terriajs-cesium/Source/Core/Cartesian2.js

CesiumJS is a JavaScript library for creating 3D globes and 2D maps in a web browser without a plugin.

// @ts-check

import Check from "./Check.js";
import defined from "./defined.js";
import DeveloperError from "./DeveloperError.js";
import CesiumMath from "./Math.js";

/** @import {TypedArray} from "./globalTypes.js"; */
/** @import Cartesian3 from "./Cartesian3.js"; */
/** @import Cartesian4 from "./Cartesian4.js"; */

/**
 * A 2D Cartesian point.
 *
 * @see Cartesian3
 * @see Cartesian4
 * @see Packable
 */
class Cartesian2 {
  /**
   * @param {number} [x=0.0] The X component.
   * @param {number} [y=0.0] The Y component.
   */
  constructor(x, y) {
    /**
     * The X component.
     * @type {number}
     * @default 0.0
     */
    this.x = x ?? 0.0;

    /**
     * The Y component.
     * @type {number}
     * @default 0.0
     */
    this.y = y ?? 0.0;
  }

  /**
   * Creates a Cartesian2 instance from x and y coordinates.
   *
   * @param {number} x The x coordinate.
   * @param {number} y The y coordinate.
   * @param {Cartesian2} [result] The object onto which to store the result.
   * @returns {Cartesian2} The modified result parameter or a new Cartesian2 instance if one was not provided.
   */
  static fromElements(x, y, result) {
    if (!defined(result)) {
      return new Cartesian2(x, y);
    }

    result.x = x;
    result.y = y;
    return result;
  }

  /**
   * Duplicates a Cartesian2 instance.
   *
   * @param {Cartesian2} cartesian The Cartesian to duplicate.
   * @param {Cartesian2} [result] The object onto which to store the result.
   * @returns {Cartesian2} The modified result parameter or a new Cartesian2 instance if one was not provided. (Returns undefined if cartesian is undefined)
   */
  static clone(cartesian, result) {
    if (!defined(cartesian)) {
      return undefined;
    }
    if (!defined(result)) {
      return new Cartesian2(cartesian.x, cartesian.y);
    }

    result.x = cartesian.x;
    result.y = cartesian.y;
    return result;
  }

  /**
   * Stores the provided instance into the provided array.
   *
   * @param {Cartesian2} value The value to pack.
   * @param {number[]|TypedArray} array The array to pack into.
   * @param {number} [startingIndex=0] The index into the array at which to start packing the elements.
   *
   * @returns {number[]|TypedArray} The array that was packed into
   */
  static pack(value, array, startingIndex) {
    //>>includeStart('debug', pragmas.debug);
    Check.typeOf.object("value", value);
    Check.defined("array", array);
    //>>includeEnd('debug');

    startingIndex = startingIndex ?? 0;

    array[startingIndex++] = value.x;
    array[startingIndex] = value.y;

    return array;
  }

  /**
   * Retrieves an instance from a packed array.
   *
   * @param {number[]|TypedArray} array The packed array.
   * @param {number} [startingIndex=0] The starting index of the element to be unpacked.
   * @param {Cartesian2} [result] The object into which to store the result.
   * @returns {Cartesian2} The modified result parameter or a new Cartesian2 instance if one was not provided.
   */
  static unpack(array, startingIndex, result) {
    //>>includeStart('debug', pragmas.debug);
    Check.defined("array", array);
    //>>includeEnd('debug');

    startingIndex = startingIndex ?? 0;

    if (!defined(result)) {
      result = new Cartesian2();
    }
    result.x = array[startingIndex++];
    result.y = array[startingIndex];
    return result;
  }

