JT-CIM-SDK/packages/Widgets/SceneEffects/Weather.js

/* 引入Cesium */
// import * as Cesium from 'Cesium';

/**
 * 天气场景
 */
class Weather {
	/**
	 * 默认初始化
	 * @param {Object} viewer 三维场景
	 */
	constructor(viewer) {
		if (!viewer) throw new Cesium.DeveloperError('no viewer object!');
		this._viewer = viewer;
	}

	/**
	 * 雨天特效
	 * @ignore 忽略注释，注释不生成Doc
	 */
	_initRain() {
		this.rainStage = new Cesium.PostProcessStage({
			name: 'jt_rain',
			fragmentShader: this._rain(),
			uniforms: {
				tiltAngle: () => {
					return this.tiltAngle;
				},
				rainSize: () => {
					return this.rainSize;
				},
				rainSpeed: () => {
					return this.rainSpeed;
				}
			}
		});
		this._viewer.scene.postProcessStages.add(this.rainStage);
	}

	/**
	 * 雪天特效
	 * @ignore 忽略注释，注释不生成Doc
	 */
	_initSnow() {
		this.snowStage = new Cesium.PostProcessStage({
			name: 'jt_snow',
			fragmentShader: this._snow(),
			uniforms: {
				snowSize: () => {
					return this.snowSize;
				},
				snowSpeed: () => {
					return this.snowSpeed;
				}
			}
		});
		this._viewer.scene.postProcessStages.add(this.snowStage);
	}

	/**
	 * 雾天特效
	 * @ignore 忽略注释，注释不生成Doc
	 */
	_initFog() {
		this.fogStage = new Cesium.PostProcessStage({
			name: 'jt_fog',
			fragmentShader: this._fog(),
			uniforms: {
				visibility: () => {
					return this.visibility;
				},
				fogColor: () => {
					return this.color;
				}
			}
		});
		this._viewer.scene.postProcessStages.add(this.fogStage);
	}

	/**
	 * 雨天粒子效果
	 * @ignore 忽略注释，注释不生成Doc
	 */
	_rain() {
		return "uniform sampler2D colorTexture;\n\
	            varying vec2 v_textureCoordinates;\n\
	            uniform float tiltAngle;\n\
	            uniform float rainSize;\n\
	            uniform float rainSpeed;\n\
	            float hash(float x) {\n\
	                return fract(sin(x * 133.3) * 13.13);\n\
	            }\n\
	            void main(void) {\n\
	                float time = czm_frameNumber / rainSpeed;\n\
	                vec2 resolution = czm_viewport.zw;\n\
	                vec2 uv = (gl_FragCoord.xy * 2. - resolution.xy) / min(resolution.x, resolution.y);\n\
	                vec3 c = vec3(.6, .7, .8);\n\
	                float a = tiltAngle;\n\
	                float si = sin(a), co = cos(a);\n\
	                uv *= mat2(co, -si, si, co);\n\
	                uv *= length(uv + vec2(0, 4.9)) * rainSize + 1.;\n\
	                float v = 1. - sin(hash(floor(uv.x * 100.)) * 2.);\n\
	                float b = clamp(abs(sin(20. * time * v + uv.y * (5. / (2. + v)))) - .95, 0., 1.) * 20.;\n\
	                c *= v * b;\n\
	                gl_FragColor = mix(texture2D(colorTexture, v_textureCoordinates), vec4(c, 1), .5);\n\
	            }\n\
	            ";
	}

	/**
	 * 雪天粒子效果
	 * @ignore 忽略注释，注释不生成Doc
	 */
	_snow() {
		return "uniform sampler2D colorTexture;\n\
            varying vec2 v_textureCoordinates;\n\
            uniform float snowSpeed;\n\
                    uniform float snowSize;\n\
            float snow(vec2 uv,float scale)\n\
            {\n\
                float time=czm_frameNumber/snowSpeed;\n\
                float w=smoothstep(1.,0.,-uv.y*(scale/10.));if(w<.1)return 0.;\n\
                uv+=time/scale;uv.y+=time*2./scale;uv.x+=sin(uv.y+time*.5)/scale;\n\
                uv*=scale;vec2 s=floor(uv),f=fract(uv),p;float k=3.,d;\n\
                p=.5+.35*sin(11.*fract(sin((s+p+scale)*mat2(7,3,6,5))*5.))-f;d=length(p);k=min(d,k);\n\
                k=smoothstep(0.,k,sin(f.x+f.y)*snowSize);\n\
                return k*w;\n\
            }\n\
            void main(void){\n\
                vec2 resolution=czm_viewport.zw;\n\
                vec2 uv=(gl_FragCoord.xy*2.-resolution.xy)/min(resolution.x,resolution.y);\n\
                vec3 finalColor=vec3(0);\n\
                //float c=smoothstep(1.,0.3,clamp(uv.y*.3+.8,0.,.75));\n\
                float c=0.;\n\
                c+=snow(uv,30.)*.0;\n\
                c+=snow(uv,20.)*.0;\n\
                c+=snow(uv,15.)*.0;\n\
                c+=snow(uv,10.);\n\
                c+=snow(uv,8.);\n\
                c+=snow(uv,6.);\n\
                c+=snow(uv,5.);\n\
                finalColor=(vec3(c));\n\
                gl_FragColor=mix(texture2D(colorTexture,v_textureCoordinates),vec4(finalColor,1),.5);\n\
                }\n\
                ";
	}

