Spawning copies of a sprite from a class function

Phaser 3
1

Hi, I have been trying to create a simple game where you can run over zombies with a car, I want the zombies to spawn off the screen and then move down into the screen and be able to be collided with and destroyed by the car. I have been attempting to test enabling and disabling the collider using keys but I cannot figure out how to detect a collision. I need to be able to keep a track of how many of these sprites have been destroyed in a variable, as well as have multiple copies of it on the scene at once. What is the best way to go about this. Here is some of my code, I won’t post it all as its split across multiple files and classes.

This is my main file where I create and update objects. Inside the update function is where I want to call the function from my Zombie class in order to spawn new zombies.

class zombieDriver extends Phaser.Scene {
    constructor(){
        super("mainGame");
    }

    create(){

        //Create Backgorund
        background = this.background = this.add.tileSprite(0, 0, config.width, config.height, "background");
        background.setOrigin(0,0);

        //Create vehicles physics group
        vehicles = this.physics.add.group();

        //Create Main player car
        player1 = this.physics.add.existing(new Player(this, config.width/2, config.height/2, 'car'));
        vehicles.add(player1);
        player1.depth = 100;// set depth so car is on top

        //Create Cursors input detection
        cursors = this.input.keyboard.createCursorKeys();
        keyC = this.input.keyboard.addKey(Phaser.Input.Keyboard.KeyCodes.C);
        keyX = this.input.keyboard.addKey(Phaser.Input.Keyboard.KeyCodes.X);

        //Create objects physics group
        objects = this.physics.add.group();

        //Create Zombie instance
        zombie = this.physics.add.existing(new Zombie(this, config.width/2, config.height/2 - 100, 'zombie'));
        objects.add(zombie);
        zombie.depth = 99; // set the depth so zombie is beneath car
        
        
    }
    
    update() {
        //Animate Background
        background.tilePositionY -= BACKGROUNDSPEED;
        //Call update player function from player class
        player1.updatePlayer(player1,cursors);

        zombie.spawnZombies(zombie,keyC,keyX);
    }
}

Then this is my Zombie class.

class Zombie extends Phaser.Physics.Arcade.Sprite{
    constructor(scene, x, y, texture) {
        super(scene, x, y, texture);
        scene.add.existing(this);
    }
    spawnZombies(zombie, keyC){
        if(keyC.isDown){
            zombie.setActive(false).setVisible(false);
            //zombie.checkCollision = true;
            //zombie.destroy();
        }
        if(keyX.isDown){
            zombie.setActive(true).setVisible(true);
        }
    }
}

At the moment I can only enable and disable the zombie I have created already in the main create function, however I want to be able to create new instances of the zombie from within the zombie class, specifically my spawnZomibes function.

game
game592×739 56.4 KB

So basically I’m asking how to spawn the zombie from the function in the Zombie class. I can then figure out how to repeatedly spawn them off-screen and move them down for the player to hit and rack up a score.

2

I would do the zombie spawning in the scene (or possibly a group class, if you want to make one). It doesn’t really make sense in Zombie, since that’s a zombie already existing. And you’ll need a collider. Make sure the car is moving with velocity.

class zombieDriver extends Phaser.Scene {
  // …
  create () {
    // …
    this.physics.add.collider(player1, objects);
  }

  update () {
    // …
    if (keyC.isDown) {
      this.spawnZombie(0, 0);
    }
  }

  spawnZombie (x, y) {
    return objects.add(new Zombie(this, x, y, 'zombie'));
  }
}
3

Perfect thank you, just got back to this project after a data loss, am almost back to where it was when i made this post. Just gonna re-draw my zombie sprite and give this a go now.

4

Just implemented this and it has worked great. Was wondering what i would do if i wanted to detect a collision with each zombie and add to a score counter? @samme

6

Usually a player vs. zombie overlap collider that destroys the zombie, increments a score variable, and updates a text game object.

7

Hi @samme , i’ve had a super productive 2 days and i’ve actually finished the game now. Thanks for the help