scene.cpp Example File
demos/boxes/scene.cpp

 /****************************************************************************
 **
 ** Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies).
 ** All rights reserved.
 ** Contact: Nokia Corporation (qt-info@nokia.com)
 **
 ** This file is part of the demonstration applications of the Qt Toolkit.
 **
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 ** accordance with the Qt Commercial License Agreement provided with the
 ** Software or, alternatively, in accordance with the terms contained in
 ** a written agreement between you and Nokia.
 **
 ** 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 as published by the Free Software
 ** Foundation and appearing in the file LICENSE.LGPL included in the
 ** packaging of this file.  Please review the following information to
 ** ensure the GNU Lesser General Public License version 2.1 requirements
 ** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
 **
 ** In addition, as a special exception, Nokia gives you certain additional
 ** rights.  These rights are described in the Nokia Qt LGPL Exception
 ** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
 **
 ** GNU General Public License Usage
 ** Alternatively, this file may be used under the terms of the GNU
 ** General Public License version 3.0 as published by the Free Software
 ** Foundation and appearing in the file LICENSE.GPL included in the
 ** packaging of this file.  Please review the following information to
 ** ensure the GNU General Public License version 3.0 requirements will be
 ** met: http://www.gnu.org/copyleft/gpl.html.
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 #include <QDebug>
 #include "scene.h"
 #include <QtGui/qmatrix4x4.h>
 #include <QtGui/qvector3d.h>

 #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_WS_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 qreal *data = m.constData();
     for (int index = 0; index < 16; ++index)
         mat[index] = data[index];
     glLoadMatrixf(mat);
 }

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

         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());
         multMatrix(m);

         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(cos(angle), 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);
     gluPerspective(60.0, width / height, 0.01, 15.0);

     glMatrixMode(GL_MODELVIEW);

     QMatrix4x4 view;
     view.rotate(m_trackBalls[2].rotation());
     view(2, 3) -= 2.0f * 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;
     }
 }