moveProxy method

@override bool moveProxy(int proxyId, AABB aabb, Vector2 displacement)

Move a proxy with a swepted AABB. If the proxy has moved outside of its fattened AABB, then the proxy is removed from the tree and re-inserted. Otherwise the function returns immediately. It returns true if the proxy was re-inserted.

Implementation

@override
bool moveProxy(int proxyId, AABB aabb, Vector2 displacement) {
  assert(aabb.isValid());
  assert(0 <= proxyId && proxyId < _nodeCapacity);
  final node = _nodes[proxyId];
  assert(node.child1 == null);

  final nodeAABB = node.aabb;
  // if (nodeAABB.contains(aabb)) {
  if ((nodeAABB.lowerBound.x <= aabb.lowerBound.x) &&
      (nodeAABB.lowerBound.y <= aabb.lowerBound.y) &&
      (aabb.upperBound.x <= nodeAABB.upperBound.x) &&
      (aabb.upperBound.y <= nodeAABB.upperBound.y)) {
    return false;
  }

  _removeLeaf(node);

  // Extend AABB
  final lowerBound = nodeAABB.lowerBound;
  final upperBound = nodeAABB.upperBound;
  lowerBound.x = aabb.lowerBound.x - settings.aabbExtension;
  lowerBound.y = aabb.lowerBound.y - settings.aabbExtension;
  upperBound.x = aabb.upperBound.x + settings.aabbExtension;
  upperBound.y = aabb.upperBound.y + settings.aabbExtension;

  // Predict AABB displacement.
  final dx = displacement.x * settings.aabbMultiplier;
  final dy = displacement.y * settings.aabbMultiplier;
  if (dx < 0.0) {
    lowerBound.x += dx;
  } else {
    upperBound.x += dx;
  }

  if (dy < 0.0) {
    lowerBound.y += dy;
  } else {
    upperBound.y += dy;
  }

  _insertLeaf(proxyId);
  return true;
}