Qt Reference Documentation

torpedo.cpp Example File

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 #include "torpedo.h"
 #include "pixmapitem.h"
 #include "boat.h"
 #include "graphicsscene.h"
 #include "animationmanager.h"
 #include "qanimationstate.h"

 #include <QtCore/QPropertyAnimation>
 #include <QtCore/QStateMachine>
 #include <QtCore/QFinalState>

 Torpedo::Torpedo() : PixmapItem(QString::fromLatin1("torpedo"),GraphicsScene::Big),

 void Torpedo::launch()
     QPropertyAnimation *launchAnimation = new QPropertyAnimation(this, "pos");
     launchAnimation->setEndValue(QPointF(x(),qobject_cast<GraphicsScene *>(scene())->sealLevel() - 15));
     connect(this,SIGNAL(torpedoExploded()), launchAnimation, SLOT(stop()));

     //We setup the state machine of the torpedo
     QStateMachine *machine = new QStateMachine(this);

     //This state is when the launch animation is playing
     QAnimationState *launched = new QAnimationState(machine);

     QFinalState *final = new QFinalState(machine);


     //### Add a nice animation when the torpedo is destroyed
     launched->addTransition(this, SIGNAL(torpedoExploded()),final);

     //If the animation is finished, then we move to the final state
     launched->addTransition(launched, SIGNAL(animationFinished()), final);

     //The machine has finished to be executed, then the boat is dead
     connect(machine,SIGNAL(finished()),this, SIGNAL(torpedoExecutionFinished()));


 void Torpedo::setCurrentSpeed(int speed)
     if (speed < 0) {
         qWarning("Torpedo::setCurrentSpeed : The speed is invalid");
     currentSpeed = speed;

 void Torpedo::onAnimationLaunchValueChanged(const QVariant &)
     foreach (QGraphicsItem *item , collidingItems(Qt::IntersectsItemBoundingRect)) {
         if (Boat *b = qgraphicsitem_cast<Boat*>(item))

 void Torpedo::destroy()
     emit torpedoExploded();

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