#include <cassert>
#include <cmath>
#include <iostream>
#include <boost/shared_ptr.hpp>
#include <boost/static_assert.hpp>
#include <boost/timer.hpp>
#include <QApplication>
#include <QBitmap>
#include <QDialog>
#include <QGraphicsPixmapItem>
#include <QGraphicsScene>
#include <QGraphicsView>
#include <QTimer>
#include <QVBoxLayout>
BOOST_STATIC_ASSERT(sizeof(qreal)==sizeof(double)
&& "Assume use of double is equivalent of qreal");
struct Background : public QGraphicsPixmapItem
{
Background(const int width = 256, const int height = 256)
{
QImage i(width,height,QImage::Format_ARGB32);
for (int y=0;y!=height;++y)
{
for (int x=0;x!=width;++x)
{
const int gray = (x + y) % 256;
i.setPixel(QPoint(x,y),QColor(gray,gray,gray).rgb());
}
}
this->setPixmap(this->pixmap().fromImage(i));
}
};
struct Sprite : public QGraphicsPixmapItem
{
Sprite(const int width = 32, const int height = 32)
: dx(1.0), dy(1.0), maxx(0.0), maxy(0.0)
{
QImage i(width,height,QImage::Format_ARGB32);
for (int y=0;y!=height;++y)
{
for (int x=0;x!=width;++x)
{
const int gray = ((8 * x) + (8 * y)) % 256;
i.setPixel(QPoint(x,y),QColor(gray,gray,gray).rgb());
}
}
this->setPixmap(this->pixmap().fromImage(i));
}
void advance(int)
{
double new_x = this->x();
double new_y = this->y();
new_x+=dx;
new_y+=dy;
if (new_x<0.0 || new_x>maxx) dx= -dx;
if (new_y<0.0 || new_y>maxy) dy= -dy;
this->setX(new_x);
this->setY(new_y);
}
void setRect(const int width, const int height)
{
maxx = static_cast<double>(width - this->pixmap().width() );
maxy = static_cast<double>(height - this->pixmap().height());
}
private:
double dx;
double dy;
double maxx;
double maxy;
};
int main(int argc, char *argv[])
{
QApplication a(argc, argv);
//Start with creating a scene
boost::shared_ptr<QGraphicsScene> scene(new QGraphicsScene);
//Add background to scene
boost::shared_ptr<Background> background(new Background);
scene->addItem(background.get());
//Add sprites to scene
std::vector<boost::shared_ptr<Sprite> > sprites;
//Add multiple sprites
{
const int n_sprites = 20;
const double midx = background->pixmap().width() / 2.0;
const double midy = background->pixmap().height() / 2.0;
const double ray = std::min(midx,midy) * 0.8;
const double d_angle = 2.0 * M_PI / static_cast<double>(n_sprites);
double angle = 0.0;
for (int i=0; i!=n_sprites; ++i)
{
boost::shared_ptr<Sprite> sprite(new Sprite);
const double x = midx + (std::sin(angle) * ray) - (sprite->pixmap().width() / 2);
const double y = midy - (std::cos(angle) * ray) - (sprite->pixmap().height() / 2);
sprite->setX(x);
sprite->setY(y);
sprite->setRect(background->pixmap().width(),background->pixmap().height());
scene->addItem(sprite.get());
sprites.push_back(sprite);
angle+=d_angle;
}
}
//Connect a view to display the scene
boost::shared_ptr<QGraphicsView> view(new QGraphicsView);
view->setScene(scene.get());
//Create a layout to put the scene in
boost::shared_ptr<QVBoxLayout> layout(new QVBoxLayout);
layout->addWidget(view.get());
//Create a dialog to display to laid-out-scene
boost::shared_ptr<QDialog> dialog(new QDialog);
dialog->setLayout(layout.get());
dialog->setGeometry(view->rect());
//Create a timer to call 'advance' on all sprites'
boost::shared_ptr<QTimer> timer(new QTimer(scene.get()));
timer->connect(timer.get(), SIGNAL(timeout()), scene.get(), SLOT(advance()));
timer->start(20);
//Show the graphicsscene with its sprites
dialog->show();
return a.exec();
}
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