/
bounce.go
56 lines (46 loc) · 1.43 KB
/
bounce.go
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package easing
// ////////////////////////////////////////////////////////////////////////////////// //
// //
// Copyright (c) 2024 ESSENTIAL KAOS //
// Apache License, Version 2.0 <https://www.apache.org/licenses/LICENSE-2.0> //
// //
// ////////////////////////////////////////////////////////////////////////////////// //
// BounceIn accelerating from zero velocity
// https://easings.net/#easeInBounce
func BounceIn(t, b, c, d float64) float64 {
if t > d {
return c
}
return c - BounceOut(d-t, 0.0, c, d) + b
}
// BounceOut Decelerating to zero velocity
// https://easings.net/#easeOutBounce
func BounceOut(t, b, c, d float64) float64 {
if t > d {
return c
}
t /= d
switch {
case t < 1/2.75:
return c*(7.5625*t*t) + b
case t < 2/2.75:
t -= 1.5 / 2.75
return c*(7.5625*t*t+0.75) + b
case t < 2.5/2.75:
t -= 2.25 / 2.75
return c*(7.5625*t*t+0.9375) + b
}
t -= 2.625 / 2.75
return c*(7.5625*t*t+0.984375) + b
}
// BounceInOut acceleration until halfway, then deceleration
// https://easings.net/#easeInOutBounce
func BounceInOut(t, b, c, d float64) float64 {
if t > d {
return c
}
if t < d/2 {
return BounceIn(t*2, 0.0, c, d)*0.5 + b
}
return BounceOut(t*2-d, 0.0, c, d)*0.5 + c*0.5 + b
}