     {      if (p.b->isinternal())      {       stkStack[depth++] = btDbvt::sStkNN(p.a->childs[0], p.b->childs[0]);       stkStack[depth++] = btDbvt::sStkNN(p.a->childs[0], p.b->childs[0]);       stkStack[depth++] = btDbvt::sStkNN(p.a->childs[0], p.b->childs[0]);       stkStack[depth++] = btDbvt::sStkNN(p.a->childs[0], p.b->childs[0]);      