/* -*-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/VolumeScene>
#include <osg/Geometry>
#include <osg/PrimitiveSet>
#include <osg/Depth>
#include <osg/Geode>
#include <osg/ValueObject>
#include <osg/io_utils>
#include <osgDB/ReadFile>
#include <OpenThreads/ScopedLock>
#include <limits>

using namespace osgVolume;

class RTTCameraCullCallback : public osg::NodeCallback
{
    public:

        RTTCameraCullCallback(VolumeScene* vs):
            _volumeScene(vs) {}

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

            _volumeScene->osg::Group::traverse(*nv);

            node->setUserValue("CalculatedNearPlane",double(cv->getCalculatedNearPlane()));
            node->setUserValue("CalculatedFarPlane",double(cv->getCalculatedFarPlane()));
        }

    protected:

        virtual ~RTTCameraCullCallback() {}

        osgVolume::VolumeScene* _volumeScene;
};


////////////////////////////////////////////////////////////////////////
//
// VolumeScene::ViewData
//
VolumeScene::ViewData::ViewData()
{
}

void VolumeScene::ViewData::clearTiles()
{
    for(Tiles::iterator itr = _tiles.begin();
        itr != _tiles.end();
        ++itr)
    {
        if (itr->second.valid()) itr->second->active = false;
    }
}

void VolumeScene::ViewData::visitTile(VolumeTile* /*tile*/)
{
}

////////////////////////////////////////////////////////////////////////
//
// VolumeScene
//
VolumeScene::VolumeScene()
{
}

VolumeScene::VolumeScene(const VolumeScene& vs, const osg::CopyOp& copyop):
    osg::Group(vs,copyop)
{
}


VolumeScene::~VolumeScene()
{
}

TileData* VolumeScene::tileVisited(osgUtil::CullVisitor* cv, osgVolume::VolumeTile* tile)
{
    osg::ref_ptr<ViewData> viewData;

    {
        OpenThreads::ScopedLock<OpenThreads::Mutex> lock(_viewDataMapMutex);
        viewData = _viewDataMap[cv];
    }

    //osg::BoundingBox bb(0.0f,0.0f,0.0f,1.0f,1.0f,1.0f);
    //cv->updateCalculatedNearFar(*(cv->getModelViewMatrix()),bb);

    if (viewData.valid())
    {
        osg::ref_ptr<TileData>& tileData = viewData->_tiles[tile];
        if (!tileData)
        {
            tileData = tile->getVolumeTechnique() ? tile->getVolumeTechnique()->createTileData(cv) : 0;
        }

        if (tileData)
        {
            tileData->update(cv);
        }

        return tileData.get();
    }
    return 0;
}

TileData* VolumeScene::getTileData(osgUtil::CullVisitor* cv, osgVolume::VolumeTile* tile)
{
    osg::ref_ptr<ViewData> viewData;
    {
        OpenThreads::ScopedLock<OpenThreads::Mutex> lock(_viewDataMapMutex);
        viewData = _viewDataMap[cv];
    }

    if (!viewData) return 0;

    Tiles::iterator itr = viewData->_tiles.find(tile);
    return (itr != viewData->_tiles.end()) ? itr->second.get() : 0;
}

void VolumeScene::traverse(osg::NodeVisitor& nv)
{
    osgUtil::CullVisitor* cv = nv.asCullVisitor();
    if (!cv)
    {
        Group::traverse(nv);
        return;
    }

    osg::ref_ptr<ViewData> viewData;
    bool initializeViewData = false;
    {
        OpenThreads::ScopedLock<OpenThreads::Mutex> lock(_viewDataMapMutex);
        if (!_viewDataMap[cv])
        {
            _viewDataMap[cv] = new ViewData;
            initializeViewData = true;
        }

        viewData = _viewDataMap[cv];
    }

    if (initializeViewData)
    {
        OSG_NOTICE<<"Creating ViewData"<<std::endl;

        int textureWidth = 512;
        int textureHeight = 512;

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

        // set up depth texture
        viewData->_depthTexture = new osg::Texture2D;

        viewData->_depthTexture->setTextureSize(textureWidth, textureHeight);
        viewData->_depthTexture->setInternalFormat(GL_DEPTH_COMPONENT);
        viewData->_depthTexture->setFilter(osg::Texture2D::MIN_FILTER,osg::Texture2D::LINEAR);
        viewData->_depthTexture->setFilter(osg::Texture2D::MAG_FILTER,osg::Texture2D::LINEAR);

        viewData->_depthTexture->setWrap(osg::Texture2D::WRAP_S,osg::Texture2D::CLAMP_TO_BORDER);
        viewData->_depthTexture->setWrap(osg::Texture2D::WRAP_T,osg::Texture2D::CLAMP_TO_BORDER);
        viewData->_depthTexture->setBorderColor(osg::Vec4(1.0f,1.0f,1.0f,1.0f));

