BoxGeometry constructor

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

Implementation

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

  // segments

  int wSeg = Math.floor(widthSegments);
  int hSeg = Math.floor(heightSegments);
  int dSeg = Math.floor(depthSegments);

  // buffers

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

  // helper variables

  numberOfVertices = 0;
  groupStart = 0;

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

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

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

    var vertexCounter = 0;
    var groupCount = 0;

    var vector = Vector3.init();

    // generate vertices, normals and uvs

    // print("buildPlane: u: ${u} v: ${v} w: ${w} udir: ${udir} vdir: ${vdir} width: ${width} height: ${height} depth: ${depth} gridX: ${gridX} gridY: ${gridY} materialIndex: ${materialIndex} ");

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

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

        // print("iy: ${iy} ix: ${ix} y: ${y} x: ${x} depthHalf: ${depthHalf} ");

        // set values to correct vector component

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

        vector.setP(u, x * udir);
        vector.setP(v, y * vdir);
        vector.setP(w, depthHalf);

        // now apply vector to vertex buffer

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

        // set values to correct vector component

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

        vector.setP(u, 0);
        vector.setP(v, 0);
        vector.setP(w, depth > 0 ? 1 : -1);

        // now apply vector to normal buffer

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

        // uvs

        uvs.add(ix / gridX);
        uvs.add(1 - (iy / gridY));

        // counters

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

        // faces

        indices.addAll([a, b, d]);
        indices.addAll([b, c, d]);

        // increase counter

        groupCount += 6;
      }
    }

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

    addGroup(groupStart, groupCount, materialIndex);

    // calculate new start value for groups

    groupStart += groupCount;

    // update total number of vertices

    numberOfVertices += vertexCounter;
  }

  // build each side of the box geometry

  buildPlane('z', 'y', 'x', -1, -1, depth, height, width, dSeg, hSeg, 0); // px
  buildPlane('z', 'y', 'x', 1, -1, depth, height, -width, dSeg, hSeg, 1); // nx
  buildPlane('x', 'z', 'y', 1, 1, width, depth, height, wSeg, dSeg, 2); // py
  buildPlane('x', 'z', 'y', 1, -1, width, depth, -height, wSeg, dSeg, 3); // ny
  buildPlane('x', 'y', 'z', 1, -1, width, height, depth, wSeg, hSeg, 4); // pz
  buildPlane('x', 'y', 'z', -1, -1, width, height, -depth, wSeg, hSeg, 5); // nz

  // build geometry

  setIndex(indices);
  setAttribute('position', Float32BufferAttribute(Float32Array.from(vertices), 3, false));
  setAttribute('normal', Float32BufferAttribute(Float32Array.from(normals), 3, false));
  setAttribute('uv', Float32BufferAttribute(Float32Array.from(uvs), 2, false));
}