/***************************************************************************
 *   Copyright (c) 2009 Werner Mayer <wmayer[at]users.sourceforge.net>     *
 *                                                                         *
 *   This file is part of the FreeCAD CAx development system.              *
 *                                                                         *
 *   This library is free software; you can redistribute it and/or         *
 *   modify it under the terms of the GNU Library General Public           *
 *   License as published by the Free Software Foundation; either          *
 *   version 2 of the License, or (at your option) any later version.      *
 *                                                                         *
 *   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         *
 *   GNU Library General Public License for more details.                  *
 *                                                                         *
 *   You should have received a copy of the GNU Library General Public     *
 *   License along with this library; see the file COPYING.LIB. If not,    *
 *   write to the Free Software Foundation, Inc., 59 Temple Place,         *
 *   Suite 330, Boston, MA  02111-1307, USA                                *
 *                                                                         *
 ***************************************************************************/


#include "PreCompiled.h"

#ifndef _PreComp_
# include <algorithm>
# ifdef FC_OS_MACOSX
# include <OpenGL/gl.h>
# include <OpenGL/glu.h>
# include <OpenGL/glext.h>
# else
# include <GL/gl.h>
# include <GL/glu.h>
# include <GL/glext.h>
# endif
# include <Inventor/actions/SoGLRenderAction.h>
# include <Inventor/bundles/SoMaterialBundle.h>
# include <Inventor/elements/SoCoordinateElement.h>
# include <Inventor/elements/SoGLCoordinateElement.h>
# include <Inventor/elements/SoGLLazyElement.h>
# include <Inventor/elements/SoMaterialBindingElement.h>
# include <Inventor/elements/SoNormalBindingElement.h>
# include <Inventor/elements/SoProjectionMatrixElement.h>
# include <Inventor/elements/SoViewingMatrixElement.h>
# include <Inventor/errors/SoDebugError.h>
#endif

#include <Inventor/C/glue/gl.h>

#include <Gui/SoFCInteractiveElement.h>
#include <Gui/SoFCSelectionAction.h>
#include "SoFCIndexedFaceSet.h"
#include <QtOpenGL.h>

#ifdef HAVE_QT5_OPENGL
#define RENDER_GL_VAO
#endif
//#define RENDER_GLARRAYS

#ifdef RENDER_GL_VAO
#include <QOpenGLBuffer>
#include <QOpenGLFunctions>
#endif



using namespace MeshGui;

#if defined RENDER_GL_VAO
class MeshRenderer::Private : protected QOpenGLFunctions {
public:
    QOpenGLBuffer vertices;
    QOpenGLBuffer indices;
    const SbColor * pcolors;
    SoMaterialBindingElement::Binding matbinding;

    Private();
    void generateGLArrays(SoMaterialBindingElement::Binding matbind,
        std::vector<float>& vertex, std::vector<int32_t>& index);
    void renderFacesGLArray(SoGLRenderAction*);
    void renderCoordsGLArray(SoGLRenderAction *action);
};

MeshRenderer::Private::Private()
  : vertices(QOpenGLBuffer::VertexBuffer)
  , indices(QOpenGLBuffer::IndexBuffer)
  , pcolors(0)
  , matbinding(SoMaterialBindingElement::OVERALL)
{
    initializeOpenGLFunctions();

    vertices.create();
    indices.create();

    vertices.setUsagePattern(QOpenGLBuffer::StaticDraw);
    indices.setUsagePattern(QOpenGLBuffer::StaticDraw);
}

void MeshRenderer::Private::generateGLArrays(SoMaterialBindingElement::Binding matbind,
                                             std::vector<float>& vertex, std::vector<int32_t>& index)
{
    if (vertex.empty() || index.empty())
        return;
    vertices.bind();
    vertices.allocate(&(vertex[0]),
                      vertex.size() * sizeof(float));
    vertices.release();

    indices.bind();
    indices.allocate(&(index[0]),
                     index.size() * sizeof(int32_t));
    indices.release();
    this->matbinding = matbind;
}

void MeshRenderer::Private::renderFacesGLArray(SoGLRenderAction *)
{
    glEnableClientState(GL_NORMAL_ARRAY);
    glEnableClientState(GL_VERTEX_ARRAY);

    vertices.bind();
    indices.bind();

