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 Cartesian3 from '../Core/Cartesian3.js';
import Check from '../Core/Check.js';
import defaultValue from '../Core/defaultValue.js';
import defined from '../Core/defined.js';
import Ellipsoid from '../Core/Ellipsoid.js';
import HeadingPitchRange from '../Core/HeadingPitchRange.js';
import JulianDate from '../Core/JulianDate.js';
import CesiumMath from '../Core/Math.js';
import Matrix3 from '../Core/Matrix3.js';
import Matrix4 from '../Core/Matrix4.js';
import Transforms from '../Core/Transforms.js';
import SceneMode from '../Scene/SceneMode.js';
var updateTransformMatrix3Scratch1 = new Matrix3();
var updateTransformMatrix3Scratch2 = new Matrix3();
var updateTransformMatrix3Scratch3 = new Matrix3();
var updateTransformMatrix4Scratch = new Matrix4();
var updateTransformCartesian3Scratch1 = new Cartesian3();
var updateTransformCartesian3Scratch2 = new Cartesian3();
var updateTransformCartesian3Scratch3 = new Cartesian3();
var updateTransformCartesian3Scratch4 = new Cartesian3();
var updateTransformCartesian3Scratch5 = new Cartesian3();
var updateTransformCartesian3Scratch6 = new Cartesian3();
var deltaTime = new JulianDate();
var northUpAxisFactor = 1.25; // times ellipsoid's maximum radius
function updateTransform(that, camera, updateLookAt, saveCamera, positionProperty, time, ellipsoid) {
var mode = that.scene.mode;
var cartesian = positionProperty.getValue(time, that._lastCartesian);
if (defined(cartesian)) {
var hasBasis = false;
var invertVelocity = false;
var xBasis;
var yBasis;
var zBasis;
if (mode === SceneMode.SCENE3D) {
// The time delta was determined based on how fast satellites move compared to vehicles near the surface.
// Slower moving vehicles will most likely default to east-north-up, while faster ones will be VVLH.
JulianDate.addSeconds(time, 0.001, deltaTime);
var deltaCartesian = positionProperty.getValue(deltaTime, updateTransformCartesian3Scratch1);
// If no valid position at (time + 0.001), sample at (time - 0.001) and invert the vector
if (!defined(deltaCartesian)) {
JulianDate.addSeconds(time, -0.001, deltaTime);
deltaCartesian = positionProperty.getValue(deltaTime, updateTransformCartesian3Scratch1);
invertVelocity = true;
}
if (defined(deltaCartesian)) {
var toInertial = Transforms.computeFixedToIcrfMatrix(time, updateTransformMatrix3Scratch1);
var toInertialDelta = Transforms.computeFixedToIcrfMatrix(deltaTime, updateTransformMatrix3Scratch2);
var toFixed;
if (!defined(toInertial) || !defined(toInertialDelta)) {
toFixed = Transforms.computeTemeToPseudoFixedMatrix(time, updateTransformMatrix3Scratch3);
toInertial = Matrix3.transpose(toFixed, updateTransformMatrix3Scratch1);
toInertialDelta = Transforms.computeTemeToPseudoFixedMatrix(deltaTime, updateTransformMatrix3Scratch2);
Matrix3.transpose(toInertialDelta, toInertialDelta);
} else {
toFixed = Matrix3.transpose(toInertial, updateTransformMatrix3Scratch3);
}
var inertialCartesian = Matrix3.multiplyByVector(toInertial, cartesian, updateTransformCartesian3Scratch5);
var inertialDeltaCartesian = Matrix3.multiplyByVector(toInertialDelta, deltaCartesian, updateTransformCartesian3Scratch6);
Cartesian3.subtract(inertialCartesian, inertialDeltaCartesian, updateTransformCartesian3Scratch4);
var inertialVelocity = Cartesian3.magnitude(updateTransformCartesian3Scratch4) * 1000.0; // meters/sec
var mu = CesiumMath.GRAVITATIONALPARAMETER; // m^3 / sec^2
var semiMajorAxis = -mu / (inertialVelocity * inertialVelocity - (2 * mu / Cartesian3.magnitude(inertialCartesian)));
if (semiMajorAxis < 0 || semiMajorAxis > northUpAxisFactor * ellipsoid.maximumRadius) {
// North-up viewing from deep space.
