/* -*-c++-*- OpenSceneGraph - Copyright (C) 1998-2009 Robert Osfield
 *
 * This library is open source and may be redistributed and/or modified under
 * the terms of the OpenSceneGraph Public License (OSGPL) version 0.0 or
 * (at your option) any later version.  The full license is in LICENSE file
 * included with this distribution, and on the openscenegraph.org website.
 *
 * This library 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
 * OpenSceneGraph Public License for more details.
*/

#include <osgVolume/MultipassTechnique>
#include <osgVolume/VolumeTile>
#include <osgVolume/VolumeScene>
#include <osgVolume/VolumeSettings>

#include <osg/Geometry>
#include <osg/ValueObject>
#include <osg/io_utils>

#include <osg/Program>
#include <osg/Material>
#include <osg/CullFace>
#include <osg/Texture1D>
#include <osg/Texture2D>
#include <osg/Texture3D>
#include <osg/TexEnvFilter>
#include <osg/TransferFunction>

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

namespace osgVolume
{

osg::Image* createDownsampledImage(osg::Image* sourceImage)
{
    osg::ref_ptr<osg::Image> targetImage = new osg::Image;

    int s_base = sourceImage->s()/2;
    int s_odd = (sourceImage->s()%2);
    int s = s_base + s_odd;

    int t_base = sourceImage->t()/2;
    int t_odd = (sourceImage->t()%2);
    int t = t_base + t_odd;

    int r_base = sourceImage->r()/2;
    int r_odd = (sourceImage->r()%2);
    int r = r_base + r_odd;

    OSG_NOTICE<<"createDownsampledImage("<<sourceImage->s()<<", "<<sourceImage->t()<<", "<<sourceImage->r()<<")"<<std::endl;
    OSG_NOTICE<<"  s_base = "<<s_base<<", s_odd = "<<s_odd<<", s="<<s<<std::endl;
    OSG_NOTICE<<"  t_base = "<<t_base<<", t_odd = "<<t_odd<<", t="<<t<<std::endl;
    OSG_NOTICE<<"  r_base = "<<r_base<<", r_odd = "<<r_odd<<", r="<<r<<std::endl;

    targetImage->allocateImage(s, t, r, sourceImage->getPixelFormat(), sourceImage->getDataType());

    int numComponents = 1;

    for(int plane=0; plane<r_base; ++plane)
    {
        for(int row=0; row<t_base; ++row)
        {
#if 0
            typedef unsigned char T;
            typedef unsigned short TL;
#else
            typedef unsigned short T;
            typedef unsigned int TL;
#endif
            T* ptr_source_1 = reinterpret_cast<T*>(sourceImage->data(0,row*2, plane*2));
            T* ptr_source_2 = reinterpret_cast<T*>(sourceImage->data(1,row*2, plane*2));
            T* ptr_source_3 = reinterpret_cast<T*>(sourceImage->data(0,row*2+1, plane*2));
            T* ptr_source_4 = reinterpret_cast<T*>(sourceImage->data(1,row*2+1, plane*2));
            T* ptr_source_5 = reinterpret_cast<T*>(sourceImage->data(0,row*2, plane*2+1));
            T* ptr_source_6 = reinterpret_cast<T*>(sourceImage->data(1,row*2, plane*2+1));
            T* ptr_source_7 = reinterpret_cast<T*>(sourceImage->data(0,row*2+1, plane*2+1));
            T* ptr_source_8 = reinterpret_cast<T*>(sourceImage->data(1,row*2+1, plane*2+1));
            T* ptr_target = reinterpret_cast<T*>(targetImage->data(0,row,plane));

            for(int column=0; column<s_base; ++column)
            {
                // average and copy across the source data.
                for(int i=0; i<numComponents; ++i)
                {
#if 1
                    TL value = static_cast<TL>(*ptr_source_1)+
                            static_cast<TL>(*ptr_source_2)+
                            static_cast<TL>(*ptr_source_3)+
                            static_cast<TL>(*ptr_source_4)+
                            static_cast<TL>(*ptr_source_5)+
                            static_cast<TL>(*ptr_source_6)+
                            static_cast<TL>(*ptr_source_7)+
                            static_cast<TL>(*ptr_source_8);
                    value /= 8;
#else
                    TL value = 0;
                    value = osg::maximum(static_cast<TL>(*ptr_source_1),value);
                    value = osg::maximum(static_cast<TL>(*ptr_source_2),value);
                    value = osg::maximum(static_cast<TL>(*ptr_source_3),value);
                    value = osg::maximum(static_cast<TL>(*ptr_source_4),value);
                    value = osg::maximum(static_cast<TL>(*ptr_source_5),value);
                    value = osg::maximum(static_cast<TL>(*ptr_source_6),value);
                    value = osg::maximum(static_cast<TL>(*ptr_source_7),value);
                    value = osg::maximum(static_cast<TL>(*ptr_source_8),value);
#endif
                    *ptr_target = static_cast<T>(value);

                    ++ptr_target;

                    ++ptr_source_1;
                    ++ptr_source_2;
                    ++ptr_source_3;
                    ++ptr_source_4;
                    ++ptr_source_5;
                    ++ptr_source_6;
                    ++ptr_source_7;
                    ++ptr_source_8;
                }
                // skip to the next set of source texels
                ptr_source_1 += numComponents;
                ptr_source_2 += numComponents;
                ptr_source_3 += numComponents;
                ptr_source_4 += numComponents;
                ptr_source_5 += numComponents;
                ptr_source_6 += numComponents;
                ptr_source_7 += numComponents;
                ptr_source_8 += numComponents;
            }
            if (s_odd)
            {

            }
        }
        if (t_odd)
        {
            OSG_NOTICE<<"Need to handle odd image row"<<std::endl;
        }
    }
    if (r_odd)
    {
        OSG_NOTICE<<"Need to handle odd image plane"<<std::endl;
    }

    return targetImage.release();
}

////////////////////////////////////////////////////////////////////////
//
// MultipassTileData
//

class RTTCameraCullCallback : public osg::NodeCallback
{
    public:

        RTTCameraCullCallback(MultipassTechnique::MultipassTileData* tileData, MultipassTechnique* mt):
            _tileData(tileData),
            _mt(mt) {}

        virtual void operator()(osg::Node* /*node*/, osg::NodeVisitor* nv)
        {
            osgUtil::CullVisitor* cv = nv->asCullVisitor();

            cv->pushProjectionMatrix(_tileData->projectionMatrix.get());

