CatmullRomSpline

CatmullRomSpline

new

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 Argument Description
options.times Array 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.
options.points Array The array of Cartesian3 control points.
options.firstTangent Cartesian3 <optional>
The tangent of the curve at the first control point. If the tangent is not given, it will be estimated.
options.lastTangent Cartesian3 <optional>
The tangent of the curve at the last control point. If the tangent is not given, it will be estimated.
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]
See:
Source:

Members

:DeveloperError

Finds an index i in times such that the parameter time is in the interval [times[i], times[i + 1]].

<readonly> :Cartesian3

The tangent at the first control point.

<readonly> :Cartesian3

The tangent at the last control point.

<readonly> :Array

An array of Cartesian3 control points.

<readonly> :Array

An array of times for the control points.

Methods

Evaluates the curve at a given time.

Parameters:
Name Type Argument Description
time Number The time at which to evaluate the curve.
result Cartesian3 <optional>
The object onto which to store the result.
Throws:
DeveloperError : 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.
Returns:
Cartesian3 The modified result parameter or a new instance of the point on the curve at the given time.