/// <summary>
/// Finds and returns the node inside 'nodes' which is closest to 'node'.
/// </summary>
private SphereTreeNode <T> FindClosestNode(List <SphereTreeNode <T> > nodes, SphereTreeNode <T> node)
{
float minDistanceSq = float.MaxValue;
SphereTreeNode <T> closestNode = null;
// We will choose the node whose center is closest to 'node'
foreach (SphereTreeNode <T> potentialNode in nodes)
{
// Calculate the squared distance between the node centers
float distanceBetweenNodesSq = potentialNode.GetDistanceBetweenCentersSq(node);
if (distanceBetweenNodesSq < minDistanceSq)
{
// Smaller than what we have so far?
minDistanceSq = distanceBetweenNodesSq;
closestNode = potentialNode;
// If we somehow managed to find a node which has the same position as 'node', we can exit
if (minDistanceSq == 0.0f)
{
return(closestNode);
}
}
}
return(closestNode);
}
/// <summary>
/// Recursive method which is used to detect which terminal nodes in the tree are intersected
/// by 'ray'. Information about the intersected nodes is stored inside 'terminalNodeHitInfo'.
/// </summary>
private void RaycastAllRecurse(Ray ray, SphereTreeNode <T> parentNode, List <SphereTreeNodeRayHit <T> > terminalNodeHitInfo)
{
// If the parent node is not hit by the ray, there is no need to go further
float t;
if (!parentNode.Sphere.Raycast(ray, out t))
{
return;
}
else
{
// If the parent node was hit, we have 2 choices:
// a) if the node is a terminal node, we add it to the 'hitNodes' list and exit;
// b) if the node is a super-sphere, we will recurse for eacoh if its children.
if (parentNode.IsTerminal)
{
terminalNodeHitInfo.Add(new SphereTreeNodeRayHit <T>(ray, t, parentNode));
return;
}
else
{
// Recurse for each child node
List <SphereTreeNode <T> > childNodes = parentNode.Children;
foreach (SphereTreeNode <T> childNode in childNodes)
{
RaycastAllRecurse(ray, childNode, terminalNodeHitInfo);
}
}
}
}
/// <summary>
/// Recursive method which is used to step down the tree hierarchy collecting all terminal nodes
/// which are overlapped by the specified box.
/// </summary>
private void OverlapBoxRecurse(OrientedBox box, SphereTreeNode <T> parentNode, List <SphereTreeNode <T> > overlappedTerminalNodes)
{
// If the parent is not overlapped there is no need to go any further
if (!parentNode.Sphere.OverlapsFullyOrPartially(box))
{
return;
}
else
{
// If this is a terminal node, add it to the output list and return
if (parentNode.IsTerminal)
{
overlappedTerminalNodes.Add(parentNode);
return;
}
else
{
// Recurs for each child node
List <SphereTreeNode <T> > childNodes = parentNode.Children;
foreach (SphereTreeNode <T> childNode in childNodes)
{
OverlapBoxRecurse(box, childNode, overlappedTerminalNodes);
}
}
}
}
/// <summary>
/// The client code must call this function during each frame update in order
/// to ensure that any pending node updates are performed.
/// </summary>
public void PerformPendingUpdates()
{
// First, ensure that all nodes are recomputed accordingly
while (_nodesPendingRecomputation.Count != 0)
{
SphereTreeNode <T> node = _nodesPendingRecomputation.Dequeue();
// Note: If the node has any children left, we will recompute its volume. Otherwise,
// we will remove the node from the tree.
if (node.HasChildren)
{
node.RecomputeCenterAndRadius();
}
else
{
RemoveNode(node);
}
}
// At this point, all super sphere nodes have had their volume updated accordingly.
// In the next step, we will integrate any necessary terminal nodes.
while (_terminalNodesPendingIntegration.Count != 0)
{
SphereTreeNode <T> node = _terminalNodesPendingIntegration.Dequeue();
IntegrateTerminalNode(node);
}
}
/// <summary>
/// Removes the specified node from the tree.
/// </summary>
public void RemoveNode(SphereTreeNode <T> node)
{
// If the node is not the root node and if it has a parent...
if (!node.IsRoot && node.Parent != null)
{
// Remove the node from its parent
SphereTreeNode <T> parentNode = node.Parent;
parentNode.RemoveChild(node);
// Move up the hierarhcy and remove all parents which don't have any children any more.
// Note: We will always stop at the root node. The root node is allowed to exist even
// if it has no children.
while (parentNode.Parent != null && parentNode.HasNoChildren && !parentNode.IsRoot)
{
SphereTreeNode <T> newParent = parentNode.Parent;
newParent.RemoveChild(parentNode);
parentNode = newParent;
}
// At this point 'parentNode' references the deepest parent which has at least one child.