            // OSG_NOTICE<<"Traversing tile subgraph for pre-render "<<_mt->getVolumeTile()->getNumChildren()<<std::endl;

            _mt->getVolumeTile()->osg::Group::traverse(*cv);

            cv->popProjectionMatrix();
        }

    protected:

        virtual ~RTTCameraCullCallback() {}

        osg::observer_ptr<osgVolume::MultipassTechnique::MultipassTileData> _tileData;
        osg::observer_ptr<osgVolume::MultipassTechnique> _mt;
};

MultipassTechnique::MultipassTileData::MultipassTileData(osgUtil::CullVisitor* cv, MultipassTechnique* mpt):
    TileData(),
    multipassTechnique(mpt)
{
    currentRenderingMode = mpt->computeRenderingMode();

    int width = 512;
    int height = 512;

    osg::Viewport* viewport = cv->getCurrentRenderStage()->getViewport();
    if (viewport)
    {
        width = static_cast<int>(viewport->width());
        height = static_cast<int>(viewport->height());
    }

    stateset = new osg::StateSet;

    eyeToTileUniform = new osg::Uniform("eyeToTile",osg::Matrixf());
    stateset->addUniform(eyeToTileUniform.get());

    tileToImageUniform = new osg::Uniform("tileToImage",osg::Matrixf());
    stateset->addUniform(tileToImageUniform.get());

    switch(currentRenderingMode)
    {
        case(MultipassTechnique::CUBE):
        {
            // no need to set up RTT Cameras;
            OSG_NOTICE<<"Setting up MultipassTileData for CUBE rendering"<<std::endl;

            break;
        }
        case(MultipassTechnique::HULL):
        {
            OSG_NOTICE<<"Setting up MultipassTileData for HULL rendering"<<std::endl;
            setUp(frontFaceRttCamera, frontFaceDepthTexture, width, height);
            frontFaceRttCamera->setName("frontFaceRttCamera");
            frontFaceRttCamera->setCullCallback(new RTTCameraCullCallback(this, mpt));
            frontFaceRttCamera->getOrCreateStateSet()->setAttributeAndModes(new osg::CullFace(osg::CullFace::BACK), osg::StateAttribute::ON|osg::StateAttribute::OVERRIDE);

            stateset->setTextureAttribute(2, frontFaceDepthTexture.get(), osg::StateAttribute::ON|osg::StateAttribute::OVERRIDE);
            break;
        }
        case(MultipassTechnique::CUBE_AND_HULL):
        {
            OSG_NOTICE<<"Setting up MultipassTileData for CUBE_AND_HULL rendering"<<std::endl;
            setUp(frontFaceRttCamera, frontFaceDepthTexture, width, height);
            frontFaceRttCamera->setName("frontFaceRttCamera");
            frontFaceRttCamera->setCullCallback(new RTTCameraCullCallback(this, mpt));
            frontFaceRttCamera->getOrCreateStateSet()->setAttributeAndModes(new osg::CullFace(osg::CullFace::BACK), osg::StateAttribute::ON|osg::StateAttribute::OVERRIDE);

            setUp(backFaceRttCamera, backFaceDepthTexture, width, height);
            backFaceRttCamera->setName("backFaceRttCamera");
            backFaceRttCamera->setCullCallback(new RTTCameraCullCallback(this, mpt));
            backFaceRttCamera->getOrCreateStateSet()->setAttributeAndModes(new osg::CullFace(osg::CullFace::FRONT), osg::StateAttribute::ON|osg::StateAttribute::OVERRIDE);

            stateset->setTextureAttribute(2, frontFaceDepthTexture.get(), osg::StateAttribute::ON|osg::StateAttribute::OVERRIDE);
            stateset->setTextureAttribute(3, backFaceDepthTexture.get(), osg::StateAttribute::ON|osg::StateAttribute::OVERRIDE);
            break;
        }
    }

}

void MultipassTechnique::MultipassTileData::setUp(osg::ref_ptr<osg::Camera>& camera, osg::ref_ptr<osg::Texture2D>& depthTexture, int width, int height)
{
    depthTexture = new osg::Texture2D;
    depthTexture->setTextureSize(width, height);
    depthTexture->setInternalFormat(GL_DEPTH_COMPONENT);
    depthTexture->setFilter(osg::Texture2D::MIN_FILTER,osg::Texture2D::LINEAR);
    depthTexture->setFilter(osg::Texture2D::MAG_FILTER,osg::Texture2D::LINEAR);
    depthTexture->setWrap(osg::Texture2D::WRAP_S,osg::Texture2D::CLAMP_TO_BORDER);
    depthTexture->setWrap(osg::Texture2D::WRAP_T,osg::Texture2D::CLAMP_TO_BORDER);
    depthTexture->setBorderColor(osg::Vec4(1.0f,1.0f,1.0f,1.0f));

    camera = new osg::Camera;
    camera->attach(osg::Camera::DEPTH_BUFFER, depthTexture.get());
    camera->setViewport(0, 0, width, height);

    // clear the depth and colour bufferson each clear.
    camera->setClearMask(GL_DEPTH_BUFFER_BIT);

    // set the camera to render before the main camera.
    camera->setRenderOrder(osg::Camera::PRE_RENDER);

    // tell the camera to use OpenGL frame buffer object where supported.
    camera->setRenderTargetImplementation(osg::Camera::FRAME_BUFFER_OBJECT);

    camera->setReferenceFrame(osg::Transform::RELATIVE_RF);
    camera->setProjectionMatrix(osg::Matrixd::identity());
    camera->setViewMatrix(osg::Matrixd::identity());
}

void MultipassTechnique::MultipassTileData::update(osgUtil::CullVisitor* cv)
{
    if (currentRenderingMode != multipassTechnique->computeRenderingMode())
    {
        OSG_NOTICE<<"Warning: need to re-structure MP setup."<<std::endl;
    }

    active = true;
    nodePath = cv->getNodePath();
    projectionMatrix = cv->getProjectionMatrix();
    modelviewMatrix = cv->getModelViewMatrix();

    int width = 512;
    int height = 512;

    osg::Viewport* viewport = cv->getCurrentRenderStage()->getViewport();
    if (viewport)
    {
        width = static_cast<int>(viewport->width());
        height = static_cast<int>(viewport->height());
    }

    if (frontFaceDepthTexture.valid())
    {
        if (frontFaceDepthTexture->getTextureWidth()!=width || frontFaceDepthTexture->getTextureHeight()!=height)
        {
            OSG_NOTICE<<"Need to change texture size to "<<width<<", "<<height<<std::endl;
            frontFaceDepthTexture->setTextureSize(width, height);
            frontFaceRttCamera->setViewport(0, 0, width, height);
            if (frontFaceRttCamera->getRenderingCache())
            {
                frontFaceRttCamera->getRenderingCache()->releaseGLObjects(0);
            }
        }
    }

    if (backFaceDepthTexture.valid())
    {
        if (backFaceDepthTexture->getTextureWidth()!=width || backFaceDepthTexture->getTextureHeight()!=height)
        {
            OSG_NOTICE<<"Need to change texture size to "<<width<<", "<<height<<std::endl;
            backFaceDepthTexture->setTextureSize(width, height);
            backFaceRttCamera->setViewport(0, 0, width, height);
            if (backFaceRttCamera->getRenderingCache())
            {
                backFaceRttCamera->getRenderingCache()->releaseGLObjects(0);
            }
        }
    }
}

