WireframeGeometry constructor

WireframeGeometry(BufferGeometry geometry)

geometry — any geometry object.

Implementation

WireframeGeometry(BufferGeometry geometry) : super() {
  type = "WireframeGeometry";
  // buffer

  List<double> vertices = [];
  final edges = <dynamic>{};

  // helper variables

  final start = Vector3.zero();
  final end = Vector3.zero();

  if (geometry.index != null) {
    // indexed BufferGeometry

    final position = geometry.attributes[Attribute.position.name];
    final indices = geometry.index;
    List<Map<String,dynamic>> groups = geometry.groups;

    if (groups.isEmpty) {
      groups = [{"start": 0, "count": indices!.count, "materialIndex": 0}];
    }

    // create a data structure that contains all eges without duplicates

    for (int o = 0, ol = groups.length; o < ol; ++o) {
      final group = groups[o];

      final groupStart = group["start"]!;
      final groupCount = group["count"]!;

      for (int i = groupStart, l = (groupStart + groupCount); i < l; i += 3) {
        for (int j = 0; j < 3; j++) {
          int index1 = indices!.getX(i + j)!.toInt();
          int index2 = indices.getX(i + (j + 1) % 3)!.toInt();

          start.fromBuffer(position!, index1);
          end.fromBuffer(position, index2);

          if (isUniqueEdge(start, end, edges) == true) {
            vertices.addAll(
                [start.x.toDouble(), start.y.toDouble(), start.z.toDouble()]);
            vertices.addAll(
                [end.x.toDouble(), end.y.toDouble(), end.z.toDouble()]);
          }
        }
      }
    }
  }
  else {
    // non-indexed BufferGeometry

    final position = geometry.attributes[Attribute.position.name];

    for (int i = 0, l = (position!.count ~/ 3); i < l; i++) {
      for (int j = 0; j < 3; j++) {
        // three edges per triangle, an edge is represented as (index1, index2)
        // e.g. the first triangle has the following edges: (0,1),(1,2),(2,0)

        final index1 = 3 * i + j;
        final index2 = 3 * i + ((j + 1) % 3);

        start.fromBuffer(position, index1);
        end.fromBuffer(position, index2);

        if (isUniqueEdge(start, end, edges) == true) {
          vertices.addAll(
              [start.x.toDouble(), start.y.toDouble(), start.z.toDouble()]);
          vertices
              .addAll([end.x.toDouble(), end.y.toDouble(), end.z.toDouble()]);
        }
      }
    }
  }

  // build geometry

  setAttribute(Attribute.position,Float32BufferAttribute.fromList(vertices, 3, false));
}