cesium
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CesiumJS is a JavaScript library for creating 3D globes and 2D maps in a web browser without a plugin.
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JavaScript
define([
'./BoundingSphere',
'./Cartesian3',
'./ComponentDatatype',
'./defaultValue',
'./defined',
'./DeveloperError',
'./EllipseGeometryLibrary',
'./Ellipsoid',
'./Geometry',
'./GeometryAttribute',
'./GeometryAttributes',
'./IndexDatatype',
'./Math',
'./PrimitiveType'
], function(
BoundingSphere,
Cartesian3,
ComponentDatatype,
defaultValue,
defined,
DeveloperError,
EllipseGeometryLibrary,
Ellipsoid,
Geometry,
GeometryAttribute,
GeometryAttributes,
IndexDatatype,
CesiumMath,
PrimitiveType) {
'use strict';
var scratchCartesian1 = new Cartesian3();
var boundingSphereCenter = new Cartesian3();
function computeEllipse(options) {
var center = options.center;
boundingSphereCenter = Cartesian3.multiplyByScalar(options.ellipsoid.geodeticSurfaceNormal(center, boundingSphereCenter), options.height, boundingSphereCenter);
boundingSphereCenter = Cartesian3.add(center, boundingSphereCenter, boundingSphereCenter);
var boundingSphere = new BoundingSphere(boundingSphereCenter, options.semiMajorAxis);
var positions = EllipseGeometryLibrary.computeEllipsePositions(options, false, true).outerPositions;
var attributes = new GeometryAttributes({
position: new GeometryAttribute({
componentDatatype : ComponentDatatype.DOUBLE,
componentsPerAttribute : 3,
values : EllipseGeometryLibrary.raisePositionsToHeight(positions, options, false)
})
});
var length = positions.length / 3;
var indices = IndexDatatype.createTypedArray(length, length * 2);
var index = 0;
for ( var i = 0; i < length; ++i) {
indices[index++] = i;
indices[index++] = (i + 1) % length;
}
return {
boundingSphere : boundingSphere,
attributes : attributes,
indices : indices
};
}
var topBoundingSphere = new BoundingSphere();
var bottomBoundingSphere = new BoundingSphere();
function computeExtrudedEllipse(options) {
var center = options.center;
var ellipsoid = options.ellipsoid;
var semiMajorAxis = options.semiMajorAxis;
var scaledNormal = Cartesian3.multiplyByScalar(ellipsoid.geodeticSurfaceNormal(center, scratchCartesian1), options.height, scratchCartesian1);
topBoundingSphere.center = Cartesian3.add(center, scaledNormal, topBoundingSphere.center);
topBoundingSphere.radius = semiMajorAxis;
scaledNormal = Cartesian3.multiplyByScalar(ellipsoid.geodeticSurfaceNormal(center, scaledNormal), options.extrudedHeight, scaledNormal);
bottomBoundingSphere.center = Cartesian3.add(center, scaledNormal, bottomBoundingSphere.center);
bottomBoundingSphere.radius = semiMajorAxis;
var positions = EllipseGeometryLibrary.computeEllipsePositions(options, false, true).outerPositions;
var attributes = new GeometryAttributes({
position: new GeometryAttribute({
componentDatatype : ComponentDatatype.DOUBLE,
componentsPerAttribute : 3,
values : EllipseGeometryLibrary.raisePositionsToHeight(positions, options, true)
})
});
positions = attributes.position.values;
var boundingSphere = BoundingSphere.union(topBoundingSphere, bottomBoundingSphere);
var length = positions.length/3;
var numberOfVerticalLines = defaultValue(options.numberOfVerticalLines, 16);
numberOfVerticalLines = CesiumMath.clamp(numberOfVerticalLines, 0, length/2);
var indices = IndexDatatype.createTypedArray(length, length * 2 + numberOfVerticalLines * 2);
length /= 2;
var index = 0;
var i;
for (i = 0; i < length; ++i) {
indices[index++] = i;
indices[index++] = (i + 1) % length;
indices[index++] = i + length;
indices[index++] = ((i + 1) % length) + length;
}
var numSide;
if (numberOfVerticalLines > 0) {
var numSideLines = Math.min(numberOfVerticalLines, length);
numSide = Math.round(length / numSideLines);
var maxI = Math.min(numSide * numberOfVerticalLines, length);
for (i = 0; i < maxI; i += numSide) {
indices[index++] = i;
indices[index++] = i + length;
}
}
return {
boundingSphere : boundingSphere,
attributes : attributes,
indices : indices
};
}
/**
* A description of the outline of an ellipse on an ellipsoid.