/////////////////////////////////////////////////////////////////////////////////////////
//
// MultipassTechnique
//
MultipassTechnique::MultipassTechnique()
{
}

MultipassTechnique::MultipassTechnique(const MultipassTechnique& fft,const osg::CopyOp& copyop):
    VolumeTechnique(fft,copyop)
{
}

MultipassTechnique::~MultipassTechnique()
{
}

osg::StateSet* MultipassTechnique::createStateSet(osg::StateSet* statesetPrototype, osg::Program* programPrototype, osg::Shader* shaderToAdd1, osg::Shader* shaderToAdd2)
{
    osg::ref_ptr<osg::StateSet> stateset = osg::clone(statesetPrototype, osg::CopyOp::SHALLOW_COPY);
    osg::ref_ptr<osg::Program> program = osg::clone(programPrototype, osg::CopyOp::SHALLOW_COPY);
    stateset->setAttribute(program.get());
    if (shaderToAdd1) program->addShader(shaderToAdd1);
    if (shaderToAdd2) program->addShader(shaderToAdd2);

    return stateset.release();
}

MultipassTechnique::RenderingMode MultipassTechnique::computeRenderingMode()
{
    bool hasHull = (_volumeTile->getNumChildren()>0);

    if (!hasHull)
    {
        return CUBE;
    }

    CollectPropertiesVisitor cpv(false);
    if (_volumeTile->getLayer()->getProperty())
    {
        _volumeTile->getLayer()->getProperty()->accept(cpv);
    }

    double etfValue = cpv._exteriorTransparencyFactorProperty.valid() ? cpv._exteriorTransparencyFactorProperty->getValue() : 0.0;

    if (etfValue<=0.0)
    {
        return HULL;
    }
    else if (etfValue<1.0)
    {
        return CUBE_AND_HULL;
    }
    else
    {
        return CUBE;
    }
}


void MultipassTechnique::init()
{
    OSG_INFO<<"MultipassTechnique::init()"<<std::endl;

    if (!_volumeTile)
    {
        OSG_NOTICE<<"MultipassTechnique::init(), error no volume tile assigned."<<std::endl;
        return;
    }

    if (_volumeTile->getLayer()==0)
    {
        OSG_NOTICE<<"MultipassTechnique::init(), error no layer assigend to volume tile."<<std::endl;
        return;
    }

    if (_volumeTile->getLayer()->getImage()==0)
    {
        OSG_NOTICE<<"MultipassTechnique::init(), error no image assigned to layer."<<std::endl;
        return;
    }

    OSG_NOTICE<<"MultipassTechnique::init() Need to set up"<<std::endl;

    CollectPropertiesVisitor cpv(false);
    if (_volumeTile->getLayer()->getProperty())
    {
        _volumeTile->getLayer()->getProperty()->accept(cpv);
    }

    osg::ref_ptr<osg::Geode> geode = new osg::Geode;

    {
        osg::Geometry* geom = new osg::Geometry;

        osg::Vec3Array* coords = new osg::Vec3Array(8);
        (*coords)[0] = osg::Vec3d(0.0,0.0,0.0);
        (*coords)[1] = osg::Vec3d(1.0,0.0,0.0);
        (*coords)[2] = osg::Vec3d(1.0,1.0,0.0);
        (*coords)[3] = osg::Vec3d(0.0,1.0,0.0);
        (*coords)[4] = osg::Vec3d(0.0,0.0,1.0);
        (*coords)[5] = osg::Vec3d(1.0,0.0,1.0);
        (*coords)[6] = osg::Vec3d(1.0,1.0,1.0);
        (*coords)[7] = osg::Vec3d(0.0,1.0,1.0);
        geom->setVertexArray(coords);

        osg::Vec4Array* colours = new osg::Vec4Array(1);
        (*colours)[0].set(1.0f,1.0f,1.0,1.0f);
        geom->setColorArray(colours, osg::Array::BIND_OVERALL);

        osg::DrawElementsUShort* drawElements = new osg::DrawElementsUShort(GL_QUADS);
        // bottom
        drawElements->push_back(3);
        drawElements->push_back(2);
        drawElements->push_back(1);
        drawElements->push_back(0);

        // bottom
        drawElements->push_back(7);//7623
        drawElements->push_back(6);
        drawElements->push_back(2);
        drawElements->push_back(3);

        // left
        drawElements->push_back(4);//4730
        drawElements->push_back(7);
        drawElements->push_back(3);
        drawElements->push_back(0);

        // right
        drawElements->push_back(1);//1265
        drawElements->push_back(2);
        drawElements->push_back(6);
        drawElements->push_back(5);

        // front
        drawElements->push_back(5);//5401
        drawElements->push_back(4);
        drawElements->push_back(0);
        drawElements->push_back(1);

        // top
        drawElements->push_back(4);//4567
        drawElements->push_back(5);
        drawElements->push_back(6);
        drawElements->push_back(7);

        geom->addPrimitiveSet(drawElements);

        geode->addDrawable(geom);

    }

    _transform = new osg::MatrixTransform;
    _transform->addChild(geode.get());

    // handle locators
    Locator* masterLocator = _volumeTile->getLocator();
    Locator* layerLocator = _volumeTile->getLayer()->getLocator();

    osg::TransferFunction1D* tf = 0;

    if (!masterLocator && layerLocator) masterLocator = layerLocator;
    if (!layerLocator && masterLocator) layerLocator = masterLocator;

    osg::Matrix geometryMatrix;
    if (masterLocator)
    {
        geometryMatrix = masterLocator->getTransform();
        _transform->setMatrix(geometryMatrix);
        masterLocator->applyAppropriateFrontFace(_transform->getOrCreateStateSet());
        masterLocator->addCallback(new TransformLocatorCallback(_transform.get()));
    }

    osg::Matrix imageMatrix;
    if (layerLocator)
    {
        imageMatrix = layerLocator->getTransform();
    }

