Change name of "errorstate" example to "tankgame"

The error state is not a big enough part of the example to justify naming it
after it.

11 files changed, 878 insertions, 0 deletions

diff --git a/examples/statemachine/tankgame/gameitem.cpp b/examples/statemachine/tankgame/gameitem.cpp
new file mode 100644
index 0000000..1a2af71
--- /dev/null
+++ b/examples/statemachine/tankgame/gameitem.cpp
@@ -0,0 +1,88 @@
+#include "gameitem.h"
+
+#include <QGraphicsScene>
+#include <QDebug>
+
+GameItem::GameItem(QObject *parent) : QObject(parent)
+{
+}
+
+QPointF GameItem::tryMove(const QPointF &requestedPosition, QLineF *collidedLine, 
+                          QGraphicsItem **collidedItem) const
+{
+    QLineF movementPath(pos(), requestedPosition);    
+
+    qreal cannonLength = 0.0;
+    {
+        QPointF p1 = boundingRect().center();
+        QPointF p2 = QPointF(boundingRect().right() + 10.0, p1.y());
+
+        cannonLength = QLineF(mapToScene(p1), mapToScene(p2)).length();
+    }
+
+    movementPath.setLength(movementPath.length() + cannonLength);
+
+    QRectF boundingRectPath(QPointF(qMin(movementPath.x1(), movementPath.x2()), qMin(movementPath.y1(), movementPath.y2())),
+                            QPointF(qMax(movementPath.x1(), movementPath.x2()), qMax(movementPath.y1(), movementPath.y2())));
+
+    QList<QGraphicsItem *> itemsInRect = scene()->items(boundingRectPath, Qt::IntersectsItemBoundingRect);
+
+    QPointF nextPoint = requestedPosition;
+    QRectF sceneRect = scene()->sceneRect();
+
+    foreach (QGraphicsItem *item, itemsInRect) {
+        if (item == static_cast<const QGraphicsItem *>(this))
+            continue; 
+
+        QPolygonF mappedBoundingRect = item->mapToScene(item->boundingRect());
+        for (int i=0; i<mappedBoundingRect.size(); ++i) {
+            QPointF p1 = mappedBoundingRect.at(i == 0 ? mappedBoundingRect.size()-1 : i-1);
+            QPointF p2 = mappedBoundingRect.at(i);
+
+            QLineF rectLine(p1, p2);
+            QPointF intersectionPoint;
+            QLineF::IntersectType intersectType = movementPath.intersect(rectLine, &intersectionPoint);
+
+            if (intersectType == QLineF::BoundedIntersection) {
+                movementPath.setP2(intersectionPoint);
+                movementPath.setLength(movementPath.length() - cannonLength);
+                nextPoint = movementPath.p2();
+
+                if (collidedLine != 0)
+                    *collidedLine = rectLine;
+
+                if (collidedItem != 0)
+                    *collidedItem = item;
+            }
+        }
+    }
+
+
+    // Don't go outside of map
+    if (nextPoint.x() < sceneRect.left()) {
+        nextPoint.rx() = sceneRect.left();
+        if (collidedLine != 0)
+            *collidedLine = QLineF(scene()->sceneRect().topLeft(), scene()->sceneRect().bottomLeft());
+    }
+    
+    if (nextPoint.x() > sceneRect.right()) {
+        nextPoint.rx() = sceneRect.right();
+        if (collidedLine != 0)
+            *collidedLine = QLineF(scene()->sceneRect().topRight(), scene()->sceneRect().bottomRight());        
+    }
+    
+    if (nextPoint.y() < sceneRect.top()) {
+        nextPoint.ry() = sceneRect.top();
+        if (collidedLine != 0)
+            *collidedLine = QLineF(scene()->sceneRect().topLeft(), scene()->sceneRect().topRight());
+    }
+    
+    if (nextPoint.y() > sceneRect.bottom()) {
+        nextPoint.ry() = sceneRect.bottom();
