three.js/examples/jsm/utils/MathUtils.js

/**
 * @author WestLangley / http://github.com/WestLangley
 * @author thezwap / http://github.com/thezwap
 */



var MathUtils = {


	/**
	 * @param {Quaternion} q
	 * @param {number} a
	 * @param {number} b
	 * @param {number} c
	 * @param {string} order
	 */
	setQuaternionFromProperEuler: function (q, a, b, c, order) {

		// Intrinsic Proper Euler Angles - see https://en.wikipedia.org/wiki/Euler_angles

		// rotations are applied to the axes in the order specified by 'order'
		// rotation by angle 'a' is applied first, then by angle 'b', then by angle 'c'
		// angles are in radians

		var cos = Math.cos;
		var sin = Math.sin;

		var c2 = cos(b / 2);
		var s2 = sin(b / 2);

		var c13 = cos((a + c) / 2);
		var s13 = sin((a + c) / 2);

		var c1_3 = cos((a - c) / 2);
		var s1_3 = sin((a - c) / 2);

		var c3_1 = cos((c - a) / 2);
		var s3_1 = sin((c - a) / 2);

		if (order === 'XYX') {

			q.set(c2 * s13, s2 * c1_3, s2 * s1_3, c2 * c13);

		} else if (order === 'YZY') {

			q.set(s2 * s1_3, c2 * s13, s2 * c1_3, c2 * c13);

		} else if (order === 'ZXZ') {

			q.set(s2 * c1_3, s2 * s1_3, c2 * s13, c2 * c13);

		} else if (order === 'XZX') {

			q.set(c2 * s13, s2 * s3_1, s2 * c3_1, c2 * c13);

		} else if (order === 'YXY') {

			q.set(s2 * c3_1, c2 * s13, s2 * s3_1, c2 * c13);

		} else if (order === 'ZYZ') {

			q.set(s2 * s3_1, s2 * c3_1, c2 * s13, c2 * c13);

		} else {

			console.warn('THREE.MathUtils: .setQuaternionFromProperEuler() encountered an unknown order.');

		}

	}

};

export {MathUtils};