1 uniform float t; 2 varying vec4 vTexCoord; 3 4 const float BLOWUP=66.0; /* 86.0 */ 5 const float MAXSTEPSHIFT=8.0; /* 6.0 */ 6 const int MAXITERS=34; /* 26 */ 7 8 const float pi=3.1415926535; 9 10 float sum(vec3 v) { return v.x+v.y+v.z; } 11 12 int func(vec3 pos,float stepshift) 13 { 14 vec3 v2=abs(fract(pos)-vec3(0.5,0.5,0.5))/2.0; 15 float r=0.0769*sin(t*-0.0708); 16 float blowup=BLOWUP/pow(2.0,stepshift+8.0); 17 18 if(sum(v2)-0.1445+r<blowup) return 1; 19 v2=vec3(0.25,0.25,0.25)-v2; 20 if(sum(v2)-0.1445-r<blowup) return 2; 21 22 int hue; 23 float width; 24 if(abs(sum(v2)-3.0*r-0.375)<0.03846) 25 { 26 width=0.1445; 27 hue=4; 28 } 29 else 30 { 31 width=0.0676; 32 hue=3; 33 } 34 35 if(sum(abs(v2.zxy-v2.xyz))-width<blowup) return hue; 36 37 return 0; 38 } 39 40 void main() 41 { 42 float x=vTexCoord.x*0.5; 43 float y=vTexCoord.y*0.5; 44 45 float sin_a=sin(t*0.00564); 46 float cos_a=cos(t*0.00564); 47 48 vec3 dir=vec3(x,-y,0.33594-x*x-y*y); 49 dir=vec3(dir.y,dir.z*cos_a-dir.x*sin_a,dir.x*cos_a+dir.z*sin_a); 50 dir=vec3(dir.y,dir.z*cos_a-dir.x*sin_a,dir.x*cos_a+dir.z*sin_a); 51 dir=vec3(dir.y,dir.z*cos_a-dir.x*sin_a,dir.x*cos_a+dir.z*sin_a); 52 53 vec3 pos=vec3(0.5,1.1875,0.875)+vec3(1.0,1.0,1.0)*0.0134*t; 54 55 float stepshift=MAXSTEPSHIFT; 56 57 if(fract(pow(x,y)*t*1000.0)>0.5) pos+=dir/pow(2.0,stepshift); 58 else pos-=dir/pow(2.0,stepshift); 59 60 int i=0; 61 int c; 62 do 63 { 64 c=func(pos,stepshift); 65 if(c>0) 66 { 67 stepshift+=1.0; 68 pos-=dir/pow(2.0,stepshift); 69 } 70 else 71 { 72 if(stepshift>0.0) stepshift-=1.0; 73 pos+=dir/pow(2.0,stepshift); 74 i++; 75 } 76 } 77 while(stepshift<MAXSTEPSHIFT&&i<MAXITERS); 78 79 80 vec3 col; 81 if(c==0) col=vec3(0.0,0.0,0.0); 82 else if(c==1) col=vec3(1.0,0.5,0.0); 83 else if(c==2) col=vec3(0.0,1.0,0.0); 84 else if(c==3) col=vec3(1.0,1.0,1.0); 85 else if(c==4) col=vec3(0.5,0.5,0.5); 86 87 gl_FragColor=vec4(col*(1.0-(float(i)-stepshift)/32.0),1.0); 88 } 89