+        if (collidedLine != 0)
+            *collidedLine = QLineF(scene()->sceneRect().bottomLeft(), scene()->sceneRect().bottomRight());
+    }
+
+    return nextPoint;
+}
+
diff --git a/examples/statemachine/tankgame/gameitem.h b/examples/statemachine/tankgame/gameitem.h
new file mode 100644
index 0000000..43b8785
--- /dev/null
+++ b/examples/statemachine/tankgame/gameitem.h
@@ -0,0 +1,23 @@
+#ifndef GAMEITEM_H
+#define GAMEITEM_H
+
+#include <QGraphicsItem>
+
+class QLineF;
+class GameItem: public QObject, public QGraphicsItem
+{
+    Q_OBJECT
+public:
+    enum { Type = UserType + 1 };
+    int type() const { return Type; }
+
+    GameItem(QObject *parent = 0);
+
+    virtual void idle(qreal elapsed) = 0;
+
+protected:
+    QPointF tryMove(const QPointF &requestedPosition, QLineF *collidedLine = 0, 
+        QGraphicsItem **collidedItem = 0) const;
+};
+
+#endif
diff --git a/examples/statemachine/tankgame/main.cpp b/examples/statemachine/tankgame/main.cpp
new file mode 100644
index 0000000..26fc1bb
--- /dev/null
+++ b/examples/statemachine/tankgame/main.cpp
@@ -0,0 +1,12 @@
+#include <QApplication>
+#include "mainwindow.h"
+
+int main(int argc, char **argv)
+{
+    QApplication app(argc, argv);
+
+    MainWindow mainWindow;
+    mainWindow.show();
+
+    return app.exec();
+}
diff --git a/examples/statemachine/tankgame/mainwindow.cpp b/examples/statemachine/tankgame/mainwindow.cpp
new file mode 100644
index 0000000..3bc9bbe
--- /dev/null
+++ b/examples/statemachine/tankgame/mainwindow.cpp
@@ -0,0 +1,264 @@
+#include "mainwindow.h"
+#include "tankitem.h"
+#include "rocketitem.h"
+#include "plugin.h"
+
+#include <QStateMachine>
+#include <QGraphicsView>
+#include <QAction>
+#include <QMenuBar>
+#include <QState>
+#include <QHistoryState>
+#include <QTimer>
+#include <QFileDialog>
+#include <QPluginLoader>
+#include <QApplication>
+#include <QInputDialog>
+#include <QMessageBox>
+
+MainWindow::MainWindow(QWidget *parent)
+    : QMainWindow(parent), m_scene(0), m_machine(0), m_runningState(0), m_started(false)
+{
+    init();
+}
+
+MainWindow::~MainWindow()
+{
+}
+
+void MainWindow::addWall(const QRectF &wall)
+{
+    QGraphicsRectItem *item = new QGraphicsRectItem;
+    item->setRect(wall);
+    item->setBrush(Qt::darkGreen);
+    item->setPen(QPen(Qt::black, 0));
+
+    m_scene->addItem(item);
+}
+
+void MainWindow::init()
+{
+    setWindowTitle("Pluggable Tank Game");
+
+    QGraphicsView *view = new QGraphicsView(this);
+    view->setRenderHints(QPainter::Antialiasing);
+    setCentralWidget(view);
+
+    m_scene = new QGraphicsScene(this);
+    view->setScene(m_scene);
+
+    QRectF sceneRect = QRectF(-200.0, -200.0, 400.0, 400.0);
+    m_scene->setSceneRect(sceneRect);
+
+    {
+        TankItem *item = new TankItem(this);
+
+        item->setPos(m_scene->sceneRect().topLeft() + QPointF(15.0, 15.0));
+        item->setDirection(45.0);
+        item->setColor(Qt::red);
+
+        m_spawns.append(item);
+    }
+
+    {
+        TankItem *item = new TankItem(this);
+
+        item->setPos(m_scene->sceneRect().topRight() + QPointF(-15.0, 15.0));
+        item->setDirection(135.0);
+        item->setColor(Qt::green);
+
+        m_spawns.append(item);
+    }
+
+    {
+        TankItem *item = new TankItem(this);
+
+        item->setPos(m_scene->sceneRect().bottomRight() + QPointF(-15.0, -15.0));
+        item->setDirection(225.0);
+        item->setColor(Qt::blue);
+
