- Qt 5.5
- Qt Widgets
- Boxes
- scene.cpp Example File
- Qt 5.5.1 Reference Documentation

# scene.cpp Example File

graphicsview/boxes/scene.cpp

    /****************************************************************************
    **
    ** Copyright (C) 2015 The Qt Company Ltd.
    ** Contact: http://www.qt.io/licensing/
    **
    ** This file is part of the demonstration applications of the Qt Toolkit.
    **
    ** $QT_BEGIN_LICENSE:LGPL21$
    ** Commercial License Usage
    ** Licensees holding valid commercial Qt licenses may use this file in
    ** accordance with the commercial license agreement provided with the
    ** Software or, alternatively, in accordance with the terms contained in
    ** a written agreement between you and The Qt Company. For licensing terms
    ** and conditions see http://www.qt.io/terms-conditions. For further
    ** information use the contact form at http://www.qt.io/contact-us.
    **
    ** GNU Lesser General Public License Usage
    ** Alternatively, this file may be used under the terms of the GNU Lesser
    ** General Public License version 2.1 or version 3 as published by the Free
    ** Software Foundation and appearing in the file LICENSE.LGPLv21 and
    ** LICENSE.LGPLv3 included in the packaging of this file. Please review the
    ** following information to ensure the GNU Lesser General Public License
    ** requirements will be met: https://www.gnu.org/licenses/lgpl.html and
    ** http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
    **
    ** As a special exception, The Qt Company gives you certain additional
    ** rights. These rights are described in The Qt Company LGPL Exception
    ** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
    **
    ** $QT_END_LICENSE$
    **
    ****************************************************************************/

    #include <QDebug>
    #include "scene.h"
    #include <QtGui/qmatrix4x4.h>
    #include <QtGui/qvector3d.h>
    #include <cmath>

    #include "3rdparty/fbm.h"

    void checkGLErrors(const QString& prefix)
    {
        switch (glGetError()) {
        case GL_NO_ERROR:
            //qDebug() << prefix << tr("No error.");
            break;
        case GL_INVALID_ENUM:
            qDebug() << prefix << QObject::tr("Invalid enum.");
            break;
        case GL_INVALID_VALUE:
            qDebug() << prefix << QObject::tr("Invalid value.");
            break;
        case GL_INVALID_OPERATION:
            qDebug() << prefix << QObject::tr("Invalid operation.");
            break;
        case GL_STACK_OVERFLOW:
            qDebug() << prefix << QObject::tr("Stack overflow.");
            break;
        case GL_STACK_UNDERFLOW:
            qDebug() << prefix << QObject::tr("Stack underflow.");
            break;
        case GL_OUT_OF_MEMORY:
            qDebug() << prefix << QObject::tr("Out of memory.");
            break;
        default:
            qDebug() << prefix << QObject::tr("Unknown error.");
            break;
        }
    }

    //============================================================================//
    //                                  ColorEdit                                 //
    //============================================================================//

    ColorEdit::ColorEdit(QRgb initialColor, int id)
        : m_color(initialColor), m_id(id)
    {
        QHBoxLayout *layout = new QHBoxLayout;
        setLayout(layout);
        layout->setContentsMargins(0, 0, 0, 0);

        m_lineEdit = new QLineEdit(QString::number(m_color, 16));
        layout->addWidget(m_lineEdit);

        m_button = new QFrame;
        QPalette palette = m_button->palette();
        palette.setColor(QPalette::Window, QColor(m_color));
        m_button->setPalette(palette);
        m_button->setAutoFillBackground(true);
        m_button->setMinimumSize(32, 0);
        m_button->setSizePolicy(QSizePolicy::Fixed, QSizePolicy::Preferred);
        m_button->setFrameStyle(QFrame::StyledPanel | QFrame::Sunken);
        layout->addWidget(m_button);

        connect(m_lineEdit, SIGNAL(editingFinished()), this, SLOT(editDone()));
    }

    void ColorEdit::editDone()
    {
        bool ok;
        QRgb newColor = m_lineEdit->text().toUInt(&ok, 16);
        if (ok)
            setColor(newColor);
    }

    void ColorEdit::mousePressEvent(QMouseEvent *event)
    {
        if (event->button() == Qt::LeftButton) {
            QColor color(m_color);
            QColorDialog dialog(color, 0);
            dialog.setOption(QColorDialog::ShowAlphaChannel, true);
    // The ifdef block is a workaround for the beta, TODO: remove when bug 238525 is fixed
    #ifdef Q_DEAD_CODE_FROM_QT4_MAC
            dialog.setOption(QColorDialog::DontUseNativeDialog, true);
    #endif
            dialog.move(280, 120);
            if (dialog.exec() == QDialog::Rejected)
                return;
            QRgb newColor = dialog.selectedColor().rgba();
            if (newColor == m_color)
                return;
            setColor(newColor);
        }
    }

    void ColorEdit::setColor(QRgb color)
    {
        m_color = color;
        m_lineEdit->setText(QString::number(m_color, 16)); // "Clean up" text
        QPalette palette = m_button->palette();
        palette.setColor(QPalette::Window, QColor(m_color));
        m_button->setPalette(palette);
        emit colorChanged(m_color, m_id);
    }