    OSG_NOTICE<<"MultipassTechnique::init() : geometryMatrix = "<<geometryMatrix<<std::endl;
    OSG_NOTICE<<"MultipassTechnique::init() : imageMatrix = "<<imageMatrix<<std::endl;

    osg::ref_ptr<osg::StateSet> stateset = new osg::StateSet;
    _volumeRenderStateSet = stateset;

    // texture unit 0 is for main scene colour buffer
    // texture unit 1 is for main scene depth buffer
    // texture unit 2 is for front depth buffer of hull when required
    // texture unit 3 is for back depth depth of hull when required
    unsigned int volumeTextureUnit = 4;
    unsigned int transferFunctionTextureUnit = 5;


    // set up uniforms
    {
        stateset->addUniform(new osg::Uniform("colorTexture",0));
        stateset->addUniform(new osg::Uniform("depthTexture",1));

        stateset->setMode(GL_ALPHA_TEST,osg::StateAttribute::ON);
        //stateset->setMode(GL_DEPTH_TEST,osg::StateAttribute::OFF);

        float alphaFuncValue = 0.1;
        if (cpv._isoProperty.valid())
        {
            alphaFuncValue = cpv._isoProperty->getValue();
        }

        if (cpv._sampleRatioProperty.valid())
            stateset->addUniform(cpv._sampleRatioProperty->getUniform());
        else
            stateset->addUniform(new osg::Uniform("SampleRatioValue",1.0f));


        if (cpv._transparencyProperty.valid())
            stateset->addUniform(cpv._transparencyProperty->getUniform());
        else
            stateset->addUniform(new osg::Uniform("TransparencyValue",1.0f));

        if (cpv._exteriorTransparencyFactorProperty.valid())
            stateset->addUniform(cpv._exteriorTransparencyFactorProperty->getUniform());
        else
            stateset->addUniform(new osg::Uniform("ExteriorTransparencyFactorValue",0.0f));


        if (cpv._afProperty.valid())
            stateset->addUniform(cpv._afProperty->getUniform());
        else
            stateset->addUniform(new osg::Uniform("AlphaFuncValue",alphaFuncValue));


        if (cpv._isoProperty.valid())
            stateset->addUniform(cpv._isoProperty->getUniform());
        else
            stateset->addUniform(new osg::Uniform("IsoSurfaceValue",alphaFuncValue));

        if (cpv._tfProperty.valid())
        {
            tf = dynamic_cast<osg::TransferFunction1D*>(cpv._tfProperty->getTransferFunction());
        }

    }


    // set up 3D texture
    osg::ref_ptr<osg::Image> image_3d = _volumeTile->getLayer()->getImage();

    // create a downsampled image to use when rendering at a lower quality.
    // osg::ref_ptr<osg::Image> downsampled_image_3d = createDownsampledImage(image_3d.get());

    //image_3d = createDownsampledImage(downsampled_image_3d.get());
    // image_3d = downsampled_image_3d;

    osg::ref_ptr<osg::Texture3D> texture3D = new osg::Texture3D;
    {
        osg::Texture::InternalFormatMode internalFormatMode = osg::Texture::USE_IMAGE_DATA_FORMAT;
#define VOLUME_TYPE 2
#if VOLUME_TYPE==1
        osg::Texture::FilterMode minFilter = osg::Texture::LINEAR_MIPMAP_LINEAR;
        osg::Texture::FilterMode magFilter = osg::Texture::LINEAR;
#elif VOLUME_TYPE==2
        osg::Texture::FilterMode minFilter = osg::Texture::LINEAR;
        osg::Texture::FilterMode magFilter = osg::Texture::LINEAR;
#else
        osg::Texture::FilterMode minFilter = osg::Texture::NEAREST;
        osg::Texture::FilterMode magFilter = osg::Texture::NEAREST;
#endif

        // set up the 3d texture itself,
        // note, well set the filtering up so that mip mapping is disabled,
        // gluBuild3DMipsmaps doesn't do a very good job of handled the
        // imbalanced dimensions of the 256x256x4 texture.
        texture3D->setResizeNonPowerOfTwoHint(false);
        texture3D->setFilter(osg::Texture3D::MIN_FILTER,minFilter);
        texture3D->setFilter(osg::Texture3D::MAG_FILTER, magFilter);
        texture3D->setWrap(osg::Texture3D::WRAP_R,osg::Texture3D::CLAMP_TO_BORDER);
        texture3D->setWrap(osg::Texture3D::WRAP_S,osg::Texture3D::CLAMP_TO_BORDER);
        texture3D->setWrap(osg::Texture3D::WRAP_T,osg::Texture3D::CLAMP_TO_BORDER);
        //texture3D->setMaxAnisotropy(16.0f);
        texture3D->setBorderColor(osg::Vec4(0.0,0.0,0.0,0.0));
        if (image_3d->getPixelFormat()==GL_ALPHA ||
            image_3d->getPixelFormat()==GL_LUMINANCE)
        {
            texture3D->setInternalFormatMode(osg::Texture3D::USE_USER_DEFINED_FORMAT);
            texture3D->setInternalFormat(GL_INTENSITY);
        }
        else
        {
            texture3D->setInternalFormatMode(internalFormatMode);
        }
        texture3D->setImage(image_3d.get());

        stateset->setTextureAttributeAndModes(volumeTextureUnit, texture3D.get(), osg::StateAttribute::ON | osg::StateAttribute::OVERRIDE);

        osg::ref_ptr<osg::Uniform> baseTextureSampler = new osg::Uniform("volumeTexture", int(volumeTextureUnit));
        stateset->addUniform(baseTextureSampler.get());

        osg::ref_ptr<osg::Uniform> volumeCellSize = new osg::Uniform("volumeCellSize", osg::Vec3(1.0f/static_cast<float>(image_3d->s()),1.0f/static_cast<float>(image_3d->t()),1.0f/static_cast<float>(image_3d->r())));
        stateset->addUniform(volumeCellSize.get());

        OSG_NOTICE<<"Texture Dimensions "<<image_3d->s()<<", "<<image_3d->t()<<", "<<image_3d->r()<<std::endl;
    }

    if (tf)
    {
        OSG_NOTICE<<"Setting up TransferFunction"<<std::endl;

        float tfScale = 1.0f;
        float tfOffset = 0.0f;

