feat: Possibility to ignore hitboxes for ray casting

[spydon]

Description

A lot of the time it is useful to be able to ignore certain hitboxes, if you are for example casting rays from within the hitbox of one of your components. This PR adds this functionality to raycast, raycastAll and raytrace.

Checklist

• The title of my PR starts with a Conventional Commit prefix (fix:, feat:, docs: etc).
• I have read the Contributor Guide and followed the process outlined for submitting PRs.
• I have updated/added tests for ALL new/updated/fixed functionality.
• I have updated/added relevant documentation in docs and added dartdoc comments with ///.
• I have updated/added relevant examples in examples.

Breaking Change

• No, this is not a breaking change.

Related Issues

[ufrshubham]

Did some quick testing and found this to be working as expect. But also found an issues when using CircleHitboxes. It seems that if I cast a ray from inside a circular hitbox, it automatically ignores that hitbox. Here is an example code:

class RayCastGame extends FlameGame with HasCollisionDetection {
  RaycastResult<ShapeHitbox>? result;
  late ShapeHitbox shapeHitbox1;
  late ShapeHitbox shapeHitbox2;

  @override
  Future<void>? onLoad() {
    debugMode = true;
    add(
      CircleComponent(
        radius: 20,
        position: size / 2,
        anchor: Anchor.center,
        paint: Paint()..color = Colors.red,
      )..add(
          shapeHitbox1 = CircleHitbox(), // Left 
          //shapeHitbox1 = RectangleHitbox(), // Right
        ),
    );

    add(
      CircleComponent(
        radius: 20,
        position: Vector2(size.x / 2, 30),
        anchor: Anchor.center,
        paint: Paint()..color = Colors.blue,
      )..add(
          shapeHitbox2 = CircleHitbox(),
        ),
    );

    return super.onLoad();
  }

  @override
  void update(double dt) {
    final ray = Ray2(
      origin: size / 2,
      direction: Vector2(0, -1),
    );

    result = collisionDetection.raycast(
      ray,
    );

    super.update(dt);
  }

  @override
  void render(Canvas canvas) {
    if (result != null) {
      canvas.drawLine(
        (size / 2).toOffset(),
        (result!.intersectionPoint)!.toOffset(),
        Paint()
          ..color = Colors.yellow
          ..strokeWidth = 5,
      );
    }
    super.render(canvas);
  }
}

And here are the 2 outputs when using hitbox for red circle as CircleHitbox and RectangleHitbox. Left one uses a circular hitbox and right one uses rectangular hitbox. For some reason the ray cast passes through the hitbox of red circle in first example.

Let me know if this should be reported as a separate issue. Hope that I am not missing something very obvious.

[spydon]

Thanks @ufrshubham for checking! This behaviour seems unrelated to this PR, maybe you could just copy your comment and open an issue with it?
Strange that this faulty behaviour doesn't present itself in the examples on https//examples.flame-engine.org...