+        m_spawns.append(item);
+    }
+
+    {
+        TankItem *item = new TankItem(this);
+
+        item->setPos(m_scene->sceneRect().bottomLeft() + QPointF(15.0, -15.0));
+        item->setDirection(315.0);
+        item->setColor(Qt::yellow);
+
+        m_spawns.append(item);
+    }
+
+    QPointF centerOfMap = sceneRect.center();
+
+    addWall(QRectF(centerOfMap + QPointF(-50.0, -60.0), centerOfMap + QPointF(50.0, -50.0)));
+    addWall(QRectF(centerOfMap - QPointF(-50.0, -60.0), centerOfMap - QPointF(50.0, -50.0)));
+    addWall(QRectF(centerOfMap + QPointF(-50.0, -50.0), centerOfMap + QPointF(-40.0, 50.0)));
+    addWall(QRectF(centerOfMap - QPointF(-50.0, -50.0), centerOfMap - QPointF(-40.0, 50.0)));
+   
+    addWall(QRectF(sceneRect.topLeft() + QPointF(sceneRect.width() / 2.0 - 5.0, -10.0),
+                   sceneRect.topLeft() + QPointF(sceneRect.width() / 2.0 + 5.0, 100.0)));
+    addWall(QRectF(sceneRect.bottomLeft() + QPointF(sceneRect.width() / 2.0 - 5.0, 10.0),
+                   sceneRect.bottomLeft() + QPointF(sceneRect.width() / 2.0 + 5.0, -100.0)));
+    addWall(QRectF(sceneRect.topLeft() + QPointF(-10.0, sceneRect.height() / 2.0 - 5.0),
+                   sceneRect.topLeft() + QPointF(100.0, sceneRect.height() / 2.0 + 5.0)));
+    addWall(QRectF(sceneRect.topRight() + QPointF(10.0, sceneRect.height() / 2.0 - 5.0),
+                   sceneRect.topRight() + QPointF(-100.0, sceneRect.height() / 2.0 + 5.0)));
+
+
+    QAction *addTankAction = menuBar()->addAction("&Add tank");   
+    QAction *runGameAction = menuBar()->addAction("&Run game");    
+    runGameAction->setObjectName("runGameAction");
+    QAction *stopGameAction = menuBar()->addAction("&Stop game");        
+    menuBar()->addSeparator();
+    QAction *quitAction = menuBar()->addAction("&Quit");
+    
+    connect(addTankAction, SIGNAL(triggered()), this, SLOT(addTank()));
+    connect(quitAction, SIGNAL(triggered()), this, SLOT(close()));
+        
+    m_machine = new QStateMachine(this);    
+    QState *stoppedState = new QState(m_machine->rootState());        
+    stoppedState->setObjectName("stoppedState");
+    stoppedState->assignProperty(runGameAction, "enabled", true);
+    stoppedState->assignProperty(stopGameAction, "enabled", false);
+    stoppedState->assignProperty(this, "started", false);
+    m_machine->setInitialState(stoppedState);
+
+    QState *spawnsAvailable = new QState(stoppedState);
+    spawnsAvailable->setObjectName("spawnsAvailable");
+    spawnsAvailable->assignProperty(addTankAction, "enabled", true);
+
+    QState *noSpawnsAvailable = new QState(stoppedState);
+    noSpawnsAvailable->setObjectName("noSpawnsAvailable");
+    noSpawnsAvailable->assignProperty(addTankAction, "enabled", false);
+
+    spawnsAvailable->addTransition(this, SIGNAL(mapFull()), noSpawnsAvailable);
+
+    QHistoryState *hs = new QHistoryState(stoppedState);
+    hs->setDefaultState(spawnsAvailable);
+
+    stoppedState->setInitialState(hs);
+
+//! [0]
+    m_runningState = new QState(QState::ParallelStates, m_machine->rootState());
+//! [0]
+    m_runningState->setObjectName("runningState");
+    m_runningState->assignProperty(addTankAction, "enabled", false);
+    m_runningState->assignProperty(runGameAction, "enabled", false);
+    m_runningState->assignProperty(stopGameAction, "enabled", true);
+        
+    stoppedState->addTransition(runGameAction, SIGNAL(triggered()), m_runningState);
