191 lines
8.2 KiB
JavaScript
191 lines
8.2 KiB
JavaScript
var EllipseGeometryLibraryEx = (function () {
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var EllipseGeometryLibrary = {};
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function pointOnEllipsoid(theta, rotation, northVec, eastVec, aSqr, ab, bSqr, mag, unitPos, result) {
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var rotAxis = new Cesium.Cartesian3();
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var tempVec = new Cesium.Cartesian3();
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var unitQuat = new Cesium.Quaternion();
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var rotMtx = new Cesium.Matrix3();
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var azimuth = theta + rotation;
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Cesium.Cartesian3.multiplyByScalar(eastVec, Math.cos(azimuth), rotAxis);
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Cesium.Cartesian3.multiplyByScalar(northVec, Math.sin(azimuth), tempVec);
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Cesium.Cartesian3.add(rotAxis, tempVec, rotAxis);
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var cosThetaSquared = Math.cos(theta);
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cosThetaSquared = cosThetaSquared * cosThetaSquared;
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var sinThetaSquared = Math.sin(theta);
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sinThetaSquared = sinThetaSquared * sinThetaSquared;
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var radius = ab / Math.sqrt(bSqr * cosThetaSquared + aSqr * sinThetaSquared);
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var angle = radius / mag;
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// Create the quaternion to rotate the position vector to the boundary of the ellipse.
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Cesium.Quaternion.fromAxisAngle(rotAxis, angle, unitQuat);
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Cesium.Matrix3.fromQuaternion(unitQuat, rotMtx);
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Cesium.Matrix3.multiplyByVector(rotMtx, unitPos, result);
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Cesium.Cartesian3.normalize(result, result);
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Cesium.Cartesian3.multiplyByScalar(result, mag, result);
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return result;
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}
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/**
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* Returns the positions raised to the given heights
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* @private
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*/
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EllipseGeometryLibrary.raisePositionsToHeight = function (positions, options, extrude) {
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var scratchCartesian1 = new Cesium.Cartesian3();
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var scratchCartesian2 = new Cesium.Cartesian3();
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var scratchCartesian3 = new Cesium.Cartesian3();
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var scratchNormal = new Cesium.Cartesian3();
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var ellipsoid = options.ellipsoid;
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var height = options.height;
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var extrudedHeight = options.extrudedHeight;
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var size = (extrude) ? positions.length / 3 * 2 : positions.length / 3;
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var finalPositions = new Float64Array(size * 3);
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var length = positions.length;
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var bottomOffset = (extrude) ? length : 0;
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for (var i = 0; i < length; i += 3) {
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var i1 = i + 1;
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var i2 = i + 2;
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var position = Cesium.Cartesian3.fromArray(positions, i, scratchCartesian1);
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ellipsoid.scaleToGeodeticSurface(position, position);
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var extrudedPosition = Cesium.Cartesian3.clone(position, scratchCartesian2);
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var normal = ellipsoid.geodeticSurfaceNormal(position, scratchNormal);
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var scaledNormal = Cesium.Cartesian3.multiplyByScalar(normal, height, scratchCartesian3);
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Cesium.Cartesian3.add(position, scaledNormal, position);
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if (extrude) {
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Cesium.Cartesian3.multiplyByScalar(normal, extrudedHeight, scaledNormal);
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Cesium.Cartesian3.add(extrudedPosition, scaledNormal, extrudedPosition);
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finalPositions[i + bottomOffset] = extrudedPosition.x;
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finalPositions[i1 + bottomOffset] = extrudedPosition.y;
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finalPositions[i2 + bottomOffset] = extrudedPosition.z;
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}
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finalPositions[i] = position.x;
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finalPositions[i1] = position.y;
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finalPositions[i2] = position.z;
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}
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return finalPositions;
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};
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/**
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* options.semiMinorAxis：短半轴
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* options.semiMajorAxis：长半轴
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* options.rotation：旋转角度 弧度
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* options.center：中心点 笛卡尔坐标
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* options.granularity：粒度 弧度
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* Returns an array of positions that make up the ellipse.
