2ea0061018
# Objective - Make cubic splines more flexible and more performant - Remove the existing spline implementation that is generic over many degrees - This is a potential performance footgun and adds type complexity for negligible gain. - Add implementations of: - Bezier splines - Cardinal splines (inc. Catmull-Rom) - B-Splines - Hermite splines https://user-images.githubusercontent.com/2632925/221780519-495d1b20-ab46-45b4-92a3-32c46da66034.mp4 https://user-images.githubusercontent.com/2632925/221780524-2b154016-699f-404f-9c18-02092f589b04.mp4 https://user-images.githubusercontent.com/2632925/221780525-f934f99d-9ad4-4999-bae2-75d675f5644f.mp4 ## Solution - Implements the concept that splines are curve generators (e.g. https://youtu.be/jvPPXbo87ds?t=3488) via the `CubicGenerator` trait. - Common splines are bespoke data types that implement this trait. This gives us flexibility to add custom spline-specific methods on these types, while ultimately all generating a `CubicCurve`. - All splines generate `CubicCurve`s, which are a chain of precomputed polynomial coefficients. This means that all splines have the same evaluation cost, as the calculations for determining position, velocity, and acceleration are all identical. In addition, `CubicCurve`s are simply a list of `CubicSegment`s, which are evaluated from t=0 to t=1. This also means cubic splines of different type can be chained together, as ultimately they all are simply a collection of `CubicSegment`s. - Because easing is an operation on a singe segment of a Bezier curve, we can simply implement easing on `Beziers` that use the `Vec2` type for points. Higher level crates such as `bevy_ui` can wrap this in a more ergonomic interface as needed. ### Performance Measured on a desktop i5 8600K (6-year-old CPU): - easing: 2.7x faster (19ns) - cubic vec2 position sample: 1.5x faster (1.8ns) - cubic vec3 position sample: 1.5x faster (2.6ns) - cubic vec3a position sample: 1.9x faster (1.4ns) On a laptop i7 11800H: - easing: 16ns - cubic vec2 position sample: 1.6ns - cubic vec3 position sample: 2.3ns - cubic vec3a position sample: 1.2ns --- ## Changelog - Added a generic cubic curve trait, and implementation for Cardinal splines (including Catmull-Rom), B-Splines, Beziers, and Hermite Splines. 2D cubic curve segments also implement easing functionality for animation.
27 lines
701 B
Rust
27 lines
701 B
Rust
//! Provides math types and functionality for the Bevy game engine.
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//!
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//! The commonly used types are vectors like [`Vec2`] and [`Vec3`],
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//! matrices like [`Mat2`], [`Mat3`] and [`Mat4`] and orientation representations
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//! like [`Quat`].
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#![warn(missing_docs)]
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pub mod cubic_splines;
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mod ray;
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mod rect;
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pub use ray::Ray;
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pub use rect::Rect;
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/// The `bevy_math` prelude.
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pub mod prelude {
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#[doc(hidden)]
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pub use crate::{
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cubic_splines::{BSpline, Bezier, CardinalSpline, CubicGenerator, CubicSegment, Hermite},
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BVec2, BVec3, BVec4, EulerRot, IVec2, IVec3, IVec4, Mat2, Mat3, Mat4, Quat, Ray, Rect,
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UVec2, UVec3, UVec4, Vec2, Vec3, Vec4,
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};
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}
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pub use glam::*;
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