  /**
   * Flattens an array of Cartesian2s into an array of components.
   *
   * @param {Cartesian2[]} array The array of cartesians to pack.
   * @param {number[]|TypedArray} [result] The array onto which to store the result. If this is a typed array, it must have array.length * 2 components, else a {@link DeveloperError} will be thrown. If it is a regular array, it will be resized to have (array.length * 2) elements.
   * @returns {number[]|TypedArray} The packed array.
   */
  static packArray(array, result) {
    //>>includeStart('debug', pragmas.debug);
    Check.defined("array", array);
    //>>includeEnd('debug');

    const length = array.length;
    const resultLength = length * 2;
    if (!defined(result)) {
      result = new Array(resultLength);
    } else if (!Array.isArray(result) && result.length !== resultLength) {
      //>>includeStart('debug', pragmas.debug);
      throw new DeveloperError(
        "If result is a typed array, it must have exactly array.length * 2 elements",
      );
      //>>includeEnd('debug');
    } else if (result.length !== resultLength) {
      /** @type {number[]} */ (result).length = resultLength;
    }

    for (let i = 0; i < length; ++i) {
      Cartesian2.pack(array[i], result, i * 2);
    }
    return result;
  }

  /**
   * Unpacks an array of cartesian components into an array of Cartesian2s.
   *
   * @param {number[]} array The array of components to unpack.
   * @param {Cartesian2[]} [result] The array onto which to store the result.
   * @returns {Cartesian2[]} The unpacked array.
   */
  static unpackArray(array, result) {
    //>>includeStart('debug', pragmas.debug);
    Check.defined("array", array);
    Check.typeOf.number.greaterThanOrEquals("array.length", array.length, 2);
    if (array.length % 2 !== 0) {
      throw new DeveloperError("array length must be a multiple of 2.");
    }
    //>>includeEnd('debug');

    const length = array.length;
    if (!defined(result)) {
      result = new Array(length / 2);
    } else {
      result.length = length / 2;
    }

    for (let i = 0; i < length; i += 2) {
      const index = i / 2;
      result[index] = Cartesian2.unpack(array, i, result[index]);
    }
    return result;
  }

  /**
   * Computes the value of the maximum component for the supplied Cartesian.
   *
   * @param {Cartesian2} cartesian The cartesian to use.
   * @returns {number} The value of the maximum component.
   */
  static maximumComponent(cartesian) {
    //>>includeStart('debug', pragmas.debug);
    Check.typeOf.object("cartesian", cartesian);
    //>>includeEnd('debug');

    return Math.max(cartesian.x, cartesian.y);
  }

  /**
   * Computes the value of the minimum component for the supplied Cartesian.
   *
   * @param {Cartesian2} cartesian The cartesian to use.
   * @returns {number} The value of the minimum component.
   */
  static minimumComponent(cartesian) {
    //>>includeStart('debug', pragmas.debug);
    Check.typeOf.object("cartesian", cartesian);
    //>>includeEnd('debug');

    return Math.min(cartesian.x, cartesian.y);
  }

  /**
   * Compares two Cartesians and computes a Cartesian which contains the minimum components of the supplied Cartesians.
   *
   * @param {Cartesian2} first A cartesian to compare.
   * @param {Cartesian2} second A cartesian to compare.
   * @param {Cartesian2} result The object into which to store the result.
   * @returns {Cartesian2} A cartesian with the minimum components.
   */
  static minimumByComponent(first, second, result) {
    //>>includeStart('debug', pragmas.debug);
    Check.typeOf.object("first", first);
    Check.typeOf.object("second", second);
    Check.typeOf.object("result", result);
    //>>includeEnd('debug');

    result.x = Math.min(first.x, second.x);
    result.y = Math.min(first.y, second.y);

    return result;
  }

  /**
   * Compares two Cartesians and computes a Cartesian which contains the maximum components of the supplied Cartesians.
   *
   * @param {Cartesian2} first A cartesian to compare.
   * @param {Cartesian2} second A cartesian to compare.
   * @param {Cartesian2} result The object into which to store the result.
   * @returns {Cartesian2} A cartesian with the maximum components.
   */
  static maximumByComponent(first, second, result) {
    //>>includeStart('debug', pragmas.debug);
    Check.typeOf.object("first", first);
    Check.typeOf.object("second", second);
    Check.typeOf.object("result", result);
    //>>includeEnd('debug');

    result.x = Math.max(first.x, second.x);
    result.y = Math.max(first.y, second.y);
    return result;
  }

