highp float sinemap(highp float t0, highp float K, highp float tau){
       precision highp float;
       float v=0.0;
       v=t0+tau-(K/(3.1415926535897932384626433832795))*sin(t0*6.283185307179586476925286766559);
       return mod(v,1.0);
      }

int periodSineMap(highp float K, highp float tau){
        precision highp float;
	    float t=0.9576058000303126299572702894819;
	    for (int i=0;i<10000;i++){
	     t=sinemap(t,K,tau);
	    }
	    float ival=t;
	    int period=-1;
	    for (int j=0;j<257;j++){
	     t=sinemap(t,K,tau);
	     if ((t>ival-0.000001)&&(t<ival+0.000001)) {period=j+1; break;}
	    }
        return period;
       }

uniform highp vec4 parameters;

void main(void){
      precision highp float;
      float xd = gl_FragCoord.y/((1024.0)*parameters.p)+(parameters.q)/1024.0;
      float yd = gl_FragCoord.x/((1024.0)*parameters.s)+(parameters.t)/1024.0;
      int dif=periodSineMap(xd,yd);

if ((dif==-1)||(dif>256))  gl_FragColor=vec4(0.0,0.0,0.2,1);
      else{
       float d1=mod(float(dif)/33.0,1.0);
       float d2=mod(float(dif)/128.0,1.0);
       float d3=mod(float(dif)/64.0,1.0);
       gl_FragColor=vec4(d1,d2,d3,1);

gl_FragColor=vec4(d1,d2,d3,1);
       }
       }

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