Creating a Phaser 3 Template – Part 3

In Part 1 and Part 2 of this tutorial, we continued building a Phaser project template that you can reuse and extend in any future project you work on. In the first two parts we:

In Part 3 of this tutorial, we are going to continue working on our template by:

You can download all of the files associated with the source code for Part 3  here.

Let’s get started!

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Global State

Now that we have a way for a player to enable and disable audio in our game, we will need a way to make these values available to the other scenes in our game. One way of doing this is by creating a global state that can keep track of these values, that way as they are updated each scene will be able to access these values.

However, instead of just making these variables global, we will create a new Model class that will be used for keep track of these values. In the src folder, create a new file called Model.js and add the following code to it:

export default class Model {
  constructor() {
    this._soundOn = true;
    this._musicOn = true;
    this._bgMusicPlaying = false;
  }

  set musicOn(value) {
    this._musicOn = value;
  }

  get musicOn() {
    return this._musicOn;
  }

  set soundOn(value) {
    this._soundOn = value;
  }

  get soundOn() {
    return this._soundOn;
  }

  set bgMusicPlaying(value) {
    this._bgMusicPlaying = value;
  }

  get bgMusicPlaying() {
    return this._bgMusicPlaying;
  }
}

Let’s review the code we just added:

Now that we have our new model class, we still need a way to make it accessible to all our Phaser Scenes, and we can do that by adding that model to our Phaser Game object. To do this, open index.js and add the following code below the super call in our constructor:

const model = new Model();
this.globals = { model };

Next, add the following line at the top of the file with our other imports:

import Model from './Model';

In the code above, we imported our new Model class and we created a new instance of our class. We then created a new property on our Phaser Game object called globals, we made that property an object, and then we added our new Model instance to that object.

By adding the model instance to a property on our Phaser Game Object, we are now able to access that model in our Scenes by calling `this.sys.game.globals.model`.

So, now that we have a way to track the global state of our game, let’s go back to the Options Scene and update the local state in that scene to use our global state. Open OptionsScene.js and in the create function, replace the following lines:

this.musicOn = true;
this.soundOn = true;

with the following line:

this.model = this.sys.game.globals.model;

Then, update the this.musicOn = !this.musicOn; line to be:

this.model.musicOn = !this.model.musicOn;

Next, update the this.soundOn = !this.soundOn; line to be:

this.model.soundOn = !this.model.soundOn;

Then, at the bottom of the create function, add the following line:

this.updateAudio();

Finally, in the updateAudio function, update the this.musicOn === false and this.soundOn === false lines to be: this.model.musicOn === false and this.model.soundOn === false.

Now, if you save you your code changes and when your game refreshes you can test our new global state. If you click on one of the UI elements to disable it, and then navigate back to the Title Scene, and then go back to the Options Scene, it should still be deselected.

Adding Background Music

Now that our global state is keeping track of the music options, we will work on adding some background music to our game. For our background music, we will add this to our Title Scene, and we will need to check if the setting for music enabled is set to true. To do this, open TitleScene.js and add the following code at the bottom of the create function:

this.model = this.sys.game.globals.model;
if (this.model.musicOn === true) {
  this.bgMusic = this.sound.add('bgMusic', { volume: 0.5, loop: true });
  this.bgMusic.play();
}

In the code above, we did the following:

Now, to quickly test our changes, open up PreloaderScene.js and in the ready function update the this.scene.start('Options'); line to be:

this.scene.start('Title');

Now, save your code changes and in your browser, you should hear the new background music start once the game reached the Title Scene. However, if you navigate to another scene and then back to the Title Scene you will notice that our background music will start multiple times (you may need to navigate back and forth a few times to hear it).

To fix this issue, we will use our global state to track if the background music is already playing, and if it isn’t then we will start our music. In the code we just added, update the following line:

if (this.model.musicOn === true) {

to be:

if (this.model.musicOn === true && this.model.bgMusicPlaying === false) {

Then, add the following line inside that if statement:

this.model.bgMusicPlaying = true;

Now, if you save your code changes and test your game again, the background music should only start one time.

Stoping the Background Music

Now that we our background music working in our game, we need to update the logic in our Options Scene to pause the background music when the player disables the music in our game. To do this, we will need to make our `bgMusic` Game Object available in our Options Scene, and one way to do this is to store a reference to it in our globals object.

