precision mediump float;
varying vec2 v_texcoord;

vec2 brickTile(vec2 _st, float _zoom){
    _st *= _zoom;
    if (fract(_st.y * 0.5) > 0.5){
        _st.x += 0.5;
    }
    return fract(_st);
}

float box(vec2 _st, vec2 _size){
    _size = vec2(0.5)-_size*0.5;
    vec2 uv = smoothstep(_size,_size+vec2(0.0001),_st);

precision mediump float;
varying vec2 v_texcoord;
#define PI 3.14159265358979323846

vec2 rotate2D(vec2 _st, float _angle){
  _st -= 0.5;
  _st =  mat2(cos(_angle),-sin(_angle),
              sin(_angle),cos(_angle)) * _st;
  _st += 0.5;
  return _st;
}

vec2 tile(vec2 _st, float _zoom){
  _st *= _zoom;

precision mediump float;
uniform vec2 resolution;
uniform float time;
float hash(vec2 p){ return fract(sin(dot(p, vec2(41.0, 289.0))) * 45758.5453); }
float noise(vec2 p){ vec2 i=floor(p), f=fract(p); f=f*f*(3.0-2.0*f); return mix(mix(hash(i),hash(i+vec2(1,0)),f.x),mix(hash(i+vec2(0,1)),hash(i+1.0),f.x),f.y); }
float fbm(vec2 p){ float v=0.0; float a=0.5; for(int i=0;i<5;i++){ v += a*noise(p); p*=2.05; a*=0.5; } return v; }
void main(){
  vec2 uv = gl_FragCoord.xy / resolution.xy;
  uv.x *= resolution.x / resolution.y;
  float n = fbm(uv * 3.0 + vec2(time * 0.035, -time * 0.02));
  float veins = sin((uv.x + n * 1.8) * 22.0);
  float line = smoothstep(0.72, 1.0, veins);
  vec3 stone = mix(vec3(0.08,0.09,0.11), vec3(0.78,0.82,0.86), n);
  vec3 vein = mix(vec3(0.02,0.025,0.035), vec3(0.9,0.75,0.55), line);

precision mediump float;
uniform float u_time;
varying vec2 v_texcoord;
#define PI 3.14159265358979323846

float rows = 10.0;

vec2 brickTile(vec2 _st, float _zoom){
  _st *= _zoom;
  if (fract(_st.y * 0.5) > 0.5){
      _st.x += 0.5;
  }
  return fract(_st);
}

precision mediump float;
uniform float u_time;
varying vec2 v_texcoord;
#define PI 3.14159265358979323846
#define TWO_PI 6.28318530717958647693

vec2 rotate2D(vec2 _st, float _angle){
  _st -= 0.5;
  _st =  mat2(cos(_angle),-sin(_angle),
              sin(_angle),cos(_angle)) * _st;
  _st += 0.5;
  return _st;
}

precision mediump float;
varying vec2 v_texcoord;
vec2 tile(vec2 _st, float _zoom){
  _st *= _zoom;
  return fract(_st);
}

float X(vec2 _st, float _width){
  float pct0 = smoothstep(_st.x-_width,_st.x,_st.y);
  pct0 *= 1.-smoothstep(_st.x,_st.x+_width,_st.y);

  float pct1 = smoothstep(_st.x-_width,_st.x,1.0-_st.y);
  pct1 *= 1.-smoothstep(_st.x,_st.x+_width,1.0-_st.y);

precision mediump float;
uniform float u_time;
varying vec2 v_texcoord;
#define PI 3.14159265358979323846
#define TWO_PI 6.28318530717958647693
#define PHI 1.618033988749894848204586834

vec2 radialTile(vec2 _st, vec2 _vel, float _zoom){
  vec2 toExtreme = vec2(0.5)-_st;
  vec2 polar = vec2( (PI+atan(toExtreme.y,toExtreme.x))/TWO_PI,   // Angle
                      log(length(toExtreme))*PHI*0.1);            // Radius
  polar *= _zoom;

  polar.y += _vel.y;

precision mediump float;
varying vec2 v_texcoord;
#define PI 3.14159265358979323846

float plotX(vec2 _st, float _pct,float _antia){
  return  smoothstep( _pct-_antia, _pct, _st.x) - 
          smoothstep( _pct, _pct+_antia, _st.x);
}

float plotY(vec2 _st, float _pct,float _antia){
  return  smoothstep( _pct-_antia, _pct, _st.y) - 
          smoothstep( _pct, _pct+_antia, _st.y);
}

precision mediump float;
uniform vec2 resolution;
uniform float time;
float hash(vec2 p){ return fract(sin(dot(p, vec2(13.13, 117.17))) * 43758.5453); }
float noise(vec2 p){ vec2 i=floor(p), f=fract(p); f=f*f*(3.0-2.0*f); return mix(mix(hash(i),hash(i+vec2(1,0)),f.x),mix(hash(i+vec2(0,1)),hash(i+1.0),f.x),f.y); }
void main(){
 vec2 uv = gl_FragCoord.xy / resolution.xy; uv.x *= resolution.x/resolution.y;
 float n = noise(uv*9.0) + 0.5*noise(uv*22.0);
 float rings = sin((uv.x + n*0.09 + 0.02*sin(uv.y*18.0)) * 55.0);
 float grain = smoothstep(-0.2, 1.0, rings);
 vec3 dark = vec3(0.22,0.10,0.035), light = vec3(0.72,0.38,0.13);
 gl_FragColor = vec4(mix(dark, light, grain) * (0.75 + 0.25*n), 1.0);
}