weird

weird.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 softBox(vec2 p, float sz)
{
  p *= p;
  p *= p;
  float l8 = dot(p, p);
  return pow(l8, 1.0/8.) - sz;
}

float sphere(vec2 p, float sz)
{
  return length(p) - sz;
}

float plane(vec2 p, vec2 n, float m)
{
  return dot(p, n) + m;
}

void rot(inout vec2 p, float a)
{
  float c = cos(a);
  float s = sin(a);
  p = vec2(c*p.x + s*p.y, -s*p.x + c*p.y);
}

#define PI                  3.141592654
#define TAU                 (2.0*PI)
#define PHI                 (.5*(1.+sqrt(5.)))

const vec2 n1 = normalize(vec2(-PHI+1.294, 1));
const vec2 n2 = normalize(vec2(1, -PHI));


void sphere_fold(inout vec2 z, inout float dz) 
{
  float fixed_radius2 = 1.9;
  float min_radius2 = 0.1;
    
  float r2 = dot(z, z);
  if(r2 < min_radius2) 
  {
    float temp = (fixed_radius2 / min_radius2);
    z *= temp;
    dz *= temp;
  }
  else if(r2 < fixed_radius2) 
  {
    float temp = (fixed_radius2 / r2);
    z *= temp;
    dz *= temp;
  }
}


vec2 sphereFold(vec2 p, vec2 c, float r)
{
  vec2 d = p - c;
  float l = length(d);
  if (l > r)
  {
    p = c + (r - tanh((l - r)/r))*normalize(d);
  }
  return p;
}

vec2 sphereFoldq(vec2 p, vec2 c, float r)
{
  vec2 d = p - c;
  float l = length(d);
  if (l < r)
  {
    p = c + (r + (r - l))*normalize(d);
  }
  return p;
}

float wheels(vec2 uv)
{
    uv *= 2;

    float t;

    vec2 n1 = n1;
    vec2 n2 = n2;
    
    rot(n2, time);

    t = dot(n2, uv)-1.5; if(t > 0) uv -= 2.0*t*n2;
    t = dot(n1, uv)-0.0; if(t > 0) uv -= 2.0*t*n1;
    uv = abs(uv);    
    t = dot(n1, uv); if(t > 0) uv -= 2.0*t*n1;
    uv = abs(uv);    
    t = dot(n1, uv); if(t > 0) uv -= 2.0*t*n1;
    //t = dot(n2, uv) - sqrt(0.04); if(t > 0) uv -= 2.0*t*n2;
    //uv = -abs(uv);    
    
    float d = softBox(uv - vec2(1,0), 0.25);
    d = min(d,plane(uv, normalize(vec2(1, 0.0)), -0.5));
    float dd = plane(uv, normalize(vec2(1, 0.0)), -1.4);
    dd = max(-dd, plane(uv, normalize(vec2(1, 0.0)), -1.5));
    d = min(dd, d);
    return d;
}

vec2 mod2(inout vec2 p, vec2 size) {
    vec2 c = floor((p + size*0.5)/size);
    p = mod(p + size*0.5,size) - size*0.5;
    return c;
}

float test(vec2 uv)
{
  uv *= 3.0;
  float sz = 1.0;
  float d = 1000.0;
  for(int i = 0; i < 8; ++i)
  {
    uv = abs(uv);
    float t;
    vec2 n1 = n1;
    vec2 n2 = n2;
    rot(n1, 0.05*sin(sqrt(2)*time));
    rot(n2, 0.05*sin(time));
    t = dot(n1, uv); if(t > 0) uv -= 2.0*t*n1;
    t = dot(n2, uv); if(t > 0) uv -= 2.0*t*n2;
    uv -= vec2(0.9)*sz;
    sz *= 0.8;
    d = min(d, sphere(uv, 1.3));
    d = min(d, -plane(uv, n2, 1));
  }
  return d+1.2;
}

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

    float d = test(uv);
    
    float p = mod(d, 0.1);
    
    vec3 col = abs(p) < 0.01 ? vec3(0.25, 0.5, exp(-15*d*d)) : vec3(0);
    if (d < 0) col.xz = col.zx;
    col = abs(d) < 0.02 ? vec3(1) : col;
   
    fragColor = vec4(col, 1);
}