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:
|
Throws:
-
DeveloperError : points.length must be greater than or equal to 2.
-
DeveloperError : times.length must be equal to points.length.
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>
An array of control points.
An array of times for the control points.
方法
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
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]
, wheret0
is the first element in the arraytimes
andtn
is the last element in the arraytimes
.
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]
, wheret0
is the first element in the arraytimes
andtn
is the last element in the arraytimes
.
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.