simple-easing2 1.0.2

Set of simple easing functions
Documentation 
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const C1: f32 = 1.70158;
const C2: f32 = C1 * 1.525;
const C3: f32 = C1 + 1.0;

/// <https://easings.net/#easeInBack>
#[must_use]
#[inline(always)]
pub fn back_in(t: f32) -> f32 {
    (C3 * t * t).mul_add(t, -C1 * t * t)
}

/// <https://easings.net/#easeOutBack>
#[must_use]
#[inline(always)]
pub fn back_out(t: f32) -> f32 {
    C1.mul_add((t - 1.0).powi(2), C3.mul_add((t - 1.0).powi(3), 1.0))
}

/// <https://easings.net/#easeInOutBack>
#[must_use]
#[inline(always)]
pub fn back_in_out(t: f32) -> f32 {
    if t < 0.5 {
        ((2.0 * t).powi(2) * ((C2 + 1.0) * 2.0).mul_add(t, -C2)) / 2.0
    } else {
        2.0f32
            .mul_add(t, -2.0)
            .powi(2)
            .mul_add((C2 + 1.0).mul_add(t.mul_add(2.0, -2.0), C2), 2.0)
            / 2.0
    }
}