON);

        bool withBaseTexture = true;
        while(arguments.read("--with-base-texture")) { withBaseTexture = true; }
        while(arguments.read("--no-base-texture")) { withBaseTexture = false; }

        if (withBaseTexture)
        {
            scene->getOrCreateStateSet()->setTextureAttributeAndModes( 0, new osg::Texture2D(osgDB::readImageFile("Images/lz.rgb")), osg::StateAttribute::ON);
        }

        return scene;
    }

}


osg::Node* createTestModel(osg::ArgumentParser& arguments)
{
    if (arguments.read("-1"))
    {
        return ModelOne::createModel(arguments);
    }
    else if (arguments.read("-2"))
    {
        return ModelTwo::createModel(arguments);
    }
    else if (arguments.read("-4"))
    {
        return ModelFour::createModel(arguments);
    }
    else /*if (arguments.read("-3"))*/
    {
        return ModelThree::createModel(arguments);
    }

}


int main(int argc, char** argv)
{
    // use an ArgumentParser object to manage the program arguments.
    osg::ArgumentParser arguments(&argc, argv);

    // set up the usage document, in case we need to print out how to use this program.
    arguments.getApplicationUsage()->setDescription(arguments.getApplicationName() + " is the example which demonstrates using of GL_ARB_shadow extension implemented in osg::Texture class");
    arguments.getApplicationUsage()->setCommandLineUsage(arguments.getApplicationName());
    arguments.getApplicationUsage()->addCommandLineOption("-h or --help", "Display this information");
    arguments.getApplicationUsage()->addCommandLineOption("--positionalLight", "Use a positional light.");
    arguments.getApplicationUsage()->addCommandLineOption("--directionalLight", "Use a direction light.");
    arguments.getApplicationUsage()->addCommandLineOption("--noUpdate", "Disable the updating the of light source.");

    arguments.getApplicationUsage()->addCommandLineOption("--castsShadowMask", "Override default castsShadowMask (default - 0x2)");
    arguments.getApplicationUsage()->addCommandLineOption("--receivesShadowMask", "Override default receivesShadowMask (default - 0x1)");

    arguments.getApplicationUsage()->addCommandLineOption("--base", "Add a base geometry to test shadows.");
    arguments.getApplicationUsage()->addCommandLineOption("--sv", "Select ShadowVolume implementation.");
    arguments.getApplicationUsage()->addCommandLineOption("--ssm", "Select SoftShadowMap implementation.");
    arguments.getApplicationUsage()->addCommandLineOption("--sm", "Select ShadowMap implementation.");

    arguments.getApplicationUsage()->addCommandLineOption("--pssm", "Select ParallelSplitShadowMap implementation.");//ADEGLI
    arguments.getApplicationUsage()->addCommandLineOption("--mapcount", "ParallelSplitShadowMap texture count.");//ADEGLI
    arguments.getApplicationUsage()->addCommandLineOption("--mapres", "ParallelSplitShadowMap texture resolution.");//ADEGLI
    arguments.getApplicationUsage()->addCommandLineOption("--debug-color", "ParallelSplitShadowMap display debugging color (only the first 3 maps are color r=0,g=1,b=2.");//ADEGLI
    arguments.getApplicationUsage()->addCommandLineOption("--minNearSplit", "ParallelSplitShadowMap shadow map near offset.");//ADEGLI
    arguments.getApplicationUsage()->addCommandLineOption("--maxFarDist", "ParallelSplitShadowMap max far distance to shadow.");//ADEGLI
    arguments.getApplicationUsage()->addCommandLineOption("--moveVCamFactor", "ParallelSplitShadowMap move the virtual frustum behind the real camera, (also back ground object can cast shadow).");//ADEGLI
    arguments.getApplicationUsage()->addCommandLineOption("--PolyOffset-Factor", "ParallelSplitShadowMap set PolygonOffset factor.");//ADEGLI
    arguments.getApplicationUsage()->addCommandLineOption("--PolyOffset-Unit", "ParallelSplitShadowMap set PolygonOffset unit.");//ADEGLI