// Because we have removed children from it, its volume must be recalculated, so we add
// it to the recomputation queue.
// Note: Even if this function was called from 'PerformPendingUpdates' we still get correct
// results because the node will be added to the recomputation queue and it will be
// processed inside the recomputation 'while' loop from where this method is called.
AddNodeToRecomputationQueue(parentNode);
}
}
/// <summary>
/// Registers the specified object with the tree.
/// </summary>
private bool RegisterGameObject(GameObject gameObject)
{
if (!CanGameObjectBeRegisteredWithTree(gameObject))
{
return(false);
}
// Build the object's sphere
Box objectWorldBox = gameObject.GetWorldBox();
Sphere3D objectSphere = objectWorldBox.GetEncapsulatingSphere();
// Add the object as a terminal node. Also store the node in the dictionary so that we can
// use it when it's needed.
SphereTreeNode <GameObject> objectNode = _sphereTree.AddTerminalNode(objectSphere, gameObject);
_gameObjectToNode.Add(gameObject, objectNode);
#if !USE_TRANSFORM_HAS_CHANGED
_gameObjectToTransformData.Add(gameObject, GetGameObjectTransformData(gameObject));
#endif
// If it is a mesh object, start silent building the mesh
if (gameObject.HasMesh())
{
EditorMesh editorMesh = EditorMeshDatabase.Instance.CreateEditorMesh(gameObject.GetMesh());
if (editorMesh != null)
{
EditorMeshDatabase.Instance.AddMeshToSilentBuild(editorMesh);
}
}
EditorCamera.Instance.AdjustObjectVisibility(gameObject);
return(true);
}
/// <summary>
/// Creates the root node of the tree.
/// </summary>
private void CreateRootNode()
{
// Create the root node with some sensible default values. It doesn't really matter what
// initial size the root node has. It will grow as needed when new nodes are added to the
// tree.
_rootNode = new SphereTreeNode <T>(Vector3.zero, 10.0f, this);
_rootNode.SetFlag(SphereTreeNodeFlags.Root | SphereTreeNodeFlags.SuperSphere);
}
/// <summary>
/// Integrates the specified node into the tree hierarchy. Integrating a nod means placing it
/// inside the tree hierarchy in the correct spot. Because it is a terminal node, the method
/// will have to search for the correct super-sphere node which can act as a parent of this node.
/// </summary>
private void IntegrateTerminalNode(SphereTreeNode <T> nodeToIntegrate)
{
// Start a recursive process from the root of the hierarchy. After the integration
// is finished, we will clear the node's integration flag because it no loger needs
// to be integrated.
IntegrateTerminalNodeRecurse(nodeToIntegrate, _rootNode);
nodeToIntegrate.ClearFlag(SphereTreeNodeFlags.MustIntegrate);
}
/// <summary>
/// Recursive function which renders the specified node in the scene view and then
/// steps down the hierarchy for each child of the node.
/// </summary>
private void RenderGizmosDebugRecurse(SphereTreeNode <T> node)
{
// Draw the sphere for the specified node and then recurse for each child node
Gizmos.DrawSphere(node.Sphere.Center, node.Sphere.Radius);
foreach (var child in node.Children)
{
RenderGizmosDebugRecurse(child);
}
}
public void RemoveChild(SphereTreeNode <T> child)
{
int indexOfChild = _children.FindIndex(item => item == child);
if (indexOfChild >= 0)
{
_children.RemoveAt(indexOfChild);
child._parent = null;
}
}
/// <summary>
/// Adds a terminal node to the tree.
/// </summary>
/// <remarks>
/// The function does not integrate the node inside the sphere hierarchy. It
/// will only add it to the integration pending queue. The actual integration
/// process will be performed inside 'PerformPendingUpdates'.
/// </remarks>
/// <param name="sphere">
/// The node's sphere.
/// </param>
/// <param name="data">
/// The node's data.
/// </param>
/// <returns>
/// The node which was added to the tree.
/// </returns>
public SphereTreeNode <T> AddTerminalNode(Sphere3D sphere, T data)
{
// Create a new node and mark it as terminal
var newTerminalNode = new SphereTreeNode <T>(sphere, this, data);
newTerminalNode.SetFlag(SphereTreeNodeFlags.Terminal);
// Add the node to the integration queue
AddNodeToIntegrationQueue(newTerminalNode);
return(newTerminalNode);
}
public void EncapsulateChildNode(SphereTreeNode <T> node)
{
SphereTreeNode <T> currentParent = this;
SphereTreeNode <T> currentChild = node;
while (currentParent != null && !currentParent.FullyContains(currentChild))
{
currentParent.Encapsulate(currentChild);
currentChild = currentParent;
currentParent = currentParent.Parent;
}
}
/// <summary>
/// This is a recursive method which is responsible for integration the specified
/// node inside the tree.
