/*
 * @Description: 闪烁线材质
 * @Version: 1.0
 * @Author: Julian
 * @Date: 2022-03-30 16:40:09
 * @LastEditors: Julian
 * @LastEditTime: 2022-03-30 17:22:04
 */
class LineFlickerMaterialProperty {
  constructor(options) {
    this._definitionChanged = new Cesium.Event();
    this._color = undefined;
    this._speed = undefined;
    this.color = options.color;
    this.speed = options.speed;
  }

  get isConstant() {
    return false;
  }

  get definitionChanged() {
    return this._definitionChanged;
  }

  getType(time) {
    return Cesium.Material.LineFlickerMaterialType;
  }

  getValue(time, result) {
    if (!Cesium.defined(result)) {
      result = {};
    }

    result.color = Cesium.Property.getValueOrDefault(
      this._color,
      time,
      Cesium.Color.RED,
      result.color
    );
    result.speed = Cesium.Property.getValueOrDefault(
      this._speed,
      time,
      5.0,
      result.speed
    );
    return result;
  }

  equals(other) {
    return (
      this === other ||
      (other instanceof LineFlickerMaterialProperty &&
        Cesium.Property.equals(this._color, other._color) &&
        Cesium.Property.equals(this._speed, other._speed))
    );
  }
}

Object.defineProperties(LineFlickerMaterialProperty.prototype, {
  color: Cesium.createPropertyDescriptor("color"),
  speed: Cesium.createPropertyDescriptor("speed"),
});

Cesium.LineFlickerMaterialProperty = LineFlickerMaterialProperty;
Cesium.Material.LineFlickerMaterialProperty = "LineFlickerMaterialProperty";
Cesium.Material.LineFlickerMaterialType = "LineFlickerMaterialType";
Cesium.Material.LineFlickerMaterialSource = `
uniform vec4 color;
uniform float speed;
czm_material czm_getMaterial(czm_materialInput materialInput){
  czm_material material = czm_getDefaultMaterial(materialInput);
  float time = fract( czm_frameNumber  *  speed / 1000.0);
  vec2 st = materialInput.st;
  float scalar = smoothstep(0.5,1.0,time);
  material.diffuse = color.rgb * scalar;
  material.alpha = color.a * scalar ;
  return material;
}
`;

Cesium.Material._materialCache.addMaterial(
  Cesium.Material.LineFlickerMaterialType,
  {
    fabric: {
      type: Cesium.Material.LineFlickerMaterialType,
      uniforms: {
        color: new Cesium.Color(1.0, 0.0, 0.0, 1.0),
        speed: 5.0,
      },
      source: Cesium.Material.LineFlickerMaterialSource,
    },
    translucent: function (material) {
      return true;
    },
  }
);