public KdNode(KdNodePlane plane, PosVector coord, List <IShape> list, KdNode nodeLeft, KdNode nodeRight)
{
Plane = plane;
Coord = coord;
Shapes = list;
Left = nodeLeft;
Right = nodeRight;
}
private (bool, BoundingBox, BoundingBox) SplitPlane(KdNode node, BoundingBox bbox, Ray ray)
{
(bool, BoundingBox, BoundingBox) ExplicitSplitPlane(bool match)
{
if (match)
{
var(fbox, backbox) = SplitBoundingBox(bbox, node.Plane, node.Coord);
return(true, fbox, backbox);
}
else
{
var(backbox, fbox) = SplitBoundingBox(bbox, node.Plane, node.Coord);
return(false, fbox, backbox);
}
}
switch (node.Plane)
{
case KdNodePlane.XY:
return(ExplicitSplitPlane(
((node.Coord.Z > bbox.BoxMin.Z) && (node.Coord.Z > ray.Position.Z)) ||
((node.Coord.Z < bbox.BoxMin.Z) && (node.Coord.Z < ray.Position.Z))));
case KdNodePlane.XZ:
return(ExplicitSplitPlane(
((node.Coord.Y > bbox.BoxMin.Y) && (node.Coord.Y > ray.Position.Y)) ||
((node.Coord.Y < bbox.BoxMin.Y) && (node.Coord.Y < ray.Position.Y))));
case KdNodePlane.YZ:
return(ExplicitSplitPlane(
((node.Coord.X > bbox.BoxMin.X) && (node.Coord.X > ray.Position.X)) ||
((node.Coord.X < bbox.BoxMin.X) && (node.Coord.X < ray.Position.X))));
default:
throw new InvalidOperationException();
}
}
private IntersectionInfo FindIntersectionNode(KdNode node, BoundingBox bbox, Ray ray)
{
if (node == null)
{
return(new IntersectionInfo());
}
if (node.Plane == KdNodePlane.NoPlane)
{
// leaf node
var bestInfo = new IntersectionInfo();
foreach (var shape in node.Shapes)
{
var info = shape.Intersect(ray);
if (info.IsHit)
{
// if (bbox.IsPointInside(info.Position))
{
if (info.Distance < bestInfo.Distance && info.Distance >= 0.0)
{
bestInfo = info;
}
}
}
}
if (bestInfo.IsHit)
{
return(bestInfo);
}
else
{
return(new IntersectionInfo());
}
}
var(leftIsFront, frontBbox, backBbox) = SplitPlane(node, bbox, ray);
var frontNode = leftIsFront ? node.Left : node.Right;
var backNode = leftIsFront ? node.Right : node.Left;
if (IsBoundingBoxIntersection(frontBbox, ray))
{
var intInfo = FindIntersectionNode(frontNode, frontBbox, ray);
if (intInfo.IsHit)
{
return(intInfo);
}
else
{
if (IsBoundingBoxIntersection(backBbox, ray))
{
intInfo = FindIntersectionNode(backNode, backBbox, ray);
return(intInfo.IsHit ? intInfo : new IntersectionInfo());
}
else
{
return(new IntersectionInfo());
}
}
}
else
{
return(new IntersectionInfo());
}
}
private KdTree(KdNode root, BoundingBox bbox)
{
Root = root;
BoundingBox = bbox;
}