cesium
Version:
CesiumJS is a JavaScript library for creating 3D globes and 2D maps in a web browser without a plugin.
349 lines (311 loc) • 12.8 kB
JavaScript
define([
'./AxisAlignedBoundingBox',
'./Cartesian2',
'./Cartesian3',
'./Cartesian4',
'./defaultValue',
'./defined',
'./defineProperties',
'./DeveloperError',
'./Ellipsoid',
'./IntersectionTests',
'./Matrix4',
'./Plane',
'./Ray',
'./Transforms'
], function(
AxisAlignedBoundingBox,
Cartesian2,
Cartesian3,
Cartesian4,
defaultValue,
defined,
defineProperties,
DeveloperError,
Ellipsoid,
IntersectionTests,
Matrix4,
Plane,
Ray,
Transforms) {
'use strict';
var scratchCart4 = new Cartesian4();
/**
* A plane tangent to the provided ellipsoid at the provided origin.
* If origin is not on the surface of the ellipsoid, it's surface projection will be used.
* If origin is at the center of the ellipsoid, an exception will be thrown.
* @alias EllipsoidTangentPlane
* @constructor
*
* @param {Cartesian3} origin The point on the surface of the ellipsoid where the tangent plane touches.
* @param {Ellipsoid} [ellipsoid=Ellipsoid.WGS84] The ellipsoid to use.
*
* @exception {DeveloperError} origin must not be at the center of the ellipsoid.
*/
function EllipsoidTangentPlane(origin, ellipsoid) {
//>>includeStart('debug', pragmas.debug);
if (!defined(origin)) {
throw new DeveloperError('origin is required.');
}
//>>includeEnd('debug');
ellipsoid = defaultValue(ellipsoid, Ellipsoid.WGS84);
origin = ellipsoid.scaleToGeodeticSurface(origin);
//>>includeStart('debug', pragmas.debug);
if (!defined(origin)) {
throw new DeveloperError('origin must not be at the center of the ellipsoid.');
}
//>>includeEnd('debug');
var eastNorthUp = Transforms.eastNorthUpToFixedFrame(origin, ellipsoid);
this._ellipsoid = ellipsoid;
this._origin = origin;
this._xAxis = Cartesian3.fromCartesian4(Matrix4.getColumn(eastNorthUp, 0, scratchCart4));
this._yAxis = Cartesian3.fromCartesian4(Matrix4.getColumn(eastNorthUp, 1, scratchCart4));
var normal = Cartesian3.fromCartesian4(Matrix4.getColumn(eastNorthUp, 2, scratchCart4));
this._plane = Plane.fromPointNormal(origin, normal);
}
defineProperties(EllipsoidTangentPlane.prototype, {
/**
* Gets the ellipsoid.
* @memberof EllipsoidTangentPlane.prototype
* @type {Ellipsoid}
*/
ellipsoid : {
get : function() {
return this._ellipsoid;
}
},
/**
* Gets the origin.
* @memberof EllipsoidTangentPlane.prototype
* @type {Cartesian3}
*/
origin : {
get : function() {
return this._origin;
}
},
/**
* Gets the plane which is tangent to the ellipsoid.
* @memberof EllipsoidTangentPlane.prototype
* @readonly
* @type {Plane}
*/
plane : {
get : function() {
return this._plane;
}
},
/**
* Gets the local X-axis (east) of the tangent plane.
* @memberof EllipsoidTangentPlane.prototype
* @readonly
* @type {Cartesian3}
*/
xAxis : {
get : function() {
return this._xAxis;
}
},
/**
* Gets the local Y-axis (north) of the tangent plane.
* @memberof EllipsoidTangentPlane.prototype
* @readonly
* @type {Cartesian3}
*/
yAxis : {
get : function() {
return this._yAxis;
}
},
/**
* Gets the local Z-axis (up) of the tangent plane.
* @member EllipsoidTangentPlane.prototype
* @readonly
* @type {Cartesian3}
*/
zAxis : {
get : function() {
return this._plane.normal;
}
}
});
var tmp = new AxisAlignedBoundingBox();
/**
* Creates a new instance from the provided ellipsoid and the center
* point of the provided Cartesians.
*
* @param {Ellipsoid} ellipsoid The ellipsoid to use.
* @param {Cartesian3} cartesians The list of positions surrounding the center point.
*/
EllipsoidTangentPlane.fromPoints = function(cartesians, ellipsoid) {
//>>includeStart('debug', pragmas.debug);
if (!defined(cartesians)) {
throw new DeveloperError('cartesians is required.');
}
//>>includeEnd('debug');
var box = AxisAlignedBoundingBox.fromPoints(cartesians, tmp);
return new EllipsoidTangentPlane(box.center, ellipsoid);
};
var scratchProjectPointOntoPlaneRay = new Ray();
var scratchProjectPointOntoPlaneCartesian3 = new Cartesian3();
/**
* Computes the projection of the provided 3D position onto the 2D plane, radially outward from the {@link EllipsoidTangentPlane.ellipsoid} coordinate system origin.
*
* @param {Cartesian3} cartesian The point to project.
* @param {Cartesian2} [result] The object onto which to store the result.
