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
import BoundingSphere from '../Core/BoundingSphere.js';
import Cartesian3 from '../Core/Cartesian3.js';
import Cartographic from '../Core/Cartographic.js';
import Check from '../Core/Check.js';
import ColorGeometryInstanceAttribute from '../Core/ColorGeometryInstanceAttribute.js';
import defaultValue from '../Core/defaultValue.js';
import Ellipsoid from '../Core/Ellipsoid.js';
import GeometryInstance from '../Core/GeometryInstance.js';
import IntersectionTests from '../Core/IntersectionTests.js';
import Matrix4 from '../Core/Matrix4.js';
import OrientedBoundingBox from '../Core/OrientedBoundingBox.js';
import Plane from '../Core/Plane.js';
import Ray from '../Core/Ray.js';
import Rectangle from '../Core/Rectangle.js';
import RectangleOutlineGeometry from '../Core/RectangleOutlineGeometry.js';
import PerInstanceColorAppearance from './PerInstanceColorAppearance.js';
import Primitive from './Primitive.js';
import SceneMode from './SceneMode.js';
/**
* A tile bounding volume specified as a longitude/latitude/height region.
* @alias TileBoundingRegion
* @constructor
*
* @param {Object} options Object with the following properties:
* @param {Rectangle} options.rectangle The rectangle specifying the longitude and latitude range of the region.
* @param {Number} [options.minimumHeight=0.0] The minimum height of the region.
* @param {Number} [options.maximumHeight=0.0] The maximum height of the region.
* @param {Ellipsoid} [options.ellipsoid=Cesium.Ellipsoid.WGS84] The ellipsoid.
* @param {Boolean} [options.computeBoundingVolumes=true] True to compute the {@link TileBoundingRegion#boundingVolume} and
* {@link TileBoundingVolume#boundingSphere}. If false, these properties will be undefined.
*
* @private
*/
function TileBoundingRegion(options) {
//>>includeStart('debug', pragmas.debug);
Check.typeOf.object('options', options);
Check.typeOf.object('options.rectangle', options.rectangle);
//>>includeEnd('debug');
this.rectangle = Rectangle.clone(options.rectangle);
this.minimumHeight = defaultValue(options.minimumHeight, 0.0);
this.maximumHeight = defaultValue(options.maximumHeight, 0.0);
/**
* The world coordinates of the southwest corner of the tile's rectangle.
*
* @type {Cartesian3}
* @default Cartesian3()
*/
this.southwestCornerCartesian = new Cartesian3();
/**
* The world coordinates of the northeast corner of the tile's rectangle.
*
* @type {Cartesian3}
* @default Cartesian3()
*/
this.northeastCornerCartesian = new Cartesian3();
/**
* A normal that, along with southwestCornerCartesian, defines a plane at the western edge of
* the tile. Any position above (in the direction of the normal) this plane is outside the tile.
*
* @type {Cartesian3}
* @default Cartesian3()
*/
this.westNormal = new Cartesian3();
/**
* A normal that, along with southwestCornerCartesian, defines a plane at the southern edge of
* the tile. Any position above (in the direction of the normal) this plane is outside the tile.
* Because points of constant latitude do not necessary lie in a plane, positions below this
* plane are not necessarily inside the tile, but they are close.
*
* @type {Cartesian3}
* @default Cartesian3()
*/
this.southNormal = new Cartesian3();
/**
* A normal that, along with northeastCornerCartesian, defines a plane at the eastern edge of
* the tile. Any position above (in the direction of the normal) this plane is outside the tile.
*
* @type {Cartesian3}
* @default Cartesian3()
*/
this.eastNormal = new Cartesian3();
/**
* A normal that, along with northeastCornerCartesian, defines a plane at the eastern edge of
* the tile. Any position above (in the direction of the normal) this plane is outside the tile.
* Because points of constant latitude do not necessary lie in a plane, positions below this
* plane are not necessarily inside the tile, but they are close.
*
* @type {Cartesian3}
* @default Cartesian3()
*/
this.northNormal = new Cartesian3();
var ellipsoid = defaultValue(options.ellipsoid, Ellipsoid.WGS84);
computeBox(this, options.rectangle, ellipsoid);
if (defaultValue(options.computeBoundingVolumes, true)) {
// An oriented bounding box that encloses this tile's region. This is used to calculate tile visibility.
