Met subclass of Phaser.Sprite

Tool.js

function Tool(game, x, y, cacheKey) {
    // Call the Phaser.Sprite constructor
    Phaser.Sprite.call(this, game, x, y, cacheKey);
    // Enable physics
    this.game.physics.enable(this);
    // Set the (physics) body to be immovable
    this.body.immovable = true;
    // Center the anchor
    this.anchor.setTo(0.5, 0.5);

    // Create a group for the bullets
    this.bulletGroup = this.game.add.group();
    // Enable all create items to have (physics) bodies
    this.bulletGroup.enableBody = true;
    // Set the type of physics bodies to be ARCADE
    this.bulletGroup.physicsBodyType = Phaser.Physics.ARCADE;
    // Create 13 bullets using the 'enemyBullet' cache key
    this.bulletGroup.createMultiple(13, 'enemyBullet');
    // Check if bullets collide with world bounds
    this.bulletGroup.setAll('checkWorldBounds', true);
    // If they do collide with world bounds, they are killed
    this.bulletGroup.setAll('outOfBoundsKill', true);
    // Bullets only 'live' for 1600ms
    this.bulletGroup.setAll('lifespan', 1600);

    // Set the firing rate (how long between shooting)
    this.fireRate = 1800;
    // The time of the next shot
    this.nextFire = 0;
    // The velocity of each created or revived bullet
    this.bulletSpeed = 150;
    // The initial firing angle
    this.firingAngle = 135;

    // The 'triggerBox'
    // If another sprite is within this rectangle, shoot at them
    this.triggerBox = new Phaser.Rectangle(
            x - (this.width * 3),
            y - (this.height * 3),
            this.width * 3.5,
            this.height * 3.5);

    // The 'explosionGroup' for spawning explosions
    this.explosionGroup = new ExplosionGroup(this.game);
    
    // Set that this sprite is 'alive'
    this.alive = true;
}

Tool.prototype = Object.create(Phaser.Sprite.prototype);
Tool.prototype.constructor = Tool;

Tool.prototype.shoot = function() {
    // Is this sprite alive?
    if (this.alive) {
        // It is alive, so check if enough time has past since the last
        //  shot and that there are at least 3 bullets 'dead'
        if (this.game.time.now > this.nextFire && this.bulletGroup.countDead() > 3)
        {
            // Update the timer
            this.nextFire = this.game.time.now + this.fireRate;
            // Run for three loops
            for (var i = 0; i < 3; i += 1) {
                // Get the first 'dead' sprite
                var bullet = this.bulletGroup.getFirstDead();
                // Reset its position to the same as this sprite's position
                //  making some adjustments for where the bullets should
                //  come from for this sprite.
                bullet.reset(this.body.x + (this.width / 2), this.body.y + (this.height / 2) - 18);
                // Set the firing angle
                bullet.angle = this.firingAngle;
                // Set the firing trajectory as based on
                //  the angle and set velocity (linear diagonal motion)
                this.game.physics.arcade.velocityFromAngle(bullet.angle,
                        this.bulletSpeed,
                        bullet.body.velocity);                
                // Update the firing angle by 45 degrees
                this.firingAngle += 45;
            }
            // Reset the firing angle to 135 degrees
            this.firingAngle = 135;
        }
    }
};

Tool.prototype.kill = function() {
    // Create an explosion at this position
    this.explosionGroup.explode(this.x, this.y);
    // kill() this sprite by calling Phaser.Sprite's
    //  own kill function and passing 'this'
    Phaser.Sprite.prototype.kill.call(this);
};