+    m_runningState->addTransition(stopGameAction, SIGNAL(triggered()), stoppedState);
+
+    QTimer *timer = new QTimer(this);
+    timer->setInterval(100);
+    connect(timer, SIGNAL(timeout()), this, SLOT(runStep()));
+    connect(m_runningState, SIGNAL(entered()), timer, SLOT(start()));    
+    connect(m_runningState, SIGNAL(exited()), timer, SLOT(stop()));
+
+    m_machine->start();
+    m_time.start();
+}   
+
+void MainWindow::runStep()
+{
+    if (!m_started) {
+        m_time.restart();
+        m_started = true;
+    } else {
+        int elapsed = m_time.elapsed();
+        if (elapsed > 0) {
+            m_time.restart();
+            qreal elapsedSecs = elapsed / 1000.0;
+            QList<QGraphicsItem *> items = m_scene->items();
+            foreach (QGraphicsItem *item, items) {
+                if (GameItem *gameItem = qgraphicsitem_cast<GameItem *>(item))
+                    gameItem->idle(elapsedSecs);
+            }
+        }
+    }
+}
+
+void MainWindow::addRocket()
+{
+    TankItem *tankItem = qobject_cast<TankItem *>(sender());
+    if (tankItem != 0) {
+        RocketItem *rocketItem = new RocketItem;
+
+        QPointF s = tankItem->mapToScene(QPointF(tankItem->boundingRect().right() + 10.0, 
+                                                 tankItem->boundingRect().center().y()));
+        rocketItem->setPos(s);
+        rocketItem->setDirection(tankItem->direction());
+        m_scene->addItem(rocketItem);
+    }
+}
+
+void MainWindow::addTank()
+{
+    Q_ASSERT(!m_spawns.isEmpty());
+
+    QDir pluginsDir(qApp->applicationDirPath());
+#if defined(Q_OS_WIN)
+    if (pluginsDir.dirName().toLower() == "debug" || pluginsDir.dirName().toLower() == "release")
+        pluginsDir.cdUp();
+#elif defined(Q_OS_MAC)
+    if (pluginsDir.dirName() == "MacOS") {
+        pluginsDir.cdUp();
+        pluginsDir.cdUp();
+        pluginsDir.cdUp();
+    }
+#endif
+
+    pluginsDir.cd("plugins");
+
+    QStringList itemNames;
+    QList<Plugin *> items;
+    foreach (QString fileName, pluginsDir.entryList(QDir::Files)) {
+        QPluginLoader loader(pluginsDir.absoluteFilePath(fileName));
+        QObject *possiblePlugin = loader.instance();
+        if (Plugin *plugin = qobject_cast<Plugin *>(possiblePlugin)) {
+            QString objectName = possiblePlugin->objectName();
+            if (objectName.isEmpty())
+                objectName = fileName;
+
+            itemNames.append(objectName);
+            items.append(plugin);
+        }
+    }
+
+    if (items.isEmpty()) {
+        QMessageBox::information(this, "No tank types found", "Please build the errorstateplugins directory");
+        return;
+    }
+
+    bool ok;
+//! [1]
+    QString selectedName = QInputDialog::getItem(this, "Select a tank type", "Tank types", 
+        itemNames, 0, false, &ok);
+//! [1]
+    
+    if (ok && !selectedName.isEmpty()) {
+        int idx = itemNames.indexOf(selectedName);
+        if (Plugin *plugin = idx >= 0 ? items.at(idx) : 0) {
+            TankItem *tankItem = m_spawns.takeLast();
+            m_scene->addItem(tankItem);
+            connect(tankItem, SIGNAL(cannonFired()), this, SLOT(addRocket()));
+            if (m_spawns.isEmpty())
+                emit mapFull();
+            
+            QState *region = new QState(m_runningState);
+//! [2]
+            QState *pluginState = plugin->create(region, tankItem);
+//! [2]
