#include "shadow.hpp"

#include <osgShadow/ShadowedScene>
#include <osg/CullFace>
#include <osg/Geode>
#include <osg/io_utils>
#include <osgDB/FileUtils>
#include <osgDB/ReadFile>

#include <components/settings/settings.hpp>

namespace SceneUtil
{
    using namespace osgShadow;

    std::string debugVertexShaderSource = "void main(void){gl_Position = gl_Vertex; gl_TexCoord[0]=gl_MultiTexCoord0;}";
    std::string debugFragmentShaderSource =
        "uniform sampler2D texture;                                              \n"
        "                                                                        \n"
        "void main(void)                                                         \n"
        "{                                                                       \n"
#if 1
        "    float f = texture2D( texture, gl_TexCoord[0].xy ).r;                   \n"
        "                                                                        \n"
        "    f = 256.0 * f;                                                      \n"
        "    float fC = floor( f ) / 256.0;                                      \n"
        "                                                                        \n"
        "    f = 256.0 * fract( f );                                             \n"
        "    float fS = floor( f ) / 256.0;                                      \n"
        "                                                                        \n"
        "    f = 256.0 * fract( f );                                             \n"
        "    float fH = floor( f ) / 256.0;                                      \n"
        "                                                                        \n"
        "    fS *= 0.5;                                                          \n"
        "    fH = ( fH  * 0.34 + 0.66 ) * ( 1.0 - fS );                          \n"
        "                                                                        \n"
        "    vec3 rgb = vec3( ( fC > 0.5 ? ( 1.0 - fC ) : fC ),                  \n"
        "                     abs( fC - 0.333333 ),                              \n"
        "                     abs( fC - 0.666667 ) );                            \n"
        "                                                                        \n"
        "    rgb = min( vec3( 1.0, 1.0, 1.0 ), 3.0 * rgb );                      \n"
        "                                                                        \n"
        "    float fMax = max( max( rgb.r, rgb.g ), rgb.b );                     \n"
        "    fMax = 1.0 / fMax;                                                  \n"
        "                                                                        \n"
        "    vec3 color = fMax * rgb;                                            \n"
        "                                                                        \n"
        "    gl_FragColor =  vec4( fS + fH * color, 1 );                         \n"
#else
        "    gl_FragColor = texture2D(texture, gl_TexCoord[0].xy);                  \n"
#endif
        "}                                                                       \n";

    void MWShadow::setupShadowSettings(osg::ref_ptr<osgShadow::ShadowSettings> settings, int castsShadowMask)
    {
        if (!Settings::Manager::getBool("enable shadows", "Shadows"))
            return;

        settings->setLightNum(0);
        settings->setCastsShadowTraversalMask(castsShadowMask);
        settings->setReceivesShadowTraversalMask(~0u);

        int numberOfShadowMapsPerLight = Settings::Manager::getInt("number of shadow maps", "Shadows");
        settings->setNumShadowMapsPerLight(numberOfShadowMapsPerLight);
        settings->setBaseShadowTextureUnit(8 - numberOfShadowMapsPerLight);

        settings->setMinimumShadowMapNearFarRatio(Settings::Manager::getFloat("minimum lispsm near far ratio", "Shadows"));
        if (Settings::Manager::getBool("compute tight scene bounds", "Shadows"))
            settings->setComputeNearFarModeOverride(osg::CullSettings::COMPUTE_NEAR_FAR_USING_PRIMITIVES);

        int mapres = Settings::Manager::getInt("shadow map resolution", "Shadows");
        settings->setTextureSize(osg::Vec2s(mapres, mapres));
    }

    void MWShadow::disableShadowsForStateSet(osg::ref_ptr<osg::StateSet> stateset)
    {
        int numberOfShadowMapsPerLight = Settings::Manager::getInt("number of shadow maps", "Shadows");
        int baseShadowTextureUnit = 8 - numberOfShadowMapsPerLight;
        
        osg::ref_ptr<osg::Image> fakeShadowMapImage = new osg::Image();
        fakeShadowMapImage->allocateImage(1, 1, 1, GL_DEPTH_COMPONENT, GL_FLOAT);
        *(float*)fakeShadowMapImage->data() = std::numeric_limits<float>::infinity();
        osg::ref_ptr<osg::Texture> fakeShadowMapTexture = new osg::Texture2D(fakeShadowMapImage);
        fakeShadowMapTexture->setShadowComparison(true);
        fakeShadowMapTexture->setShadowCompareFunc(osg::Texture::ShadowCompareFunc::ALWAYS);
        for (int i = baseShadowTextureUnit; i < baseShadowTextureUnit + numberOfShadowMapsPerLight; ++i)
            stateset->setTextureAttributeAndModes(i, fakeShadowMapTexture, osg::StateAttribute::ON | osg::StateAttribute::OVERRIDE | osg::StateAttribute::PROTECTED);
    }

