public AABBTreeRayTestResult rayTest(AABBTree[] trees,
AABBTreeRay ray,
Func <AABBTree, AABBExternalNode, AABBTreeRay, double, double, AABBTreeRayTestResult> callback)
{
//
//
// we traverse both trees at once
// keeping a priority list of nodes to check next.
// TODO: possibly implement priority list more effeciently?
// binary heap probably too much overhead in typical case.
List <PriorityNode> priorityList = new List <PriorityNode>();
//current upperBound on distance to first intersection
//and current closest object properties
AABBTreeRayTestResult minimumResult = null;
var upperBound = ray.maxFactor;
for (int i = 0; i < trees.Length; i += 1)
{
AABBTree tree = trees[i];
if (tree.getNodeCount() != 0)
{
upperBound = processNode(tree, ray, 0, upperBound, callback, ref priorityList, ref minimumResult);
}
}
while (priorityList.Count != 0)
{
var nodeObj = priorityList.Last();
priorityList.RemoveAt(priorityList.Count - 1);
// A node inserted into priority list after this one may have
// moved the upper bound.
if (nodeObj.distance >= upperBound)
{
continue;
}
var nodeIndex = nodeObj.nodeIndex;
AABBTree tree = nodeObj.tree;
var nodes = tree.getNodes();
var node = nodes[nodeIndex];
var maxIndex = nodeIndex + node.escapeNodeOffset;
var childIndex = nodeIndex + 1;
do
{
upperBound = processNode(tree, ray, childIndex, upperBound, callback, ref priorityList, ref minimumResult);
childIndex += nodes[childIndex].escapeNodeOffset;
}while (childIndex < maxIndex);
}
return(minimumResult);
}
//if node is a leaf, intersect ray with shape
// otherwise insert node into priority list.
double processNode(AABBTree tree,
AABBTreeRay ray,
int nodeIndex,
double upperBound,
Func <AABBTree, AABBExternalNode, AABBTreeRay, double, double, AABBTreeRayTestResult> callback,
ref List <PriorityNode> priorityList,
ref AABBTreeRayTestResult minimumResult)
{
var nodes = tree.getNodes();
var node = nodes[nodeIndex];
var distance = distanceExtents(ray, node.extents, upperBound);
if (distance == null)
{
return(upperBound);
}
if (node.externalNode != null)
{
var result = callback(tree, node.externalNode, ray, distance.Value, upperBound);
if (result != null)
{
minimumResult = result;
upperBound = result.factor;
}
}
else
{
// TODO: change to binary search?
var length = priorityList.Count;
int i;
for (i = 0; i < length; i += 1)
{
var curObj = priorityList[i];
if (distance > curObj.distance)
{
break;
}
}
if (i >= length - 1)
{
//insert node at index i
priorityList.Add(new PriorityNode()
{
tree = tree,
nodeIndex = nodeIndex,
distance = distance.Value
});
}
else
{
//insert node at index i
priorityList.Insert(i + 1, new PriorityNode()
{
tree = tree,
nodeIndex = nodeIndex,
distance = distance.Value
});
}
}
return(upperBound);
}
