Object-Oriented Programming in Pacman-Typescript

This outline explores how the codebase utilizes object-oriented principles. The primary focus is on classes, inheritance, and polymorphism.

Classes

Purpose: Classes are the building blocks for creating reusable objects. They encapsulate data (properties) and behavior (methods) to represent entities in the game.

Example:

• Game Class:
  • game.ts src/game.ts
  • Properties:
    • canvas: Reference to the HTML canvas element.
    • ctx: Canvas 2D drawing context.
    • pacman: Reference to the Pacman instance.
    • ghosts: Array of Ghost instances.
    • pellets: Array of Pellet instances.
    • powerPellets: Array of PowerPellet instances.
    • score: Current game score.
    • lives: Number of remaining lives.
    • level: Current game level.
  • Methods:
    • start(): Initializes the game.
    • update(): Updates game state and handles logic.
    • draw(): Renders game elements on the canvas.
    • reset(): Resets the game to its initial state.

Example (Modified):

class Game {
            // Properties
            canvas: HTMLCanvasElement;
            ctx: CanvasRenderingContext2D;
            pacman: Pacman;
            ghosts: Ghost[];
            pellets: Pellet[];
            powerPellets: PowerPellet[];
            score: number;
            lives: number;
            level: number;
          
            // Methods
            start() {
              // Initialize game state
            }
          
            update() {
              // Update game state and logic
            }
          
            draw() {
              // Render game elements on the canvas
            }
          
            reset() {
              // Reset the game to its initial state
            }
          }
          
          // Example Usage
          const game = new Game();
          game.start();
          

Inheritance

Purpose: Inheritance allows you to create new classes based on existing ones, inheriting their properties and methods. This promotes code reuse and organization.

Example:

• Ghost Class: src/ghost.ts
• Blinky Class: src/ghost.ts
• Pinky Class: src/ghost.ts
• Inky Class: src/ghost.ts
• Clyde Class: src/ghost.ts

Example (Modified):

class Ghost {
            // Common ghost properties and methods
          }
          
          class Blinky extends Ghost {
            // Blinky-specific properties and methods
          }
          
          class Pinky extends Ghost {
            // Pinky-specific properties and methods
          }
          
          // ... (Inky, Clyde)
          
          // Example Usage
          const blinky = new Blinky();
          const pinky = new Pinky();
          
          // Access inherited properties and methods
          blinky.position = { x: 100, y: 100 };
          pinky.move(); 
          

Polymorphism

Purpose: Polymorphism allows objects of different classes to be treated as objects of a common type. This enables code to work with various objects without knowing their specific type.

Example:

• Ghost Class: Provides common methods like move() and draw().
• Blinky, Pinky, Inky, and Clyde Classes: Implement the move() method with specific behaviors for each ghost type.

Example (Modified):

class Ghost {
            // ...
            move() {
              // General movement logic
            }
            // ...
          }
          
          class Blinky extends Ghost {
            move() {
              // Blinky-specific movement logic
            }
          }
          
          // ... (Pinky, Inky, Clyde)
          
          // Example Usage
          const ghosts: Ghost[] = [new Blinky(), new Pinky(), new Inky(), new Clyde()];
          
          // Loop through all ghosts and call the move() method
          for (const ghost of ghosts) {
            ghost.move(); // Polymorphic call - appropriate move() implementation is executed based on the ghost's type
          }
          

This outline provides a foundation for understanding the object-oriented principles employed in the pacman-typescript codebase. It illustrates how classes, inheritance, and polymorphism contribute to its organization and code reuse.