        // set up color texture
        viewData->_colorTexture = new osg::Texture2D;

        viewData->_colorTexture->setTextureSize(textureWidth, textureHeight);
        viewData->_colorTexture->setInternalFormat(GL_RGBA);
        viewData->_colorTexture->setFilter(osg::Texture2D::MIN_FILTER,osg::Texture2D::LINEAR);
        viewData->_colorTexture->setFilter(osg::Texture2D::MAG_FILTER,osg::Texture2D::LINEAR);

        viewData->_colorTexture->setWrap(osg::Texture2D::WRAP_S,osg::Texture2D::CLAMP_TO_EDGE);
        viewData->_colorTexture->setWrap(osg::Texture2D::WRAP_T,osg::Texture2D::CLAMP_TO_EDGE);


        // set up the RTT Camera to capture the main scene to a color and depth texture that can be used in post processing
        viewData->_rttCamera = new osg::Camera;
        viewData->_rttCamera->setName("viewData->_rttCamera");
        viewData->_rttCamera->attach(osg::Camera::DEPTH_BUFFER, viewData->_depthTexture.get());
        viewData->_rttCamera->attach(osg::Camera::COLOR_BUFFER, viewData->_colorTexture.get());
        viewData->_rttCamera->setCullCallback(new RTTCameraCullCallback(this));
        viewData->_rttCamera->setViewport(0,0,textureWidth,textureHeight);

        // clear the depth and colour bufferson each clear.
        viewData->_rttCamera->setClearMask(GL_DEPTH_BUFFER_BIT | GL_COLOR_BUFFER_BIT);

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

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


        viewData->_rttCamera->setReferenceFrame(osg::Transform::RELATIVE_RF);
        viewData->_rttCamera->setProjectionMatrix(osg::Matrixd::identity());
        viewData->_rttCamera->setViewMatrix(osg::Matrixd::identity());

        // create mesh for rendering the RTT textures onto the screen
        osg::ref_ptr<osg::Geode> geode = new osg::Geode;
        geode->setCullingActive(false);

        viewData->_backdropSubgraph = geode;
        //geode->addDrawable(osg::createTexturedQuadGeometry(osg::Vec3(-1.0f,-1.0f,-1.0f),osg::Vec3(2.0f,0.0f,-1.0f),osg::Vec3(0.0f,2.0f,-1.0f)));

        viewData->_geometry = new osg::Geometry;
        geode->addDrawable(viewData->_geometry.get());

        viewData->_geometry->setUseDisplayList(false);
        viewData->_geometry->setUseVertexBufferObjects(false);

        viewData->_vertices = new osg::Vec3Array(4);
        viewData->_geometry->setVertexArray(viewData->_vertices.get());

        osg::ref_ptr<osg::Vec4Array> colors = new osg::Vec4Array(1);
        (*colors)[0].set(1.0f,1.0f,1.0f,1.0f);
        viewData->_geometry->setColorArray(colors.get(), osg::Array::BIND_OVERALL);

        osg::ref_ptr<osg::Vec2Array> texcoords = new osg::Vec2Array(4);
        (*texcoords)[0].set(0.0f,1.0f);
        (*texcoords)[1].set(0.0f,0.0f);
        (*texcoords)[2].set(1.0f,1.0f);
        (*texcoords)[3].set(1.0f,0.0f);
        viewData->_geometry->setTexCoordArray(0, texcoords.get(), osg::Array::BIND_PER_VERTEX);

        viewData->_geometry->addPrimitiveSet(new osg::DrawArrays(GL_TRIANGLE_STRIP,0,4));


        osg::ref_ptr<osg::StateSet> stateset = viewData->_geometry->getOrCreateStateSet();

        stateset->setMode(GL_DEPTH_TEST, osg::StateAttribute::ON);
        stateset->setMode(GL_LIGHTING, osg::StateAttribute::OFF);
        stateset->setMode(GL_BLEND, osg::StateAttribute::OFF);
        stateset->setMode(GL_ALPHA_TEST, osg::StateAttribute::OFF);
        stateset->setAttribute(new osg::Depth(osg::Depth::LEQUAL));
        stateset->setRenderBinDetails(10,"DepthSortedBin");

        osg::ref_ptr<osg::Program> program = new osg::Program;
        stateset->setAttribute(program.get());

