用qt的图形视图框架实现的圆,三角形,矩形运动及碰撞.

/*main.cpp*/
#include "project.h"
#include <QtWidgets/QApplication>

int main(int argc, char *argv[])
{
QApplication a(argc, argv);
Project w;
w.show();
return a.exec();
}

/*project.h*/
#ifndef PROJECT_H
#define PROJECT_H

#include <QtWidgets/QWidget>
#include "ui_project.h"
#include <QGraphicsEllipseItem>
#include <QGraphicsRectItem>
#include <QGraphicsPolygonItem>
#include <QGraphicsScene>
#include <QGraphicsView>
#include <QPolygonF>
class Project : public QWidget
{
Q_OBJECT

public:
Project(QWidget *parent = 0);

protected slots:
void buttonStartClicked();
void buttonPauseClicked();
void buttonStopClicked();
void buttonAddClicked();
void buttonMinusClicked();

protected:
void timerEvent(QTimerEvent *);

private:
Ui::ProjectClass ui;
QGraphicsEllipseItem *ballItem;
QGraphicsRectItem *rectItem;
QGraphicsPolygonItem *triAngleItem;
QGraphicsScene *scene0;
QGraphicsScene *scene1;
QGraphicsScene *scene2;
qreal x0, y0, intervalX0,intervalY0;
qreal x1, y1, intervalX1,intervalY1;
qreal x2, y2, intervalX2,intervalY2;
QTimer *timer;
int id0, id1, id2;
QPolygonF polygon;
};

#endif // PROJECT_H

/*project.cpp*/
#include "project.h"
#include <QTimer>
#include <QTimerEvent>

Project::Project(QWidget *parent)
: QWidget(parent)
{
ui.setupUi(this);
/*设置第一个场景*/
scene0 = new QGraphicsScene;
scene0->setSceneRect(-300, -300, 600, 600);//场景大小
ballItem = new QGraphicsEllipseItem();
ballItem->setPen(Qt::NoPen);
/*设置球的颜色, 渐变*/
QRadialGradient gradient(QPointF(x0+25, y0+25), 25, QPointF((x0+25)/2,(y0+25)/2));
gradient.setColorAt(0, QColor(255, 255, 255, 255));
gradient.setColorAt(0.25, QColor(0, 255, 255, 180));
gradient.setColorAt(1, QColor(0, 0, 255, 100));
ballItem->setBrush(gradient);
scene0->addItem(ballItem);
ballItem->setRect(QRectF(-25, -25, 50, 50));

ui.viewBall->setRenderHint(QPainter::Antialiasing);
ui.viewBall->setBackgroundBrush(QColor(0x9F, 0x79, 0xEE));
ui.viewBall->setVerticalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
ui.viewBall->setScene(scene0);
ui.viewBall->show();

/*设置第二个场景*/
scene1 = new QGraphicsScene;
scene1->setSceneRect(-300, -300, 600, 600);
rectItem = new QGraphicsRectItem();
rectItem->setPen(Qt::NoPen);
rectItem->setBrush(Qt::darkRed);
scene1->addItem(rectItem);
rectItem->setRect(QRectF(-25, -25, 50, 50));

ui.viewRect->setRenderHint(QPainter::Antialiasing);
ui.viewRect->setBackgroundBrush(QColor(0x9F, 0x79, 0xEE));
ui.viewRect->setVerticalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
ui.viewRect->setScene(scene1);
ui.viewRect->show();

/*设置第三个场景*/
scene2 = new QGraphicsScene;
scene2->setSceneRect(-300, -300, 600, 600);
triAngleItem = new QGraphicsPolygonItem();
triAngleItem->setPen(Qt::NoPen);
triAngleItem->setBrush(Qt::green);
scene2->addItem(triAngleItem);
polygon<<QPointF(-25, -25)<<QPointF(25, -25)<<QPointF(0, 25);
triAngleItem->setPolygon(polygon);

ui.viewTriAngle->setRenderHint(QPainter::Antialiasing);
ui.viewTriAngle->setBackgroundBrush(QColor(0x9F, 0x79, 0xEE));
ui.viewTriAngle->setVerticalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
ui.viewTriAngle->setScene(scene2);
ui.viewTriAngle->show();

x0 = -25;
y0 = -25;
intervalX0 = 0.5;  /*x步长*/
intervalY0 = 0.8; /*y步长*/
x1 = -25;
y1 = -25;
intervalX1 = 0.5;
intervalY1 = 0.8;
x2 = -25;
y2 = -25;
intervalX2 = 0.5;
intervalY2 = 0.8;

connect(ui.buttonStart, SIGNAL(clicked()), this, SLOT(buttonStartClicked()));
connect(ui.buttonPause, SIGNAL(clicked()), this, SLOT(buttonPauseClicked()));
connect(ui.buttonStop, SIGNAL(clicked()), this, SLOT(buttonStopClicked()));
connect(ui.buttonAdd, SIGNAL(clicked()), this, SLOT(buttonAddClicked()));
connect(ui.buttonMinus, SIGNAL(clicked()), this, SLOT(buttonMinusClicked()));

}

void Project::timerEvent( QTimerEvent *event )
{
if(ui.tab_4->currentIndex() == 0)//第二个场景
{
QRadialGradient gradient(QPointF(x0+25, y0+25), 25, QPointF((x0+25)/2,(y0+25)/2));
gradient.setColorAt(0, QColor(255, 255, 255, 255));
gradient.setColorAt(0.25, QColor(0, 255, 255, 180));
gradient.setColorAt(1, QColor(0, 0, 255, 100));
ballItem->setBrush(gradient);

if(event->timerId() == id0)/*第一个定时器*/
{
ballItem->setRect(QRectF(x0, y0, 50, 50));
x0 +=intervalX0;//运动
y0 +=intervalY0;

