/****************************************************************************

This file is part of the wolfenqt project on http://qt.gitorious.org.

Copyright (c) 2009 Nokia Corporation and/or its subsidiary(-ies).*
All rights reserved.

Contact:  Nokia Corporation (qt-info@nokia.com)**

You may use this file under the terms of the BSD license as follows:

"Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are met:
* Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
* Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
* Neither the name of Nokia Corporation and its Subsidiary(-ies) nor the
* names of its contributors may be used to endorse or promote products
* derived from this software without specific prior written permission.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
POSSIBILITY OF SUCH DAMAGE."

****************************************************************************/
#include "mazescene.h"

#include <QCheckBox>
#include <QComboBox>
#include <QGraphicsProxyWidget>
#include <QPainter>
#include <QPushButton>
#include <QKeyEvent>
#include <QTimer>
#include <QVBoxLayout>
#if 0
#include <QWebView>
#endif
#include <QGraphicsWebView>

#include <qmath.h>
#include <qdebug.h>

#include <limits>

#include "scriptwidget.h"
#include "entity.h"
#include "modelitem.h"

#include <QVector3D>

#ifdef USE_PHONON
#include "mediaplayer/mediaplayer.h"
#endif

#ifndef QT_NO_OPENGL
#include <QGLWidget>
#endif

View::View()
    : m_scene(0)
    , m_firstPaint(true)
{
}

void View::setScene(MazeScene *scene)
{
    QGraphicsView::setScene(scene);

    m_scene = scene;
    m_scene->viewResized(this);
}

void View::resizeEvent(QResizeEvent *)
{
    resetMatrix();
    qreal factor = width() / 4.0;
    scale(factor, factor);

    if (m_scene)
        m_scene->viewResized(this);
}

void View::paintEvent(QPaintEvent *event)
{
    if (m_firstPaint) {
        QPainter p(viewport());
	static_cast<MazeScene *>(scene())->setAcceleratedViewport(
            p.paintEngine()->type() == QPaintEngine::OpenGL
            || p.paintEngine()->type() == QPaintEngine::OpenGL2);
        m_firstPaint = false;
    }

    QGraphicsView::paintEvent(event);
}

Light::Light(const QPointF &pos, qreal intensity)
    : m_pos(pos)
    , m_intensity(intensity)
{
}

qreal Light::intensityAt(const QPointF &pos) const
{
    const qreal quadraticIntensity = 150 * m_intensity;
    const qreal linearIntensity = 30 * m_intensity;

    const qreal d = QLineF(m_pos, pos).length();
    return quadraticIntensity / (d * d)
        + linearIntensity / d;
}

QMatrix4x4 fromRotation(float angle, Qt::Axis axis)
{
    QMatrix4x4 m;
    if (axis == Qt::XAxis)
        m.rotate(angle, QVector3D(1, 0, 0));
    else if (axis == Qt::YAxis)
        m.rotate(-angle, QVector3D(0, 1, 0));
    else if (axis == Qt::ZAxis)
        m.rotate(angle, QVector3D(0, 0, 1));
    return m;
}

QMatrix4x4 fromProjection(float fovAngle)
{
    float fov = qCos(fovAngle / 2) / qSin(fovAngle / 2);

    float zNear = 0.01;
    float zFar = 1000;

    float m33 = (zNear + zFar) / (zNear - zFar);
    float m34 = (2 * zNear * zFar) / (zNear - zFar);

    qreal data[] =
    {
        fov, 0, 0, 0,
        0, fov, 0, 0,
        0, 0, m33, m34,
        0, 0, -1, 0
    };
    return QMatrix4x4(data);
}

class WalkingItem : public QGraphicsPixmapItem
{
public:
    WalkingItem(MazeScene *scene);

    void mousePressEvent(QGraphicsSceneMouseEvent *event);

    bool walking() const { return m_walking; }

private:
    void updatePixmap();

    MazeScene *m_scene;
    bool m_walking;

    QPixmap m_walkingPixmap;
    QPixmap m_standingPixmap;
};

