void UpdateRoot(QuadtreeData <T> root)
{
_root = root;
if (!DontHaveChildren())
{
_upperRightChild.UpdateRoot(root);
_lowerRightChild.UpdateRoot(root);
_lowerLeftChild.UpdateRoot(root);
_upperLeftChild.UpdateRoot(root);
}
}
//向上生长
void UpwardGrouth(Vector2 leafPosition)
{
/*
* 先要明确什么情况下向哪个方向生长
*
* 以原范围中心点为基准点
* 如果叶子在基准点左，向左生长，如果在基准点位置或右边，向右生长
* 如果叶子在基准点下方，向下生长，如果在基准点位置或上方，向上生长
*/
Vector2 growthDirection = leafPosition - _field.center; //方向，正数是上和右
float newTop = growthDirection.y >= 0 ? _field.top + _field.height : _field.top;
float newRight = growthDirection.x >= 0 ? _field.right + _field.width : _field.right;
float newBottom = growthDirection.y >= 0 ? _field.bottom : _field.bottom - _field.height;
float newLeft = growthDirection.x >= 0 ? _field.left : _field.left - _field.width;
float newXCenter = growthDirection.x >= 0 ? _field.right : _field.left;
float newYCenter = growthDirection.y >= 0 ? _field.top : _field.bottom;
QuadtreeData <T> newRoot = new QuadtreeData <T>(newTop, newRight, newBottom, newLeft, _maxLeafsNumber, _minSideLength); //新根节点
//右上节点，需要存入的情况是向左下方生长，即 x < 0 && y < 0
if (growthDirection.x >= 0 || growthDirection.y >= 0) //只要不满足向左下方生长的条件就用创建
{
newRoot._upperRightChild = new QuadtreeData <T>(newTop, newRight, newYCenter, newXCenter, _maxLeafsNumber, _minSideLength, newRoot, newRoot);
}
else
{
newRoot._upperRightChild = this;
}
//右下节点，需要存入的情况是向左上方生长，即 x <0 && y >= 0
if (growthDirection.x >= 0 || growthDirection.y < 0)
{
newRoot._lowerRightChild = new QuadtreeData <T>(newYCenter, newRight, newBottom, newXCenter, _maxLeafsNumber, _minSideLength, newRoot, newRoot);
}
else
{
newRoot._lowerRightChild = this;
}
//左下节点，需要存入的情况是向右上方生长，即 x >= 0 && y >= 0
if (growthDirection.x < 0 || growthDirection.y < 0)
{
newRoot._lowerLeftChild = new QuadtreeData <T>(newYCenter, newXCenter, newBottom, newLeft, _maxLeafsNumber, _minSideLength, newRoot, newRoot);
}
else
{
newRoot._lowerLeftChild = this;
}
//左上节点，需要存入的情况是向右下方生长，即 x >= 0 && y < 0
if (growthDirection.x < 0 || growthDirection.y >= 0)
{
newRoot._upperLeftChild = new QuadtreeData <T>(newTop, newXCenter, newYCenter, newLeft, _maxLeafsNumber, _minSideLength, newRoot, newRoot);
}
else
{
newRoot._upperLeftChild = this;
}
_parent = newRoot; //因为每次向上生长都是由现在的根节点调用的，新的根节点生长完成后旧的根节点的父节点就是新的根节点
newRoot.UpdateRoot(newRoot);
}