public PolygonIntersection FindIntersectionPolygon(
IParametricSurface firstSurface,
IParametricSurface secondSurface,
Point3D intersectionNearPoint
)
{
_surfaces[0] = firstSurface;
_surfaces[1] = secondSurface;
var firstGuessParametrisation = NearestPointFinder.FindNearest(
_surfaces[0],
intersectionNearPoint
);
var secondGuessParametrisation = NearestPointFinder.FindNearest(
_surfaces[1],
intersectionNearPoint
);
firstGuessParametrisation.Boundaries =
firstSurface.ParametrisationBoundaries;
secondGuessParametrisation.Boundaries =
secondSurface.ParametrisationBoundaries;
var trackingDistanceSetting = TrackingDistance;
TrackingDistance = -trackingDistanceSetting;
var polygonPart = GetDirectionalPolygonPart(
firstGuessParametrisation,
secondGuessParametrisation
);
if (polygonPart.IsLooped)
{
return(polygonPart);
}
TrackingDistance = trackingDistanceSetting;
var polygonRemainingPart = GetDirectionalPolygonPart(
firstGuessParametrisation,
secondGuessParametrisation
);
if (polygonRemainingPart.IsLooped)
{
return(polygonRemainingPart);
}
return(PolygonIntersection.JoinFromSamePoint(
polygonPart,
polygonRemainingPart
));
}
private PolygonIntersection GetDirectionalPolygonPart(
Parametrisation firstGuessParametrisation,
Parametrisation secondGuessParametrisation
)
{
IntersectionParametrisation?previousParametrisation = null;
var currentIntersectionParametrisation = FindFirstIntersection(
firstGuessParametrisation,
secondGuessParametrisation
);
var polygon = new PolygonIntersection();
polygon.EqualityEpsilon = 0.001;
while (currentIntersectionParametrisation.HasValue &&
!AreEdgeTrackingBoundaryConditionsFullfilled(
previousParametrisation,
currentIntersectionParametrisation
)
)
{
if (polygon.FinishIfLoopedBack(
currentIntersectionParametrisation.Value
))
{
break;
}
polygon.Add(currentIntersectionParametrisation.Value);
var nextGuess = GetNextInitialGuess(
currentIntersectionParametrisation.Value
);
if (!nextGuess.HasValue)
{
break;
}
previousParametrisation = currentIntersectionParametrisation;
currentIntersectionParametrisation = FindFirstIntersection(
nextGuess.Value.First,
nextGuess.Value.Second
);
}
return(polygon);
}
public static PolygonIntersection JoinFromSamePoint(
PolygonIntersection left,
PolygonIntersection right
)
{
var rightSegment = right.Polygon.ToList();
rightSegment.Reverse();
var intersection = new PolygonIntersection
{
Polygon = rightSegment.Concat(left.Polygon).ToList()
};
return(intersection);
}