    //============================================================================//
    //                                  FloatEdit                                 //
    //============================================================================//

    FloatEdit::FloatEdit(float initialValue, int id)
        : m_value(initialValue), m_id(id)
    {
        QHBoxLayout *layout = new QHBoxLayout;
        setLayout(layout);
        layout->setContentsMargins(0, 0, 0, 0);

        m_lineEdit = new QLineEdit(QString::number(m_value));
        layout->addWidget(m_lineEdit);

        connect(m_lineEdit, SIGNAL(editingFinished()), this, SLOT(editDone()));
    }

    void FloatEdit::editDone()
    {
        bool ok;
        float newValue = m_lineEdit->text().toFloat(&ok);
        if (ok) {
            m_value = newValue;
            m_lineEdit->setText(QString::number(m_value)); // "Clean up" text
            emit valueChanged(m_value, m_id);
        }
    }

    //============================================================================//
    //                           TwoSidedGraphicsWidget                           //
    //============================================================================//

    TwoSidedGraphicsWidget::TwoSidedGraphicsWidget(QGraphicsScene *scene)
        : QObject(scene)
        , m_current(0)
        , m_angle(0)
        , m_delta(0)
    {
        for (int i = 0; i < 2; ++i)
            m_proxyWidgets[i] = 0;
    }

    void TwoSidedGraphicsWidget::setWidget(int index, QWidget *widget)
    {
        if (index < 0 || index >= 2)
        {
            qWarning("TwoSidedGraphicsWidget::setWidget: Index out of bounds, index == %d", index);
            return;
        }

        GraphicsWidget *proxy = new GraphicsWidget;
        proxy->setWidget(widget);

        if (m_proxyWidgets[index])
            delete m_proxyWidgets[index];
        m_proxyWidgets[index] = proxy;

        proxy->setCacheMode(QGraphicsItem::ItemCoordinateCache);
        proxy->setZValue(1e30); // Make sure the dialog is drawn on top of all other (OpenGL) items

        if (index != m_current)
            proxy->setVisible(false);

        qobject_cast<QGraphicsScene *>(parent())->addItem(proxy);
    }

    QWidget *TwoSidedGraphicsWidget::widget(int index)
    {
        if (index < 0 || index >= 2)
        {
            qWarning("TwoSidedGraphicsWidget::widget: Index out of bounds, index == %d", index);
            return 0;
        }
        return m_proxyWidgets[index]->widget();
    }

    void TwoSidedGraphicsWidget::flip()
    {
        m_delta = (m_current == 0 ? 9 : -9);
        animateFlip();
    }

    void TwoSidedGraphicsWidget::animateFlip()
    {
        m_angle += m_delta;
        if (m_angle == 90) {
            int old = m_current;
            m_current ^= 1;
            m_proxyWidgets[old]->setVisible(false);
            m_proxyWidgets[m_current]->setVisible(true);
            m_proxyWidgets[m_current]->setGeometry(m_proxyWidgets[old]->geometry());
        }

        QRectF r = m_proxyWidgets[m_current]->boundingRect();
        m_proxyWidgets[m_current]->setTransform(QTransform()
            .translate(r.width() / 2, r.height() / 2)
            .rotate(m_angle - 180 * m_current, Qt::YAxis)
            .translate(-r.width() / 2, -r.height() / 2));

        if ((m_current == 0 && m_angle > 0) || (m_current == 1 && m_angle < 180))
            QTimer::singleShot(25, this, SLOT(animateFlip()));
    }

    QVariant GraphicsWidget::itemChange(GraphicsItemChange change, const QVariant &value)
    {
        if (change == ItemPositionChange && scene()) {
            QRectF rect = boundingRect();
            QPointF pos = value.toPointF();
            QRectF sceneRect = scene()->sceneRect();
            if (pos.x() + rect.left() < sceneRect.left())
                pos.setX(sceneRect.left() - rect.left());
            else if (pos.x() + rect.right() >= sceneRect.right())
                pos.setX(sceneRect.right() - rect.right());
            if (pos.y() + rect.top() < sceneRect.top())
                pos.setY(sceneRect.top() - rect.top());
            else if (pos.y() + rect.bottom() >= sceneRect.bottom())
                pos.setY(sceneRect.bottom() - rect.bottom());
            return pos;
        }
        return QGraphicsProxyWidget::itemChange(change, value);
    }

    void GraphicsWidget::resizeEvent(QGraphicsSceneResizeEvent *event)
    {
        setCacheMode(QGraphicsItem::NoCache);
        setCacheMode(QGraphicsItem::ItemCoordinateCache);
        QGraphicsProxyWidget::resizeEvent(event);
    }

    void GraphicsWidget::paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget)
    {
        painter->setRenderHint(QPainter::Antialiasing, false);
        QGraphicsProxyWidget::paint(painter, option, widget);
        //painter->setRenderHint(QPainter::Antialiasing, true);
    }

