public IEventPoint Pop()
{
IEventPoint next = eventQueue.Pop();
if (intersectionsToIgnore.Contains(next))
{
return(Pop());
}
return(next);
}
public bool IsEmpty()
{
if (eventQueue.IsEmpty())
{
return(true);
}
IEventPoint next = eventQueue.Peek();
if (intersectionsToIgnore.Contains(next))
{
eventQueue.Pop();
return(IsEmpty());
}
return(false);
}
internal Dictionary <Point, VoronoiCellUnorganised> WithPoints(IEnumerable <Point> points)
{
if (points.Count() == 0)
{
throw new System.ArgumentException("No points provided");
}
cells = new Dictionary <Point, VoronoiCellUnorganised>();
// We'll start at the top of the field and work down.
// Initialise the beachline with all points having most Y coordinate.
// There'll often be only one of these, but calculating their interactions
// with no background beachline is more difficult so it helps to include them all at once.
HashSet <Point> distinctPoints = new HashSet <Point>(points);
List <Point> highestPoints = FindHighestPoints(distinctPoints).OrderBy(p => p.x).ToList();
float mostY = highestPoints.First().y;
IEnumerable <Point> otherPoints = distinctPoints.Where(p => p.y < mostY);
List <BeachSection> initialBeachSections = new List <BeachSection>();
for (int i = 0; i < highestPoints.Count; i++)
{
Point left = null;
Point right = null;
Point focus = highestPoints[i];
cells[focus] = new VoronoiCellUnorganised(focus);
if (i > 0)
{
left = highestPoints[i - 1];
cells[focus].AddBorder(left);
}
if (i + 1 < highestPoints.Count)
{
right = highestPoints[i + 1];
cells[focus].AddBorder(right);
}
BeachSection bs = new BeachSection(focus, left, right);
initialBeachSections.Add(bs);
}
BeachLine beachLine = new BeachLine(initialBeachSections, otherPoints);
// For the remaining points that don't lie on the initial beachline, handle them in descending order
// of their y coordinate.
while (beachLine.HasMoreEvents())
{
IEventPoint eventPoint = beachLine.PopEvent();
if (eventPoint.EventType() == "Site")
{
Point site = eventPoint.Point();
BeachSection containingBeachSection = beachLine.BeachSectionContainingPoint(site);
VoronoiCellUnorganised cell = new VoronoiCellUnorganised(site);
cells[site] = cell;
AddBorderBetweenCells(site, containingBeachSection.focus);
beachLine.SplitBeachSection(site);
}
else // EventType = "Intersect"
{
IntersectEventPoint intersectEventPoint = (IntersectEventPoint)eventPoint;
BeachSection consumedBeachSection = intersectEventPoint.consumedBeachSection;
AddBorderBetweenCells(consumedBeachSection.leftBoundary, consumedBeachSection.rightBoundary);
beachLine.ConsumeBeachSection(intersectEventPoint);
}
}
return(cells);
}
public void Remove(IEventPoint eventPoint)
{
intersectionsToIgnore.Add(eventPoint);
}
public void Add(IEventPoint eventPoint)
{
eventQueue.Add(eventPoint);
}