/// <summary>
/// Gets the segment at the vertices provided if it exists, or creates
/// it if not.
/// </summary>
/// <param name="start">The start vertex.</param>
/// <param name="end">The end vertex.</param>
/// <param name="line">The line (optional).</param>
/// <returns>Either a newly allocated BSP segment, or the one that
/// already exists with the information provided.</returns>
public BspSegment GetOrCreate(BspVertex start, BspVertex end, IBspUsableLine line = null)
{
Debug.Assert(start != end, "Cannot create a segment that is a point");
(int smallerIndex, int largerIndex) = start.Index.MinMax(end.Index);
if (segmentTable.TryGetValue(smallerIndex, out var largerValues))
{
if (largerValues.TryGetValue(largerIndex, out int segIndex))
{
return(segments[segIndex]);
}
largerValues[largerIndex] = segments.Count;
int newCollinearIndex = GetCollinearIndex(start, end);
return(CreateNewSegment(start, end, newCollinearIndex, line));
}
var largerIndexDict = new Dictionary <int, int> {
[largerIndex] = segments.Count
};
int collinearIndex = GetCollinearIndex(start, end);
segmentTable[smallerIndex] = largerIndexDict;
return(CreateNewSegment(start, end, collinearIndex, line));
}
/// <summary>
/// Creates a subsector edge from some geometric data and for some
/// side.
/// </summary>
/// <param name="start">The starting point.</param>
/// <param name="end">The ending point.</param>
/// <param name="line">The line this is on top of, or null if this is
/// a miniseg.</param>
/// <param name="front">True if this is on the front side, false if it
/// is the back. This value is not used if this is a miniseg. This
/// must never be false for a one sided line.</param>
public SubsectorEdge(Vec2D start, Vec2D end, IBspUsableLine line = null, bool front = true)
{
Start = start;
End = end;
IsFront = front;
Line = line;
}
private BspSegment CreateNewSegment(BspVertex start, BspVertex end, int collinearIndex,
IBspUsableLine line = null)
{
BspSegment seg = new BspSegment(start, end, collinearIndex, line);
segments.Add(seg);
return(seg);
}
/// <summary>
/// Creates a new BSP segment from the data provided. This will also
/// add itself to the vertices provided as an edge reference.
/// </summary>
/// <param name="start">The start vertex.</param>
/// <param name="end">The end vertex.</param>
/// <param name="collinearIndex">The index for collinearity. See
/// <see cref="CollinearTracker"/> for more info.</param>
/// <param name="line">The line (if any, this being null implies it is
/// a miniseg).</param>
public BspSegment(BspVertex start, BspVertex end, int collinearIndex, IBspUsableLine line = null) :
base(start, end)
{
Debug.Assert(start != end, "BSP segment shouldn't have a start and end index being the same");
StartVertex = start;
EndVertex = end;
CollinearIndex = collinearIndex;
Line = new Optional <IBspUsableLine>(line);
start.Edges.Add(this);
end.Edges.Add(this);
Debug.Assert(Length() >= 0.00001, "Extremely small BSP segment detected");
}
