BoxGeometry constructor

BoxGeometry([ double width = 1, double height = 1, double depth = 1, int widthSegments = 1, int heightSegments = 1, int depthSegments = 1, ])

width — Width; that is, the length of the edges parallel to the X axis. Optional; defaults to 1.

height — Height; that is, the length of the edges parallel to the Y axis. Optional; defaults to 1.

depth — Depth; that is, the length of the edges parallel to the Z axis. Optional; defaults to 1.

widthSegments — Number of segmented rectangular faces along the width of the sides. Optional; defaults to 1.

heightSegments — Number of segmented rectangular faces along the height of the sides. Optional; defaults to 1.

depthSegments — Number of segmented rectangular faces along the depth of the sides. Optional; defaults to 1.

Implementation

BoxGeometry([
  double width = 1,
  double height = 1,
  double depth = 1,
  int widthSegments = 1,
  int heightSegments = 1,
  int depthSegments = 1
]):super() {
  type = "BoxGeometry";

  parameters = {
    "width": width,
    "height": height,
    "depth": depth,
    "widthSegments": widthSegments,
    "heightSegments": heightSegments,
    "depthSegments": depthSegments
  };

  List<int> indices = [];
  List<double> vertices = [];
  List<double> normals = [];
  List<double> uvs = [];

  // helper variables

  numberOfVertices = 0;
  groupStart = 0;

  void buildPlane(int u, int v, int w, double udir, double vdir, double width, double height, double depth, int gridX, int gridY, int materialIndex) {
    final segmentWidth = width / gridX;
    final segmentHeight = height / gridY;

    final widthHalf = width / 2;
    final heightHalf = height / 2;
    final depthHalf = depth / 2;

    final gridX1 = gridX + 1;
    final gridY1 = gridY + 1;

    int vertexCounter = 0;
    int groupCount = 0;

    final vector = Vector3.zero();

    for (int iy = 0; iy < gridY1; iy++) {
      final y = iy * segmentHeight - heightHalf;

      for (int ix = 0; ix < gridX1; ix++) {
        final x = ix * segmentWidth - widthHalf;

        vector[u] = x * udir;
        vector[v] = y * vdir;
        vector[w] = depthHalf;

        vertices.addAll([vector.x.toDouble(), vector.y.toDouble(), vector.z.toDouble()]);

        vector[u] = 0;
        vector[v] = 0;
        vector[w] = depth > 0 ? 1 : -1;

        normals.addAll([vector.x.toDouble(), vector.y.toDouble(), vector.z.toDouble()]);
        uvs.add(ix / gridX);
        uvs.add(1 - (iy / gridY));

        vertexCounter += 1;
      }
    }

    // indices

    // 1. you need three indices to draw a single face
    // 2. a single segment consists of two faces
    // 3. so we need to generate six (2*3) indices per segment

    for (int iy = 0; iy < gridY; iy++) {
      for (int ix = 0; ix < gridX; ix++) {
        final a = numberOfVertices + ix + gridX1 * iy;
        final b = numberOfVertices + ix + gridX1 * (iy + 1);
        final c = numberOfVertices + (ix + 1) + gridX1 * (iy + 1);
        final d = numberOfVertices + (ix + 1) + gridX1 * iy;

        indices.addAll([a, b, d]);
        indices.addAll([b, c, d]);
        groupCount += 6;
      }
    }

    // add a group to the geometry. this will ensure multi material support

    addGroup(groupStart, groupCount, materialIndex);
    groupStart += groupCount;
    numberOfVertices += vertexCounter;
  }

  // build each side of the box geometry

  buildPlane(2,1,0, -1, -1, depth, height, width, depthSegments,heightSegments, 0); // px
  buildPlane(2,1,0, 1, -1, depth, height, -width, depthSegments,heightSegments, 1); // nx
  buildPlane(0,2,1, 1, 1, width, depth, height, widthSegments,depthSegments, 2); // py
  buildPlane(0,2,1, 1, -1, width, depth, -height, widthSegments,depthSegments, 3); // ny
  buildPlane(0,1,2, 1, -1, width, height, depth, widthSegments,heightSegments, 4); // pz
  buildPlane(0,1,2, -1, -1, width, height, -depth, widthSegments,heightSegments, 5); // nz

  // build geometry

  setIndex(indices);
  setAttributeFromString('position',Float32BufferAttribute.fromList(vertices, 3, false));
  setAttributeFromString('normal',Float32BufferAttribute.fromList(normals, 3, false));
  setAttributeFromString('uv', Float32BufferAttribute.fromList(uvs, 2, false));
}