gain
Ken Perlin's famous gain function.
This is really just Perlin's bias function doubled, scaled and remapped into an S-curve.
See gain_fast for a speedy alternative.
NOTE: This function is dependent on bias().
gain(g,t) Returns a value t shifted towards 0 or 1 by a certain degree g resulting in an S-curve.
/*
** Usage:
** gain(g,t)
**
** Arguments:
** g gain, real
** t value, real
**
** Returns:
** If (t) varies over the [0,1] interval, then
** the result also varies over that interval.
** The zero and one endpoints of the interval
** are mapped onto themselves. Regardless of
** the value of (g), all gain functions return
** 0.5 when (t) is 0.5. Above and below 0.5 the
** gain function consists of two scaled-down
** bias curves forming an S-shaped curve.
**
** Dependencies:
** bias()
**
** GMLscripts.com
*/
{
if (argument1 < 0.5) return bias(1-argument0,2*argument1)/2;
else return 1 - bias(1-argument0,2-2*argument1)/2;
}
** Usage:
** gain(g,t)
**
** Arguments:
** g gain, real
** t value, real
**
** Returns:
** If (t) varies over the [0,1] interval, then
** the result also varies over that interval.
** The zero and one endpoints of the interval
** are mapped onto themselves. Regardless of
** the value of (g), all gain functions return
** 0.5 when (t) is 0.5. Above and below 0.5 the
** gain function consists of two scaled-down
** bias curves forming an S-shaped curve.
**
** Dependencies:
** bias()
**
** GMLscripts.com
*/
{
if (argument1 < 0.5) return bias(1-argument0,2*argument1)/2;
else return 1 - bias(1-argument0,2-2*argument1)/2;
}
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Projects: 4
Related: bias, bias_fast, boxstep, clamp, gain, gain_fast, gammacorrect, lerp, pulse, smoothstep, spline, spline4, step
Contributor: xot
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