        ImageLayer* imageLayer = dynamic_cast<ImageLayer*>(_volumeTile->getLayer());
        if (imageLayer)
        {
            tfOffset = (imageLayer->getTexelOffset()[3] - tf->getMinimum()) / (tf->getMaximum() - tf->getMinimum());
            tfScale = imageLayer->getTexelScale()[3] / (tf->getMaximum() - tf->getMinimum());
        }
        else
        {
            tfOffset = -tf->getMinimum() / (tf->getMaximum()-tf->getMinimum());
            tfScale = 1.0f / (tf->getMaximum()-tf->getMinimum());
        }
        osg::ref_ptr<osg::Texture1D> tf_texture = new osg::Texture1D;
        tf_texture->setImage(tf->getImage());

        tf_texture->setResizeNonPowerOfTwoHint(false);
        tf_texture->setFilter(osg::Texture::MIN_FILTER, osg::Texture::LINEAR);
        tf_texture->setFilter(osg::Texture::MAG_FILTER, osg::Texture::LINEAR);
        tf_texture->setWrap(osg::Texture::WRAP_R,osg::Texture::CLAMP_TO_EDGE);

        stateset->setTextureAttributeAndModes(transferFunctionTextureUnit, tf_texture.get(), osg::StateAttribute::ON | osg::StateAttribute::OVERRIDE);
        stateset->addUniform(new osg::Uniform("tfTexture",int(transferFunctionTextureUnit)));
        stateset->addUniform(new osg::Uniform("tfOffset",tfOffset));
        stateset->addUniform(new osg::Uniform("tfScale",tfScale));

    }

    // creates CullFace attributes to apply to front/back StateSet configurations.
    osg::ref_ptr<osg::CullFace> front_CullFace = new osg::CullFace(osg::CullFace::BACK);
    osg::ref_ptr<osg::CullFace> back_CullFace = new osg::CullFace(osg::CullFace::FRONT);

    osg::ref_ptr<osg::Shader> main_vertexShader = osgDB::readRefShaderFile(osg::Shader::VERTEX, "shaders/volume_multipass.vert");
    if (!main_vertexShader)
    {
        #include "Shaders/volume_multipass_vert.cpp"
        main_vertexShader = new osg::Shader(osg::Shader::VERTEX, volume_multipass_vert);
    }



    osg::ref_ptr<osg::Shader> computeRayColorShader = osgDB::readRefShaderFile(osg::Shader::FRAGMENT, "shaders/volume_compute_ray_color.frag");
    if (!computeRayColorShader)
    {
        #include "Shaders/volume_compute_ray_color_frag.cpp"
        computeRayColorShader = new osg::Shader(osg::Shader::FRAGMENT, volume_compute_ray_color_frag);
    }

    // clear any previous settings
    _stateSetMap.clear();


    // set up the program template for rendering just the cube
    osg::ref_ptr<osg::Shader> cube_main_fragmentShader = osgDB::readRefShaderFile(osg::Shader::FRAGMENT, "shaders/volume_multipass_cube.frag");;
    if (!cube_main_fragmentShader)
    {
        #include "Shaders/volume_multipass_cube_frag.cpp"
        cube_main_fragmentShader = new osg::Shader(osg::Shader::FRAGMENT, volume_multipass_cube_frag);
    }
    osg::ref_ptr<osg::StateSet> cube_stateset_prototype = new osg::StateSet;
    osg::ref_ptr<osg::Program> cube_program_prototype = new osg::Program;
    {
        cube_stateset_prototype->setAttributeAndModes(back_CullFace.get(), osg::StateAttribute::ON|osg::StateAttribute::OVERRIDE);

        cube_program_prototype->addShader(main_vertexShader.get());
        cube_program_prototype->addShader(cube_main_fragmentShader.get());
        cube_program_prototype->addShader(computeRayColorShader.get());
    }


    // set up the program template for rendering just the hull
    osg::ref_ptr<osg::Shader> hull_main_fragmentShader = osgDB::readRefShaderFile(osg::Shader::FRAGMENT, "shaders/volume_multipass_hull.frag");;
    if (!hull_main_fragmentShader)
    {
        #include "Shaders/volume_multipass_hull_frag.cpp"
        hull_main_fragmentShader = new osg::Shader(osg::Shader::FRAGMENT, volume_multipass_hull_frag);
    }
    osg::ref_ptr<osg::StateSet> hull_stateset_prototype = new osg::StateSet;
    osg::ref_ptr<osg::Program> hull_program_prototype = new osg::Program;
    {
        hull_stateset_prototype->setAttributeAndModes(back_CullFace.get(), osg::StateAttribute::ON|osg::StateAttribute::OVERRIDE);
        hull_stateset_prototype->addUniform(new osg::Uniform("frontFaceDepthTexture",2));

        hull_program_prototype->addShader(main_vertexShader.get());
        hull_program_prototype->addShader(hull_main_fragmentShader.get());
        hull_program_prototype->addShader(computeRayColorShader.get());
    }


    // set up the program template for rendering just the cube
    osg::ref_ptr<osg::Shader> cube_and_hull_main_fragmentShader = osgDB::readRefShaderFile(osg::Shader::FRAGMENT, "shaders/volume_multipass_cube_and_hull.frag");;
    if (!cube_and_hull_main_fragmentShader)
    {
        #include "Shaders/volume_multipass_cube_and_hull_frag.cpp"
        cube_and_hull_main_fragmentShader = new osg::Shader(osg::Shader::FRAGMENT, volume_multipass_cube_and_hull_frag);
    }
    osg::ref_ptr<osg::StateSet> cube_and_hull_stateset_prototype = new osg::StateSet;
    osg::ref_ptr<osg::Program> cube_and_hull_program_prototype = new osg::Program;
    {
        cube_and_hull_stateset_prototype->setAttributeAndModes(back_CullFace.get(), osg::StateAttribute::ON|osg::StateAttribute::OVERRIDE);
        cube_and_hull_stateset_prototype->addUniform(new osg::Uniform("frontFaceDepthTexture",2));
        cube_and_hull_stateset_prototype->addUniform(new osg::Uniform("backFaceDepthTexture",3));

        cube_and_hull_program_prototype->addShader(main_vertexShader.get());
        cube_and_hull_program_prototype->addShader(cube_and_hull_main_fragmentShader.get());
        cube_and_hull_program_prototype->addShader(computeRayColorShader.get());
    }

    // set up the rendering of the front face
    {
        _frontFaceStateSet = new osg::StateSet;

