Module math 

FFI-safe mathematical types for the engine.

This module provides #[repr(C)] mathematical types that are safe to pass across FFI boundaries. These types wrap functionality from cgmath but guarantee a stable, predictable memory layout for use with C#, Python, and other language bindings.

Design Decision

We wrap cgmath rather than replacing it because:

1. Internal Operations: cgmath provides battle-tested matrix/vector operations (look_at, quaternion math, etc.) that would be error-prone to reimplement
2. FFI Safety: cgmath types like Vector3<f32> are newtypes over arrays and don’t guarantee a specific memory layout suitable for FFI
3. Type Safety: Our wrappers ensure compile-time FFI compatibility while maintaining ergonomic conversions for internal use

Usage

use goud_engine::core::math::{Vec3, Color};

// Create FFI-safe types
let position = Vec3::new(1.0, 2.0, 3.0);
let color = Color::RED;

// Convert to cgmath for internal math operations
let cgmath_vec: cgmath::Vector3<f32> = position.into();

// Convert back from cgmath results
let result = Vec3::from(cgmath_vec);

Structs

BezierEasing

Cubic Bezier easing with two control points.

Color

An RGBA color with FFI-safe memory layout.

Matrix3

A 3 x 3, column major matrix

Matrix4

A 4 x 4, column major matrix

Point3

A point in 3-dimensional space.

Quaternion

A quaternion in scalar/vector form.

Rect

A 2D rectangle with FFI-safe memory layout.

Vec2

A 2D vector with FFI-safe memory layout.

Vec3

A 3D vector with FFI-safe memory layout.

Vec4

A 4D vector with FFI-safe memory layout.

Enums

Easing

Enumeration of built-in easing types plus custom cubic Bezier.

Traits

Tweenable

A type that can be interpolated between two values.

Functions

ease_in

Quadratic ease-in (slow start).

ease_in_back

Ease-in with overshoot (back easing).

ease_in_out

Quadratic ease-in-out (slow start and end).

ease_out

Quadratic ease-out (slow end).

ease_out_bounce

Bounce ease-out.

linear

Linear easing (identity).

tween

Convenience function to tween a single f32 value with an easing function.

Type Aliases

EasingFn

Type alias for easing functions: maps normalized time t in [0, 1] to a curved value.