Ignore gravity is not working for matter physics

[peer2p]

Version

• Phaser Version: 3.60.0

• Operating system: MacOS Ventura 13.3

• Browser: Chrome 112.0.5615.49

Description

The boolean property ignoreGravity on matter MatterJS.BodyType is not working anymore since release 3.60.0.
Although it is set to true, the body is affected by gravity.

Example Test Code

export class Bullet extends Phaser.Physics.Matter.Sprite {
constructor(...) {
super(...);
...
this.setIgnoreGravity(true);
...
}
}

Additional Information

The evaluation of the flag is missing in method Engine._bodiesApplyGravity.
This should be the correct code for this method, as it was before.
Also without typos in the jsdoc :)

/**
 * Applies a mass dependent force to all given bodies.
 * @method _bodiesApplyGravity
 * @private
 * @param {body[]} bodies
 * @param {vector} gravity
 */
Engine._bodiesApplyGravity = function(bodies, gravity) {
    var gravityScale = typeof gravity.scale !== 'undefined' ? gravity.scale : 0.001,
        bodiesLength = bodies.length;

    if ((gravity.x === 0 && gravity.y === 0) || gravityScale === 0) {
        return;
    }

    for (var i = 0; i < bodiesLength; i++) {
        var body = bodies[i];

        if (body.ignoreGravity || body.isStatic || body.isSleeping){
            continue;
        }
        
        // add the resultant force of gravity
        body.force.y += body.mass * gravity.y * gravityScale;
        body.force.x += body.mass * gravity.x * gravityScale;
    }
};

[Gathaa]

Hello , i looked for the solution online in order To apply your fix, you can create a custom plugin for Phaser 3 that patches the Engine._bodiesApplyGravity method with the corrected version. Here's what i found :

Create a new file called MatterGravityFixPlugin.js:

export class MatterGravityFixPlugin extends Phaser.Plugins.ScenePlugin {
constructor(scene, pluginManager) {
super(scene, pluginManager);
}
boot() {
const Matter = Phaser.Physics.Matter.Matter;
this.applyGravityFix(Matter);
}
applyGravityFix(Matter) {
Matter.Engine._bodiesApplyGravity = function (bodies, gravity) {
var gravityScale = typeof gravity.scale !== 'undefined' ? gravity.scale : 0.001,
bodiesLength = bodies.length;

  if ((gravity.x === 0 && gravity.y === 0) || gravityScale === 0) {
    return;
  }

  for (var i = 0; i < bodiesLength; i++) {
    var body = bodies[i];

    if (body.ignoreGravity || body.isStatic || body.isSleeping) {
      continue;
    }
    body.force.y += body.mass * gravity.y * gravityScale;
    body.force.x += body.mass * gravity.x * gravityScale;
  }
};

}
}
//////////////////////////////////////////////////////////////////////////////////
Import the plugin in your main game file:
// /////////////////////////////////////////////////////////////Code
import { MatterGravityFixPlugin } from './MatterGravityFixPlugin';
Register the plugin in your game configuration:

const config = {
plugins: {
scene: [
{
key: 'MatterGravityFixPlugin',
plugin: MatterGravityFixPlugin,
mapping: 'matterGravityFix',
start: true,
},
],
},
};
/////////////////////////////////////////////////////////////////////////////////////////
Now, the custom plugin will apply the gravity fix you provided when the game starts.

[Dercetech]

const Matter = Phaser.Physics.Matter.Matter;

this line fails to pass tslint in my environment... any idea why Matter.Matter wouldn't ?

I have to force the following:

const Matter = (Phaser.Physics.Matter as any).Matter;

That being said, great fix. Thanks!

[photonstorm]

Thank you for submitting this issue. We have fixed this and the fix 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.