VEX port of easings.net

easings.h

#ifndef __easing_h
#define __easing_h

/*
 * A straightforward port of the great easing function summary at https://easings.net/
 * Original lib by Andrey Sitnik (Twitter: @sitnikcode) and Ivan Solovev (Twitter: @gosolivs)
 * 
 * To install place this file inside $HOME/HoudiniX.X.XXX/vex/include/
 * ($HIP/vex/include and $HFS/vex/include are also possible)
 *
 * Include from within a wrangle with #include <easings.h>
 */

float easeInSine(float x) {
    return 1 - cos((x * PI) / 2);
}

float easeOutSine(float x) {
    return sin((x * PI) / 2);
}

float easeInOutSine(float x) {
  return -(cos(PI * x) - 1) / 2;
}

float easeInQuad(float x) {
  return x * x;
}

float easeOutQuad(float x) {
  return 1 - (1 - x) * (1 - x);
}

float easeInOutQuad(float x) {
  return x < 0.5 ? 2 * x * x : 1 - pow(-2 * x + 2, 2) / 2;
}

float easeInCubic(float x) {
  return x * x * x;
}

float easeOutCubic(float x) {
  return 1 - pow(1 - x, 3);
}

float easeInOutCubic(float x) {
  return x < 0.5 ? 4 * x * x * x : 1 - pow(-2 * x + 2, 3) / 2;
}

float easeInQuart(float x) {
  return x * x * x * x;
}

float easeOutQuart(float x) {
  return 1 - pow(1 - x, 4);
}

float easeInOutQuart(float x) {
  return x < 0.5 ? 8 * x * x * x * x : 1 - pow(-2 * x + 2, 4) / 2;
}

float easeInQuint(float x) {
  return x * x * x * x * x;
}

float easeOutQuint(float x) {
  return 1 - pow(1 - x, 5);
}

float easeInOutQuint(float x) {
  return x < 0.5 ? 16 * x * x * x * x * x : 1 - pow(-2 * x + 2, 5) / 2;
}

float easeInExpo(float x) {
  return x == 0 ? 0 : pow(2, 10 * x - 10);
}

float easeOutExpo(float x) {
  return x == 1 ? 1 : 1 - pow(2, -10 * x);
}

float easeInOutExpo(float x) {
  return x == 0
  ? 0
  : x == 1
  ? 1
  : x < 0.5 ? pow(2, 20 * x - 10) / 2
  : (2 - pow(2, -20 * x + 10)) / 2;
}

float easeInCirc(float x) {
  return 1 - sqrt(1 - pow(x, 2));
}

float easeOutCirc(float x) {
  return sqrt(1 - pow(x - 1, 2));
}

float easeInOutCirc(float x) {
  return x < 0.5
  ? (1 - sqrt(1 - pow(2 * x, 2))) / 2
  : (sqrt(1 - pow(-2 * x + 2, 2)) + 1) / 2;
}

float easeInBack(float x) {
  float c1 = 1.70158;
  float c3 = c1 + 1;

  return c3 * x * x * x - c1 * x * x;
}

float easeOutBack(float x) {
  float c1 = 1.70158;
  float c3 = c1 + 1;

  return 1 + c3 * pow(x - 1, 3) + c1 * pow(x - 1, 2);
}

float easeInOutBack(float x) {
  float c1 = 1.70158;
  float c2 = c1 * 1.525;

  return x < 0.5
  ? (pow(2 * x, 2) * ((c2 + 1) * 2 * x - c2)) / 2
  : (pow(2 * x - 2, 2) * ((c2 + 1) * (x * 2 - 2) + c2) + 2) / 2;
}

float easeInElastic(float x) {
  float c4 = (2 * PI) / 3;
  
  return x == 0
  ? 0
  : x == 1
  ? 1
  : -pow(2, 10 * x - 10) * sin((x * 10 - 10.75) * c4);
}

float easeOutElastic(float x) {
  float c4 = (2 * PI) / 3;
  
  return x == 0
  ? 0
  : x == 1
  ? 1
  : pow(2, -10 * x) * sin((x * 10 - 0.75) * c4) + 1;
}

float easeInOutElastic(float x) {
  float c5 = (2 * PI) / 4.5;
  
  return x == 0
  ? 0
  : x == 1
  ? 1
  : x < 0.5
  ? -(pow(2, 20 * x - 10) * sin((20 * x - 11.125) * c5)) / 2
  : (pow(2, -20 * x + 10) * sin((20 * x - 11.125) * c5)) / 2 + 1;
}

float easeOutBounce(float arg_x) {
  float n1 = 7.5625;
  float d1 = 2.75;
  float x = arg_x;

  if (x < 1 / d1) {
    return n1 * x * x;
  } else if (x < 2 / d1) {
    return n1 * (x -= 1.5 / d1) * x + 0.75;
  } else if (x < 2.5 / d1) {
    return n1 * (x -= 2.25 / d1) * x + 0.9375;
  } else {
    return n1 * (x -= 2.625 / d1) * x + 0.984375;
  }
}

float easeInBounce(float x) {
  return 1 - easeOutBounce(1 - x);
}

float easeInOutBounce(float x) {
  return x < 0.5
  ? (1 - easeOutBounce(1 - 2 * x)) / 2
  : (1 + easeOutBounce(2 * x - 1)) / 2;
}

#endif