import Cartesian3 from "./Cartesian3.js";
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import defined from "./defined.js";
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import Iau2000Orientation from "./Iau2000Orientation.js";
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import JulianDate from "./JulianDate.js";
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import CesiumMath from "./Math.js";
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import Matrix3 from "./Matrix3.js";
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import Quaternion from "./Quaternion.js";
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/**
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* The Axes representing the orientation of a Globe as represented by the data
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* from the IAU/IAG Working Group reports on rotational elements.
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* @alias IauOrientationAxes
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* @constructor
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*
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* @param {IauOrientationAxes.ComputeFunction} [computeFunction] The function that computes the {@link IauOrientationParameters} given a {@link JulianDate}.
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*
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* @see Iau2000Orientation
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*
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* @private
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*/
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function IauOrientationAxes(computeFunction) {
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if (!defined(computeFunction) || typeof computeFunction !== "function") {
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computeFunction = Iau2000Orientation.ComputeMoon;
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}
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this._computeFunction = computeFunction;
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}
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var xAxisScratch = new Cartesian3();
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var yAxisScratch = new Cartesian3();
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var zAxisScratch = new Cartesian3();
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function computeRotationMatrix(alpha, delta, result) {
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var xAxis = xAxisScratch;
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xAxis.x = Math.cos(alpha + CesiumMath.PI_OVER_TWO);
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xAxis.y = Math.sin(alpha + CesiumMath.PI_OVER_TWO);
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xAxis.z = 0.0;
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var cosDec = Math.cos(delta);
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var zAxis = zAxisScratch;
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zAxis.x = cosDec * Math.cos(alpha);
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zAxis.y = cosDec * Math.sin(alpha);
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zAxis.z = Math.sin(delta);
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var yAxis = Cartesian3.cross(zAxis, xAxis, yAxisScratch);
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if (!defined(result)) {
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result = new Matrix3();
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}
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result[0] = xAxis.x;
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result[1] = yAxis.x;
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result[2] = zAxis.x;
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result[3] = xAxis.y;
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result[4] = yAxis.y;
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result[5] = zAxis.y;
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result[6] = xAxis.z;
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result[7] = yAxis.z;
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result[8] = zAxis.z;
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return result;
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}
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var rotMtxScratch = new Matrix3();
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var quatScratch = new Quaternion();
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/**
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* Computes a rotation from ICRF to a Globe's Fixed axes.
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*
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* @param {JulianDate} date The date to evaluate the matrix.
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* @param {Matrix3} result The object onto which to store the result.
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* @returns {Matrix3} The modified result parameter or a new instance of the rotation from ICRF to Fixed.
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*/
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IauOrientationAxes.prototype.evaluate = function (date, result) {
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if (!defined(date)) {
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date = JulianDate.now();
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}
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var alphaDeltaW = this._computeFunction(date);
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var precMtx = computeRotationMatrix(
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alphaDeltaW.rightAscension,
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alphaDeltaW.declination,
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result
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);
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var rot = CesiumMath.zeroToTwoPi(alphaDeltaW.rotation);
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var quat = Quaternion.fromAxisAngle(Cartesian3.UNIT_Z, rot, quatScratch);
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var rotMtx = Matrix3.fromQuaternion(
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Quaternion.conjugate(quat, quat),
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rotMtxScratch
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);
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var cbi2cbf = Matrix3.multiply(rotMtx, precMtx, precMtx);
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return cbi2cbf;
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};
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/**
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* A function that computes the {@link IauOrientationParameters} for a {@link JulianDate}.
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* @callback IauOrientationAxes.ComputeFunction
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* @param {JulianDate} date The date to evaluate the parameters.
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* @returns {IauOrientationParameters} The orientation parameters.
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* @private
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*/
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export default IauOrientationAxes;
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