cannon.cpp

我在我的EP9315上写的两个QT程序

#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;
 timerCount = 0;
 autoShootTimer = new QTimer( this, "movement handler" );
 connect( autoShootTimer,SIGNAL(timeout()), this,SLOT(moveShot()) );
 shoot_ang = 0 ;
 shoot_f = 0;
 target = QPoint (0, 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 ( newton==f) 
    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::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( 30 + rand()%100,20 + rand()%100 );
  //target = QPoint( 100 ,120 );
  repaint( r.unite(targetRect() ) );
}

void CannonField::moveShot()
{
  QRegion r( shotRect() );
  timerCount++;
  
  QRect shotR = shotRect();
  if( shotR.intersects( targetRect() ) ){
   autoShootTimer->stop();
   emit hit(); 
   newTarget();
  }
   
  else if( shotR.x() > width() || shotR.y()>height() ){
       autoShootTimer->stop();
       emit missed();
       newTarget();
       }
     else{
       r=r.unite( QRegion( shotR ) );
      // newTarget();
       }  
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 );
  if ( updateR.intersects( targetRect() ) )
   paintTarget( &p );
}

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() );

}

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 ( ) );
  pix.fill ( this, cr.topLeft ( ) );
  
  QPainter tmp( & pix, this );
  tmp.setBrush( blue );
  tmp.setPen( NoPen );
  tmp.translate( 0, pix.height( )-1 );
 // p.translate( pix.width( )-1, pix.height( )-1 );
  tmp.drawPie( QRect( -35, -35, 70, 70 ), 0, 90*16 );
  tmp.rotate( -ang );
  tmp.drawRect( QRect( 33, -4, 15, 8 ) );
  tmp.end();
  
  //p.begin ( this );
  p->drawPixmap ( cr.topLeft() , pix );
    
}

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

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 );

}