    //============================================================================//
    //                             RenderOptionsDialog                            //
    //============================================================================//

    RenderOptionsDialog::RenderOptionsDialog()
        : QDialog(0, Qt::CustomizeWindowHint | Qt::WindowTitleHint)
    {
        setWindowOpacity(0.75);
        setWindowTitle(tr("Options (double click to flip)"));
        QGridLayout *layout = new QGridLayout;
        setLayout(layout);
        layout->setColumnStretch(1, 1);

        int row = 0;

        QCheckBox *check = new QCheckBox(tr("Dynamic cube map"));
        check->setCheckState(Qt::Unchecked);
        // Dynamic cube maps are only enabled when multi-texturing and render to texture are available.
        check->setEnabled(glActiveTexture && glGenFramebuffersEXT);
        connect(check, SIGNAL(stateChanged(int)), this, SIGNAL(dynamicCubemapToggled(int)));
        layout->addWidget(check, 0, 0, 1, 2);
        ++row;

        QPalette palette;

        // Load all .par files
        // .par files have a simple syntax for specifying user adjustable uniform variables.
        QSet<QByteArray> uniforms;
        QList<QString> filter = QStringList("*.par");
        QList<QFileInfo> files = QDir(":/res/boxes/").entryInfoList(filter, QDir::Files | QDir::Readable);

        foreach (QFileInfo fileInfo, files) {
            QFile file(fileInfo.absoluteFilePath());
            if (file.open(QIODevice::ReadOnly)) {
                while (!file.atEnd()) {
                    QList<QByteArray> tokens = file.readLine().simplified().split(' ');
                    QList<QByteArray>::const_iterator it = tokens.begin();
                    if (it == tokens.end())
                        continue;
                    QByteArray type = *it;
                    if (++it == tokens.end())
                        continue;
                    QByteArray name = *it;
                    bool singleElement = (tokens.size() == 3); // type, name and one value
                    char counter[10] = "000000000";
                    int counterPos = 8; // position of last digit
                    while (++it != tokens.end()) {
                        m_parameterNames << name;
                        if (!singleElement) {
                            m_parameterNames.back() += "[";
                            m_parameterNames.back() += counter + counterPos;
                            m_parameterNames.back() += "]";
                            int j = 8; // position of last digit
                            ++counter[j];
                            while (j > 0 && counter[j] > '9') {
                                counter[j] = '0';
                                ++counter[--j];
                            }
                            if (j < counterPos)
                                counterPos = j;
                        }

                        if (type == "color") {
                            layout->addWidget(new QLabel(m_parameterNames.back()));
                            bool ok;
                            ColorEdit *colorEdit = new ColorEdit(it->toUInt(&ok, 16), m_parameterNames.size() - 1);
                            m_parameterEdits << colorEdit;
                            layout->addWidget(colorEdit);
                            connect(colorEdit, SIGNAL(colorChanged(QRgb,int)), this, SLOT(setColorParameter(QRgb,int)));
                            ++row;
                        } else if (type == "float") {
                            layout->addWidget(new QLabel(m_parameterNames.back()));
                            bool ok;
                            FloatEdit *floatEdit = new FloatEdit(it->toFloat(&ok), m_parameterNames.size() - 1);
                            m_parameterEdits << floatEdit;
                            layout->addWidget(floatEdit);
                            connect(floatEdit, SIGNAL(valueChanged(float,int)), this, SLOT(setFloatParameter(float,int)));
                            ++row;
                        }
                    }
                }
                file.close();
            }
        }

        layout->addWidget(new QLabel(tr("Texture:")));
        m_textureCombo = new QComboBox;
        connect(m_textureCombo, SIGNAL(currentIndexChanged(int)), this, SIGNAL(textureChanged(int)));
        layout->addWidget(m_textureCombo);
        ++row;

        layout->addWidget(new QLabel(tr("Shader:")));
        m_shaderCombo = new QComboBox;
        connect(m_shaderCombo, SIGNAL(currentIndexChanged(int)), this, SIGNAL(shaderChanged(int)));
        layout->addWidget(m_shaderCombo);
        ++row;

        layout->setRowStretch(row, 1);
    }

    int RenderOptionsDialog::addTexture(const QString &name)
    {
        m_textureCombo->addItem(name);
        return m_textureCombo->count() - 1;
    }

    int RenderOptionsDialog::addShader(const QString &name)
    {
        m_shaderCombo->addItem(name);
        return m_shaderCombo->count() - 1;
    }

    void RenderOptionsDialog::emitParameterChanged()
    {
        foreach (ParameterEdit *edit, m_parameterEdits)
            edit->emitChange();
    }

    void RenderOptionsDialog::setColorParameter(QRgb color, int id)
    {
        emit colorParameterChanged(m_parameterNames[id], color);
    }

    void RenderOptionsDialog::setFloatParameter(float value, int id)
    {
        emit floatParameterChanged(m_parameterNames[id], value);
    }

    void RenderOptionsDialog::mouseDoubleClickEvent(QMouseEvent *event)
    {
        if (event->button() == Qt::LeftButton)
            emit doubleClicked();
    }

