Child entity should inherit transform.coordPlane of parent

[mattjennings]

I think a child entity should inherit the coordPlane of its parent's transform.

Consider having a ScreenElement with children - currently, its children do not follow along with it (at least, not properly). If I set the coordPlane of the children to ex.CoordPlane.Screen, they do.

Steps to Reproduce

export default class Level1 extends ex.Scene {
  onInitialize() {
    const player = new ex.Actor({
      x: 100,
      y: 100,
      width: 100,
      height: 100,
      color: ex.Color.Yellow,
      vel: ex.vec(50, 0),
    })
    this.add(player)

    this.camera.strategy.lockToActor(player)

    const screenEl = new ex.ScreenElement({
      width: 100,
      height: 100,
      color: ex.Color.Red,
    })

    this.add(screenEl)

    screenEl.addChild(
      new ex.Label({
        text: 'hello',
        color: ex.Color.White,
        font: new ex.Font({
          size: 32,
        }),
      }),
    )
  }
}

CleanShot.2024-02-16.at.16.15.24.mp4

Expected Result

It's a bit hard to tell in the clip, but "hello" should be staying in position as a child of the red box screen element.

Actual Result

"hello" coordPlane is to the world instead of the Screen, so it moves off the camera.

Environment

• Excalibur versions: 0.28.7

Current Workaround

Manually setting the child's coordPlane to ex.CoordPlane.Screen

[eonarheim]

@mattjennings I agree, I think someone else ran into this and it produces unexpected results.

Going to label this a bug