    MWShadow::MWShadow() : enableShadows(Settings::Manager::getBool("enable shadows", "Shadows")),
        numberOfShadowMapsPerLight(Settings::Manager::getInt("number of shadow maps", "Shadows")),
        baseShadowTextureUnit(8 - numberOfShadowMapsPerLight),
        debugHud(Settings::Manager::getBool("enable debug hud", "Shadows")),
        debugProgram(new osg::Program), debugTextureUnit(0)
    {
        if (debugHud)
        {
            osg::ref_ptr<osg::Shader> vertexShader = new osg::Shader(osg::Shader::VERTEX, debugVertexShaderSource);
            debugProgram->addShader(vertexShader);
            osg::ref_ptr<osg::Shader> fragmentShader = new osg::Shader(osg::Shader::FRAGMENT, debugFragmentShaderSource);
            debugProgram->addShader(fragmentShader);

            for (int i = 0; i < numberOfShadowMapsPerLight; ++i)
            {
                std::cout << i << std::endl;

                debugCameras.push_back(new osg::Camera);
                debugCameras[i]->setViewport(200 * i, 0, 200, 200);
                debugCameras[i]->setRenderOrder(osg::Camera::POST_RENDER);
                debugCameras[i]->setClearColor(osg::Vec4(1.0, 1.0, 0.0, 1.0));

                debugGeometry.push_back(osg::createTexturedQuadGeometry(osg::Vec3(-1, -1, 0), osg::Vec3(2, 0, 0), osg::Vec3(0, 2, 0)));
                debugGeometry[i]->setCullingActive(false);
                debugCameras[i]->addChild(debugGeometry[i]);
                osg::ref_ptr<osg::StateSet> stateSet = debugGeometry[i]->getOrCreateStateSet();
                stateSet->setAttributeAndModes(debugProgram, osg::StateAttribute::ON);
                osg::ref_ptr<osg::Uniform> textureUniform = new osg::Uniform("texture", debugTextureUnit);
                //textureUniform->setType(osg::Uniform::SAMPLER_2D);
                stateSet->addUniform(textureUniform.get());
            }
        }
    }
    
    class VDSMCameraCullCallback : public osg::NodeCallback
    {
    public:

        VDSMCameraCullCallback(ViewDependentShadowMap* vdsm, osg::Polytope& polytope);

        virtual void operator()(osg::Node*, osg::NodeVisitor* nv);

        osg::RefMatrix* getProjectionMatrix() { return _projectionMatrix.get(); }
        osgUtil::RenderStage* getRenderStage() { return _renderStage.get(); }

    protected:

        ViewDependentShadowMap*                 _vdsm;
        osg::ref_ptr<osg::RefMatrix>            _projectionMatrix;
        osg::ref_ptr<osgUtil::RenderStage>      _renderStage;
        osg::Polytope                           _polytope;
    };

    VDSMCameraCullCallback::VDSMCameraCullCallback(ViewDependentShadowMap* vdsm, osg::Polytope& polytope) :
        _vdsm(vdsm),
        _polytope(polytope)
    {
    }

    void VDSMCameraCullCallback::operator()(osg::Node* node, osg::NodeVisitor* nv)
    {
        osgUtil::CullVisitor* cv = dynamic_cast<osgUtil::CullVisitor*>(nv);
        osg::Camera* camera = dynamic_cast<osg::Camera*>(node);
        OSG_INFO << "VDSMCameraCullCallback::operator()(osg::Node* " << camera << ", osg::NodeVisitor* " << cv << ")" << std::endl;

#if 1
        if (!_polytope.empty())
        {
            OSG_INFO << "Pushing custom Polytope" << std::endl;

            osg::CullingSet& cs = cv->getProjectionCullingStack().back();

            cs.setFrustum(_polytope);

            cv->pushCullingSet();
        }
#endif
        if (_vdsm->getShadowedScene())
        {
            _vdsm->getShadowedScene()->osg::Group::traverse(*nv);
        }
#if 1
        if (!_polytope.empty())
        {
            OSG_INFO << "Popping custom Polytope" << std::endl;
            cv->popCullingSet();
        }
#endif

        _renderStage = cv->getCurrentRenderBin()->getStage();

        OSG_INFO << "VDSM second : _renderStage = " << _renderStage << std::endl;

        if (cv->getComputeNearFarMode() != osg::CullSettings::DO_NOT_COMPUTE_NEAR_FAR)
        {
            // make sure that the near plane is computed correctly.
            cv->computeNearPlane();

            osg::Matrixd projection = *(cv->getProjectionMatrix());

