public static VertexFindResults Reject()
{
VertexFindResults vfr = new VertexFindResults();
vfr.ToUse = null;
vfr.EndRoad = true;
return(vfr);
}
public static VertexFindResults Accept(Vertex toUse, bool endRoad)
{
VertexFindResults vfr = new VertexFindResults();
vfr.ToUse = toUse;
vfr.EndRoad = endRoad;
return(vfr);
}
/// <summary>
/// Creates a new road from the given starting point along the given axis.
/// Takes care of adding the vertices and segments to their respective BVH.
/// </summary>
private Road Trace(Vertex start, bool useMajorAxis, int dir)
{
float stepInterval = RoadStepInterval * (float)dir;
//Step along the road in increments to build up the segments defining it.
Vector2 currentPos = start.Pos;
Vector2 currentVel = (float)dir * (useMajorAxis ?
GetBasis(start).Major :
GetBasis(start).Minor);
Road r = new Road();
r.Points.Add(start);
start.ConnectTo(r);
bool keepGoing = true;
Vertex newVert = start;
while (keepGoing)
{
//Get the next vertex along the road.
Vector2 nextPos = GetNext(newVert, stepInterval, currentVel, useMajorAxis);
VertexFindResults vfr = FindOrMakeVertex(r, nextPos);
newVert = vfr.ToUse;
if (newVert != null)
{
newVert.ConnectTo(r);
r.Points.Add(newVert);
Segments.Add(new Segment(r.Points[r.Points.Count - 2], newVert, r));
nextPos = newVert.Pos;
}
currentVel = nextPos - currentPos;
currentPos = nextPos;
keepGoing = !vfr.EndRoad;
}
//If the road is a dud, exit.
if (r.Points.Count < 2)
{
foreach (Vertex v in r.Points)
{
v.DisconnectFrom(r);
}
return(null);
}
//Finalize the road's data and return it.
r.UpdateBoundingBox();
return(r);
}
/// <summary>
/// Given a road and a new position to add to the road,
/// gets or creates a vertex to add to the road.
/// The vertex will always already be added to the vertex BVH.
/// If the returned vertex is null, it shouldn't be added to the road.
/// If "EndRoad" is true, the road should not continue on.
/// </summary>
private VertexFindResults FindOrMakeVertex(Road r, Vector2 nextPos)
{
Vertex lastPoint = r.Points[r.Points.Count - 1];
//Reject if the segment length is too short or its position is outside the city limits.
if (lastPoint.Pos.DistSqr(nextPos) <= (SegmentMinLength * SegmentMinLength) ||
!IsInBounds(nextPos))
{
return(VertexFindResults.Reject());
}
//If the next position is near another vertex, use that vertex and end the road there.
foreach (Vertex v in Vertices.GetAllNearbyPos(nextPos))
{
//Don't let the road loop back onto itself.
if (v.RoadsConnectedTo.Contains(r))
{
continue;
}
//Don't create a segment that already exists.
if (v.VertsConnectedTo.Contains(lastPoint))
{
return(VertexFindResults.Reject());
}
v.ConnectTo(lastPoint);
return(VertexFindResults.Accept(v, true));
}
Rect segBnds = new Rect().BoundByPoints(nextPos, lastPoint.Pos);
//If the segment intersects another segment, turn it into an intersection and continue.
List <Segment> segs = Segments.GetAllNearbyBnds(segBnds).ToList();
float t1 = float.NaN,
t2 = float.NaN;
Segment?hitSeg = null;
//Get any intersected segments.
//If we intersect with a previous part of this road, reject.
for (int i = 0; i < segs.Count; ++i)
{
float temp1 = float.NaN,
temp2 = float.NaN;
bool intersects = GeneratorUtils.SegmentsIntersect(lastPoint.Pos, nextPos,
segs[i].P1.Pos, segs[i].P2.Pos,
ref temp1, ref temp2);
if (segs[i].Owner == r ||
segs[i].P1.RoadsConnectedTo.Contains(r) ||
segs[i].P2.RoadsConnectedTo.Contains(r))
{
if (intersects)
{
return(VertexFindResults.Reject());
}
}
else if (intersects)
{
t1 = temp1;
t2 = temp2;
hitSeg = segs[i];
}
}
if (hitSeg.HasValue)
{
//Split up the road that the segment is a part of
// by adding a new vertex at the intersection.
Vertex vtx = new Vertex(hitSeg.Value.P1.Pos +
((hitSeg.Value.P2.Pos - hitSeg.Value.P1.Pos) * t2));
vtx.ConnectTo(lastPoint);
Vertices.Add(vtx);
SplitSegment(vtx, hitSeg.Value);
return(VertexFindResults.Accept(vtx, false));
}
//This segment isn't special in any way.
Vertex vert = new Vertex(nextPos);
vert.ConnectTo(lastPoint);
Vertices.Add(vert);
return(VertexFindResults.Accept(vert, false));
}