qt5base-lts/examples/effects/lighting/lighting.cpp

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/****************************************************************************
**
** Copyright (C) 2011 Nokia Corporation and/or its subsidiary(-ies).
** All rights reserved.
** Contact: Nokia Corporation (qt-info@nokia.com)
**
** 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 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."
** $QT_END_LICENSE$
**
****************************************************************************/
#include "lighting.h"
#include <QtWidgets>
#ifndef M_PI
#define M_PI 3.14159265358979323846
#endif
Lighting::Lighting(QWidget *parent): QGraphicsView(parent), angle(0.0)
{
setScene(&m_scene);
setupScene();
QTimer *timer = new QTimer(this);
connect(timer, SIGNAL(timeout()), SLOT(animate()));
timer->setInterval(30);
timer->start();
setRenderHint(QPainter::Antialiasing, true);
setFrameStyle(QFrame::NoFrame);
}
void Lighting::setupScene()
{
m_scene.setSceneRect(-300, -200, 600, 460);
QLinearGradient linearGrad(QPointF(-100, -100), QPointF(100, 100));
linearGrad.setColorAt(0, QColor(255, 255, 255));
linearGrad.setColorAt(1, QColor(192, 192, 255));
setBackgroundBrush(linearGrad);
QRadialGradient radialGrad(30, 30, 30);
radialGrad.setColorAt(0, Qt::yellow);
radialGrad.setColorAt(0.2, Qt::yellow);
radialGrad.setColorAt(1, Qt::transparent);
QPixmap pixmap(60, 60);
pixmap.fill(Qt::transparent);
QPainter painter(&pixmap);
painter.setPen(Qt::NoPen);
painter.setBrush(radialGrad);
painter.drawEllipse(0, 0, 60, 60);
painter.end();
m_lightSource = m_scene.addPixmap(pixmap);
m_lightSource->setZValue(2);
for (int i = -2; i < 3; ++i)
for (int j = -2; j < 3; ++j) {
QAbstractGraphicsShapeItem *item;
if ((i + j) & 1)
item = new QGraphicsEllipseItem(0, 0, 50, 50);
else
item = new QGraphicsRectItem(0, 0, 50, 50);
item->setPen(QPen(Qt::black, 1));
item->setBrush(QBrush(Qt::white));
QGraphicsDropShadowEffect *effect = new QGraphicsDropShadowEffect;
effect->setBlurRadius(8);
item->setGraphicsEffect(effect);
item->setZValue(1);
item->setPos(i * 80, j * 80);
m_scene.addItem(item);
m_items << item;
}
}
void Lighting::animate()
{
angle += (M_PI / 30);
qreal xs = 200 * sin(angle) - 40 + 25;
qreal ys = 200 * cos(angle) - 40 + 25;
m_lightSource->setPos(xs, ys);
for (int i = 0; i < m_items.size(); ++i) {
QGraphicsItem *item = m_items.at(i);
Q_ASSERT(item);
QGraphicsDropShadowEffect *effect = static_cast<QGraphicsDropShadowEffect *>(item->graphicsEffect());
Q_ASSERT(effect);
QPointF delta(item->x() - xs, item->y() - ys);
effect->setOffset(delta.toPoint() / 30);
qreal dx = delta.x();
qreal dy = delta.y();
qreal dd = sqrt(dx * dx + dy * dy);
QColor color = effect->color();
color.setAlphaF(qBound(0.4, 1 - dd / 200.0, 0.7));
effect->setColor(color);
}
m_scene.update();
}
void Lighting::resizeEvent(QResizeEvent */*event*/)
{
}