this._orientedBoundingBox = OrientedBoundingBox.fromRectangle(this.rectangle, this.minimumHeight, this.maximumHeight, ellipsoid);
this._boundingSphere = BoundingSphere.fromOrientedBoundingBox(this._orientedBoundingBox);
}
}
Object.defineProperties(TileBoundingRegion.prototype, {
/**
* The underlying bounding volume
*
* @memberof TileBoundingRegion.prototype
*
* @type {Object}
* @readonly
*/
boundingVolume : {
get : function() {
return this._orientedBoundingBox;
}
},
/**
* The underlying bounding sphere
*
* @memberof TileBoundingRegion.prototype
*
* @type {BoundingSphere}
* @readonly
*/
boundingSphere : {
get : function() {
return this._boundingSphere;
}
}
});
var cartesian3Scratch = new Cartesian3();
var cartesian3Scratch2 = new Cartesian3();
var cartesian3Scratch3 = new Cartesian3();
var eastWestNormalScratch = new Cartesian3();
var westernMidpointScratch = new Cartesian3();
var easternMidpointScratch = new Cartesian3();
var cartographicScratch = new Cartographic();
var planeScratch = new Plane(Cartesian3.UNIT_X, 0.0);
var rayScratch = new Ray();
function computeBox(tileBB, rectangle, ellipsoid) {
ellipsoid.cartographicToCartesian(Rectangle.southwest(rectangle), tileBB.southwestCornerCartesian);
ellipsoid.cartographicToCartesian(Rectangle.northeast(rectangle), tileBB.northeastCornerCartesian);
// The middle latitude on the western edge.
cartographicScratch.longitude = rectangle.west;
cartographicScratch.latitude = (rectangle.south + rectangle.north) * 0.5;
cartographicScratch.height = 0.0;
var westernMidpointCartesian = ellipsoid.cartographicToCartesian(cartographicScratch, westernMidpointScratch);
// Compute the normal of the plane on the western edge of the tile.
var westNormal = Cartesian3.cross(westernMidpointCartesian, Cartesian3.UNIT_Z, cartesian3Scratch);
Cartesian3.normalize(westNormal, tileBB.westNormal);
// The middle latitude on the eastern edge.
cartographicScratch.longitude = rectangle.east;
var easternMidpointCartesian = ellipsoid.cartographicToCartesian(cartographicScratch, easternMidpointScratch);
// Compute the normal of the plane on the eastern edge of the tile.
var eastNormal = Cartesian3.cross(Cartesian3.UNIT_Z, easternMidpointCartesian, cartesian3Scratch);
Cartesian3.normalize(eastNormal, tileBB.eastNormal);
// Compute the normal of the plane bounding the southern edge of the tile.
var westVector = Cartesian3.subtract(westernMidpointCartesian, easternMidpointCartesian, cartesian3Scratch);
var eastWestNormal = Cartesian3.normalize(westVector, eastWestNormalScratch);
var south = rectangle.south;
var southSurfaceNormal;
if (south > 0.0) {
// Compute a plane that doesn't cut through the tile.
cartographicScratch.longitude = (rectangle.west + rectangle.east) * 0.5;
cartographicScratch.latitude = south;
var southCenterCartesian = ellipsoid.cartographicToCartesian(cartographicScratch, rayScratch.origin);
Cartesian3.clone(eastWestNormal, rayScratch.direction);
var westPlane = Plane.fromPointNormal(tileBB.southwestCornerCartesian, tileBB.westNormal, planeScratch);
// Find a point that is on the west and the south planes
IntersectionTests.rayPlane(rayScratch, westPlane, tileBB.southwestCornerCartesian);
southSurfaceNormal = ellipsoid.geodeticSurfaceNormal(southCenterCartesian, cartesian3Scratch2);
} else {
southSurfaceNormal = ellipsoid.geodeticSurfaceNormalCartographic(Rectangle.southeast(rectangle), cartesian3Scratch2);
}
var southNormal = Cartesian3.cross(southSurfaceNormal, westVector, cartesian3Scratch3);
Cartesian3.normalize(southNormal, tileBB.southNormal);
// Compute the normal of the plane bounding the northern edge of the tile.
var north = rectangle.north;
var northSurfaceNormal;
if (north < 0.0) {
// Compute a plane that doesn't cut through the tile.
cartographicScratch.longitude = (rectangle.west + rectangle.east) * 0.5;
cartographicScratch.latitude = north;
var northCenterCartesian = ellipsoid.cartographicToCartesian(cartographicScratch, rayScratch.origin);
Cartesian3.negate(eastWestNormal, rayScratch.direction);
var eastPlane = Plane.fromPointNormal(tileBB.northeastCornerCartesian, tileBB.eastNormal, planeScratch);
// Find a point that is on the east and the north planes
IntersectionTests.rayPlane(rayScratch, eastPlane, tileBB.northeastCornerCartesian);
northSurfaceNormal = ellipsoid.geodeticSurfaceNormal(northCenterCartesian, cartesian3Scratch2);
} else {
northSurfaceNormal = ellipsoid.geodeticSurfaceNormalCartographic(Rectangle.northwest(rectangle), cartesian3Scratch2);
}
var northNormal = Cartesian3.cross(westVector, northSurfaceNormal, cartesian3Scratch3);
Cartesian3.normalize(northNormal, tileBB.northNormal);
}
var southwestCornerScratch = new Cartesian3();
var northeastCornerScratch = new Cartesian3();
var negativeUnitY = new Cartesian3(0.0, -1.0, 0.0);
var negativeUnitZ = new Cartesian3(0.0, 0.0, -1.0);
var vectorScratch = new Cartesian3();
/**
* Gets the distance from the camera to the closest point on the tile. This is used for level of detail selection.
*
* @param {FrameState} frameState The state information of the current rendering frame.
* @returns {Number} The distance from the camera to the closest point on the tile, in meters.