            OSG_INFO << "RTT Projection matrix " << projection << std::endl;

            osg::Matrix::value_type left, right, bottom, top, zNear, zFar;
            osg::Matrix::value_type epsilon = 1e-6;
            if (fabs(projection(0, 3))<epsilon  && fabs(projection(1, 3))<epsilon  && fabs(projection(2, 3))<epsilon)
            {
                projection.getOrtho(left, right,
                    bottom, top,
                    zNear, zFar);

                OSG_INFO << "Ortho zNear=" << zNear << ", zFar=" << zFar << std::endl;
            }
            else
            {
                projection.getFrustum(left, right,
                    bottom, top,
                    zNear, zFar);

                OSG_INFO << "Frustum zNear=" << zNear << ", zFar=" << zFar << std::endl;
            }

            OSG_INFO << "Calculated zNear = " << cv->getCalculatedNearPlane() << ", zFar = " << cv->getCalculatedFarPlane() << std::endl;

            zNear = osg::maximum(zNear, cv->getCalculatedNearPlane());
            zFar = osg::minimum(zFar, cv->getCalculatedFarPlane());

            cv->setCalculatedNearPlane(zNear);
            cv->setCalculatedFarPlane(zFar);

            cv->clampProjectionMatrix(projection, zNear, zFar);

            //OSG_INFO<<"RTT zNear = "<<zNear<<", zFar = "<<zFar<<std::endl;
            OSG_INFO << "RTT Projection matrix after clamping " << projection << std::endl;

            camera->setProjectionMatrix(projection);

            _projectionMatrix = cv->getProjectionMatrix();
        }
    }

    MWShadow::ComputeLightSpaceBounds::ComputeLightSpaceBounds(osg::Viewport* viewport, const osg::Matrixd& projectionMatrix, osg::Matrixd& viewMatrix) :
        osg::NodeVisitor(osg::NodeVisitor::TRAVERSE_ACTIVE_CHILDREN)
    {
        setCullingMode(osg::CullSettings::VIEW_FRUSTUM_CULLING);

        pushViewport(viewport);
        pushProjectionMatrix(new osg::RefMatrix(projectionMatrix));
        pushModelViewMatrix(new osg::RefMatrix(viewMatrix), osg::Transform::ABSOLUTE_RF);
    }

    void MWShadow::ComputeLightSpaceBounds::apply(osg::Node& node)
    {
        if (isCulled(node)) return;

        // push the culling mode.
        pushCurrentMask();

        traverse(node);

        // pop the culling mode.
        popCurrentMask();
    }

    void MWShadow::ComputeLightSpaceBounds::apply(osg::Geode& node)
    {
        if (isCulled(node)) return;

        // push the culling mode.
        pushCurrentMask();

        for (unsigned int i = 0; i<node.getNumDrawables(); ++i)
        {
            if (node.getDrawable(i))
            {
                updateBound(node.getDrawable(i)->getBoundingBox());
            }
        }

        // pop the culling mode.
        popCurrentMask();
    }

    void MWShadow::ComputeLightSpaceBounds::apply(osg::Drawable& drawable)
    {
        if (isCulled(drawable)) return;

        // push the culling mode.
        pushCurrentMask();

        updateBound(drawable.getBoundingBox());

        // pop the culling mode.
        popCurrentMask();
    }

    void MWShadow::ComputeLightSpaceBounds::apply(Terrain::QuadTreeWorld & quadTreeWorld)
    {
        // For now, just expand the bounds fully as terrain will fill them up and possible ways to detect which terrain definitely won't cast shadows aren't implemented.

        update(osg::Vec3(-1.0, -1.0, 0.0));
        update(osg::Vec3(1.0, 1.0, 0.0));
    }

    void MWShadow::ComputeLightSpaceBounds::apply(osg::Billboard&)
    {
        OSG_INFO << "Warning Billboards not yet supported" << std::endl;
        return;
    }

    void MWShadow::ComputeLightSpaceBounds::apply(osg::Projection&)
    {
        // projection nodes won't affect a shadow map so their subgraphs should be ignored
        return;
    }

    void MWShadow::ComputeLightSpaceBounds::apply(osg::Transform& transform)
    {
        if (isCulled(transform)) return;

        // push the culling mode.
        pushCurrentMask();

