#version 100

#ifdef GL_FRAGMENT_PRECISION_HIGH
precision highp float;
precision highp int;
#else
precision mediump float;
precision mediump int;
#endif

/*struct Precise {
  float mantissa, exponent;
};
Precise Precise_make (inout Precise precise) {
  float extra_exp = ceil(log2(abs(precise.mantissa)));
  precise.mantissa /= exp2(extra_exp);
  precise.exponent += extra_exp;
  return precise;
}
Precise Precise_create (const in float n) {
  Precise precise;
  precise.mantissa = n;
  precise.exponent = 0.0;
  return Precise_make(precise);
}
Precise Precise_create (in float mantissa, in float exponent) {
  Precise precise;
  precise.mantissa = mantissa;
  precise.exponent = exponent;
  return Precise_make(precise);
}
Precise Precise_create (in Precise n) {
  Precise precise;
  precise.mantissa = n.mantissa;
  precise.exponent = n.exponent;
  return Precise_make(precise);
}
void Precise_plusEquals (inout Precise a, in Precise b) {
  a.mantissa += b.mantissa * exp2(b.exponent - a.exponent);
  Precise_make(a);
}
Precise Precise_plus (in Precise a, in Precise b) {
  Precise result = Precise_create(a);
  Precise_plusEquals(result, b);
  return result;
}
void Precise_minusEquals (inout Precise a, in Precise b) {
  b.mantissa = -b.mantissa;
  Precise_plusEquals(a, b);
  b.mantissa = -b.mantissa;
  Precise_make(a);
}
Precise Precise_minus (in Precise a, in Precise b) {
  Precise result = Precise_create(a);
  Precise_minusEquals(result, b);
  return result;
}
void Precise_multiplyEquals (inout Precise a, in Precise b) {
  a.mantissa *= b.mantissa;
  a.exponent += b.exponent;
  Precise_make(a);
}
Precise Precise_multiply (in Precise a, in Precise b) {
  Precise result = Precise_create(a);
  Precise_multiplyEquals(result, b);
  return result;
}
float Precise_toFloat (in Precise a) {
  return a.mantissa * exp2(a.exponent);
}*/

uniform vec2 uCanvasSize;
uniform vec2 uOffset;
uniform float uScale;

vec4 calc (vec2 texCoord) {
  /* Mandelbrot Fractal Attempt
  float x = texCoord.x, y = texCoord.y;
  float v = 10000.0, j = 10000.0;
  
  for (int i = 0; i < 100; ++i) {
    float xtemp = x*x - y*y + texCoord.x;
    y = y*x + x*y + texCoord.y;
    x = xtemp;
    v = min(v, abs(x*x + y*y));
    j = min(j, abs(x*y));
    
    if ((x*x + y*y) > 4.0) {
      float d = (float(i) - (log(log(sqrt(x*x + y*y))) / log(2.0))) / 50.0;
      v = (1.0 - v) / 2.0;
      j = (1.0 - j) / 2.0;
      return vec4(d+j, d, d+v, 1);
    }
  }
  return vec4(0, 0, 0, 1);*/
  
  
  float x = 0.0, y = 0.0;
  float v = 10000.0, j = 10000.0;
  
  for (int i = 0; i < 100; ++i) {
    float xtemp = x*x - y*y + (texCoord.x + 1.0);
    y = 2.0 + x*y + (texCoord.y + 1.0);
    x = xtemp;
    v = min(v, abs(x*x + y*y));
    j = min(j, abs(x*y));
    
    if ((x*x + y*y) >= 8.0) {
      float d = (float(i) - (log(log(sqrt(x*x + y*y))) / log(2.0))) / 50.0;
      v = (1.0 - v) / 2.0;
      j = (1.0 - j) / 2.0;
      //return vec4(d, j, v, 1);
      //return vec4(1, 1, 1, 2) - vec4(d+j, d, d+v, 1); // Inverted
      return vec4(d+j, d, d+v, 1);
    }
  }
  //return vec4(0, 0, 0, 0);
  return vec4(0, 0, 0, 1);
  
  
  //return vec4(1.0 - length(vec2(-1.0, -1.0)-texCoord) / 2.0, (texCoord + vec2(1.0, 1.0)) / 2.0, 1.0);
}

void main (void) {
  vec2 texCoord = (gl_FragCoord.xy / uCanvasSize.xy) * 2.0 - vec2(1.0, 1.0);
  texCoord = (texCoord * uScale) + uOffset;
  gl_FragColor = calc(texCoord);
}