Function ComputeFaceNormal

Descent3/room.cpp:795–806

Computes (fills in) the surface normal of a face. Finds the best normal on this face by checking all sets of three vertices IMPORTANT: The caller should really check the return value of this function Parameters: rp,facenum - the room and face to calculate the normal for Returns: true if the normal is ok false if the normal has a very small (pre-normalization) magnitude

// Returns:		true if the normal is ok
//					false if the normal has a very small (pre-normalization) magnitude
bool ComputeFaceNormal(room *rp, int facenum) {
  face *fp = &rp->faces[facenum];
  bool ok;

  ok = ComputeNormal(&fp->normal, fp->num_verts, fp->face_verts, rp->verts);

  if (!ok) {
    mprintf(1, "Warning: Low precision normal for room:face = %d:%d\n", ROOMNUM(rp), facenum);
  }

  return ok;
}

// Compute the surface normal from a list of vertices that determine a face
// Finds the best normal on this face by checking all sets of three vertices