*
* @alias EllipseOutlineGeometry
* @constructor
*
* @param {Object} options Object with the following properties:
* @param {Cartesian3} options.center The ellipse's center point in the fixed frame.
* @param {Number} options.semiMajorAxis The length of the ellipse's semi-major axis in meters.
* @param {Number} options.semiMinorAxis The length of the ellipse's semi-minor axis in meters.
* @param {Ellipsoid} [options.ellipsoid=Ellipsoid.WGS84] The ellipsoid the ellipse will be on.
* @param {Number} [options.height=0.0] The distance in meters between the ellipse and the ellipsoid surface.
* @param {Number} [options.extrudedHeight] The distance in meters between the ellipse's extruded face and the ellipsoid surface.
* @param {Number} [options.rotation=0.0] The angle from north (counter-clockwise) in radians.
* @param {Number} [options.granularity=0.02] The angular distance between points on the ellipse in radians.
* @param {Number} [options.numberOfVerticalLines=16] Number of lines to draw between the top and bottom surface of an extruded ellipse.
*
* @exception {DeveloperError} semiMajorAxis and semiMinorAxis must be greater than zero.
* @exception {DeveloperError} semiMajorAxis must be greater than or equal to the semiMinorAxis.
* @exception {DeveloperError} granularity must be greater than zero.
*
* @see EllipseOutlineGeometry.createGeometry
*
* @example
* var ellipse = new Cesium.EllipseOutlineGeometry({
* center : Cesium.Cartesian3.fromDegrees(-75.59777, 40.03883),
* semiMajorAxis : 500000.0,
* semiMinorAxis : 300000.0,
* rotation : Cesium.Math.toRadians(60.0)
* });
* var geometry = Cesium.EllipseOutlineGeometry.createGeometry(ellipse);
*/
function EllipseOutlineGeometry(options) {
options = defaultValue(options, defaultValue.EMPTY_OBJECT);
var center = options.center;
var ellipsoid = defaultValue(options.ellipsoid, Ellipsoid.WGS84);
var semiMajorAxis = options.semiMajorAxis;
var semiMinorAxis = options.semiMinorAxis;
var granularity = defaultValue(options.granularity, CesiumMath.RADIANS_PER_DEGREE);
//>>includeStart('debug', pragmas.debug);
if (!defined(center)) {
throw new DeveloperError('center is required.');
}
if (!defined(semiMajorAxis)) {
throw new DeveloperError('semiMajorAxis is required.');
}
if (!defined(semiMinorAxis)) {
throw new DeveloperError('semiMinorAxis is required.');
}
if (semiMajorAxis < semiMinorAxis) {
throw new DeveloperError('semiMajorAxis must be greater than or equal to the semiMinorAxis.');
}
if (granularity <= 0.0) {
throw new DeveloperError('granularity must be greater than zero.');
}
//>>includeEnd('debug');
var height = defaultValue(options.height, 0.0);
var extrudedHeight = defaultValue(options.extrudedHeight, height);
this._center = Cartesian3.clone(center);
this._semiMajorAxis = semiMajorAxis;
this._semiMinorAxis = semiMinorAxis;
this._ellipsoid = Ellipsoid.clone(ellipsoid);
this._rotation = defaultValue(options.rotation, 0.0);
this._height = Math.max(extrudedHeight, height);
this._granularity = granularity;
this._extrudedHeight = Math.min(extrudedHeight, height);
this._numberOfVerticalLines = Math.max(defaultValue(options.numberOfVerticalLines, 16), 0);
this._workerName = 'createEllipseOutlineGeometry';
}
/**
* The number of elements used to pack the object into an array.
* @type {Number}
*/
EllipseOutlineGeometry.packedLength = Cartesian3.packedLength + Ellipsoid.packedLength + 7;
/**
* Stores the provided instance into the provided array.
*
* @param {EllipseOutlineGeometry} value The value to pack.
* @param {Number[]} array The array to pack into.
* @param {Number} [startingIndex=0] The index into the array at which to start packing the elements.