    if (matbinding != SoMaterialBindingElement::OVERALL)
        glInterleavedArrays(GL_C4F_N3F_V3F, 0, 0);
    else
        glInterleavedArrays(GL_N3F_V3F, 0, 0);
    glDrawElements(GL_TRIANGLES, indices.size() / sizeof(uint32_t),
                   GL_UNSIGNED_INT, NULL);

    vertices.release();
    indices.release();
    glDisableClientState(GL_VERTEX_ARRAY);
    glDisableClientState(GL_NORMAL_ARRAY);
}

void MeshRenderer::Private::renderCoordsGLArray(SoGLRenderAction *)
{
    glEnableClientState(GL_NORMAL_ARRAY);
    glEnableClientState(GL_VERTEX_ARRAY);

    vertices.bind();
    indices.bind();

    if (matbinding != SoMaterialBindingElement::OVERALL)
        glInterleavedArrays(GL_C4F_N3F_V3F, 0, 0);
    else
        glInterleavedArrays(GL_N3F_V3F, 0, 0);
    glDrawElements(GL_POINTS, indices.size() / sizeof(uint32_t),
                   GL_UNSIGNED_INT, NULL);

    vertices.release();
    indices.release();
    glDisableClientState(GL_VERTEX_ARRAY);
    glDisableClientState(GL_NORMAL_ARRAY);
}
#elif defined RENDER_GLARRAYS
class MeshRenderer::Private {
public:
    std::vector<int32_t> index_array;
    std::vector<float> vertex_array;
    const SbColor * pcolors;
    SoMaterialBindingElement::Binding matbinding;

    Private()
      : pcolors(0)
      , matbinding(SoMaterialBindingElement::OVERALL)
    {
    }

    void generateGLArrays(SoMaterialBindingElement::Binding matbind,
        std::vector<float>& vertex, std::vector<int32_t>& index);
    void renderFacesGLArray(SoGLRenderAction *action);
    void renderCoordsGLArray(SoGLRenderAction *action);
};

void MeshRenderer::Private::generateGLArrays(SoMaterialBindingElement::Binding matbind,
                                             std::vector<float>& vertex, std::vector<int32_t>& index)
{
    if (vertex.empty() || index.empty())
        return;

    this->index_array.resize(0);
    this->vertex_array.resize(0);

    this->index_array.swap(index);
    this->vertex_array.swap(vertex);
    this->matbinding = matbind;
}

void MeshRenderer::Private::renderFacesGLArray(SoGLRenderAction *action)
{
#if 0 // use Inventor's coordIndex saves memory but the rendering is very slow then
    const cc_glglue * glue = cc_glglue_instance(action->getCacheContext());
    PFNGLPRIMITIVERESTARTINDEXPROC glPrimitiveRestartIndex = (PFNGLPRIMITIVERESTARTINDEXPROC)
        cc_glglue_getprocaddress(glue, "glPrimitiveRestartIndex");

    int cnt = coordIndex.getNum();

    glEnableClientState(GL_NORMAL_ARRAY);
    glEnableClientState(GL_VERTEX_ARRAY);

    // https://www.opengl.org/discussion_boards/archive/index.php/t-180767.html
    // https://www.khronos.org/opengl/wiki/Vertex_Rendering#Primitive_Restart
    glPrimitiveRestartIndex(0xffffffff);
    glEnable(GL_PRIMITIVE_RESTART);
    //glEnable(GL_PRIMITIVE_RESTART_FIXED_INDEX);

    glInterleavedArrays(GL_N3F_V3F, 0, &(vertex_array[0]));
    glDrawElements(GL_TRIANGLES, cnt, GL_UNSIGNED_INT, coordIndex.getValues(0));

    glDisable(GL_PRIMITIVE_RESTART);
    //glDisable(GL_PRIMITIVE_RESTART_FIXED_INDEX);
    glDisableClientState(GL_VERTEX_ARRAY);
    glDisableClientState(GL_NORMAL_ARRAY);
#else // Needs more memory but makes it very fast
    (void)action;
    int cnt = index_array.size();

    glEnableClientState(GL_NORMAL_ARRAY);
    glEnableClientState(GL_VERTEX_ARRAY);

    if (matbinding != SoMaterialBindingElement::OVERALL)
        glInterleavedArrays(GL_C4F_N3F_V3F, 0, &(vertex_array[0]));
    else
        glInterleavedArrays(GL_N3F_V3F, 0, &(vertex_array[0]));
    glDrawElements(GL_TRIANGLES, cnt, GL_UNSIGNED_INT, &(index_array[0]));

