private static double CalculateDistanceToNearestEndpoint(BspSegment segment, double tSegment)
{
Vec2D endpointVertex = (tSegment < 0.5 ? segment.Start.Struct() : segment.End.Struct());
Vec2D intersectionPoint = segment.FromTime(tSegment);
return(endpointVertex.Distance(intersectionPoint));
}
protected bool IntersectionTimeAtEndpoint(BspSegment segmentToSplit, double segmentTime, out Endpoint endpoint)
{
// Note that we cannot attempt to look up the endpoint, because it
// is possible that it may detect an unrelated vertex from a split
// on another side which happens to be right where the split would
// happen.
//
// For example, suppose a perpendicular split is going to occur.
// The vertical splitter line would intersect it like so at the X:
//
// o
// | Splitter
// o
//
// o----X----o
// Segment
//
// Now suppose that the bottom side of `Segment` was recursed on
// first, and some splitter happened to already create a vertex at
// the exact point that `Splitter` would hit `Segment` on the X. If
// we were to check the vertex allocator for whether a vertex is
// near/at X or not, it will return true. However this split will
// clearly not be hitting an endpoint of `Segment`, so we'd get a
// 'true' result when it is definitely not intersecting at/near an
// endpoint.
//
// Therefore our only solution is to do it by checking distances.
Vec2D vertex = segmentToSplit.FromTime(segmentTime);
if (vertex.Distance(segmentToSplit.Start) <= BspConfig.VertexWeldingEpsilon)
{
endpoint = Endpoint.Start;
return(true);
}
if (vertex.Distance(segmentToSplit.End) <= BspConfig.VertexWeldingEpsilon)
{
endpoint = Endpoint.End;
return(true);
}
endpoint = default;
return(false);
}