  /**
   * Constrain a value to lie between two values.
   *
   * @param {Cartesian2} value The value to clamp.
   * @param {Cartesian2} min The minimum bound.
   * @param {Cartesian2} max The maximum bound.
   * @param {Cartesian2} result The object into which to store the result.
   * @returns {Cartesian2} The clamped value such that min <= result <= max.
   */
  static clamp(value, min, max, result) {
    //>>includeStart('debug', pragmas.debug);
    Check.typeOf.object("value", value);
    Check.typeOf.object("min", min);
    Check.typeOf.object("max", max);
    Check.typeOf.object("result", result);
    //>>includeEnd('debug');

    const x = CesiumMath.clamp(value.x, min.x, max.x);
    const y = CesiumMath.clamp(value.y, min.y, max.y);

    result.x = x;
    result.y = y;

    return result;
  }

  /**
   * Computes the provided Cartesian's squared magnitude.
   *
   * @param {Cartesian2} cartesian The Cartesian instance whose squared magnitude is to be computed.
   * @returns {number} The squared magnitude.
   */
  static magnitudeSquared(cartesian) {
    //>>includeStart('debug', pragmas.debug);
    Check.typeOf.object("cartesian", cartesian);
    //>>includeEnd('debug');

    return cartesian.x * cartesian.x + cartesian.y * cartesian.y;
  }

  /**
   * Computes the Cartesian's magnitude (length).
   *
   * @param {Cartesian2} cartesian The Cartesian instance whose magnitude is to be computed.
   * @returns {number} The magnitude.
   */
  static magnitude(cartesian) {
    return Math.sqrt(Cartesian2.magnitudeSquared(cartesian));
  }

  /**
   * Computes the distance between two points.
   *
   * @param {Cartesian2} left The first point to compute the distance from.
   * @param {Cartesian2} right The second point to compute the distance to.
   * @returns {number} The distance between two points.
   *
   * @example
   * // Returns 1.0
   * const d = Cesium.Cartesian2.distance(new Cesium.Cartesian2(1.0, 0.0), new Cesium.Cartesian2(2.0, 0.0));
   */
  static distance(left, right) {
    //>>includeStart('debug', pragmas.debug);
    Check.typeOf.object("left", left);
    Check.typeOf.object("right", right);
    //>>includeEnd('debug');

    Cartesian2.subtract(left, right, distanceScratch);
    return Cartesian2.magnitude(distanceScratch);
  }

  /**
   * Computes the squared distance between two points.  Comparing squared distances
   * using this function is more efficient than comparing distances using {@link Cartesian2#distance}.
   *
   * @param {Cartesian2} left The first point to compute the distance from.
   * @param {Cartesian2} right The second point to compute the distance to.
   * @returns {number} The distance between two points.
   *
   * @example
   * // Returns 4.0, not 2.0
   * const d = Cesium.Cartesian2.distance(new Cesium.Cartesian2(1.0, 0.0), new Cesium.Cartesian2(3.0, 0.0));
   */
  static distanceSquared(left, right) {
    //>>includeStart('debug', pragmas.debug);
    Check.typeOf.object("left", left);
    Check.typeOf.object("right", right);
    //>>includeEnd('debug');

    Cartesian2.subtract(left, right, distanceScratch);
    return Cartesian2.magnitudeSquared(distanceScratch);
  }

  /**
   * Computes the normalized form of the supplied Cartesian.
   *
   * @param {Cartesian2} cartesian The Cartesian to be normalized.
   * @param {Cartesian2} result The object onto which to store the result.
   * @returns {Cartesian2} The modified result parameter.
   */
  static normalize(cartesian, result) {
    //>>includeStart('debug', pragmas.debug);
    Check.typeOf.object("cartesian", cartesian);
    Check.typeOf.object("result", result);
    //>>includeEnd('debug');

    const magnitude = Cartesian2.magnitude(cartesian);

    result.x = cartesian.x / magnitude;
    result.y = cartesian.y / magnitude;

