Qt 4.8: torpedo.cpp Example File (demos/sub-attaq/torpedo.cpp)

Qt Reference Documentation

# torpedo.cpp Example File

demos/sub-attaq/torpedo.cpp

     /****************************************************************************
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     //Own
     #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),
         currentSpeed(0)
     {
         setZValue(2);
     }

     void Torpedo::launch()
     {
         QPropertyAnimation *launchAnimation = new QPropertyAnimation(this, "pos");
         AnimationManager::self()->registerAnimation(launchAnimation);
         launchAnimation->setEndValue(QPointF(x(),qobject_cast<GraphicsScene *>(scene())->sealLevel() - 15));
         launchAnimation->setEasingCurve(QEasingCurve::InQuad);
         launchAnimation->setDuration(y()/currentSpeed*10);
         connect(launchAnimation,SIGNAL(valueChanged(QVariant)),this,SLOT(onAnimationLaunchValueChanged(QVariant)));
         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);
         launched->setAnimation(launchAnimation);

         //End
         QFinalState *final = new QFinalState(machine);

         machine->setInitialState(launched);

         //### 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()));

         machine->start();
     }

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

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

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