    //============================================================================//
    //                                 ItemDialog                                 //
    //============================================================================//

    ItemDialog::ItemDialog()
        : QDialog(0, Qt::CustomizeWindowHint | Qt::WindowTitleHint)
    {
        setWindowTitle(tr("Items (double click to flip)"));
        setWindowOpacity(0.75);
        resize(160, 100);

        QVBoxLayout *layout = new QVBoxLayout;
        setLayout(layout);
        QPushButton *button;

        button = new QPushButton(tr("Add Qt box"));
        layout->addWidget(button);
        connect(button, SIGNAL(clicked()), this, SLOT(triggerNewQtBox()));

        button = new QPushButton(tr("Add circle"));
        layout->addWidget(button);
        connect(button, SIGNAL(clicked()), this, SLOT(triggerNewCircleItem()));

        button = new QPushButton(tr("Add square"));
        layout->addWidget(button);
        connect(button, SIGNAL(clicked()), this, SLOT(triggerNewSquareItem()));

        layout->addStretch(1);
    }

    void ItemDialog::triggerNewQtBox()
    {
        emit newItemTriggered(QtBoxItem);
    }

    void ItemDialog::triggerNewCircleItem()
    {
        emit newItemTriggered(CircleItem);
    }

    void ItemDialog::triggerNewSquareItem()
    {
        emit newItemTriggered(SquareItem);
    }

    void ItemDialog::mouseDoubleClickEvent(QMouseEvent *event)
    {
        if (event->button() == Qt::LeftButton)
            emit doubleClicked();
    }

    //============================================================================//
    //                                    Scene                                   //
    //============================================================================//

    const static char environmentShaderText[] =
        "uniform samplerCube env;"
        "void main() {"
            "gl_FragColor = textureCube(env, gl_TexCoord[1].xyz);"
        "}";

    Scene::Scene(int width, int height, int maxTextureSize)
        : m_distExp(600)
        , m_frame(0)
        , m_maxTextureSize(maxTextureSize)
        , m_currentShader(0)
        , m_currentTexture(0)
        , m_dynamicCubemap(false)
        , m_updateAllCubemaps(true)
        , m_box(0)
        , m_vertexShader(0)
        , m_environmentShader(0)
        , m_environmentProgram(0)
    {
        setSceneRect(0, 0, width, height);

        m_trackBalls[0] = TrackBall(0.05f, QVector3D(0, 1, 0), TrackBall::Sphere);
        m_trackBalls[1] = TrackBall(0.005f, QVector3D(0, 0, 1), TrackBall::Sphere);
        m_trackBalls[2] = TrackBall(0.0f, QVector3D(0, 1, 0), TrackBall::Plane);

        m_renderOptions = new RenderOptionsDialog;
        m_renderOptions->move(20, 120);
        m_renderOptions->resize(m_renderOptions->sizeHint());

        connect(m_renderOptions, SIGNAL(dynamicCubemapToggled(int)), this, SLOT(toggleDynamicCubemap(int)));
        connect(m_renderOptions, SIGNAL(colorParameterChanged(QString,QRgb)), this, SLOT(setColorParameter(QString,QRgb)));
        connect(m_renderOptions, SIGNAL(floatParameterChanged(QString,float)), this, SLOT(setFloatParameter(QString,float)));
        connect(m_renderOptions, SIGNAL(textureChanged(int)), this, SLOT(setTexture(int)));
        connect(m_renderOptions, SIGNAL(shaderChanged(int)), this, SLOT(setShader(int)));

        m_itemDialog = new ItemDialog;
        connect(m_itemDialog, SIGNAL(newItemTriggered(ItemDialog::ItemType)), this, SLOT(newItem(ItemDialog::ItemType)));

        TwoSidedGraphicsWidget *twoSided = new TwoSidedGraphicsWidget(this);
        twoSided->setWidget(0, m_renderOptions);
        twoSided->setWidget(1, m_itemDialog);

        connect(m_renderOptions, SIGNAL(doubleClicked()), twoSided, SLOT(flip()));
        connect(m_itemDialog, SIGNAL(doubleClicked()), twoSided, SLOT(flip()));

        addItem(new QtBox(64, width - 64, height - 64));
        addItem(new QtBox(64, width - 64, 64));
        addItem(new QtBox(64, 64, height - 64));
        addItem(new QtBox(64, 64, 64));

        initGL();

        m_timer = new QTimer(this);
        m_timer->setInterval(20);
        connect(m_timer, SIGNAL(timeout()), this, SLOT(update()));
        m_timer->start();