        // cull only the bac faces so we write only the front
        _frontFaceStateSet->setAttributeAndModes(front_CullFace.get(), osg::StateAttribute::ON|osg::StateAttribute::OVERRIDE);

        // set up the front falce
        osg::ref_ptr<osg::Program> program = new osg::Program;
        program->addShader(main_vertexShader.get());
        _frontFaceStateSet->setAttribute(program.get(), osg::StateAttribute::ON|osg::StateAttribute::OVERRIDE);
    }


    // STANDARD_SHADERS
    {
        // STANDARD_SHADERS without TransferFunction
        {
            osg::ref_ptr<osg::Shader> accumulateSamplesShader = osgDB::readRefShaderFile(osg::Shader::FRAGMENT, "shaders/volume_accumulateSamples_standard.frag");
            if (!accumulateSamplesShader)
            {
                #include "Shaders/volume_accumulateSamples_standard_frag.cpp"
                accumulateSamplesShader = new osg::Shader(osg::Shader::FRAGMENT, volume_accumulateSamples_standard_frag);
            }

            _stateSetMap[STANDARD_SHADERS|CUBE_SHADERS] = createStateSet(cube_stateset_prototype.get(), cube_program_prototype.get(), accumulateSamplesShader.get());
            _stateSetMap[STANDARD_SHADERS|HULL_SHADERS] = createStateSet(hull_stateset_prototype.get(), hull_program_prototype.get(), accumulateSamplesShader.get());
            _stateSetMap[STANDARD_SHADERS|CUBE_AND_HULL_SHADERS] = createStateSet(cube_and_hull_stateset_prototype.get(), cube_and_hull_program_prototype.get(), accumulateSamplesShader.get());
        }

        // STANDARD_SHADERS with TransferFunction
        if (tf)
        {
            osg::ref_ptr<osg::Shader> accumulateSamplesShader = osgDB::readRefShaderFile(osg::Shader::FRAGMENT, "shaders/volume_accumulateSamples_standard_tf.frag");
            if (!accumulateSamplesShader)
            {
                #include "Shaders/volume_accumulateSamples_standard_tf_frag.cpp"
                accumulateSamplesShader = new osg::Shader(osg::Shader::FRAGMENT, volume_accumulateSamples_standard_tf_frag);
            }

            _stateSetMap[STANDARD_SHADERS|CUBE_SHADERS|TF_SHADERS] = createStateSet(cube_stateset_prototype.get(), cube_program_prototype.get(), accumulateSamplesShader.get());
            _stateSetMap[STANDARD_SHADERS|HULL_SHADERS|TF_SHADERS] = createStateSet(hull_stateset_prototype.get(), hull_program_prototype.get(), accumulateSamplesShader.get());
            _stateSetMap[STANDARD_SHADERS|CUBE_AND_HULL_SHADERS|TF_SHADERS] = createStateSet(cube_and_hull_stateset_prototype.get(), cube_and_hull_program_prototype.get(), accumulateSamplesShader.get());
        }
    }

    // ISO_SHADERS
    if (cpv._isoProperty.valid())
    {
        // ISO_SHADERS without TransferFunction
        {
            osg::ref_ptr<osg::Shader> accumulateSamplesShader = osgDB::readRefShaderFile(osg::Shader::FRAGMENT, "shaders/volume_accumulateSamples_iso.frag");
            if (!accumulateSamplesShader)
            {
                #include "Shaders/volume_accumulateSamples_iso_frag.cpp"
                accumulateSamplesShader = new osg::Shader(osg::Shader::FRAGMENT, volume_accumulateSamples_iso_frag);
            }

            _stateSetMap[ISO_SHADERS|CUBE_SHADERS] = createStateSet(cube_stateset_prototype.get(), cube_program_prototype.get(), accumulateSamplesShader.get());
            _stateSetMap[ISO_SHADERS|HULL_SHADERS] = createStateSet(hull_stateset_prototype.get(), hull_program_prototype.get(), accumulateSamplesShader.get());
            _stateSetMap[ISO_SHADERS|CUBE_AND_HULL_SHADERS] = createStateSet(cube_and_hull_stateset_prototype.get(), cube_and_hull_program_prototype.get(), accumulateSamplesShader.get());
        }

        // ISO_SHADERS with TransferFunction
        if (tf)
        {
            osg::ref_ptr<osg::Shader> accumulateSamplesShader = osgDB::readRefShaderFile(osg::Shader::FRAGMENT, "shaders/volume_accumulateSamples_iso_tf.frag");
            if (!accumulateSamplesShader)
            {
                #include "Shaders/volume_accumulateSamples_iso_tf_frag.cpp"
                accumulateSamplesShader = new osg::Shader(osg::Shader::FRAGMENT, volume_accumulateSamples_iso_tf_frag);
            }

            _stateSetMap[ISO_SHADERS|CUBE_SHADERS|TF_SHADERS] = createStateSet(cube_stateset_prototype.get(), cube_program_prototype.get(), accumulateSamplesShader.get());
            _stateSetMap[ISO_SHADERS|HULL_SHADERS|TF_SHADERS] = createStateSet(hull_stateset_prototype.get(), hull_program_prototype.get(), accumulateSamplesShader.get());
            _stateSetMap[ISO_SHADERS|CUBE_AND_HULL_SHADERS|TF_SHADERS] = createStateSet(cube_and_hull_stateset_prototype.get(), cube_and_hull_program_prototype.get(), accumulateSamplesShader.get());
        }
    }

    // MIP_SHADERS
    if (cpv._mipProperty.valid())
    {
        // MIP_SHADERS without TransferFunction
        {
            osg::ref_ptr<osg::Shader> accumulateSamplesShader = osgDB::readRefShaderFile(osg::Shader::FRAGMENT, "shaders/volume_accumulateSamples_mip.frag");
            if (!accumulateSamplesShader)
            {
                #include "Shaders/volume_accumulateSamples_mip_frag.cpp"
                accumulateSamplesShader = new osg::Shader(osg::Shader::FRAGMENT, volume_accumulateSamples_mip_frag);
            }

            _stateSetMap[MIP_SHADERS|CUBE_SHADERS] = createStateSet(cube_stateset_prototype.get(), cube_program_prototype.get(), accumulateSamplesShader.get());
            _stateSetMap[MIP_SHADERS|HULL_SHADERS] = createStateSet(hull_stateset_prototype.get(), hull_program_prototype.get(), accumulateSamplesShader.get());
            _stateSetMap[MIP_SHADERS|CUBE_AND_HULL_SHADERS] = createStateSet(cube_and_hull_stateset_prototype.get(), cube_and_hull_program_prototype.get(), accumulateSamplesShader.get());
        }