    arguments.getApplicationUsage()->addCommandLineOption("--lispsm", "Select LightSpacePerspectiveShadowMap implementation.");
    arguments.getApplicationUsage()->addCommandLineOption("--msm", "Select MinimalShadowMap implementation.");
    arguments.getApplicationUsage()->addCommandLineOption("--ViewBounds", "MSM, LiSPSM optimize shadow for view frustum (weakest option)");
    arguments.getApplicationUsage()->addCommandLineOption("--CullBounds", "MSM, LiSPSM optimize shadow for bounds of culled objects in view frustum (better option).");
    arguments.getApplicationUsage()->addCommandLineOption("--DrawBounds", "MSM, LiSPSM optimize shadow for bounds of predrawn pixels in view frustum (best & default).");
    arguments.getApplicationUsage()->addCommandLineOption("--mapres", "MSM, LiSPSM & texture resolution.");
    arguments.getApplicationUsage()->addCommandLineOption("--maxFarDist", "MSM, LiSPSM max far distance to shadow.");
    arguments.getApplicationUsage()->addCommandLineOption("--moveVCamFactor", "MSM, LiSPSM move the virtual frustum behind the real camera, (also back ground object can cast shadow).");
    arguments.getApplicationUsage()->addCommandLineOption("--minLightMargin", "MSM, LiSPSM the same as --moveVCamFactor.");

    arguments.getApplicationUsage()->addCommandLineOption("-1", "Use test model one.");
    arguments.getApplicationUsage()->addCommandLineOption("-2", "Use test model two.");
    arguments.getApplicationUsage()->addCommandLineOption("-3", "Use test model three (default).");
    arguments.getApplicationUsage()->addCommandLineOption("-4", "Use test model four - island scene.");
    arguments.getApplicationUsage()->addCommandLineOption("--two-sided", "Use two-sided stencil extension for shadow volumes.");
    arguments.getApplicationUsage()->addCommandLineOption("--two-pass", "Use two-pass stencil for shadow volumes.");

    // construct the viewer.
    osgViewer::Viewer viewer(arguments);

    // if user request help write it out to cout.
    if (arguments.read("-h") || arguments.read("--help"))
    {
        arguments.getApplicationUsage()->write(std::cout);
        return 1;
    }

    double zNear=1.0, zMid=10.0, zFar=1000.0;
    if (arguments.read("--depth-partition",zNear, zMid, zFar))
    {
        // set up depth partitioning
        osg::ref_ptr<osgViewer::DepthPartitionSettings> dps = new osgViewer::DepthPartitionSettings;
        dps->_mode = osgViewer::DepthPartitionSettings::FIXED_RANGE;
        dps->_zNear = zNear;
        dps->_zMid = zMid;
        dps->_zFar = zFar;
        viewer.setUpDepthPartition(dps.get());
    }

    if (arguments.read("--dp"))
    {
        // set up depth partitioning
        viewer.setUpDepthPartition();
    }

    float fov = 0.0;
    while (arguments.read("--fov",fov)) {}

    osg::Vec4 lightpos(0.0,0.0,1,0.0);
    while (arguments.read("--positionalLight")) { lightpos.set(0.5,0.5,1.5,1.0); }
    while (arguments.read("--directionalLight")) { lightpos.set(0.0,0.0,1,0.0); }

    while ( arguments.read("--light-pos", lightpos.x(), lightpos.y(), lightpos.z(), lightpos.w())) {}
    while ( arguments.read("--light-pos", lightpos.x(), lightpos.y(), lightpos.z())) { lightpos.w()=1.0; }
    while ( arguments.read("--light-dir", lightpos.x(), lightpos.y(), lightpos.z())) { lightpos.w()=0.0; }


    while (arguments.read("--castsShadowMask", CastsShadowTraversalMask ));
    while (arguments.read("--receivesShadowMask", ReceivesShadowTraversalMask ));

    bool updateLightPosition = true;
    while (arguments.read("--noUpdate")) updateLightPosition = false;

