//public void Subdivide(KdTreeNode node, AxisAlignedBox box, int depth, int prims) {
// // recycle used split list nodes
// _list = null;
// // determine split axis
// Vector3D s = box.Size;
// if ((s.X >= s.Y) && (s.X >= s.Z))
// node.Axis = 0;
// else if ((s.Y >= s.X) && (s.Y >= s.Z))
// node.Axis = 1;
// int axis = node.Axis;
// // make a list of the split position candidates
// ObjectList l = node.List;
// double p1, p2;
// double pos1 = box.Position[axis];
// double pos2 = box.Position[axis] + box.Size[axis];
// bool[] pright = new bool[prims];
// double[] eleft = new double[prims];
// double[] eright = new double[prims];
// Primitive[] parray = new Primitive[prims];
// int aidx = 0;
// while (l != null) {
// parray[aidx] = l.Primitive;
// Primitive p = parray[aidx];
// pright[aidx] = true;
// p.CalculateRange(ref eleft[aidx], ref eright[aidx], axis);
// aidx++;
// if (p.Type == PrimitiveType.Sphere) {
// p1 = p.Center[axis] - p.Radius;
// p2 = p.Center[axis] + p.Radius;
// if ((p1 >= pos1) && (p1 <= pos2)) InsertSplitPos( p1 );
// if ((p2 >= pos1) && (p2 <= pos2)) InsertSplitPos( p2 );
// }
// else {
// for (int i = 0; i < 3; i++ ) {
// p1 = p.GetVertex(i).Position[axis];
// if ((p1 >= pos1) && (p1 <= pos2)) InsertSplitPos( p1 );
// }
// }
// l = l.Next;
// }
// // determine n1count / n2count for each split position
// AxisAlignedBox b1 = null, b2 = null, b3, b4;
// b3 = box;
// b4 = box;
// SplitList splist = _list;
// double b3p1 = b3.Position[axis];
// double b4p2 = b4.Position[axis] + b4.Size[axis];
// while (splist != null) {
// b4.Position[axis] = splist.SplitPos;
// b4.Size[axis] = pos2 - splist.SplitPos;
// b3.Size[axis] = splist.SplitPos - pos1;
// double b3p2 = b3.Position[axis] + b3.Size[axis];
// double b4p1 = b4.Position[axis];
// for (int i = 0; i < prims; i++) {
// if (pright[i]) {
// Primitive p = parray[i];
// if ((eleft[i] <= b3p2) && (eright[i] >= b3p1))
// if (p.IntersectBox(b3))
// splist.N1Count++;
// if ((eleft[i] <= b4p2) && (eright[i] >= b4p1))
// if (p.IntersectBox(b4))
// splist.N2Count++;
// else
// pright[i] = false;
// }
// else
// splist.N1Count++;
// }
// splist = splist.Next;
// }
// // calculate surface area for current node
// double SAV = 0.5f / (box.W * box.D + box.W * box.H + box.D * box.H);
// // calculate cost for not splitting
// double Cleaf = prims * 1.0f;
// // determine optimal split plane position
// splist = _list;
// double lowcost = 10000;
// double bestpos = 0;
// while (splist != null) {
// // calculate child node extends
// b4.Position[axis] = splist.SplitPos;
// b4.Size[axis] = pos2 - splist.SplitPos;
// b3.Size[axis] = splist.SplitPos - pos1;
// // calculate child node cost
// double SA1 = 2 * (b3.W * b3.D + b3.W * b3.H + b3.D * b3.H);
// double SA2 = 2 * (b4.W * b4.D + b4.W * b4.H + b4.D * b4.H);
// double splitcost = 0.3f + 1.0f * (SA1 * SAV * splist.N1Count + SA2 * SAV * splist.N2Count);
// // update best cost tracking variables
// if (splitcost < lowcost) {
// lowcost = splitcost;
// bestpos = splist.SplitPos;
// b1 = b3;
// b2 = b4;
// }
// splist = splist.Next;
// }
// if (lowcost > Cleaf)
// return;
// node.SplitPosition = bestpos;
// // construct child nodes
// KdTreeNode tmpLeft = new KdTreeNode();
// KdTreeNode tmpRight = new KdTreeNode();
// int n1count = 0, n2count = 0, total = 0;
// // assign primitives to both sides
// double b1p1 = b1.Position[axis];
