private static List <SubsectorEdge> CreateSubsectorEdges(ConvexTraversal convexTraversal, Rotation rotation)
{
List <ConvexTraversalPoint> traversal = convexTraversal.Traversal;
Debug.Assert(traversal.Count >= 3, "Traversal must yield at least a triangle in size");
List <SubsectorEdge> subsectorEdges = new List <SubsectorEdge>();
ConvexTraversalPoint firstTraversal = traversal.First();
Vec2D startPoint = firstTraversal.Vertex;
foreach (ConvexTraversalPoint traversalPoint in traversal)
{
BspSegment segment = traversalPoint.Segment;
Vec2D endingPoint = segment.Opposite(traversalPoint.Endpoint).Struct();
bool traversedFrontSide = CheckIfTraversedFrontSide(traversalPoint, rotation);
SubsectorEdge edge = new SubsectorEdge(startPoint, endingPoint, segment.Line.Value, traversedFrontSide);
subsectorEdges.Add(edge);
Debug.Assert(startPoint != endingPoint, "Traversal produced the wrong endpoint indices");
startPoint = endingPoint;
}
Debug.Assert(subsectorEdges.Count == traversal.Count, "Added too many subsector edges in traversal");
return(subsectorEdges);
}
/// <summary>
/// Takes the convex traversal that was done and adds it to the top BSP
/// node on the stack. This effectively creates the subsector.
/// </summary>
private void AddConvexTraversalToTopNode()
{
Debug.Assert(!workItems.Empty(), "Cannot add convex traversal to an empty work item stack");
ConvexTraversal traversal = ConvexChecker.States.ConvexTraversal;
Rotation rotation = ConvexChecker.States.Rotation;
List <SubsectorEdge> edges = SubsectorEdge.FromClockwiseTraversal(traversal, rotation);
workItems.Peek().Node.ClockwiseEdges = edges;
}
/// <summary>
/// Using the convex traversal and the rotation of the traversal, this
/// will create a clockwise traversal to form the final subsector for
/// a BSP node.
/// </summary>
/// <param name="convexTraversal">The traversal we did earlier that
/// resulted in a convex subsector.</param>
/// <param name="rotation">What direction that traversal went.</param>
/// <returns>A convex series of sequential subsector edges that make up
/// the closed subsector.</returns>
public static List <SubsectorEdge> FromClockwiseTraversal(ConvexTraversal convexTraversal, Rotation rotation)
{
List <SubsectorEdge> edges = CreateSubsectorEdges(convexTraversal, rotation);
if (rotation == Rotation.Left)
{
edges.ForEach(edge => edge.Reverse());
edges.Reverse();
}
// TODO: Assert valid subsector edges!
return(edges);
}