    // set up the camera manipulators.
    {
        osg::ref_ptr<osgGA::KeySwitchMatrixManipulator> keyswitchManipulator = new osgGA::KeySwitchMatrixManipulator;

        keyswitchManipulator->addMatrixManipulator( '1', "Trackball", new osgGA::TrackballManipulator() );
        keyswitchManipulator->addMatrixManipulator( '2', "Flight", new osgGA::FlightManipulator() );
        keyswitchManipulator->addMatrixManipulator( '3', "Drive", new osgGA::DriveManipulator() );
        keyswitchManipulator->addMatrixManipulator( '4', "Terrain", new osgGA::TerrainManipulator() );

        std::string pathfile;
        char keyForAnimationPath = '5';
        while (arguments.read("-p",pathfile))
        {
            osgGA::AnimationPathManipulator* apm = new osgGA::AnimationPathManipulator(pathfile);
            if (apm || !apm->valid())
            {
                unsigned int num = keyswitchManipulator->getNumMatrixManipulators();
                keyswitchManipulator->addMatrixManipulator( keyForAnimationPath, "Path", apm );
                keyswitchManipulator->selectMatrixManipulator(num);
                ++keyForAnimationPath;
            }
        }

        viewer.setCameraManipulator( keyswitchManipulator.get() );
    }

    // add the state manipulator
    viewer.addEventHandler( new osgGA::StateSetManipulator(viewer.getCamera()->getOrCreateStateSet()) );

    // add stats
    viewer.addEventHandler( new osgViewer::StatsHandler() );

    // add the record camera path handler
    viewer.addEventHandler(new osgViewer::RecordCameraPathHandler);

    // add the window size toggle handler
    viewer.addEventHandler(new osgViewer::WindowSizeHandler);

    // add the threading handler
    viewer.addEventHandler( new osgViewer::ThreadingHandler() );

    osg::ref_ptr<osgShadow::ShadowedScene> shadowedScene = new osgShadow::ShadowedScene;

    shadowedScene->setReceivesShadowTraversalMask(ReceivesShadowTraversalMask);
    shadowedScene->setCastsShadowTraversalMask(CastsShadowTraversalMask);

    osg::ref_ptr<osgShadow::MinimalShadowMap> msm = NULL;
    if (arguments.read("--no-shadows"))
    {
        OSG_NOTICE<<"Not using a ShadowTechnique"<<std::endl;
        shadowedScene->setShadowTechnique(0);
    }
    else if (arguments.read("--sv"))
    {
        // hint to tell viewer to request stencil buffer when setting up windows
        osg::DisplaySettings::instance()->setMinimumNumStencilBits(8);

        osg::ref_ptr<osgShadow::ShadowVolume> sv = new osgShadow::ShadowVolume;
        sv->setDynamicShadowVolumes(updateLightPosition);
        while (arguments.read("--two-sided")) sv->setDrawMode(osgShadow::ShadowVolumeGeometry::STENCIL_TWO_SIDED);
        while (arguments.read("--two-pass")) sv->setDrawMode(osgShadow::ShadowVolumeGeometry::STENCIL_TWO_PASS);

        shadowedScene->setShadowTechnique(sv.get());
    }
    else if (arguments.read("--st"))
    {
        osg::ref_ptr<osgShadow::ShadowTexture> st = new osgShadow::ShadowTexture;
        shadowedScene->setShadowTechnique(st.get());
    }
    else if (arguments.read("--stsm"))
    {
        osg::ref_ptr<osgShadow::StandardShadowMap> st = new osgShadow::StandardShadowMap;
        shadowedScene->setShadowTechnique(st.get());
    }
    else if (arguments.read("--pssm"))
    {
        int mapcount = 3;
        while (arguments.read("--mapcount", mapcount));
        osg::ref_ptr<osgShadow::ParallelSplitShadowMap> pssm = new osgShadow::ParallelSplitShadowMap(NULL,mapcount);

