public BoundingVolumeHierarchy(List<Boundable> boundables)
{
_logNumBoundables = (int)Math.Ceiling(Math.Log(boundables.Count));
var time = DateTime.UtcNow;
Console.WriteLine($"Building BVH for {boundables.Count} boundables...");
Root = Construct(new BVHNode(boundables));
Console.WriteLine($"Constuction done in {DateTime.UtcNow - time}");
}
public BoundingVolumeHierarchy(List <Boundable> boundables)
{
_logNumBoundables = (int)Math.Ceiling(Math.Log(boundables.Count));
var time = DateTime.UtcNow;
Console.WriteLine($"Building BVH for {boundables.Count} boundables...");
Root = Construct(new BVHNode(boundables));
Console.WriteLine($"Constuction done in {DateTime.UtcNow - time}");
}
public BVHNode Construct(BVHNode leaf)
{
if (leaf.Boundables.Count == 0)
{
return(leaf);
}
var bb = BoundingBox.FromBoundables(leaf.Boundables);
var xLen = bb.Max.X - bb.Min.X;
var yLen = bb.Max.Y - bb.Min.Y;
var zLen = bb.Max.Z - bb.Min.Z;
List <Boundable> sorted;
if (xLen > yLen && xLen > zLen)
{
sorted = leaf.Boundables.OrderBy(x => x.BoundingBox.Centroid.X).ToList();
}
else if (yLen > xLen && yLen > zLen)
{
sorted = leaf.Boundables.OrderBy(x => x.BoundingBox.Centroid.Y).ToList();
}
else
{
sorted = leaf.Boundables.OrderBy(x => x.BoundingBox.Centroid.Z).ToList();
}
var bestPlane = CalculateBestSplitPlane(sorted);
//don't split further
if (bestPlane.Cost > leaf.BoundingBox.Area * leaf.Boundables.Count)
{
return(leaf);
}
var left = new BVHNode(bestPlane.Left);
var right = new BVHNode(bestPlane.Right);
var parent = new BVHNode(Construct(left), Construct(right));
return(parent);
}
public BVHNode Construct(BVHNode leaf)
{
if (leaf.Boundables.Count == 0)
{
return leaf;
}
var bb = BoundingBox.FromBoundables(leaf.Boundables);
var xLen = bb.Max.X - bb.Min.X;
var yLen = bb.Max.Y - bb.Min.Y;
var zLen = bb.Max.Z - bb.Min.Z;
List<Boundable> sorted;
if (xLen > yLen && xLen > zLen)
{
sorted = leaf.Boundables.OrderBy(x => x.BoundingBox.Centroid.X).ToList();
}
else if (yLen > xLen && yLen > zLen)
{
sorted = leaf.Boundables.OrderBy(x => x.BoundingBox.Centroid.Y).ToList();
}
else
{
sorted = leaf.Boundables.OrderBy(x => x.BoundingBox.Centroid.Z).ToList();
}
var bestPlane = CalculateBestSplitPlane(sorted);
//don't split further
if (bestPlane.Cost > leaf.BoundingBox.Area*leaf.Boundables.Count)
{
return leaf;
}
var left = new BVHNode(bestPlane.Left);
var right = new BVHNode(bestPlane.Right);
var parent = new BVHNode(Construct(left), Construct(right));
return parent;
}
public BVHNode(BVHNode left, BVHNode right)
{
_left = left;
_right = right;
BoundingBox = BoundingBox.Combine(left.BoundingBox, right.BoundingBox);
}
public BVHNode(BVHNode left)
{
_left = left;
BoundingBox = left.BoundingBox;
}
public BVHNode(BVHNode left, BVHNode right)
{
_left = left;
_right = right;
BoundingBox = BoundingBox.Combine(left.BoundingBox, right.BoundingBox);
}
public BVHNode(BVHNode left)
{
_left = left;
BoundingBox = left.BoundingBox;
}