    glDisableClientState(GL_VERTEX_ARRAY);
    glDisableClientState(GL_NORMAL_ARRAY);
#endif
}

void MeshRenderer::Private::renderCoordsGLArray(SoGLRenderAction *)
{
    int cnt = index_array.size();

    glEnableClientState(GL_NORMAL_ARRAY);
    glEnableClientState(GL_VERTEX_ARRAY);

    if (matbinding != SoMaterialBindingElement::OVERALL)
        glInterleavedArrays(GL_C4F_N3F_V3F, 0, &(vertex_array[0]));
    else
        glInterleavedArrays(GL_N3F_V3F, 0, &(vertex_array[0]));
    glDrawElements(GL_POINTS, cnt, GL_UNSIGNED_INT, &(index_array[0]));

    glDisableClientState(GL_VERTEX_ARRAY);
    glDisableClientState(GL_NORMAL_ARRAY);
}
#else
class MeshRenderer::Private {
public:
    const SbColor * pcolors;
    SoMaterialBindingElement::Binding matbinding;

    Private()
      : pcolors(0)
      , matbinding(SoMaterialBindingElement::OVERALL)
    {
    }

    void generateGLArrays(SoMaterialBindingElement::Binding,
        std::vector<float>&, std::vector<int32_t>&)
    {
    }
    void renderFacesGLArray(SoGLRenderAction *)
    {
    }
    void renderCoordsGLArray(SoGLRenderAction *)
    {
    }
};
#endif

MeshRenderer::MeshRenderer()
  : p(new Private)
{
}

MeshRenderer::~MeshRenderer()
{
    delete p;
}

void MeshRenderer::generateGLArrays(SoState* state, SoMaterialBindingElement::Binding matbind,
                                    std::vector<float>& vertex, std::vector<int32_t>& index)
{
    SoGLLazyElement* gl = SoGLLazyElement::getInstance(state);
    if (gl) {
        p->pcolors = gl->getDiffusePointer();
    }
    p->generateGLArrays(matbind, vertex, index);
}

// Implementation                            | FPS
// ================================================
// drawCoords (every 4th vertex)             | 20.0
// renderCoordsGLArray (all vertexes)        | 20.0
// 
void MeshRenderer::renderCoordsGLArray(SoGLRenderAction *action)
{
    p->renderCoordsGLArray(action);
}

//****************************************************************************
// renderFacesGLArray: normal and coord from vertex_array;
// no texture, color, highlight or selection but highest possible speed;
// all vertices written in one go!
//
// Benchmark tests with an 256 MB STL file:
//
// Implementation                            | FPS
// ================================================
// OpenInventor (SoIndexedFaceSet)           |  3.0
// Custom OpenInventor (SoFCMeshObjectShape) |  8.5
// With GL_PRIMITIVE_RESTART                 |  0.9
// With GL_PRIMITIVE_RESTART_FIXED_INDEX     |  0.9
// Without GL_PRIMITIVE_RESTART              |  8.5
// Vertex-Array-Object (RENDER_GL_VAO)       | 60.0
void MeshRenderer::renderFacesGLArray(SoGLRenderAction *action)
{
    p->renderFacesGLArray(action);
}

bool MeshRenderer::matchMaterial(SoState* state) const
{
    SoMaterialBindingElement::Binding matbind =
        SoMaterialBindingElement::get(state);
    const SbColor * pcolors = 0;
    SoGLLazyElement* gl = SoGLLazyElement::getInstance(state);
    if (gl) {
        pcolors = gl->getDiffusePointer();
    }
    return p->matbinding == matbind && p->pcolors == pcolors;
}

bool MeshRenderer::shouldRenderDirectly(bool direct)
{
#ifdef RENDER_GL_VAO
    Q_UNUSED(direct);
    return false;
#else
    return direct;
#endif
}

// ----------------------------------------------------------------------------

SO_ENGINE_SOURCE(SoFCMaterialEngine);

SoFCMaterialEngine::SoFCMaterialEngine()
{
    SO_ENGINE_CONSTRUCTOR(SoFCMaterialEngine);

