Phaser P2 设置碰撞组

Phaser P2 setCollisionGroup

嗨,我正在尝试让我的子弹发生碰撞,然后在与我的方块碰撞时死亡,但是当我尝试 setCollisionGroup 时,我收到以下错误:

Uncaught TypeError: Cannot read property 'mask' of undefined

它指向我这段代码:

createBullets: function(){

    //Bullets
    this.bullets = this.add.group();
    this.bullets.enableBody = true;
    this.bullets.physicsBodyType = Phaser.Physics.P2JS;
    this.bullets.createMultiple(500, 'bullet', 0, false);
    this.bullets.setAll('anchor.x', 0.5);
    this.bullets.setAll('anchor.y', 0.5);
    this.bullets.setAll('outOfBoundsKill', true);
    this.bullets.setAll('checkWorldBounds', true);    
    this.bullets.forEach(function(bullet){
      bullet.body.setCollisionGroup(this.bulletsCG);  <-------This line
      bullet.body.collides(this.bloquesCG);
    });
},

////......下面是我的另一个碰撞组:

addOneBloque: function(x, y) {
    this.bloque = this.add.sprite(x,y,'bloque');
    this.physics.p2.enable(this.bloque, false);
    this.bloque.body.velocity.x = -200;
    this.bloque.checkWorldBounds = true;
    this.bloque.outOfBoundsKill = true;
    this.bloque.body.setCollisionGroup(this.bloquesCG);
    this.bloque.body.collides(this.bulletsCG, this.resetBullet, this);
},

一切正常,直到我尝试设置 CollisionGroups,然后一切都崩溃了。任何帮助将不胜感激。

我在错误的地方声明,谢谢大佬。