    //>>includeStart('debug', pragmas.debug);
    if (isNaN(result.x) || isNaN(result.y)) {
      throw new DeveloperError("normalized result is not a number");
    }
    //>>includeEnd('debug');

    return result;
  }

  /**
   * Computes the dot (scalar) product of two Cartesians.
   *
   * @param {Cartesian2} left The first Cartesian.
   * @param {Cartesian2} right The second Cartesian.
   * @returns {number} The dot product.
   */
  static dot(left, right) {
    //>>includeStart('debug', pragmas.debug);
    Check.typeOf.object("left", left);
    Check.typeOf.object("right", right);
    //>>includeEnd('debug');

    return left.x * right.x + left.y * right.y;
  }

  /**
   * Computes the magnitude of the cross product that would result from implicitly setting the Z coordinate of the input vectors to 0
   *
   * @param {Cartesian2} left The first Cartesian.
   * @param {Cartesian2} right The second Cartesian.
   * @returns {number} The cross product.
   */
  static cross(left, right) {
    //>>includeStart('debug', pragmas.debug);
    Check.typeOf.object("left", left);
    Check.typeOf.object("right", right);
    //>>includeEnd('debug');

    return left.x * right.y - left.y * right.x;
  }

  /**
   * Computes the componentwise product of two Cartesians.
   *
   * @param {Cartesian2} left The first Cartesian.
   * @param {Cartesian2} right The second Cartesian.
   * @param {Cartesian2} result The object onto which to store the result.
   * @returns {Cartesian2} The modified result parameter.
   */
  static multiplyComponents(left, right, result) {
    //>>includeStart('debug', pragmas.debug);
    Check.typeOf.object("left", left);
    Check.typeOf.object("right", right);
    Check.typeOf.object("result", result);
    //>>includeEnd('debug');

    result.x = left.x * right.x;
    result.y = left.y * right.y;
    return result;
  }

  /**
   * Computes the componentwise quotient of two Cartesians.
   *
   * @param {Cartesian2} left The first Cartesian.
   * @param {Cartesian2} right The second Cartesian.
   * @param {Cartesian2} result The object onto which to store the result.
   * @returns {Cartesian2} The modified result parameter.
   */
  static divideComponents(left, right, result) {
    //>>includeStart('debug', pragmas.debug);
    Check.typeOf.object("left", left);
    Check.typeOf.object("right", right);
    Check.typeOf.object("result", result);
    //>>includeEnd('debug');

    result.x = left.x / right.x;
    result.y = left.y / right.y;
    return result;
  }

  /**
   * Computes the componentwise sum of two Cartesians.
   *
   * @param {Cartesian2} left The first Cartesian.
   * @param {Cartesian2} right The second Cartesian.
   * @param {Cartesian2} result The object onto which to store the result.
   * @returns {Cartesian2} The modified result parameter.
   */
  static add(left, right, result) {
    //>>includeStart('debug', pragmas.debug);
    Check.typeOf.object("left", left);
    Check.typeOf.object("right", right);
    Check.typeOf.object("result", result);
    //>>includeEnd('debug');

    result.x = left.x + right.x;
    result.y = left.y + right.y;
    return result;
  }

  /**
   * Computes the componentwise difference of two Cartesians.
   *
   * @param {Cartesian2} left The first Cartesian.
   * @param {Cartesian2} right The second Cartesian.
   * @param {Cartesian2} result The object onto which to store the result.
   * @returns {Cartesian2} The modified result parameter.
   */
  static subtract(left, right, result) {
    //>>includeStart('debug', pragmas.debug);
    Check.typeOf.object("left", left);
    Check.typeOf.object("right", right);
    Check.typeOf.object("result", result);
    //>>includeEnd('debug');

    result.x = left.x - right.x;
    result.y = left.y - right.y;
    return result;
  }

