appendChain method

void appendChain(int index1, int index2)

Implementation

void appendChain(int index1, int index2) {
  // index1 gets index2 appended to it, and index2 is removed
  var chain1 = chains[index1];
  var chain2 = chains[index2];
  var tail = chain1[chain1.length - 1];
  var tail2 = chain1[chain1.length - 2];
  var head = chain2[0];
  var head2 = chain2[1];

  if (Epsilon().pointsCollinear(tail2, tail, head)) {
    // tail isn't needed because it's directly between tail2 and head
    // tail2 ---tail---> head
    //if (buildLog != null) buildLog.chainRemoveTail(index1, tail);

    chain1.removeAt(chain1.length - 1);
    tail = tail2; // old tail is gone... new tail is what tail2 was
  }

  if (Epsilon().pointsCollinear(tail, head, head2)) {
    // head isn't needed because it's directly between tail and head2
    // tail ---head---> head2
    //  if (buildLog != null) buildLog.chainRemoveHead(index2, head);

    chain2.removeAt(0);
  }

  // if (buildLog != null) buildLog.chainJoin(index1, index2);

  chain1.addAll(chain2);
  chains.removeAt(index2);
}