    SO_ENGINE_ADD_INPUT(diffuseColor, (SbColor(0.0, 0.0, 0.0)));
    SO_ENGINE_ADD_OUTPUT(trigger, SoSFBool);
}

SoFCMaterialEngine::~SoFCMaterialEngine()
{
}

void SoFCMaterialEngine::initClass()
{
    SO_ENGINE_INIT_CLASS(SoFCMaterialEngine, SoEngine, "Engine");
}

void SoFCMaterialEngine::inputChanged(SoField *)
{
    SO_ENGINE_OUTPUT(trigger, SoSFBool, setValue(true));
}

void SoFCMaterialEngine::evaluate()
{
    // do nothing here
}

// ----------------------------------------------------------------------------

SO_NODE_SOURCE(SoFCIndexedFaceSet);

void SoFCIndexedFaceSet::initClass()
{
    SO_NODE_INIT_CLASS(SoFCIndexedFaceSet, SoIndexedFaceSet, "IndexedFaceSet");
}

SoFCIndexedFaceSet::SoFCIndexedFaceSet()
  : renderTriangleLimit(100000)
  , selectBuf(0)
{
    SO_NODE_CONSTRUCTOR(SoFCIndexedFaceSet);
    SO_NODE_ADD_FIELD(updateGLArray, (false));
    updateGLArray.setFieldType(SoField::EVENTOUT_FIELD);
    setName(SoFCIndexedFaceSet::getClassTypeId().getName());
}

/**
 * Either renders the complete mesh or only a subset of the points.
 */
void SoFCIndexedFaceSet::GLRender(SoGLRenderAction *action)
{
    if (this->coordIndex.getNum() < 3)
        return;

    if (!this->shouldGLRender(action)) {
        // Transparency is handled inside 'shouldGLRender' but the base class
        // somehow misses to reset the blending mode. This causes SoGLLazyElement
        // not to switch on and off GL_BLEND mode and thus transparency doesn't
        // work as expected. Calling SoMaterialBundle::sendFirst seems to fix the
        // problem.
        SoMaterialBundle mb(action);
        mb.sendFirst();
        return;
    }

    SoState * state = action->getState();
    SbBool mode = Gui::SoFCInteractiveElement::get(state);

#if defined(RENDER_GL_VAO)
    if (mode == false || render.matchMaterial(state)) {
#else
    unsigned int num = this->coordIndex.getNum()/4;
    if (mode == false || num <= this->renderTriangleLimit) {
#endif
#if defined (RENDER_GLARRAYS) || defined(RENDER_GL_VAO)

#if 0
        SoMaterialBindingElement::Binding matbind =
            SoMaterialBindingElement::get(state);

        if (matbind == SoMaterialBindingElement::OVERALL) {
            SoMaterialBundle mb(action);
            mb.sendFirst();
            if (updateGLArray) {
                updateGLArray = false;
                generateGLArrays(state);
            }
            render.renderFacesGLArray(action);
        }
        else {
            inherited::GLRender(action);
        }
#else
        if (updateGLArray.getValue()) {
            updateGLArray = false;
            generateGLArrays(state);
        }

        if (render.matchMaterial(state)) {
            SoMaterialBundle mb(action);
            mb.sendFirst();
            render.renderFacesGLArray(action);
        }
        else {
            inherited::GLRender(action);
        }
#endif
#else
        inherited::GLRender(action);
#endif
    }
    else {
#if 0 && defined (RENDER_GLARRAYS)
        SoMaterialBundle mb(action);
        mb.sendFirst();
        render.renderCoordsGLArray(action);
#else
        SoMaterialBindingElement::Binding matbind =
            SoMaterialBindingElement::get(state);
        int32_t binding = (int32_t)(matbind);

        const SoCoordinateElement * coords;
        const SbVec3f * normals;
        const int32_t * cindices;
        int numindices;
        const int32_t * nindices;
        const int32_t * tindices;
        const int32_t * mindices;
        SbBool normalCacheUsed;

        SoMaterialBundle mb(action);

