cannonfield.cpp Example File
tutorial/t14/cannonfield.cpp
/****************************************************************************
**
** Copyright (C) 2005-2006 Trolltech AS. All rights reserved.
**
** This file is part of the documentation of the Qt Toolkit.
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** and appearing in the file LICENSE.GPL included in the packaging of
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#include <QDateTime>
#include <QMouseEvent>
#include <QPaintEvent>
#include <QPainter>
#include <QTimer>
#include <math.h>
#include <stdlib.h>
#include "cannonfield.h"
CannonField::CannonField(QWidget *parent)
: QWidget(parent)
{
currentAngle = 45;
currentForce = 0;
timerCount = 0;
autoShootTimer = new QTimer(this);
connect(autoShootTimer, SIGNAL(timeout()), this, SLOT(moveShot()));
shootAngle = 0;
shootForce = 0;
target = QPoint(0, 0);
gameEnded = false;
barrelPressed = false;
setPalette(QPalette(QColor(250, 250, 200)));
setAutoFillBackground(true);
newTarget();
}
void CannonField::setAngle(int angle)
{
if (angle < 5)
angle = 5;
if (angle > 70)
angle = 70;
if (currentAngle == angle)
return;
currentAngle = angle;
update(cannonRect());
emit angleChanged(currentAngle);
}
void CannonField::setForce(int force)
{
if (force < 0)
force = 0;
if (currentForce == force)
return;
currentForce = force;
emit forceChanged(currentForce);
}
void CannonField::shoot()
{
if (isShooting())
return;
timerCount = 0;
shootAngle = currentAngle;
shootForce = currentForce;
autoShootTimer->start(5);
emit canShoot(false);
}
void CannonField::newTarget()
{
static bool firstTime = true;
if (firstTime) {
firstTime = false;
QTime midnight(0, 0, 0);
srand(midnight.secsTo(QTime::currentTime()));
}
target = QPoint(200 + rand() % 190, 10 + rand() % 255);
update();
}
void CannonField::setGameOver()
{
if (gameEnded)
return;
if (isShooting())
autoShootTimer->stop();
gameEnded = true;
update();
}
void CannonField::restartGame()
{
if (isShooting())
autoShootTimer->stop();
gameEnded = false;
update();
emit canShoot(true);
}
void CannonField::moveShot()
{
QRegion region = shotRect();
++timerCount;
QRect shotR = shotRect();
if (shotR.intersects(targetRect())) {
autoShootTimer->stop();
emit hit();
emit canShoot(true);
} else if (shotR.x() > width() || shotR.y() > height()
|| shotR.intersects(barrierRect())) {
autoShootTimer->stop();
emit missed();
emit canShoot(true);
} else {
region = region.unite(shotR);
}
update(region);
}
void CannonField::mousePressEvent(QMouseEvent *event)
{
if (event->button() != Qt::LeftButton)
return;
if (barrelHit(event->pos()))
barrelPressed = true;
}
void CannonField::mouseMoveEvent(QMouseEvent *event)
{
if (!barrelPressed)
return;
QPoint pos = event->pos();
if (pos.x() <= 0)
pos.setX(1);
if (pos.y() >= height())
pos.setY(height() - 1);
double rad = atan(((double)rect().bottom() - pos.y()) / pos.x());
setAngle(qRound(rad * 180 / 3.14159265));
}
void CannonField::mouseReleaseEvent(QMouseEvent *event)
{
if (event->button() == Qt::LeftButton)
barrelPressed = false;
}
void CannonField::paintEvent(QPaintEvent * /* event */)
{
QPainter painter(this);
if (gameEnded) {
painter.setPen(Qt::black);
painter.setFont(QFont("Courier", 48, QFont::Bold));
painter.drawText(rect(), Qt::AlignCenter, tr("Game Over"));
}
paintCannon(painter);
paintBarrier(painter);
if (isShooting())
paintShot(painter);
if (!gameEnded)
paintTarget(painter);
}
void CannonField::paintShot(QPainter &painter)
{
painter.setPen(Qt::NoPen);
painter.setBrush(Qt::black);
painter.drawRect(shotRect());
}
void CannonField::paintTarget(QPainter &painter)
{
painter.setPen(Qt::black);
painter.setBrush(Qt::red);
painter.drawRect(targetRect());
}
void CannonField::paintBarrier(QPainter &painter)
{
painter.setPen(Qt::black);
painter.setBrush(Qt::yellow);
painter.drawRect(barrierRect());
}
const QRect barrelRect(30, -5, 20, 10);
void CannonField::paintCannon(QPainter &painter)
{
painter.setPen(Qt::NoPen);
painter.setBrush(Qt::blue);
painter.save();
painter.translate(0, height());
painter.drawPie(QRect(-35, -35, 70, 70), 0, 90 * 16);
painter.rotate(-currentAngle);
painter.drawRect(barrelRect);
painter.restore();
}
QRect CannonField::cannonRect() const
{
QRect result(0, 0, 50, 50);
result.moveBottomLeft(rect().bottomLeft());
return result;
}
QRect CannonField::shotRect() const
{
const double gravity = 4;
double time = timerCount / 20.0;
double velocity = shootForce;
double radians = shootAngle * 3.14159265 / 180;
double velx = velocity * cos(radians);
double vely = velocity * sin(radians);
double x0 = (barrelRect.right() + 5) * cos(radians);
double y0 = (barrelRect.right() + 5) * sin(radians);
double x = x0 + velx * time;
double y = y0 + vely * time - 0.5 * gravity * time * time;
QRect result(0, 0, 6, 6);
result.moveCenter(QPoint(qRound(x), height() - 1 - qRound(y)));
return result;
}
QRect CannonField::targetRect() const
{
QRect result(0, 0, 20, 10);
result.moveCenter(QPoint(target.x(), height() - 1 - target.y()));
return result;
}
QRect CannonField::barrierRect() const
{
return QRect(145, height() - 100, 15, 99);
}
bool CannonField::barrelHit(const QPoint &pos) const
{
QMatrix matrix;
matrix.translate(0, height());
matrix.rotate(-currentAngle);
matrix = matrix.inverted();
return barrelRect.contains(matrix.map(pos));
}
bool CannonField::isShooting() const
{
return autoShootTimer->isActive();
}
QSize CannonField::sizeHint() const
{
return QSize(400, 300);
}
