@06wj Thank you for this PR.

But remember, this does not have to be a pixel-perfect calculation. It is OK for the bounding sphere to be conservative (i.e., oversized).

Perhaps something less-computational may be preferable...

@06wj For example, the sphere center can remain at zero. Maybe it is sufficient to simply increase (double?) the radius to account for the worst-case center offset.

By changing the center and rotation, the sprite may be far away from the origin, so it is difficult to achieve this function by simple calculation.
e.g.:

Now, I simplify this to the bounding sphere by calculating the center point and scaling.

By changing the center and rotation, the sprite may be far away from the origin

this.center = new Vector2( 0.5, 0.5 ); // should be between 0 and 1

See #12931.

Do we need to support centers outside of [ 0, 1 ]?

By changing the center and rotation, the sprite may be far away from the origin

this.center = new Vector2( 0.5, 0.5 ); // should be between 0 and 1

This restriction is not found in the documentation or in the code

Even if centers outside [ 0, 1 ] are supported, I think the PR only requires changing the sphere radius.

I think a sufficient radius can be computed given the center coordinates.

Added visualization of bounding spheres.