        m_time.start();
    }

    Scene::~Scene()
    {
        if (m_box)
            delete m_box;
        foreach (GLTexture *texture, m_textures)
            if (texture) delete texture;
        if (m_mainCubemap)
            delete m_mainCubemap;
        foreach (QGLShaderProgram *program, m_programs)
            if (program) delete program;
        if (m_vertexShader)
            delete m_vertexShader;
        foreach (QGLShader *shader, m_fragmentShaders)
            if (shader) delete shader;
        foreach (GLRenderTargetCube *rt, m_cubemaps)
            if (rt) delete rt;
        if (m_environmentShader)
            delete m_environmentShader;
        if (m_environmentProgram)
            delete m_environmentProgram;
    }

    void Scene::initGL()
    {
        m_box = new GLRoundedBox(0.25f, 1.0f, 10);

        m_vertexShader = new QGLShader(QGLShader::Vertex);
        m_vertexShader->compileSourceFile(QLatin1String(":/res/boxes/basic.vsh"));

        QStringList list;
        list << ":/res/boxes/cubemap_posx.jpg" << ":/res/boxes/cubemap_negx.jpg" << ":/res/boxes/cubemap_posy.jpg"
             << ":/res/boxes/cubemap_negy.jpg" << ":/res/boxes/cubemap_posz.jpg" << ":/res/boxes/cubemap_negz.jpg";
        m_environment = new GLTextureCube(list, qMin(1024, m_maxTextureSize));
        m_environmentShader = new QGLShader(QGLShader::Fragment);
        m_environmentShader->compileSourceCode(environmentShaderText);
        m_environmentProgram = new QGLShaderProgram;
        m_environmentProgram->addShader(m_vertexShader);
        m_environmentProgram->addShader(m_environmentShader);
        m_environmentProgram->link();

        const int NOISE_SIZE = 128; // for a different size, B and BM in fbm.c must also be changed
        m_noise = new GLTexture3D(NOISE_SIZE, NOISE_SIZE, NOISE_SIZE);
        QRgb *data = new QRgb[NOISE_SIZE * NOISE_SIZE * NOISE_SIZE];
        memset(data, 0, NOISE_SIZE * NOISE_SIZE * NOISE_SIZE * sizeof(QRgb));
        QRgb *p = data;
        float pos[3];
        for (int k = 0; k < NOISE_SIZE; ++k) {
            pos[2] = k * (0x20 / (float)NOISE_SIZE);
            for (int j = 0; j < NOISE_SIZE; ++j) {
                for (int i = 0; i < NOISE_SIZE; ++i) {
                    for (int byte = 0; byte < 4; ++byte) {
                        pos[0] = (i + (byte & 1) * 16) * (0x20 / (float)NOISE_SIZE);
                        pos[1] = (j + (byte & 2) * 8) * (0x20 / (float)NOISE_SIZE);
                        *p |= (int)(128.0f * (noise3(pos) + 1.0f)) << (byte * 8);
                    }
                    ++p;
                }
            }
        }
        m_noise->load(NOISE_SIZE, NOISE_SIZE, NOISE_SIZE, data);
        delete[] data;

        m_mainCubemap = new GLRenderTargetCube(512);

        QStringList filter;
        QList<QFileInfo> files;

        // Load all .png files as textures
        m_currentTexture = 0;
        filter = QStringList("*.png");
        files = QDir(":/res/boxes/").entryInfoList(filter, QDir::Files | QDir::Readable);

        foreach (QFileInfo file, files) {
            GLTexture *texture = new GLTexture2D(file.absoluteFilePath(), qMin(256, m_maxTextureSize), qMin(256, m_maxTextureSize));
            if (texture->failed()) {
                delete texture;
                continue;
            }
            m_textures << texture;
            m_renderOptions->addTexture(file.baseName());
        }

        if (m_textures.size() == 0)
            m_textures << new GLTexture2D(qMin(64, m_maxTextureSize), qMin(64, m_maxTextureSize));

        // Load all .fsh files as fragment shaders
        m_currentShader = 0;
        filter = QStringList("*.fsh");
        files = QDir(":/res/boxes/").entryInfoList(filter, QDir::Files | QDir::Readable);
        foreach (QFileInfo file, files) {
            QGLShaderProgram *program = new QGLShaderProgram;
            QGLShader* shader = new QGLShader(QGLShader::Fragment);
            shader->compileSourceFile(file.absoluteFilePath());
            // The program does not take ownership over the shaders, so store them in a vector so they can be deleted afterwards.
            program->addShader(m_vertexShader);
            program->addShader(shader);
            if (!program->link()) {
                qWarning("Failed to compile and link shader program");
                qWarning("Vertex shader log:");
                qWarning() << m_vertexShader->log();
                qWarning() << "Fragment shader log ( file =" << file.absoluteFilePath() << "):";
                qWarning() << shader->log();
                qWarning("Shader program log:");
                qWarning() << program->log();

                delete shader;
                delete program;
                continue;
            }

            m_fragmentShaders << shader;
            m_programs << program;
            m_renderOptions->addShader(file.baseName());

            program->bind();
            m_cubemaps << ((program->uniformLocation("env") != -1) ? new GLRenderTargetCube(qMin(256, m_maxTextureSize)) : 0);
            program->release();
        }

        if (m_programs.size() == 0)
            m_programs << new QGLShaderProgram;

        m_renderOptions->emitParameterChanged();
    }

    static void loadMatrix(const QMatrix4x4& m)
    {
        // static to prevent glLoadMatrixf to fail on certain drivers
        static GLfloat mat[16];
        const float *data = m.constData();
        for (int index = 0; index < 16; ++index)
            mat[index] = data[index];
        glLoadMatrixf(mat);
    }

