text: import Cartesian3 from "./Cartesian3.js";
  import CesiumMath from "./Math.js";
  import Matrix3 from "./Matrix3.js";
  import Quaternion from "./Quaternion.js";
  
  var EllipseGeometryLibrary = {};
  
  var rotAxis = new Cartesian3();
  var tempVec = new Cartesian3();
  var unitQuat = new Quaternion();
  var rotMtx = new Matrix3();
  
  function pointOnEllipsoid(
    theta,
    rotation,
    northVec,
    eastVec,
    aSqr,
    ab,
    bSqr,
    mag,
    unitPos,
    result
  ) {
    var azimuth = theta + rotation;
  
    Cartesian3.multiplyByScalar(eastVec, Math.cos(azimuth), rotAxis);
    Cartesian3.multiplyByScalar(northVec, Math.sin(azimuth), tempVec);
    Cartesian3.add(rotAxis, tempVec, rotAxis);
  
    var cosThetaSquared = Math.cos(theta);
    cosThetaSquared = cosThetaSquared * cosThetaSquared;
  
    var sinThetaSquared = Math.sin(theta);
    sinThetaSquared = sinThetaSquared * sinThetaSquared;
  
    var radius = ab / Math.sqrt(bSqr * cosThetaSquared + aSqr * sinThetaSquared);
    var angle = radius / mag;
  
    // Create the quaternion to rotate the position vector to the boundary of the ellipse.
    Quaternion.fromAxisAngle(rotAxis, angle, unitQuat);
    Matrix3.fromQuaternion(unitQuat, rotMtx);
  
    Matrix3.multiplyByVector(rotMtx, unitPos, result);
    Cartesian3.normalize(result, result);
    Cartesian3.multiplyByScalar(result, mag, result);
    return result;
  }
  
  var scratchCartesian1 = new Cartesian3();
  var scratchCartesian2 = new Cartesian3();
  var scratchCartesian3 = new Cartesian3();
  var scratchNormal = new Cartesian3();
  /**
   * Returns the positions raised to the given heights
   * @private
   */
  EllipseGeometryLibrary.raisePositionsToHeight = function (
    positions,
    options,
    extrude
  ) {
    var ellipsoid = options.ellipsoid;
    var height = options.height;
    var extrudedHeight = options.extrudedHeight;
    var size = extrude ? (positions.length / 3) * 2 : positions.length / 3;
  
    var finalPositions = new Float64Array(size * 3);
  
    var length = positions.length;
    var bottomOffset = extrude ? length : 0;
    for (var i = 0; i < length; i += 3) {
      var i1 = i + 1;
      var i2 = i + 2;
  
      var position = Cartesian3.fromArray(positions, i, scratchCartesian1);
      ellipsoid.scaleToGeodeticSurface(position, position);
  
      var extrudedPosition = Cartesian3.clone(position, scratchCartesian2);
      var normal = ellipsoid.geodeticSurfaceNormal(position, scratchNormal);
      var scaledNormal = Cartesian3.multiplyByScalar(
        normal,
        height,
        scratchCartesian3
      );
      Cartesian3.add(position, scaledNormal, position);
  
      if (extrude) {
        Cartesian3.multiplyByScalar(normal, extrudedHeight, scaledNormal);
        Cartesian3.add(extrudedPosition, scaledNormal, extrudedPosition);
  
        finalPositions[i + bottomOffset] = extrudedPosition.x;
        finalPositions[i1 + bottomOffset] = extrudedPosition.y;
        finalPositions[i2 + bottomOffset] = extrudedPosition.z;
      }
  
      finalPositions[i] = position.x;
      finalPositions[i1] = position.y;
      finalPositions[i2] = position.z;
    }
  
    return finalPositions;
  };
  
  var unitPosScratch = new Cartesian3();
  var eastVecScratch = new Cartesian3();
  var northVecScratch = new Cartesian3();
  /**
   * Returns an array of positions that make up the ellipse.
   * @private
   */
  EllipseGeometryLibrary.computeEllipsePositions = function (
    options,
    addFillPositions,
    addEdgePositions
  ) {
    var semiMinorAxis = options.semiMinorAxis;
    var semiMajorAxis = options.semiMajorAxis;
    var rotation = options.rotation;
    var center = options.center;
  
