//Method that creates the 8 children of this node. After creating them, it empties its own List of items-
private bool split()
{
float half = halfSpaceLength / 2f;
if (half >= minimumSize)
{
for (int y = 0; y < 2; y++)
{
for (int z = 0; z < 2; z++)
{
for (int x = 0; x < 2; x++)
{
Vector3 childCenter = new Vector3(centerSpace.x + half * Mathf.Pow(-1f, x),
centerSpace.y + half * Mathf.Pow(-1f, y),
centerSpace.z + half * Mathf.Pow(-1f, z));
_children [4 * y + 2 * z + x] = new octreeNode(this, new List <octreeItem>(nodeElements), half, childCenter, "node");
}
}
}
return(true);
}
else
{
return(false);
}
}
//Constructor-
public octreeNode(octreeNode parent, List <octreeItem> potentialItems, float halfLength, Vector3 centerPos, string name)
{
this.parent = parent;
this.centerSpace = centerPos;
this.halfSpaceLength = halfLength;
this.name = name + "(" + id++ + ")"; //Only for debugging-
for (int i = 0; i < potentialItems.Count; i++)
{
processItem(potentialItems[i]);
}
//Graphic representation of the space-
drawNodeSpace();
}
//Alternative to push method proposed below:
private void pushItem(octreeItem item)
{
//If the item belongs to this node's elements, then it will not be evaluated:
if (!nodeElements.Contains(item))
{
//If the item has an owner (meaning he is being modified, not created):
if (item.ownerNodes.Count > 0)
{
//If the item's owner is different from this node (caused by items moved or node split)
if (!ReferenceEquals(this, item.ownerNodes [0]))
{
//You get the previous owner reference:
octreeNode prevOwner = item.ownerNodes [0];
prevOwner.nodeElements.Remove(item);
item.ownerNodes [0] = this;
this.nodeElements.Add(item);
//If the previous owner was not root, then you have to check wether his parent should merge his children back together:
//If the previous owner is the parent of this node, it does not enter here since it means it just split:
//Later, a bool could be used to know when we want to dinamically update the tree:
while (prevOwner.parent != null && !ReferenceEquals(this.parent, prevOwner)) //if (prevOwner.parent != null && !ReferenceEquals(this.parent, prevOwner))**##
{
//We get the parent node of the previous owner, which might get terminated:
octreeNode prevOwnerParent = prevOwner.parent;
List <octreeItem> tempElementsList = new List <octreeItem> ();
int totalCount = 0;
for (int i = 0; i < 8; i++)
{
octreeNode child = prevOwnerParent.children [i];
totalCount += child.nodeElements.Count;
tempElementsList.AddRange(child.nodeElements);
}
//Here, the prevOwnerParent destroy his children:
if (totalCount <= maxNumberOfElements)
{
for (int i = 0; i < 8; i++)
{
GameObject.Destroy(prevOwnerParent.children [i].obj);
prevOwnerParent.children [i] = null;
}
//Every item which pointed to these destroyed child nodes must now point to their parent (new owner):
for (int i = 0; i < tempElementsList.Count; i++)
{
tempElementsList [i].ownerNodes [0] = prevOwnerParent;
prevOwnerParent.nodeElements.Add(tempElementsList[i]);
}
}
//Now, we should set up the params for the next iteration:
prevOwner = prevOwnerParent; //Only when using the while()-**##
}
}
}
//If the item doesn't have an owner, he must be entering the octree for the first time:
else
{
item.ownerNodes.Add(this);
this.nodeElements.Add(item);
}
}
//If after adding the element the node is overloaded, it has to split and then empty his list:
if (nodeElements.Count > maxNumberOfElements)
{
if (split())
{
nodeElements.Clear();
}
}
}