// X along the nadir
xBasis = updateTransformCartesian3Scratch2;
Cartesian3.normalize(cartesian, xBasis);
Cartesian3.negate(xBasis, xBasis);
// Z is North
zBasis = Cartesian3.clone(Cartesian3.UNIT_Z, updateTransformCartesian3Scratch3);
// Y is along the cross of z and x (right handed basis / in the direction of motion)
yBasis = Cartesian3.cross(zBasis, xBasis, updateTransformCartesian3Scratch1);
if (Cartesian3.magnitude(yBasis) > CesiumMath.EPSILON7) {
Cartesian3.normalize(xBasis, xBasis);
Cartesian3.normalize(yBasis, yBasis);
zBasis = Cartesian3.cross(xBasis, yBasis, updateTransformCartesian3Scratch3);
Cartesian3.normalize(zBasis, zBasis);
hasBasis = true;
}
} else if (!Cartesian3.equalsEpsilon(cartesian, deltaCartesian, CesiumMath.EPSILON7)) {
// Approximation of VVLH (Vehicle Velocity Local Horizontal) with the Z-axis flipped.
// Z along the position
zBasis = updateTransformCartesian3Scratch2;
Cartesian3.normalize(inertialCartesian, zBasis);
Cartesian3.normalize(inertialDeltaCartesian, inertialDeltaCartesian);
// Y is along the angular momentum vector (e.g. "orbit normal")
yBasis = Cartesian3.cross(zBasis, inertialDeltaCartesian, updateTransformCartesian3Scratch3);
if(invertVelocity) {
yBasis = Cartesian3.multiplyByScalar(yBasis, -1, yBasis);
}
if (!Cartesian3.equalsEpsilon(yBasis, Cartesian3.ZERO, CesiumMath.EPSILON7)) {
// X is along the cross of y and z (right handed basis / in the direction of motion)
xBasis = Cartesian3.cross(yBasis, zBasis, updateTransformCartesian3Scratch1);
Matrix3.multiplyByVector(toFixed, xBasis, xBasis);
Matrix3.multiplyByVector(toFixed, yBasis, yBasis);
Matrix3.multiplyByVector(toFixed, zBasis, zBasis);
Cartesian3.normalize(xBasis, xBasis);
Cartesian3.normalize(yBasis, yBasis);
Cartesian3.normalize(zBasis, zBasis);
hasBasis = true;
}
}
}
}
if (defined(that.boundingSphere)) {
cartesian = that.boundingSphere.center;
}
var position;
var direction;
var up;
if (saveCamera) {
position = Cartesian3.clone(camera.position, updateTransformCartesian3Scratch4);
direction = Cartesian3.clone(camera.direction, updateTransformCartesian3Scratch5);
up = Cartesian3.clone(camera.up, updateTransformCartesian3Scratch6);
}
var transform = updateTransformMatrix4Scratch;
if (hasBasis) {
transform[0] = xBasis.x;
transform[1] = xBasis.y;
transform[2] = xBasis.z;
transform[3] = 0.0;
transform[4] = yBasis.x;
transform[5] = yBasis.y;
transform[6] = yBasis.z;
transform[7] = 0.0;
transform[8] = zBasis.x;
transform[9] = zBasis.y;
transform[10] = zBasis.z;
transform[11] = 0.0;
transform[12] = cartesian.x;
transform[13] = cartesian.y;
transform[14] = cartesian.z;
transform[15] = 0.0;
} else {
// Stationary or slow-moving, low-altitude objects use East-North-Up.
Transforms.eastNorthUpToFixedFrame(cartesian, ellipsoid, transform);
}
camera._setTransform(transform);
if (saveCamera) {
Cartesian3.clone(position, camera.position);
Cartesian3.clone(direction, camera.direction);
Cartesian3.clone(up, camera.up);
Cartesian3.cross(direction, up, camera.right);
}
}
if (updateLookAt) {
var offset = (mode === SceneMode.SCENE2D || Cartesian3.equals(that._offset3D, Cartesian3.ZERO)) ? undefined : that._offset3D;
camera.lookAtTransform(camera.transform, offset);
}
}
/**
* A utility object for tracking an entity with the camera.