        // absolute transforms won't affect a shadow map so their subgraphs should be ignored.
        if (transform.getReferenceFrame() == osg::Transform::RELATIVE_RF)
        {
            osg::ref_ptr<osg::RefMatrix> matrix = new osg::RefMatrix(*getModelViewMatrix());
            transform.computeLocalToWorldMatrix(*matrix, this);
            pushModelViewMatrix(matrix.get(), transform.getReferenceFrame());

            traverse(transform);

            popModelViewMatrix();
        }

        // pop the culling mode.
        popCurrentMask();

    }

    void MWShadow::ComputeLightSpaceBounds::apply(osg::Camera&)
    {
        // camera nodes won't affect a shadow map so their subgraphs should be ignored
        return;
    }

    void MWShadow::ComputeLightSpaceBounds::updateBound(const osg::BoundingBox& bb)
    {
        if (!bb.valid()) return;

        const osg::Matrix& matrix = *getModelViewMatrix() * *getProjectionMatrix();

        update(bb.corner(0) * matrix);
        update(bb.corner(1) * matrix);
        update(bb.corner(2) * matrix);
        update(bb.corner(3) * matrix);
        update(bb.corner(4) * matrix);
        update(bb.corner(5) * matrix);
        update(bb.corner(6) * matrix);
        update(bb.corner(7) * matrix);
    }

    void MWShadow::ComputeLightSpaceBounds::update(const osg::Vec3& v)
    {
        if (v.z()<-1.0f)
        {
            //OSG_NOTICE<<"discarding("<<v<<")"<<std::endl;
            return;
        }
        float x = v.x();
        if (x<-1.0f) x = -1.0f;
        if (x>1.0f) x = 1.0f;
        float y = v.y();
        if (y<-1.0f) y = -1.0f;
        if (y>1.0f) y = 1.0f;
        _bb.expandBy(osg::Vec3(x, y, v.z()));
    }
    
    void MWShadow::cull(osgUtil::CullVisitor& cv)
    {
        if (!enableShadows)
        {
            _shadowedScene->osg::Group::traverse(cv);
            return;
        }
        
        OSG_INFO << std::endl << std::endl << "ViewDependentShadowMap::cull(osg::CullVisitor&" << &cv << ")" << std::endl;

        if (!_shadowCastingStateSet)
        {
            OSG_INFO << "Warning, init() has not yet been called so ShadowCastingStateSet has not been setup yet, unable to create shadows." << std::endl;
            _shadowedScene->osg::Group::traverse(cv);
            return;
        }

        ViewDependentData* vdd = getViewDependentData(&cv);

        if (!vdd)
        {
            OSG_INFO << "Warning, now ViewDependentData created, unable to create shadows." << std::endl;
            _shadowedScene->osg::Group::traverse(cv);
            return;
        }

        ShadowSettings* settings = getShadowedScene()->getShadowSettings();

        OSG_INFO << "cv->getProjectionMatrix()=" << *cv.getProjectionMatrix() << std::endl;

        osg::CullSettings::ComputeNearFarMode cachedNearFarMode = cv.getComputeNearFarMode();

        osg::RefMatrix& viewProjectionMatrix = *cv.getProjectionMatrix();

        // check whether this main views projection is perspective or orthographic
        bool orthographicViewFrustum = viewProjectionMatrix(0, 3) == 0.0 &&
            viewProjectionMatrix(1, 3) == 0.0 &&
            viewProjectionMatrix(2, 3) == 0.0;

        double minZNear = 0.0;
        double maxZFar = DBL_MAX;

        if (cachedNearFarMode == osg::CullSettings::DO_NOT_COMPUTE_NEAR_FAR)
        {
            double left, right, top, bottom;
            if (orthographicViewFrustum)
            {
                viewProjectionMatrix.getOrtho(left, right, bottom, top, minZNear, maxZFar);
            }
            else
            {
                viewProjectionMatrix.getFrustum(left, right, bottom, top, minZNear, maxZFar);
            }
            OSG_INFO << "minZNear=" << minZNear << ", maxZFar=" << maxZFar << std::endl;
        }

        // set the compute near/far mode to the highest quality setting to ensure we push the near plan out as far as possible
        if (settings->getComputeNearFarModeOverride() != osg::CullSettings::DO_NOT_COMPUTE_NEAR_FAR)
        {
            cv.setComputeNearFarMode(settings->getComputeNearFarModeOverride());
        }

        // 1. Traverse main scene graph
        cv.pushStateSet(_shadowRecievingPlaceholderStateSet.get());

        osg::ref_ptr<osgUtil::StateGraph> decoratorStateGraph = cv.getCurrentStateGraph();

        cullShadowReceivingScene(&cv);

        cv.popStateSet();

        if (cv.getComputeNearFarMode() != osg::CullSettings::DO_NOT_COMPUTE_NEAR_FAR)
        {
            OSG_INFO << "Just done main subgraph traversak" << std::endl;
            // make sure that the near plane is computed correctly so that any projection matrix computations
            // are all done correctly.
            cv.computeNearPlane();
        }

