1. Understanding Phaser.js and Game Basics
Before starting, it’s important to understand what Phaser.js is. Phaser is an open-source HTML5 game framework designed for building desktop and mobile browser games. It simplifies complex game functions like animation, physics, asset management, and collision detection.
The Snake Game is a perfect beginner project because it requires basic movement control, collision logic, score tracking, and food generation. With Phaser, all these elements become manageable and intuitive.
Core Mechanics of the Snake Game
The snake moves continuously in a chosen direction.
The player can change the direction using keyboard arrows.
The snake eats food, grows longer, and increases the score.
The game ends when the snake collides with itself or the wall.
These concepts can be implemented efficiently using Phaser’s features such as scenes, physics, and timers.
2. Setting Up the Phaser Environment
The first step is to set up the development environment. You’ll need:
A basic HTML file to load Phaser.
A JavaScript file to write the game logic.
Here’s a simple structure:
index.html
js/
└── game.js
assets/
└── (optional images or sounds)
In your HTML file, include the Phaser library using a script tag and link your main game script:
<script src="https://cdn.jsdelivr.net/npm/phaser@3/dist/phaser.js"></script>
<script src="js/game.js"></script>
Now, you have a Phaser environment ready to run your game logic.
3. Initializing the Game Configuration
Phaser games start with a configuration object that defines properties like screen size, physics, and the game scene.
Example:
const config = {
type: Phaser.AUTO,
width: 800,
height: 600,
backgroundColor: '#000000',
scene: {
preload: preload,
create: create,
update: update
}
};
const game = new Phaser.Game(config);
This code initializes a Phaser game with a black background. The functions preload, create, and update will control your game’s flow.
4. Preloading Game Assets
In many games, you need assets such as images or sounds. For a simple snake game, we can use plain colors or basic shapes generated within Phaser, so no external assets are necessary.
If you want to use custom graphics (like a fruit image), load it here:
function preload() {
this.load.image('food', 'assets/food.png');
}
Otherwise, you can skip this step for a minimalist design.
5. Creating the Snake and Food
The snake can be represented as an array of blocks, and the food as a single block randomly placed on the grid.
In the create() function:
let snake = [];
let food;
let direction = 'RIGHT';
let newDirection = 'RIGHT';
let score = 0;
function create() {
const gridSize = 20;
const startX = 8;
const startY = 8;
for (let i = 0; i < 5; i++) {
snake.push(this.add.rectangle((startX - i) * gridSize, startY * gridSize, gridSize, gridSize, 0x00ff00));
}
food = this.add.rectangle(
Phaser.Math.Between(0, 39) * gridSize,
Phaser.Math.Between(0, 29) * gridSize,
gridSize,
gridSize,
0xff0000
);
this.input.keyboard.on('keydown', handleInput, this);
this.time.addEvent({
delay: 150,
loop: true,
callback: moveSnake,
callbackScope: this
});
}
Here’s what happens:
A snake of 5 blocks is created.
Food appears randomly on the screen.
Keyboard input controls movement.
The snake moves every 150 milliseconds.
6. Handling Player Input
The snake’s direction must change based on arrow keys, but it shouldn’t reverse directly into itself.
function handleInput(event) {
switch (event.keyCode) {
case 37: if (direction !== 'RIGHT') newDirection = 'LEFT'; break;
case 38: if (direction !== 'DOWN') newDirection = 'UP'; break;
case 39: if (direction !== 'LEFT') newDirection = 'RIGHT'; break;
case 40: if (direction !== 'UP') newDirection = 'DOWN'; break;
}
}
This ensures smoother, logical movement without instantly colliding with itself.
7. Moving the Snake
Movement involves shifting each segment’s position to the previous one, updating the head based on direction.
function moveSnake() {
direction = newDirection;
const head = snake[0];
const gridSize = 20;
const newX = head.x + (direction === 'LEFT' ? -gridSize : direction === 'RIGHT' ? gridSize : 0);
const newY = head.y + (direction === 'UP' ? -gridSize : direction === 'DOWN' ? gridSize : 0);
const newHead = this.add.rectangle(newX, newY, gridSize, gridSize, 0x00ff00);
snake.unshift(newHead);
if (newX === food.x && newY === food.y) {
food.setPosition(Phaser.Math.Between(0, 39) * gridSize, Phaser.Math.Between(0, 29) * gridSize);
score += 10;
} else {
const tail = snake.pop();
tail.destroy();
}
checkCollision(newHead);
}
This function:
Moves the head in the chosen direction.
Adds a new segment at the front.
Removes the tail unless food is eaten.
Updates the score when food is eaten.
8. Detecting Collisions
The snake can collide with walls or itself, ending the game. Add this function:
function checkCollision(head) {
if (head.x < 0 || head.x >= 800 || head.y < 0 || head.y >= 600) {
gameOver.call(this);
return;
}
for (let i = 1; i < snake.length; i++) {
if (head.x === snake[i].x && head.y === snake[i].y) {
gameOver.call(this);
return;
}
}
}
This checks:
Wall collision (edges of the game area).
Self-collision (overlapping body segments).
9. Creating a Game Over Scene
When the game ends, display a restart message or score.
function gameOver() {
this.scene.pause();
const style = { fontSize: '32px', fill: '#fff' };
this.add.text(200, 300, 'Game Over! Press F5 to Restart', style);
}
You can enhance this by adding a restart button or resetting the snake array.
10. Adding a Score Display
A visible score makes the game more engaging. Add this in the create() function:
scoreText = this.add.text(10, 10, 'Score: 0', { fontSize: '20px', fill: '#ffffff' });
Then, update it whenever food is eaten:
scoreText.setText('Score: ' + score);
11. Polishing and Enhancing Gameplay
Once the basic game works, you can add improvements:
Speed Increase: Make the game faster as the score increases.
Sound Effects: Play a sound when food is eaten or when the player loses.
Grid Background: Draw grid lines to make the layout clearer.
Start Menu: Let the player start or restart from a menu scene.
Example for speed increase:
if (score % 50 === 0 && moveSpeed > 50) {
moveSpeed -= 10;
}
This small addition gradually makes the game more challenging.
12. Understanding Phaser Scenes
Phaser games can use multiple scenes to manage different stages like menus, gameplay, and game over screens. For a more advanced version, create separate scenes:
MainMenuScene
GameScene
GameOverScene
This structure helps you manage transitions and game states more efficiently, which is useful for scaling your game.
13. Testing and Debugging the Game
Testing ensures smooth gameplay across devices and browsers.
Key steps include:
Checking keyboard input responsiveness.
Ensuring food never spawns on the snake.
Verifying collision detection accuracy.
Adjusting the game speed for balanced difficulty.
You can use browser developer tools to debug, track variable values, and monitor frame rates.
14. Exporting and Sharing Your Game
Once complete, your Snake Game can be easily hosted online since it’s built with HTML5 and JavaScript. You can:
Upload to your website.
Share via GitHub Pages or Netlify.
Integrate into a learning portfolio or personal project page.
Phaser.js games run seamlessly on browsers, making them lightweight and accessible to everyone.
15. Conclusion
Building a Classic Snake Game using Phaser.js is not only an enjoyable project but also a fantastic learning experience in game development. You learn essential skills such as managing game loops, handling user input, detecting collisions, and structuring game scenes.
Through this step-by-step guide, you can now create your own working version of the Snake game, customize it with your designs, and add features to make it uniquely yours. Once you understand the fundamentals, you can easily expand into more complex projects using Phaser.js — from platformers and shooters to puzzles and adventure games.
