public static (bool success, IEnumerable <uint> missingTiles) AssignFaces(this TiledBarrierGraph graph,
uint tile)
{
if (!graph.HasTile(tile))
{
return(false, new[] { tile });
}
var tileBox = TileStatic.Box(graph.Zoom, tile);
var tilesMissing = new HashSet <uint>();
graph.ResetFaces();
// the default face for the case where a loop cannot be found.
var unAssignableFace = graph.AddFace();
// check each edges for faces and if missing assign them.
var enumerator = graph.GetEnumerator();
for (var v = 0; v < graph.VertexCount; v++)
{
if (!enumerator.MoveTo(v))
{
continue;
}
if (!enumerator.MoveNext())
{
continue;
}
var vBox = graph.GetVertexBox(v);
if (vBox == null || !vBox.Value.Overlaps(tileBox))
{
continue;
}
// var vTile = TileStatic.WorldTileLocalId(vLocation.longitude, vLocation.latitude, graph.Zoom);
// if (vTile != tile) continue;
enumerator.MoveTo(v);
while (enumerator.MoveNext())
{
if (enumerator.Forward && enumerator.FaceRight != int.MaxValue)
{
continue;
}
if (!enumerator.Forward && enumerator.FaceLeft != int.MaxValue)
{
continue;
}
// check if the edge bbox overlaps the tiles.
var eBox = enumerator.Box;
if (!eBox.Overlaps(tileBox))
{
continue;
}
// ok this edge has an undetermined face.
var result = enumerator.AssignFace(unAssignableFace);
if (!result.success)
{
tilesMissing.UnionWith(result.missingTiles);
}
}
}
if (tilesMissing.Count > 0)
{
return(false, tilesMissing);
}
return(true, Enumerable.Empty <uint>());
}
