public static Box Wrap(Box box0, Box box1)
{
box0.Include(box1);
return box0;
}
public static Box Wrap(Box box0, Box box1)
{
box0.Include(box1);
return(box0);
}
private static Node BuildNode(List <Entry> elements, Bucket[] buckets)
{
Box boundingBox = new Box(new Range(float.MaxValue, float.MinValue));
foreach (Entry e in elements)
{
boundingBox.Include(e.BoundingBox);
}
if (elements.Count <= 4)
{
LeafNode leaf = new LeafNode(boundingBox);
leaf.Elements = elements;
return(leaf);
}
InnerNode innerNode = new InnerNode(boundingBox);
Box centerVolume = new Box(new Range(float.MaxValue, float.MinValue));
foreach (Entry e in elements)
{
centerVolume.Include(e.BoundingBox.Center);
}
float minVolume = float.MaxValue;
int useAxis = -1;
int splitAtBucket = 0;
for (int axis = 0; axis < 3; axis++)
{
Range axisRange = centerVolume[axis];
float extend = axisRange.Extend;
if (extend == 0)
{
continue;
}
//extend = 1.0f;
foreach (Entry e in elements)
{
Bucket bucket = buckets[Math.Min(buckets.Length - 1, (int)((e.BoundingBox[axis].Center - axisRange.Min) / extend * buckets.Length))];
bucket.Elements.Add(e);
bucket.BoundingBox.Include(e.BoundingBox);
}
Box bounds = buckets[0].BoundingBox;
float volume = bounds.Volume;
buckets[0].VolumeUntilThis = volume;
for (int i = 1; i < buckets.Length; i++)
{
if (buckets[i].Elements.Count > 0)
{
bounds.Include(buckets[i].BoundingBox);
volume = bounds.Volume;
}
buckets[i].VolumeUntilThis = volume;
// Debug.WriteLine("volumeUntil(axis " + axis + ", bucket " + i + ") = " + volume);
}
bounds = buckets[buckets.Length - 1].BoundingBox;
volume = bounds.Volume;
buckets[buckets.Length - 1].VolumeFromThis = volume;
for (int i = buckets.Length - 2; i > -1; i--)
{
if (buckets[i].Elements.Count > 0)
{
bounds.Include(buckets[i].BoundingBox);
volume = bounds.Volume;
}
buckets[i].VolumeFromThis = volume;
//Debug.WriteLine("volumeFrom(axis " + axis + ", bucket " + i + ") = " + volume);
}
for (int b = 1; b < buckets.Length; b++)
{
volume = buckets[b - 1].VolumeUntilThis + buckets[b].VolumeFromThis;
if (volume < minVolume)
{
minVolume = volume;
useAxis = axis;
splitAtBucket = b;
}
//Debug.WriteLine("volume(axis " + axis + ", split " + b + ") = " + volume);
}
foreach (Bucket b in buckets)
{
b.Reset();
}
}
if (useAxis == -1)
{
LeafNode leaf = new LeafNode(boundingBox);
leaf.Elements = elements;
return(leaf);
}
Range axisRange2 = centerVolume[useAxis];
float extend2 = axisRange2.Extend;
Debug.Assert(extend2 != 0);
List <Entry> lower = new List <Entry>(),
upper = new List <Entry>();
foreach (Entry e in elements)
{
int bucketIndex = Math.Min(buckets.Length - 1, (int)((e.BoundingBox[useAxis].Center - axisRange2.Min) / extend2 * buckets.Length));
if (bucketIndex >= splitAtBucket)
{
upper.Add(e);
}
else
{
lower.Add(e);
}
}
innerNode.Axis = useAxis;
innerNode.Child0 = BuildNode(lower, buckets);
innerNode.Child1 = BuildNode(upper, buckets);
return(innerNode);
}