        SoTextureCoordinateBundle tb(action, true, false);
        SbBool sendNormals = !mb.isColorOnly() || tb.isFunction();

        this->getVertexData(state, coords, normals, cindices,
                            nindices, tindices, mindices, numindices,
                            sendNormals, normalCacheUsed);

        mb.sendFirst(); // make sure we have the correct material

        drawCoords(static_cast<const SoGLCoordinateElement*>(coords), cindices, numindices,
                   normals, nindices, &mb, mindices, binding, &tb, tindices);
        // Disable caching for this node
        SoGLCacheContextElement::shouldAutoCache(state, SoGLCacheContextElement::DONT_AUTO_CACHE);
#endif
    }
}

void SoFCIndexedFaceSet::drawCoords(const SoGLCoordinateElement * const vertexlist,
                                    const int32_t *vertexindices,
                                    int numindices,
                                    const SbVec3f *normals,
                                    const int32_t *normalindices,
                                    SoMaterialBundle *materials,
                                    const int32_t * /*matindices*/,
                                    const int32_t binding,
                                    const SoTextureCoordinateBundle * const /*texcoords*/,
                                    const int32_t * /*texindices*/)
{
    const SbVec3f * coords3d = 0;
    coords3d = vertexlist->getArrayPtr3();

    int mod = numindices/(4*this->renderTriangleLimit)+1;
    float size = std::min<float>((float)mod,3.0f);
    glPointSize(size);

    SbBool per_face = false;
    SbBool per_vert = false;
    switch (binding) {
        case SoMaterialBindingElement::PER_FACE:
            per_face = true;
            break;
        case SoMaterialBindingElement::PER_VERTEX:
            per_vert = true;
            break;
        default:
            break;
    }

    int ct=0;
    const int32_t *viptr = vertexindices;
    int32_t v1, v2, v3;
    SbVec3f dummynormal(0,0,1);
    const SbVec3f *currnormal = &dummynormal;
    if (normals) currnormal = normals;

    glBegin(GL_POINTS);
    for (int index=0; index<numindices; ct++) {
        if (ct%mod==0) {
            if (per_face)
                materials->send(ct, true);
            v1 = *viptr++; index++;
            if (per_vert)
                materials->send(v1, true);
            if (normals)
                currnormal = &normals[*normalindices++];
            glNormal3fv((const GLfloat*)currnormal);
            glVertex3fv((const GLfloat*)(coords3d + v1));

            v2 = *viptr++; index++;
            if (per_vert)
                materials->send(v2, true);
            if (normals)
                currnormal = &normals[*normalindices++];
            glNormal3fv((const GLfloat*)currnormal);
            glVertex3fv((const GLfloat*)(coords3d + v2));

            v3 = *viptr++; index++;
            if (per_vert)
                materials->send(v3, true);
            if (normals)
                currnormal = &normals[*normalindices++];
            glNormal3fv((const GLfloat*)currnormal);
            glVertex3fv((const GLfloat*)(coords3d + v3));
        }
        else {
            viptr++; index++; normalindices++;
            viptr++; index++; normalindices++;
            viptr++; index++; normalindices++;
        }

        viptr++; index++; normalindices++;
    }
    glEnd();
}

void SoFCIndexedFaceSet::invalidate()
{
    updateGLArray = true;
}

void SoFCIndexedFaceSet::generateGLArrays(SoState * state)
{
    const SoCoordinateElement * coords;
    const SbVec3f * normals;
    const int32_t * cindices;
    const SbColor * pcolors = 0;
    const float * transp = 0;
    int numindices, numcolors = 0, numtransp = 0;
    const int32_t * nindices;
    const int32_t * tindices;
    const int32_t * mindices;
    SbBool normalCacheUsed;

    SbBool sendNormals = true;

    this->getVertexData(state, coords, normals, cindices,
                        nindices, tindices, mindices, numindices,
                        sendNormals, normalCacheUsed);

    const SbVec3f * points = coords->getArrayPtr3();

    SoMaterialBindingElement::Binding matbind =
        SoMaterialBindingElement::get(state);
    SoGLLazyElement* gl = SoGLLazyElement::getInstance(state);
    if (gl) {
        pcolors = gl->getDiffusePointer();
        numcolors = gl->getNumDiffuse();
        transp = gl->getTransparencyPointer();
        numtransp = gl->getNumTransparencies();
        Q_UNUSED(numtransp);
    }

    std::vector<float> face_vertices;
    std::vector<int32_t> face_indices;

    std::size_t numTria = numindices / 4;

    if (!mindices && matbind == SoMaterialBindingElement::PER_VERTEX_INDEXED) {
        mindices = cindices;
    }