    // If one of the boxes should not be rendered, set excludeBox to its index.
    // If the main box should not be rendered, set excludeBox to -1.
    void Scene::renderBoxes(const QMatrix4x4 &view, int excludeBox)
    {
        QMatrix4x4 invView = view.inverted();

        // If multi-texturing is supported, use three saplers.
        if (glActiveTexture) {
            glActiveTexture(GL_TEXTURE0);
            m_textures[m_currentTexture]->bind();
            glActiveTexture(GL_TEXTURE2);
            m_noise->bind();
            glActiveTexture(GL_TEXTURE1);
        } else {
            m_textures[m_currentTexture]->bind();
        }

        glDisable(GL_LIGHTING);
        glDisable(GL_CULL_FACE);

        QMatrix4x4 viewRotation(view);
        viewRotation(3, 0) = viewRotation(3, 1) = viewRotation(3, 2) = 0.0f;
        viewRotation(0, 3) = viewRotation(1, 3) = viewRotation(2, 3) = 0.0f;
        viewRotation(3, 3) = 1.0f;
        loadMatrix(viewRotation);
        glScalef(20.0f, 20.0f, 20.0f);

        // Don't render the environment if the environment texture can't be set for the correct sampler.
        if (glActiveTexture) {
            m_environment->bind();
            m_environmentProgram->bind();
            m_environmentProgram->setUniformValue("tex", GLint(0));
            m_environmentProgram->setUniformValue("env", GLint(1));
            m_environmentProgram->setUniformValue("noise", GLint(2));
            m_box->draw();
            m_environmentProgram->release();
            m_environment->unbind();
        }

        loadMatrix(view);

        glEnable(GL_CULL_FACE);
        glEnable(GL_LIGHTING);

        for (int i = 0; i < m_programs.size(); ++i) {
            if (i == excludeBox)
                continue;

            glPushMatrix();
            QMatrix4x4 m;
            m.rotate(m_trackBalls[1].rotation());
            glMultMatrixf(m.constData());

            glRotatef(360.0f * i / m_programs.size(), 0.0f, 0.0f, 1.0f);
            glTranslatef(2.0f, 0.0f, 0.0f);
            glScalef(0.3f, 0.6f, 0.6f);

            if (glActiveTexture) {
                if (m_dynamicCubemap && m_cubemaps[i])
                    m_cubemaps[i]->bind();
                else
                    m_environment->bind();
            }
            m_programs[i]->bind();
            m_programs[i]->setUniformValue("tex", GLint(0));
            m_programs[i]->setUniformValue("env", GLint(1));
            m_programs[i]->setUniformValue("noise", GLint(2));
            m_programs[i]->setUniformValue("view", view);
            m_programs[i]->setUniformValue("invView", invView);
            m_box->draw();
            m_programs[i]->release();

            if (glActiveTexture) {
                if (m_dynamicCubemap && m_cubemaps[i])
                    m_cubemaps[i]->unbind();
                else
                    m_environment->unbind();
            }
            glPopMatrix();
        }

        if (-1 != excludeBox) {
            QMatrix4x4 m;
            m.rotate(m_trackBalls[0].rotation());
            glMultMatrixf(m.constData());

            if (glActiveTexture) {
                if (m_dynamicCubemap)
                    m_mainCubemap->bind();
                else
                    m_environment->bind();
            }

            m_programs[m_currentShader]->bind();
            m_programs[m_currentShader]->setUniformValue("tex", GLint(0));
            m_programs[m_currentShader]->setUniformValue("env", GLint(1));
            m_programs[m_currentShader]->setUniformValue("noise", GLint(2));
            m_programs[m_currentShader]->setUniformValue("view", view);
            m_programs[m_currentShader]->setUniformValue("invView", invView);
            m_box->draw();
            m_programs[m_currentShader]->release();

            if (glActiveTexture) {
                if (m_dynamicCubemap)
                    m_mainCubemap->unbind();
                else
                    m_environment->unbind();
            }
        }

        if (glActiveTexture) {
            glActiveTexture(GL_TEXTURE2);
            m_noise->unbind();
            glActiveTexture(GL_TEXTURE0);
        }
        m_textures[m_currentTexture]->unbind();
    }

    void Scene::setStates()
    {
        //glClearColor(0.25f, 0.25f, 0.5f, 1.0f);

