sdfRoundBox

fn sdfRoundBox(position: vec3<f32>, size: vec3<f32>, radius: f32) -> f32 {
  let q = abs(position) - size;
  return length(max(q, vec3<f32>(0.0))) + 
         min(max(q.x, max(q.y, q.z)), 0.0) - 
         radius;
}