/// <summary>
/// Calculates the tangent visibility graph
/// </summary>
/// <param name="obstacles">a list of polylines representing obstacles</param>
/// <returns></returns>
public static VisibilityGraph FillVisibilityGraphForShortestPath(IEnumerable <Polyline> obstacles)
{
var holes = new List <Polyline>(OrientHolesClockwise(obstacles));
var visibilityGraph = CalculateGraphOfBoundaries(holes);
var polygons = holes.Select(hole => new Polygon(hole)).ToList();
TangentVisibilityGraphCalculator.AddTangentVisibilityEdgesToGraph(polygons, visibilityGraph);
return(visibilityGraph);
}
internal static void AddTangentVisibilityEdgesToGraph(List <Polygon> holes, VisibilityGraph visibilityGraph)
{
if (holes.Count > 1)
{
TangentVisibilityGraphCalculator calculator = new TangentVisibilityGraphCalculator(holes, visibilityGraph, true);
calculator.CalculateAndAddEdges();
//use another family of tangents
calculator = new TangentVisibilityGraphCalculator(holes, visibilityGraph, false);
calculator.CalculateAndAddEdges();
}
}
internal static void AddTangentVisibilityEdgesToGraph(List<Polygon> holes, VisibilityGraph visibilityGraph) {
if (holes.Count > 1) {
TangentVisibilityGraphCalculator calculator = new TangentVisibilityGraphCalculator(holes, visibilityGraph, true);
calculator.CalculateAndAddEdges();
//use another family of tangents
calculator = new TangentVisibilityGraphCalculator(holes, visibilityGraph, false);
calculator.CalculateAndAddEdges();
}
}
/// <summary>
///
/// </summary>
/// <param name="pathStart"></param>
/// <param name="pathEnd"></param>
/// <param name="obstacles"></param>
/// <param name="sourceVertex">graph vertex corresponding to the source</param>
/// <param name="targetVertex">graph vertex corresponding to the target</param>
/// <returns></returns>
internal static VisibilityGraph GetVisibilityGraphForShortestPath(Point pathStart, Point pathEnd,
IEnumerable <Polyline> obstacles,
out VisibilityVertex sourceVertex,
out VisibilityVertex targetVertex)
{
var holes = new List <Polyline>(OrientHolesClockwise(obstacles));
var visibilityGraph = CalculateGraphOfBoundaries(holes);
var polygons = holes.Select(hole => new Polygon(hole)).ToList();
TangentVisibilityGraphCalculator.AddTangentVisibilityEdgesToGraph(polygons, visibilityGraph);
PointVisibilityCalculator.CalculatePointVisibilityGraph(holes, visibilityGraph, pathStart,
VisibilityKind.Tangent, out sourceVertex);
PointVisibilityCalculator.CalculatePointVisibilityGraph(holes, visibilityGraph, pathEnd,
VisibilityKind.Tangent, out targetVertex);
return(visibilityGraph);
}