// double b2p2 = b2.Position[axis] + b2.Size[axis];
// double b1p2 = b1.Position[axis] + b1.Size[axis];
// double b2p1 = b2.Position[axis];
// for ( int i = 0; i < prims; i++ ) {
// Primitive p = parray[i];
// total++;
// if (eleft[i] <= b1p2 && eright[i] >= b1p1) {
// if (p.IntersectBox(b1)) {
// tmpLeft.Add(p);
// n1count++;
// }
// }
// if (eleft[i] <= b2p2 && eright[i] >= b2p1) {
// if (p.IntersectBox(b2)) {
// tmpRight.Add(p);
// n2count++;
// }
// }
// }
// node.List = null;
// if (n1count > 0) node.Left = tmpLeft;
// if (n2count > 0) node.Right = tmpRight;
// if (depth < Constants.MaxTreeDepth) {
// if (n1count > 2) Subdivide(tmpLeft, b1, depth + 1, n1count);
// if (n2count > 2) Subdivide(tmpRight, b2, depth + 1, n2count);
// }
//}
public void Subdivide(KdTreeNode node, AxisAlignedBox box, int depth, int prims)
{
// recycle used split list nodes
_sortedList = null;
// determine split axis
Vector3D s = box.Size;
if ((s.X >= s.Y) && (s.X >= s.Z))
node.Axis = 0;
else if ((s.Y >= s.X) && (s.Y >= s.Z))
node.Axis = 1;
int axis = node.Axis;
// make a list of the split position candidates
ObjectList l = node.List;
double p1, p2;
double pos1 = box.Position[axis];
double pos2 = box.Position[axis] + box.Size[axis];
bool[] pright = new bool[prims];
double[] eleft = new double[prims];
double[] eright = new double[prims];
Primitive[] parray = new Primitive[prims];
int aidx = 0;
while (l != null) {
parray[aidx] = l.Primitive;
Primitive p = parray[aidx];
pright[aidx] = true;
p.CalculateRange(ref eleft[aidx], ref eright[aidx], axis);
aidx++;
if (p.Type == PrimitiveType.Sphere) {
p1 = p.Center[axis] - p.Radius;
p2 = p.Center[axis] + p.Radius;
if ((p1 >= pos1) && (p1 <= pos2)) InsertSplitPos(p1);
if ((p2 >= pos1) && (p2 <= pos2)) InsertSplitPos(p2);
}
else {
for (int i = 0; i < 3; i++) {
p1 = p.GetVertex(i).Position[axis];
if ((p1 >= pos1) && (p1 <= pos2)) InsertSplitPos(p1);
}
}
l = l.Next;
}
// determine n1count / n2count for each split position
AxisAlignedBox b1 = null, b2 = null, b3, b4;
b3 = box;
b4 = box;
double b3p1 = b3.Position[axis];
double b4p2 = b4.Position[axis] + b4.Size[axis];
if (_sortedList == null)
return;
foreach (KeyValuePair<double, SplitListItem> pair in _sortedList) {
SplitListItem spListItem = pair.Value;
b4.Position[axis] = spListItem.SplitPos;
b4.Size[axis] = pos2 - spListItem.SplitPos;
b3.Size[axis] = spListItem.SplitPos - pos1;
double b3p2 = b3.Position[axis] + b3.Size[axis];
double b4p1 = b4.Position[axis];
for (int i = 0; i < prims; i++) {
if (pright[i]) {
Primitive p = parray[i];
if ((eleft[i] <= b3p2) && (eright[i] >= b3p1))
if (p.IntersectBox(b3))
spListItem.N1Count++;
if ((eleft[i] <= b4p2) && (eright[i] >= b4p1))
if (p.IntersectBox(b4))
spListItem.N2Count++;
else
pright[i] = false;
}
else
spListItem.N1Count++;
}
}
// calculate surface area for current node
double SAV = 0.5f / (box.W * box.D + box.W * box.H + box.D * box.H);
// calculate cost for not splitting
double Cleaf = prims * 1.0f;
// determine optimal split plane position
double lowcost = 10000;
double bestpos = 0;
foreach (KeyValuePair<double, SplitListItem> pair in _sortedList) {
SplitListItem spListItem = pair.Value;
// calculate child node extends
b4.Position[axis] = spListItem.SplitPos;
b4.Size[axis] = pos2 - spListItem.SplitPos;
b3.Size[axis] = spListItem.SplitPos - pos1;
// calculate child node cost
