shader-stream-2018-08-08.glsl

#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 texNoise;
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

#define iTime fGlobalTime
#define pi acos(-1.)

float noise(vec2 p)
{
  return fract(sin(dot(p, vec2(12.43243, 4.58479)))*1234.4556);
}

float scene(vec3 p)
{
  p.x = abs(p.x);
  return min(
    1+p.y,
    1-p.x
  ) + texture(texChecker, p.xz*.25+p.yz*.25).r*.2;
}

vec2 rotate(vec2 a, float b)
{
  float c = cos(b);
  float s = sin(b);
  return vec2(
    a.x * c - a.y * s,
    a.x * s + a.y * c
  );
}

vec4 laser(vec4 color, vec2 uv)
{
  uv -= .5;
  float w = clamp(pow(.1/length(uv),3.),0,30);
  return color* w*.2;
}

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 cam = vec3(0,0,iTime*5);
    vec3 dir = normalize(vec3(uv, 1));

  cam.x = sin(iTime)*.3;
  dir.xy = rotate(dir.xy, sin(iTime)*.1);

  float t = 0;
  for(int i = 0; i < 64;++i)
  {
    t += scene(cam + dir * t)*.5;
  }
  vec3 h = cam + dir*t;

  vec2 o = vec2(.001, 0);
  vec3 n = normalize(vec3(
    scene(h+o.xyy)-scene(h-o.xyy),
    scene(h+o.yxy)-scene(h-o.yxy),
    scene(h+o.yyx)-scene(h-o.yyx)
  ));

  //n = normalize(cross(dFdy(h), dFdx(h)));

  out_color.rgb = fract(h*1);
  out_color.rgb = n*.5+.5;

  out_color = vec4(max(0,dot(n, vec3(.2,1,.1)))*.4+.05);

  out_color /= t*.3;

  {
    vec4 red = vec4(1,.1,.1,1);
    vec4 green = vec4(.1,1,.1,1);
    vec2 luv = vec2(
      .3/length(dir.xy),
      atan(dir.x, dir.y)/pi*.5
    );
    out_color += laser(red, fract(luv*vec2(.01,1)+vec2(-iTime*3,-.1)));
    out_color += laser(green, fract(luv*vec2(.01,1)+vec2(iTime*3+.5,.1)));
  }

  if (h.y > abs(h.x))
  {
    out_color = vec4(step(.995,noise(gl_FragCoord.xy)));
  }

  //out_color = laser(vec2(gl_FragCoord.x / v2Resolution.x, gl_FragCoord.y / v2Resolution.y));
}