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SteppedSpline

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

由表示阶跃函数的分段常数组成的样条线。 A spline that is composed of piecewise constants representing a step function.
名称 Name 类型 Type 说明 Description
options object 具有以下属性的对象： Object with the following properties:
名称 Name 类型 Type 说明 Description
times Array.<number> 每个点的严格递增、无单位浮点时间数组。这些值与时钟时间没有任何关系。它们是曲线的参数化。 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> 控制点数组。 The array of control points.
抛出： Throws:
  • DeveloperError : points.length must be greater than or equal to 2.
  • DeveloperError ：times.length必须等于points.length。 : times.length must be equal to points.length.
示例： Example:
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]);
另见： See:

成员 Members

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

控制点数组。 An array of control points.

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

控制点的时间数组。 An array of times for the control points.

方法 Methods

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

将给定时间限制为样条线覆盖的时间段。 Clamps the given time to the period covered by the spline.
名称 Name 类型 Type 说明 Description
time number 时间。 The time.
返回： Returns:
时间，固定在动画期间。 The time, clamped to the animation period.

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

评估给定时间的曲线。 Evaluates the curve at a given time.
名称 Name 类型 Type 说明 Description
time number 评估曲线的时间。 The time at which to evaluate the curve.
result Cartesian3 | Quaternion 可选 optional 用于存储结果的对象。 The object onto which to store the result.
返回： Returns:
修改后的结果参数或给定时间曲线上点的新实例。 The modified result parameter or a new instance of the point on the curve at the given time.
抛出： Throws:
  • DeveloperError : 时间必须在范围内 : time must be in the range [t0, tn], 其中 , where t0 是数组中的第一个元素 is the first element in the array times and tn 是数组中的最后一个元素 is the last element in the array times.

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

查找索引 Finds an index i in times 这样参数 such that the parameter time 是在区间内 is in the interval [times[i], times[i + 1]].
名称 Name 类型 Type 说明 Description
time number 时间。 The time.
startIndex number 开始搜索的索引。 The index from which to start the search.
返回： Returns:
间隔开始处的元素的索引。 The index for the element at the start of the interval.
抛出： Throws:
  • DeveloperError : 时间必须在范围内 : time must be in the range [t0, tn], 其中 , where t0 是数组中的第一个元素 is the first element in the array times and tn 是数组中的最后一个元素 is the last element in the array times.

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

将给定时间包裹到样条线覆盖的时间段。 Wraps the given time to the period covered by the spline.
名称 Name 类型 Type 说明 Description
time number 时间。 The time.
返回： Returns:
时间，围绕着更新的动画。 The time, wrapped around to the updated animation.
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