source: trunk/examples/opengl/hellogl_es/bubble.cpp@ 641

/****************************************************************************
**
** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).
** All rights reserved.
** Contact: Nokia Corporation ([email protected])
**
** This file is part of the examples of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL$
** Commercial Usage
** Licensees holding valid Qt Commercial licenses may use this file in
** 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.
**
** If you have questions regarding the use of this file, please contact
** Nokia at [email protected].
** $QT_END_LICENSE$
**
****************************************************************************/

#include <QtGui>

#include "bubble.h"

Bubble::Bubble(const QPointF &position, qreal radius, const QPointF &velocity)
    : position(position), vel(velocity), radius(radius)
{
    innerColor = randomColor();
    outerColor = randomColor();
    cache = 0;
    updateBrush();
}

//! [0]
void Bubble::updateCache()
{
    if (cache)
        delete cache;
    cache = new QImage(qRound(radius * 2 + 2), qRound(radius * 2 + 2), QImage::Format_ARGB32);
    cache->fill(0x00000000);
    QPainter p(cache);
    p.setRenderHint(QPainter::HighQualityAntialiasing);
    QPen pen(Qt::white);
    pen.setWidth(2);
    p.setPen(pen);
    p.setBrush(brush);
    p.drawEllipse(0, 0, int(2*radius), int(2*radius));
}
//! [0]

Bubble::~Bubble()
{
    if (cache)
        delete cache;
}

void Bubble::updateBrush()
{
    QRadialGradient gradient(QPointF(radius, radius), radius,
                             QPointF(radius*0.5, radius*0.5));

    gradient.setColorAt(0, QColor(255, 255, 255, 255));
    gradient.setColorAt(0.25, innerColor);
    gradient.setColorAt(1, outerColor);
    brush = QBrush(gradient);
    updateCache();
}

//! [1]
void Bubble::drawBubble(QPainter *painter)
{
    painter->save();
    painter->translate(position.x() - radius, position.y() - radius);
    painter->setOpacity(0.8);
    painter->drawImage(0, 0, *cache);
    painter->restore();
}
//! [1]

QColor Bubble::randomColor()
{
    int red = int(185 + 70.0*qrand()/(RAND_MAX+1.0));
    int green = int(185 + 70.0*qrand()/(RAND_MAX+1.0));
    int blue = int(205 + 50.0*qrand()/(RAND_MAX+1.0));
    int alpha = int(91 + 100.0*qrand()/(RAND_MAX+1.0));

    return QColor(red, green, blue, alpha);
}

void Bubble::move(const QRect &bbox)
{
    position += vel;
    qreal leftOverflow = position.x() - radius - bbox.left();
    qreal rightOverflow = position.x() + radius - bbox.right();
    qreal topOverflow = position.y() - radius - bbox.top();
    qreal bottomOverflow = position.y() + radius - bbox.bottom();
    
    if (leftOverflow < 0.0) {
        position.setX(position.x() - 2 * leftOverflow);
        vel.setX(-vel.x());
    } else if (rightOverflow > 0.0) {
        position.setX(position.x() - 2 * rightOverflow);
        vel.setX(-vel.x());
    }

    if (topOverflow < 0.0) {
        position.setY(position.y() - 2 * topOverflow);
        vel.setY(-vel.y());
    } else if (bottomOverflow > 0.0) {
        position.setY(position.y() - 2 * bottomOverflow);
        vel.setY(-vel.y());
    }
}

QRectF Bubble::rect()
{
    return QRectF(position.x() - radius, position.y() - radius,
                  2 * radius, 2 * radius);
}