/*
    动态墙材质
    color 颜色
    duration 持续时间 毫秒
    trailImage 贴图地址
*/
function DynamicWallMaterialProperty(options) {
	this._definitionChanged = new Cesium.Event();
	this._color = undefined;
	this._colorSubscription = undefined;
	this.color = options.color || Color.BLUE;
	this.duration = options.duration || 1000;
	this.trailImage = options.trailImage;
	this._time = (new Date()).getTime();
}

/**
 * 带方向的墙体
 * @param {*} options.get:true/false
 * @param {*} options.count:数量 
 * @param {*} options.direction:vertical/standard
 * @param {*} options.order:+/-
 */
function _getDirectionWallShader(options) {
	if (options && options.get) {
		var materail = "czm_material czm_getMaterial(czm_materialInput materialInput)\n\
      {\n\
          czm_material material = czm_getDefaultMaterial(materialInput);\n\
          vec2 st = materialInput.st;";
		if (options.direction == "vertical") { //（由下到上）
			materail += "vec4 colorImage = texture2D(image, vec2(fract(st.s), fract(float(" + options.count + ")*st.t" + options.order + " time)));\n\ ";
		} else { //（逆时针）
			materail += "vec4 colorImage = texture2D(image, vec2(fract(float(" + options.count + ")*st.s " + options.order + " time), fract(st.t)));\n\ ";
		}
		//泛光
		materail += "vec4 fragColor;\n\
          fragColor.rgb = (colorImage.rgb+color.rgb) / 1.0;\n\
          fragColor = czm_gammaCorrect(fragColor);\n\
          material.diffuse = colorImage.rgb;\n\
          material.alpha = colorImage.a;\n\
          material.emission = fragColor.rgb;\n\
          return material;\n\
      }";
		return materail
	}
}

Object.defineProperties(DynamicWallMaterialProperty.prototype, {
	isConstant: {
		get: function() {
			return false;
		}
	},
	definitionChanged: {
		get: function() {
			return this._definitionChanged;
		}
	},
	color: Cesium.createPropertyDescriptor('color')
});

var MaterialType = 'wallType' + parseInt(Math.random() * 1000);
DynamicWallMaterialProperty.prototype.getType = function(time) {
	return MaterialType;
};

DynamicWallMaterialProperty.prototype.getValue = function(time, result) {
	if (!Cesium.defined(result)) {
		result = {};
	}
	result.color = Cesium.Property.getValueOrClonedDefault(this._color, time, Cesium.Color.WHITE, result.color);
	result.image = this.trailImage;
	if (this.duration) {
		result.time = (((new Date()).getTime() - this._time) % this.duration) / this.duration;
	}
	viewer.scene.requestRender();
	return result;
};

DynamicWallMaterialProperty.prototype.equals = function(other) {
	return this === other ||
		(other instanceof DynamicWallMaterialProperty &&
			Cesium.Property.equals(this._color, other._color))
};

Cesium.Material._materialCache.addMaterial(MaterialType, {
	fabric: {
		type: MaterialType,
		uniforms: {
			color: new Cesium.Color(1.0, 0.0, 0.0, 0.5),
			image: Cesium.Material.DefaultImageId,
			time: -20
		},
		source: _getDirectionWallShader({
			get: true,
			count: 3.0,
			direction: 'vertical',
			order: '-'
		})
	},
	translucent: function(material) {
		return true;
	}
});
Cesium.DynamicWallMaterialProperty = DynamicWallMaterialProperty;

export default DynamicWallMaterialProperty;