QPixmap colorize(const QPixmap &source, const QColor &color)
{
    QImage temp(source.size(), QImage::Format_ARGB32_Premultiplied);

    temp.fill(0x0);
    QPainter p(&temp);
    p.drawPixmap(0, 0, source);
    p.setCompositionMode(QPainter::CompositionMode_SourceIn);
    p.fillRect(temp.rect(), color);
    p.end();

    return QPixmap::fromImage(temp);
}

WalkingItem::WalkingItem(MazeScene *scene)
    : m_scene(scene)
    , m_walking(false)
    , m_walkingPixmap(colorize(QPixmap("walking.png"), QColor(Qt::green).darker()))
    , m_standingPixmap(colorize(QPixmap("standing.png"), QColor(Qt::green).darker()))
{
    setShapeMode(BoundingRectShape);
    updatePixmap();
}

void WalkingItem::mousePressEvent(QGraphicsSceneMouseEvent *event)
{
    event->accept();
    m_walking = !m_walking;
    updatePixmap();
}

void WalkingItem::updatePixmap()
{
    if (m_walking)
        setPixmap(m_walkingPixmap);
    else
        setPixmap(m_standingPixmap);
}

MazeScene::MazeScene(const QVector<Light> &lights, const char *map, int width, int height)
    : m_lights(lights)
    , m_walkingVelocity(0)
    , m_strafingVelocity(0)
    , m_turningSpeed(0)
    , m_pitchSpeed(0)
    , m_deltaYaw(0)
    , m_deltaPitch(0)
    , m_simulationTime(0)
    , m_walkTime(0)
    , m_width(width)
    , m_height(height)
    , m_player(0)
    , m_accelerated(false)
{
    m_camera.setPos(QPointF(1.5, 1.5));
    m_camera.setYaw(0.1);

    m_doorAnimation = new QTimeLine(1000, this);
    m_doorAnimation->setUpdateInterval(20);
    connect(m_doorAnimation, SIGNAL(valueChanged(qreal)), this, SLOT(moveDoors(qreal)));

    QMap<char, int> types;
    types[' '] = -2;
    types['-'] = -1;
    types['#'] = 0;
    types['&'] = 1;
    types['@'] = 2;
    types['%'] = 3;
    types['$'] = 4;
    types['?'] = 5;
    types['!'] = 6;
    types['='] = 7;
    types['*'] = 8;
    types['/'] = 9;
    types['.'] = 10;

    int type;
    for (int y = 0; y < height; ++y) {
        for (int x = 0; x < width; ++x) {
            type = types[map[y*width+x]];
            if (type >= 0)
                continue;

            type = types[map[(y-1)*width+x]];
            if (type >= -1)
                addWall(QPointF(x, y), QPointF(x+1, y), type);

            type = types[map[(y+1)*width+x]];
            if (type >= -1)
                addWall(QPointF(x+1, y+1), QPointF(x, y+1), type);

            type = types[map[y*width+x-1]];
            if (type >= -1)
                addWall(QPointF(x, y+1), QPointF(x, y), type);

            type = types[map[y*width+x+1]];
            if (type >= -1)
                addWall(QPointF(x+1, y), QPointF(x+1, y+1), type);
        }
    }

    QTimer *timer = new QTimer(this);
    timer->setInterval(20);
    timer->start();
    connect(timer, SIGNAL(timeout()), this, SLOT(move()));

    m_time.start();
    updateTransforms();
    updateRenderer();

    m_walkingItem = new WalkingItem(this);
    m_walkingItem->scale(0.008, 0.008);
    m_walkingItem->setZValue(100000);

    addItem(m_walkingItem);
}

void MazeScene::setAcceleratedViewport(bool accelerated)
{
    m_accelerated = accelerated;

    if (!accelerated)
        QTimer::singleShot(0, this, SLOT(toggleRenderer()));

    updateRenderer();
}

void MazeScene::viewResized(QGraphicsView *view)
{
    QRectF bounds = m_walkingItem->sceneBoundingRect();
    QPointF bottomLeft = view->mapToScene(QPoint(5, view->height() - 5));

    m_walkingItem->setPos(bottomLeft.x(), bottomLeft.y() - bounds.height());
}

void MazeScene::addProjectedItem(ProjectedItem *item)
{
    addItem(item);
    m_projectedItems << item;
}

void MazeScene::addWall(const QPointF &a, const QPointF &b, int type)
{
    WallItem *item = new WallItem(this, a, b, type);
#ifdef USE_PHONON
    if (item->childItem() && item->type() == 7) {
        m_playerPos = (a + b ) / 2;
        m_player = static_cast<MediaPlayer *>(item->childItem()->widget());
    }
#endif