First, we will add a new property called bgMusic to our globals object. To do this, open index.js and update the following line:

this.globals = { model };

to be:

this.globals = { model, bgMusic: null };

Next, to store a reference to our background music Game Object, open TitleScene.js and add the following line inside the if statement that checks if the background music should be added:

this.sys.game.globals.bgMusic = this.bgMusic;

This code block should now look like this:

if (this.model.musicOn === true && this.model.bgMusicPlaying === false) {
  this.bgMusic = this.sound.add('bgMusic', { volume: 0.5, loop: true });
  this.bgMusic.play();
  this.model.bgMusicPlaying = true;
  this.sys.game.globals.bgMusic = this.bgMusic;
}

Now that we have stored a referenced to this Game Object, we can now access it in our Options Scene. Open OptionsScene.js, and replace all of the code in the updateAudio function with the following code:

if (this.model.musicOn === false) {
  this.musicButton.setTexture('box');
  this.sys.game.globals.bgMusic.stop();
  this.model.bgMusicPlaying = false;
} else {
  this.musicButton.setTexture('checkedBox');
  if (this.model.bgMusicPlaying === false) {
    this.sys.game.globals.bgMusic.play();
    this.model.bgMusicPlaying = true;
  }
}

if (this.model.soundOn === false) {
  this.soundButton.setTexture('box');
} else {
  this.soundButton.setTexture('checkedBox');
}

Let’s review the code we just added:

Now, if you save your code changes and test your game in the browser, you should be able to access the Options Scene and then start and stop the background music by clicking on the Music Enabled checkbox.

Refactoring

With our background music completed, we can now start working on refactoring some of our code. Currently, in our game template we have 4 different buttons that when they are clicked will start a different scene. To clean up our code, and make it easier to add one of these buttons later, we are going to create a new class and move this logic there.

To do this, create a new folder in your src folder that is called Objects. Then, in this new folder create a new file called Button.js.  In this file, add the following code:

import 'phaser';

export default class Button extends Phaser.GameObjects.Container {
  constructor(scene, x, y, key1, key2, text, targetScene) {
    super(scene);
    this.scene = scene;
    this.x = x;
    this.y = y;

    this.button = this.scene.add.sprite(0, 0, key1).setInteractive();
    this.text = this.scene.add.text(0, 0, text, { fontSize: '32px', fill: '#fff' });
    Phaser.Display.Align.In.Center(this.text, this.button);

    this.add(this.button);
    this.add(this.text);

    this.button.on('pointerdown', function () {
      this.scene.scene.start(targetScene);
    }.bind(this));

    this.button.on('pointerover', function () {
      this.button.setTexture(key2);
    }.bind(this));

    this.button.on('pointerout', function () {
      this.button.setTexture(key1);
    }.bind(this));

    this.scene.add.existing(this);
  }
}

Now, this code should like similar to the code that is already used in our Title and Options Scenes. However, there are a few things that are different:

Now that we have created our new class, we can update our existing scenes to use this code. First, in OptionsScene.js replace the following code in the create function:

this.menuButton = this.add.sprite(400, 500, 'blueButton1').setInteractive();
this.menuText = this.add.text(0, 0, 'Menu', { fontSize: '32px', fill: '#fff' });
Phaser.Display.Align.In.Center(this.menuText, this.menuButton);

this.menuButton.on('pointerdown', function (pointer) {
  this.scene.start('Title');
}.bind(this));

with this line:

this.menuButton = new Button(this, 400, 500, 'blueButton1', 'blueButton2', 'Menu', 'Title');

Then, at the top of the file we will need to import our new class. To do this, add the following line below the import 'phaser' line:

import Button from '../Objects/Button';

Now, if save your code changes and view your game in the browser, you should be able to visit the Options Scene, and it should look the same as before.

Next, we will update the Title Scene. Open TitleScene.js, and add the following line at the top of the file below the import 'phaser' line:

import Button from '../Objects/Button';

Next, we will remove all of the old code for the three buttons and replace that code with code that will use the new Button class. To do this, replace all of the code in the create function with the following code:

create () {
  // Game
  this.gameButton = new Button(this, config.width/2, config.height/2 - 100, 'blueButton1', 'blueButton2', 'Play', 'Game');

  // Options
  this.optionsButton = new Button(this, config.width/2, config.height/2, 'blueButton1', 'blueButton2', 'Options', 'Options');

  // Credits
  this.creditsButton = new Button(this, config.width/2, config.height/2 + 100, 'blueButton1', 'blueButton2', 'Credits', 'Credits');

  this.model = this.sys.game.globals.model;
  if (this.model.musicOn === true && this.model.bgMusicPlaying === false) {
    this.bgMusic = this.sound.add('bgMusic', { volume: 0.5, loop: true });
    this.bgMusic.play();
    this.model.bgMusicPlaying = true;
    this.sys.game.globals.bgMusic = this.bgMusic;
  }
}

Finally, you can remove the following code from TitleScene.js:

centerButton (gameObject, offset = 0) {
  Phaser.Display.Align.In.Center(
    gameObject,
    this.add.zone(config.width/2, config.height/2 - offset * 100, config.width, config.height)
  );
}

centerButtonText (gameText, gameButton) {
  Phaser.Display.Align.In.Center(
    gameText,
    gameButton
  );
}

Now, if you save your code changes and view your game in the browser, the Title Scene should work and look the same way as before.

Conclusion

Now that we have finished refactoring the code for our Buttons, that brings this tutorial to a close. In summary, this tutorial showed you how to create a basic Phaser project template that you will be able to reuse and extend. Some examples of ways this template can be enhanced are:

I hope you enjoyed all of these tutorials and found them helpful. If you have any questions, or suggestions on what we should cover next, please let us know in the comments below.

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