+            region->setInitialState(pluginState);
+
+
+            // If the plugin has an error it is disabled
+            QState *errorState = new QState(region);
+            errorState->assignProperty(tankItem, "enabled", false);
+            pluginState->setErrorState(errorState);
+        }
+    }
+}
+
diff --git a/examples/statemachine/tankgame/mainwindow.h b/examples/statemachine/tankgame/mainwindow.h
new file mode 100644
index 0000000..622dabe
--- /dev/null
+++ b/examples/statemachine/tankgame/mainwindow.h
@@ -0,0 +1,46 @@
+#ifndef MAINWINDOW_H
+#define MAINWINDOW_H
+
+#include <QMainWindow>
+#include <QTime>
+
+class QGraphicsScene;
+class QStateMachine;
+class QState;
+class TankItem;
+class MainWindow: public QMainWindow
+{
+    Q_OBJECT
+    Q_PROPERTY(bool started READ started WRITE setStarted)
+public:
+    MainWindow(QWidget *parent = 0);
+    ~MainWindow();
+
+    void setStarted(bool b) { m_started = b; }
+    bool started() const { return m_started; }
+
+public slots:
+    void addTank();
+    void addRocket();
+    void runStep();
+
+signals:
+    void mapFull();
+
+private:
+    void init();
+    void addWall(const QRectF &wall);
+
+    QGraphicsScene *m_scene;
+    
+    QStateMachine *m_machine;
+    QState *m_runningState;
+
+    QList<TankItem *> m_spawns;
+    QTime m_time;
+    
+    bool m_started : 1;
+};
+
+#endif
+
diff --git a/examples/statemachine/tankgame/plugin.h b/examples/statemachine/tankgame/plugin.h
new file mode 100644
index 0000000..2b48d43
--- /dev/null
+++ b/examples/statemachine/tankgame/plugin.h
@@ -0,0 +1,17 @@
+#ifndef PLUGIN_H
+#define PLUGIN_H
+
+#include <QtPlugin>
+
+class QState;
+class Plugin
+{
+public:
+    virtual ~Plugin() {}
+
+    virtual QState *create(QState *parentState, QObject *tank) = 0;
+};
+
+Q_DECLARE_INTERFACE(Plugin, "TankPlugin")
+
+#endif
diff --git a/examples/statemachine/tankgame/rocketitem.cpp b/examples/statemachine/tankgame/rocketitem.cpp
new file mode 100644
index 0000000..c324980
--- /dev/null
+++ b/examples/statemachine/tankgame/rocketitem.cpp
@@ -0,0 +1,60 @@
+#include "rocketitem.h"
+#include "tankitem.h"
+
+#include <QPainter>
+#include <QGraphicsScene>
+
+#include <math.h>
+
+#ifndef M_PI
+#define M_PI 3.14159265358979323846
+#endif
+
+RocketItem::RocketItem(QObject *parent)
+    : GameItem(parent), m_direction(0.0), m_distance(300.0)
+{
+}
+
+QRectF RocketItem::boundingRect() const
+{
+    return QRectF(-1.0, -1.0, 2.0, 2.0);
+}
+
+void RocketItem::paint(QPainter *painter, const QStyleOptionGraphicsItem *, QWidget *)
+{
+    painter->setBrush(Qt::black);
+    painter->drawEllipse(boundingRect());
+}
+
+void RocketItem::idle(qreal elapsed)
+{
+    qreal dist = elapsed * speed();
+
+    m_distance -= dist;
+    if (m_distance < 0.0) {
+        scene()->removeItem(this);
+        delete this;
+        return;
+    }
+
+    qreal a = m_direction * M_PI / 180.0;
+
+    qreal yd = dist * sin(a);
+    qreal xd = dist * sin(M_PI / 2.0 - a);
+
+    QPointF requestedPosition = pos() + QPointF(xd, yd);
+    QGraphicsItem *collidedItem = 0;
+    QPointF nextPosition = tryMove(requestedPosition, 0, &collidedItem);
+    if (requestedPosition == nextPosition) {
+        setPos(nextPosition);
+    } else {
+        if (GameItem *gameItem = qgraphicsitem_cast<GameItem *>(collidedItem)) {
+            TankItem *tankItem = qobject_cast<TankItem *>(gameItem);
+            if (tankItem != 0)
+                tankItem->hitByRocket();
