message: Don't use double arithmetic without need
  Can hurt performance on nvidia GPUs
diff: @@ -44,9 +44,9 @@ inline void unproject(
  )
  {
  vector<4, T> u(
  - T(2.0 * (win[0] - viewport[0]) / viewport[2] - 1.0),
  - T(2.0 * (win[1] - viewport[1]) / viewport[3] - 1.0),
  - T(2.0 * win[2] - 1.0),
  + T(2.0) * (win[0] - viewport[0]) / viewport[2] - T(1.0),
  + T(2.0) * (win[1] - viewport[1]) / viewport[3] - T(1.0),
  + T(2.0) * win[2] - T(1.0),
  T(1.0)
  );
  