CheckBoneFlip()

Flips the bone’s rotation if either of the provided scale axes is negative (but not both).

This is the standard method of ‘flipping’ sprites, hence it uses an arbitrary scale rather than the bone’s own.

function CheckBoneFlip(bone: Bone, scale: Vec2) {
    bool both = scale.x < 0. && scale.y < 0.
    bool either = scale.x < 0. || scale.y < 0.
    if(either && !both) {
        bone.rot = -bone.rot
    }
}