precision mediump float;
#define GLSLIFY 1
// Common uniforms
uniform vec2 u_resolution;
uniform vec2 u_mouse;
uniform float u_time;
uniform float u_frame;

// Common varyings
varying vec3 v_position;
varying vec3 v_normal;

/*
 *  Calculates the diffuse factor produced by the light illumination

precision mediump float;
varying vec2 v_texCoord;
uniform sampler2D u_texture;
uniform vec2 u_resolution;
uniform float u_amplitude; // px
uniform float u_frequency; // waves across image
uniform int   u_direction; // 0=horizontal, 1=vertical, 2=radial

void main() {
  vec2 uv = v_texCoord;
  float amp = u_amplitude / u_resolution.x;
  float freq = u_frequency * 6.28318;
  float offset = 0.0;

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);
}