#if 0
    QGraphicsProxyWidget *proxy = item->childItem();
    QWebView *view = proxy ? qobject_cast<QWebView *>(proxy->widget()) : 0;
    if (view) {
        connect(view, SIGNAL(loadFinished(bool)), this, SLOT(loadFinished()));
        proxy->setVisible(false);
    }
#endif
    item->setVisible(false);
    addProjectedItem(item);
    m_walls << item;

    if (type == -1)
        m_doors << item;

    setSceneRect(-1, -1, 2, 2);
    if (item->childItem()) {
        QObject *widget = item->childItem()->widget()->children().value(0);
        QPushButton *button = qobject_cast<QPushButton *>(widget);
        if (button)
            m_buttons << button;
    }
}

void MazeScene::loadFinished()
{
    QWidget *widget = qobject_cast<QWidget *>(sender());

    if (widget) {
        foreach (WallItem *item, m_walls) {
            QGraphicsProxyWidget *proxy = item->childItem();
            if (proxy && proxy->widget() == widget)
                proxy->setVisible(true);
        }
    }
}

static inline QTransform rotatingTransform(qreal angle)
{
    QTransform transform;
    transform.rotate(angle);
    return transform;
}

void Camera::setPitch(qreal pitch)
{
    m_pitch = qBound(qreal(-30), pitch, qreal(30));
    m_matrixDirty = true;
}

void Camera::setYaw(qreal yaw)
{
    m_yaw = yaw;
    m_matrixDirty = true;
}

void Camera::setPos(const QPointF &pos)
{
    m_pos = pos;
    m_matrixDirty = true;
}

void Camera::setFov(qreal fov)
{
    m_fov = fov;
    m_matrixDirty = true;
}

void Camera::setTime(qreal time)
{
    m_time = time;
    m_matrixDirty = true;
}


const QMatrix4x4 &Camera::viewMatrix() const
{
    updateMatrix();
    return m_viewMatrix;
}

const QMatrix4x4 &Camera::viewProjectionMatrix() const
{
    updateMatrix();
    return m_viewProjectionMatrix;
}

void Camera::updateMatrix() const
{
    if (!m_matrixDirty)
        return;

    m_matrixDirty = false;

    QMatrix4x4 m;
    m.scale(-1, 1, 1);
    m *= fromRotation(m_yaw + 180, Qt::YAxis);
    m.translate(-m_pos.x(), 0.04 * qSin(10 * m_time) + 0.1, -m_pos.y());
    m = fromRotation(m_pitch, Qt::XAxis) * m;
    m_viewMatrix = m;
    m_viewProjectionMatrix = fromProjection(m_fov) * m_viewMatrix;
}

void MazeScene::drawBackground(QPainter *painter, const QRectF &)
{
    static QImage floor = QImage("floor.png").convertToFormat(QImage::Format_RGB32);
    QBrush floorBrush(floor);

    static QImage ceiling = QImage("ceiling.png").convertToFormat(QImage::Format_RGB32);
    QBrush ceilingBrush(ceiling);

    QTransform brushScale;
    brushScale.scale(0.5 / floor.width(), 0.5 / floor.height());
    floorBrush.setTransform(brushScale);
    ceilingBrush.setTransform(brushScale);

    const QRectF r(1, 1, m_width-2, m_height-2);

    QMatrix4x4 m = m_camera.viewProjectionMatrix();

    QMatrix4x4 floorMatrix = m;
    floorMatrix.translate(0, 0.5, 0);
    floorMatrix *= fromRotation(90, Qt::XAxis);

    painter->save();
    painter->setTransform(floorMatrix.toTransform(0), true);
    painter->fillRect(r, floorBrush);
    painter->restore();

    QMatrix4x4 ceilingMatrix = m;
    ceilingMatrix.translate(0, -0.5, 0);
    ceilingMatrix *= fromRotation(90, Qt::XAxis);

    painter->save();
    painter->setTransform(ceilingMatrix.toTransform(0), true);
    painter->fillRect(r, ceilingBrush);
    painter->restore();
}

void MazeScene::addEntity(Entity *entity)
{
    addProjectedItem(entity);
    m_entities << entity;
}