        // MIP_SHADERS with TransferFunction
        if (tf)
        {
            osg::ref_ptr<osg::Shader> accumulateSamplesShader = osgDB::readRefShaderFile(osg::Shader::FRAGMENT, "shaders/volume_accumulateSamples_mip_tf.frag");
            if (!accumulateSamplesShader)
            {
                #include "Shaders/volume_accumulateSamples_mip_tf_frag.cpp"
                accumulateSamplesShader = new osg::Shader(osg::Shader::FRAGMENT, volume_accumulateSamples_mip_tf_frag);
            }

            _stateSetMap[MIP_SHADERS|CUBE_SHADERS|TF_SHADERS] = createStateSet(cube_stateset_prototype.get(), cube_program_prototype.get(), accumulateSamplesShader.get());
            _stateSetMap[MIP_SHADERS|HULL_SHADERS|TF_SHADERS] = createStateSet(hull_stateset_prototype.get(), hull_program_prototype.get(), accumulateSamplesShader.get());
            _stateSetMap[MIP_SHADERS|CUBE_AND_HULL_SHADERS|TF_SHADERS] = createStateSet(cube_and_hull_stateset_prototype.get(), cube_and_hull_program_prototype.get(), accumulateSamplesShader.get());
        }
    }

    // LIT_SHADERS
    if (cpv._lightingProperty.valid())
    {
        // LIT_SHADERS without TransferFunction
        {
            osg::ref_ptr<osg::Shader> accumulateSamplesShader = osgDB::readRefShaderFile(osg::Shader::FRAGMENT, "shaders/volume_accumulateSamples_lit.frag");
            if (!accumulateSamplesShader)
            {
                #include "Shaders/volume_accumulateSamples_lit_frag.cpp"
                accumulateSamplesShader = new osg::Shader(osg::Shader::FRAGMENT, volume_accumulateSamples_lit_frag);
            }

            _stateSetMap[LIT_SHADERS|CUBE_SHADERS] = createStateSet(cube_stateset_prototype.get(), cube_program_prototype.get(), accumulateSamplesShader.get());
            _stateSetMap[LIT_SHADERS|HULL_SHADERS] = createStateSet(hull_stateset_prototype.get(), hull_program_prototype.get(), accumulateSamplesShader.get());
            _stateSetMap[LIT_SHADERS|CUBE_AND_HULL_SHADERS] = createStateSet(cube_and_hull_stateset_prototype.get(), cube_and_hull_program_prototype.get(), accumulateSamplesShader.get());
        }

        // MIP_SHADERS with TransferFunction
        if (tf)
        {
            osg::ref_ptr<osg::Shader> accumulateSamplesShader = osgDB::readRefShaderFile(osg::Shader::FRAGMENT, "shaders/volume_accumulateSamples_lit_tf.frag");
            if (!accumulateSamplesShader)
            {
                #include "Shaders/volume_accumulateSamples_lit_tf_frag.cpp"
                accumulateSamplesShader = new osg::Shader(osg::Shader::FRAGMENT, volume_accumulateSamples_lit_tf_frag);
            }

            _stateSetMap[LIT_SHADERS|CUBE_SHADERS|TF_SHADERS] = createStateSet(cube_stateset_prototype.get(), cube_program_prototype.get(), accumulateSamplesShader.get());
            _stateSetMap[LIT_SHADERS|HULL_SHADERS|TF_SHADERS] = createStateSet(hull_stateset_prototype.get(), hull_program_prototype.get(), accumulateSamplesShader.get());
            _stateSetMap[LIT_SHADERS|CUBE_AND_HULL_SHADERS|TF_SHADERS] = createStateSet(cube_and_hull_stateset_prototype.get(), cube_and_hull_program_prototype.get(), accumulateSamplesShader.get());
        }
    }


    if (cpv._sampleRatioWhenMovingProperty.valid())
    {
        _whenMovingStateSet = new osg::StateSet;
        _whenMovingStateSet->addUniform(cpv._sampleRatioWhenMovingProperty->getUniform(), osg::StateAttribute::OVERRIDE | osg::StateAttribute::ON);
    }

}

void MultipassTechnique::update(osgUtil::UpdateVisitor* uv)
{
//    OSG_NOTICE<<"MultipassTechnique:update(osgUtil::UpdateVisitor* uv):"<<std::endl;
    if (getVolumeTile()->getNumChildren()>0)
    {
        getVolumeTile()->osg::Group::traverse(*uv);
    }
    else
    {
        _transform->accept(*uv);
    }
}

void MultipassTechnique::backfaceSubgraphCullTraversal(osgUtil::CullVisitor* cv)
{
    if (!cv) return;

    cv->pushStateSet(_frontFaceStateSet.get());

    if (getVolumeTile()->getNumChildren()>0)
    {
        getVolumeTile()->osg::Group::traverse(*cv);
    }
    else
    {
        _transform->accept(*cv);
    }

    cv->popStateSet();
}

class ShadingModelVisitor : public osgVolume::PropertyVisitor
{
    public:

        ShadingModelVisitor():
            PropertyVisitor(true),
            _shadingModel(VolumeSettings::Standard),
            _usesTransferFunction(false) {}

        virtual void apply(IsoSurfaceProperty& /*iso*/) { _shadingModel = VolumeSettings::Isosurface; }
        virtual void apply(MaximumIntensityProjectionProperty& /*mip*/) { _shadingModel = VolumeSettings::MaximumIntensityProjection; }
        virtual void apply(LightingProperty& /*lp*/) { _shadingModel = VolumeSettings::Light; }
        virtual void apply(TransferFunctionProperty& /*tf*/) { _usesTransferFunction = true; }
        virtual void apply(VolumeSettings& vs) { _shadingModel = vs.getShadingModel(); }

        VolumeSettings::ShadingModel    _shadingModel;
        bool                            _usesTransferFunction;

};

void MultipassTechnique::cull(osgUtil::CullVisitor* cv)
{
    std::string traversalPass;
    bool rttTraversal = cv->getUserValue("VolumeSceneTraversal", traversalPass) && traversalPass=="RenderToTexture";

    // OSG_NOTICE<<"MultipassTechnique::cull()  traversalPass="<<traversalPass<<std::endl;
    osgVolume::VolumeScene* vs = 0;
    osg::NodePath& nodePath = cv->getNodePath();
    for(osg::NodePath::reverse_iterator itr = nodePath.rbegin();
        (itr != nodePath.rend()) && (vs == 0);
        ++itr)
    {
        vs = dynamic_cast<osgVolume::VolumeScene*>(*itr);
    }