        // get vertex shaders from source
        osg::ref_ptr<osg::Shader> vertexShader = osgDB::readRefShaderFile(osg::Shader::VERTEX, "shaders/volume_color_depth.vert");
        if (vertexShader.valid())
        {
            program->addShader(vertexShader.get());
        }
#if 0
        else
        {
            #include "Shaders/volume_color_depth_vert.cpp"
            program->addShader(new osg::Shader(osg::Shader::VERTEX, volume_color_depth_vert));
        }
#endif
        // get fragment shaders from source
        osg::ref_ptr<osg::Shader> fragmentShader = osgDB::readRefShaderFile(osg::Shader::FRAGMENT, "shaders/volume_color_depth.frag");
        if (fragmentShader.valid())
        {
            program->addShader(fragmentShader.get());
        }
#if 0
        else
        {
            #include "Shaders/volume_color_depth_frag.cpp"
            program->addShader(new osg::Shader(osg::Shader::FRAGMENT, volume_color_depth_frag));
        }
#endif
        viewData->_stateset = new osg::StateSet;
        viewData->_stateset->addUniform(new osg::Uniform("colorTexture",0));
        viewData->_stateset->addUniform(new osg::Uniform("depthTexture",1));

        viewData->_stateset->setTextureAttributeAndModes(0, viewData->_colorTexture.get(), osg::StateAttribute::ON|osg::StateAttribute::OVERRIDE);
        viewData->_stateset->setTextureAttributeAndModes(1, viewData->_depthTexture.get(), osg::StateAttribute::ON|osg::StateAttribute::OVERRIDE);

        viewData->_viewportDimensionsUniform = new osg::Uniform("viewportDimensions",osg::Vec4(0.0,0.0,1280.0,1024.0));
        viewData->_stateset->addUniform(viewData->_viewportDimensionsUniform.get());

        geode->setStateSet(viewData->_stateset.get());

    }
    else
    {
        // OSG_NOTICE<<"Reusing ViewData"<<std::endl;

    }

    osg::Matrix projectionMatrix = *(cv->getProjectionMatrix());
    osg::Matrix modelviewMatrix = *(cv->getModelViewMatrix());


    // new frame so need to clear last frames log of VolumeTiles
    viewData->clearTiles();

    osg::Viewport* viewport = cv->getCurrentRenderStage()->getViewport();
    if (viewport)
    {
        viewData->_viewportDimensionsUniform->set(osg::Vec4(viewport->x(), viewport->y(), viewport->width(),viewport->height()));

        int textureWidth = static_cast<int>(viewport->width());
        int textureHeight = static_cast<int>(viewport->height());

        if (textureWidth != viewData->_colorTexture->getTextureWidth() ||
            textureHeight != viewData->_colorTexture->getTextureHeight())
        {
            OSG_NOTICE<<"Need to change texture size to "<<textureWidth<<", "<< textureHeight<<std::endl;
            viewData->_colorTexture->setTextureSize(textureWidth, textureHeight);
            viewData->_colorTexture->dirtyTextureObject();
            viewData->_depthTexture->setTextureSize(textureWidth, textureHeight);
            viewData->_depthTexture->dirtyTextureObject();
            viewData->_rttCamera->setViewport(0, 0, textureWidth, textureHeight);
            if (viewData->_rttCamera->getRenderingCache())
            {
                viewData->_rttCamera->getRenderingCache()->releaseGLObjects(0);
            }
        }
    }

    cv->setUserValue("VolumeSceneTraversal",std::string("RenderToTexture"));

    //OSG_NOTICE<<"Ready to traverse RTT Camera"<<std::endl;
    //OSG_NOTICE<<"   RTT Camera ProjectionMatrix Before "<<viewData->_rttCamera->getProjectionMatrix()<<std::endl;
    viewData->_rttCamera->accept(nv);

    //OSG_NOTICE<<"   RTT Camera ProjectionMatrix After "<<viewData->_rttCamera->getProjectionMatrix()<<std::endl;
    //OSG_NOTICE<<"   cv ProjectionMatrix After "<<*(cv->getProjectionMatrix())<<std::endl;

    //OSG_NOTICE<<"  after RTT near ="<<cv->getCalculatedNearPlane()<<std::endl;
    //OSG_NOTICE<<"  after RTT far ="<<cv->getCalculatedFarPlane()<<std::endl;

    //OSG_NOTICE<<"tileVisited()"<<viewData->_tiles.size()<<std::endl;


    typedef osgUtil::CullVisitor::value_type NearFarValueType;
    NearFarValueType calculatedNearPlane = std::numeric_limits<NearFarValueType>::max();
    NearFarValueType calculatedFarPlane = -std::numeric_limits<NearFarValueType>::max();
    if (viewData->_rttCamera->getUserValue("CalculatedNearPlane",calculatedNearPlane) &&
        viewData->_rttCamera->getUserValue("CalculatedFarPlane",calculatedFarPlane))
    {
        calculatedNearPlane *= 0.5;
        calculatedFarPlane *= 2.0;