        // clamp the minZNear and maxZFar to those provided by ShadowSettings
        maxZFar = osg::minimum(settings->getMaximumShadowMapDistance(), maxZFar);
        if (minZNear>maxZFar) minZNear = maxZFar*settings->getMinimumShadowMapNearFarRatio();

        //OSG_NOTICE<<"maxZFar "<<maxZFar<<std::endl;

        Frustum frustum(&cv, minZNear, maxZFar);

        double reducedNear, reducedFar;
        if (cv.getComputeNearFarMode() != osg::CullSettings::DO_NOT_COMPUTE_NEAR_FAR)
        {
            reducedNear = osg::maximum<double>(cv.getCalculatedNearPlane(), minZNear);
            reducedFar = osg::minimum<double>(cv.getCalculatedFarPlane(), maxZFar);
        }
        else
        {
            reducedNear = minZNear;
            reducedFar = maxZFar;
        }

        // return compute near far mode back to it's original settings
        cv.setComputeNearFarMode(cachedNearFarMode);

        OSG_INFO << "frustum.eye=" << frustum.eye << ", frustum.centerNearPlane, " << frustum.centerNearPlane << " distance = " << (frustum.eye - frustum.centerNearPlane).length() << std::endl;


        // 2. select active light sources
        //    create a list of light sources + their matrices to place them
        selectActiveLights(&cv, vdd);


        unsigned int pos_x = 0;
        unsigned int textureUnit = settings->getBaseShadowTextureUnit();
        unsigned int numValidShadows = 0;

        ShadowDataList& sdl = vdd->getShadowDataList();
        ShadowDataList previous_sdl;
        previous_sdl.swap(sdl);

        unsigned int numShadowMapsPerLight = settings->getNumShadowMapsPerLight();
        /*if (numShadowMapsPerLight>2)
        {
            OSG_NOTICE << "numShadowMapsPerLight of " << numShadowMapsPerLight << " is greater than maximum supported, falling back to 2." << std::endl;
            numShadowMapsPerLight = 2;
        }*/

        LightDataList& pll = vdd->getLightDataList();
        for (LightDataList::iterator itr = pll.begin();
            itr != pll.end();
            ++itr)
        {
            // 3. create per light/per shadow map division of lightspace/frustum
            //    create a list of light/shadow map data structures

            LightData& pl = **itr;

            // 3.1 compute light space polytope
            //
            osg::Polytope polytope = computeLightViewFrustumPolytope(frustum, pl);

            // if polytope is empty then no rendering.
            if (polytope.empty())
            {
                OSG_NOTICE << "Polytope empty no shadow to render" << std::endl;
                continue;
            }

            // 3.2 compute RTT camera view+projection matrix settings
            //
            osg::Matrixd projectionMatrix;
            osg::Matrixd viewMatrix;
            if (!computeShadowCameraSettings(frustum, pl, projectionMatrix, viewMatrix))
            {
                OSG_NOTICE << "No valid Camera settings, no shadow to render" << std::endl;
                continue;
            }

            // if we are using multiple shadow maps and CastShadowTraversalMask is being used
            // traverse the scene to compute the extents of the objects
            if (/*numShadowMapsPerLight>1 &&*/ _shadowedScene->getCastsShadowTraversalMask() != 0xffffffff)
            {
                // osg::ElapsedTime timer;

                osg::ref_ptr<osg::Viewport> viewport = new osg::Viewport(0, 0, 2048, 2048);
                ComputeLightSpaceBounds clsb(viewport.get(), projectionMatrix, viewMatrix);
                clsb.setTraversalMask(_shadowedScene->getCastsShadowTraversalMask());

                osg::Matrixd invertModelView;
                invertModelView.invert(viewMatrix);
                osg::Polytope local_polytope(polytope);
                local_polytope.transformProvidingInverse(invertModelView);

                osg::CullingSet& cs = clsb.getProjectionCullingStack().back();
                cs.setFrustum(local_polytope);
                clsb.pushCullingSet();

                _shadowedScene->accept(clsb);

