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Add Spline::sample_with_key and Spline::clamped_sample_with_key.

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This commit is contained in:
Dimitri Sabadie
2019-09-30 12:49:36 +02:00
parent 336c1c7e80
commit cae599e0d7
4 changed files with 56 additions and 17 deletions
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9
CHANGELOG.md
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@ -1,3 +1,12 @@
# 2.1
> Mon Sep 30th 2019
- Add `Spline::sample_with_key` and `Spline::clamped_sample_with_key`. Those methods allow one to
perform the regular `Spline::sample` and `Spline::clamped_sample` but also retreive the base
key that was used to perform the interpolation. The key can be inspected to get the base time,
interpolation, etc. The next key is also returned, if present.
# 2.0.1
> Tue Sep 24th 2019

2
Cargo.toml
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@ -1,6 +1,6 @@
[package]
name = "splines"
version = "2.0.1"
version = "2.1.0"
license = "BSD-3-Clause"
authors = ["Dimitri Sabadie <dimitri.sabadie@gmail.com>"]
description = "Spline interpolation made easy"

58
src/spline.rs
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@ -69,7 +69,8 @@ impl<T, V> Spline<T, V> {
self.0.is_empty()
}
/// Sample a spline at a given time.
/// Sample a spline at a given time, returning the interpolated value along with its associated
/// key.
///
/// The current implementation, based on immutability, cannot perform in constant time. This means
/// that sampling’s processing complexity is currently *O(log n)*. It’s possible to achieve *O(1)*
@ -84,7 +85,7 @@ impl<T, V> Spline<T, V> {
/// you’re near the beginning of the spline or its end, ensure you have enough keys around to make
/// the sampling.
///
pub fn sample(&self, t: T) -> Option<V>
pub fn sample_with_key(&self, t: T) -> Option<(V, &Key<T, V>, Option<&Key<T, V>>)>
where T: Additive + One + Trigo + Mul<T, Output = T> + Div<T, Output = T> + PartialOrd,
V: Interpolate<T> {
let keys = &self.0;
@ -95,14 +96,17 @@ impl<T, V> Spline<T, V> {
Interpolation::Step(threshold) => {
let cp1 = &keys[i + 1];
let nt = normalize_time(t, cp0, cp1);
Some(if nt < threshold { cp0.value } else { cp1.value })
let value = if nt < threshold { cp0.value } else { cp1.value };
Some((value, cp0, Some(cp1)))
}
Interpolation::Linear => {
let cp1 = &keys[i + 1];
let nt = normalize_time(t, cp0, cp1);
let value = Interpolate::lerp(cp0.value, cp1.value, nt);
Some(Interpolate::lerp(cp0.value, cp1.value, nt))
Some((value, cp0, Some(cp1)))
}
Interpolation::Cosine => {
@ -110,8 +114,9 @@ impl<T, V> Spline<T, V> {
let cp1 = &keys[i + 1];
let nt = normalize_time(t, cp0, cp1);
let cos_nt = (T::one() - (nt * T::pi()).cos()) / two_t;
let value = Interpolate::lerp(cp0.value, cp1.value, cos_nt);
Some(Interpolate::lerp(cp0.value, cp1.value, cos_nt))
Some((value, cp0, Some(cp1)))
}
Interpolation::CatmullRom => {
@ -124,8 +129,9 @@ impl<T, V> Spline<T, V> {
let cpm0 = &keys[i - 1];
let cpm1 = &keys[i + 2];
let nt = normalize_time(t, cp0, cp1);
let value = Interpolate::cubic_hermite((cpm0.value, cpm0.t), (cp0.value, cp0.t), (cp1.value, cp1.t), (cpm1.value, cpm1.t), nt);
Some(Interpolate::cubic_hermite((cpm0.value, cpm0.t), (cp0.value, cp0.t), (cp1.value, cp1.t), (cpm1.value, cpm1.t), nt))
Some((value, cp0, Some(cp1)))
}
}
@ -134,18 +140,30 @@ impl<T, V> Spline<T, V> {
let cp1 = &keys[i + 1];
let nt = normalize_time(t, cp0, cp1);
if let Interpolation::Bezier(v) = cp1.interpolation {
Some(Interpolate::cubic_bezier(cp0.value, u, v, cp1.value, nt))
} else {
Some(Interpolate::quadratic_bezier(cp0.value, u, cp1.value, nt))
}
let value =
if let Interpolation::Bezier(v) = cp1.interpolation {
Interpolate::cubic_bezier(cp0.value, u, v, cp1.value, nt)
} else {
Interpolate::quadratic_bezier(cp0.value, u, cp1.value, nt)
};
Some((value, cp0, Some(cp1)))
}
Interpolation::__NonExhaustive => unreachable!(),
}
}
/// Sample a spline at a given time with clamping.
/// Sample a spline at a given time.
///
pub fn sample(&self, t: T) -> Option<V>
where T: Additive + One + Trigo + Mul<T, Output = T> + Div<T, Output = T> + PartialOrd,
V: Interpolate<T> {
self.sample_with_key(t).map(|(v, _, _)| v)
}
/// Sample a spline at a given time with clamping, returning the interpolated value along with its
/// associated key.
///
/// # Return
///
@ -155,22 +173,23 @@ impl<T, V> Spline<T, V> {
/// # Error
///
/// This function returns [`None`] if you have no key.
pub fn clamped_sample(&self, t: T) -> Option<V>
pub fn clamped_sample_with_key(&self, t: T) -> Option<(V, &Key<T, V>, Option<&Key<T, V>>)>
where T: Additive + One + Trigo + Mul<T, Output = T> + Div<T, Output = T> + PartialOrd,
V: Interpolate<T> {
if self.0.is_empty() {
return None;
}
self.sample(t).or_else(move || {
self.sample_with_key(t).or_else(move || {
let first = self.0.first().unwrap();
if t <= first.t {
Some(first.value)
let second = if self.0.len() >= 2 { Some(&self.0[1]) } else { None };
Some((first.value, &first, second))
} else {
let last = self.0.last().unwrap();
if t >= last.t {
Some(last.value)
Some((last.value, &last, None))
} else {
None
}
@ -178,6 +197,13 @@ impl<T, V> Spline<T, V> {
})
}
/// Sample a spline at a given time with clamping.
pub fn clamped_sample(&self, t: T) -> Option<V>
where T: Additive + One + Trigo + Mul<T, Output = T> + Div<T, Output = T> + PartialOrd,
V: Interpolate<T> {
self.clamped_sample_with_key(t).map(|(v, _, _)| v)
}
/// Add a key into the spline.
pub fn add(&mut self, key: Key<T, V>) where T: PartialOrd {
self.0.push(key);

4
tests/mod.rs
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@ -16,6 +16,8 @@ fn step_interpolation_f32() {
assert_eq!(spline.sample(0.9), Some(10.));
assert_eq!(spline.sample(1.), None);
assert_eq!(spline.clamped_sample(1.), Some(10.));
assert_eq!(spline.sample_with_key(0.2), Some((10., &start, Some(&end))));
assert_eq!(spline.clamped_sample_with_key(1.), Some((10., &end, None)));
}
#[test]
@ -31,6 +33,8 @@ fn step_interpolation_f64() {
assert_eq!(spline.sample(0.9), Some(10.));
assert_eq!(spline.sample(1.), None);
assert_eq!(spline.clamped_sample(1.), Some(10.));
assert_eq!(spline.sample_with_key(0.2), Some((10., &start, Some(&end))));
assert_eq!(spline.clamped_sample_with_key(1.), Some((10., &end, None)));
}
#[test]