/**
 * @Description: 流动纹理/图片材质
 */
export default class FlowPictureMaterialProperty {
  constructor(options) {
    if(!FlowPictureMaterialProperty.prototype.hasOwnProperty('color')) {
      Object.defineProperties(FlowPictureMaterialProperty.prototype, {
        repeat: Cesium.createPropertyDescriptor('repeat'),
        color: Cesium.createPropertyDescriptor('color')
      })
    }
    
    // Cesium.FlowPictureMaterialProperty = FlowPictureMaterialProperty;
    Cesium.Material.FlowPictureMaterialProperty = 'FlowPictureMaterialProperty';
    Cesium.Material.FlowPictureMaterialType = 'FlowPictureMaterialType';
    Cesium.Material.FlowPictureMaterialSource =
      `
        czm_material czm_getMaterial(czm_materialInput materialInput)
        {
          czm_material material = czm_getDefaultMaterial(materialInput);
          vec2 st = repeat*materialInput.st;
          vec4 colorImage = texture2D(image, vec2(fract(st.s - time), st.t));
          material.alpha = colorImage.a * color.a;
          material.diffuse = (colorImage.rgb+color.rgb)/2.0;
          // material.alpha = colorImage.a;
          // material.diffuse = (colorImage.rgb+color.rgb)/1.0;
          return material;
        }
      `


    Cesium.Material._materialCache.addMaterial(Cesium.Material.FlowPictureMaterialType, {
      fabric: {
        type: Cesium.Material.FlowPictureMaterialType,
        uniforms: {
          color: new Cesium.Color(1.0, 0.0, 0.0, 1.0),
          time: 0,
          image: '',
          repeat: new Cesium.Cartesian2(100.0, 100.0),
        },
        source: Cesium.Material.FlowPictureMaterialSource
      },
      translucent: function (material) {
        return true;
      }
    })

    this._definitionChanged = new Cesium.Event();
    this._color = undefined;
    this._colorSubscription = undefined;
    this._repeat = undefined;
    this._repeatSubscription = undefined;
    this.image = options.image;
    this.color = new Cesium.Color.fromCssColorString(options.color || "rgba(4,253,231,0.87)");
    this.repeat = options.repeat;
    this.duration = options.duration;
    this._time = (new Date()).getTime();
  };

  get isConstant() {
    return false;
  }

  get definitionChanged() {
    return this._definitionChanged;
  }

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

  getValue(time, result) {
    if (!Cesium.defined(result)) {
      result = {};
    }
    result.time = (((new Date()).getTime() - this._time) % this.duration) / this.duration;
    result.color = Cesium.Property.getValueOrDefault(this._color, time, Cesium.Color.WHITE, result.color);
    // result.color = Cesium.Property.getValueOrClonedDefault(this._color, time, Cesium.Color.WHITE, result.color);
    result.image = this.image;
    result.repeat = Cesium.Property.getValueOrDefault(this.repeat);
    return result
  }

  equals(other) {
    return (this === other ||
      (other instanceof FlowPictureMaterialProperty &&
        Cesium.Property.equals(this._color, other._color)) &&
        Cesium.Property.equals(this.repeat, other._repeat)
    )
  }
}




// ? 如何使用
// import FlowPictureMaterialProperty from '@/utils/Material/FlowPictureMaterialProperty.js'

// material: new FlowPictureMaterialProperty({
//   color: new Cesium.Color(1.0, 0.0, 0.0, 1.0),
//   image: '/src/assets/images/cat.png',
//   duration: 3000,
// })