Phaser 3 "Space" example without drag

space.js

var config = {
    type: Phaser.AUTO,
    width: 800,
    height: 600,
    parent: 'phaser-example',
    physics: {
        default: 'arcade',
        arcade: {
            debug: true
        }
    },
    scene: {
        preload: preload,
        create: create,
        update: update
    },
    pixelArt: false,
    roundPixels: false
};

var bg;
var stars;
var ship;
var bullets;
var lastFired = 0;
var cursors;
var fire;

var game = new Phaser.Game(config);

function preload ()
{
    this.load.image('background', 'assets/tests/space/nebula.jpg');
    this.load.image('stars', 'assets/tests/space/stars.png');
    this.load.atlas('space', 'assets/tests/space/space.png', 'assets/tests/space/space.json');
}

function create ()
{
    var Bullet = new Phaser.Class({

        Extends: Phaser.Physics.Arcade.Image,

        initialize:

        function Bullet (scene)
        {
            //Phaser.Physics.Arcade.Image.call(this, scene, 0, 0, 'space', 'blaster');
            Phaser.Physics.Arcade.Image.call(this, scene, 0, 0, 'space', 'blaster');

            this.setBlendMode(1);
            this.setDepth(1);

            this.speed = 1000;
            //this.lifespan = 1000;

            //this._temp = new Phaser.Math.Vector2();
        },

        fire: function (ship, target, laserMount)
        {
            this.lifespan = 1000;
            //this.setSize(10, 10, true);
            this.setDisplaySize(20, 20, true);
            this.setActive(true);
            this.setVisible(true);

            this.direction = Math.atan( (target.x-this.x) / (target.y-this.y));
            this.rotation = ship.rotation;
            this.setPosition(laserMount.x, laserMount.y); // Initial position
            

            /*if (target.y >= this.y) {
                this.xSpeed = this.speed*Math.sin(this.direction);
                this.ySpeed = this.speed*Math.cos(this.direction);
            } else {
                this.xSpeed = -this.speed*Math.sin(this.direction);
                this.ySpeed = -this.speed*Math.cos(this.direction);
            }*/
            // this.setRotation(ship.rotation);
            //this.setAngle(ship.body.rotation);
            //this.setPosition(ship.x, ship.y);
            //this.body.reset(ship.x, ship.y);

            //ship.body.advancePosition(10, this._temp);

            // this.setPosition(this._temp.x, this._temp.y);
            // this.body.reset(this._temp.x, this._temp.y);

            //  if ship is rotating we need to add it here
            // var a = ship.body.angularVelocity;

            // if (ship.body.speed !== 0)
            // {
            //     var angle = Math.atan2(ship.body.velocity.y, ship.body.velocity.x);
            // }
            // else
            // {
                //var angle = Phaser.Math.DegToRad(ship.body.rotation);
            // }

            //this.body.world.velocityFromRotation(this.rotation, this.speed + ship.body.speed, this.body.velocity);
            this.scene.physics.velocityFromRotation(this.rotation, this.speed, this.body.velocity);

            this.body.velocity.x *= 2;
            this.body.velocity.y *= 2;
            //this.body.velocity.x =
        },

        update: function (time, delta)
        {
            this.lifespan -= delta;

            if (this.lifespan <= 0)
            {
                this.setActive(false);
                this.setVisible(false);
                this.body.stop();
            }
        }

    });

    //  Prepare some spritesheets and animations

    this.textures.addSpriteSheetFromAtlas('mine-sheet', { atlas: 'space', frame: 'mine', frameWidth: 64 });
    this.textures.addSpriteSheetFromAtlas('asteroid1-sheet', { atlas: 'space', frame: 'asteroid1', frameWidth: 96 });
    this.textures.addSpriteSheetFromAtlas('asteroid2-sheet', { atlas: 'space', frame: 'asteroid2', frameWidth: 96 });
    this.textures.addSpriteSheetFromAtlas('asteroid3-sheet', { atlas: 'space', frame: 'asteroid3', frameWidth: 96 });
    this.textures.addSpriteSheetFromAtlas('asteroid4-sheet', { atlas: 'space', frame: 'asteroid4', frameWidth: 64 });

