qt5base-lts/examples/opengl/overpainting/bubble.cpp

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/****************************************************************************
**
** Copyright (C) 2013 Digia Plc and/or its subsidiary(-ies).
** Contact: http://www.qt-project.org/legal
**
** This file is part of the examples of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:BSD$
** 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 Digia Plc 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.
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**
** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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****************************************************************************/
#include "bubble.h"
Bubble::Bubble(const QPointF &position, qreal radius, const QPointF &velocity)
: position(position), vel(velocity), radius(radius)
{
innerColor = randomColor();
outerColor = randomColor();
updateBrush();
}
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);
}
void Bubble::drawBubble(QPainter *painter)
{
painter->save();
painter->translate(position.x() - radius, position.y() - radius);
painter->setBrush(brush);
painter->drawEllipse(0, 0, int(2*radius), int(2*radius));
painter->restore();
}
QColor Bubble::randomColor()
{
int red = int(205 + 50.0*qrand()/(RAND_MAX+1.0));
int green = int(205 + 50.0*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);
}