pub fn write_mat4(iso: &Iso3, out: &mut [f64])Expand description
Write iso as a row-major 4x4 f64 matrix.
Public because a binding needs to emit a single transform without paying
for a batch — the scalar path in docs/PHASE3.md §4.2, whose budget is
~200 ns end to end.
The rotation is expanded from the quaternion directly rather than through a
Mat3 type: the products below are shared between entries, so doing it in
one place lets the compiler keep every one of them in a register.