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 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);
}