SphereGeometry.js

import Cartesian3 from "./Cartesian3.js";
import Check from "./Check.js";
import defaultValue from "./defaultValue.js";
import defined from "./defined.js";
import EllipsoidGeometry from "./EllipsoidGeometry.js";
import VertexFormat from "./VertexFormat.js";

/**
 * A description of a sphere centered at the origin.
 *
 * @alias SphereGeometry
 * @constructor
 *
 * @param {Object} [options] Object with the following properties:
 * @param {Number} [options.radius=1.0] The radius of the sphere.
 * @param {Number} [options.stackPartitions=64] The number of times to partition the ellipsoid into stacks.
 * @param {Number} [options.slicePartitions=64] The number of times to partition the ellipsoid into radial slices.
 * @param {VertexFormat} [options.vertexFormat=VertexFormat.DEFAULT] The vertex attributes to be computed.
 *
 * @exception {DeveloperError} options.slicePartitions cannot be less than three.
 * @exception {DeveloperError} options.stackPartitions cannot be less than three.
 *
 * @see SphereGeometry#createGeometry
 *
 * @example
 * const sphere = new Cesium.SphereGeometry({
 *   radius : 100.0,
 *   vertexFormat : Cesium.VertexFormat.POSITION_ONLY
 * });
 * const geometry = Cesium.SphereGeometry.createGeometry(sphere);
 */
function SphereGeometry(options) {
  const radius = defaultValue(options.radius, 1.0);
  const radii = new Cartesian3(radius, radius, radius);
  const ellipsoidOptions = {
    radii: radii,
    stackPartitions: options.stackPartitions,
    slicePartitions: options.slicePartitions,
    vertexFormat: options.vertexFormat,
  };

  this._ellipsoidGeometry = new EllipsoidGeometry(ellipsoidOptions);
  this._workerName = "createSphereGeometry";
}

/**
 * The number of elements used to pack the object into an array.
 * @type {Number}
 */
SphereGeometry.packedLength = EllipsoidGeometry.packedLength;

/**
 * Stores the provided instance into the provided array.
 *
 * @param {SphereGeometry} value The value to pack.
 * @param {Number[]} array The array to pack into.
 * @param {Number} [startingIndex=0] The index into the array at which to start packing the elements.
 *
 * @returns {Number[]} The array that was packed into
 */
SphereGeometry.pack = function (value, array, startingIndex) {
  //>>includeStart('debug', pragmas.debug);
  Check.typeOf.object("value", value);
  //>>includeEnd('debug');

  return EllipsoidGeometry.pack(value._ellipsoidGeometry, array, startingIndex);
};

const scratchEllipsoidGeometry = new EllipsoidGeometry();
const scratchOptions = {
  radius: undefined,
  radii: new Cartesian3(),
  vertexFormat: new VertexFormat(),
  stackPartitions: undefined,
  slicePartitions: undefined,
};

/**
 * Retrieves an instance from a packed array.
 *
 * @param {Number[]} array The packed array.
 * @param {Number} [startingIndex=0] The starting index of the element to be unpacked.
 * @param {SphereGeometry} [result] The object into which to store the result.
 * @returns {SphereGeometry} The modified result parameter or a new SphereGeometry instance if one was not provided.
 */
SphereGeometry.unpack = function (array, startingIndex, result) {
  const ellipsoidGeometry = EllipsoidGeometry.unpack(
    array,
    startingIndex,
    scratchEllipsoidGeometry
  );
  scratchOptions.vertexFormat = VertexFormat.clone(
    ellipsoidGeometry._vertexFormat,
    scratchOptions.vertexFormat
  );
  scratchOptions.stackPartitions = ellipsoidGeometry._stackPartitions;
  scratchOptions.slicePartitions = ellipsoidGeometry._slicePartitions;

  if (!defined(result)) {
    scratchOptions.radius = ellipsoidGeometry._radii.x;
    return new SphereGeometry(scratchOptions);
  }

  Cartesian3.clone(ellipsoidGeometry._radii, scratchOptions.radii);
  result._ellipsoidGeometry = new EllipsoidGeometry(scratchOptions);
  return result;
};

/**
 * Computes the geometric representation of a sphere, including its vertices, indices, and a bounding sphere.
 *
 * @param {SphereGeometry} sphereGeometry A description of the sphere.
 * @returns {Geometry|undefined} The computed vertices and indices.
 */
SphereGeometry.createGeometry = function (sphereGeometry) {
  return EllipsoidGeometry.createGeometry(sphereGeometry._ellipsoidGeometry);
};
export default SphereGeometry;