/// </summary>
private void IntegrateTerminalNodeRecurse(SphereTreeNode <T> nodeToIntegrate, SphereTreeNode <T> parentNode)
{
// If this node still has room for children, we will add the integration node here. This 'if' statement
// will also handle the special case in which only the root node currently exists inside the tree.
if (parentNode.NumberOfChildren < _numberOfChildNodesPerNode)
{
// Add the node as a child of the parent node and ensure that the root node encapsulates it
parentNode.AddChild(nodeToIntegrate);
//parentNode.EncapsulateChildNode(nodeToIntegrate);
parentNode.RecomputeCenterAndRadius();
}
else
{
// If there is no more room, we will proceed by choosing one of the parent's children which
// is closest to the node that we want to integrate. We choose the closest node because when
// the node will be added as a child of it, we want the parent to grow as little as possible.
List <SphereTreeNode <T> > children = parentNode.Children;
SphereTreeNode <T> closestChild = FindClosestNode(children, nodeToIntegrate);
if (closestChild == null)
{
return;
}
// If the closest child is not a terminal node, recurse.
if (!closestChild.IsTerminal)
{
IntegrateTerminalNodeRecurse(nodeToIntegrate, closestChild);
}
else
{
SphereTreeNode <T> newParentNode = new SphereTreeNode <T>(closestChild.Sphere, this, default(T));
newParentNode.SetFlag(SphereTreeNodeFlags.SuperSphere);
// Replace 'closestChild' with the new parent node and add both 'closestChild' and 'nodeToIntegrate' as children of it
parentNode.RemoveChild(closestChild);
parentNode.AddChild(newParentNode);
newParentNode.AddChild(nodeToIntegrate);
newParentNode.AddChild(closestChild);
// Encapsulate the children inside the new node
//newParentNode.EncapsulateChildNode(closestChild);
//newParentNode.EncapsulateChildNode(nodeToIntegrate);
// Ensure that the new node is fully contained inside the parent node
//parentNode.EncapsulateChildNode(newParentNode);
newParentNode.RecomputeCenterAndRadius();
parentNode.RecomputeCenterAndRadius();
}
}
}
/// <summary>
/// Adds the specified node to the integration queue.
/// </summary>
private void AddNodeToIntegrationQueue(SphereTreeNode <T> node)
{
// Only terminal, non-root nodes are allowed. We also have to ensure that
// the node hasn't already been added to the integration queue.
if (node.IsSuperSphere || node.IsRoot || node.MustIntegrate)
{
return;
}
if (node.IsTerminal)
{
node.SetFlag(SphereTreeNodeFlags.MustIntegrate);
_terminalNodesPendingIntegration.Enqueue(node);
}
}
/// <summary>
/// Recursive method which steps down the tree hierarchy and adds pairs of node-data/node to 'dictionary'.
/// When this method returns, all the terminal nodes and their data will be stored inside 'dictionary'.
/// </summary>
private void GetDataToTerminalNodeDictionaryRecurse(SphereTreeNode <T> parentNode, Dictionary <T, SphereTreeNode <T> > dictionary)
{
if (parentNode.IsTerminal)
{
dictionary.Add(parentNode.Data, parentNode);
}
else
{
List <SphereTreeNode <T> > children = parentNode.Children;
foreach (var child in children)
{
GetDataToTerminalNodeDictionaryRecurse(child, dictionary);
}
}
}
public void AddChild(SphereTreeNode <T> child)
{
if (ContainsChild(child))
{
return;
}
if (child.HasParent)
{
child.Parent.RemoveChild(child);
}
_children.Add(child);
child._parent = this;
}
/// <summary>
/// Handles the transform change for the specified object transform.
/// </summary>
private void HandleObjectTransformChange(Transform gameObjectTransform)
{
// Just ensure that the object is registered with the tree
GameObject gameObject = gameObjectTransform.gameObject;
if (!IsGameObjectRegistered(gameObject))
{
return;
}
// Store the object's node for easy access. We will need to instruct the
// tree to update this node as needed.
