/// <summary>
/// constructor
/// </summary>
public Node(int parentNodeId, REGION region, Box boundaryBox)
{
_Tl = null;
_Tr = null;
_Bl = null;
_Br = null;
_Region = region;
_NodeId = parentNodeId * 10 + (int)_Region;
_ListObject = new List<TileObject>();
//node root
if (parentNodeId == 0)
_BoundaryBox = boundaryBox;
else
{
switch (_Region)
{
case REGION.TOP_LEFT:
_BoundaryBox = new Box(
boundaryBox.X - boundaryBox.Width/4,
boundaryBox.Y + boundaryBox.Height/4,
boundaryBox.Width/2,
boundaryBox.Height/2
);
break;
case REGION.TOP_RIGHT:
_BoundaryBox = new Box(
boundaryBox.X + boundaryBox.Width / 4,
boundaryBox.Y + boundaryBox.Height / 4,
boundaryBox.Width / 2,
boundaryBox.Height / 2
);
break;
case REGION.BOT_LEFT:
_BoundaryBox = new Box(
boundaryBox.X - boundaryBox.Width / 4,
boundaryBox.Y - boundaryBox.Height / 4,
boundaryBox.Width / 2,
boundaryBox.Height / 2
);
break;
case REGION.BOT_RIGHT:
_BoundaryBox = new Box(
boundaryBox.X + boundaryBox.Width / 4,
boundaryBox.Y - boundaryBox.Height / 4,
boundaryBox.Width / 2,
boundaryBox.Height / 2
);
break;
}
}
}
/// <summary>
/// insert node
/// </summary>
public static void InsertNode(Node node, TileObject obj)
{
//if object doesn't belong to node, then return
if (!Box.IsIntersect(node.BoundaryBox, obj.MovementRangeBox))
return;
//if node covers all screenhight and screenwidth, then divide it into 4 subnodes
if (node.BoundaryBox.Width >= SCREEN_WIDTH + 6 && node.BoundaryBox.Height >= SCREEN_HEIGHT + 6)
{
if (node._Tl == null)
node._Tl = new Node(node._NodeId, REGION.TOP_LEFT, node.BoundaryBox);
if (node._Tr == null)
node._Tr = new Node(node._NodeId, REGION.TOP_RIGHT, node.BoundaryBox);
if (node._Bl == null)
node._Bl = new Node(node._NodeId, REGION.BOT_LEFT, node.BoundaryBox);
if (node._Br == null)
node._Br = new Node(node._NodeId, REGION.BOT_RIGHT, node.BoundaryBox);
int left, right, top, bot;
left = obj.MovementRangeBox.X - obj.MovementRangeBox.Width / 2;
right = obj.MovementRangeBox.X + obj.MovementRangeBox.Width / 2;
top = obj.MovementRangeBox.Y + obj.MovementRangeBox.Height / 2;
bot = obj.MovementRangeBox.Y - obj.MovementRangeBox.Height / 2;
//if object places in two diagonals, then add it to node
if ((left <= node.BoundaryBox.X && right >= node.BoundaryBox.X)
|| (bot <= node.BoundaryBox.Y && top >= node.BoundaryBox.Y))
{
node.ListObject.Add(obj);
}
else
{
//insert each subnode to node
InsertNode(node._Tl, obj);
InsertNode(node._Tr, obj);
InsertNode(node._Bl, obj);
InsertNode(node._Br, obj);
}
}
//else if node just covers enough screenwidth or screenheight, then add obj to node
else
node.ListObject.Add(obj);
}