Qt Reference Documentation

# 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);
     }