double SA1 = 2 * (b3.W * b3.D + b3.W * b3.H + b3.D * b3.H);
double SA2 = 2 * (b4.W * b4.D + b4.W * b4.H + b4.D * b4.H);
double splitcost = 0.3f + 1.0f * (SA1 * SAV * spListItem.N1Count + SA2 * SAV * spListItem.N2Count);
// update best cost tracking variables
if (splitcost < lowcost) {
lowcost = splitcost;
bestpos = spListItem.SplitPos;
b1 = b3;
b2 = b4;
}
}
if (lowcost > Cleaf)
return;
node.SplitPosition = bestpos;
// construct child nodes
KdTreeNode tmpLeft = new KdTreeNode();
KdTreeNode tmpRight = new KdTreeNode();
int n1count = 0, n2count = 0, total = 0;
// assign primitives to both sides
double b1p1 = b1.Position[axis];
double b2p2 = b2.Position[axis] + b2.Size[axis];
double b1p2 = b1.Position[axis] + b1.Size[axis];
double b2p1 = b2.Position[axis];
for (int i = 0; i < prims; i++) {
Primitive p = parray[i];
total++;
if (eleft[i] <= b1p2 && eright[i] >= b1p1) {
if (p.IntersectBox(b1)) {
tmpLeft.Add(p);
n1count++;
}
}
if (eleft[i] <= b2p2 && eright[i] >= b2p1) {
if (p.IntersectBox(b2)) {
tmpRight.Add(p);
n2count++;
}
}
}
node.List = null;
if (n1count > 0) node.Left = tmpLeft;
if (n2count > 0) node.Right = tmpRight;
if (depth < Constants.MaxTreeDepth) {
if (n1count > 2) Subdivide(tmpLeft, b1, depth + 1, n1count);
if (n2count > 2) Subdivide(tmpRight, b2, depth + 1, n2count);
}
}
public KdTree()
{
Root = new KdTreeNode();
}
public static KdTreeNode makeInternal(Axis axis, int aboveChildIndex, float split)
{
KdTreeNode node = new KdTreeNode();
node.axis = axis;
node.splitPos = split;
node.aboveChild = aboveChildIndex;
return node;
}
public static KdTreeNode makeLeaf(int[] primIndices, int primIndicesBase, int numPrims)
{
KdTreeNode node = new KdTreeNode();
node.axis = Axis.none;
node.nPrimitives = numPrims;
if(numPrims == 0)
{
node.primitiveIndex = 0;
}
else if (numPrims == 1)
{
node.primitiveIndex = primIndices[primIndicesBase];
}
else
{
node.primitiveIndices = new int[numPrims];
Array.Copy(primIndices, primIndicesBase, node.primitiveIndices, 0, numPrims);
}
return node;
}
private void buildTree( int nodeNum, BBox nodeBounds, BBox[] allPrimBounds,
int[] primNums, int primNumsBase,
int nPrimitives, int depth, BoundEdge[][] edges,
int[] prims0,
int[] prims1, int prims1base,
int badRefines)
{
string indent = "".PadLeft(_maxDepth - depth);
if (nextFreeNode == nAllocedNodes)
{
int nAlloc = Math.Max(2*nAllocedNodes, 512);
KdTreeNode[] n = new KdTreeNode[nAlloc];
if (nAllocedNodes > 0)
Array.Copy(_nodes, n, nAllocedNodes);
_nodes = n;
nAllocedNodes = nAlloc;
}
++nextFreeNode;
// *** Termination: Stop recursion if we have few enough nodes or the max depth has been reached ***
if (nPrimitives <= _maxPrims || depth == 0)
{
_nodes[nodeNum] = KdTreeNode.makeLeaf(primNums, primNumsBase, nPrimitives);
#if DEBUG
Console.WriteLine(indent + _nodes[nodeNum]);
#endif
return;
}
// *** Not reached termination, so pick split plane and continue recursion ***
Axis bestAxis = Axis.none;
int bestOffset = -1;
float bestCost = float.PositiveInfinity;
float oldCost = iCost * (float)nPrimitives;
float totalSA = nodeBounds.surfaceArea();
float invTotalSA = 1.0f/totalSA;
Vector3 d = nodeBounds.pMax - nodeBounds.pMin;
Axis axis = nodeBounds.longestAxis(); // Start by checking the longest axis
int retries = 0;
retrySplit:
// Fill edge lists
for (int i=0; i<nPrimitives; i++)
{
int primIndex = primNums[primNumsBase + i];
BBox bbox = allPrimBounds[primIndex];