    SoNormalBindingElement::Binding normbind = SoNormalBindingElement::get(state);
    if (normbind == SoNormalBindingElement::PER_VERTEX_INDEXED) {
        if (matbind == SoMaterialBindingElement::PER_FACE) {
            face_vertices.reserve(3 * numTria * 10); // duplicate each vertex (rgba, normal, vertex)
            face_indices.resize(3 * numTria);

            if (numcolors != static_cast<int>(numTria)) {
                SoDebugError::postWarning("SoFCIndexedFaceSet::generateGLArrays",
                                          "The number of faces (%d) doesn't match with the number of colors (%d).", numTria, numcolors);
            }

            // the nindices must have the length of numindices
            int32_t vertex = 0;
            int index = 0;
            float t = transp[0];
            for (std::size_t i=0; i<numTria; i++) {
                const SbColor& c = pcolors[i];
                for (int j=0; j<3; j++) {
                    face_vertices.push_back(c[0]);
                    face_vertices.push_back(c[1]);
                    face_vertices.push_back(c[2]);
                    face_vertices.push_back(t);

                    const SbVec3f& n = normals[nindices[index]];
                    face_vertices.push_back(n[0]);
                    face_vertices.push_back(n[1]);
                    face_vertices.push_back(n[2]);

                    const SbVec3f& p = points[cindices[index]];
                    face_vertices.push_back(p[0]);
                    face_vertices.push_back(p[1]);
                    face_vertices.push_back(p[2]);

                    face_indices[vertex] = vertex;
                    vertex++;
                    index++;
                }
                index++;
            }
        }
        else if (matbind == SoMaterialBindingElement::PER_VERTEX_INDEXED) {
            face_vertices.reserve(3 * numTria * 10); // duplicate each vertex (rgba, normal, vertex)
            face_indices.resize(3 * numTria);

            if (numcolors != coords->getNum()) {
                SoDebugError::postWarning("SoFCIndexedFaceSet::generateGLArrays",
                                          "The number of points (%d) doesn't match with the number of colors (%d).", coords->getNum(), numcolors);
            }

            // the nindices must have the length of numindices
            int32_t vertex = 0;
            int index = 0;
            float t = transp[0];
            for (std::size_t i=0; i<numTria; i++) {
                for (int j=0; j<3; j++) {
                    const SbColor& c = pcolors[mindices[index]];
                    face_vertices.push_back(c[0]);
                    face_vertices.push_back(c[1]);
                    face_vertices.push_back(c[2]);
                    face_vertices.push_back(t);

                    const SbVec3f& n = normals[nindices[index]];
                    face_vertices.push_back(n[0]);
                    face_vertices.push_back(n[1]);
                    face_vertices.push_back(n[2]);

                    const SbVec3f& p = points[cindices[index]];
                    face_vertices.push_back(p[0]);
                    face_vertices.push_back(p[1]);
                    face_vertices.push_back(p[2]);

                    face_indices[vertex] = vertex;
                    vertex++;
                    index++;
                }
                index++;
            }
        }
        else {
            // only an overall material
            matbind = SoMaterialBindingElement::OVERALL;

            face_vertices.reserve(3 * numTria * 6); // duplicate each vertex (normal, vertex)
            face_indices.resize(3 * numTria);

            // the nindices must have the length of numindices
            int32_t vertex = 0;
            int index = 0;
            for (std::size_t i=0; i<numTria; i++) {
                for (int j=0; j<3; j++) {
                    const SbVec3f& n = normals[nindices[index]];
                    face_vertices.push_back(n[0]);
                    face_vertices.push_back(n[1]);
                    face_vertices.push_back(n[2]);

                    const SbVec3f& p = points[cindices[index]];
                    face_vertices.push_back(p[0]);
                    face_vertices.push_back(p[1]);
                    face_vertices.push_back(p[2]);

                    face_indices[vertex] = vertex;
                    vertex++;
                    index++;
                }
                index++;
            }
        }
    }
    else if (normbind == SoNormalBindingElement::PER_VERTEX) {
        // only an overall material
        matbind = SoMaterialBindingElement::OVERALL;

        std::size_t numPts = coords->getNum();
        face_vertices.reserve(6 * numPts);
        for (std::size_t i=0; i<numPts; i++) {
            const SbVec3f& n = normals[i];
            face_vertices.push_back(n[0]);
            face_vertices.push_back(n[1]);
            face_vertices.push_back(n[2]);

            const SbVec3f& p = coords->get3(i);
            face_vertices.push_back(p[0]);
            face_vertices.push_back(p[1]);
            face_vertices.push_back(p[2]);

