SteppedSpline
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new Cesium.SteppedSpline(options)
engine/Source/Core/SteppedSpline.js 41

A spline that is composed of piecewise constants representing a step function.
参数名称 类型 描述信息
options object Object with the following properties:
参数名称 类型 描述信息
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.<number> | Array.<Cartesian3> | Array.<Quaternion> The array of control points.
Throws:
使用示例:
const times = [ 0.0, 1.5, 3.0, 4.5, 6.0 ];
const spline = new Cesium.SteppedSpline({
    times : times,
    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)
    ]
});

const p0 = spline.evaluate(times[0]);
参考:

成员(属性)

readonly points : Array.<number>|Array.<Cartesian3>|Array.<Quaternion>
engine/Source/Core/SteppedSpline.js 91

An array of control points.

readonly times : Array.<number>
engine/Source/Core/SteppedSpline.js 77

An array of times for the control points.

方法

clampTime(time) → number
engine/Source/Core/SteppedSpline.js 129

Clamps the given time to the period covered by the spline.
参数名称 类型 描述信息
time number The time.
返回值:
The time, clamped to the animation period.

evaluate(time, result) → number|Cartesian3|Quaternion
engine/Source/Core/SteppedSpline.js 142

Evaluates the curve at a given time.
参数名称 类型 描述信息
time number The time at which to evaluate the curve.
result Cartesian3 | Quaternion 可选 The object onto which to store the result.
返回值:
The modified result parameter or a new instance of the point on the curve at the given time.
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.

findTimeInterval(time, startIndex) → number
engine/Source/Core/SteppedSpline.js 111

Finds an index i in times such that the parameter time is in the interval [times[i], times[i + 1]].
参数名称 类型 描述信息
time number The time.
startIndex number The index from which to start the search.
返回值:
The index for the element at the start of the interval.
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.

wrapTime(time) → number
engine/Source/Core/SteppedSpline.js 120

Wraps the given time to the period covered by the spline.
参数名称 类型 描述信息
time number The time.
返回值:
The time, wrapped around to the updated animation.
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