Get the full commented source code of

HTML5 Suika Watermelon Game

Talking about Endless Runner game, Game development, HTML5, Javascript and Phaser.

Here we go with the 4th part of the HTML5 endless runner prototype powered by Phaser and Arcade physics.

Time for a small recap: in first step, I was able to set up a basic endless runner with double jump and room for customization using object pooling to save resources.

In second step I added even more room for customization and – most important – a player animation.

In third step I added texture to platforms – no more white boxes – and coins to collect. Coins have their own animation and once collected they disappear in a way similar to the one you used to see in Super Mario series.

Now it’s time to add a scrolling parallax background, which is made by a series of images moving at a slower speed than the platform, giving the illusion they are moving in the distance.

To create this effect, I created four mountains with my script to programmatically draw mountains, which I randomly placed as background.

Unlike platforms and coins, this time I didn’t recycle the mountains using object pooling, I just placed mountains to cover an area way wider – two times, actually – than game width, then simply moving a mountain to the far right once it leaves the screen to the left.

Have a look at our hero running and jumping over platforms:

Click or tap to jump or double jump.

Enjoy the commented source code:

let game;

// global game options
let gameOptions = {

    // platform speed range, in pixels per second
    platformSpeedRange: [300, 300],

    // mountain speed, in pixels per second
    mountainSpeed: 80,

    // spawn range, how far should be the rightmost platform from the right edge
    // before next platform spawns, in pixels
    spawnRange: [80, 300],

    // platform width range, in pixels
    platformSizeRange: [90, 300],

    // a height range between rightmost platform and next platform to be spawned
    platformHeightRange: [-5, 5],

    // a scale to be multiplied by platformHeightRange
    platformHeighScale: 20,

    // platform max and min height, as screen height ratio
    platformVerticalLimit: [0.4, 0.8],

    // player gravity
    playerGravity: 900,

    // player jump force
    jumpForce: 400,

    // player starting X position
    playerStartPosition: 200,

    // consecutive jumps allowed
    jumps: 2,

    // % of probability a coin appears on the platform
    coinPercent: 25
}

window.onload = function() {

    // object containing configuration options
    let gameConfig = {
        type: Phaser.AUTO,
        width: 1334,
        height: 750,
        scene: [preloadGame, playGame],
        backgroundColor: 0x0c88c7,

        // physics settings
        physics: {
            default: "arcade"
        }
    }
    game = new Phaser.Game(gameConfig);
    window.focus();
    resize();
    window.addEventListener("resize", resize, false);
}

// preloadGame scene
class preloadGame extends Phaser.Scene{
    constructor(){
        super("PreloadGame");
    }
    preload(){
        this.load.image("platform", "platform.png");

        // player is a sprite sheet made by 24x48 pixels
        this.load.spritesheet("player", "player.png", {
            frameWidth: 24,
            frameHeight: 48
        });

        // the coin is a sprite sheet made by 20x20 pixels
        this.load.spritesheet("coin", "coin.png", {
            frameWidth: 20,
            frameHeight: 20
        });

        // mountains are a sprite sheet made by 512x512 pixels
        this.load.spritesheet("mountain", "mountain.png", {
            frameWidth: 512,
            frameHeight: 512
        });
    }
    create(){

        // setting player animation
        this.anims.create({
            key: "run",
            frames: this.anims.generateFrameNumbers("player", {
                start: 0,
                end: 1
            }),
            frameRate: 8,
            repeat: -1
        });

        // setting coin animation
        this.anims.create({
            key: "rotate",
            frames: this.anims.generateFrameNumbers("coin", {
                start: 0,
                end: 5
            }),
            frameRate: 15,
            yoyo: true,
            repeat: -1
        });

        this.scene.start("PlayGame");
    }
}

// playGame scene
class playGame extends Phaser.Scene{
    constructor(){
        super("PlayGame");
    }
    create(){

        // group with all active mountains.
        this.mountainGroup = this.add.group();

        // group with all active platforms.
        this.platformGroup = this.add.group({

            // once a platform is removed, it's added to the pool
            removeCallback: function(platform){
                platform.scene.platformPool.add(platform)
            }
        });