        int mapres = 1024;
        while (arguments.read("--mapres", mapres))
            pssm->setTextureResolution(mapres);

        while (arguments.read("--debug-color")) { pssm->setDebugColorOn(); }


        int minNearSplit=0;
        while (arguments.read("--minNearSplit", minNearSplit))
            if ( minNearSplit > 0 ) {
                pssm->setMinNearDistanceForSplits(minNearSplit);
                std::cout << "ParallelSplitShadowMap : setMinNearDistanceForSplits(" << minNearSplit <<")" << std::endl;
            }

        int maxfardist = 0;
        while (arguments.read("--maxFarDist", maxfardist))
            if ( maxfardist > 0 ) {
                pssm->setMaxFarDistance(maxfardist);
                std::cout << "ParallelSplitShadowMap : setMaxFarDistance(" << maxfardist<<")" << std::endl;
            }

        int moveVCamFactor = 0;
        while (arguments.read("--moveVCamFactor", moveVCamFactor))
            if ( maxfardist > 0 ) {
                pssm->setMoveVCamBehindRCamFactor(moveVCamFactor);
                std::cout << "ParallelSplitShadowMap : setMoveVCamBehindRCamFactor(" << moveVCamFactor<<")" << std::endl;
            }


        
        double polyoffsetfactor = pssm->getPolygonOffset().x();
        double polyoffsetunit   = pssm->getPolygonOffset().y();
        while (arguments.read("--PolyOffset-Factor", polyoffsetfactor));
        while (arguments.read("--PolyOffset-Unit", polyoffsetunit));
        pssm->setPolygonOffset(osg::Vec2(polyoffsetfactor,polyoffsetunit)); 

        shadowedScene->setShadowTechnique(pssm.get());
    }
    else if (arguments.read("--ssm"))
    {
        osg::ref_ptr<osgShadow::SoftShadowMap> sm = new osgShadow::SoftShadowMap;
        shadowedScene->setShadowTechnique(sm.get());
    }
    else if ( arguments.read("--lispsm") ) 
    {
        if( arguments.read( "--ViewBounds" ) )
            msm = new osgShadow::LightSpacePerspectiveShadowMapVB;
        else if( arguments.read( "--CullBounds" ) )
            msm = new osgShadow::LightSpacePerspectiveShadowMapCB;
        else // if( arguments.read( "--DrawBounds" ) ) // default
            msm = new osgShadow::LightSpacePerspectiveShadowMapDB;
    } 
    else if( arguments.read("--msm") )
    {
       if( arguments.read( "--ViewBounds" ) )
            msm = new osgShadow::MinimalShadowMap;
       else if( arguments.read( "--CullBounds" ) )
            msm = new osgShadow::MinimalCullBoundsShadowMap;
       else // if( arguments.read( "--DrawBounds" ) ) // default
            msm = new osgShadow::MinimalDrawBoundsShadowMap;
    }
    else /* if (arguments.read("--sm")) */
    {
        osg::ref_ptr<osgShadow::ShadowMap> sm = new osgShadow::ShadowMap;
        shadowedScene->setShadowTechnique(sm.get());

        int mapres = 1024;
        while (arguments.read("--mapres", mapres))
            sm->setTextureSize(osg::Vec2s(mapres,mapres));
    }

    if( msm )// Set common MSM & LISPSM arguments
    {
        shadowedScene->setShadowTechnique( msm.get() );
        while( arguments.read("--debugHUD") )           
            msm->setDebugDraw( true );

        float minLightMargin = 10.f;
        float maxFarPlane = 0;
        unsigned int texSize = 1024;
        unsigned int baseTexUnit = 0;
        unsigned int shadowTexUnit = 1;

        while ( arguments.read("--moveVCamFactor", minLightMargin ) );
        while ( arguments.read("--minLightMargin", minLightMargin ) );
        while ( arguments.read("--maxFarDist", maxFarPlane ) );
        while ( arguments.read("--mapres", texSize ));
        while ( arguments.read("--baseTextureUnit", baseTexUnit) );
        while ( arguments.read("--shadowTextureUnit", shadowTexUnit) );

        msm->setMinLightMargin( minLightMargin );
        msm->setMaxFarPlane( maxFarPlane );
        msm->setTextureSize( osg::Vec2s( texSize, texSize ) );
        msm->setShadowTextureCoordIndex( shadowTexUnit );
        msm->setShadowTextureUnit( shadowTexUnit );
        msm->setBaseTextureCoordIndex( baseTexUnit );
        msm->setBaseTextureUnit( baseTexUnit );
    }