*
* @returns {Number[]} The array that was packed into
*/
EllipseOutlineGeometry.pack = function(value, array, startingIndex) {
//>>includeStart('debug', pragmas.debug);
if (!defined(value)) {
throw new DeveloperError('value is required');
}
if (!defined(array)) {
throw new DeveloperError('array is required');
}
//>>includeEnd('debug');
startingIndex = defaultValue(startingIndex, 0);
Cartesian3.pack(value._center, array, startingIndex);
startingIndex += Cartesian3.packedLength;
Ellipsoid.pack(value._ellipsoid, array, startingIndex);
startingIndex += Ellipsoid.packedLength;
array[startingIndex++] = value._semiMajorAxis;
array[startingIndex++] = value._semiMinorAxis;
array[startingIndex++] = value._rotation;
array[startingIndex++] = value._height;
array[startingIndex++] = value._granularity;
array[startingIndex++] = value._extrudedHeight;
array[startingIndex] = value._numberOfVerticalLines;
return array;
};
var scratchCenter = new Cartesian3();
var scratchEllipsoid = new Ellipsoid();
var scratchOptions = {
center : scratchCenter,
ellipsoid : scratchEllipsoid,
semiMajorAxis : undefined,
semiMinorAxis : undefined,
rotation : undefined,
height : undefined,
granularity : undefined,
extrudedHeight : undefined,
numberOfVerticalLines : undefined
};
/**
* Retrieves an instance from a packed array.
*
* @param {Number[]} array The packed array.
* @param {Number} [startingIndex=0] The starting index of the element to be unpacked.
* @param {EllipseOutlineGeometry} [result] The object into which to store the result.
* @returns {EllipseOutlineGeometry} The modified result parameter or a new EllipseOutlineGeometry instance if one was not provided.
*/
EllipseOutlineGeometry.unpack = function(array, startingIndex, result) {
//>>includeStart('debug', pragmas.debug);
if (!defined(array)) {
throw new DeveloperError('array is required');
}
//>>includeEnd('debug');
startingIndex = defaultValue(startingIndex, 0);
var center = Cartesian3.unpack(array, startingIndex, scratchCenter);
startingIndex += Cartesian3.packedLength;
var ellipsoid = Ellipsoid.unpack(array, startingIndex, scratchEllipsoid);
startingIndex += Ellipsoid.packedLength;
var semiMajorAxis = array[startingIndex++];
var semiMinorAxis = array[startingIndex++];
var rotation = array[startingIndex++];
var height = array[startingIndex++];
var granularity = array[startingIndex++];
var extrudedHeight = array[startingIndex++];
var numberOfVerticalLines = array[startingIndex];
if (!defined(result)) {
scratchOptions.height = height;
scratchOptions.extrudedHeight = extrudedHeight;
scratchOptions.granularity = granularity;
scratchOptions.rotation = rotation;
scratchOptions.semiMajorAxis = semiMajorAxis;
scratchOptions.semiMinorAxis = semiMinorAxis;
scratchOptions.numberOfVerticalLines = numberOfVerticalLines;
return new EllipseOutlineGeometry(scratchOptions);
}
result._center = Cartesian3.clone(center, result._center);
result._ellipsoid = Ellipsoid.clone(ellipsoid, result._ellipsoid);
result._semiMajorAxis = semiMajorAxis;
result._semiMinorAxis = semiMinorAxis;
result._rotation = rotation;
result._height = height;
result._granularity = granularity;
result._extrudedHeight = extrudedHeight;
result._numberOfVerticalLines = numberOfVerticalLines;
return result;
};
/**
* Computes the geometric representation of an outline of an ellipse on an ellipsoid, including its vertices, indices, and a bounding sphere.
*
* @param {EllipseOutlineGeometry} ellipseGeometry A description of the ellipse.
* @returns {Geometry|undefined} The computed vertices and indices.
*/
EllipseOutlineGeometry.createGeometry = function(ellipseGeometry) {
if ((ellipseGeometry._semiMajorAxis <= 0.0) || (ellipseGeometry._semiMinorAxis <= 0.0)) {
return;
}
var height = ellipseGeometry._height;
var extrudedHeight = ellipseGeometry._extrudedHeight;
var extrude = !CesiumMath.equalsEpsilon(height, extrudedHeight, 0, CesiumMath.EPSILON2);
ellipseGeometry._center = ellipseGeometry._ellipsoid.scaleToGeodeticSurface(ellipseGeometry._center, ellipseGeometry._center);
var options = {
center : ellipseGeometry._center,
semiMajorAxis : ellipseGeometry._semiMajorAxis,
semiMinorAxis : ellipseGeometry._semiMinorAxis,
ellipsoid : ellipseGeometry._ellipsoid,
rotation : ellipseGeometry._rotation,
height : height,
granularity : ellipseGeometry._granularity,
numberOfVerticalLines : ellipseGeometry._numberOfVerticalLines
};
var geometry;
if (extrude) {
options.extrudedHeight = extrudedHeight;
geometry = computeExtrudedEllipse(options);
} else {
geometry = computeEllipse(options);
}
return new Geometry({
attributes : geometry.attributes,
indices : geometry.indices,
primitiveType : PrimitiveType.LINES,
boundingSphere : geometry.boundingSphere
});
};
return EllipseOutlineGeometry;
});