                // OSG_NOTICE<<"Extents of LightSpace "<<clsb._bb.xMin()<<", "<<clsb._bb.xMax()<<", "<<clsb._bb.yMin()<<", "<<clsb._bb.yMax()<<", "<<clsb._bb.zMin()<<", "<<clsb._bb.zMax()<<std::endl;
                // OSG_NOTICE<<"  time "<<timer.elapsedTime_m()<<"ms, mask = "<<std::hex<<_shadowedScene->getCastsShadowTraversalMask()<<std::endl;

                if (clsb._bb.xMin()>-1.0f || clsb._bb.xMax()<1.0f || clsb._bb.yMin()>-1.0f || clsb._bb.yMax()<1.0f)
                {
                    // OSG_NOTICE<<"Need to clamp projection matrix"<<std::endl;

#if 1
                    double xMid = (clsb._bb.xMin() + clsb._bb.xMax())*0.5f;
                    double xRange = clsb._bb.xMax() - clsb._bb.xMin();
#else
                    double xMid = 0.0;
                    double xRange = 2.0;
#endif
                    double yMid = (clsb._bb.yMin() + clsb._bb.yMax())*0.5f;
                    double yRange = (clsb._bb.yMax() - clsb._bb.yMin());

                    osg::Matrixd cornerConverter = osg::Matrixd::inverse(projectionMatrix) * osg::Matrixd::inverse(viewMatrix) * *cv.getModelViewMatrix();
                    double minZ = DBL_MAX;
                    double maxZ = -DBL_MAX;
                    for (unsigned int i = 0; i < 8; i++)
                    {
                        osg::Vec3 corner = clsb._bb.corner(i);
                        corner = corner * cornerConverter;

                        maxZ = osg::maximum<double>(maxZ, -corner.z());
                        minZ = osg::minimum<double>(minZ, -corner.z());
                    }
                    reducedNear = osg::maximum<double>(reducedNear, minZ);
                    reducedFar = osg::minimum<double>(reducedFar, maxZ);

                    // OSG_NOTICE<<"  xMid="<<xMid<<", yMid="<<yMid<<", xRange="<<xRange<<", yRange="<<yRange<<std::endl;

                    projectionMatrix =
                        projectionMatrix *
                        osg::Matrixd::translate(osg::Vec3d(-xMid, -yMid, 0.0)) *
                        osg::Matrixd::scale(osg::Vec3d(2.0 / xRange, 2.0 / yRange, 1.0));

                }

            }

            double splitPoint = 0.0;

            if (numShadowMapsPerLight>1)
            {
                osg::Vec3d eye_v = frustum.eye * viewMatrix;
                osg::Vec3d center_v = frustum.center * viewMatrix;
                osg::Vec3d viewdir_v = center_v - eye_v; viewdir_v.normalize();
                osg::Vec3d lightdir(0.0, 0.0, -1.0);

                double dotProduct_v = lightdir * viewdir_v;
                double angle = acosf(dotProduct_v);

                osg::Vec3d eye_ls = eye_v * projectionMatrix;

                OSG_INFO << "Angle between view vector and eye " << osg::RadiansToDegrees(angle) << std::endl;
                OSG_INFO << "eye_ls=" << eye_ls << std::endl;

                if (eye_ls.y() >= -1.0 && eye_ls.y() <= 1.0)
                {
                    OSG_INFO << "Eye point inside light space clip region   " << std::endl;
                    splitPoint = 0.0;
                }
                else
                {
                    double n = -1.0 - eye_ls.y();
                    double f = 1.0 - eye_ls.y();
                    double sqrt_nf = sqrt(n*f);
                    double mid = eye_ls.y() + sqrt_nf;
                    double ratioOfMidToUseForSplit = 0.8;
                    splitPoint = mid * ratioOfMidToUseForSplit;

                    OSG_INFO << "  n=" << n << ", f=" << f << ", sqrt_nf=" << sqrt_nf << " mid=" << mid << std::endl;
                }
            }

            // 4. For each light/shadow map
            for (unsigned int sm_i = 0; sm_i<numShadowMapsPerLight; ++sm_i)
            {
                osg::ref_ptr<ShadowData> sd;

                if (previous_sdl.empty())
                {
                    OSG_INFO << "Create new ShadowData" << std::endl;
                    sd = new ShadowData(vdd);
                }
                else
                {
                    OSG_INFO << "Taking ShadowData from from of previous_sdl" << std::endl;
                    sd = previous_sdl.front();
                    previous_sdl.erase(previous_sdl.begin());
                }

                if (debugHud)
                {
                    osg::ref_ptr<osg::Texture2D> texture = sd->_texture;
                    osg::ref_ptr<osg::StateSet> stateSet = debugGeometry[sm_i]->getOrCreateStateSet();
                    stateSet->setTextureAttributeAndModes(debugTextureUnit, texture, osg::StateAttribute::ON);