ProjectedItem::ProjectedItem(const QRectF &bounds, bool shadow, bool opaque)
    : m_bounds(bounds)
    , m_shadowItem(0)
    , m_opaque(opaque)
    , m_obscured(false)
{
    if (shadow) {
        m_shadowItem = new QGraphicsRectItem(bounds, this);
        m_shadowItem->setPen(Qt::NoPen);
        m_shadowItem->setZValue(10);
    }

    m_targetRect = m_bounds;
}

void ProjectedItem::setOpaque(bool opaque)
{
    m_opaque = opaque;
}

bool ProjectedItem::isOpaque() const
{
    return m_opaque;
}

void ProjectedItem::setPosition(const QPointF &a, const QPointF &b)
{
    m_a = a;
    m_b = b;
}

void ProjectedItem::setLightingEnabled(bool enable)
{
    if (m_shadowItem)
        m_shadowItem->setVisible(enable);
}

class ProxyWidget : public QGraphicsProxyWidget
{
public:
    ProxyWidget(QGraphicsItem *parent = 0)
        : QGraphicsProxyWidget(parent)
    {
    }

protected:
    QVariant itemChange(GraphicsItemChange change, const QVariant & value)
    {
        // we want the position of proxy widgets to stay at (0, 0)
        // so ignore the position changes from the native QWidget
        if (change == ItemPositionChange)
            return QPointF();
        else
            return QGraphicsProxyWidget::itemChange(change, value);
    }
};


WallItem::WallItem(MazeScene *scene, const QPointF &a, const QPointF &b, int type)
    : ProjectedItem(QRectF(-0.5, -0.5, 1.0, 1.0))
    , m_type(type)
{
    setPosition(a, b);

    static QImage brown = QImage("brown.png").convertToFormat(QImage::Format_RGB32);
    static QImage book = QImage("book.png").convertToFormat(QImage::Format_RGB32);
    static QImage door = QImage("door.png").convertToFormat(QImage::Format_RGB32);

    switch (type) {
    case -1:
        setImage(door);
        break;
    case 1:
        setImage(book);
        break;
    case 2:
        setOpaque(false);
        break;
    default:
        setImage(brown);
        break;
    }

    m_scale = 0.8;

    m_childItem = 0;
    QWidget *childWidget = 0;
    if (type == 3 && a.y() == b.y()) {
        QWidget *widget = new QWidget;
        QPushButton *button = new QPushButton("Open Sesame", widget);
        QObject::connect(button, SIGNAL(clicked()), scene, SLOT(toggleDoors()));
        widget->setLayout(new QVBoxLayout);
        widget->layout()->addWidget(button);
        childWidget = widget;
        m_scale = 0.3;
    } else if (type == 4) {
        View *view = new View;
        view->setViewportUpdateMode(QGraphicsView::FullViewportUpdate);
        view->resize(480, 320); // not soo big
        view->setViewport(new QWidget); // no OpenGL here
        childWidget = view;
    } else if (type == 5) {
        Entity *entity = new Entity(QPointF(6.5, 2.5));
        scene->addEntity(entity);
        childWidget = new ScriptWidget(scene, entity);
    } else if (type == 7) {
#ifdef USE_PHONON
        Q_INIT_RESOURCE(mediaplayer);
        childWidget = new MediaPlayer(QString());
        m_scale = 0.6;
#endif
    } else if (type == 8) {
        ModelItem *dialog = new ModelItem;
        childWidget = dialog;
        scene->addProjectedItem(dialog);
        m_scale = 0.5;
    } else if (type == 9) {
        if (a.x() > b.x()) {
#if 0
            QWebView *view = new QWebView;
            view->setUrl(QUrl(QLatin1String("http://www.google.com")));
            childWidget = view;
#endif
            QGraphicsWebView *view = new QGraphicsWebView(this);
            view->setCacheMode(QGraphicsItem::ItemCoordinateCache);
            view->setResizesToContents(false);
            view->setGeometry(QRectF(0, 0, 800, 600));
            view->setUrl(QUrl(QLatin1String("http://www.google.com")));

