rounded_box

rounded_box.glsl

#version 150

uniform float time;
uniform vec2 resolution;
uniform vec2 mouse;
uniform vec3 spectrum;

uniform sampler2D texture0;
uniform sampler2D texture1;
uniform sampler2D texture2;
uniform sampler2D texture3;
uniform sampler2D prevFrame;
uniform sampler2D prevPass;

in VertexData
{
    vec4 v_position;
    vec3 v_normal;
    vec2 v_texcoord;
} inData;

out vec4 fragColor;

float roundedBox(vec2 p, vec3 d)
{
  float r   = d.z;
  d         *= 0.5;
  p         = abs(p);
  float oxy = length(vec2(d.x - d.z, d.y - d.z));
  float dx  = p.x - d.x;
  float dy  = p.y - d.y;
  float dxy = sqrt(0.5)*(p.x + p.y) - oxy; 
  float ds  = length(p - sqrt(0.5)*oxy + d.z) - r;
  float db  = max(max(dx, dy), dxy);
  return min(ds, db);
}

float df(vec2 p)
{
  return length(p) - 1.0;
}

void main(void)
{
  vec2 uv = -1. + 2. * inData.v_texcoord;
  uv.x *= resolution.x/resolution.y;

  float d = roundedBox(uv, vec3(1.0, 1.0, 0.1));

  vec3 col = vec3(0.0);

  float md = mod(d, 0.1);

  if (abs(md) < 0.01)
  {
    float h = 1.0/(abs(d) / 0.1);
    if (d < 0)
    {
      col = vec3(h, 0.25, 0.25);
    }
    else
    {
      col = vec3(0.25, 0.25, h);
    }
  }
  
  if (abs(d) < 0.01)
  {
    col = vec3(1.0);
  }  
  
  fragColor = vec4(col, 1.0);
}