Function compose_attachment 

pub fn compose_attachment(
    bs: [f32; 3],
    bh: [f32; 3],
    bf: [f32; 3],
    bp: [f32; 3],
    off: &BoneXform,
) -> ([f32; 3], [f32; 3], [f32; 3], [f32; 3])

Compose a bone’s solved world transform with an attachment’s local_offset (VCL.6), giving the attachment’s world pose (s, h, f, p) — the basis columns + position to hand a sprite/clip instance.

(bs, bh, bf, bp) are the bone’s world basis columns + position (e.g. solve_kfa_limbs output limbs[bone].{s, h, f, p}); off is the attachment’s local TRS in the bone’s frame. The offset’s rotation + scale build the attachment’s local basis, then the bone basis maps it (and the offset translation) into world space. An identity off returns the bone transform unchanged.