* @returns {Cartesian2} The modified result parameter or a new Cartesian2 instance if none was provided. Undefined if there is no intersection point
*/
EllipsoidTangentPlane.prototype.projectPointOntoPlane = function(cartesian, result) {
//>>includeStart('debug', pragmas.debug);
if (!defined(cartesian)) {
throw new DeveloperError('cartesian is required.');
}
//>>includeEnd('debug');
var ray = scratchProjectPointOntoPlaneRay;
ray.origin = cartesian;
Cartesian3.normalize(cartesian, ray.direction);
var intersectionPoint = IntersectionTests.rayPlane(ray, this._plane, scratchProjectPointOntoPlaneCartesian3);
if (!defined(intersectionPoint)) {
Cartesian3.negate(ray.direction, ray.direction);
intersectionPoint = IntersectionTests.rayPlane(ray, this._plane, scratchProjectPointOntoPlaneCartesian3);
}
if (defined(intersectionPoint)) {
var v = Cartesian3.subtract(intersectionPoint, this._origin, intersectionPoint);
var x = Cartesian3.dot(this._xAxis, v);
var y = Cartesian3.dot(this._yAxis, v);
if (!defined(result)) {
return new Cartesian2(x, y);
}
result.x = x;
result.y = y;
return result;
}
return undefined;
};
/**
* Computes the projection of the provided 3D positions onto the 2D plane (where possible), radially outward from the global origin.
* The resulting array may be shorter than the input array - if a single projection is impossible it will not be included.
*
* @see EllipsoidTangentPlane.projectPointOntoPlane
*
* @param {Cartesian3[]} cartesians The array of points to project.
* @param {Cartesian2[]} [result] The array of Cartesian2 instances onto which to store results.
* @returns {Cartesian2[]} The modified result parameter or a new array of Cartesian2 instances if none was provided.
*/
EllipsoidTangentPlane.prototype.projectPointsOntoPlane = function(cartesians, result) {
//>>includeStart('debug', pragmas.debug);
if (!defined(cartesians)) {
throw new DeveloperError('cartesians is required.');
}
//>>includeEnd('debug');
if (!defined(result)) {
result = [];
}
var count = 0;
var length = cartesians.length;
for ( var i = 0; i < length; i++) {
var p = this.projectPointOntoPlane(cartesians[i], result[count]);
if (defined(p)) {
result[count] = p;
count++;
}
}
result.length = count;
return result;
};
/**
* Computes the projection of the provided 3D position onto the 2D plane, along the plane normal.
*
* @param {Cartesian3} cartesian The point to project.
* @param {Cartesian2} [result] The object onto which to store the result.
* @returns {Cartesian2} The modified result parameter or a new Cartesian2 instance if none was provided.
*/
EllipsoidTangentPlane.prototype.projectPointToNearestOnPlane = function(cartesian, result) {
//>>includeStart('debug', pragmas.debug);
if (!defined(cartesian)) {
throw new DeveloperError('cartesian is required.');
}
//>>includeEnd('debug');
if (!defined(result)) {
result = new Cartesian2();
}
var ray = scratchProjectPointOntoPlaneRay;
ray.origin = cartesian;
Cartesian3.clone(this._plane.normal, ray.direction);
var intersectionPoint = IntersectionTests.rayPlane(ray, this._plane, scratchProjectPointOntoPlaneCartesian3);
if (!defined(intersectionPoint)) {
Cartesian3.negate(ray.direction, ray.direction);
intersectionPoint = IntersectionTests.rayPlane(ray, this._plane, scratchProjectPointOntoPlaneCartesian3);
}
var v = Cartesian3.subtract(intersectionPoint, this._origin, intersectionPoint);
var x = Cartesian3.dot(this._xAxis, v);
var y = Cartesian3.dot(this._yAxis, v);
result.x = x;
result.y = y;
return result;
};
/**
* Computes the projection of the provided 3D positions onto the 2D plane, along the plane normal.
*
* @see EllipsoidTangentPlane.projectPointToNearestOnPlane
*
* @param {Cartesian3[]} cartesians The array of points to project.
* @param {Cartesian2[]} [result] The array of Cartesian2 instances onto which to store results.
* @returns {Cartesian2[]} The modified result parameter or a new array of Cartesian2 instances if none was provided. This will have the same length as <code>cartesians</code>.
*/
EllipsoidTangentPlane.prototype.projectPointsToNearestOnPlane = function(cartesians, result) {
//>>includeStart('debug', pragmas.debug);
if (!defined(cartesians)) {
throw new DeveloperError('cartesians is required.');
}
//>>includeEnd('debug');
if (!defined(result)) {
result = [];
}
var length = cartesians.length;
result.length = length;
for (var i = 0; i < length; i++) {
result[i] = this.projectPointToNearestOnPlane(cartesians[i], result[i]);
}
return result;
};
var projectPointsOntoEllipsoidScratch = new Cartesian3();
/**
* Computes the projection of the provided 2D positions onto the 3D ellipsoid.
*
* @param {Cartesian2[]} cartesians The array of points to project.
* @param {Cartesian3[]} [result] The array of Cartesian3 instances onto which to store results.
* @returns {Cartesian3[]} The modified result parameter or a new array of Cartesian3 instances if none was provided.
*/
EllipsoidTangentPlane.prototype.projectPointsOntoEllipsoid = function(cartesians, result) {
//>>includeStart('debug', pragmas.debug);
if (!defined(cartesians)) {
throw new DeveloperError('cartesians is required.');
}
//>>includeEnd('debug');
var length = cartesians.length;
if (!defined(result)) {
result = new Array(length);
} else {
result.length = length;
}
var ellipsoid = this._ellipsoid;
var origin = this._origin;
var xAxis = this._xAxis;
var yAxis = this._yAxis;
var tmp = projectPointsOntoEllipsoidScratch;
for ( var i = 0; i < length; ++i) {
var position = cartesians[i];
Cartesian3.multiplyByScalar(xAxis, position.x, tmp);
if (!defined(result[i])) {
result[i] = new Cartesian3();
}
var point = Cartesian3.add(origin, tmp, result[i]);
Cartesian3.multiplyByScalar(yAxis, position.y, tmp);
Cartesian3.add(point, tmp, point);
ellipsoid.scaleToGeocentricSurface(point, point);
}
return result;
};
return EllipsoidTangentPlane;
});