Qt pacman

A pacman game made with Qt Creator.

Play with w, a, s, d keys.

Qt spec

This is developed on Qt 6.2.1. If you want to develop under Qt 6, you may need to uncomment some lines in Qt-pac-man.pro file.

Name: Qt 6.2.1 GCC 64bit
ABI: x86-linux-generic-elf-64bit
Source: /opt/Qt/6.2.1/gcc_64
mkspec: linux-g++

How to call pacman game API

You can take reference from mainwindow.cpp and mainwindow.h for detailed code. Assume that the following steps are implemented in a QMainWindow.

Step 1: declare objects and functions

• Add a QGraphicsView named graphicsView for displaying game. (In the source code, graphicsView is defined in mainwindow.ui.)
• Add a QLabel named score for displaying score.
• Add two QLabels named win_label and lose_label for displaying when game is over.
• Add a QTimer named score_timer for updating current score.
• Declare keyPressEvent override function.
• Declare update_score slot function.
• Include game.h.

#include <QMainWindow>
#include <QLabel>
#include <QKeyEvent>
#include <QTimer>
#include "game.h"

QT_BEGIN_NAMESPACE
namespace Ui { class MainWindow; }
QT_END_NAMESPACE

class MainWindow : public QMainWindow
{
    Q_OBJECT

public:
    MainWindow(QWidget *parent = nullptr);
    ~MainWindow();
    void keyPressEvent(QKeyEvent*) override;

private slots:
    void update_score();

private:
    Ui::MainWindow *ui;
    QLabel *score, *win_label, *lose_label;
    QTimer *score_timer;
    Game *game;
};

Step 2: initialize objects

Setup graphicsView in the constructor of MainWindow.

#include "mainwindow.h"
#include "ui_mainwindow.h"

MainWindow::MainWindow(QWidget *parent)
    : QMainWindow(parent)
    , ui(new Ui::MainWindow)
{
    ui->graphicsView->setStyleSheet("QGraphicsView {border: none;}");
    ui->graphicsView->setBackgroundBrush(Qt::black);
    ui->graphicsView->setFocusPolicy(Qt::NoFocus);

Set the geometry of graphicsView and game. Read game map from map.txt.

    int map_height = 20, map_width = 29;            // 20x29 game map
    int x = 50, y = 50;                             // coordinate in mainwindow
    int w = (map_width * GameObject::Width);        // width pixel
    int h = (map_height * GameObject::Width);       // height pixel
    ui->graphicsView->setGeometry(x, y, w, h);
    game = new Game(x, y, map_width, map_height, ":/game_objects/map_objects/map.txt");
    ui->graphicsView->setScene(game);

Initialize labels and the timer.

    score = new QLabel(this);
    win_label = new QLabel(this);
    lose_label = new QLabel(this);
    score_timer = new QTimer(this);
    // setup labels' properties here...

Start timer and game.

    score_timer->start(25);
    connect(score_timer, SIGNAL(timeout()), this , SLOT(update_score()));
    game->start();
}

Step 3: Implement update_score and keyPressEvent

Update score when score_timer ticks. If the pacman eats all points, game->stat will change to Game::Win. If a ghost catches the pacman, game->stat will change to Game::Lose. Stop timer and show win_label or lose_label when game is over.

void MainWindow::update_score()
{
    score->setText(QString::number(game->get_score()));
    if (game->stat == Game::Win) {
        win_label->show();
        score_timer->stop();
    } else if (game->stat == Game::Lose) {
        lose_label->show();
        score_timer->stop();
    }
}

Detect key press events from w, a, s, d keys and make pacman move.

void MainWindow::keyPressEvent(QKeyEvent *e)
{
    switch (e->key()) {
    case Qt::Key_W:
        game->pacman_next_direction(GameObject::Up);
        break;
    case Qt::Key_A:
        game->pacman_next_direction(GameObject::Left);
        break;
    case Qt::Key_S:
        game->pacman_next_direction(GameObject::Down);
        break;
    case Qt::Key_D:
        game->pacman_next_direction(GameObject::Right);
        break;
    }
}

Changeable game parameters

Here are some changeable macro in game.h.

#define BALL_SCORE       10     // score of balls
#define POWERBALL_SCORE  30     // score of powerballs
#define GHOST_SCORE      50     // score of ghosts
#define INTERVAL         10     // move interval of pacman
#define NORMAL_INTERVAL  10     // move interval of normal ghosts
#define PANNIC_INTERVAL  15     // move interval of pannic ghosts
#define RUNNING_INTERVAL 5      // move interval of running ghosts
#define PANNIC_TIME      1000   // interval number of pannic ghosts
#define FLASH_INTERVAL   200    // flash interval of powerballs

Here's a changeable array in game.cpp.

// interval number before ghosts going out the cage
int GHOST_RELEASE_TIME[] = {0, 200, 400, 600};