        // platform pool
        this.platformPool = this.add.group({

            // once a platform is removed from the pool, it's added to the active platforms group
            removeCallback: function(platform){
                platform.scene.platformGroup.add(platform)
            }
        });

        // group with all active coins.
        this.coinGroup = this.add.group({

            // once a coin is removed, it's added to the pool
            removeCallback: function(coin){
                coin.scene.coinPool.add(coin)
            }
        });

        // coin pool
        this.coinPool = this.add.group({

            // once a coin is removed from the pool, it's added to the active coins group
            removeCallback: function(coin){
                coin.scene.coinGroup.add(coin)
            }
        });

        // adding a mountain
        this.addMountains()

        // keeping track of added platforms
        this.addedPlatforms = 0;

        // number of consecutive jumps made by the player so far
        this.playerJumps = 0;

        // adding a platform to the game, the arguments are platform width, x position and y position
        this.addPlatform(game.config.width, game.config.width / 2, game.config.height * gameOptions.platformVerticalLimit[1]);

        // adding the player;
        this.player = this.physics.add.sprite(gameOptions.playerStartPosition, game.config.height * 0.7, "player");
        this.player.setGravityY(gameOptions.playerGravity);
        this.player.setDepth(2);

        // setting collisions between the player and the platform group
        this.physics.add.collider(this.player, this.platformGroup, function(){

            // play "run" animation if the player is on a platform
            if(!this.player.anims.isPlaying){
                this.player.anims.play("run");
            }
        }, null, this);

        // setting collisions between the player and the coin group
        this.physics.add.overlap(this.player, this.coinGroup, function(player, coin){
            this.tweens.add({
                targets: coin,
                y: coin.y - 100,
                alpha: 0,
                duration: 800,
                ease: "Cubic.easeOut",
                callbackScope: this,
                onComplete: function(){
                    this.coinGroup.killAndHide(coin);
                    this.coinGroup.remove(coin);
                }
            });
        }, null, this);

        // checking for input
        this.input.on("pointerdown", this.jump, this);
    }

    // adding mountains
    addMountains(){
        let rightmostMountain = this.getRightmostMountain();
        if(rightmostMountain < game.config.width * 2){
            let mountain = this.physics.add.sprite(rightmostMountain + Phaser.Math.Between(100, 350), game.config.height + Phaser.Math.Between(0, 100), "mountain");
            mountain.setOrigin(0.5, 1);
            mountain.body.setVelocityX(gameOptions.mountainSpeed * -1)
            this.mountainGroup.add(mountain);
            if(Phaser.Math.Between(0, 1)){
                mountain.setDepth(1);
            }
            mountain.setFrame(Phaser.Math.Between(0, 3))
            this.addMountains()
        }
    }

    // getting rightmost mountain x position
    getRightmostMountain(){
        let rightmostMountain = -200;
        this.mountainGroup.getChildren().forEach(function(mountain){
            rightmostMountain = Math.max(rightmostMountain, mountain.x);
        })
        return rightmostMountain;
    }

    // the core of the script: platform are added from the pool or created on the fly
    addPlatform(platformWidth, posX, posY){
        this.addedPlatforms ++;
        let platform;
        if(this.platformPool.getLength()){
            platform = this.platformPool.getFirst();
            platform.x = posX;
            platform.y = posY;
            platform.active = true;
            platform.visible = true;
            this.platformPool.remove(platform);
            let newRatio =  platformWidth / platform.displayWidth;
            platform.displayWidth = platformWidth;
            platform.tileScaleX = 1 / platform.scaleX;
        }
        else{
            platform = this.add.tileSprite(posX, posY, platformWidth, 32, "platform");
            this.physics.add.existing(platform);
            platform.body.setImmovable(true);
            platform.body.setVelocityX(Phaser.Math.Between(gameOptions.platformSpeedRange[0], gameOptions.platformSpeedRange[1]) * -1);
            platform.setDepth(2);
            this.platformGroup.add(platform);
        }
        this.nextPlatformDistance = Phaser.Math.Between(gameOptions.spawnRange[0], gameOptions.spawnRange[1]);

