- Qt 5.5
- Qt Widgets
- Sub-Attaq
- torpedo.cpp Example File
- Qt 5.5.1 Reference Documentation

# torpedo.cpp Example File

animation/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();
    }