Function ExternalRoomVisible

Descent3/terrainrender.cpp:1012–1032

Returns true if the external room is in the view cone Else returns false

// Returns true if the external room is in the view cone
// Else returns false
bool ExternalRoomVisible(room *rp, vector *center, float *zdist) {
  ASSERT(rp->flags & RF_EXTERNAL);
  g3Point pnt;
  uint8_t ccode;

  vector corners[8];
  g3_RotatePoint(&pnt, center);
  *zdist = pnt.p3_z;
  MakePointsFromMinMax(corners, &rp->min_xyz, &rp->max_xyz);
  uint8_t andbyte = 0xff;
  for (int t = 0; t < 8; t++) {
    g3_RotatePoint(&pnt, &corners[t]);
    ccode = g3_CodePoint(&pnt);
    if (!ccode)
      return true;
    andbyte &= ccode;
  }
  if (andbyte)
    return false;
  return true;
}
// Render all the rooms out on the terrain for this frame
void RenderTerrainRooms() {
  object *obj;