    // Computing the arc-length of the ellipse is too expensive to be practical. Estimating it using the
    // arc length of the sphere is too inaccurate and creates sharp edges when either the semi-major or
    // semi-minor axis is much bigger than the other. Instead, scale the angle delta to make
    // the distance along the ellipse boundary more closely match the granularity.
    var granularity = options.granularity * 8.0;
  
    var aSqr = semiMinorAxis * semiMinorAxis;
    var bSqr = semiMajorAxis * semiMajorAxis;
    var ab = semiMajorAxis * semiMinorAxis;
  
    var mag = Cartesian3.magnitude(center);
  
    var unitPos = Cartesian3.normalize(center, unitPosScratch);
    var eastVec = Cartesian3.cross(Cartesian3.UNIT_Z, center, eastVecScratch);
    eastVec = Cartesian3.normalize(eastVec, eastVec);
    var northVec = Cartesian3.cross(unitPos, eastVec, northVecScratch);
  
    // The number of points in the first quadrant
    var numPts = 1 + Math.ceil(CesiumMath.PI_OVER_TWO / granularity);
  
    var deltaTheta = CesiumMath.PI_OVER_TWO / (numPts - 1);
    var theta = CesiumMath.PI_OVER_TWO - numPts * deltaTheta;
    if (theta < 0.0) {
      numPts -= Math.ceil(Math.abs(theta) / deltaTheta);
    }
  
    // If the number of points were three, the ellipse
    // would be tessellated like below:
    //
    //         *---*
    //       / | \ | \
    //     *---*---*---*
    //   / | \ | \ | \ | \
    //  / .*---*---*---*. \
    // * ` | \ | \ | \ | `*
    //  \`.*---*---*---*.`/
    //   \ | \ | \ | \ | /
    //     *---*---*---*
    //       \ | \ | /
    //         *---*
    // The first and last column have one position and fan to connect to the adjacent column.
    // Each other vertical column contains an even number of positions.
    var size = 2 * (numPts * (numPts + 2));
    var positions = addFillPositions ? new Array(size * 3) : undefined;
    var positionIndex = 0;
    var position = scratchCartesian1;
    var reflectedPosition = scratchCartesian2;
  
    var outerPositionsLength = numPts * 4 * 3;
    var outerRightIndex = outerPositionsLength - 1;
    var outerLeftIndex = 0;
    var outerPositions = addEdgePositions
      ? new Array(outerPositionsLength)
      : undefined;
  
    var i;
    var j;
    var numInterior;
    var t;
    var interiorPosition;
  
    // Compute points in the 'eastern' half of the ellipse
    theta = CesiumMath.PI_OVER_TWO;
    position = pointOnEllipsoid(
      theta,
      rotation,
      northVec,
      eastVec,
      aSqr,
      ab,
      bSqr,
      mag,
      unitPos,
      position
    );
    if (addFillPositions) {
      positions[positionIndex++] = position.x;
      positions[positionIndex++] = position.y;
      positions[positionIndex++] = position.z;
    }
    if (addEdgePositions) {
      outerPositions[outerRightIndex--] = position.z;
      outerPositions[outerRightIndex--] = position.y;
      outerPositions[outerRightIndex--] = position.x;
    }
    theta = CesiumMath.PI_OVER_TWO - deltaTheta;
    for (i = 1; i < numPts + 1; ++i) {
      position = pointOnEllipsoid(
        theta,
        rotation,
        northVec,
        eastVec,
        aSqr,
        ab,
        bSqr,
        mag,
        unitPos,
        position
      );
      reflectedPosition = pointOnEllipsoid(
        Math.PI - theta,
        rotation,
        northVec,
        eastVec,
        aSqr,
        ab,
        bSqr,
        mag,
        unitPos,
        reflectedPosition
      );
  