	/**
	 * 雾天粒子效果
	 * @ignore 忽略注释，注释不生成Doc
	 */
	_fog() {
		return "uniform sampler2D colorTexture;\n\
	     uniform sampler2D depthTexture;\n\
	     uniform float visibility;\n\
	     uniform vec4 fogColor;\n\
	     varying vec2 v_textureCoordinates; \n\
	     void main(void) \n\
	     { \n\
	        vec4 origcolor = texture2D(colorTexture, v_textureCoordinates); \n\
	        float depth = czm_readDepth(depthTexture, v_textureCoordinates); \n\
	        vec4 depthcolor = texture2D(depthTexture, v_textureCoordinates); \n\
	        float f = visibility * (depthcolor.r - 0.3) / 0.2; \n\
	        if (f < 0.0) f = 0.0; \n\
	        else if (f > 1.0) f = 1.0; \n\
	        gl_FragColor = mix(origcolor, fogColor, f); \n\
	     }\n";
	}

	/**
	 * 移除雪天效果
	 * @ignore 忽略注释，注释不生成Doc
	 */
	_removeSnow() {
		if (!this._viewer || !this.snowStage) return;
		this._viewer.scene.postProcessStages.remove(this.snowStage);
		// this.snowStage.destroy();
		delete this.snowSize;
		delete this.snowSpeed;
	}

	/**
	 * 移除雨天效果
	 * @ignore 忽略注释，注释不生成Doc
	 */
	_removeRain() {
		if (!this._viewer || !this.rainStage) return;
		this._viewer.scene.postProcessStages.remove(this.rainStage);
		// this.rainStage.destroy();
		delete this.tiltAngle;
		delete this.rainSize;
		delete this.rainSpeed;
	}

	/**
	 * 移除雾天效果
	 * @ignore 忽略注释，注释不生成Doc
	 */
	_removeFog() {
		if (!this._viewer || !this.fogStage) return;
		this._viewer.scene.postProcessStages.remove(this.fogStage);
		// this.fogStage.destroy();
		delete this.visibility;
		delete this.color;
	}
}

/**
 * 通用对外公开函数 
 */
Object.assign(Weather.prototype, /** @lends Weather.prototype */ {

	/**
	 * 开启雨天特效
	 * @param {Object} options 具有以下属性:
	 * @param {Number} [options.tiltAngle=-0.6] 倾斜角度，负数向右，正数向左
	 * @param {Number} [options.rainSize=0.3] 雨大小
	 * @param {Number} [options.rainSpeed=-60.0] 雨速
	 */
	addRainEffect(options) {
		options = options || {};

		this.tiltAngle = Cesium.defaultValue(options.tiltAngle, -0.6);
		this.rainSize = Cesium.defaultValue(options.rainSize, 0.3);
		this.rainSpeed = Cesium.defaultValue(options.rainSpeed, 60.0);

		this._initRain();
	},

	/**
	 * 开启雪天特效
	 * @param {Object} options 具有以下属性:
	 * @param {Number} [options.snowSize=0.02] 雪大小，最好小于0.02，默认可不写，
	 * @param {Number} [options.snowSpeed=60.0] 雪速，默认可不写
	 */
	addSnowEffect(options) {
		options = options || {};

		this.snowSize = Cesium.defaultValue(options.snowSize, 0.02);
		this.snowSpeed = Cesium.defaultValue(options.snowSpeed, 60.0);

		this._initSnow();
	},

	/**
	 * 开启雾天特效
	 * @param {Object} options 具有以下属性:
	 * @param {Number} [options.visibility=-0.1] 
	 * @param {Number} [options.color=0.3] 
	 * @param {Number} [options.show] 
	 */
	addFogEffect(options) {
		options = options || {};

		this.visibility = Cesium.defaultValue(options.visibility, 0.1);
		this.color = Cesium.defaultValue(options.color, new Cesium.Color(0.8, 0.8, 0.8, 0.5));
		this._show = Cesium.defaultValue(options.show, !0);

		this._initFog();
	},

	/**
	 * 移除天气特效
	 */
	removeEffect() {
		if (this.snowStage) {
			this._removeSnow();
		}
		if (this.rainStage) {
			this._removeRain();
		}
		if (this.fogStage) {
			this._removeFog();
		}
	}
});

export default Weather;