import * as Cesium from 'cesium'
/**
 * 定义Cesium材质对象
 */
class ImageTrailMaterial {
	constructor(options = {}) {
		this._definitionChanged = new Cesium.Event()
		this._color = void 0
		this._colorSubscription = void 0
		this._speed = void 0
		this._speedSubscription = void 0
		this._image = void 0
		this._imageSubscription = void 0
		this._repeat = void 0
		this._repeatSubscription = void 0
		this.color = options.color || Cesium.Color.fromBytes(0, 0, 255, 255)
		this.speed = options.speed || 1
		this.image = options.image
		this.repeat = new Cesium.Cartesian2(options.repeat?.x || 1, options.repeat?.y || 1)
	}

	get isConstant() {
		return false
	}

	get definitionChanged() {
		return this._definitionChanged
	}

	getType() {
		return Cesium.Material.ImageTrailMaterialType
	}

	getValue(time, result) {
		if (!result) {
			result = {}
		}
		result.color = Cesium.Property.getValueOrUndefined(this._color, time)
		result.image = Cesium.Property.getValueOrUndefined(this._image, time)
		result.repeat = Cesium.Property.getValueOrUndefined(this._repeat, time)
		result.speed = this._speed
		return result
	}

	equals(other) {
		return (
			this === other ||
			(other instanceof ImageTrailMaterial &&
				Cesium.Property.equals(this._color, other._color) &&
				Cesium.Property.equals(this._image, other._image) &&
				Cesium.Property.equals(this._repeat, other._repeat) &&
				Cesium.Property.equals(this._speed, other._speed))
		)
	}
}

Object.defineProperties(ImageTrailMaterial.prototype, {
	color: Cesium.createPropertyDescriptor('color'),
	speed: Cesium.createPropertyDescriptor('speed'),
	image: Cesium.createPropertyDescriptor('image'),
	repeat: Cesium.createPropertyDescriptor('repeat'),
})
//材质类型
Cesium.Material.ImageTrailMaterialType = 'PolylineImageTrail'
//添加材质到缓冲区中
Cesium.Material._materialCache.addMaterial(Cesium.Material.ImageTrailMaterialType, {
	fabric: {
		type: Cesium.Material.ImageTrailMaterialType,
		//uniform变量
		uniforms: {
			color: new Cesium.Color(1.0, 0.0, 0.0, 0.7),
			image: Cesium.Material.DefaultImageId,
			speed: 1,
			repeat: new Cesium.Cartesian2(1, 1),
		},
		//
		source: `
                    uniform sampler2D image; 
                    uniform float speed;
                    uniform vec4 color;
                    uniform vec2 repeat;
                    
                    czm_material czm_getMaterial(czm_materialInput materialInput){
                        czm_material material=czm_getDefaultMaterial(materialInput);
                        vec2 st=repeat * materialInput.st;
                        float time=fract(czm_frameNumber*speed/1000.);
                        vec4 colorImage=texture(image,vec2(fract(st.s-time),st.t)); // 修改 texture2D 为 texture
                        material.alpha = colorImage.a * color.a;
                        material.diffuse = (colorImage.rgb+color.rgb)/2.0;
                        return material;
                    }
                    `,
	},
	translucent: function () {
		return true
	},
})
export default ImageTrailMaterial

//之前的航线材质编写
// source: `
// uniform sampler2D image;
// uniform float speed;
// uniform vec4 color;
// uniform vec2 repeat;

// czm_material czm_getMaterial(czm_materialInput materialInput){
//     czm_material material=czm_getDefaultMaterial(materialInput);
//     vec2 st=repeat * materialInput.st;
//     float time=fract(czm_frameNumber*speed/1000.);
//     // st.s是横轴方向运动,st.t是纵轴，
//     // vec2(fract(st.s-time),st.t)是横轴按照时间变化而变化，纵轴保持正常不变化
//     vec4 colorImage=texture2D(image,vec2(fract(st.s-time),st.t));
//     vec4 fragColor;
//     fragColor.rgb=color.rgb / 1.0;
//     if(color.a==0.){
//         material.alpha=colorImage.a;
//         material.diffuse=colorImage.rgb;
//     }else{
//         material.alpha=colorImage.a*color.a;
//         material.diffuse=max(color.rgb*material.alpha*3.,color.rgb);
//     }
//     return material;
// }
// `