      if (addFillPositions) {
        positions[positionIndex++] = position.x;
        positions[positionIndex++] = position.y;
        positions[positionIndex++] = position.z;
  
        numInterior = 2 * i + 2;
        for (j = 1; j < numInterior - 1; ++j) {
          t = j / (numInterior - 1);
          interiorPosition = Cartesian3.lerp(
            position,
            reflectedPosition,
            t,
            scratchCartesian3
          );
          positions[positionIndex++] = interiorPosition.x;
          positions[positionIndex++] = interiorPosition.y;
          positions[positionIndex++] = interiorPosition.z;
        }
  
        positions[positionIndex++] = reflectedPosition.x;
        positions[positionIndex++] = reflectedPosition.y;
        positions[positionIndex++] = reflectedPosition.z;
      }
  
      if (addEdgePositions) {
        outerPositions[outerRightIndex--] = position.z;
        outerPositions[outerRightIndex--] = position.y;
        outerPositions[outerRightIndex--] = position.x;
        outerPositions[outerLeftIndex++] = reflectedPosition.x;
        outerPositions[outerLeftIndex++] = reflectedPosition.y;
        outerPositions[outerLeftIndex++] = reflectedPosition.z;
      }
  
      theta = CesiumMath.PI_OVER_TWO - (i + 1) * deltaTheta;
    }
  
    // Compute points in the 'western' half of the ellipse
    for (i = numPts; i > 1; --i) {
      theta = CesiumMath.PI_OVER_TWO - (i - 1) * deltaTheta;
  
      position = pointOnEllipsoid(
        -theta,
        rotation,
        northVec,
        eastVec,
        aSqr,
        ab,
        bSqr,
        mag,
        unitPos,
        position
      );
      reflectedPosition = pointOnEllipsoid(
        theta + Math.PI,
        rotation,
        northVec,
        eastVec,
        aSqr,
        ab,
        bSqr,
        mag,
        unitPos,
        reflectedPosition
      );
  
      if (addFillPositions) {
        positions[positionIndex++] = position.x;
        positions[positionIndex++] = position.y;
        positions[positionIndex++] = position.z;
  
        numInterior = 2 * (i - 1) + 2;
        for (j = 1; j < numInterior - 1; ++j) {
          t = j / (numInterior - 1);
          interiorPosition = Cartesian3.lerp(
            position,
            reflectedPosition,
            t,
            scratchCartesian3
          );
          positions[positionIndex++] = interiorPosition.x;
          positions[positionIndex++] = interiorPosition.y;
          positions[positionIndex++] = interiorPosition.z;
        }
  
        positions[positionIndex++] = reflectedPosition.x;
        positions[positionIndex++] = reflectedPosition.y;
        positions[positionIndex++] = reflectedPosition.z;
      }
  
      if (addEdgePositions) {
        outerPositions[outerRightIndex--] = position.z;
        outerPositions[outerRightIndex--] = position.y;
        outerPositions[outerRightIndex--] = position.x;
        outerPositions[outerLeftIndex++] = reflectedPosition.x;
        outerPositions[outerLeftIndex++] = reflectedPosition.y;
        outerPositions[outerLeftIndex++] = reflectedPosition.z;
      }
    }
  
    theta = CesiumMath.PI_OVER_TWO;
    position = pointOnEllipsoid(
      -theta,
      rotation,
      northVec,
      eastVec,
      aSqr,
      ab,
      bSqr,
      mag,
      unitPos,
      position
    );
  
    var r = {};
    if (addFillPositions) {
      positions[positionIndex++] = position.x;
      positions[positionIndex++] = position.y;
      positions[positionIndex++] = position.z;
      r.positions = positions;
      r.numPts = numPts;
    }
    if (addEdgePositions) {
      outerPositions[outerRightIndex--] = position.z;
      outerPositions[outerRightIndex--] = position.y;
      outerPositions[outerRightIndex--] = position.x;
      r.outerPositions = outerPositions;
    }
  
    return r;
  };
  export default EllipseGeometryLibrary;
  