    OSG_NOTICE<<"shadowedScene->getShadowTechnique()="<<shadowedScene->getShadowTechnique()<<std::endl;

    osg::ref_ptr<osg::Node> model = osgDB::readNodeFiles(arguments);
    if (model.valid())
    {
        model->setNodeMask(CastsShadowTraversalMask | ReceivesShadowTraversalMask);
    }
    else
    {
        model = createTestModel(arguments);
    }

    // get the bounds of the model.
    osg::ComputeBoundsVisitor cbbv;
    model->accept(cbbv);
    osg::BoundingBox bb = cbbv.getBoundingBox();

    if (lightpos.w()==1.0)
    {
        lightpos.x() = bb.xMin()+(bb.xMax()-bb.xMin())*lightpos.x();
        lightpos.y() = bb.yMin()+(bb.yMax()-bb.yMin())*lightpos.y();
        lightpos.z() = bb.zMin()+(bb.zMax()-bb.zMin())*lightpos.z();
    }
      
    if ( arguments.read("--base"))
    {

        osg::Geode* geode = new osg::Geode;

        osg::Vec3 widthVec(bb.radius(), 0.0f, 0.0f);
        osg::Vec3 depthVec(0.0f, bb.radius(), 0.0f);
        osg::Vec3 centerBase( (bb.xMin()+bb.xMax())*0.5f, (bb.yMin()+bb.yMax())*0.5f, bb.zMin()-bb.radius()*0.1f );

        geode->addDrawable( osg::createTexturedQuadGeometry( centerBase-widthVec*1.5f-depthVec*1.5f,
                                                             widthVec*3.0f, depthVec*3.0f) );

        geode->setNodeMask(shadowedScene->getReceivesShadowTraversalMask());

        geode->getOrCreateStateSet()->setTextureAttributeAndModes(0, new osg::Texture2D(osgDB::readImageFile("Images/lz.rgb")));

        shadowedScene->addChild(geode);
    }

    osg::ref_ptr<osg::LightSource> ls = new osg::LightSource;
    ls->getLight()->setPosition(lightpos);

    bool spotlight = false;
    if (arguments.read("--spotLight"))
    {
        spotlight = true;

        osg::Vec3 center = bb.center();
        osg::Vec3 lightdir = center - osg::Vec3(lightpos.x(), lightpos.y(), lightpos.z());
        lightdir.normalize();
        ls->getLight()->setDirection(lightdir);
        ls->getLight()->setSpotCutoff(25.0f);

        //set the LightSource, only for checking, there is only 1 light in the scene
        osgShadow::ShadowMap* shadowMap = dynamic_cast<osgShadow::ShadowMap*>(shadowedScene->getShadowTechnique());
        if( shadowMap ) shadowMap->setLight(ls.get());
    }

    if ( arguments.read("--coloured-light"))
    {
        ls->getLight()->setAmbient(osg::Vec4(1.0,0.0,0.0,1.0));
        ls->getLight()->setDiffuse(osg::Vec4(0.0,1.0,0.0,1.0));
    }
    else
    {
        ls->getLight()->setAmbient(osg::Vec4(0.2,0.2,0.2,1.0));
        ls->getLight()->setDiffuse(osg::Vec4(0.8,0.8,0.8,1.0));
    }

    shadowedScene->addChild(model.get());
    shadowedScene->addChild(ls.get());

    viewer.setSceneData(shadowedScene.get());

    osg::ref_ptr< DumpShadowVolumesHandler > dumpShadowVolumes = new DumpShadowVolumesHandler;

    viewer.addEventHandler(new ChangeFOVHandler(viewer.getCamera()));
    viewer.addEventHandler( dumpShadowVolumes.get() );