            QRectF rect = view->boundingRect();
            QPointF center = rect.center();
            qreal scale = qMin(m_scale / rect.width(), m_scale / rect.height());
            view->translate(0, -0.05);
            view->scale(scale, scale);
            view->translate(-center.x(), -center.y());
        }
    } else if (type == 10) {
#ifndef QT_NO_OPENGL
        QWidget *widget = new QWidget;
        QCheckBox *checkBox = new QCheckBox("Use OpenGL", widget);
        checkBox->setChecked(true);
        QObject::connect(checkBox, SIGNAL(toggled(bool)), scene, SLOT(toggleRenderer()), Qt::QueuedConnection);
        widget->setLayout(new QVBoxLayout);
        widget->layout()->addWidget(checkBox);
        childWidget = widget;
        m_scale = 0.2;
#endif
    }

    if (!childWidget)
        return;

    childWidget->installEventFilter(scene);

    m_childItem = new ProxyWidget(this);
    m_childItem->setWidget(childWidget);
    m_childItem->setCacheMode(QGraphicsItem::ItemCoordinateCache);

    QRectF rect = m_childItem->boundingRect();
    QPointF center = rect.center();

    qreal scale = qMin(m_scale / rect.width(), m_scale / rect.height());
    m_childItem->translate(0, -0.05);
    m_childItem->scale(scale, scale);
    m_childItem->translate(-center.x(), -center.y());
}

bool MazeScene::eventFilter(QObject *target, QEvent *event)
{
    QWidget *widget = qobject_cast<QWidget *>(target);
    if (!widget || event->type() != QEvent::Resize)
        return false;

    foreach (WallItem *item, m_walls) {
        QGraphicsProxyWidget *proxy = item->childItem();
        if (proxy && proxy->widget() == widget)
            item->childResized();
    }

    return false;
}

void WallItem::childResized()
{
    QRectF rect = m_childItem->boundingRect();

    QPointF center = rect.center();

    qreal scale = qMin(m_scale / rect.width(), m_scale / rect.height());
    m_childItem->resetMatrix();
    m_childItem->translate(0, -0.05);
    m_childItem->scale(scale, scale);
    m_childItem->translate(-center.x(), -center.y());

    // refresh cache size
    m_childItem->setCacheMode(QGraphicsItem::NoCache);
    m_childItem->setCacheMode(QGraphicsItem::ItemCoordinateCache);
}

void ProjectedItem::updateLighting(const QVector<Light> &lights, bool useConstantLight)
{
    if (!m_shadowItem)
        return;

    if (useConstantLight) {
        m_shadowItem->setBrush(QColor(0, 0, 0, 100));
        return;
    }

    const qreal constantIntensity = 80;
    qreal la = constantIntensity;
    qreal lb = constantIntensity;
    foreach (const Light &light, lights) {
        la += light.intensityAt(m_b);
        lb += light.intensityAt(m_a);
    }

    int va = qMax(0, 255 - int(la));
    int vb = qMax(0, 255 - int(lb));

    if (va == vb) {
        m_shadowItem->setBrush(QColor(0, 0, 0, va));
    } else {
        const QRectF rect = boundingRect();
        QLinearGradient g(rect.topLeft(), rect.topRight());

        g.setColorAt(0, QColor(0, 0, 0, va));
        g.setColorAt(1, QColor(0, 0, 0, vb));

        m_shadowItem->setBrush(g);
    }
}

QRectF ProjectedItem::boundingRect() const
{
    return m_bounds;
}

void ProjectedItem::paint(QPainter *painter, const QStyleOptionGraphicsItem *, QWidget *)
{
    if (!m_image.isNull()) {
        QRectF target = m_targetRect.translated(0.5, 0.5);
        QRectF source = QRectF(0, 0, m_image.width() * (1 - target.x()), m_image.height());
        painter->drawImage(m_targetRect, m_image, source);
    }
}

void ProjectedItem::setAnimationTime(qreal time)
{
    // hacky way of handling door animation
    QRectF rect = boundingRect();
    m_targetRect = QRectF(QPointF(rect.left() + rect.width() * time, rect.top()),
                          rect.bottomRight());
    if (m_shadowItem)
        m_shadowItem->setRect(m_targetRect);
    update();
}

void ProjectedItem::setImage(const QImage &image)
{
    m_image = image;
    update();
}

void ProjectedItem::setObscured(bool obscured)
{
    m_obscured = obscured;
}

bool ProjectedItem::isObscured() const
{
    return m_obscured;
}

void ProjectedItem::updateTransform(const Camera &camera)
{
    if (!m_obscured) {
        QTransform rotation;
        rotation *= QTransform().translate(-camera.pos().x(), -camera.pos().y());
        rotation *= rotatingTransform(camera.yaw());
        QPointF center = (m_a + m_b) / 2;