+        }
+        
+        scene()->removeItem(this);
+        delete this;
+    }
+}
diff --git a/examples/statemachine/tankgame/rocketitem.h b/examples/statemachine/tankgame/rocketitem.h
new file mode 100644
index 0000000..189a1dd
--- /dev/null
+++ b/examples/statemachine/tankgame/rocketitem.h
@@ -0,0 +1,26 @@
+#ifndef ROCKETITEM_H
+#define ROCKETITEM_H
+
+#include "gameitem.h"
+
+class RocketItem: public GameItem
+{
+    Q_OBJECT
+public:
+    RocketItem(QObject *parent = 0);
+
+    virtual void idle(qreal elapsed);
+    qreal speed() const { return 100.0; }
+    void setDirection(qreal direction) { m_direction = direction; }
+    
+protected:
+    virtual void paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget);
+    QRectF boundingRect() const;
+
+private:
+    qreal m_direction;
+    qreal m_distance;
+};
+
+
+#endif
diff --git a/examples/statemachine/tankgame/tankgame.pro b/examples/statemachine/tankgame/tankgame.pro
new file mode 100644
index 0000000..f7b0760
--- /dev/null
+++ b/examples/statemachine/tankgame/tankgame.pro
@@ -0,0 +1,13 @@
+######################################################################
+# Automatically generated by qmake (2.01a) on 22. apr 14:11:33 2009
+######################################################################
+
+TEMPLATE = app
+TARGET = 
+DEPENDPATH += .
+INCLUDEPATH += C:/dev/kinetic/examples/statemachine/tankgame/. .
+
+# Input
+HEADERS += mainwindow.h plugin.h tankitem.h rocketitem.h gameitem.h
+SOURCES += main.cpp mainwindow.cpp tankitem.cpp rocketitem.cpp gameitem.cpp
+CONFIG += console
diff --git a/examples/statemachine/tankgame/tankitem.cpp b/examples/statemachine/tankgame/tankitem.cpp
new file mode 100644
index 0000000..5506a7e
--- /dev/null
+++ b/examples/statemachine/tankgame/tankitem.cpp
@@ -0,0 +1,262 @@
+#include "tankitem.h"
+
+#include <QPainter>
+#include <QGraphicsScene>
+#include <QDebug>
+
+#include <math.h>
+
+#ifndef M_PI
+#define M_PI 3.14159265358979323846
+#endif
+
+class Action
+{
+public:
+    Action(TankItem *item) : m_item(item)
+    {
+    }
+
+    TankItem *item() const { return m_item; }
+    void setItem(TankItem *item) { m_item = item; }
+
+    virtual bool apply(qreal timeDelta) = 0;
+
+private:
+    TankItem *m_item;
+};
+
+class MoveAction: public Action
+{
+public:
+    MoveAction(TankItem *item, qreal distance)
+        : Action(item), m_distance(distance)
+    {
+        m_reverse = m_distance < 0.0;
+    }
+
+    bool apply(qreal timeDelta) 
+    {
+        qreal dist = timeDelta * item()->speed() * (m_reverse ? -1.0 : 1.0);
+
+        bool done = false;        
+        if (qAbs(m_distance) < qAbs(dist)) {            
+            done = true;
+            dist = m_distance;
+        } 
+        m_distance -= dist;
+
+        qreal a = item()->direction() * M_PI / 180.0;
+
+        qreal yd = dist * sin(a);
+        qreal xd = dist * sin(M_PI / 2.0 - a);
+
+        item()->setPos(item()->pos() + QPointF(xd, yd));
+        return !done;
+    }
+
+private:
+    qreal m_distance;
+    bool m_reverse;
+};
+
+class TurnAction: public Action
+{
+public:
+    TurnAction(TankItem *item, qreal distance)
+        : Action(item), m_distance(distance)
+    {
+        m_reverse = m_distance < 0.0;
+    }
+
+    bool apply(qreal timeDelta) 
+    {
+        qreal dist = timeDelta * item()->angularSpeed() * (m_reverse ? -1.0 : 1.0);
+        bool done = false;        