  /**
   * Multiplies the provided Cartesian componentwise by the provided scalar.
   *
   * @param {Cartesian2} cartesian The Cartesian to be scaled.
   * @param {number} scalar The scalar to multiply with.
   * @param {Cartesian2} result The object onto which to store the result.
   * @returns {Cartesian2} The modified result parameter.
   */
  static multiplyByScalar(cartesian, scalar, result) {
    //>>includeStart('debug', pragmas.debug);
    Check.typeOf.object("cartesian", cartesian);
    Check.typeOf.number("scalar", scalar);
    Check.typeOf.object("result", result);
    //>>includeEnd('debug');

    result.x = cartesian.x * scalar;
    result.y = cartesian.y * scalar;
    return result;
  }

  /**
   * Divides the provided Cartesian componentwise by the provided scalar.
   *
   * @param {Cartesian2} cartesian The Cartesian to be divided.
   * @param {number} scalar The scalar to divide by.
   * @param {Cartesian2} result The object onto which to store the result.
   * @returns {Cartesian2} The modified result parameter.
   */
  static divideByScalar(cartesian, scalar, result) {
    //>>includeStart('debug', pragmas.debug);
    Check.typeOf.object("cartesian", cartesian);
    Check.typeOf.number("scalar", scalar);
    Check.typeOf.object("result", result);
    //>>includeEnd('debug');

    result.x = cartesian.x / scalar;
    result.y = cartesian.y / scalar;
    return result;
  }

  /**
   * Negates the provided Cartesian.
   *
   * @param {Cartesian2} cartesian The Cartesian to be negated.
   * @param {Cartesian2} result The object onto which to store the result.
   * @returns {Cartesian2} The modified result parameter.
   */
  static negate(cartesian, result) {
    //>>includeStart('debug', pragmas.debug);
    Check.typeOf.object("cartesian", cartesian);
    Check.typeOf.object("result", result);
    //>>includeEnd('debug');

    result.x = -cartesian.x;
    result.y = -cartesian.y;
    return result;
  }

  /**
   * Computes the absolute value of the provided Cartesian.
   *
   * @param {Cartesian2} cartesian The Cartesian whose absolute value is to be computed.
   * @param {Cartesian2} result The object onto which to store the result.
   * @returns {Cartesian2} The modified result parameter.
   */
  static abs(cartesian, result) {
    //>>includeStart('debug', pragmas.debug);
    Check.typeOf.object("cartesian", cartesian);
    Check.typeOf.object("result", result);
    //>>includeEnd('debug');

    result.x = Math.abs(cartesian.x);
    result.y = Math.abs(cartesian.y);
    return result;
  }

  /**
   * Computes the linear interpolation or extrapolation at t using the provided cartesians.
   *
   * @param {Cartesian2} start The value corresponding to t at 0.0.
   * @param {Cartesian2} end The value corresponding to t at 1.0.
   * @param {number} t The point along t at which to interpolate.
   * @param {Cartesian2} result The object onto which to store the result.
   * @returns {Cartesian2} The modified result parameter.
   */
  static lerp(start, end, t, result) {
    //>>includeStart('debug', pragmas.debug);
    Check.typeOf.object("start", start);
    Check.typeOf.object("end", end);
    Check.typeOf.number("t", t);
    Check.typeOf.object("result", result);
    //>>includeEnd('debug');

    Cartesian2.multiplyByScalar(end, t, lerpScratch);
    result = Cartesian2.multiplyByScalar(start, 1.0 - t, result);
    return Cartesian2.add(lerpScratch, result, result);
  }

  /**
   * Returns the angle, in radians, between the provided Cartesians.
   *
   * @param {Cartesian2} left The first Cartesian.
   * @param {Cartesian2} right The second Cartesian.
   * @returns {number} The angle between the Cartesians.
   */
  static angleBetween(left, right) {
    //>>includeStart('debug', pragmas.debug);
    Check.typeOf.object("left", left);
    Check.typeOf.object("right", right);
    //>>includeEnd('debug');

    Cartesian2.normalize(left, angleBetweenScratch);
    Cartesian2.normalize(right, angleBetweenScratch2);
    return CesiumMath.acosClamped(
      Cartesian2.dot(angleBetweenScratch, angleBetweenScratch2),
    );
  }

