// a DirtyArea is used ingame to track rectangles on the visible map that need redrawing due to rubble and stuff
// this func is used only when initializing a scenario, and generating a random map

static void TacticalClass::ClearDirtyAreas() {
  int len = vec_DirtyAreas.Length;
  while(len) {
    --len;
    vec_DirtyAreas.Length = len;
    if(len <= 0) {
      break;
    }
    for(int idx = 0; idx < len; ++idx) {
      // this copies one DirtyArea from position x to position x - 1
      memcpy(&vec_DirtyAreas[idx], &vec_DirtyAreas[idx + 1], sizeof(DirtyArea));
    }
  }
}