    RenderingMode renderingMode = computeRenderingMode();

    if (rttTraversal)
    {
        if (vs)
        {
            MultipassTileData* tileData = dynamic_cast<MultipassTileData*>(vs->tileVisited(cv, getVolumeTile()));
            if (tileData)
            {
                switch(renderingMode)
                {
                    case(CUBE):
                    {
                        // no work required to pre-render
                        break;
                    }
                    case(HULL):
                    {
                        if (tileData->frontFaceRttCamera.valid())  tileData->frontFaceRttCamera->accept(*cv);
                        break;
                    }
                    case(CUBE_AND_HULL):
                    {
                        // OSG_NOTICE<<"Doing pre-rendering"<<std::endl;
                        if (tileData->frontFaceRttCamera.valid())
                        {
                            // OSG_NOTICE<<"   frontFaceRttCamera"<<std::endl;
                            tileData->frontFaceRttCamera->accept(*cv);
                        }
                        if (tileData->backFaceRttCamera.valid())
                        {
                            // OSG_NOTICE<<"   backFaceRttCamera"<<std::endl;
                            tileData->backFaceRttCamera->accept(*cv);
                        }
                    }
                }
            }

            osg::BoundingBox bb;
            if (_transform.valid()) bb.expandBy(_transform->getBound());
            if (getVolumeTile()->getNumChildren()>0) bb.expandBy(getVolumeTile()->getBound());
            cv->updateCalculatedNearFar(*(cv->getModelViewMatrix()),bb);
        }
    }
    else
    {

        int shaderMask = 0;
        if (_volumeTile->getLayer()->getProperty())
        {
            ShadingModelVisitor smv;

            _volumeTile->getLayer()->getProperty()->accept(smv);

            if (smv._usesTransferFunction)
            {
                shaderMask |= TF_SHADERS;
            }

            switch(smv._shadingModel)
            {
                case(VolumeSettings::Isosurface):                       shaderMask |= ISO_SHADERS; break;
                case(VolumeSettings::MaximumIntensityProjection):       shaderMask |= MIP_SHADERS; break;
                case(VolumeSettings::Light):                            shaderMask |= LIT_SHADERS; break;
                default:                                                shaderMask |= STANDARD_SHADERS; break;
            }
        }

        switch(renderingMode)
        {
            case(CUBE): shaderMask |= CUBE_SHADERS; break;
            case(HULL): shaderMask |= HULL_SHADERS; break;
            case(CUBE_AND_HULL): shaderMask |= CUBE_AND_HULL_SHADERS; break;
        }

        if (vs)
        {
            MultipassTileData* tileData = dynamic_cast<MultipassTileData*>(vs->getTileData(cv, getVolumeTile()));
            if (tileData)
            {
                Locator* tileLocator = _volumeTile->getLocator();
                osg::Matrixd tileToEye = tileLocator->getTransform() * (*(cv->getModelViewMatrix()));
                osg::Matrixd eyeToTile;
                eyeToTile.invert(tileToEye);

                tileData->eyeToTileUniform->set(osg::Matrixf(eyeToTile));

                Locator* layerLocator = _volumeTile->getLayer()->getLocator();
                if (tileLocator==layerLocator)
                {
                    tileData->tileToImageUniform->set(osg::Matrixf::identity());
                }
                else
                {
                    osg::Matrixd tileToImage(tileLocator->getTransform() * osg::Matrixd::inverse(layerLocator->getTransform()));
                    tileData->tileToImageUniform->set(osg::Matrixf(tileToImage));
                }


                // OSG_NOTICE<<"Updating texgen"<<std::endl;
            }
        }


        osg::ref_ptr<osg::StateSet> moving_stateset = (_whenMovingStateSet.valid() && isMoving(cv)) ? _whenMovingStateSet : 0;

        if (moving_stateset.valid())
        {
            // OSG_NOTICE<<"Using MovingStateSet"<<std::endl;
            cv->pushStateSet(moving_stateset.get());
        }

        osg::ref_ptr<osg::StateSet> program_stateset = _stateSetMap[shaderMask];
        if (program_stateset.valid())
        {
            // OSG_NOTICE<<"Have program_stateset OK."<<std::endl;
            cv->pushStateSet(program_stateset.get());
            cv->pushStateSet(_volumeRenderStateSet.get());

            switch(renderingMode)
            {
                case(CUBE):
                    // OSG_NOTICE<<"Travering Transform for CUBE rendering"<<std::endl;
                    _transform->accept(*cv);
                     break;
                case(HULL):
                    // OSG_NOTICE<<"Travering children for HULL rendering"<<std::endl;
                    getVolumeTile()->osg::Group::traverse(*cv);
                    break;
                case(CUBE_AND_HULL):
                    // OSG_NOTICE<<"Travering Transform for CUBE_AND_HULL rendering"<<std::endl;
                    _transform->accept(*cv);
                    //getVolumeTile()->osg::Group::traverse(*cv);
                    break;
            }

            cv->popStateSet();
            cv->popStateSet();
        }
        else
        {
            OSG_NOTICE<<"Warning: No program available for required shader mask "<<shaderMask<<std::endl;
        }


        if (moving_stateset.valid())
        {
            // OSG_NOTICE<<"Using MovingStateSet"<<std::endl;
            cv->popStateSet();
        }
    }
}

void MultipassTechnique::cleanSceneGraph()
{
    OSG_NOTICE<<"MultipassTechnique::cleanSceneGraph()"<<std::endl;
}

void MultipassTechnique::traverse(osg::NodeVisitor& nv)
{
    // OSG_NOTICE<<"MultipassTechnique::traverse(osg::NodeVisitor& nv)"<<std::endl;
    if (!_volumeTile) return;

    // if app traversal update the frame count.
    if (nv.getVisitorType()==osg::NodeVisitor::UPDATE_VISITOR)
    {
        if (_volumeTile->getDirty()) _volumeTile->init();

        osgUtil::UpdateVisitor* uv = nv.asUpdateVisitor();
        if (uv)
        {
            update(uv);
            return;
        }

    }
    else if (nv.getVisitorType()==osg::NodeVisitor::CULL_VISITOR)
    {
        osgUtil::CullVisitor* cv = nv.asCullVisitor();
        if (cv)
        {
            cull(cv);
            return;
        }
    }


    if (_volumeTile->getDirty())
    {
        OSG_INFO<<"******* Doing init ***********"<<std::endl;
        _volumeTile->init();
    }
}


} // end of osgVolume namespace