include Math require 'Qt' class CannonField < Qt::Widget signals 'angleChanged(int)', 'forceChanged(int)' slots 'setAngle(int)', 'setForce(int)', 'shoot()', 'moveShot()' def initialize(parent, name) super @ang = 45 @f = 0 @timerCount = 0; @autoShootTimer = Qt::Timer.new( self, 'movement handler' ) connect( @autoShootTimer, SIGNAL('timeout()'), self, SLOT('moveShot()') ); @shoot_ang = 0 @shoot_f = 0 setPalette( Qt::Palette.new( Qt::Color.new( 250, 250, 200) ) ) @barrelRect = Qt::Rect.new(33, -4, 15, 8) end def setAngle( degrees ) if degrees < 5 degrees = 5 elsif degrees > 70 degrees = 70 end if @ang == degrees return end @ang = degrees repaint( cannonRect(), false ) emit angleChanged( @ang ) end def setForce( newton ) if newton < 0 newton = 0 end if @f == newton return end @f = newton emit forceChanged( @f ) end def shoot() if @autoShootTimer.isActive() return end; @timerCount = 0 @shoot_ang = @ang @shoot_f = @f @autoShootTimer.start( 50 ) end def moveShot() r = Qt::Region.new( shotRect() ) @timerCount += 1 shotR = shotRect() if shotR.x() > width() || shotR.y() > height() @autoShootTimer.stop() else r = r.unite( Qt::Region.new( shotR ) ) end repaint( r ) end def paintEvent( e ) updateR = e.rect() p = Qt::Painter.new( self ) if updateR.intersects( cannonRect() ) paintCannon( p ) end if @autoShootTimer.isActive() && updateR.intersects( shotRect() ) paintShot( p ) end p.end() end def paintShot( p ) p.setBrush( black ) p.setPen( Qt::NoPen ) p.drawRect( shotRect() ) end def paintCannon(p) cr = cannonRect() pix = Qt::Pixmap.new( cr.size() ) pix.fill( self, cr.topLeft() ) tmp = Qt::Painter.new( pix ) tmp.setBrush( blue ) tmp.setPen( Qt::NoPen ) tmp.translate( 0, pix.height() - 1 ) tmp.drawPie( Qt::Rect.new(-35, -35, 70, 70), 0, 90*16 ) tmp.rotate( - @ang ) tmp.drawRect( @barrelRect ) tmp.end() p.drawPixmap(cr.topLeft(), pix ) end def cannonRect() r = Qt::Rect.new( 0, 0, 50, 50) r.moveBottomLeft( rect().bottomLeft() ) return r end def shotRect() gravity = 4.0 time = @timerCount / 4.0 velocity = @shoot_f radians = @shoot_ang*3.14159265/180.0 velx = velocity*cos( radians ) vely = velocity*sin( radians ) x0 = ( @barrelRect.right() + 5.0 )*cos(radians) y0 = ( @barrelRect.right() + 5.0 )*sin(radians) x = x0 + velx*time y = y0 + vely*time - 0.5*gravity*time*time r = Qt::Rect.new( 0, 0, 6, 6 ); r.moveCenter( Qt::Point.new( x.round, height() - 1 - y.round ) ) return r end def sizePolicy() return Qt::SizePolicy.new( Qt::SizePolicy::Expanding, Qt::SizePolicy::Expanding ) end end