states.cpp Example File
demos/sub-attaq/states.cpp

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 //Own
 #include "states.h"
 #include "graphicsscene.h"
 #include "boat.h"
 #include "submarine.h"
 #include "torpedo.h"
 #include "animationmanager.h"
 #include "progressitem.h"
 #include "textinformationitem.h"

 //Qt
 #include <QtGui/QMessageBox>
 #include <QtGui/QGraphicsView>
 #include <QtCore/QStateMachine>
 #include <QtGui/QKeyEventTransition>
 #include <QtCore/QFinalState>

 PlayState::PlayState(GraphicsScene *scene, QState *parent)
     : QState(parent),
     scene(scene),
     machine(0),
     currentLevel(0),
     score(0)
 {
 }

 PlayState::~PlayState()
 {
     delete machine;
 }

 void PlayState::onEntry(QEvent *)
 {
     //We are now playing?
     if (machine) {
         machine->stop();
         //we hide the information
         scene->textInformationItem->hide();
         scene->clearScene();
         currentLevel = 0;
         score = 0;
         delete machine;
     }

     machine = new QStateMachine;

     //This state is when player is playing
     LevelState *levelState = new LevelState(scene, this, machine);

     //This state is when the player is actually playing but the game is not paused
     QState *playingState = new QState(levelState);
     levelState->setInitialState(playingState);

     //This state is when the game is paused
     PauseState *pauseState = new PauseState(scene, levelState);

     //We have one view, it receive the key press event
     QKeyEventTransition *pressPplay = new QKeyEventTransition(scene->views().at(0), QEvent::KeyPress, Qt::Key_P);
     pressPplay->setTargetState(pauseState);
     QKeyEventTransition *pressPpause = new QKeyEventTransition(scene->views().at(0), QEvent::KeyPress, Qt::Key_P);
     pressPpause->setTargetState(playingState);

     //Pause "P" is triggered, the player pause the game
     playingState->addTransition(pressPplay);

     //To get back playing when the game has been paused
     pauseState->addTransition(pressPpause);

     //This state is when player have lost
     LostState *lostState = new LostState(scene, this, machine);

     //This state is when player have won
     WinState *winState = new WinState(scene, this, machine);

     //The boat has been destroyed then the game is finished
     levelState->addTransition(scene->boat, SIGNAL(boatExecutionFinished()),lostState);

     //This transition check if we won or not
     WinTransition *winTransition = new WinTransition(scene, this, winState);

     //The boat has been destroyed then the game is finished
     levelState->addTransition(winTransition);

     //This state is an animation when the score changed
     UpdateScoreState *scoreState = new UpdateScoreState(this, levelState);

     //This transition update the score when a submarine die
     UpdateScoreTransition *scoreTransition = new UpdateScoreTransition(scene, this, levelState);
     scoreTransition->setTargetState(scoreState);

     //The boat has been destroyed then the game is finished
     playingState->addTransition(scoreTransition);

     //We go back to play state
     scoreState->addTransition(playingState);

     //We start playing!!!
     machine->setInitialState(levelState);

     //Final state
     QFinalState *final = new QFinalState(machine);

     //This transition is triggered when the player press space after completing a level
     CustomSpaceTransition *spaceTransition = new CustomSpaceTransition(scene->views().at(0), this, QEvent::KeyPress, Qt::Key_Space);
     spaceTransition->setTargetState(levelState);
     winState->addTransition(spaceTransition);

     //We lost we should reach the final state
     lostState->addTransition(lostState, SIGNAL(finished()), final);

     machine->start();
 }

 LevelState::LevelState(GraphicsScene *scene, PlayState *game, QState *parent) : QState(parent), scene(scene), game(game)
 {
 }
 void LevelState::onEntry(QEvent *)
 {
     initializeLevel();
 }

 void LevelState::initializeLevel()
 {
     //we re-init the boat
     scene->boat->setPos(scene->width()/2, scene->sealLevel() - scene->boat->size().height());
     scene->boat->setCurrentSpeed(0);
     scene->boat->setCurrentDirection(Boat::None);
     scene->boat->setBombsLaunched(0);
     scene->boat->show();
     scene->setFocusItem(scene->boat, Qt::OtherFocusReason);
     scene->boat->run();

     scene->progressItem->setScore(game->score);
     scene->progressItem->setLevel(game->currentLevel + 1);