        //OSG_NOTICE<<"Got from RTTCamera CalculatedNearPlane="<<calculatedNearPlane<<std::endl;
        //OSG_NOTICE<<"Got from RTTCamera CalculatedFarPlane="<<calculatedFarPlane<<std::endl;
        if (calculatedNearPlane < cv->getCalculatedNearPlane()) cv->setCalculatedNearPlane(calculatedNearPlane);
        if (calculatedFarPlane > cv->getCalculatedFarPlane()) cv->setCalculatedFarPlane(calculatedFarPlane);
    }

    if (calculatedFarPlane>calculatedNearPlane)
    {
        cv->clampProjectionMatrix(projectionMatrix, calculatedNearPlane, calculatedFarPlane);
    }

    osg::Matrix inv_projectionModelViewMatrix;
    inv_projectionModelViewMatrix.invert(modelviewMatrix*projectionMatrix);

    double depth = 1.0;
    osg::Vec3d v00 = osg::Vec3d(-1.0,-1.0,depth)*inv_projectionModelViewMatrix;
    osg::Vec3d v01 = osg::Vec3d(-1.0,1.0,depth)*inv_projectionModelViewMatrix;
    osg::Vec3d v10 = osg::Vec3d(1.0,-1.0,depth)*inv_projectionModelViewMatrix;
    osg::Vec3d v11 = osg::Vec3d(1.0,1.0,depth)*inv_projectionModelViewMatrix;

    // OSG_NOTICE<<"v00= "<<v00<<std::endl;
    // OSG_NOTICE<<"v01= "<<v01<<std::endl;
    // OSG_NOTICE<<"v10= "<<v10<<std::endl;
    // OSG_NOTICE<<"v11= "<<v11<<std::endl;

    (*(viewData->_vertices))[0] = v01;
    (*(viewData->_vertices))[1] = v00;
    (*(viewData->_vertices))[2] = v11;
    (*(viewData->_vertices))[3] = v10;
    viewData->_geometry->dirtyBound();

    //OSG_NOTICE<<"  new after RTT near ="<<cv->getCalculatedNearPlane()<<std::endl;
    //OSG_NOTICE<<"  new after RTT far ="<<cv->getCalculatedFarPlane()<<std::endl;

    viewData->_backdropSubgraph->accept(*cv);

    osg::NodePath nodePathPriorToTraversingSubgraph = cv->getNodePath();
    cv->setUserValue("VolumeSceneTraversal",std::string("Post"));

    // for each tile that needs post rendering we need to add it into current RenderStage.
    Tiles& tiles = viewData->_tiles;
    for(Tiles::iterator itr = tiles.begin();
        itr != tiles.end();
        ++itr)
    {
        TileData* tileData = itr->second.get();
        if (!tileData || !(tileData->active))
        {
            OSG_INFO<<"Skipping TileData that is inactive : "<<tileData<<std::endl;
            continue;
        }

        unsigned int numStateSetPushed = 0;

        // OSG_NOTICE<<"VolumeTile to add "<<tileData->projectionMatrix.get()<<", "<<tileData->modelviewMatrix.get()<<std::endl;


        osg::NodePath& nodePath = tileData->nodePath;

        cv->getNodePath() = nodePath;
        cv->pushProjectionMatrix(tileData->projectionMatrix.get());
        cv->pushModelViewMatrix(tileData->modelviewMatrix.get(), osg::Transform::ABSOLUTE_RF_INHERIT_VIEWPOINT);


        cv->pushStateSet(viewData->_stateset.get());
        ++numStateSetPushed;

        cv->pushStateSet(tileData->stateset.get());
        ++numStateSetPushed;

        osg::NodePath::iterator np_itr = nodePath.begin();

        // skip over all nodes above VolumeScene as this will have already been traversed by CullVisitor
        while(np_itr!=nodePath.end() && (*np_itr)!=viewData->_rttCamera.get()) { ++np_itr; }
        if (np_itr!=nodePath.end()) ++np_itr;

        // push the stateset on the nodes between this VolumeScene and the VolumeTile
        for(osg::NodePath::iterator ss_itr = np_itr;
            ss_itr != nodePath.end();
            ++ss_itr)
        {
            if ((*ss_itr)->getStateSet())
            {
                numStateSetPushed++;
                cv->pushStateSet((*ss_itr)->getStateSet());
                // OSG_NOTICE<<"  pushing StateSet"<<std::endl;
            }
        }
        cv->traverse(*(tileData->nodePath.back()));

        // pop the StateSet's
        for(unsigned int i=0; i<numStateSetPushed; ++i)
        {
            cv->popStateSet();
            // OSG_NOTICE<<"  popping StateSet"<<std::endl;
        }

        cv->popModelViewMatrix();
        cv->popProjectionMatrix();
    }

    // need to synchronize projection matrices:
    //    current CV projection matrix
    //    main scene RTT Camera projection matrix
    //    each tile RTT Camera
    //    each tile final render.

    cv->getNodePath() = nodePathPriorToTraversingSubgraph;
}