#version 330 core


#ifdef GL_ES
precision mediump float;
#endif

// here i fixed

#extension GL_OES_standard_derivatives : enable

uniform float time;
uniform vec2 mouse;
uniform vec2 resolution;

uniform vec3      iResolution;           // viewport resolution (in pixels)
uniform float     iGlobalTime;           // shader playback time (in seconds)
uniform float     iTimeDelta;            // render time (in seconds)
uniform int       iFrame;                // shader playback frame
uniform float     iChannelTime[4];       // channel playback time (in seconds)
uniform vec3      iChannelResolution[4]; // channel resolution (in pixels)
uniform vec4      iMouse;                // mouse pixel coords. xy: current (if MLB down), zw: click
uniform vec4      iDate;                 // (year, month, day, time in seconds)
uniform float     iSampleRate;           // sound sample rate (i.e., 44100)
out vec4 color_out;

float noise(vec3 p) //Thx to Las^Mercury
{
  vec3 i = floor(p);
  vec4 a = dot(i, vec3(1., 57., 21.)) + vec4(0., 57., 21., 78.);
  vec3 f = cos((p-i)*acos(-1.))*(-.5)+.5;
  a = mix(sin(cos(a)*a),sin(cos(1.+a)*(1.+a)), f.x);
  a.xy = mix(a.xz, a.yw, f.y);
  return mix(a.x, a.y, f.z);
}

float sphere(vec3 p, vec4 spr)
{
  return length(spr.xyz-p) - spr.w;
}

float flame(vec3 p)
{
  float d = sphere(p*vec3(1.,.5,1.), vec4(.0,-1.,.0,1.));
  return d + (noise(p+vec3(.0,time*2.,.0)) + noise(p*3.+vec3(.0,time*11.,.0))*.5)*.25*(p.y) ;
}

float scene(vec3 p)
{
  return min(100.-length(p) , abs(flame(p)) );
}

vec4 raymarch(vec3 org, vec3 dir)
{
  float d = 0.0, glow = 0.0, eps = 0.02;
  vec3  p = org;
  bool glowed = false;
  
  for(int i=0; i<64; i++)
  {
    d = scene(p) + eps;
    p += d * dir;
    if( d>eps )
    {
      if(flame(p) < .0)
        glowed=true;
      if(glowed)
            glow = float(i)/64.;
    }
  }
  return vec4(p,glow);
}

void mainImage( out vec4 fragColor, in vec2 fragCoord )
{
  vec2 v = -1.0 + 2.0 * fragCoord.xy / resolution.xy;
  v.x *= resolution.x/resolution.y;
  
  vec3 org = vec3(0., -2., 4.);
  vec3 dir = normalize(vec3(v.x*1.6, -v.y, -1.5));
  
  vec4 p = raymarch(org, dir);
  float glow = p.w;
  
  vec4 col = mix(vec4(1.,.5,.1,1.), vec4(0.1,.5,1.,1.), p.y*.02+.4);
  
  fragColor = mix(vec4(0.), col, pow(glow*2.,4.));
  //fragColor = mix(vec4(1.), mix(vec4(1.,.5,.1,1.),vec4(0.1,.5,1.,1.),p.y*.02+.4), pow(glow*2.,4.));

}

void main( void ) {
  
  vec4 fragColor;
  
//  vec2 fragCoord = ( gl_FragCoord.xy / resolution.xy ) + mouse / 4.0;

  mainImage(fragColor, gl_FragCoord.xy);

  color_out = fragColor;
}