sdk4.0/src/Obj/Materail/LineTextureMaterialProperty.js

/*
 * @Description: 流动线
 */
function LineTexture() {
  class LineTextureMaterialProperty {
    constructor(options) {
      this._definitionChanged = new Cesium.Event();
      this._image = undefined;
      this._color = undefined;
      this._imageW = undefined;
      this.image = options.image || "";
      this.color = new Cesium.Color.fromCssColorString(options.color || "rgba(255,255,255,1)");
      this.imageW = options.imageW || 1;
    }

    get isConstant() {
      return false;
    }

    get definitionChanged() {
      return this._definitionChanged;
    }

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

    getValue(time, result) {
      if (!Cesium.defined(result)) {
        result = {};
      }
      result.image = Cesium.Property.getValueOrDefault(
        this._image,
        time,
        "",
        result.image
      );
      result.color = Cesium.Property.getValueOrDefault(
        this._color,
        time,
        Cesium.Color.RED,
        result.color
      );
      result.imageW = Cesium.Property.getValueOrDefault(
        this._imageW,
        time,
        1,
        result.imageW
      );
      return result;
    }

    equals(other) {
      return (
        this === other ||
        (other instanceof LineTextureMaterialProperty &&
          Cesium.Property.equals(this._image, other._image) &&
          Cesium.Property.equals(this._color, other._color) &&
          Cesium.Property.equals(this._imageW, other._imageW))
      );
    }
  }

  Object.defineProperties(LineTextureMaterialProperty.prototype, {
    image: Cesium.createPropertyDescriptor("image"),
    color: Cesium.createPropertyDescriptor("color"),
    imageW: Cesium.createPropertyDescriptor("imageW"),
  });

  Cesium.LineTextureMaterialProperty = LineTextureMaterialProperty;
  Cesium.Material.LineTextureMaterialProperty = "LineTextureMaterialProperty";
  Cesium.Material.LineTextureMaterialType = "LineTextureMaterialType";
  Cesium.Material.LineTextureMaterialSource = `
        #extension GL_OES_standard_derivatives : enable
        czm_material czm_getMaterial(czm_materialInput materialInput)
        {
            czm_material m = czm_getDefaultMaterial(materialInput);


            vec2 st = materialInput.st * vec2(494/172, 1.0); // 横向重复两次
            vec2 uv = vec2(fract(st.s + uTime*0.1), st.t);
            // uv.y = mix(uv.y, 1.0-uv.y, step(0.5, fract(uTime))); // 周期性反转Y轴
            vec4 tex = texture(image, uv);
            m.diffuse =(tex.rgb+color.rgb)/2.0;
            m.alpha = tex.a * (1.0 - fract(st.t)) * color.a; // 顶部渐隐

            return m;
        }
       `;
  Cesium.Material._materialCache.addMaterial(
    Cesium.Material.LineTextureMaterialType,
    {
      fabric: {
        type: Cesium.Material.LineTextureMaterialType,
        uniforms: {
          color: new Cesium.Color(1.0, 1.0, 1.0, 1.0),
          image: '',
          imageW: 1,
          uTime: 1
        },
        source: Cesium.Material.LineTextureMaterialSource,
      },
      translucent: function (material) {
        return true;
      },
    }
  );
}

export { LineTexture }