cannon.cpp

qt开发的一个简单的例程

#include "cannon.h"
#include <qpainter.h>
#include <qpixmap.h>
#include <qtimer.h>
#include <qdatetime.h>

#include <math.h>
#include <stdlib.h>

CannonField::CannonField(QWidget *parent,const char *name)
	: QWidget(parent,name)
{
	ang = 45;
	f = 0;
	timeCount = 0;
	autoShootTimer = new QTimer(this,"movement handler");
	connect(autoShootTimer,SIGNAL(timeout()),
		this,SLOT(moveShot()));
	shoot_ang = 0;
	shoot_f = 0;
	setPalette(QPalette(QColor(250,250,200)));
	newTarget();
}

void CannonField::setAngle(int degrees)
{
	if(degrees<5)
		degrees=5;
	if(degrees>70)
		degrees=70;
	if(ang==degrees)
		return;
	ang=degrees;
	repaint(cannonRect(),FALSE);
	emit angleChanged(ang);
}

void CannonField::setForce(int newton)
{
	if(newton<0)
		newton = 0;
	if(f==newton)
		return;
	f = newton;
	emit forceChanged(f);
}

void CannonField::shoot()
{
	if(isShooting())
		return;
	timeCount = 0;
	shoot_ang = ang;
	shoot_f = f;
	autoShootTimer->start(50);
	emit canShoot(FALSE);
}

bool CannonField::isShooting() const
{
	return autoShootTimer->isActive();
}

void CannonField::restartGame()
{
	if(isShooting())
		autoShootTimer->stop();
	gameEnded = FALSE;
	emit canShoot(TRUE);
}

void CannonField::setGameOver()
{
	if(gameEnded)
		return;
	if(isShooting())
		autoShootTimer->stop();
	gameEnded = TRUE;
	repaint();
}


void CannonField::newTarget()
{
	static bool first_time = TRUE;
	if(first_time){
		first_time = FALSE;
		QTime midnight(0,0,0);
		srand(midnight.secsTo(QTime::currentTime()));
	}
	QRegion r(targetRect());
	target = QPoint(200 + rand()%190,
			10 + rand()%255);
	repaint(r.unite(targetRect()));
}

void CannonField::moveShot()
{
	QRegion r(LastShotRect);
	LastShotRect = shotRect();

	timeCount++;	
	QRect shotR = shotRect();  // abtain the updated shotRect
	if(shotR.intersects(targetRect())){
		autoShootTimer->stop();
		emit canShoot(TRUE);
		emit hit();
	}else if( shotR.x() > width() || shotR.y() > height() ){
		 autoShootTimer->stop();
		 emit missed();
		 emit canShoot(TRUE);
	      }
        r = r.unite(QRegion(shotR));
	repaint(r);
//	repaint(shotR);
}

const QRect barrelRect(33,-4,15,8);

void CannonField::paintCannon(QPainter* p)
{
	//if(!e->rect().intersects(cannonRect()))
	//	return;
	QRect cr = cannonRect();
	QPixmap pix(cr.size());
//	QPixmap pix;//  (cr.width(),cr.height(),-1);
	pix.fill(this,cr.topLeft());
	
	QPainter tmp(&pix);
	tmp.setBrush(blue);
	tmp.setPen(NoPen);

	tmp.translate(0,pix.height()-1);
	tmp.drawPie(QRect(-35,-35,70,70),0,90*16);
	tmp.rotate(-ang);
	tmp.drawRect(barrelRect);
	tmp.end();	
//	p.begin(this);
	p->drawPixmap(cr.topLeft(),pix);
/*
//	QString s = "Angle = " + QString::number(ang);
	QPainter p(this);
//	p.drawText(200,200,s);
	p.setBrush(blue);
	p.setPen(NoPen);
	p.translate(0,rect().bottom());
	p.drawPie(QRect(-35,-35,70,70),0,90*16);
	p.rotate(-ang);
	p.drawRect(QRect(33,-4,15,8));
*/
}

void CannonField::paintShot(QPainter* p)
{
	p->setBrush(black);
	p->setPen(NoPen);
	p->drawRect(shotRect());
}

void CannonField::paintTarget(QPainter* p)
{
	p->setBrush(red);
	p->setPen(black);
	p->drawRect(targetRect());
}

void CannonField::paintEvent(QPaintEvent* e)
{
	QRect updataR = e->rect();
	QPainter p(this);
		
	if(gameEnded){
		p.setPen(black);
		p.setFont(QFont("Courier",48,QFont::Bold));
		p.drawText(rect(),AlignCenter,"Game Over");
	}
	if(updataR.intersects(cannonRect()))
		paintCannon(&p);
	if(autoShootTimer->isActive()&&updataR.intersects(shotRect()))
		paintShot(&p);
	if(updataR.intersects(targetRect()))
		paintTarget(&p);
}

QRect CannonField::cannonRect() const
{
	QRect r(0,0,50,50);
	r.moveBottomLeft(rect().bottomLeft());
	return r;
}

QRect CannonField::shotRect() const
{
	const double gravity = 4;
	double time = timeCount/4.0;
	double velocity = shoot_f;
	double radians = shoot_ang*3.1415926/180;

	double velx = velocity*cos(radians);
	double vely = velocity*sin(radians);
	double x0 = barrelRect.right() * cos(radians);
	double y0 = barrelRect.right() * sin(radians);
	double x = x0 + velx*time;
	double y = y0 + vely*time - 0.5*gravity*time*time;

	QRect r = QRect(0,0,6,6);
	r.moveCenter(QPoint(qRound(x),height()-1-qRound(y)));
	return r;
}

QRect CannonField::targetRect() const
{
	QRect r(0,0,20,10);
	r.moveCenter(QPoint(target.x(),height()-1-target.y()));
	return r;
}

QSizePolicy CannonField::sizePolicy() const
{
	return QSizePolicy(QSizePolicy::Expanding,QSizePolicy::Expanding);
}