private static bool CurveIntersectsHierarchy(LineSegment lineSeg, ParallelogramNode hierarchy)
{
if (hierarchy == null)
{
return(false);
}
if (!Parallelogram.Intersect(lineSeg.ParallelogramNodeOverICurve.Parallelogram, hierarchy.Parallelogram))
{
return(false);
}
ParallelogramBinaryTreeNode n = hierarchy as ParallelogramBinaryTreeNode;
if (n != null)
{
return(CurveIntersectsHierarchy(lineSeg, n.LeftSon) || CurveIntersectsHierarchy(lineSeg, n.RightSon));
}
return(Curve.CurveCurveIntersectionOne(lineSeg, ((ParallelogramNodeOverICurve)hierarchy).Seg, false) != null);
}
private bool BezierSegIntersectsTree(CubicBezierSegment seg, ParallelogramNode tree)
{
if (tree == null)
{
return(false);
}
if (Parallelogram.Intersect(seg.ParallelogramNodeOverICurve.Parallelogram, tree.Parallelogram))
{
ParallelogramBinaryTreeNode n = tree as ParallelogramBinaryTreeNode;
if (n != null)
{
return(BezierSegIntersectsTree(seg, n.LeftSon) || BezierSegIntersectsTree(seg, n.RightSon));
}
else
{
return(BezierSegIntersectsBoundary(seg, ((ParallelogramNodeOverICurve)tree).Seg));
}
}
else
{
return(false);
}
}
ParallelogramNode Calc(List <ParallelogramNode> nodes)
{
if (nodes.Count == 0)
{
return(null);
}
if (nodes.Count == 1)
{
return(nodes[0]);
}
//Finding the seeds
Parallelogram b0 = nodes[0].Parallelogram;
//the first seed
int seed0 = 1;
double area = new Parallelogram(b0, nodes[seed0].Parallelogram).Area;
for (int i = 2; i < nodes.Count; i++)
{
double area0 = new Parallelogram(b0, nodes[i].Parallelogram).Area;
if (area0 > area)
{
seed0 = i;
area = area0;
}
}
//Got the first seed seed0
//Now looking for a seed for the second group
int seed1 = 0; //the compiler forces me to init it
//init seed1
for (int i = 0; i < nodes.Count; i++)
{
if (i != seed0)
{
seed1 = i;
break;
}
}
area = new Parallelogram(nodes[seed0].Parallelogram, nodes[seed1].Parallelogram).Area;
//Now try to improve the second seed
for (int i = 0; i < nodes.Count; i++)
{
if (i == seed0)
{
continue;
}
double area1 = new Parallelogram(nodes[seed0].Parallelogram, nodes[i].Parallelogram).Area;
if (area1 > area)
{
seed1 = i;
area = area1;
}
}
//We have two seeds at hand. Build two groups.
List <ParallelogramNode> gr0 = new List <ParallelogramNode>();
List <ParallelogramNode> gr1 = new List <ParallelogramNode>();
gr0.Add(nodes[seed0]);
gr1.Add(nodes[seed1]);
Parallelogram box0 = nodes[seed0].Parallelogram;
Parallelogram box1 = nodes[seed1].Parallelogram;
//divide nodes on two groups
for (int i = 0; i < nodes.Count; i++)
{
if (i == seed0 || i == seed1)
{
continue;
}
Parallelogram box0_ = new Parallelogram(box0, nodes[i].Parallelogram);
double delta0 = box0_.Area - box0.Area;
Parallelogram box1_ = new Parallelogram(box1, nodes[i].Parallelogram);
double delta1 = box1_.Area - box1.Area;
//keep the tree roughly balanced
if (gr0.Count * groupSplitThreshold < gr1.Count)
{
gr0.Add(nodes[i]);
box0 = box0_;
}
else if (gr1.Count * groupSplitThreshold < gr0.Count)
{
gr1.Add(nodes[i]);
box1 = box1_;
}
else if (delta0 < delta1)
{
gr0.Add(nodes[i]);
box0 = box0_;
}
else
{
gr1.Add(nodes[i]);
box1 = box1_;
}
}
ParallelogramBinaryTreeNode ret = new ParallelogramBinaryTreeNode();
ret.Parallelogram = new Parallelogram(box0, box1);
ret.LeftSon = Calc(gr0);
ret.RightSon = Calc(gr1);
return(ret);
}
