Class: CatmullRomSpline

CatmullRomSpline

new CatmullRomSpline(options)

A Catmull-Rom spline is a cubic spline where the tangent at control points, except the first and last, are computed using the previous and next control points. Catmull-Rom splines are in the class C1.
Parameters:
Name Type Description
options Object Object with the following properties:
Properties
Name Type Attributes Description
times Array.<Number> An array of strictly increasing, unit-less, floating-point times at each point. The values are in no way connected to the clock time. They are the parameterization for the curve.
points Array.<Cartesian3> The array of Cartesian3 control points.
firstTangent Cartesian3 <optional>
 The tangent of the curve at the first control point. If the tangent is not given, it will be estimated.
lastTangent Cartesian3 <optional>
 The tangent of the curve at the last control point. If the tangent is not given, it will be estimated.
Source:
See:
Throws:
Example
// spline above the earth from Philadelphia to Los Angeles
var spline = new Cesium.CatmullRomSpline({
    times : [ 0.0, 1.5, 3.0, 4.5, 6.0 ],
    points : [
        new Cesium.Cartesian3(1235398.0, -4810983.0, 4146266.0),
        new Cesium.Cartesian3(1372574.0, -5345182.0, 4606657.0),
        new Cesium.Cartesian3(-757983.0, -5542796.0, 4514323.0),
        new Cesium.Cartesian3(-2821260.0, -5248423.0, 4021290.0),
        new Cesium.Cartesian3(-2539788.0, -4724797.0, 3620093.0)
    ]
});

var p0 = spline.evaluate(times[i]);         // equal to positions[i]
var p1 = spline.evaluate(times[i] + delta); // interpolated value when delta < times[i + 1] - times[i]

Members

(readonly) firstTangent :Cartesian3

The tangent at the first control point.
Type:
Source:

(readonly) lastTangent :Cartesian3

The tangent at the last control point.
Type:
Source:

(readonly) points :Array.<Cartesian3>

An array of Cartesian3 control points.
Type:
Source:

(readonly) times :Array.<Number>

An array of times for the control points.
Type:
  • Array.<Number>
Source:

Methods

evaluate(time, resultopt) → {Cartesian3}

Evaluates the curve at a given time.
Parameters:
Name Type Attributes Description
time Number The time at which to evaluate the curve.
result Cartesian3 <optional>
 The object onto which to store the result.
Source:
Throws:
time must be in the range [t0, tn], where t0 is the first element in the array times and tn is the last element in the array times.
Type
DeveloperError
Returns:
The modified result parameter or a new instance of the point on the curve at the given time.
Type
Cartesian3

findTimeInterval(time) → {Number}

Finds an index i in times such that the parameter time is in the interval [times[i], times[i + 1]].
Parameters:
Name Type Description
time Number The time.
Source:
Throws:
time must be in the range [t0, tn], where t0 is the first element in the array times and tn is the last element in the array times.
Type
DeveloperError
Returns:
The index for the element at the start of the interval.
Type
Number