qt5base-lts/examples/widgets/effects/lighting/lighting.cpp
Allan Sandfeld Jensen 515e802ae2 Use C++ <cmath> instead of <math.h>
Including math.h can pollute the default namespace, and break
some compilers if cmath versions of the method are declared as using.

Switching to C++ math functions also greatly simplifies handling of
float qreal as C++ automatically chooses the right method.

[ChangeLog][QtCore][QtMath] qmath.h no longer includes math.h, so any
sources depending on that indirect inclusion may fail to build.

Change-Id: I4d0e331dafba354ec05dc5052e61ef4ff8d387fe
Reviewed-by: Rafael Roquetto <rafael.roquetto@kdab.com>
2015-02-16 16:21:15 +00:00

141 lines
4.6 KiB
C++

/****************************************************************************
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#include "lighting.h"
#include <QtWidgets>
#include <QtCore/qmath.h>
#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 * qSin(angle) - 40 + 25;
qreal ys = 200 * qCos(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 = qSqrt(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 */)
{
}