#version 410 core

uniform float fGlobalTime; // in seconds
uniform vec2 v2Resolution; // viewport resolution (in pixels)

uniform sampler1D texFFT; // towards 0.0 is bass / lower freq, towards 1.0 is higher / treble freq
uniform sampler1D texFFTSmoothed; // this one has longer falloff and less harsh transients
uniform sampler1D texFFTIntegrated; // this is continually increasing
uniform sampler2D texChecker;
uniform sampler2D texKC;
uniform sampler2D texNoise;
uniform sampler2D texPegasus;
uniform sampler2D texTex1;
uniform sampler2D texTex2;
uniform sampler2D texTex3;
uniform sampler2D texTex4;

layout(location = 0) out vec4 out_color; // out_color must be written in order to see anything


float sphere(vec3 pos, float r)
{
  return length(pos) - r;
}

float box (vec3 t, vec3 m)
{
  return length(max(abs(t)-m,0.0));
}

float map (vec3 pos)
{ 
  float x = fGlobalTime;
  mat3 prout = mat3 (cos(x), -sin(x), 0., sin(x), cos(x), 0.,0., 0., 1.);
  pos = prout*pos;
  pos = mod(pos,2.)-1.;
  return max(sphere(vec3(pos),0.5),sphere(pos,1.0));
}

/*vec4 plas( vec2 v, float time )
{
  float c = 0.5 + sin( v.x * 10.0 ) + cos( sin( time + v.y ) * 20.0 );
  return vec4( sin(c * 0.2 + cos(time)), c * 0.15, cos( c * 0.1 + time / .4 ) * .25, 1.0 );
}*/
void main(void)
{
  vec2 uv = vec2(gl_FragCoord.x / v2Resolution.x, gl_FragCoord.y / v2Resolution.y);
  uv -= 0.5;
  uv /= vec2(v2Resolution.y / v2Resolution.x, 1);
  
  vec3 pos = vec3(0.0,0.0,-5.);
  vec3 dir = normalize(vec3(uv,1.0));

  for (float i=0; i<64; i++)
{
  float d = map(pos);
  if (d<0.001)
    break;
  pos += dir*d;
}
  /*vec2 m;
  m.x = atan(uv.x / uv.y) / 3.14;
  m.y = 1 / length(uv) * .2;
  float d = m.y;

  float f = texture( texFFT, d ).r * 100;
  m.x += sin( fGlobalTime ) * 0.1;
  m.y += fGlobalTime * 0.25;

  vec4 t = plas( m * 3.14, fGlobalTime ) / d;
  t = clamp( t, 0.0, 1.0 );*/
  out_color = vec4(pos,1.0);
}