// Seung Joon Choi
// http://epicure.graffity.net
// epicure@hanmail.net
// 2005.10.14.

float LOG05 = -0.693137180;

float step(float a, float x)
{
  return x >= a ? 1 : 0;
}

float smoothstep(float a, float b, float x)
{
  if(x < a) return 0;
  if(x >= b) return 1;
  x = (x - a) / (b - a);
  return x*x*(3-2*x);
}

float pulse(float a, float b, float fuzz, float x)
{
  return smoothstep(a, a + fuzz, x) - smoothstep(b - fuzz, b, x);
}

float clamp(float x, float a, float b)
{
  return (x < a ? a : (x > b ? b : x));
}

float boxstep(float a, float b, float x)
{
  return clamp((x - a) / (b - a), 0, 1);
}

float mod(float a, float b)
{
  int n = (int)(a/b);
  
  a -= n * b;
  if(a < 0) a += b;
  return a;
}

float bias(float b, float x)
{
    return pow(x, (float)Math.log(b)/LOG05);
}

float gain(float g, float x)
{
    if (x < 0.5)
        return bias(1-g, 2*x)/2;
    else
        return 1 - bias(1-g, 2 - 2*x)/2;
}

float gammacorrect(float gamma, float x)
{
  return pow(x, 1 / gamma);
}

float repeat(float x, float freq)
{
  return mod(x * freq, 1.0);
}