Function cross

tools/imposter-baker/src/render.rs:449–451

(a: [f32; 3], b: [f32; 3])

    [v[0] / l, v[1] / l, v[2] / l]
}
fn cross(a: [f32; 3], b: [f32; 3]) -> [f32; 3] {
    [a[1] * b[2] - a[2] * b[1], a[2] * b[0] - a[0] * b[2], a[0] * b[1] - a[1] * b[0]]
}
fn dot3(a: [f32; 3], b: [f32; 3]) -> f32 { a[0]*b[0] + a[1]*b[1] + a[2]*b[2] }

fn look_at_rh(eye: [f32; 3], target: [f32; 3], up: [f32; 3]) -> [[f32; 4]; 4] {