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* @private
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*/
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EllipseGeometryLibrary.computeEllipseEdgePositions = function (options) {
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var unitPosScratch = new Cesium.Cartesian3();
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var eastVecScratch = new Cesium.Cartesian3();
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var northVecScratch = new Cesium.Cartesian3();
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var scratchCartesian1 = new Cesium.Cartesian3();
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var semiMinorAxis = options.semiMinorAxis;
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var semiMajorAxis = options.semiMajorAxis;
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var rotation = options.rotation;//法线
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var center = options.center;
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var granularity = options.granularity && (typeof options.granularity === "number") ? options.granularity : (Math.PI / 180.0);// 角度间隔
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if (granularity > Math.PI / 12.0) { granularity = Math.PI / 12.0; }//最小分24
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if (granularity < Math.PI / 180.0) { granularity = Math.PI / 180.0; }//最大分360
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var aSqr = semiMinorAxis * semiMinorAxis;
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var bSqr = semiMajorAxis * semiMajorAxis;
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var ab = semiMajorAxis * semiMinorAxis;
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var mag = Cesium.Cartesian3.magnitude(center);//
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var unitPos = Cesium.Cartesian3.normalize(center, unitPosScratch);
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var eastVec = Cesium.Cartesian3.cross(Cesium.Cartesian3.UNIT_Z, center, eastVecScratch);
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eastVec = Cesium.Cartesian3.normalize(eastVec, eastVec);
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var northVec = Cesium.Cartesian3.cross(unitPos, eastVec, northVecScratch);
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var numPts = Math.ceil(Cesium.Math.PI*2 / granularity);
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var deltaTheta = granularity;
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var theta = 0;
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var position = scratchCartesian1;
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var i;
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var outerIndex = 0;
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var outerPositions = [];
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for (i = 0; i < numPts; i++) {
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theta = i * deltaTheta;
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position = pointOnEllipsoid(theta, rotation, northVec, eastVec, aSqr, ab, bSqr, mag, unitPos, position);
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outerPositions[outerIndex++] = position.x;
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outerPositions[outerIndex++] = position.y;
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outerPositions[outerIndex++] = position.z;
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}
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var r = {};
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r.numPts = numPts;
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r.outerPositions = outerPositions;
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return r;
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};
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/**
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* options.semiMinorAxis：短半轴
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* options.semiMajorAxis：长半轴
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* options.rotation：旋转角度 弧度
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* options.center：中心点 笛卡尔坐标
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* options.granularity：粒度 弧度
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* options.angle：角度 弧度
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* Returns an array of positions that make up the ellipse.
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* @private
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*/
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EllipseGeometryLibrary.computeSectorEdgePositions = function (options) {
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var unitPosScratch = new Cesium.Cartesian3();
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var eastVecScratch = new Cesium.Cartesian3();
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var northVecScratch = new Cesium.Cartesian3();
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var scratchCartesian1 = new Cesium.Cartesian3();
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var semiMinorAxis = options.semiMinorAxis;
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var semiMajorAxis = options.semiMajorAxis;
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var rotation = options.rotation;
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var angle = options.angle ? options.angle : Math.PI * 2.0;
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var center = options.center;
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var granularity = options.granularity && (typeof options.granularity === "number") ? options.granularity : (Math.PI / 180.0);// 角度间隔
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if (granularity > Math.PI / 12.0) { granularity = Math.PI / 12.0; }//最小分24
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if (granularity < Math.PI / 180.0) { granularity = Math.PI / 180.0; }//最大分360
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var aSqr = semiMinorAxis * semiMinorAxis;
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var bSqr = semiMajorAxis * semiMajorAxis;
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var ab = semiMajorAxis * semiMinorAxis;
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var mag = Cesium.Cartesian3.magnitude(center);//
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var unitPos = Cesium.Cartesian3.normalize(center, unitPosScratch);
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var eastVec = Cesium.Cartesian3.cross(Cesium.Cartesian3.UNIT_Z, center, eastVecScratch);
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eastVec = Cesium.Cartesian3.normalize(eastVec, eastVec);
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var northVec = Cesium.Cartesian3.cross(unitPos, eastVec, northVecScratch);
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var numPts = Math.ceil(angle / granularity);//Math.ceil(Cesium.Math.PI * 2 / granularity);
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var deltaTheta = granularity;
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var theta = 0;
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var position = scratchCartesian1;
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var i;
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var outerIndex = 0;
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var outerPositions = [];
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for (i = 0; i < numPts; i++) {
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theta = i * deltaTheta;
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position = pointOnEllipsoid(theta, rotation, northVec, eastVec, aSqr, ab, bSqr, mag, unitPos, position);
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outerPositions[outerIndex++] = position.x;
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outerPositions[outerIndex++] = position.y;
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outerPositions[outerIndex++] = position.z;
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}
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var r = {};
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r.numPts = numPts;
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r.outerPositions = outerPositions;
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return r;
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};
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return EllipseGeometryLibrary;
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})(); |