/*
* Copyright 2003-2006, 2009, 2017, United States Government, as represented by the Administrator of the
* National Aeronautics and Space Administration. All rights reserved.
*
* The NASAWorldWind/WebWorldWind platform is licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
/**
* @exports SurfaceEllipse
*/
define([
'../geom/Angle',
'../error/ArgumentError',
'../geom/Location',
'../util/Logger',
'../shapes/ShapeAttributes',
'../shapes/SurfaceShape',
'../util/WWMath'
],
function (Angle,
ArgumentError,
Location,
Logger,
ShapeAttributes,
SurfaceShape,
WWMath) {
"use strict";
/**
* Constructs a surface ellipse with a specified center and radii and an optional attributes bundle.
* @alias SurfaceEllipse
* @constructor
* @augments SurfaceShape
* @classdesc Represents an ellipse draped over the terrain surface.
* <p>
* SurfaceEllipse uses the following attributes from its associated shape attributes bundle:
* <ul>
* <li>Draw interior</li>
* <li>Draw outline</li>
* <li>Interior color</li>
* <li>Outline color</li>
* <li>Outline width</li>
* <li>Outline stipple factor</li>
* <li>Outline stipple pattern</li>
* </ul>
* @param {Location} center The ellipse's center location.
* @param {Number} majorRadius The ellipse's major radius in meters.
* @param {Number} minorRadius The ellipse's minor radius in meters.
* @param {Number} heading The heading of the major axis in degrees.
* @param {ShapeAttributes} attributes The attributes to apply to this shape. May be null, in which case
* attributes must be set directly before the shape is drawn.
* @throws {ArgumentError} If the specified center location is null or undefined or if either specified radii
* is negative.
*/
var SurfaceEllipse = function (center, majorRadius, minorRadius, heading, attributes) {
if (!center) {
throw new ArgumentError(
Logger.logMessage(Logger.LEVEL_SEVERE, "SurfaceEllipse", "constructor", "missingLocation"));
}
if (majorRadius < 0 || minorRadius < 0) {
throw new ArgumentError(
Logger.logMessage(Logger.LEVEL_SEVERE, "SurfaceEllipse", "constructor", "Radius is negative."));
}
SurfaceShape.call(this, attributes);
// All these are documented with their property accessors below.
this._center = center;
this._majorRadius = majorRadius;
this._minorRadius = minorRadius;
this._heading = heading;
this._intervals = SurfaceEllipse.DEFAULT_NUM_INTERVALS;
};
SurfaceEllipse.prototype = Object.create(SurfaceShape.prototype);
Object.defineProperties(SurfaceEllipse.prototype, {
/**
* This shape's center location.
* @memberof SurfaceEllipse.prototype
* @type {Location}
*/
center: {
get: function() {
return this._center;
},
set: function(value) {
this.stateKeyInvalid = true;
this.resetBoundaries();
this._center = value;
}
},
/**
* This shape's major radius, in meters.
* @memberof SurfaceEllipse.prototype
* @type {Number}
*/
majorRadius: {
get: function() {
return this._majorRadius;
},
set: function(value) {
this.stateKeyInvalid = true;
this.resetBoundaries();
this._majorRadius = value;
}
},
/**
* This shape's minor radius in meters.
* @memberof SurfaceEllipse.prototype
* @type {Number}
*/
minorRadius: {
get: function() {
return this._minorRadius;
},
set: function(value) {
this.stateKeyInvalid = true;
this.resetBoundaries();
this._minorRadius = value;
}
},
/**
* The heading of the major axis, specified as degrees clockwise from North.
* @type {Number}
* @memberof SurfaceEllipse.prototype
* @default 0
*/
heading: {
get: function() {
return this._heading;
},
set: function(value) {
this.stateKeyInvalid = true;
this.resetBoundaries();
this._heading = value;
}
},
/**
* The number of intervals to generate locations for.
* @type {Number}
* @memberof SurfaceEllipse.prototype
* @default SurfaceEllipse.DEFAULT_NUM_INTERVALS
*/
intervals: {
get: function() {
return this._intervals;
},
set: function(value) {
this.stateKeyInvalid = true;
this.resetBoundaries();
this._intervals = value;
}
}
});
// Internal use only. Intentionally not documented.
SurfaceEllipse.staticStateKey = function(shape) {
var shapeStateKey = SurfaceShape.staticStateKey(shape);
return shapeStateKey +
" ce " + shape.center.toString() +
" ma " + shape.majorRadius.toString() +
" mi " + shape.minorRadius.toString() +
" he " + shape.heading.toString() +
" in " + shape.intervals.toString();
};
// Internal use only. Intentionally not documented.
SurfaceEllipse.prototype.computeStateKey = function() {
return SurfaceEllipse.staticStateKey(this);
};
// Internal. Intentionally not documented.
SurfaceEllipse.prototype.computeBoundaries = function(dc) {
if (this.majorRadius == 0 && this.minorRadius == 0) {
return null;
}
var globe = dc.globe,
numLocations = 1 + Math.max(SurfaceEllipse.MIN_NUM_INTERVALS, this.intervals),
da = (2 * Math.PI) / (numLocations - 1),
globeRadius = globe.radiusAt(this.center.latitude, this.center.longitude);
this._boundaries = new Array(numLocations);
for (var i = 0; i < numLocations; i++) {
var angle = (i != numLocations - 1) ? i * da : 0,
xLength = this.majorRadius * Math.cos(angle),
yLength = this.minorRadius * Math.sin(angle),
distance = Math.sqrt(xLength * xLength + yLength * yLength);
// azimuth runs positive clockwise from north and through 360 degrees.
var azimuth = (Math.PI / 2.0) -
(Math.acos(xLength / distance) * WWMath.signum(yLength) - this.heading * Angle.DEGREES_TO_RADIANS);
this._boundaries[i] = Location.greatCircleLocation(this.center, azimuth * Angle.RADIANS_TO_DEGREES,
distance / globeRadius, new Location(0, 0));
}
};
// Internal use only. Intentionally not documented.
SurfaceEllipse.prototype.getReferencePosition = function () {
return this.center;
};
// Internal use only. Intentionally not documented.
SurfaceEllipse.prototype.moveTo = function (globe, position) {
this.center = position;
};
/**
* The minimum number of intervals the ellipse generates.
* @type {Number}
*/
SurfaceEllipse.MIN_NUM_INTERVALS = 8;
/**
* The default number of intervals the ellipse generates.
* @type {Number}
*/
SurfaceEllipse.DEFAULT_NUM_INTERVALS = 64;
return SurfaceEllipse;
});