        }

        face_indices.reserve(3 * numTria);

        int index = 0;
        for (std::size_t i=0; i<numTria; i++) {
            for (int j=0; j<3; j++) {
                face_indices.push_back(cindices[index]);
                index++;
            }
            index++;
        }
    }

    render.generateGLArrays(state, matbind, face_vertices, face_indices);
}

void SoFCIndexedFaceSet::doAction(SoAction * action)
{
    if (action->getTypeId() == Gui::SoGLSelectAction::getClassTypeId()) {
        SoNode* node = action->getNodeAppliedTo();
        if (!node) return; // on no node applied

        // The node we have is the parent of this node and the coordinate node
        // thus we search there for it.
        SoSearchAction sa;
        sa.setInterest(SoSearchAction::FIRST);
        sa.setSearchingAll(false);
        sa.setType(SoCoordinate3::getClassTypeId(), 1);
        sa.apply(node);
        SoPath * path = sa.getPath();
        if (!path) return;

        // make sure we got the node we wanted
        SoNode* coords = path->getNodeFromTail(0);
        if (!(coords && coords->getTypeId().isDerivedFrom(SoCoordinate3::getClassTypeId())))
            return;
        startSelection(action);
        renderSelectionGeometry(static_cast<SoCoordinate3*>(coords)->point.getValues(0));
        stopSelection(action);
    }
    else if (action->getTypeId() == Gui::SoVisibleFaceAction::getClassTypeId()) {
        SoNode* node = action->getNodeAppliedTo();
        if (!node) return; // on no node applied

        // The node we have is the parent of this node and the coordinate node
        // thus we search there for it.
        SoSearchAction sa;
        sa.setInterest(SoSearchAction::FIRST);
        sa.setSearchingAll(false);
        sa.setType(SoCoordinate3::getClassTypeId(), 1);
        sa.apply(node);
        SoPath * path = sa.getPath();
        if (!path) return;

        // make sure we got the node we wanted
        SoNode* coords = path->getNodeFromTail(0);
        if (!(coords && coords->getTypeId().isDerivedFrom(SoCoordinate3::getClassTypeId())))
            return;
        startVisibility(action);
        renderVisibleFaces(static_cast<SoCoordinate3*>(coords)->point.getValues(0));
        stopVisibility(action);
    }

    inherited::doAction(action);
}

void SoFCIndexedFaceSet::startSelection(SoAction * action)
{
    Gui::SoGLSelectAction *doaction = static_cast<Gui::SoGLSelectAction*>(action);
    const SbViewportRegion& vp = doaction->getViewportRegion();
    int x = vp.getViewportOriginPixels()[0];
    int y = vp.getViewportOriginPixels()[1];
    int w = vp.getViewportSizePixels()[0];
    int h = vp.getViewportSizePixels()[1];

    int bufSize = 5*(this->coordIndex.getNum()/4); // make the buffer big enough
    this->selectBuf = new GLuint[bufSize];

    SbMatrix view = SoViewingMatrixElement::get(action->getState());
    SbMatrix proj = SoProjectionMatrixElement::get(action->getState());

    glSelectBuffer(bufSize, selectBuf);
    glRenderMode(GL_SELECT);

    glInitNames();
    glPushName(-1);

    //double mp[16];
    GLint viewport[4];
    glGetIntegerv(GL_VIEWPORT,viewport);
    glMatrixMode(GL_PROJECTION);
    //glGetDoublev(GL_PROJECTION_MATRIX ,mp);
    glPushMatrix();
    glLoadIdentity();
    // See https://www.opengl.org/discussion_boards/showthread.php/184308-gluPickMatrix-Implementation?p=1259884&viewfull=1#post1259884
    //gluPickMatrix(x, y, w, h, viewport);
    if (w > 0 && h > 0) {
        glTranslatef((viewport[2] - 2 * (x - viewport[0])) / w, (viewport[3] - 2 * (y - viewport[1])) / h, 0);
        glScalef(viewport[2] / w, viewport[3] / h, 1.0);
    }
    glMultMatrixf(/*mp*/(float*)proj);
    glMatrixMode(GL_MODELVIEW);
    glPushMatrix();
    glLoadMatrixf((float*)view);
}

void SoFCIndexedFaceSet::stopSelection(SoAction * action)
{
    // restoring the original projection matrix
    glPopMatrix();
    glMatrixMode(GL_PROJECTION);
    glPopMatrix();
    glMatrixMode(GL_MODELVIEW);
    glFlush();