  /**
   * Returns the axis that is most orthogonal to the provided Cartesian.
   *
   * @param {Cartesian2} cartesian The Cartesian on which to find the most orthogonal axis.
   * @param {Cartesian2} result The object onto which to store the result.
   * @returns {Cartesian2} The most orthogonal axis.
   */
  static mostOrthogonalAxis(cartesian, result) {
    //>>includeStart('debug', pragmas.debug);
    Check.typeOf.object("cartesian", cartesian);
    Check.typeOf.object("result", result);
    //>>includeEnd('debug');

    const f = Cartesian2.normalize(cartesian, mostOrthogonalAxisScratch);
    Cartesian2.abs(f, f);

    if (f.x <= f.y) {
      result = Cartesian2.clone(Cartesian2.UNIT_X, result);
    } else {
      result = Cartesian2.clone(Cartesian2.UNIT_Y, result);
    }

    return result;
  }

  /**
   * Compares the provided Cartesians componentwise and returns
   * <code>true</code> if they are equal, <code>false</code> otherwise.
   *
   * @param {Cartesian2} [left] The first Cartesian.
   * @param {Cartesian2} [right] The second Cartesian.
   * @returns {boolean} <code>true</code> if left and right are equal, <code>false</code> otherwise.
   */
  static equals(left, right) {
    return (
      left === right ||
      (defined(left) &&
        defined(right) &&
        left.x === right.x &&
        left.y === right.y)
    );
  }

  /**
   * @param {Cartesian2} cartesian
   * @param {number[]} array
   * @param {number} offset
   * @private
   */
  static equalsArray(cartesian, array, offset) {
    return cartesian.x === array[offset] && cartesian.y === array[offset + 1];
  }

  /**
   * Compares the provided Cartesians componentwise and returns
   * <code>true</code> if they pass an absolute or relative tolerance test,
   * <code>false</code> otherwise.
   *
   * @param {Cartesian2} [left] The first Cartesian.
   * @param {Cartesian2} [right] The second Cartesian.
   * @param {number} [relativeEpsilon=0] The relative epsilon tolerance to use for equality testing.
   * @param {number} [absoluteEpsilon=relativeEpsilon] The absolute epsilon tolerance to use for equality testing.
   * @returns {boolean} <code>true</code> if left and right are within the provided epsilon, <code>false</code> otherwise.
   */
  static equalsEpsilon(left, right, relativeEpsilon, absoluteEpsilon) {
    return (
      left === right ||
      (defined(left) &&
        defined(right) &&
        CesiumMath.equalsEpsilon(
          left.x,
          right.x,
          relativeEpsilon,
          absoluteEpsilon,
        ) &&
        CesiumMath.equalsEpsilon(
          left.y,
          right.y,
          relativeEpsilon,
          absoluteEpsilon,
        ))
    );
  }

  /**
   * Duplicates this Cartesian2 instance.
   *
   * @param {Cartesian2} [result] The object onto which to store the result.
   * @returns {Cartesian2} The modified result parameter or a new Cartesian2 instance if one was not provided.
   */
  clone(result) {
    return Cartesian2.clone(this, result);
  }

  /**
   * Compares this Cartesian against the provided Cartesian componentwise and returns
   * <code>true</code> if they are equal, <code>false</code> otherwise.
   *
   * @param {Cartesian2} [right] The right hand side Cartesian.
   * @returns {boolean} <code>true</code> if they are equal, <code>false</code> otherwise.
   */
  equals(right) {
    return Cartesian2.equals(this, right);
  }

