3.セシウムの雨、雪、霧の天候シーンの影響

これらの効果を実現するには、cesiumのpostProcessStagesインターフェイスを介してfragmentShaderを変更します

addsnow() {
    
    
	//删除
      if (this.snow) this.viewer.scene.postProcessStages.remove(this.snow)
      this.snow = new Cesium.PostProcessStage({
    
    
        name: 'czm_snow',
        fragmentShader:
         '\n\
          uniform sampler2D colorTexture;\n\
          varying vec2 v_textureCoordinates;\n\
          float snow(vec2 uv,float scale)\n\
          {\n\
          float time = czm_frameNumber / 60.0;\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)*0.01);\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 = 0.0;\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), 0.5); \n\
          }'
      })

      this.viewer.scene.postProcessStages.add(this.snow)
    },

シェーダー

//雨
 '\n\
   uniform sampler2D colorTexture;\n\
     varying vec2 v_textureCoordinates;\n\
     float hash(float x)\n\
     {\n\
      return fract(sin(x*133.3)*13.13);\n\
     }\n\
     void main(void){\n\
       float time = czm_frameNumber / 60.0;\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=-.4;\n\
     float si=sin(a),co=cos(a);\n\
     uv*=mat2(co,-si,si,co);\n\
     uv*=length(uv+vec2(0,4.9))*.3+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), 0.5);\n\
 	}'

//雪
'\n\
    uniform sampler2D colorTexture;\n\
    varying vec2 v_textureCoordinates;\n\
    float snow(vec2 uv,float scale)\n\
    {\n\
    float time = czm_frameNumber / 60.0;\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)*0.01);\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 = 0.0;\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), 0.5); \n\
	 }'
 
//雾
'\n\
   uniform sampler2D colorTexture;\n\
        uniform sampler2D depthTexture;\n\
        varying vec2 v_textureCoordinates;\n\
        void main(void)\n\
        {\n\
           vec4 origcolor=texture2D(colorTexture, v_textureCoordinates);\n\
            vec4 fogcolor=vec4(0.8,0.8,0.8,0.5);\n\
            float depth = czm_readDepth(depthTexture, v_textureCoordinates);\n\
            vec4 depthcolor=texture2D(depthTexture, v_textureCoordinates);\n\
            float f=(depthcolor.r-0.7)/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\
		}'