+        if (qAbs(m_distance) < qAbs(dist)) {
+            done = true;
+            dist = m_distance;
+        } 
+        m_distance -= dist;
+
+        item()->setDirection(item()->direction() + dist);
+        return !done;
+    }
+
+private:
+    qreal m_distance;
+    bool m_reverse;
+};
+
+TankItem::TankItem(QObject *parent) 
+    : GameItem(parent), m_currentAction(0), m_currentDirection(0.0), m_enabled(true)
+{
+    connect(this, SIGNAL(cannonFired()), this, SIGNAL(actionCompleted()));
+}
+
+void TankItem::idle(qreal elapsed)
+{
+    if (m_enabled) {
+        if (m_currentAction != 0) {
+            if (!m_currentAction->apply(elapsed)) {
+                setAction(0);
+                emit actionCompleted();
+            }
+
+            QGraphicsItem *item = 0;
+            qreal distance = distanceToObstacle(&item);
+            if (TankItem *tankItem = qgraphicsitem_cast<TankItem *>(item))
+                emit tankSpotted(tankItem->direction(), distance);        
+        }
+    }
+}
+
+void TankItem::hitByRocket()
+{
+    deleteLater();
+}
+
+void TankItem::setAction(Action *newAction)
+{
+    if (m_currentAction != 0) 
+        delete m_currentAction;
+
+    m_currentAction = newAction;
+}
+
+void TankItem::fireCannon()
+{
+    emit cannonFired();
+}
+
+void TankItem::moveForwards(qreal length)
+{
+    setAction(new MoveAction(this, length));
+}
+
+void TankItem::moveBackwards(qreal length)
+{
+    setAction(new MoveAction(this, -length));
+}
+
+void TankItem::turn(qreal degrees)
+{
+    setAction(new TurnAction(this, degrees));
+}
+
+void TankItem::turnTo(qreal degrees)
+{
+    setAction(new TurnAction(this, degrees - direction()));
+}
+
+void TankItem::stop()
+{
+    setAction(0);
+}
+
+QVariant TankItem::itemChange(QGraphicsItem::GraphicsItemChange change, const QVariant &value)
+{
+    if (change == ItemPositionChange && scene()) {
+        QPointF requestedPosition = value.toPointF();
+        QLineF collidedLine;
+        QPointF nextPoint = tryMove(requestedPosition, &collidedLine);
+        if (nextPoint != requestedPosition)
+            emit collision(collidedLine);
+        return nextPoint;
+    } else {
+        return QGraphicsItem::itemChange(change, value);
+    }
+}
+
+
+void TankItem::paint(QPainter *painter, const QStyleOptionGraphicsItem *, QWidget *)
+{
+    QRectF brect = boundingRect();
+
+    painter->setBrush(m_color);
+    painter->setPen(Qt::black);
+
+    // body
+    painter->drawRect(brect.adjusted(0.0, 4.0, -2.0, -4.0));
+
+    // cannon
+    QRectF cannonBase = brect.adjusted(10.0, 6.0, -12.0, -6.0);
+    painter->drawEllipse(cannonBase);
+
+    painter->drawRect(QRectF(QPointF(cannonBase.center().x(), cannonBase.center().y() - 2.0), 
+                             QPointF(brect.right(), cannonBase.center().y() + 2.0)));
+    
+    // left track
+    painter->setBrush(QBrush(Qt::black, Qt::VerPattern));
+    QRectF leftTrackRect = QRectF(brect.topLeft(), QPointF(brect.right() - 2.0, brect.top() + 4.0));
+    painter->fillRect(leftTrackRect, Qt::darkYellow);
+    painter->drawRect(leftTrackRect);
+
+    // right track
+    QRectF rightTrackRect = QRectF(QPointF(brect.left(), brect.bottom() - 4.0),
+                                   QPointF(brect.right() - 2.0, brect.bottom()));
+    painter->fillRect(rightTrackRect, Qt::darkYellow);
+    painter->drawRect(rightTrackRect);
+
+    if (!m_enabled) {
+        painter->setPen(QPen(Qt::red, 5));
+