    this.anims.create({ key: 'mine-anim', frames: this.anims.generateFrameNumbers('mine-sheet', { start: 0, end: 15 }), frameRate: 20, repeat: -1 });
    this.anims.create({ key: 'asteroid1-anim', frames: this.anims.generateFrameNumbers('asteroid1-sheet', { start: 0, end: 24 }), frameRate: 20, repeat: -1 });
    this.anims.create({ key: 'asteroid2-anim', frames: this.anims.generateFrameNumbers('asteroid2-sheet', { start: 0, end: 24 }), frameRate: 20, repeat: -1 });
    this.anims.create({ key: 'asteroid3-anim', frames: this.anims.generateFrameNumbers('asteroid3-sheet', { start: 0, end: 24 }), frameRate: 20, repeat: -1 });
    this.anims.create({ key: 'asteroid4-anim', frames: this.anims.generateFrameNumbers('asteroid4-sheet', { start: 0, end: 24 }), frameRate: 20, repeat: -1 });

    //  World size is 8000 x 6000

    bg = this.add.tileSprite(400, 300, 800, 600, 'background').setScrollFactor(0);

    //  Add our planets, etc

    this.add.image(512, 680, 'space', 'blue-planet').setOrigin(0).setScrollFactor(0.6);
    this.add.image(2833, 1246, 'space', 'brown-planet').setOrigin(0).setScrollFactor(0.6);
    this.add.image(3875, 531, 'space', 'sun').setOrigin(0).setScrollFactor(0.6);
    var galaxy = this.add.image(5345 + 1024, 327 + 1024, 'space', 'galaxy').setBlendMode(1).setScrollFactor(0.6);
    this.add.image(908, 3922, 'space', 'gas-giant').setOrigin(0).setScrollFactor(0.6);
    this.add.image(3140, 2974, 'space', 'brown-planet').setOrigin(0).setScrollFactor(0.6).setScale(0.8).setTint(0x882d2d);
    this.add.image(6052, 4280, 'space', 'purple-planet').setOrigin(0).setScrollFactor(0.6);

    for (var i = 0; i < 8; i++)
    {
        this.add.image(Phaser.Math.Between(0, 8000), Phaser.Math.Between(0, 6000), 'space', 'eyes').setBlendMode(1).setScrollFactor(0.8);
    }

    stars = this.add.tileSprite(400, 300, 800, 600, 'stars').setScrollFactor(0);

    var particles = this.add.particles('space');

    var emitter = particles.createEmitter({
        frame: 'blue',
        speed: 100,
        lifespan: {
            onEmit: function (particle, key, t, value)
            {
                return Phaser.Math.Percent(ship.body.speed, 0, 300) * 2000;
            }
        },
        alpha: {
            onEmit: function (particle, key, t, value)
            {
                return Phaser.Math.Percent(ship.body.speed, 0, 300);
            }
        },
        angle: {
            onEmit: function (particle, key, t, value)
            {
                var v = Phaser.Math.Between(-10, 10);
                return (ship.angle - 180) + v;
            }
        },
        scale: { start: 0.3, end: 0 },
        blendMode: 'ADD'
    });

    bullets = this.physics.add.group({
        classType: Bullet,
        maxSize: 30,
        runChildUpdate: true
    });

    ship = this.physics.add.image(4000, 3000, 'space', 'ship').setDepth(2);
    ship
      .setOrigin(0.5, 0.5)
      .setDisplaySize(30, 30)
      .setDrag(0)
      .setAngularDrag(0)
      .setMaxVelocity(1000);
    
    reticle = this.physics.add.sprite(ship.x, ship.y + 50, 'target');
    reticle.setOrigin(0.5, 0.5).setDisplaySize(10, 10);

    laserMount = this.physics.add.sprite(ship.x + 25 * Math.cos(ship.rotation), ship.y + 25 * Math.sin(ship.rotation), 'laserMount');
    laserMount.setOrigin(0.5, 0.5).setDisplaySize(5, 5);

    emitter.startFollow(ship);

    this.cameras.main.startFollow(ship);
    //this.cameras.main.zoom = 0.5

    //cursors = this.input.keyboard.createCursorKeys();
    keyBackThrust = this.input.keyboard.addKey(Phaser.Input.Keyboard.KeyCodes.S);
    keyFwdThrust = this.input.keyboard.addKey(Phaser.Input.Keyboard.KeyCodes.W);
    keyLeft = this.input.keyboard.addKey(Phaser.Input.Keyboard.KeyCodes.A);
    keyRight = this.input.keyboard.addKey(Phaser.Input.Keyboard.KeyCodes.D);
    fire = false;
    //this.input.mouse.add