        glEnable(GL_DEPTH_TEST);
        glEnable(GL_CULL_FACE);
        glEnable(GL_LIGHTING);
        //glEnable(GL_COLOR_MATERIAL);
        glEnable(GL_TEXTURE_2D);
        glEnable(GL_NORMALIZE);

        glMatrixMode(GL_PROJECTION);
        glPushMatrix();
        glLoadIdentity();

        glMatrixMode(GL_MODELVIEW);
        glPushMatrix();
        glLoadIdentity();

        setLights();

        float materialSpecular[] = {0.5f, 0.5f, 0.5f, 1.0f};
        glMaterialfv(GL_FRONT_AND_BACK, GL_SPECULAR, materialSpecular);
        glMaterialf(GL_FRONT_AND_BACK, GL_SHININESS, 32.0f);
    }

    void Scene::setLights()
    {
        glColorMaterial(GL_FRONT_AND_BACK, GL_AMBIENT_AND_DIFFUSE);
        //float lightColour[] = {1.0f, 1.0f, 1.0f, 1.0f};
        float lightDir[] = {0.0f, 0.0f, 1.0f, 0.0f};
        //glLightfv(GL_LIGHT0, GL_DIFFUSE, lightColour);
        //glLightfv(GL_LIGHT0, GL_SPECULAR, lightColour);
        glLightfv(GL_LIGHT0, GL_POSITION, lightDir);
        glLightModelf(GL_LIGHT_MODEL_LOCAL_VIEWER, 1.0f);
        glEnable(GL_LIGHT0);
    }

    void Scene::defaultStates()
    {
        //glClearColor(0.0f, 0.0f, 0.0f, 0.0f);

        glDisable(GL_DEPTH_TEST);
        glDisable(GL_CULL_FACE);
        glDisable(GL_LIGHTING);
        //glDisable(GL_COLOR_MATERIAL);
        glDisable(GL_TEXTURE_2D);
        glDisable(GL_LIGHT0);
        glDisable(GL_NORMALIZE);

        glMatrixMode(GL_MODELVIEW);
        glPopMatrix();

        glMatrixMode(GL_PROJECTION);
        glPopMatrix();

        glLightModelf(GL_LIGHT_MODEL_LOCAL_VIEWER, 0.0f);
        float defaultMaterialSpecular[] = {0.0f, 0.0f, 0.0f, 1.0f};
        glMaterialfv(GL_FRONT_AND_BACK, GL_SPECULAR, defaultMaterialSpecular);
        glMaterialf(GL_FRONT_AND_BACK, GL_SHININESS, 0.0f);
    }

    void Scene::renderCubemaps()
    {
        // To speed things up, only update the cubemaps for the small cubes every N frames.
        const int N = (m_updateAllCubemaps ? 1 : 3);

        QMatrix4x4 mat;
        GLRenderTargetCube::getProjectionMatrix(mat, 0.1f, 100.0f);

        glMatrixMode(GL_PROJECTION);
        glPushMatrix();
        loadMatrix(mat);

        glMatrixMode(GL_MODELVIEW);
        glPushMatrix();

        QVector3D center;

        for (int i = m_frame % N; i < m_cubemaps.size(); i += N) {
            if (0 == m_cubemaps[i])
                continue;

            float angle = 2.0f * PI * i / m_cubemaps.size();

            center = m_trackBalls[1].rotation().rotatedVector(QVector3D(std::cos(angle), std::sin(angle), 0.0f));

            for (int face = 0; face < 6; ++face) {
                m_cubemaps[i]->begin(face);

                GLRenderTargetCube::getViewMatrix(mat, face);
                QVector4D v = QVector4D(-center.x(), -center.y(), -center.z(), 1.0);
                mat.setColumn(3, mat * v);

                glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
                renderBoxes(mat, i);

                m_cubemaps[i]->end();
            }
        }

        for (int face = 0; face < 6; ++face) {
            m_mainCubemap->begin(face);
            GLRenderTargetCube::getViewMatrix(mat, face);

            glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
            renderBoxes(mat, -1);

            m_mainCubemap->end();
        }

        glPopMatrix();

        glMatrixMode(GL_PROJECTION);
        glPopMatrix();

        m_updateAllCubemaps = false;
    }

    void Scene::drawBackground(QPainter *painter, const QRectF &)
    {
        float width = float(painter->device()->width());
        float height = float(painter->device()->height());

        painter->beginNativePainting();
        setStates();

        if (m_dynamicCubemap)
            renderCubemaps();

        glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

        glMatrixMode(GL_PROJECTION);
        qgluPerspective(60.0, width / height, 0.01, 15.0);

        glMatrixMode(GL_MODELVIEW);