+        painter->drawEllipse(brect);
+
+        QPainterPath path;
+        path.addEllipse(brect);
+        painter->setClipPath(path);
+        painter->drawLine(brect.topRight(), brect.bottomLeft());
+    }
+}
+
+QRectF TankItem::boundingRect() const
+{
+    return QRectF(-20.0, -10.0, 40.0, 20.0);
+}
+
+qreal TankItem::direction() const
+{
+    return m_currentDirection;
+}
+
+void TankItem::setDirection(qreal newDirection)
+{
+    int fullRotations = int(newDirection) / 360;    
+    newDirection -= fullRotations * 360.0;
+
+    qreal diff = newDirection - m_currentDirection;
+    m_currentDirection = newDirection;
+    rotate(diff);
+}
+
+qreal TankItem::distanceToObstacle(QGraphicsItem **obstacle) const
+{
+    qreal dist = sqrt(pow(scene()->sceneRect().width(), 2) + pow(scene()->sceneRect().height(), 2));
+
+    qreal a = m_currentDirection * M_PI / 180.0;
+
+    qreal yd = dist * sin(a);
+    qreal xd = dist * sin(M_PI / 2.0 - a);
+
+    QPointF requestedPosition = pos() + QPointF(xd, yd);
+    QGraphicsItem *collidedItem = 0;
+    QPointF nextPosition = tryMove(requestedPosition, 0, &collidedItem);
+    if (collidedItem != 0) {
+        if (obstacle != 0)
+            *obstacle = collidedItem;        
+        
+        QPointF d = nextPosition - pos();
+        return sqrt(pow(d.x(), 2) + pow(d.y(), 2));
+    } else {
+        return 0.0;
+    }
+}
+
+qreal TankItem::distanceToObstacle() const
+{
+    return distanceToObstacle(0);
+}
+
+
+
diff --git a/examples/statemachine/tankgame/tankitem.h b/examples/statemachine/tankgame/tankitem.h
new file mode 100644
index 0000000..66f05aa
--- /dev/null
+++ b/examples/statemachine/tankgame/tankitem.h
@@ -0,0 +1,67 @@
+#ifndef TANKITEM_H
+#define TANKITEM_H
+
+#include "gameitem.h"
+
+#include <QColor>
+
+class Action;
+class TankItem: public GameItem
+{
+    Q_OBJECT
+    Q_PROPERTY(bool enabled READ enabled WRITE setEnabled)
+    Q_PROPERTY(qreal direction READ direction WRITE turnTo)
+    Q_PROPERTY(qreal distanceToObstacle READ distanceToObstacle)
+public:   
+    TankItem(QObject *parent = 0);
+        
+    void setColor(const QColor &color) { m_color = color; }
+    QColor color() const { return m_color; }
+
+    void idle(qreal elapsed);
+    void setDirection(qreal newDirection);
+
+    qreal speed() const { return 90.0; }
+    qreal angularSpeed() const { return 90.0; }
+
+    QRectF boundingRect() const;
+
+    void hitByRocket();
+
+    void setEnabled(bool b) { m_enabled = b; }
+    bool enabled() const { return m_enabled; }
+
+    qreal direction() const;
+    qreal distanceToObstacle() const;
+    qreal distanceToObstacle(QGraphicsItem **item) const;
+
+//! [0]
+signals:
+    void tankSpotted(qreal direction, qreal distance);
+    void collision(const QLineF &collidedLine);
+    void actionCompleted();
+    void cannonFired();
+
+public slots:
+    void moveForwards(qreal length = 10.0);
+    void moveBackwards(qreal length = 10.0);
+    void turn(qreal degrees = 30.0);
+    void turnTo(qreal degrees = 0.0);
+    void stop();
+    void fireCannon();
+//! [0]
+
+protected:
+    virtual void paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget);    
+    QVariant itemChange(QGraphicsItem::GraphicsItemChange change, const QVariant &value);
+
+private:
+    void setAction(Action *newAction);
+
+    Action *m_currentAction;
+    qreal m_currentDirection;
+    QColor m_color;
+    bool m_enabled;
+};
+
+#endif