private static CrossSectionCurve GenerateCrossSection(List <Line> meshLines, int numCrossSections)
{
CrossSectionCurve curve = new CrossSectionCurve();
List <CrossSectionEvent> eventQueue = GenerateEventQueue(meshLines, numCrossSections);
HashSet <Line> currentLines = new HashSet <Line>();
for (int i = 0; i < eventQueue.Count; i++)
{
CrossSectionEvent currentEvent = eventQueue[i];
if (currentEvent.crossSectionCut)
{
//Calc cross section from current lines using convex hull algorithm
curve.AddCrossSection(GenerateCrossSectionFromLines(currentLines, currentEvent.point));
}
else
{
Line currentLine = currentEvent.line;
if (!currentLines.Remove(currentLine))
{
currentLines.Add(currentLine);
}
}
}
return(curve);
}
private static List <CrossSectionEvent> GenerateEventQueue(List <Line> meshLines, int numCrossSections)
{
float upperBound = float.NegativeInfinity, lowerBound = float.PositiveInfinity;
LLRedBlackTree <CrossSectionEvent> eventQueue = new LLRedBlackTree <CrossSectionEvent>();
for (int i = 0; i < meshLines.Count; i++)
{
Line line = meshLines[i];
CrossSectionEvent point1Event = new CrossSectionEvent();
CrossSectionEvent point2Event = new CrossSectionEvent();
point1Event.line = line;
point1Event.point = line.point1.y;
point1Event.crossSectionCut = false;
eventQueue.Insert(point1Event);
point2Event.line = line;
point2Event.point = line.point2.y;
point2Event.crossSectionCut = false;
eventQueue.Insert(point2Event);
upperBound = Math.Max(upperBound, line.point1.y);
upperBound = Math.Max(upperBound, line.point2.y);
lowerBound = Math.Min(lowerBound, line.point1.y);
lowerBound = Math.Min(lowerBound, line.point2.y);
}
upperBound -= float.Epsilon * 16;
lowerBound += float.Epsilon * 16;
float stepSize = (upperBound - lowerBound) / ((float)numCrossSections - 1);
for (int i = 0; i < numCrossSections; i++)
{
CrossSectionEvent crossSectionCut = new CrossSectionEvent();
crossSectionCut.point = stepSize * (float)i + lowerBound;
crossSectionCut.crossSectionCut = true;
eventQueue.Insert(crossSectionCut);
}
return(eventQueue.InOrderTraversal());
}