  /**
   * Compares this Cartesian against the provided Cartesian componentwise and returns
   * <code>true</code> if they pass an absolute or relative tolerance test,
   * <code>false</code> otherwise.
   *
   * @param {Cartesian2} [right] The right hand side Cartesian.
   * @param {number} [relativeEpsilon=0] The relative epsilon tolerance to use for equality testing.
   * @param {number} [absoluteEpsilon=relativeEpsilon] The absolute epsilon tolerance to use for equality testing.
   * @returns {boolean} <code>true</code> if they are within the provided epsilon, <code>false</code> otherwise.
   */
  equalsEpsilon(right, relativeEpsilon, absoluteEpsilon) {
    return Cartesian2.equalsEpsilon(
      this,
      right,
      relativeEpsilon,
      absoluteEpsilon,
    );
  }

  /**
   * Creates a string representing this Cartesian in the format '(x, y)'.
   *
   * @returns {string} A string representing the provided Cartesian in the format '(x, y)'.
   */
  toString() {
    return `(${this.x}, ${this.y})`;
  }
}

/**
 * Creates a Cartesian2 instance from an existing Cartesian3.  This simply takes the
 * x and y properties of the Cartesian3 and drops z.
 * @function
 *
 * @param {Cartesian3} cartesian The Cartesian3 instance to create a Cartesian2 instance from.
 * @param {Cartesian2} [result] The object onto which to store the result.
 * @returns {Cartesian2} The modified result parameter or a new Cartesian2 instance if one was not provided.
 */
Cartesian2.fromCartesian3 = Cartesian2.clone;

/**
 * Creates a Cartesian2 instance from an existing Cartesian4.  This simply takes the
 * x and y properties of the Cartesian4 and drops z and w.
 * @function
 *
 * @param {Cartesian4} cartesian The Cartesian4 instance to create a Cartesian2 instance from.
 * @param {Cartesian2} [result] The object onto which to store the result.
 * @returns {Cartesian2} The modified result parameter or a new Cartesian2 instance if one was not provided.
 */
Cartesian2.fromCartesian4 = Cartesian2.clone;

/**
 * The number of elements used to pack the object into an array.
 * @type {number}
 */
Cartesian2.packedLength = 2;

/**
 * Creates a Cartesian2 from two consecutive elements in an array.
 * @function
 *
 * @param {number[]} array The array whose two consecutive elements correspond to the x and y components, respectively.
 * @param {number} [startingIndex=0] The offset into the array of the first element, which corresponds to the x component.
 * @param {Cartesian2} [result] The object onto which to store the result.
 * @returns {Cartesian2} The modified result parameter or a new Cartesian2 instance if one was not provided.
 *
 * @example
 * // Create a Cartesian2 with (1.0, 2.0)
 * const v = [1.0, 2.0];
 * const p = Cesium.Cartesian2.fromArray(v);
 *
 * // Create a Cartesian2 with (1.0, 2.0) using an offset into an array
 * const v2 = [0.0, 0.0, 1.0, 2.0];
 * const p2 = Cesium.Cartesian2.fromArray(v2, 2);
 */
Cartesian2.fromArray = Cartesian2.unpack;

const distanceScratch = new Cartesian2();

const lerpScratch = new Cartesian2();

const angleBetweenScratch = new Cartesian2();
const angleBetweenScratch2 = new Cartesian2();

const mostOrthogonalAxisScratch = new Cartesian2();

/**
 * An immutable Cartesian2 instance initialized to (0.0, 0.0).
 *
 * @type {Cartesian2}
 * @constant
 */
Cartesian2.ZERO = Object.freeze(new Cartesian2(0.0, 0.0));

/**
 * An immutable Cartesian2 instance initialized to (1.0, 1.0).
 *
 * @type {Cartesian2}
 * @constant
 */
Cartesian2.ONE = Object.freeze(new Cartesian2(1.0, 1.0));

/**
 * An immutable Cartesian2 instance initialized to (1.0, 0.0).
 *
 * @type {Cartesian2}
 * @constant
 */
Cartesian2.UNIT_X = Object.freeze(new Cartesian2(1.0, 0.0));

/**
 * An immutable Cartesian2 instance initialized to (0.0, 1.0).
 *
 * @type {Cartesian2}
 * @constant
 */
Cartesian2.UNIT_Y = Object.freeze(new Cartesian2(0.0, 1.0));

export default Cartesian2;