     GraphicsScene::LevelDescription currentLevelDescription = scene->levelsData.value(game->currentLevel);

     for (int i = 0; i < currentLevelDescription.submarines.size(); ++i ) {

         QPair<int,int> subContent = currentLevelDescription.submarines.at(i);
         GraphicsScene::SubmarineDescription submarineDesc = scene->submarinesData.at(subContent.first);

         for (int j = 0; j < subContent.second; ++j ) {
             SubMarine *sub = new SubMarine(submarineDesc.type, submarineDesc.name, submarineDesc.points);
             scene->addItem(sub);
             int random = (qrand() % 15 + 1);
             qreal x = random == 13 || random == 5 ? 0 : scene->width() - sub->size().width();
             qreal y = scene->height() -(qrand() % 150 + 1) - sub->size().height();
             sub->setPos(x,y);
             sub->setCurrentDirection(x == 0 ? SubMarine::Right : SubMarine::Left);
             sub->setCurrentSpeed(qrand() % 3 + 1);
         }
     }
 }

 /** Pause State */
 PauseState::PauseState(GraphicsScene *scene, QState *parent) : QState(parent),scene(scene)
 {
 }
 void PauseState::onEntry(QEvent *)
 {
     AnimationManager::self()->pauseAll();
     scene->boat->setEnabled(false);
 }
 void PauseState::onExit(QEvent *)
 {
     AnimationManager::self()->resumeAll();
     scene->boat->setEnabled(true);
     scene->boat->setFocus();
 }

 /** Lost State */
 LostState::LostState(GraphicsScene *scene, PlayState *game, QState *parent) : QState(parent), scene(scene), game(game)
 {
 }

 void LostState::onEntry(QEvent *)
 {
     //The message to display
     QString message = QString("You lose on level %1. Your score is %2.").arg(game->currentLevel+1).arg(game->score);

     //We set the level back to 0
     game->currentLevel = 0;

     //We set the score back to 0
     game->score = 0;

     //We clear the scene
     scene->clearScene();

     //We inform the player
     scene->textInformationItem->setMessage(message);
     scene->textInformationItem->show();
 }

 void LostState::onExit(QEvent *)
 {
     //we hide the information
     scene->textInformationItem->hide();
 }

 /** Win State */
 WinState::WinState(GraphicsScene *scene, PlayState *game, QState *parent) : QState(parent), scene(scene), game(game)
 {
 }

 void WinState::onEntry(QEvent *)
 {
     //We clear the scene
     scene->clearScene();

     QString message;
     if (scene->levelsData.size() - 1 != game->currentLevel) {
         message = QString("You win the level %1. Your score is %2.\nPress Space to continue.").arg(game->currentLevel+1).arg(game->score);
         //We increment the level number
         game->currentLevel++;
     } else {
         message = QString("You finish the game on level %1. Your score is %2.").arg(game->currentLevel+1).arg(game->score);
         //We set the level back to 0
         game->currentLevel = 0;
         //We set the score back to 0
         game->score = 0;
     }

     //We inform the player
     scene->textInformationItem->setMessage(message);
     scene->textInformationItem->show();
 }

 void WinState::onExit(QEvent *)
 {
     //we hide the information
     scene->textInformationItem->hide();
 }

 /** UpdateScore State */
 UpdateScoreState::UpdateScoreState(PlayState *g, QState *parent) : QState(parent), game(g)
 {
 }

 /** Win transition */
 UpdateScoreTransition::UpdateScoreTransition(GraphicsScene *scene, PlayState *game, QAbstractState *target)
     : QSignalTransition(scene,SIGNAL(subMarineDestroyed(int))),
     game(game), scene(scene)
 {
     setTargetState(target);
 }

 bool UpdateScoreTransition::eventTest(QEvent *event)
 {
     if (!QSignalTransition::eventTest(event))
         return false;
     QStateMachine::SignalEvent *se = static_cast<QStateMachine::SignalEvent*>(event);
     game->score += se->arguments().at(0).toInt();
     scene->progressItem->setScore(game->score);
     return true;
 }

 /** Win transition */
 WinTransition::WinTransition(GraphicsScene *scene, PlayState *game, QAbstractState *target)
     : QSignalTransition(scene,SIGNAL(allSubMarineDestroyed(int))),
     game(game), scene(scene)
 {
     setTargetState(target);
 }

 bool WinTransition::eventTest(QEvent *event)
 {
     if (!QSignalTransition::eventTest(event))
         return false;
     QStateMachine::SignalEvent *se = static_cast<QStateMachine::SignalEvent*>(event);
     game->score += se->arguments().at(0).toInt();
     scene->progressItem->setScore(game->score);
     return true;
 }

 /** Space transition */
 CustomSpaceTransition::CustomSpaceTransition(QWidget *widget, PlayState *game, QEvent::Type type, int key)
     :   QKeyEventTransition(widget, type, key),
         game(game)
 {
 }

 bool CustomSpaceTransition::eventTest(QEvent *event)
 {
     if (!QKeyEventTransition::eventTest(event))
         return false;
     return (game->currentLevel != 0);
 }