[NO BUG] GLSL Shaders crash vid io

Code:
#version 100

#ifdef GL_ES

precision mediump float;

#endif

#define PI 3.14159

#define MAX_ITER 20.



uniform vec2 u_resolution;

uniform float u_time;

uniform float u_modulator1;

uniform float u_modulator2;

uniform float u_modulator3;

uniform float u_modulator4;

uniform float u_modulator5;

uniform float u_modulator6;



const vec3 a1 = vec3(0.5, 0.5, 0.5);

const vec3 b1 = vec3(0.5, 0.5, 0.5);

const vec3 c1 = vec3(2.0, 1.0, 0.0);

const vec3 d1 = vec3(0.50, 0.20, 0.25);



const vec3 a2 = vec3(0.5, 0.5, 0.5);

const vec3 b2 = vec3(0.5, 0.5, 0.5);

const vec3 c2 = vec3(1.0, 1.0, 1.0);

const vec3 d2 = vec3(0.00, 0.33, 0.67);

mat2 rotate(float _angle){

    return mat2(cos(_angle),-sin(_angle),

                sin(_angle),cos(_angle));

}

mat2 scale(vec2 _scale){

    return mat2(_scale.x,0.0,

                0.0,_scale.y);

}

vec3 palette(in float t, in vec3 a, in vec3 b, in vec3 c, vec3 d)

{

    return a + b*cos( 6.283185*(c*t+d) );

}



float check_step(float i, float z, float step_id) {

    float is_i = step(0.1, i);

    

    return (is_i * i) + ((1.-is_i) * (step(200., z) * step_id));

}



float julia(vec2 uv){

 float j=0.;

 float i=0.;

  vec2 c=vec2(-0.70176,-0.3842);

  for (float i=0.;i<MAX_ITER;i++){

      uv=vec2(uv.x*uv.x-uv.y*uv.y,2.0*uv.x*uv.y)+c;

      j=check_step(j, length(uv), i);

  }

  return j;

}





float hash(vec2 p)

{

    p  = fract( p*0.6180339887 );

    p *= 25.0;

    return fract( p.x*p.y*(p.x+p.y) );

}



float noise( in vec2 x )

{

    vec2 p = floor(x);

    vec2 f = fract(x);

    f = f*f*(3.0-2.0*f);

    float a = hash(p+vec2(0,0));

    float b = hash(p+vec2(1,0));

    float c = hash(p+vec2(0,1));

    float d = hash(p+vec2(1,1));

    return mix(mix( a, b,f.x), mix( c, d,f.x),f.y);

}



float fbm ( in vec2 _st) {

    float v = 0.0;

    float a = 0.5;

    const vec2 shift = vec2(100.0);

    const mat2 rot = mat2(cos(0.5), sin(0.5),

                    -sin(0.5), cos(0.50));

    

    v += a * noise(_st);

    _st = rot * _st * 2.0 + shift;

    a *= 0.5;

    v += a * noise(_st);

    _st = rot * _st * 2.0 + shift;

    a *= 0.5;

    v += a * noise(_st);

    _st = rot * _st * 2.0 + shift;

    a *= 0.5;

    v += a * noise(_st);

    _st = rot * _st * 2.0 + shift;

    a *= 0.5;

    v += a * noise(_st);

    _st = rot * _st * 2.0 + shift;

    a *= 0.5;

    v += a * noise(_st);

    _st = rot * _st * 2.0 + shift;

    a *= 0.5;

    v += a * noise(_st);



    return v;

}



vec3 smoke(vec2 st){

    vec3 color = vec3(0.0);



    vec2 q = vec2(0.);

    q.x = fbm( st + 0.00*u_time);

    q.y = fbm( st + vec2(1.0));



    vec2 r = vec2(0.);

    r.x = fbm( st + 1.0*q + vec2(1.7,9.2)+ 0.15*u_time );

    r.y = fbm( st + 1.0*q + vec2(8.3,2.8)+ 0.126*u_time);



    float f = fbm(st+r);



    color = mix(vec3(0.101961,0.619608,0.666667),

                vec3(0.666667,0.666667,0.498039),

                clamp((f*f)*4.0,0.0,1.0));



    color = mix(color,

                vec3(0.8,0.6,0.164706),

                clamp(length(q),0.0,1.0));



    color = mix(color,

                vec3(0.666667,1.,1.),

                clamp(length(r.x),0.0,1.0));



    return (f*f*f+.6*f*f+.5*f)*color;

}



float between(float start, float end, float p) {

    return step(start, p) * step(p, end);

}



void main(){

  vec2 uv=(((2.0*gl_FragCoord.xy)-u_resolution.xy)/u_resolution.y);

  vec2 uv2 = uv;



  uv2 *= rotate(-fract((u_time / 50.0) * (1.-u_modulator2)) * PI * 2.);

  uv *= rotate(fract((u_time / 10.0) * (1.-u_modulator2)) * PI * 2.);    

  uv *= scale(vec2(1.3 + (1.-u_modulator1) * 0.4));

  float foreground_start = (float(MAX_ITER) * ((0.5-u_modulator3)*0.5));

  float mandel = 1.;//julia(uv);

  

  vec3 color1 = palette(fbm(vec2(mandel/MAX_ITER, fract(u_time / 500.))*100.),a1,b1,c1,d1);

    

  vec3 middleground = color1; 

  vec3 smok = (smoke(uv2 * 15.) * 10.) + 0.3;

  vec3 background = smok * palette(length(uv2) / 3.,a2,b2,c2,d2) ;

  vec3 foreground = smok * palette((length(uv2) / 3.) + 0.6,a2,b2,c2,d2);



  gl_FragColor=vec4(background * between(1., foreground_start - 1., mandel), ((1. - u_modulator4))*0.5) + vec4(middleground * between(foreground_start, MAX_ITER, mandel), ((1. - u_modulator5))*0.5)+ vec4(foreground * between(0., .1, mandel), ((1. - u_modulator6))*0.5);

}