        QPointF ca = rotation.map(m_a);
        QPointF cb = rotation.map(m_b);

        if (ca.y() > 0 || cb.y() > 0) {
            QMatrix4x4 m = camera.viewProjectionMatrix();
            m.translate(center.x(), 0, center.y());
            m *= fromRotation(-QLineF(m_b, m_a).angle(), Qt::YAxis);

            qreal zm = QLineF(camera.pos(), center).length();

            setVisible(true);
            setZValue(-zm);
            setTransform(m.toTransform(0));
            return;
        }
    }

    // hide the item by placing it far outside the scene
    // we could use setVisible() but that causes unnecessary
    // update to cahced items
    QTransform transform;
    transform.translate(-1000, -1000);
    setTransform(transform);
}


void MazeScene::mouseMoveEvent(QGraphicsSceneMouseEvent *event)
{
    if (focusItem()) {
        QGraphicsScene::mouseMoveEvent(event);
        return;
    }

    if (event->buttons() & Qt::LeftButton) {
        QPointF delta(event->scenePos() - event->lastScenePos());
        m_deltaYaw += delta.x() * 80;
        m_deltaPitch -= delta.y() * 80;
    }
}

void MazeScene::keyPressEvent(QKeyEvent *event)
{
    if (handleKey(event->key(), true)) {
        event->accept();
        return;
    }

    QGraphicsScene::keyPressEvent(event);
}

void MazeScene::keyReleaseEvent(QKeyEvent *event)
{
    if (handleKey(event->key(), false)) {
        event->accept();
        return;
    }

    QGraphicsScene::keyReleaseEvent(event);
}

bool MazeScene::handleKey(int key, bool pressed)
{
    if (focusItem())
        return false;

    switch (key) {
    case Qt::Key_Left:
    case Qt::Key_Q:
        m_turningSpeed = (pressed ? -0.5 : 0.0);
        return true;
    case Qt::Key_Right:
    case Qt::Key_E:
        m_turningSpeed = (pressed ? 0.5 : 0.0);
        return true;
    case Qt::Key_Down:
        m_pitchSpeed = (pressed ? 0.5 : 0.0);
        return true;
    case Qt::Key_Up:
        m_pitchSpeed = (pressed ? -0.5 : 0.0);
        return true;
    case Qt::Key_S:
        m_walkingVelocity = (pressed ? -0.01 : 0.0);
        return true;
    case Qt::Key_W:
        m_walkingVelocity = (pressed ? 0.01 : 0.0);
        return true;
    case Qt::Key_A:
        m_strafingVelocity = (pressed ? -0.01 : 0.0);
        return true;
    case Qt::Key_D:
        m_strafingVelocity = (pressed ? 0.01 : 0.0);
        return true;
    }

    return false;
}

static inline QRectF rectFromPoint(const QPointF &point, qreal size)
{
    return QRectF(point, point).adjusted(-size/2, -size/2, size/2, size/2);
}

bool MazeScene::blocked(const QPointF &pos, Entity *me) const
{
    const QRectF rect = rectFromPoint(pos, me ? 0.7 : 0.25);

    foreach (WallItem *item, m_walls) {
        if (item->type() == 6
            || (item->type() == -1 && m_doorAnimation->state() != QTimeLine::Running
               && m_doorAnimation->direction() == QTimeLine::Backward))
            continue;

        const QPointF a = item->a();
        const QPointF b = item->b();

        QRectF wallRect = QRectF(a, b).adjusted(-0.01, -0.01, 0.01, 0.01);

        if (wallRect.intersects(rect))
            return true;
    }

    foreach (Entity *entity, m_entities) {
        if (entity == me)
            continue;
        QRectF entityRect = rectFromPoint(entity->pos(), 0.8);

        if (entityRect.intersects(rect))
            return true;
    }

    if (me) {
        QRectF cameraRect = rectFromPoint(m_camera.pos(), 0.4);

        if (cameraRect.intersects(rect))
            return true;
    }

    return false;
}

bool MazeScene::tryMove(QPointF &pos, const QPointF &delta, Entity *entity) const
{
    const QPointF old = pos;

    if (delta.x() != 0 && !blocked(pos + QPointF(delta.x(), 0), entity))
        pos.setX(pos.x() + delta.x());

    if (delta.y() != 0 && !blocked(pos + QPointF(0, delta.y()), entity))
        pos.setY(pos.y() + delta.y());

    return pos != old;
}

struct Span
{
    ProjectedItem *item;