        // is there a coin over the platform?
        if(this.addedPlatforms > 1){
            if(Phaser.Math.Between(1, 100) <= gameOptions.coinPercent){
                if(this.coinPool.getLength()){
                    let coin = this.coinPool.getFirst();
                    coin.x = posX;
                    coin.y = posY - 96;
                    coin.alpha = 1;
                    coin.active = true;
                    coin.visible = true;
                    this.coinPool.remove(coin);
                }
                else{
                    let coin = this.physics.add.sprite(posX, posY - 96, "coin");
                    coin.setImmovable(true);
                    coin.setVelocityX(platform.body.velocity.x);
                    coin.anims.play("rotate");
                    coin.setDepth(2);
                    this.coinGroup.add(coin);
                }
            }
        }
    }

    // the player jumps when on the ground, or once in the air as long as there are jumps left and the first jump was on the ground
    jump(){
        if(this.player.body.touching.down || (this.playerJumps > 0 && this.playerJumps < gameOptions.jumps)){
            if(this.player.body.touching.down){
                this.playerJumps = 0;
            }
            this.player.setVelocityY(gameOptions.jumpForce * -1);
            this.playerJumps ++;

            // stops animation
            this.player.anims.stop();
        }
    }

    update(){

        // game over
        if(this.player.y > game.config.height){
            this.scene.start("PlayGame");
        }
        this.player.x = gameOptions.playerStartPosition;

        // recycling platforms
        let minDistance = game.config.width;
        let rightmostPlatformHeight = 0;
        this.platformGroup.getChildren().forEach(function(platform){
            let platformDistance = game.config.width - platform.x - platform.displayWidth / 2;
            if(platformDistance < minDistance){
                minDistance = platformDistance;
                rightmostPlatformHeight = platform.y;
            }
            if(platform.x < - platform.displayWidth / 2){
                this.platformGroup.killAndHide(platform);
                this.platformGroup.remove(platform);
            }
        }, this);

        // recycling coins
        this.coinGroup.getChildren().forEach(function(coin){
            if(coin.x < - coin.displayWidth / 2){
                this.coinGroup.killAndHide(coin);
                this.coinGroup.remove(coin);
            }
        }, this);

        // recycling mountains
        this.mountainGroup.getChildren().forEach(function(mountain){
            if(mountain.x < - mountain.displayWidth){
                let rightmostMountain = this.getRightmostMountain();
                mountain.x = rightmostMountain + Phaser.Math.Between(100, 350);
                mountain.y = game.config.height + Phaser.Math.Between(0, 100);
                mountain.setFrame(Phaser.Math.Between(0, 3))
                if(Phaser.Math.Between(0, 1)){
                    mountain.setDepth(1);
                }
            }
        }, this);

        // adding new platforms
        if(minDistance > this.nextPlatformDistance){
            let nextPlatformWidth = Phaser.Math.Between(gameOptions.platformSizeRange[0], gameOptions.platformSizeRange[1]);
            let platformRandomHeight = gameOptions.platformHeighScale * Phaser.Math.Between(gameOptions.platformHeightRange[0], gameOptions.platformHeightRange[1]);
            let nextPlatformGap = rightmostPlatformHeight + platformRandomHeight;
            let minPlatformHeight = game.config.height * gameOptions.platformVerticalLimit[0];
            let maxPlatformHeight = game.config.height * gameOptions.platformVerticalLimit[1];
            let nextPlatformHeight = Phaser.Math.Clamp(nextPlatformGap, minPlatformHeight, maxPlatformHeight);
            this.addPlatform(nextPlatformWidth, game.config.width + nextPlatformWidth / 2, nextPlatformHeight);
        }
    }
};
function resize(){
    let canvas = document.querySelector("canvas");
    let windowWidth = window.innerWidth;
    let windowHeight = window.innerHeight;
    let windowRatio = windowWidth / windowHeight;
    let gameRatio = game.config.width / game.config.height;
    if(windowRatio < gameRatio){
        canvas.style.width = windowWidth + "px";
        canvas.style.height = (windowWidth / gameRatio) + "px";
    }
    else{
        canvas.style.width = (windowHeight * gameRatio) + "px";
        canvas.style.height = windowHeight + "px";
    }
}

Next time I’ll add some deadly object, meanwhile download the source code.

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