rs-math3d

rs-math3d is a no_std-friendly 2D/3D math library focused on computer graphics and geometry. It provides vectors, matrices, quaternions, transforms, and common geometric primitives with utility traits for intersection and distance queries.

Features

Vector math (2D/3D/4D), dot/cross products, swizzles, and float-only normalization helpers
Matrix math (2x2/3x3/4x4), determinants, and float-only inverses and affine fast-paths
Quaternions and transforms for floating-point rotations and projections
Geometric primitives: rays, planes, triangles, boxes, spheres, line segments
Query traits for intersection and distance computations
no_std support with an optional std feature

Integer vectors, boxes, rectangles, and matrix arithmetic are supported for discrete geometry and storage. Operations that require fractional results, such as normalization, inversion, quaternions, transforms, rays, planes, and geometric queries, are restricted to f32/f64.

Usage

Add to Cargo.toml:

[dependencies]
rs-math3d = { version = "0.12.0", default-features = false }

Select one math backend:

rs-math3d = { version = "0.12.0", default-features = false, features = ["std"] }
rs-math3d = { version = "0.12.0", default-features = false, features = ["libm"] }
rs-math3d = { version = "0.12.0", default-features = false, features = ["system-libm"] }

When no math backend feature is selected, normal library builds fall back to system-libm. Test builds without an explicit backend use std. If more than one backend feature is enabled, precedence is std, then libm, then system-libm.

Behavior Notes

Ray/Tri3 intersection is a true ray query: hits behind the ray origin are rejected. Use the corresponding Line/Tri3 intersection when you want the infinite-line result.
ParametricPlane::project solves the 2x2 Gram system of the plane axes, so projection works for non-orthogonal axes as well as orthogonal ones.
Sphere3::new canonicalizes the radius with abs(radius).
Quat::mat3 and Quat::mat4 normalize the quaternion before converting it to a matrix.
Plane::from_quad and Plane::try_from_quad use a diagonal-derived representative plane. They do not validate that the four vertices are coplanar.
transforms::lookat assumes eye != dest and an up vector that is not parallel to the view direction. Violating those preconditions yields non-finite output.
Tri3::barycentric_coordinates assumes a non-degenerate triangle. Degenerate triangles produce non-finite coordinates.

Example

use rs_math3d::vector::Vector3;
use rs_math3d::transforms;
use rs_math3d::EPS_F32;
use core::f32::consts::PI;

fn main() {
    let axis = Vector3::new(0.0f32, 1.0, 0.0);
    let rot = transforms::rotation_from_axis_angle(&axis, PI / 4.0, EPS_F32)
        .expect("axis length too small");
    let trans = transforms::translate(Vector3::new(1.0f32, 2.0, 3.0));

    let m = trans * rot;
    let p = Vector3::new(1.0f32, 0.0, 0.0);
    let out = m * p;
    let _ = out;
}

Modules