feat: YSortComponent

[mattjennings]

===:clipboard: PR Checklist :clipboard:===

• 📌 issue exists in github for these changes
• 🔬 existing tests still pass
• 🙈 code conforms to the style guide
• 📐 new tests written and passing / old tests updated with new scenario(s)
• 📄 changelog entry added (or not needed)

==================

Changes:

• YSortComponent that adjusts z-index based on its global Y position. This can be used on an
  Actor with the new ySort configuration in the constructor, or added as a component to an Entity.

  new ex.Actor({
    ySort: true,
    // or
    ySort: {
      offset: 0, // apply an offset to the resulting z-index
      order: 1 // 1 will add the pos.y to the z-index, -1 will subtract it
    }
  });
  
  // or
  entity.addComponent(
    new ex.YSortComponent({
      offset: 0,
      order: 1
    })
  );

CleanShot.2024-05-11.at.18.09.35.mp4

Open to any feedback or suggestions on functionality / API.

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View logs

[eonarheim]

@mattjennings Looks completely reasonable to me, no notes! Let me know if you're ready to merge

[eonarheim]

We spoke offline, we are going to test this with some Tilemap use cases first before merging

[mattjennings]

After discussion on discord, we decided:

• Scene should have a config that will enable ysorting for all entities.
• YSortComponent should take optional min/max z values as a way to enable layering.

Further ideas from myself since discussion:

• The Scene config should only apply to entities that contain a YSortComponent
• YSortComponent is included in all actors by default, and uses the Scene's ySort config unless overridden. In other words, if it's enabled by Scene, then every Actor sorts.
• Caveat: would mean we need to add YSortComponent to tilemap plugins etc. May be easy to miss it when composing custom entities. Maybe the YSort logic should be in the TransformComponent?

class MyScene extends ex.Scene {
  constructor() {
      super({ 
        ySort: true,
        // and/or ?
       ySort: { enabled: true, ...otherConfig }
      })
   }
}

class MyActor {
   constructor() {
      super({
          // ySort config defaults to scene's ySort
      })
   }
}