*/
TileBoundingRegion.prototype.distanceToCamera = function(frameState) {
//>>includeStart('debug', pragmas.debug);
Check.defined('frameState', frameState);
//>>includeEnd('debug');
var camera = frameState.camera;
var cameraCartesianPosition = camera.positionWC;
var cameraCartographicPosition = camera.positionCartographic;
var result = 0.0;
if (!Rectangle.contains(this.rectangle, cameraCartographicPosition)) {
var southwestCornerCartesian = this.southwestCornerCartesian;
var northeastCornerCartesian = this.northeastCornerCartesian;
var westNormal = this.westNormal;
var southNormal = this.southNormal;
var eastNormal = this.eastNormal;
var northNormal = this.northNormal;
if (frameState.mode !== SceneMode.SCENE3D) {
southwestCornerCartesian = frameState.mapProjection.project(Rectangle.southwest(this.rectangle), southwestCornerScratch);
southwestCornerCartesian.z = southwestCornerCartesian.y;
southwestCornerCartesian.y = southwestCornerCartesian.x;
southwestCornerCartesian.x = 0.0;
northeastCornerCartesian = frameState.mapProjection.project(Rectangle.northeast(this.rectangle), northeastCornerScratch);
northeastCornerCartesian.z = northeastCornerCartesian.y;
northeastCornerCartesian.y = northeastCornerCartesian.x;
northeastCornerCartesian.x = 0.0;
westNormal = negativeUnitY;
eastNormal = Cartesian3.UNIT_Y;
southNormal = negativeUnitZ;
northNormal = Cartesian3.UNIT_Z;
}
var vectorFromSouthwestCorner = Cartesian3.subtract(cameraCartesianPosition, southwestCornerCartesian, vectorScratch);
var distanceToWestPlane = Cartesian3.dot(vectorFromSouthwestCorner, westNormal);
var distanceToSouthPlane = Cartesian3.dot(vectorFromSouthwestCorner, southNormal);
var vectorFromNortheastCorner = Cartesian3.subtract(cameraCartesianPosition, northeastCornerCartesian, vectorScratch);
var distanceToEastPlane = Cartesian3.dot(vectorFromNortheastCorner, eastNormal);
var distanceToNorthPlane = Cartesian3.dot(vectorFromNortheastCorner, northNormal);
if (distanceToWestPlane > 0.0) {
result += distanceToWestPlane * distanceToWestPlane;
} else if (distanceToEastPlane > 0.0) {
result += distanceToEastPlane * distanceToEastPlane;
}
if (distanceToSouthPlane > 0.0) {
result += distanceToSouthPlane * distanceToSouthPlane;
} else if (distanceToNorthPlane > 0.0) {
result += distanceToNorthPlane * distanceToNorthPlane;
}
}
var cameraHeight;
var minimumHeight;
var maximumHeight;
if (frameState.mode === SceneMode.SCENE3D) {
cameraHeight = cameraCartographicPosition.height;
minimumHeight = this.minimumHeight;
maximumHeight = this.maximumHeight;
} else {
cameraHeight = cameraCartesianPosition.x;
minimumHeight = 0.0;
maximumHeight = 0.0;
}
if (cameraHeight > maximumHeight) {
var distanceAboveTop = cameraHeight - maximumHeight;
result += distanceAboveTop * distanceAboveTop;
} else if (cameraHeight < minimumHeight) {
var distanceBelowBottom = minimumHeight - cameraHeight;
result += distanceBelowBottom * distanceBelowBottom;
}
return Math.sqrt(result);
};
/**
* Determines which side of a plane this box is located.
*
* @param {Plane} plane The plane to test against.
* @returns {Intersect} {@link Intersect.INSIDE} if the entire box is on the side of the plane
* the normal is pointing, {@link Intersect.OUTSIDE} if the entire box is
* on the opposite side, and {@link Intersect.INTERSECTING} if the box
* intersects the plane.
*/
TileBoundingRegion.prototype.intersectPlane = function(plane) {
//>>includeStart('debug', pragmas.debug);
Check.defined('plane', plane);
//>>includeEnd('debug');
return this._orientedBoundingBox.intersectPlane(plane);
};
/**
* Creates a debug primitive that shows the outline of the tile bounding region.
*
* @param {Color} color The desired color of the primitive's mesh
* @return {Primitive}
*
* @private
*/
TileBoundingRegion.prototype.createDebugVolume = function(color) {
//>>includeStart('debug', pragmas.debug);
Check.defined('color', color);
//>>includeEnd('debug');
var modelMatrix = new Matrix4.clone(Matrix4.IDENTITY);
var geometry = new RectangleOutlineGeometry({
rectangle : this.rectangle,
height : this.minimumHeight,
extrudedHeight: this.maximumHeight
});
var instance = new GeometryInstance({
geometry : geometry,
id : 'outline',
modelMatrix : modelMatrix,
attributes : {
color : ColorGeometryInstanceAttribute.fromColor(color)
}
});
return new Primitive({
geometryInstances : instance,
appearance : new PerInstanceColorAppearance({
translucent : false,
flat : true
}),
asynchronous : false
});
};
export default TileBoundingRegion;