Cesium 自定义Material 系列 （九）

对于扫描线效果 我们先定义一下他的interface, 方便使用的人知道他的调用参数

export interface PMaterialScan{

color?: any,

speed?: number,

}

对于扫描线我们叫 MaterialScan

```javascript

import {MaterialProperty} from "./MaterialProperty";

const defaultOption: PMaterialScan = {

color: new Cesium.Color(1.0, 0.0, 0.0, 0.7),

speed: 10,

}

//扫描

export class MaterialScan extends MaterialProperty{

protected _getType(option: any): string {

return "MaterialScan"

}

constructor(option=defaultOption) {

super(MaterialScan.prototype, defaultOption, option);

}

protected getSource(option: any): string {

return `

uniform vec4 color;

uniform float speed;

czm_material czm_getMaterial(czm_materialInput materialInput){

czm_material material = czm_getDefaultMaterial(materialInput);

vec2 st = materialInput.st;

float time = fract(czm_frameNumber * speed / 1000.0);

material.diffuse = color.rgb;

material.alpha = color.a * fract(st.s-time);

 更多参考 https://xiaozhuanlan.com/topic/3270685194