Incomplete collisions in Arcade when pushing objects

[inmylo]

• Phaser Version: v3.16.0 Beta 2
• Physics: Arcade
• Browser: Chromium

There is a collision bug when 1 object pushes another - at some moment objects start to go through each other, like there is no collision at all.

In the example code below (for labs.phaser.io) I have 2 ground platforms 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 go through the right platform like there is no collision - it's a 1'st issue.
If I 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 - it's a 2'nd issue.

What can I do to make collisions always work as expected? Can you please fix that?

Example Test Code

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();
    platforms.create(900, 520, 'ground');

    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);
    }
}

[inmylo]

If that's technically and theoretically not possible in Arcade - please add a physics switch to disable energy exchange, so one object can't push the other objects (just stops instead).

[photonstorm]

The immovable switch is for this.

[inmylo]

Unfortunately not a solution if I have multiple players, which all can move themselves and collide with each other - switch immovable for everybody disables collision.

So 1'st issue is not fixable?
If Not - about the 2'nd - what do you think about new switch to prevent pushing of movable objects?

[photonstorm]

I think it still wouldn't work as you need and you should switch to using Matter.

[photonstorm]

Also: https://photonstorm.github.io/phaser3-docs/Phaser.Physics.Arcade.Body.html#customSeparateX__anchor

[inmylo]

I'm Ok with replacing some Phaser's functions in my local environment, fortunately JavaScript easily allows it. I see that SeparateX does a part of job, but if I try to remove/modify lines which change velocity/position - I loose collisions or both objects are still moving. Probably something more needs to be changed. Could you guide me what do I need to edit in Phaser code to disable pushing? Just to stop an object at collision seems to be not a difficult task

[photonstorm]

Thank you for submitting this feature request. We have implemented this and the feature has been pushed to the master branch. It will be part of the next release. If you get time to build and test it for yourself we would appreciate that.

Please see the new Body.pushable property and corresponding documentation.