    // screen coordinates
    float sx1;
    float sx2;

    float cy;
};

int split(QList<Span> &list, float x)
{
    for (int i = 0; i < list.size(); ++i) {
        Span &span = list[i];
        if (span.sx2 == x)
            return i+1;

        if (span.sx1 <= x && span.sx2 > x) {
            Span split = span;
            span.sx2 = x;
            split.sx1 = x;
            list.insert(i+1, split);
            return i+1;
        }
    }
    return -1;
}

bool insertSpan(QList<Span> &list, const Span &span, bool checkOnly)
{
    int left = split(list, span.sx1);
    int right = split(list, span.sx2);

    bool visible = false;
    for (int i = left; i < right; ++i) {
        Span &s = list[i];
        if (s.cy > span.cy) {
            visible = true;
            if (!checkOnly) {
                s.item = span.item;
                s.cy = span.cy;
            }
        }
    }
    return visible;
}

bool insertProjectedItem(QList<Span> &list, ProjectedItem *item, const QTransform &cameraTransform, bool checkOnly)
{
    QPointF ca = cameraTransform.map(item->a());
    QPointF cb = cameraTransform.map(item->b());

    if (ca.y() <= 0 && cb.y() <= 0)
        return false;

    const float clip = 0.0001;
    if (ca.y() <= 0) {
        float t = (clip - ca.y()) / (cb.y() - ca.y());
        ca.setX(ca.x() + t * (cb.x() - ca.x()));
        ca.setY(clip);
    } else if(cb.y() <= 0) {
        float t = (clip - ca.y()) / (cb.y() - ca.y());
        cb.setX(ca.x() + t * (cb.x() - ca.x()));
        cb.setY(clip);
    }

    Span span;
    span.item = item;
    span.sx1 = ca.x() / ca.y();
    span.sx2 = cb.x() / cb.y();
    span.cy = (ca.y() + cb.y()) * 0.5f;

    if (span.sx1 >= span.sx2)
        qSwap(span.sx1, span.sx2);

    return insertSpan(list, span, checkOnly);
}

void MazeScene::updateTransforms()
{
    Span span;
    span.item = 0;
    span.sx1 = -std::numeric_limits<float>::infinity();
    span.sx2 =  std::numeric_limits<float>::infinity();
    span.cy = std::numeric_limits<float>::infinity();

    QList<Span> visibleList;
    visibleList << span;

    QTransform rotation;
    rotation *= QTransform().translate(-m_camera.pos().x(), -m_camera.pos().y());
    rotation *= rotatingTransform(m_camera.yaw());

    // first add all opaque items
    foreach (ProjectedItem *item, m_projectedItems) {
        if (item->isOpaque()) {
            item->setObscured(true);
            insertProjectedItem(visibleList, item, rotation, false);
        }
    }

    // mark visible opaque items
    for (int i = 0; i < visibleList.size(); ++i)
        if (visibleList.at(i).item)
            visibleList.at(i).item->setObscured(false);

    // now add all non-opaque items
    foreach (ProjectedItem *item, m_projectedItems) {
        if (!item->isOpaque())
            item->setObscured(!insertProjectedItem(visibleList, item, rotation, true));
    }

    foreach (ProjectedItem *item, m_projectedItems)
        item->updateTransform(m_camera);

    foreach (WallItem *item, m_walls) {
        if (item->isVisible() && !item->isObscured()) {
            // embed recursive scene
            if (QGraphicsProxyWidget *child = item->childItem()) {
                View *view = qobject_cast<View *>(child->widget());
                if (view && !view->scene()) {
                    const char *map =
                        "#$###"
                        "#   #"
                        "# @ #"
                        "#   #"
                        "#####";
                    QVector<Light> lights;
                    lights << Light(QPointF(2.5, 2.5), 1)
                           << Light(QPointF(1.5, 1.5), 0.4);
                    MazeScene *embeddedScene = new MazeScene(lights, map, 5, 5);
                    view->setScene(embeddedScene);
                    view->setRenderHints(QPainter::SmoothPixmapTransform | QPainter::Antialiasing);
                }
            }
        }
    }

