Struct EvenCore 

pub struct EvenCore<T> {
    pub domain: Interval,
    pub samples: Vec<T>,
}

The data core of a curve derived from evenly-spaced samples. The intention is to use this in addition to explicit or inferred interpolation information in user-space in order to implement curves using domain and sample_with.

The internals are made transparent to give curve authors freedom, but the provided constructor enforces the required invariants, and the methods maintain those invariants.

Example

// Let's make a curve that interpolates evenly spaced samples using either linear interpolation
// or step "interpolation" — i.e. just using the most recent sample as the source of truth.
enum InterpolationMode {
    Linear,
    Step,
}

// Linear interpolation mode is driven by a trait.
trait LinearInterpolate {
    fn lerp(&self, other: &Self, t: f32) -> Self;
}

// Step interpolation just uses an explicit function.
fn step<T: Clone>(first: &T, second: &T, t: f32) -> T {
    if t >= 1.0 {
        second.clone()
    } else {
        first.clone()
    }
}

// Omitted: Implementing `LinearInterpolate` on relevant types; e.g. `f32`, `Vec3`, and so on.

// The curve itself uses `EvenCore` to hold the evenly-spaced samples, and the `sample_with`
// function will do all the work of interpolating once given a function to do it with.
struct MyCurve<T> {
    core: EvenCore<T>,
    interpolation_mode: InterpolationMode,
}

impl<T> Curve<T> for MyCurve<T>
where
    T: LinearInterpolate + Clone,
{
    fn domain(&self) -> Interval {
        self.core.domain()
    }
     
    fn sample_unchecked(&self, t: f32) -> T {
        // To sample this curve, check the interpolation mode and dispatch accordingly.
        match self.interpolation_mode {
            InterpolationMode::Linear => self.core.sample_with(t, <T as LinearInterpolate>::lerp),
            InterpolationMode::Step => self.core.sample_with(t, step),
        }
    }
}

Fields

domain: Interval

The domain over which the samples are taken, which corresponds to the domain of the curve formed by interpolating them.

Invariants

This must always be a bounded interval; i.e. its endpoints must be finite.

samples: Vec<T>

The samples that are interpolated to extract values.

Invariants

This must always have a length of at least 2.

Implementations

impl<T> EvenCore<T>

pub fn new( domain: Interval, samples: impl IntoIterator<Item = T>, ) -> Result<Self, EvenCoreError>

Create a new EvenCore from the specified domain and samples. The samples are regarded to be evenly spaced within the given domain interval, so that the outermost samples form the boundary of that interval. An error is returned if there are not at least 2 samples or if the given domain is unbounded.

pub const fn domain(&self) -> Interval

The domain of the curve derived from this core.

pub fn sample_with<I>(&self, t: f32, interpolation: I) -> T

where T: Clone, I: Fn(&T, &T, f32) -> T,

Obtain a value from the held samples using the given interpolation to interpolate between adjacent samples.

The interpolation takes two values by reference together with a scalar parameter and produces an owned value. The expectation is that interpolation(&x, &y, 0.0) and interpolation(&x, &y, 1.0) are equivalent to x and y respectively.

pub fn sample_interp(&self, t: f32) -> InterpolationDatum<&T>

Given a time t, obtain a InterpolationDatum which governs how interpolation might recover a sample at time t. For example, when a Between value is returned, its contents can be used to interpolate between the two contained values with the given parameter. The other variants give additional context about where the value is relative to the family of samples.

pub fn sample_interp_timed(&self, t: f32) -> InterpolationDatum<(f32, &T)>

Like sample_interp, but the returned values include the sample times. This can be useful when sample interpolation is not scale-invariant.

Trait Implementations

impl<T: Clone> Clone for EvenCore<T>

fn clone(&self) -> EvenCore<T>

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<T: Debug> Debug for EvenCore<T>

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<'de, T> Deserialize<'de> for EvenCore<T>

where T: Deserialize<'de>,

fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl<T: PartialEq> PartialEq for EvenCore<T>

fn eq(&self, other: &EvenCore<T>) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl<T> Serialize for EvenCore<T>

where T: Serialize,

fn serialize<__S>(&self, __serializer: __S) -> Result<__S::Ok, __S::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.

impl<T: PartialEq> StructuralPartialEq for EvenCore<T>