/****************************************************************************
**
** Copyright (C) 2014 Digia Plc and/or its subsidiary(-ies).
** Contact: http://www.qt-project.org/legal
**
** This file is part of the demonstration applications of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL$
** 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 Digia.  For licensing terms and
** conditions see http://qt.digia.com/licensing.  For further information
** use the contact form at http://qt.digia.com/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 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, Digia gives you certain additional
** rights.  These rights are described in the Digia 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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** $QT_END_LICENSE$
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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);
    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 * 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;
    }
}