edges[(int)axis][2*i] = new BoundEdge( getAxisVal(bbox.pMin, axis), primIndex, true);
edges[(int)axis][2*i+1] = new BoundEdge(getAxisVal(bbox.pMax, axis), primIndex, false);
}
Array.Sort(edges[(int)axis], 0, 2*nPrimitives); // sort the edges of the first n primitives (2*n edges)
// Find the best split by checking cost of every possible split plane
int nBelow = 0, nAbove = nPrimitives;
for (int i=0; i<2*nPrimitives; i++)
{
if( edges[(int)axis][i].type == BoundType.End) --nAbove;
float edgeT = edges[(int)axis][i].t;
if (edgeT > getAxisVal(nodeBounds.pMin, axis) &&
edgeT < getAxisVal(nodeBounds.pMax, axis) )
{
// Compute split cost for the ith edge
Axis otherAxis0 = (Axis) ( ((int)axis+1) % 3);
Axis otherAxis1 = (Axis) ( ((int)axis+2) % 3);
float belowSA = 2* (getAxisVal(d, otherAxis0) * getAxisVal(d, otherAxis1) +
(edgeT - getAxisVal(nodeBounds.pMin, axis)) *
(getAxisVal(d, otherAxis0) + getAxisVal(d, otherAxis1)));
float aboveSA = 2*(getAxisVal(d, otherAxis0) * getAxisVal(d, otherAxis1) +
(getAxisVal(nodeBounds.pMax, axis) - edgeT) *
(getAxisVal(d, otherAxis0) + getAxisVal(d, otherAxis1)));
float pBelow = belowSA * invTotalSA;
float pAbove = aboveSA * invTotalSA;
float eb = (nAbove == 0 || nBelow == 0) ? emptyBonus : 0;
float cost = tCost + iCost * (1-eb) * (pBelow * nBelow + pAbove * nAbove);
// Save this split if it is better the previous split position
if(cost < bestCost)
{
bestCost = cost;
bestAxis = axis;
bestOffset = i;
}
}
if (edges[(int)axis][i].type == BoundType.Start) ++nBelow;
}
// Create a leaf node if no good split was found
if(bestAxis == Axis.none && retries < 2)
{
++retries;
axis = (Axis) ( ((int)axis+1) % 3);
goto retrySplit;
}
if (bestCost > oldCost) ++badRefines;
if (( bestCost > 4.0f * oldCost && nPrimitives < 16) || bestAxis == Axis.none || badRefines == 3)
{
_nodes[nodeNum] = KdTreeNode.makeLeaf(primNums, primNumsBase, nPrimitives);
#if DEBUG
Console.WriteLine(indent + _nodes[nodeNum] + " (split failure)");
#endif
return;
}
// Classifiy primitives with respect to split
int n0=0, n1=0;
for (int i=0; i<bestOffset; i++)
{
if(edges[(int)bestAxis][i].type == BoundType.Start)
prims0[n0++] = edges[(int)bestAxis][i].primNum;
}
for (int i=bestOffset+1; i<2*nPrimitives; i++)
{
if(edges[(int)bestAxis][i].type == BoundType.End)
prims1[prims1base + n1++] = edges[(int)bestAxis][i].primNum;
}
// Ititalize child nodes
float tsplit = edges[(int)bestAxis][bestOffset].t;
BBox bounds0 = nodeBounds, bounds1 = nodeBounds;
setAxisVal(ref bounds0.pMax, bestAxis, tsplit);
setAxisVal(ref bounds1.pMin, bestAxis, tsplit);
#if DEBUG
KdTreeNode testNode = KdTreeNode.makeInternal(bestAxis, nextFreeNode, tsplit);
int[] aboveIndices = new int[n1];
int[] belowIndices = new int[n0];
Array.Copy(prims0, belowIndices, n0);
Array.Copy(prims1, prims1base, aboveIndices, 0, n1);
Console.WriteLine(indent + testNode);
Console.WriteLine(indent + " Above: { " + String.Join(",", aboveIndices) + " }");
Console.WriteLine(indent + " Below: { " + String.Join(",", belowIndices) + " }");
#endif
buildTree(nodeNum+1, bounds0, allPrimBounds, prims0, 0, n0,
depth-1, edges, prims0, prims1, prims1base+nPrimitives-1, badRefines);
int aboveChild = nextFreeNode;
_nodes[nodeNum] = KdTreeNode.makeInternal(bestAxis, aboveChild, tsplit);
buildTree(aboveChild, bounds1, allPrimBounds, prims1, prims1base, n1,
depth-1, edges, prims0, prims1, prims1base+nPrimitives-1, badRefines);
}