/*判断反弹*/
if(x0+50 > 292)
{
x0 = 292 - (x0+50-292)-50;
intervalX0 = -intervalX0;
}
if(y0+50 >284)
{
y0 = 284-(y0+50-284)-50;
intervalY0 = -intervalY0;
}
if(x0 <-290)
{
x0= -290-x0-290;
intervalX0 = -intervalX0;
}
if(y0 <-290)
{
y0 = -290-y0-290;
intervalY0 = -intervalY0;
}
update();
}
}
if(ui.tab_4->currentIndex() == 1)//第二个场景
{

if(event->timerId() == id1)/*第二个定时器*/
{
rectItem->setRect(QRectF(x1, y1, 50, 50));
x1 +=intervalX1;
y1 +=intervalY1;
if(x1+50 > 292)
{
x1 = 292 - (x1+50-292)-50;
intervalX1 = -intervalX1;
}
if(y1+50 >284)
{
y1 = 284-(y1+50-284)-50;
intervalY1 = -intervalY1;
}
if(x1 <-290)
{
x1 = -290-x1-290;
intervalX1 = -intervalX1;
}
if(y1 <-290)
{
y1 = -290-y1-290;
intervalY1 = -intervalY1;
}

update();
}
}

if(ui.tab_4->currentIndex() == 2)<span style="font-family: Arial, Helvetica, sans-serif;">//第三个场景</span>
{
if(event->timerId() == id2)//第三个定时器
{
update();

x2 +=intervalX2;
y2 +=intervalY2;
if(x2+50 > 292)
{
x2 = 292 - (x2+50-292)-50;
intervalX2 = -intervalX2;
}
if(y2+50 >284)
{
y2 = 284-(y2+50-284)-50;
intervalY2 = -intervalY2;
}
if(x2 <-290)
{
x2 = -290-x2-290;
intervalX2 = -intervalX2;
}
if(y2 <-290)
{
y2 = -290-y2-290;
intervalY2 = -intervalY2;
}
polygon.clear();
polygon<<QPointF(x2, y2)<<QPointF(x2+50, y2)<<QPointF(x2+25, y2+50);
triAngleItem->setPolygon(polygon);

}
}
}

void Project::buttonStartClicked()//开始按钮,启动对应定时器
{
if(ui.tab_4->currentIndex() == 0)
id0 = startTimer(10);
if(ui.tab_4->currentIndex() == 1)
id1 = startTimer(10);
if(ui.tab_4->currentIndex() == 2)
id2 = startTimer(10);

}

void Project::buttonPauseClicked()//暂停按钮
{
if(ui.tab_4->currentIndex() == 0)
killTimer(id0);
if(ui.tab_4->currentIndex() == 1)
killTimer(id1);
if(ui.tab_4->currentIndex() == 2)
killTimer(id2);
}

void Project::buttonStopClicked()//停止按钮, 恢复初始化状态
{
if(ui.tab_4->currentIndex() == 0)
{
killTimer(id0);
scene0->removeItem(ballItem);
x0 = -25;
y0 = -25;
intervalX0 = 0.5;
intervalY0 = 0.8;
ballItem = new QGraphicsEllipseItem();
ballItem->setPen(Qt::NoPen);
ballItem->setBrush(Qt::darkRed);
scene0->addItem(ballItem);
ballItem->setRect(QRectF(x0, y0, 50, 50));
}

if(ui.tab_4->currentIndex() == 1)
{
killTimer(id1);
scene1->removeItem(rectItem);
x1 = -25;
y1 = -25;
intervalX1 = 0.5;
intervalY1 = 0.8;
rectItem = new QGraphicsRectItem();
rectItem->setPen(Qt::NoPen);
rectItem->setBrush(Qt::darkRed);
scene1->addItem(rectItem);
rectItem->setRect(QRectF(x1, y1, 50, 50));
}

if(ui.tab_4->currentIndex() == 2)
{
killTimer(id2);
scene0->removeItem(triAngleItem);
x2 = -25;
y2 = -25;
intervalX2 = 0.5;
intervalY2 = 0.8;
triAngleItem = new QGraphicsPolygonItem();
triAngleItem->setPen(Qt::NoPen);
triAngleItem->setBrush(Qt::darkRed);
scene2->addItem(triAngleItem);
polygon<<QPointF(x2, y2)<<QPointF(x2+50, y2)<<QPointF(x2+25, y2+50);
triAngleItem->setPolygon(polygon);
}
}

void Project::buttonAddClicked()//加速,增加步长
{
if(ui.tab_4->currentIndex() == 0)
{
intervalX0 *= 1.5;
intervalY0 *= 1.5;
}
if(ui.tab_4->currentIndex() == 1)
{
intervalX1 *= 1.5;
intervalY1 *= 1.5;
}
if(ui.tab_4->currentIndex() == 2)
{
intervalX2 *= 1.5;
intervalY2 *= 1.5;
}
}

void Project::buttonMinusClicked()//减速, 减小步长
{
if(ui.tab_4->currentIndex() == 0)
{
intervalX0 *= 1/1.5;
intervalY0 *= 1/1.5;
}
if(ui.tab_4->currentIndex() == 1)
{
intervalX1 *= 1/1.5;
intervalY1 *= 1/1.5;
}
if(ui.tab_4->currentIndex() == 2)
{
intervalX2 *= 1/1.5;
intervalY2 *= 1/1.5;
}
}