                    unsigned int traversalMask = cv.getTraversalMask();
                    cv.setTraversalMask(debugGeometry[sm_i]->getNodeMask());
                    cv.pushStateSet(stateSet);
                    debugCameras[sm_i]->accept(cv);
                    cv.popStateSet();
                    cv.setTraversalMask(traversalMask);

                    cv.getState()->setCheckForGLErrors(osg::State::ONCE_PER_ATTRIBUTE);
                }

                osg::ref_ptr<osg::Camera> camera = sd->_camera;

                camera->setProjectionMatrix(projectionMatrix);
                camera->setViewMatrix(viewMatrix);

                if (settings->getDebugDraw())
                {
                    camera->getViewport()->x() = pos_x;
                    pos_x += static_cast<unsigned int>(camera->getViewport()->width()) + 40;
                }

                // transform polytope in model coords into light spaces eye coords.
                osg::Matrixd invertModelView;
                invertModelView.invert(camera->getViewMatrix());

                osg::Polytope local_polytope(polytope);
                local_polytope.transformProvidingInverse(invertModelView);


                if (numShadowMapsPerLight>1)
                {
                    // compute the start and end range in non-dimensional coords
#if 0
                    double r_start = (sm_i == 0) ? -1.0 : (double(sm_i) / double(numShadowMapsPerLight)*2.0 - 1.0);
                    double r_end = (sm_i + 1 == numShadowMapsPerLight) ? 1.0 : (double(sm_i + 1) / double(numShadowMapsPerLight)*2.0 - 1.0);
#elif 0

                    // hardwired for 2 splits
                    double r_start = (sm_i == 0) ? -1.0 : splitPoint;
                    double r_end = (sm_i + 1 == numShadowMapsPerLight) ? 1.0 : splitPoint;
#elif 0
                    double r_start, r_end;
                    // Split such that each shadow map covers a quarter of the area of the one after it
                    if (sm_i == 0)
                        r_start = -1.0;
                    else
                    {
                        r_start = (1 - pow(4.0, sm_i)) / (1 - pow(4.0, numShadowMapsPerLight));
                        r_start *= 2.0;
                        //r_start += double(sm_i) / double(numShadowMapsPerLight);
                        r_start -= 1.0;
                    }

                    if (sm_i + 1 == numShadowMapsPerLight)
                        r_end = 1.0;
                    else
                    {
                        r_end = (1 - pow(4.0, sm_i + 1)) / (1 - pow(4.0, numShadowMapsPerLight));
                        r_end *= 2.0;
                        //r_end += double(sm_i + 1) / double(numShadowMapsPerLight);
                        r_end -= 1.0;
                    }
#else
                    double r_start, r_end;

                    // split system based on the original Parallel Split Shadow Maps paper.
                    double n = reducedNear;
                    double f = reducedFar;
                    double i = double(sm_i);
                    double m = double(numShadowMapsPerLight);
                    double ratio = Settings::Manager::getFloat("split point uniform logarithmic ratio", "Shadows");
                    double deltaBias = Settings::Manager::getFloat("split point bias", "Shadows");
                    if (sm_i == 0)
                        r_start = -1.0;
                    else
                    {
                        // compute the split point in main camera view
                        double ciLog = n * pow(f / n, i / m);
                        double ciUniform = n + (f - n) * i / m;
                        double ci = ratio * ciLog + (1.0 - ratio) * ciUniform  + deltaBias;

                        // work out where this is in light space
                        osg::Vec3d worldSpacePos = frustum.eye + frustum.frustumCenterLine * ci;
                        osg::Vec3d lightSpacePos = worldSpacePos * viewMatrix * projectionMatrix;
                        r_start = lightSpacePos.y();
                    }

                    if (sm_i + 1 == numShadowMapsPerLight)
                        r_end = 1.0;
                    else
                    {
                        // compute the split point in main camera view
                        double ciLog = n * pow(f / n, (i + 1) / m);
                        double ciUniform = n + (f - n) * (i + 1) / m;
                        double ci = ratio * ciLog + (1.0 - ratio) * ciUniform + deltaBias;

                        // work out where this is in light space
                        osg::Vec3d worldSpacePos = frustum.eye + frustum.frustumCenterLine * ci;
                        osg::Vec3d lightSpacePos = worldSpacePos * viewMatrix * projectionMatrix;
                        r_end = lightSpacePos.y();
                    }
#endif

                    // for all by the last shadowmap shift the r_end so that it overlaps slightly with the next shadowmap
                    // to prevent a seam showing through between the shadowmaps
                    if (sm_i + 1<numShadowMapsPerLight) r_end += 0.01;


                    if (sm_i>0)
                    {
                        // not the first shadowmap so insert a polytope to clip the scene from before r_start

