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/****************************************************************
**
** Implementation CannonField class, Qt tutorial 11
**
****************************************************************/
#include "cannon.h"
#include <qtimer.h>
#include <qpainter.h>
#include <qpixmap.h>
#include <math.h>
CannonField::CannonField( QWidget *parent, const char *name )
: QWidget( parent, name )
{
ang = 45;
f = 0;
timerCount = 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) ) );
}
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 ( autoShootTimer->isActive() )
return;
timerCount = 0;
shoot_ang = ang;
shoot_f = f;
autoShootTimer->start( 50 );
}
void CannonField::moveShot()
{
QRegion r( shotRect() );
timerCount++;
QRect shotR = shotRect();
if ( shotR.x() > width() || shotR.y() > height() )
autoShootTimer->stop();
else
r = r.unite( QRegion( shotR ) );
repaint( r );
}
void CannonField::paintEvent( QPaintEvent *e )
{
QRect updateR = e->rect();
QPainter p( this );
if ( updateR.intersects( cannonRect() ) )
paintCannon( &p );
if ( autoShootTimer->isActive() &&
updateR.intersects( shotRect() ) )
paintShot( &p );
}
void CannonField::paintShot( QPainter *p )
{
p->setBrush( black );
p->setPen( NoPen );
p->drawRect( shotRect() );
}
const QRect barrelRect(33, -4, 15, 8);
void CannonField::paintCannon( QPainter *p )
{
QRect cr = cannonRect();
QPixmap pix( cr.size() );
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->drawPixmap( cr.topLeft(), pix );
}
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 = timerCount / 4.0;
double velocity = shoot_f;
double radians = shoot_ang*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 r = QRect( 0, 0, 6, 6 );
r.moveCenter( QPoint( qRound(x), height() - 1 - qRound(y) ) );
return r;
}
QSizePolicy CannonField::sizePolicy() const
{
return QSizePolicy( QSizePolicy::Expanding, QSizePolicy::Expanding );
}
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