#define time iTime
#define depth 40.0
#define fogSize 25.0
#define seuil 4.0
#define steps 200.0
float fogCoef=1.0/(depth-fogSize);float PI=acos(-1.0);float random (in float x){return fract(sin(x)*1e4);}float noise(in vec3 p){const vec3 step=vec3(110.0,241.0,171.0);vec3 i=floor(p);vec3 f=fract(p);float n=dot(i,step);vec3 u=f*f*(3.0-2.0*f);return mix( mix(mix(random(n+ dot(step,vec3(0,0,0))),random(n+dot(step,vec3(1,0,0))),u.x),mix(random(n+ dot(step,vec3(0,1,0))),random(n+ dot(step,vec3(1,1,0))),u.x),u.y),mix(mix(random(n+ dot(step,vec3(0,0,1))),random(n+dot(step,vec3(1,0,1))),u.x),mix(random(n+ dot(step,vec3(0,1,1))),random(n+ dot(step,vec3(1,1,1))),u.x),u.y),u.z);}mat2 rot(float a){float ca=cos(a);float sa=sin(a);return mat2(ca,sa,-sa,ca);}float water(in vec3 p,vec3 centerPos,float scale,float radius){vec3 truc=vec3(p.x+sin(length(p*0.2)+time)*2.0,p.y+sin(length(p*0.2))*2.0,0.0);float coef=length(truc)-4.0;float c=1.0;float n1=1.0;float d=1.0;for(int i=0;i<8;++i){n1+=2.0/c*abs(noise((p*c-time*0.5*c*d)*scale));c*=2.0;d+=1.5;}return n1*coef;}float mapHyper(vec3 p){return water(p,vec3(0,0,0),0.3,0.1);}vec3 tunnel(vec3 p){vec3 off=vec3(0);off.x+=sin(p.z*0.2)*1.5;off.y+=sin(p.z*0.3)*1.3;return off;}vec3 getSkyColor(vec3 e){e.y=(e.y);e.y=max(e.y,0.0);return vec3(pow(1.0-e.y,2.0),1.0-e.y,0.6+(1.0-e.y)*0.4)*noise(e);}void mainImage(out vec4 fragColor,in vec2 fragCoord){vec2 uv=vec2(fragCoord.x/iResolution.x,fragCoord.y/iResolution.y);uv-=0.5;uv/=vec2(iResolution.y/iResolution.x,1);vec3 s=vec3(-1.0,-1.0,-3);float t2=(time*1.5);s.xz *=rot(sin(t2)*0.015);vec3 t=vec3(0,0,0);s-=tunnel(s);t-=tunnel(t);s.x+=cos(t2*0.2)*1.0*sin(time*0.01);s.y+=sin(t2*0.2)*1.0*sin(time*0.01+10.0);vec3 cz=normalize(t-s);vec3 cx=normalize(cross(cz,vec3(0,1,0)));vec3 cy=normalize(cross(cz,cx));vec3 r=normalize(uv.x*cx+uv.y*cy+cz*0.7);vec3 p=s;float c=0.0;for(int i=0;i<int(steps);++i){float mH;mH=mapHyper(p);c+=mH;if(c>seuil)break;p+=r*(mH-seuil)*0.09;}vec3 col=vec3(0);float fresnel;vec3 reflected;vec2 off=vec2(0.05,0.0);vec3 zVect=vec3(0.0,0.0,1.0);vec3 n=normalize(mapHyper(p)-vec3(mapHyper(p-off.xyy),mapHyper(p-off.yxy),mapHyper(p-off.yyx)));col=mix(vec3(0.2,0.3,0.4),vec3(0.1,0.365,0.441),(abs(1.0+dot(n,s)*pow(dot(zVect,r),5.0))));fresnel=clamp(1.0-dot(n,s),0.05,0.75);reflected=getSkyColor(abs(reflect(r,n)));col=mix(col,reflected,(fresnel*reflected.x));float fog=clamp((length(p-s)-fogSize)*fogCoef,0.0,1.0);col=mix(col,vec3(0.85,0.85,0.85),fog);fragColor=vec4(col,1.0);}