code: func MipmapLevel(det float32) int {
  	if math.IsNaN(float64(det)) {
  		panic("graphicsutil: det must be finite")
  	}
  	if det == 0 {
  		return -1
  	}
  
  	d := math.Abs(float64(det))
  	level := 0
  	for d < 0.25 {
  		level++
  		d *= 4
  	}
  	return level
  }
docs: // MipmapLevel returns an appropriate mipmap level for the given determinant of a geometry matrix.
  //
  // MipmapLevel returns -1 if det is 0.
  //
  // MipmapLevel panics if det is NaN.