    // returning to normal rendering mode
    GLint hits = glRenderMode(GL_RENDER);

    int bufSize = 5*(this->coordIndex.getNum()/4);
    std::vector< std::pair<double,unsigned int> > hit;
    GLint index=0;
    for (GLint ii=0;ii<hits && index<bufSize;ii++) {
        GLint ct = (GLint)selectBuf[index];
        hit.push_back(std::pair<double,unsigned int>
            (selectBuf[index+1]/4294967295.0,selectBuf[index+3]));
        index = index+ct+3;
    }

    delete [] selectBuf;
    selectBuf = 0;
    bool sorted = true;
    if(sorted) std::sort(hit.begin(),hit.end());

    Gui::SoGLSelectAction *doaction = static_cast<Gui::SoGLSelectAction*>(action);
    doaction->indices.reserve(hit.size());
    for (GLint ii=0;ii<hits;ii++) {
        doaction->indices.push_back(hit[ii].second);
    }
}

void SoFCIndexedFaceSet::renderSelectionGeometry(const SbVec3f * coords3d)
{
    int numfaces = this->coordIndex.getNum()/4;
    const int32_t * cindices = this->coordIndex.getValues(0);

    int fcnt=0;
    int32_t v1, v2, v3;
    for (int index=0; index<numfaces;index++,cindices++) {
        glLoadName(fcnt);
        glBegin(GL_TRIANGLES);
            v1 = *cindices++;
            glVertex3fv((const GLfloat*)(coords3d + v1));
            v2 = *cindices++;
            glVertex3fv((const GLfloat*)(coords3d + v2));
            v3 = *cindices++;
            glVertex3fv((const GLfloat*)(coords3d + v3));
        glEnd();
        fcnt++;
    }
}

void SoFCIndexedFaceSet::startVisibility(SoAction * action)
{
    SbMatrix view = SoViewingMatrixElement::get(action->getState());
    SbMatrix proj = SoProjectionMatrixElement::get(action->getState());

    glMatrixMode(GL_PROJECTION);
    glPushMatrix();
    glLoadIdentity();
    glMultMatrixf((float*)proj);
    glMatrixMode(GL_MODELVIEW);
    glPushMatrix();
    glLoadMatrixf((float*)view);
}

void SoFCIndexedFaceSet::stopVisibility(SoAction * /*action*/)
{
    // restoring the original projection matrix
    glPopMatrix();
    glMatrixMode(GL_PROJECTION);
    glPopMatrix();
    glMatrixMode(GL_MODELVIEW);
    glFlush();
}

void SoFCIndexedFaceSet::renderVisibleFaces(const SbVec3f * coords3d)
{
    //GLint redBits, greenBits, blueBits;

    //glGetIntegerv (GL_RED_BITS, &redBits);
    //glGetIntegerv (GL_GREEN_BITS, &greenBits);
    //glGetIntegerv (GL_BLUE_BITS, &blueBits);
    glDisable (GL_BLEND);
    glDisable (GL_DITHER);
    glDisable (GL_FOG);
    glDisable (GL_LIGHTING);
    glDisable (GL_TEXTURE_1D);
    glDisable (GL_TEXTURE_2D);
    glShadeModel (GL_FLAT);

    uint32_t numfaces = this->coordIndex.getNum()/4;
    const int32_t * cindices = this->coordIndex.getValues(0);

    int32_t v1, v2, v3;
    for (uint32_t index=0; index<numfaces;index++,cindices++) {
        glBegin(GL_TRIANGLES);
            float t;
            SbColor c;
            c.setPackedValue(index<<8,t);
            glColor3f(c[0],c[1],c[2]);
            v1 = *cindices++;
            glVertex3fv((const GLfloat*)(coords3d + v1));
            v2 = *cindices++;
            glVertex3fv((const GLfloat*)(coords3d + v2));
            v3 = *cindices++;
            glVertex3fv((const GLfloat*)(coords3d + v3));
        glEnd();
    }
}