cesium水流特效代码

以下是一个使用Cesium实现水流特效的代码示例：

var viewer = new Cesium.Viewer('cesiumContainer');

// 创建水面
var waterSurface = viewer.entities.add({
    position: Cesium.Cartesian3.fromDegrees(-75.59777, 40.03883),
    name: 'Water surface',
    ellipse: {
        semiMinorAxis: 2000.0,
        semiMajorAxis: 2000.0,
        height: 0.0,
        material: new Cesium.ImageMaterialProperty({
            image: 'path/to/water-texture.png',
            repeat: new Cesium.Cartesian2(4,4)
        })
    }
});

// 创建水流
var waterFlow = viewer.entities.add({
    polyline: {
        positions: Cesium.Cartesian3.fromDegreesArray([
            -75.59777, 40.03883,
            -75.58777, 40.03883
        ]),
        width: 10,
        material: new Cesium.PolylineGlowMaterialProperty({
            color: Cesium.Color.BLUE,
            glowPower: 0.2
        })
    }
});

// 创建水流动画
var flowAnimation = viewer.clock.onTick.addEventListener(function(clock) {
    var time = clock.currentTime.secondsOfDay;
    var flowPositions = [
        -75.59777, 40.03883,
        -75.58777, 40.03883
    ];
    for (var i = 0; i < flowPositions.length; i += 2) {
        flowPositions[i] += Math.sin(time * 0.0005) * 0.0001;
        flowPositions[i + 1] += Math.cos(time * 0.0005) * 0.0001;
    }
    waterFlow.polyline.positions = Cesium.Cartesian3.fromDegreesArray(flowPositions);
});

这段代码使用Cesium创建了一个水面和一条水流，并通过动画使水流产生流动效果。其中，`Cesium.ImageMaterialProperty`用于设置水面的纹理，`Cesium.PolylineGlowMaterialProperty`用于设置水流的材质，`viewer.clock.onTick.addEventListener`用于监听时间变化并更新水流的位置。