    // create the windows and run the threads.
    viewer.realize();

    if (fov!=0.0)
    {
        double fovy, aspectRatio, zNear, zFar;
        viewer.getCamera()->getProjectionMatrix().getPerspective(fovy, aspectRatio, zNear, zFar);

        std::cout << "Setting FOV to " << fov << std::endl;
        viewer.getCamera()->getProjectionMatrix().makePerspective(fov, aspectRatio, zNear, zFar);
    }

    // it is done after viewer.realize() so that the windows are already initialized
    if ( arguments.read("--debugHUD"))
    {
        osgViewer::Viewer::Windows windows;
        viewer.getWindows(windows);

        if (windows.empty()) return 1;

        osgShadow::ShadowMap* sm = dynamic_cast<osgShadow::ShadowMap*>(shadowedScene->getShadowTechnique());
        if( sm ) { 
            osg::ref_ptr<osg::Camera> hudCamera = sm->makeDebugHUD();

            // set up cameras to rendering on the first window available.
            hudCamera->setGraphicsContext(windows[0]);
            hudCamera->setViewport(0,0,windows[0]->getTraits()->width, windows[0]->getTraits()->height);

            viewer.addSlave(hudCamera.get(), false);
        }
    }


    // osgDB::writeNodeFile(*group,"test.osgt");
 
    while (!viewer.done())
    {
        {
            osgShadow::MinimalShadowMap * msm = dynamic_cast<osgShadow::MinimalShadowMap*>( shadowedScene->getShadowTechnique() );
   
            if( msm ) {

                // If scene decorated by CoordinateSystemNode try to find localToWorld 
                // and set modellingSpaceToWorld matrix to optimize scene bounds computation

                osg::NodePath np = viewer.getCoordinateSystemNodePath();
                if( !np.empty() ) {
                    osg::CoordinateSystemNode * csn = 
                        dynamic_cast<osg::CoordinateSystemNode *>( np.back() );

                    if( csn ) {
                        osg::Vec3d pos = 
                            viewer.getCameraManipulator()->getMatrix().getTrans();

                        msm->setModellingSpaceToWorldTransform
                            ( csn->computeLocalCoordinateFrame( pos ) );
                    }
                }
            }        
        }

        if (updateLightPosition)
        {
            float t = viewer.getFrameStamp()->getSimulationTime();

            if (lightpos.w()==1.0)
            {
                lightpos.set(bb.center().x()+sinf(t)*bb.radius(), bb.center().y() + cosf(t)*bb.radius(), bb.zMax() + bb.radius()*3.0f  ,1.0f);
            }
            else
            {
                lightpos.set(sinf(t),cosf(t),1.0f,0.0f);
            }
            ls->getLight()->setPosition(lightpos);

            osg::Vec3f lightDir(-lightpos.x(),-lightpos.y(),-lightpos.z());
            if(spotlight)
                lightDir =  osg::Vec3(bb.center().x()+sinf(t)*bb.radius()/2.0, bb.center().y() + cosf(t)*bb.radius()/2.0, bb.center().z())
                - osg::Vec3(lightpos.x(), lightpos.y(), lightpos.z()) ;
            lightDir.normalize();
            ls->getLight()->setDirection(lightDir);
        }

        if( dumpShadowVolumes->get() )
        {
            dumpShadowVolumes->set( false );

            static int dumpFileNo = 0;
            dumpFileNo ++;
            char filename[256];
            std::sprintf( filename, "shadowDump%d.osgt", dumpFileNo );
            
            osgShadow::MinimalShadowMap * msm = dynamic_cast<osgShadow::MinimalShadowMap*>( shadowedScene->getShadowTechnique() );

            if( msm ) msm->setDebugDump( filename );            
        }

        viewer.frame();
    }

    return 0;
}
