Build a Car Engine Game

Introduction

In this tutorial, we will build a simple car engine game using JavaScript and HTML5. The game will involve the player clicking on the screen to make the car accelerate, brake, and turn. We will also add some basic physics to make the car feel more realistic.

Getting Started

To get started, we will create a new HTML file and add the following code:

<!DOCTYPE html>
<html>
<head>
  <title>Car Engine Game</title>
</head>
<body>
  <canvas id="myCanvas" width="500" height="500"></canvas>

  <script>
    // Get the canvas element
    var canvas = document.getElementById('myCanvas');

    // Get the context of the canvas
    var ctx = canvas.getContext('2d');

    // Create a new car object
    var car = new Car();

    // Add an event listener for the keydown event
    document.addEventListener('keydown', function(e) {
      // Check if the left arrow key was pressed
      if (e.keyCode == 37) {
        // Move the car to the left
        car.moveLeft();
      }

      // Check if the right arrow key was pressed
      if (e.keyCode == 39) {
        // Move the car to the right
        car.moveRight();
      }

      // Check if the up arrow key was pressed
      if (e.keyCode == 38) {
        // Accelerate the car
        car.accelerate();
      }

      // Check if the down arrow key was pressed
      if (e.keyCode == 40) {
        // Brake the car
        car.brake();
      }
    });

    // Update the game loop
    function update() {
      // Clear the canvas
      ctx.clearRect(0, 0, canvas.width, canvas.height);

      // Update the car's position
      car.update();

      // Draw the car
      car.draw();

      // Request the next animation frame
      requestAnimationFrame(update);
    }

    // Start the game loop
    update();
  </script>
</body>
</html>

The Car Object

The Car object will contain all of the properties and methods that we need to control the car. We will define the Car object as follows:

function Car() {
  // The car's position
  this.x = 0;
  this.y = 0;

  // The car's velocity
  this.vx = 0;
  this.vy = 0;

  // The car's acceleration
  this.ax = 0;
  this.ay = 0;

  // The car's max speed
  this.maxSpeed = 10;

  // The car's friction
  this.friction = 0.1;

  // The car's rotation
  this.rotation = 0;

  // The car's rotation speed
  this.rotationSpeed = 3;

  // The car's image
  this.image = new Image();
  this.image.src = 'car.png';
}

The Car’s Methods

The Car object will have the following methods:

moveLeft(): This method moves the car to the left.
moveRight(): This method moves the car to the right.
accelerate(): This method accelerates the car.
brake(): This method brakes the car.
update(): This method updates the car’s position and velocity.
draw(): This method draws the car to the canvas.

The Game Loop

The game loop is the part of the game that updates the game state and draws the game to the screen. The game loop will run continuously until the player closes the game. We will define the game loop as follows:

function update() {
  // Clear the canvas
  ctx.clearRect(0, 0, canvas.width, canvas.height);

  // Update the car's position
  car.update();

  // Draw the car
  car.draw();

  // Request the next animation frame
  requestAnimationFrame(update);
}

Starting the Game

To start the game, we will call the update() method once the page has loaded. We will do this as follows:

window.onload = function() {
  update();
};

Conclusion

In this tutorial, we have built a simple car engine game using JavaScript and HTML5. We have covered the basics of game development, including creating a game object, adding physics, and implementing a game loop. We have also learned how to use requestAnimationFrame to animate the game. With this knowledge, you can now create your own car engine games or other types of games.