private static Dictionary <IPolygon, IMultiPatch> BuildResultMultipatches(
[NotNull] IMultiPatch prototype,
[NotNull] IDictionary <RingGroup, List <RingGroup> > splitResultsByFootprintPart,
DegenerateMultipatchFootprintAction nonSimpleBoundaryAction)
{
var result = new Dictionary <IPolygon, IMultiPatch>();
IRing emptyRing = GeometryFactory.CreateEmptyRing(prototype);
foreach (var outerRingsByFootprintPart in splitResultsByFootprintPart)
{
RingGroup footprintPart = outerRingsByFootprintPart.Key;
List <RingGroup> resultPolys = outerRingsByFootprintPart.Value;
IMultiPatch resultMultipatch =
GeometryFactory.CreateEmptyMultiPatch(prototype);
foreach (RingGroup poly in resultPolys)
{
// TODO: Support vertical ring group with inner rings
bool simplify = poly.InteriorRings.Any();
GeometryConversionUtils.AddRingGroup(
resultMultipatch, poly, simplify, poly.Id != null);
}
if (resultPolys.Any(p => p.Id != null))
{
GeometryUtils.MakePointIDAware(resultMultipatch);
}
// Guard against multipatches with wrong footprint. They are so broken (IRelationalOps are wrong) that
// it's not worth using them any further...
if (IsMultipatchWithDegenerateFootprint(resultMultipatch))
{
switch (nonSimpleBoundaryAction)
{
case DegenerateMultipatchFootprintAction.Throw:
throw new DegenerateResultGeometryException(
"The multipatch cut operation resulted in a multipatch with degenerate footprint.");
case DegenerateMultipatchFootprintAction.Discard:
_msg.DebugFormat(
"Discarding result multipatch with degenerate boundary: {0}",
GeometryUtils.ToString(resultMultipatch));
continue;
case DegenerateMultipatchFootprintAction.Keep:
_msg.DebugFormat(
"Detected result multipatch with degenerate boundary (it will be kept): {0}",
GeometryUtils.ToString(resultMultipatch));
break;
}
}
IPolygon footprintPoly =
GeometryConversionUtils.CreatePolygon(emptyRing, emptyRing, footprintPart);
result.Add(footprintPoly, resultMultipatch);
}
return(result);
}
/// <summary>
/// Cuts the provided multipatch along the specified cutLine.
/// </summary>
/// <param name="multipatch"></param>
/// <param name="cutLine"></param>
/// <param name="zSource">The source of the Z values to be used for the new vertices of the result features.</param>
/// <param name="usedCutLine">The cut result containing information about the cut operation.</param>
/// <param name="nonSimpleFootprintAction">The action to be performed if one of the result multipatches
/// has a degenerate footprint (because it is a sliver polygon with sub-tolerance self intersections).</param>
/// <returns></returns>
public static IDictionary <IPolygon, IMultiPatch> TryCut(
[NotNull] IMultiPatch multipatch,
[NotNull] IPolyline cutLine,
ChangeAlongZSource zSource,
[CanBeNull] CutPolyline usedCutLine = null,
DegenerateMultipatchFootprintAction nonSimpleFootprintAction =
DegenerateMultipatchFootprintAction.Throw)
{
Assert.ArgumentNotNull(multipatch, nameof(multipatch));
Assert.ArgumentNotNull(cutLine, nameof(cutLine));
bool allRings = GeometryUtils.IsRingBasedMultipatch(multipatch);
Assert.True(allRings,
"The multipatch geometry contains triangles, triangle fans or triangle strips, which are currently not supported");
// NOTE: ITopologicalOperator4 is not supported by multipatch, ITopologicalOperator3.Cut returns non-Z-aware polygons
// -> Use GeomUtils.Cut implementation which could eventually classify the left/right parts and avoid footprint-cutting
// only to find the correct assignment to result features.
// TODO: Create footprint as RingGroups directly from multipatch rings
IPolygon footprint = GeometryFactory.CreatePolygon(multipatch);
IList <IGeometry> cutFootprintParts =
TryCutRingGroups(footprint, cutLine, ChangeAlongZSource.Target);
if (cutFootprintParts == null || cutFootprintParts.Count == 0)
{
_msg.DebugFormat(
"Not even the footprint could be cut. No multipatch cutting performed.");
if (usedCutLine != null)
{
usedCutLine.Polyline = cutLine;
usedCutLine.SuccessfulCut = false;
}
return(new Dictionary <IPolygon, IMultiPatch>(0));
}
// Get the 'connected components', i.e. outer ring with respective inner rings.
IList <GeometryPart> multipatchParts =
GeometryPart.FromGeometry(multipatch).ToList();
Dictionary <RingGroup, List <RingGroup> > splitPartsByFootprintPart =
PrepareSplitPartsDictionary(cutFootprintParts);
foreach (GeometryPart part in multipatchParts)
{
CutAndAssignToFootprintParts(part, cutLine, splitPartsByFootprintPart,
zSource);
}
// make a separate multipatch per footprint-part with all respective ring-groups
Dictionary <IPolygon, IMultiPatch> result = BuildResultMultipatches(
multipatch, splitPartsByFootprintPart, nonSimpleFootprintAction);
if (usedCutLine != null && splitPartsByFootprintPart.Values.Count > 1)
{
// TODO: Extract actual cutLine from inBound/outBound intersections
usedCutLine.Polyline = cutLine;
usedCutLine.SuccessfulCut = false;
}
return(result);
}
