precision mediump float;

#endif

​

varying vec2 vTexCoord;

​

uniform sampler2D texture;

uniform float noise;

uniform float wobble;

​

// https://iquilezles.org/articles/distfunctions2d/

float sdBox( in vec2 p, in vec2 b ) {

    vec2 d = abs(p)-b;

    return length(max(d,0.0)) + min(max(d.x,d.y),0.0);

}

float sdEquilateralTriangle( in vec2 p, in float r ) {

    const float k = sqrt(3.0);

    p.x = abs(p.x) - r;

    p.y = p.y + r/k;

    if( p.x+k*p.y>0.0 ) p = vec2(p.x-k*p.y,-k*p.x-p.y)/2.0;

    p.x -= clamp( p.x, -2.0*r, 0.0 );

    return -length(p)*sign(p.y);

}

//---

​

void main() {

  vec2 uv = vTexCoord;

  uv.y = 1.0 - uv.y;

  // vec2 offset = vec2(noise * 0.05, 0.0);

  // vec2 offset = vec2(.009, 0.009);

  vec2 offset = vec2(noise,noise);

  vec2 _uv = uv.xy * 2.0 - 1.0;

  // _uv.y = .25 - _uv.y;

  // if (sdBox(uv.xy, vec2(.5,.25)) < 0.25)

  if (sdEquilateralTriangle(_uv, .7) < .25+wobble) 

    offset = vec2(0.1, 0.1);

  // vec2 offset = vec2(noise, noise);

  vec3 col;

  col.r = texture2D(texture, uv + offset).r;

  col.g = texture2D(texture, uv).g;

  col.b = texture2D(texture, uv - offset).b;

  gl_FragColor = vec4(col, 1.0);

}