public KdTree(Triangle[] triangles)
{
var minX = float.MaxValue;
var minY = float.MaxValue;
var minZ = float.MaxValue;
var maxX = float.MinValue;
var maxY = float.MinValue;
var maxZ = float.MinValue;
foreach (var triangle in triangles)
{
if (minX > triangle.BoxMin.X)
{
minX = triangle.BoxMin.X;
}
if (minY > triangle.BoxMin.Y)
{
minY = triangle.BoxMin.Y;
}
if (minZ > triangle.BoxMin.Z)
{
minZ = triangle.BoxMin.Z;
}
if (maxX < triangle.BoxMax.X)
{
maxX = triangle.BoxMax.X;
}
if (maxY < triangle.BoxMax.Y)
{
maxY = triangle.BoxMax.Y;
}
if (maxZ < triangle.BoxMax.Z)
{
maxZ = triangle.BoxMax.Z;
}
}
var boxMax = new Vector3(maxX, maxY, maxZ);
var boxMin = new Vector3(minX, minY, minZ);
HeadNode = new KdTreeNode(triangles, boxMin, boxMax, 1);
HeadNode.SplitNode();
}
public void SplitNode()
{
if (_splitted)
{
return;
}
_splitted = true;
if (Triangles == null || Triangles.Length == 0)
{
return;
}
CalculateElementsAmountInPossibleSubsections();
var lowestSah = float.MaxValue;
var boxSplits = CalculateSplits();
var parentSquare = CalculateSquare(BoxMin, BoxMax);
var bestBoxSplitIndex = 0;
var axis = 0;
int nLeft = 0, nRight = 0;
for (var i = 0; i < SplitsNumber; i++)
{
var xRightN = Triangles.Length - _xHigh[i];
var xLeftN = Triangles.Length - _xLow[i + 1];
var yRightN = Triangles.Length - _yHigh[i];
var yLeftN = Triangles.Length - _yLow[i + 1];
var zRightN = Triangles.Length - _zHigh[i];
var zLeftN = Triangles.Length - _zLow[i + 1];
var xLeftSquare = CalculateSquare(BoxMin, boxSplits[i].LBoxMax);
var xRightSquare = CalculateSquare(boxSplits[i].RBoxMin, BoxMax);
var yLeftSquare = CalculateSquare(BoxMin, boxSplits[i + SplitsNumber].LBoxMax);
var yRightSquare = CalculateSquare(boxSplits[i + SplitsNumber].RBoxMin, BoxMax);
var zLeftSquare = CalculateSquare(BoxMin, boxSplits[i + SplitsNumber * 2].LBoxMax);
var zRightSquare = CalculateSquare(boxSplits[i + SplitsNumber * 2].RBoxMin, BoxMax);
var tmpSah = CalculateSah(xLeftSquare, xLeftN, xRightSquare, xRightN, parentSquare);
if (tmpSah < lowestSah)
{
bestBoxSplitIndex = i;
lowestSah = tmpSah;
axis = 0;
nLeft = xLeftN;
nRight = xRightN;
}
tmpSah = CalculateSah(yLeftSquare, yLeftN, yRightSquare, yRightN, parentSquare);
if (tmpSah < lowestSah)
{
bestBoxSplitIndex = i + SplitsNumber;
lowestSah = tmpSah;
axis = 1;
nLeft = yLeftN;
nRight = yRightN;
}
tmpSah = CalculateSah(zLeftSquare, zLeftN, zRightSquare, zRightN, parentSquare);
if (tmpSah < lowestSah)
{
bestBoxSplitIndex = i + SplitsNumber * 2;
lowestSah = tmpSah;
axis = 2;
nLeft = zLeftN;
nRight = zRightN;
}
}
if (Ci * lowestSah > Triangles.Length || Depth > MaxDepth)
{
return;
}
Split = boxSplits[bestBoxSplitIndex];
SplitAxis = axis;
var splitTriangles = SplitTriangles(Split, axis, nLeft, nRight);
LeftNode = new KdTreeNode(splitTriangles[0], BoxMin, Split.LBoxMax, Depth + 1);
LeftNode.SplitNode();
RightNode = new KdTreeNode(splitTriangles[1], Split.RBoxMin, BoxMax, Depth + 1);
RightNode.SplitNode();
Triangles = null;
}
