public ICollection <T> Query(Rectangle query)
{
var region = IntRect2.FromRectangle(query);
var results = new HashSet <T>();
var s = new Stack <Node>();
s.Push(Root);
while (s.Any())
{
var node = s.Pop();
if (node.Rect.IntersectsWith(region))
{
if (node.TopLeft == null)
{
foreach (var itemAndRect in node.ItemAndRects)
{
results.Add(itemAndRect.Item);
}
}
else
{
s.Push(node.TopLeft);
s.Push(node.TopRight);
s.Push(node.BottomLeft);
s.Push(node.BottomRight);
}
}
}
return(results);
}
public QuadTree(int subdivisionItemCountThreshold, int maxQuadDepth, IntRect2 bounds)
{
this.subdivisionItemCountThreshold = subdivisionItemCountThreshold;
this.maxQuadDepth = maxQuadDepth;
Root = new Node(0, bounds);
}
public void Insert(T item, IntRect2 regionRect)
{
var itemAndRect = new ItemAndRect {
Item = item, Rect = regionRect
};
InsertToNode(Root, itemAndRect);
}
private BvhILS2(BvhILS2 first, BvhILS2 second, IntLineSegment2[] segments, int segmentsStartIndexInclusive, int segmentsEndIndexExclusive, IntRect2 bounds)
{
First = first;
Second = second;
Segments = segments;
SegmentsStartIndexInclusive = segmentsStartIndexInclusive;
SegmentsEndIndexExclusive = segmentsEndIndexExclusive;
Bounds = bounds;
}
public static IntRect2 BoundingRectangles(IntRect2 first, IntRect2 second)
{
return(new IntRect2 {
Left = Math.Min(first.Left, second.Left),
Top = Math.Min(first.Top, second.Top),
Right = Math.Max(first.Right, second.Right),
Bottom = Math.Max(first.Bottom, second.Bottom)
});
}
public bool IntersectsWith(IntRect2 rect)
{
if (Right < rect.Left)
{
return(false);
}
if (Left > rect.Right)
{
return(false);
}
if (Bottom < rect.Top)
{
return(false);
}
if (Top > rect.Bottom)
{
return(false);
}
return(true);
}
public static BvhILS2 Build(IEnumerable <IntLineSegment2> segmentEnumerable)
{
var inputSegments = segmentEnumerable.ToArray();
var inputSegmentMidpoints = inputSegments.Map(s => s.ComputeMidpoint());
var segmentIndices = Util.Generate(inputSegments.Length, i => i);
var xComparer = Comparer <int> .Create((a, b) => inputSegmentMidpoints[a].X.CompareTo(inputSegmentMidpoints[b].X));
var yComparer = Comparer <int> .Create((a, b) => inputSegmentMidpoints[a].Y.CompareTo(inputSegmentMidpoints[b].Y));
var outputSegments = new IntLineSegment2[inputSegments.Length];
IntRect2 BoundingSegments(int startIndexInclusive, int endIndexExclusive)
{
cInt minX = cInt.MaxValue, minY = cInt.MaxValue, maxX = cInt.MinValue, maxY = cInt.MinValue;
for (var i = startIndexInclusive; i < endIndexExclusive; i++)
{
if (inputSegments[segmentIndices[i]].First.X < minX)
{
minX = inputSegments[segmentIndices[i]].First.X;
}
if (inputSegments[segmentIndices[i]].Second.X < minX)
{
minX = inputSegments[segmentIndices[i]].Second.X;
}
if (inputSegments[segmentIndices[i]].First.Y < minY)
{
minY = inputSegments[segmentIndices[i]].First.Y;
}
if (inputSegments[segmentIndices[i]].Second.Y < minY)
{
minY = inputSegments[segmentIndices[i]].Second.Y;
}
if (maxX < inputSegments[segmentIndices[i]].First.X)
{
maxX = inputSegments[segmentIndices[i]].First.X;
}
if (maxX < inputSegments[segmentIndices[i]].Second.X)
{
maxX = inputSegments[segmentIndices[i]].Second.X;
}
if (maxY < inputSegments[segmentIndices[i]].First.Y)
{
maxY = inputSegments[segmentIndices[i]].First.Y;
}
if (maxY < inputSegments[segmentIndices[i]].Second.Y)
{
maxY = inputSegments[segmentIndices[i]].Second.Y;
}
}
// ir2 is inclusive
return(new IntRect2 {
Left = minX, Top = minY, Right = maxX, Bottom = maxY
});
}
BvhILS2 BuildInternal(int startInclusive, int endExclusive, bool splitXElseY)
{
if (endExclusive - startInclusive < 16)
{
for (var i = startInclusive; i < endExclusive; i++)
{
outputSegments[i] = inputSegments[segmentIndices[i]];
}
return(new BvhILS2(null, null, outputSegments, startInclusive, endExclusive, BoundingSegments(startInclusive, endExclusive)));
}
Array.Sort(segmentIndices, startInclusive, endExclusive - startInclusive, splitXElseY ? xComparer : yComparer);
int midpoint = (startInclusive + endExclusive) / 2;
var first = BuildInternal(startInclusive, midpoint, !splitXElseY);
var second = BuildInternal(midpoint, endExclusive, !splitXElseY);
var bounds = IntRect2.BoundingRectangles(first.Bounds, second.Bounds);
return(new BvhILS2(first, second, outputSegments, startInclusive, endExclusive, bounds));
}
return(BuildInternal(0, inputSegments.Length, true));
}
public Node(int depth, IntRect2 rect)
{
Depth = depth;
Rect = rect;
}