    // Pointer lock will only work after mousedown
    game.canvas.addEventListener('mousedown', function () {
        game.input.mouse.requestPointerLock();
    });

    this.input.on('pointermove', function (pointer) {
        if (this.input.mouse.locked)
        {
            reticle.x += pointer.movementX;
            reticle.y += pointer.movementY;
        }
    }, this);

    // Fires bullets if mousebuttons down
    this.input.on('pointerdown', function (pointer) {
        fire = true;
    }, this);

    this.input.on('pointerup', function (pointer) {
        fire = false;
    }, this);    

    this.add.sprite(4300, 3000).play('asteroid1-anim');

    this.tweens.add({
        targets: galaxy,
        angle: 360,
        duration: 100000,
        ease: 'Linear',
        loop: -1
    });

    text = this.add.text(32, 32).setScrollFactor(0).setFontSize(10).setColor('#ffffff');
}

function constrainReticle(reticle)
{
    var distX = reticle.x-ship.x; // X distance between player & reticle
    var distY = reticle.y-ship.y; // Y distance between player & reticle

    // Ensures reticle cannot be moved offscreen (player follow)
    if (distX > 200)
        reticle.x = ship.x+200;
    else if (distX < -200)
        reticle.x = ship.x-200;

    if (distY > 200)
        reticle.y = ship.y+200;
    else if (distY < -200)
        reticle.y = ship.y-200;
}

function update (time, delta)
{
    // Rotates player to face towards reticle
    ship.rotation = Phaser.Math.Angle.Between(ship.x, ship.y, reticle.x, reticle.y);

    var noCursorDown = true;
    var downVec = Phaser.Math.Vector2.ZERO;
    var upVec = Phaser.Math.Vector2.ZERO;
    var leftVec = Phaser.Math.Vector2.ZERO;
    var rightVec = Phaser.Math.Vector2.ZERO;

    if (keyLeft.isDown) {
        noCursorDown = false;
        leftVec = this.physics.velocityFromAngle(ship.angle - 90, 200);
        //ship.body.acceleration = leftVec;        
    }

    if (keyRight.isDown) {
        noCursorDown = false;
        rightVec = this.physics.velocityFromAngle(ship.angle + 90, 200);
        //ship.body.acceleration = rightVec;        
    }

    if (keyBackThrust.isDown) {
        noCursorDown = false;
        downVec = this.physics.velocityFromAngle(ship.angle - 180, 100);
        //ship.body.acceleration = downVec;
    }

    if (keyFwdThrust.isDown) {
        noCursorDown = false;
        upVec = this.physics.velocityFromAngle(ship.angle, 600);
        //ship.body.acceleration = upVec;
    }
    
    var addVec = new Phaser.Math.Vector2(
        downVec.x + upVec.x + leftVec.x + rightVec.x,
        downVec.y + upVec.y + leftVec.y + rightVec.y
    );

    if (noCursorDown) {
        ship.setAcceleration(0);
    } else {
        ship.body.acceleration = addVec;
    }
    
    reticle.body.velocity.x = ship.body.velocity.x;
    reticle.body.velocity.y = ship.body.velocity.y;
    // Constrain position of constrainReticle
    //constrainReticle(reticle);

    laserMount.setPosition(ship.x + 25 * Math.cos(ship.rotation), ship.y + 25 * Math.sin(ship.rotation));
    laserMount.body.velocity.x = ship.body.velocity.x;
    laserMount.body.velocity.y = ship.body.velocity.y;

    if (fire && time > lastFired)
    {
        var bullet = bullets.get();

        if (bullet)
        {
            bullet.fire(ship, reticle, laserMount);

            lastFired = time + 100;
        }
    }

    bg.tilePositionX += ship.body.deltaX() * 0.5;
    bg.tilePositionY += ship.body.deltaY() * 0.5;

    stars.tilePositionX += ship.body.deltaX() * 2;
    stars.tilePositionY += ship.body.deltaY() * 2;

    text.setText([
        "up:   (" + upVec.x + ", " + upVec.y + "), down:  (" + downVec.x + ", " + downVec.y + ")",
        "left: (" + leftVec.x + ", " + leftVec.y + "), right: (" + rightVec.x + ", " + rightVec.y + ")",
        "res:  (" + addVec.x + ", " + addVec.y + ")",
        "vel:  (" + ship.body.velocity.x + ", " + ship.body.velocity.y + "), pos: (" + ship.x + ", " + ship.y + ")",
    ]);
}