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

#include <QtGui>

#include <QtOpenGL>

#include <stdlib.h>

#include <math.h>

#include "bubble.h"

#include "qtlogo.h"

#include "glwidget.h"

#ifndef GL_MULTISAMPLE

#define GL_MULTISAMPLE  0x809D

#endif

//! [0]

GLWidget::GLWidget(QWidget *parent)

    : QGLWidget(QGLFormat(QGL::SampleBuffers), parent)

{

    QTime midnight(0, 0, 0);

    qsrand(midnight.secsTo(QTime::currentTime()));

    logo = 0;

    xRot = 0;

    yRot = 0;

    zRot = 0;

    qtGreen = QColor::fromCmykF(0.40, 0.0, 1.0, 0.0);

    qtPurple = QColor::fromCmykF(0.39, 0.39, 0.0, 0.0);

    animationTimer.setSingleShot(false);

    connect(&animationTimer, SIGNAL(timeout()), this, SLOT(animate()));

    animationTimer.start(25);

    setAutoFillBackground(false);

    setMinimumSize(200, 200);

    setWindowTitle(tr("Overpainting a Scene"));

}

//! [0]

//! [1]

GLWidget::~GLWidget()

{

}

//! [1]

static void qNormalizeAngle(int &angle)

{

    while (angle < 0)

        angle += 360 * 16;

    while (angle > 360 * 16)

        angle -= 360 * 16;

}

void GLWidget::setXRotation(int angle)

{

    qNormalizeAngle(angle);

    if (angle != xRot)

        xRot = angle;

}

void GLWidget::setYRotation(int angle)

{

    qNormalizeAngle(angle);

    if (angle != yRot)

        yRot = angle;

}

void GLWidget::setZRotation(int angle)

{

    qNormalizeAngle(angle);

    if (angle != zRot)

        zRot = angle;

}

//! [2]

void GLWidget::initializeGL()

{

    glEnable(GL_MULTISAMPLE);

    logo = new QtLogo(this);

    logo->setColor(qtGreen.dark());

}

//! [2]

void GLWidget::mousePressEvent(QMouseEvent *event)

{

    lastPos = event->pos();

}

void GLWidget::mouseMoveEvent(QMouseEvent *event)

{

    int dx = event->x() - lastPos.x();

    int dy = event->y() - lastPos.y();

    if (event->buttons() & Qt::LeftButton) {

        setXRotation(xRot + 8 * dy);

        setYRotation(yRot + 8 * dx);

    } else if (event->buttons() & Qt::RightButton) {

        setXRotation(xRot + 8 * dy);

        setZRotation(zRot + 8 * dx);

    }

    lastPos = event->pos();

}

void GLWidget::paintEvent(QPaintEvent *event)

{

    makeCurrent();

//! [4]

    glMatrixMode(GL_MODELVIEW);

    glPushMatrix();

//! [4]

//! [6]

    qglClearColor(qtPurple.dark());

    glShadeModel(GL_SMOOTH);

    glEnable(GL_DEPTH_TEST);

    glEnable(GL_CULL_FACE);

    glEnable(GL_LIGHTING);

    glEnable(GL_LIGHT0);

    glEnable(GL_MULTISAMPLE);

    static GLfloat lightPosition[4] = { 0.5, 5.0, 7.0, 1.0 };

    glLightfv(GL_LIGHT0, GL_POSITION, lightPosition);

    setupViewport(width(), height());

//! [6]

//! [7]

    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

    glLoadIdentity();

    glTranslatef(0.0, 0.0, -10.0);

    glRotatef(xRot / 16.0, 1.0, 0.0, 0.0);

    glRotatef(yRot / 16.0, 0.0, 1.0, 0.0);

    glRotatef(zRot / 16.0, 0.0, 0.0, 1.0);

    logo->draw();

//! [7]

//! [8]

    glShadeModel(GL_FLAT);

    glDisable(GL_CULL_FACE);

    glDisable(GL_DEPTH_TEST);

    glDisable(GL_LIGHTING);

    glMatrixMode(GL_MODELVIEW);

    glPopMatrix();

//! [8]

//! [10]

    QPainter painter(this);

    painter.setRenderHint(QPainter::Antialiasing);

    foreach (Bubble *bubble, bubbles) {

        if (bubble->rect().intersects(event->rect()))

            bubble->drawBubble(&painter);

    }

    drawInstructions(&painter);

    painter.end();

}

//! [10]

//! [11]

void GLWidget::resizeGL(int width, int height)

{

    setupViewport(width, height);

}

//! [11]

//! [12]

void GLWidget::showEvent(QShowEvent *event)

{

    Q_UNUSED(event);

    createBubbles(20 - bubbles.count());

}

//! [12]

QSize GLWidget::sizeHint() const

{

    return QSize(400, 400);

}

void GLWidget::createBubbles(int number)

{

    for (int i = 0; i < number; ++i) {

        QPointF position(width()*(0.1 + (0.8*qrand()/(RAND_MAX+1.0))),

                        height()*(0.1 + (0.8*qrand()/(RAND_MAX+1.0))));

        qreal radius = qMin(width(), height())*(0.0125 + 0.0875*qrand()/(RAND_MAX+1.0));

        QPointF velocity(width()*0.0125*(-0.5 + qrand()/(RAND_MAX+1.0)),

                        height()*0.0125*(-0.5 + qrand()/(RAND_MAX+1.0)));

        bubbles.append(new Bubble(position, radius, velocity));

    }

}

//! [13]

void GLWidget::animate()

{

    QMutableListIterator<Bubble*> iter(bubbles);

    while (iter.hasNext()) {

        Bubble *bubble = iter.next();

        bubble->move(rect());

    }

    update();

}

//! [13]

//! [14]

void GLWidget::setupViewport(int width, int height)

{

    int side = qMin(width, height);

    glViewport((width - side) / 2, (height - side) / 2, side, side);

    glMatrixMode(GL_PROJECTION);

    glLoadIdentity();

#ifdef QT_OPENGL_ES

    glOrthof(-0.5, +0.5, -0.5, 0.5, 4.0, 15.0);

#else

    glOrtho(-0.5, +0.5, -0.5, 0.5, 4.0, 15.0);

#endif

    glMatrixMode(GL_MODELVIEW);

}

//! [14]

//! [15]

void GLWidget::drawInstructions(QPainter *painter)

{

    QString text = tr("Click and drag with the left mouse button "

                      "to rotate the Qt logo.");

    QFontMetrics metrics = QFontMetrics(font());

    int border = qMax(4, metrics.leading());

    QRect rect = metrics.boundingRect(0, 0, width() - 2*border, int(height()*0.125),

                                      Qt::AlignCenter | Qt::TextWordWrap, text);

    painter->setRenderHint(QPainter::TextAntialiasing);

    painter->fillRect(QRect(0, 0, width(), rect.height() + 2*border),

                     QColor(0, 0, 0, 127));

    painter->setPen(Qt::white);

    painter->fillRect(QRect(0, 0, width(), rect.height() + 2*border),

                      QColor(0, 0, 0, 127));

    painter->drawText((width() - rect.width())/2, border,

                      rect.width(), rect.height(),

                      Qt::AlignCenter | Qt::TextWordWrap, text);

}

//! [15]