                        // plane in clip space coords
                        osg::Plane plane(0.0, 1.0, 0.0, -r_start);

                        // transform into eye coords
                        plane.transformProvidingInverse(projectionMatrix);
                        local_polytope.getPlaneList().push_back(plane);

                        //OSG_NOTICE<<"Adding r_start plane "<<plane<<std::endl;

                    }

                    if (sm_i + 1<numShadowMapsPerLight)
                    {
                        // not the last shadowmap so insert a polytope to clip the scene from beyond r_end

                        // plane in clip space coords
                        osg::Plane plane(0.0, -1.0, 0.0, r_end);

                        // transform into eye coords
                        plane.transformProvidingInverse(projectionMatrix);
                        local_polytope.getPlaneList().push_back(plane);

                        //OSG_NOTICE<<"Adding r_end plane "<<plane<<std::endl;
                    }

                    local_polytope.setupMask();


                    // OSG_NOTICE<<"Need to adjust RTT camera projection and view matrix here, r_start="<<r_start<<", r_end="<<r_end<<std::endl;
                    // OSG_NOTICE<<"  textureUnit = "<<textureUnit<<std::endl;

                    double mid_r = (r_start + r_end)*0.5;
                    double range_r = (r_end - r_start);

                    // OSG_NOTICE<<"  mid_r = "<<mid_r<<", range_r = "<<range_r<<std::endl;

                    camera->setProjectionMatrix(
                        camera->getProjectionMatrix() *
                        osg::Matrixd::translate(osg::Vec3d(0.0, -mid_r, 0.0)) *
                        osg::Matrixd::scale(osg::Vec3d(1.0, 2.0 / range_r, 1.0)));

                }


                osg::ref_ptr<VDSMCameraCullCallback> vdsmCallback = new VDSMCameraCullCallback(this, local_polytope);
                camera->setCullCallback(vdsmCallback.get());

                // 4.3 traverse RTT camera
                //

                cv.pushStateSet(_shadowCastingStateSet.get());

                cullShadowCastingScene(&cv, camera.get());

                cv.popStateSet();

                if (!orthographicViewFrustum && settings->getShadowMapProjectionHint() == osgShadow::ShadowSettings::PERSPECTIVE_SHADOW_MAP)
                {
                    adjustPerspectiveShadowMapCameraSettings(vdsmCallback->getRenderStage(), frustum, pl, camera.get());
                    if (vdsmCallback->getProjectionMatrix())
                    {
                        vdsmCallback->getProjectionMatrix()->set(camera->getProjectionMatrix());
                    }
                }

                // 4.4 compute main scene graph TexGen + uniform settings + setup state
                //
                assignTexGenSettings(&cv, camera.get(), textureUnit, sd->_texgen.get());

                // mark the light as one that has active shadows and requires shaders
                pl.textureUnits.push_back(textureUnit);

                // pass on shadow data to ShadowDataList
                sd->_textureUnit = textureUnit;

                if (textureUnit >= 8)
                {
                    OSG_NOTICE << "Shadow texture unit is invalid for texgen, will not be used." << std::endl;
                }
                else
                {
                    sdl.push_back(sd);
                }

                // increment counters.
                ++textureUnit;
                ++numValidShadows;
            }
        }

        if (numValidShadows>0)
        {
            decoratorStateGraph->setStateSet(selectStateSetForRenderingShadow(*vdd));
        }

        // OSG_NOTICE<<"End of shadow setup Projection matrix "<<*cv.getProjectionMatrix()<<std::endl;
    }

    Shader::ShaderManager::DefineMap MWShadow::getShadowDefines()
    {
        if (!enableShadows)
            return getShadowsDisabledDefines();

        Shader::ShaderManager::DefineMap definesWithShadows;
        definesWithShadows.insert(std::make_pair(std::string("shadows_enabled"), std::string("1")));
        for (int i = 0; i < numberOfShadowMapsPerLight; ++i)
            definesWithShadows["shadow_texture_unit_list"] += std::to_string(i) + ",";
        // remove extra comma
        definesWithShadows["shadow_texture_unit_list"] = definesWithShadows["shadow_texture_unit_list"].substr(0, definesWithShadows["shadow_texture_unit_list"].length() - 1);

        return definesWithShadows;
    }

    Shader::ShaderManager::DefineMap MWShadow::getShadowsDisabledDefines()
    {
        Shader::ShaderManager::DefineMap definesWithShadows;
        definesWithShadows.insert(std::make_pair(std::string("shadows_enabled"), std::string("0")));
        definesWithShadows["shadow_texture_unit_list"] = "";

        return definesWithShadows;
    }
}