#ifdef USE_PHONON
    if (m_player) {
        qreal distance = QLineF(m_camera.pos(), m_playerPos).length();
        m_player->setVolume(qPow(2, -0.3 * distance));
    }
#endif
    setFocusItem(0); // setVisible(true) might give focus to one of the items
    update();
}

void MazeScene::move()
{
    QSet<Entity *> movedEntities;
    long elapsed = m_time.elapsed();
    bool walked = false;

    const int stepSize = 5;
    int steps = (elapsed - m_simulationTime) / stepSize;

    if (steps) {
        m_deltaYaw /= steps;
        m_deltaPitch /= steps;

        m_deltaYaw += m_turningSpeed;
        m_deltaPitch += m_pitchSpeed;
    }

    qreal walkingVelocity = m_walkingVelocity;
    if (m_walkingItem->walking())
        walkingVelocity = 0.005;

    for (int i = 0; i < steps; ++i) {
        m_camera.setYaw(m_camera.yaw() + m_deltaYaw);
        m_camera.setPitch(m_camera.pitch() + m_deltaPitch);

        bool walking = false;
        if (walkingVelocity != 0) {
            QPointF walkingDelta = QLineF::fromPolar(walkingVelocity, m_camera.yaw() - 90).p2();
            QPointF pos = m_camera.pos();
            if (tryMove(pos, walkingDelta)) {
                walking = true;
                m_camera.setPos(pos);
            }
        }

        if (m_strafingVelocity != 0) {
            QPointF walkingDelta = QLineF::fromPolar(m_strafingVelocity, m_camera.yaw()).p2();
            QPointF pos = m_camera.pos();
            if (tryMove(pos, walkingDelta)) {
                walking = true;
                m_camera.setPos(pos);
            }
        }

        walked = walked || walking;

        if (walking)
            m_walkTime += stepSize;
        m_simulationTime += stepSize;

        foreach (Entity *entity, m_entities) {
            if (entity->move(this))
                movedEntities.insert(entity);
        }
    }

    m_camera.setTime(m_walkTime * 0.001);

    if (walked || m_deltaYaw != 0 || m_deltaPitch != 0) {
        updateTransforms();
    } else {
        foreach (Entity *entity, movedEntities)
            entity->updateTransform(m_camera);
    }

    if (steps) {
        m_deltaYaw = 0;
        m_deltaPitch = 0;
    }
}

void MazeScene::toggleDoors()
{
    setFocusItem(0);

    if (m_doorAnimation->state() == QTimeLine::Running)
        return;

    foreach (QPushButton *button, m_buttons) {
        if (m_doorAnimation->direction() == QTimeLine::Forward)
            button->setText("Close Sesame!");
        else
            button->setText("Open Sesame!");
    }

    m_doorAnimation->toggleDirection();
    m_doorAnimation->start();
}

void MazeScene::moveDoors(qreal value)
{
    bool opaqueStatusChanged = false;
    foreach (WallItem *item, m_doors) {
        item->setAnimationTime(1 - value);

        bool shouldBeOpaque = qFuzzyCompare(value, 1);
        if (item->isOpaque() != shouldBeOpaque) {
            opaqueStatusChanged = true;
            item->setOpaque(shouldBeOpaque);
        }
    }
    if (opaqueStatusChanged)
        updateTransforms();
}

void MazeScene::toggleRenderer()
{
#ifndef QT_NO_OPENGL
    if (views().size() == 0)
        return;
    QGraphicsView *view = views().at(0);
    if (view) {
        view->setViewport(
                view->viewport()->inherits("QGLWidget")
                ? new QWidget
                : new QGLWidget(QGLFormat(QGL::SampleBuffers)));

        updateRenderer();
    }
#endif
}

void MazeScene::updateRenderer()
{
    QGraphicsView *view = views().isEmpty() ? 0 : views().at(0);
    bool accelerated = m_accelerated || view && view->viewport()->inherits("QGLWidget");
    if (view) {
        if (accelerated)
            view->setRenderHints(QPainter::Antialiasing | QPainter::SmoothPixmapTransform);
        else
            view->setRenderHints(QPainter::Antialiasing);
    }

    foreach (WallItem *item, m_walls)
        item->updateLighting(m_lights, item->type() == 2);
}