* @alias EntityView
* @constructor
*
* @param {Entity} entity The entity to track with the camera.
* @param {Scene} scene The scene to use.
* @param {Ellipsoid} [ellipsoid=Ellipsoid.WGS84] The ellipsoid to use for orienting the camera.
*/
function EntityView(entity, scene, ellipsoid) {
//>>includeStart('debug', pragmas.debug);
Check.defined('entity', entity);
Check.defined('scene', scene);
//>>includeEnd('debug');
/**
* The entity to track with the camera.
* @type {Entity}
*/
this.entity = entity;
/**
* The scene in which to track the object.
* @type {Scene}
*/
this.scene = scene;
/**
* The ellipsoid to use for orienting the camera.
* @type {Ellipsoid}
*/
this.ellipsoid = defaultValue(ellipsoid, Ellipsoid.WGS84);
/**
* The bounding sphere of the object.
* @type {BoundingSphere}
*/
this.boundingSphere = undefined;
// Shadow copies of the objects so we can detect changes.
this._lastEntity = undefined;
this._mode = undefined;
this._lastCartesian = new Cartesian3();
this._defaultOffset3D = undefined;
this._offset3D = new Cartesian3();
}
// STATIC properties defined here, not per-instance.
Object.defineProperties(EntityView, {
/**
* Gets or sets a camera offset that will be used to
* initialize subsequent EntityViews.
* @memberof EntityView
* @type {Cartesian3}
*/
defaultOffset3D : {
get : function() {
return this._defaultOffset3D;
},
set : function(vector) {
this._defaultOffset3D = Cartesian3.clone(vector, new Cartesian3());
}
}
});
// Initialize the static property.
EntityView.defaultOffset3D = new Cartesian3(-14000, 3500, 3500);
var scratchHeadingPitchRange = new HeadingPitchRange();
var scratchCartesian = new Cartesian3();
/**
* Should be called each animation frame to update the camera
* to the latest settings.
* @param {JulianDate} time The current animation time.
* @param {BoundingSphere} [boundingSphere] bounding sphere of the object.
*/
EntityView.prototype.update = function(time, boundingSphere) {
//>>includeStart('debug', pragmas.debug);
Check.defined('time', time);
//>>includeEnd('debug');
var scene = this.scene;
var ellipsoid = this.ellipsoid;
var sceneMode = scene.mode;
if (sceneMode === SceneMode.MORPHING) {
return;
}
var entity = this.entity;
var positionProperty = entity.position;
if (!defined(positionProperty)) {
return;
}
var objectChanged = entity !== this._lastEntity;
var sceneModeChanged = sceneMode !== this._mode;
var camera = scene.camera;
var updateLookAt = objectChanged || sceneModeChanged;
var saveCamera = true;
if (objectChanged) {
var viewFromProperty = entity.viewFrom;
var hasViewFrom = defined(viewFromProperty);
if (!hasViewFrom && defined(boundingSphere)) {
// The default HPR is not ideal for high altitude objects so
// we scale the pitch as we get further from the earth for a more
// downward view.
scratchHeadingPitchRange.pitch = -CesiumMath.PI_OVER_FOUR;
scratchHeadingPitchRange.range = 0;
var position = positionProperty.getValue(time, scratchCartesian);
if (defined(position)) {
var factor = 2 - 1 / Math.max(1, Cartesian3.magnitude(position) / ellipsoid.maximumRadius);
scratchHeadingPitchRange.pitch *= factor;
}
camera.viewBoundingSphere(boundingSphere, scratchHeadingPitchRange);
this.boundingSphere = boundingSphere;
updateLookAt = false;
saveCamera = false;
} else if (!hasViewFrom || !defined(viewFromProperty.getValue(time, this._offset3D))) {
Cartesian3.clone(EntityView._defaultOffset3D, this._offset3D);
}
} else if (!sceneModeChanged && this._mode !== SceneMode.SCENE2D) {
Cartesian3.clone(camera.position, this._offset3D);
}
this._lastEntity = entity;
this._mode = sceneMode;
updateTransform(this, camera, updateLookAt, saveCamera, positionProperty, time, ellipsoid);
};
export default EntityView;