SphereTreeNode <GameObject> objectNode = _gameObjectToNode[gameObject];
// We will first have to detect what has changed. So we will compare the
// object's sphere as it is now with what was before.
bool updateCenter = false;
bool updateRadius = false;
Sphere3D previousSphere = objectNode.Sphere;
Sphere3D currentSphere = gameObject.GetWorldBox().GetEncapsulatingSphere();
// Detect what changed
if (previousSphere.Center != currentSphere.Center)
{
updateCenter = true;
}
if (previousSphere.Radius != currentSphere.Radius)
{
updateRadius = true;
}
// Call the appropriate node update method
if (updateCenter && updateRadius)
{
_sphereTree.UpdateTerminalNodeCenterAndRadius(objectNode, currentSphere.Center, currentSphere.Radius);
}
else if (updateCenter)
{
_sphereTree.UpdateTerminalNodeCenter(objectNode, currentSphere.Center);
}
else if (updateRadius)
{
_sphereTree.UpdateTerminalNodeRadius(objectNode, currentSphere.Radius);
}
EditorCamera.Instance.AdjustObjectVisibility(gameObject);
}
/// <summary>
/// This method is called when the sphere of a terminal node has been updated.
/// </summary>
private void OnTerminalNodeSphereUpdated(SphereTreeNode <T> terminalNode)
{
// If the node is already marked for reintegration, there is nothing left for us to do
if (terminalNode.MustIntegrate)
{
return;
}
// If the node is now outside of its parent, it may now be closer to another parent and associating
// it with that new parent may provide better space/volume savings. So we remove the node from its
// parent and add it to the integration queue so that it can be reintegrated. During the integration
// process, the algorithm may find a more optimal parent or the same one if a more optimal one doesn't
// exist.
// Note: We are only removing the child from its parent if it went outside of its parent volume. It may
// probably be a better idea to always check the surrounding parents and see if a more optimal one
// exists even if the node doesn't pierce its parent's skin. For the moment however, we will only
// remove the child from its parent if it pierced its skin.
SphereTreeNode <T> parentNode = terminalNode.Parent;
float distanceToParentNodeExitPoint = parentNode.GetDistanceToNodeExitPoint(terminalNode);
if (distanceToParentNodeExitPoint > parentNode.Radius)
{
// Note: It may be a good idea to check if the node contains only one child after removal. In that
// case the node itself can be remove and its child moved up the hierarchy. However, for the
// moment we'll keep things simple.
// Remove the child from its parent and add it to the integration queue. Adding it to
// the integration queue is necessary in order to ensure that it gets reassigned to
// the correct parrent based on its current position.
parentNode.RemoveChild(terminalNode);
AddNodeToIntegrationQueue(terminalNode);
}
// Whenever a terminal node is updated, it's parent must gave its volume recomputed. We always do this
// regardless of whether or not the node was removed from the parent or not.
AddNodeToRecomputationQueue(parentNode);
}
public void Encapsulate(SphereTreeNode <T> node)
{
_sphere = _sphere.Encapsulate(node.Sphere);
}
/// <summary>
/// Updates the radius of the specified terminal node.
/// </summary>
public void UpdateTerminalNodeRadius(SphereTreeNode <T> terminalNode, float newRadius)
{
terminalNode.Radius = newRadius;
OnTerminalNodeSphereUpdated(terminalNode);
}
/// <summary>
/// Updates the center of the specified terminal node.
/// </summary>
public void UpdateTerminalNodeCenter(SphereTreeNode <T> terminalNode, Vector3 newCenter)
{
terminalNode.Center = newCenter;
OnTerminalNodeSphereUpdated(terminalNode);
}
public float GetDistanceBetweenCentersSq(SphereTreeNode <T> node)
{
return(_sphere.GetDistanceBetweenCentersSq(node.Sphere));
}
public float GetDistanceToNodeExitPoint(SphereTreeNode <T> node)
{
return((Center - node.Center).magnitude + node.Radius);
}
/// <summary>
/// Updates the center and radius of the specified terminal node.
/// </summary>
public void UpdateTerminalNodeCenterAndRadius(SphereTreeNode <T> terminalNode, Vector3 newCenter, float newRadius)
{
terminalNode.Center = newCenter;
terminalNode.Radius = newRadius;
OnTerminalNodeSphereUpdated(terminalNode);
}
public bool ContainsChild(SphereTreeNode <T> child)
{
return(_children.Contains(child));
}
public SphereTreeNodeRayHit(Ray ray, float t, SphereTreeNode <T> hitNode)
{
_ray = ray;
_hitNode = hitNode;
_hitPoint = _ray.GetPoint(t);
}
public bool FullyContains(SphereTreeNode <T> node)
{
return(_sphere.FullyOverlaps(node.Sphere));
}
