Function smith_g1

tools/bloom-reference/src/main.rs:1332–1336

(n_dot_x: f32, alpha: f32)

}

fn smith_g1(n_dot_x: f32, alpha: f32) -> f32 {
    let a2 = alpha * alpha;
    let inner = ((1.0 - a2) * n_dot_x * n_dot_x + a2).sqrt();
    2.0 * n_dot_x / (n_dot_x + inner + 1e-6)
}

// ============================================================
// Environment (HDR equirectangular map + procedural fallback)