Different collision behavior for different directions

[kurhlaa]

Hello,

I've modified a little one labs example (first game). I have 1 ground platform and all stars falling on it, and a player. Plus collisions between everything, even between stars themselves. Player initially is in the middle of the screen and stars.

If I move to the right - stars are moving, hitting each one and all joining the line; so you hit 1 and move it, then 2'nd star joins, then 3'rd, 4'th and so on. That's correct, you get all stars in a line next to each other.

The issue appears when you move to the left - I'm able to join only 2 stars - all other acts like physicsless and player/stars just go through them. So you get max 2 stars in a row.

Is this an arcade/collisions bug? What can I do to make collisions always be the same and objects do not go through each other? If I comment out the internals of my function collideElem - results for different directions are still different. I use it for stopping the star after a collision.

Here is my testing code which is runnable at labs.phaser.io:

var config = {
    type: Phaser.AUTO,
    width: 800,
    height: 600,
    physics: {
        default: 'arcade',
        arcade: {
            gravity: { y: 300 },
            debug: false
        }
    },
    scene: {
        preload: preload,
        create: create,
        update: update
    }
};

var player;
var stars;
var platforms;
var cursors;

var game = new Phaser.Game(config);

function preload ()
{
    this.load.image('sky', 'src/games/firstgame/assets/sky.png');
    this.load.image('ground', 'src/games/firstgame/assets/platform.png');
    this.load.image('star', 'src/games/firstgame/assets/star.png');
    this.load.spritesheet('dude', 'src/games/firstgame/assets/dude.png', { frameWidth: 32, frameHeight: 48 });
}

function create ()
{
    this.add.image(400, 300, 'sky');

    platforms = this.physics.add.staticGroup();

    platforms.create(400, 568, 'ground').setScale(2).refreshBody();

    player = this.physics.add.sprite(300, 450, 'dude');
    player.setCollideWorldBounds(true);

    this.anims.create({
        key: 'left',
        frames: this.anims.generateFrameNumbers('dude', { start: 0, end: 3 }),
        frameRate: 10,
        repeat: -1
    });

    this.anims.create({
        key: 'turn',
        frames: [ { key: 'dude', frame: 4 } ],
        frameRate: 20
    });

    this.anims.create({
        key: 'right',
        frames: this.anims.generateFrameNumbers('dude', { start: 5, end: 8 }),
        frameRate: 10,
        repeat: -1
    });

    cursors = this.input.keyboard.createCursorKeys();

    stars = this.physics.add.group({
        key: 'star',
        repeat: 11,
        setXY: { x: 12, y: 0, stepX: 70 }
    });

    this.physics.add.collider(player, platforms);
    this.physics.add.collider(stars, platforms);

    this.physics.add.collider(player, stars, collideElem, null, this);
    this.physics.add.collider(stars, stars, collideElem, null, this);

}

function collideElem(obj1, obj2) {
    obj2.body.setVelocityX(0);
    obj2.body.setVelocityX(0);
}

function update ()
{
    if (cursors.left.isDown)
    {
        player.setVelocityX(-160);
        player.anims.play('left', true);
    }
    else if (cursors.right.isDown)
    {
        player.setVelocityX(160);
        player.anims.play('right', true);
    }
    else
    {
        player.setVelocityX(0);
        player.anims.play('turn');
    }

    if (cursors.up.isDown && player.body.touching.down)
    {
        player.setVelocityY(-330);
    }
}