//This file is automatically rebuilt by the Cesium build process.
export default "uniform sampler2D colorTexture;\n\
 varying vec2 v_textureCoordinates; \n\
 \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\
\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 = 0.0;\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)); //屏幕上雪的颜色\n\
    gl_FragColor = mix(texture2D(colorTexture, v_textureCoordinates), vec4(finalColor,1), 0.5);  //将雪和三维场景融合\n\
    \n\
} ";