        QMatrix4x4 view;
        view.rotate(m_trackBalls[2].rotation());
        view(2, 3) -= 2.0f * std::exp(m_distExp / 1200.0f);
        renderBoxes(view);

        defaultStates();
        ++m_frame;

        painter->endNativePainting();
    }

    QPointF Scene::pixelPosToViewPos(const QPointF& p)
    {
        return QPointF(2.0 * float(p.x()) / width() - 1.0,
                       1.0 - 2.0 * float(p.y()) / height());
    }

    void Scene::mouseMoveEvent(QGraphicsSceneMouseEvent *event)
    {
        QGraphicsScene::mouseMoveEvent(event);
        if (event->isAccepted())
            return;

        if (event->buttons() & Qt::LeftButton) {
            m_trackBalls[0].move(pixelPosToViewPos(event->scenePos()), m_trackBalls[2].rotation().conjugate());
            event->accept();
        } else {
            m_trackBalls[0].release(pixelPosToViewPos(event->scenePos()), m_trackBalls[2].rotation().conjugate());
        }

        if (event->buttons() & Qt::RightButton) {
            m_trackBalls[1].move(pixelPosToViewPos(event->scenePos()), m_trackBalls[2].rotation().conjugate());
            event->accept();
        } else {
            m_trackBalls[1].release(pixelPosToViewPos(event->scenePos()), m_trackBalls[2].rotation().conjugate());
        }

        if (event->buttons() & Qt::MidButton) {
            m_trackBalls[2].move(pixelPosToViewPos(event->scenePos()), QQuaternion());
            event->accept();
        } else {
            m_trackBalls[2].release(pixelPosToViewPos(event->scenePos()), QQuaternion());
        }
    }

    void Scene::mousePressEvent(QGraphicsSceneMouseEvent *event)
    {
        QGraphicsScene::mousePressEvent(event);
        if (event->isAccepted())
            return;

        if (event->buttons() & Qt::LeftButton) {
            m_trackBalls[0].push(pixelPosToViewPos(event->scenePos()), m_trackBalls[2].rotation().conjugate());
            event->accept();
        }

        if (event->buttons() & Qt::RightButton) {
            m_trackBalls[1].push(pixelPosToViewPos(event->scenePos()), m_trackBalls[2].rotation().conjugate());
            event->accept();
        }

        if (event->buttons() & Qt::MidButton) {
            m_trackBalls[2].push(pixelPosToViewPos(event->scenePos()), QQuaternion());
            event->accept();
        }
    }

    void Scene::mouseReleaseEvent(QGraphicsSceneMouseEvent *event)
    {
        QGraphicsScene::mouseReleaseEvent(event);
        if (event->isAccepted())
            return;

        if (event->button() == Qt::LeftButton) {
            m_trackBalls[0].release(pixelPosToViewPos(event->scenePos()), m_trackBalls[2].rotation().conjugate());
            event->accept();
        }

        if (event->button() == Qt::RightButton) {
            m_trackBalls[1].release(pixelPosToViewPos(event->scenePos()), m_trackBalls[2].rotation().conjugate());
            event->accept();
        }

        if (event->button() == Qt::MidButton) {
            m_trackBalls[2].release(pixelPosToViewPos(event->scenePos()), QQuaternion());
            event->accept();
        }
    }

    void Scene::wheelEvent(QGraphicsSceneWheelEvent * event)
    {
        QGraphicsScene::wheelEvent(event);
        if (!event->isAccepted()) {
            m_distExp += event->delta();
            if (m_distExp < -8 * 120)
                m_distExp = -8 * 120;
            if (m_distExp > 10 * 120)
                m_distExp = 10 * 120;
            event->accept();
        }
    }

    void Scene::setShader(int index)
    {
        if (index >= 0 && index < m_fragmentShaders.size())
            m_currentShader = index;
    }

    void Scene::setTexture(int index)
    {
        if (index >= 0 && index < m_textures.size())
            m_currentTexture = index;
    }

    void Scene::toggleDynamicCubemap(int state)
    {
        if ((m_dynamicCubemap = (state == Qt::Checked)))
            m_updateAllCubemaps = true;
    }

    void Scene::setColorParameter(const QString &name, QRgb color)
    {
        // set the color in all programs
        foreach (QGLShaderProgram *program, m_programs) {
            program->bind();
            program->setUniformValue(program->uniformLocation(name), QColor(color));
            program->release();
        }
    }

    void Scene::setFloatParameter(const QString &name, float value)
    {
        // set the color in all programs
        foreach (QGLShaderProgram *program, m_programs) {
            program->bind();
            program->setUniformValue(program->uniformLocation(name), value);
            program->release();
        }
    }

    void Scene::newItem(ItemDialog::ItemType type)
    {
        QSize size = sceneRect().size().toSize();
        switch (type) {
        case ItemDialog::QtBoxItem:
            addItem(new QtBox(64, rand() % (size.width() - 64) + 32, rand() % (size.height() - 64) + 32));
            break;
        case ItemDialog::CircleItem:
            addItem(new CircleItem(64, rand() % (size.width() - 64) + 32, rand() % (size.height() - 64) + 32));
            break;
        case ItemDialog::SquareItem:
            addItem(new SquareItem(64, rand() % (size.width() - 64) + 32, rand() % (size.height() - 64) + 32));
            break;
        default:
            break;
        }
    }