Crate tinybvh_rs 

tinybvh-rs

Opinionated rust wrapper for tinybvh.

Features

• BVH, MBVH BVH8_CPU, CWBVH
• Intersection

Unimplemented features:

• Optimize via Verbose
• Loading/saving from/to disk

For more information about each layout, have a look at the original tinybvh library.

Examples

BVH Wald

use tinybvh_rs::{bvh, Intersector, Ray};

let primitives = vec![
    [-2.0, 1.0, -1.0, 0.0],    //
    [-1.0, 1.0, -1.0, 0.0],    // Left triangle
    [-2.0, 0.0, -1.0, 0.0],    //

    [2.0, 1.0, -1.0, 0.0],     //
    [2.0, 0.0, -1.0, 0.0],     // Right triangle
    [1.0, 0.0, -1.0, 0.0],     //
];

let bvh = bvh::BVH::new(primitives.as_slice().into()).unwrap();

// No intersection, ray pass between the primitives
let mut ray = Ray::new([0.0, 0.0, 0.0], [0.0, 0.0, -1.0]);
bvh.intersect(&mut ray);
println!("Hit distance: {}", ray.hit.t); // 1e30

// Intersects left primitive
let mut ray = Ray::new([-1.5, 0.5, 0.0], [0.0, 0.0, -1.0]);
bvh.intersect(&mut ray);
println!("Hit distance & primitive: {} / {}", ray.hit.t, ray.hit.prim); // 1.0 / 0

// Intersects right primitive
let mut ray = Ray::new([1.5, 0.45, 0.0], [0.0, 0.0, -1.0]);
bvh.intersect(&mut ray);
println!("Hit distance & primitive: {} / {}", ray.hit.t, ray.hit.prim); // 1.0 / 1

BVH8_CPU

let mut bvh = bvh::BVH::new(primitives.as_slice().into()).unwrap();
bvh.split_leaves(4); // Required or BVH8_CPU will return an error
let mbvh = mbvh::BVH::new(&bvh);
let bvh8 = bvh8_cpu::BVH::new(&mbvh).unwrap();
bvh8.intersect(&mut ray);

CWBVH

let mut bvh = bvh::BVH::new(primitives.as_slice().into()).unwrap();
bvh.split_leaves(3); // Required or the CWBVH will return an error

let mbvh = mbvh::BVH::new(&bvh);
let cwbvh = cwbvh::BVH::new(&mbvh).unwrap();

println!("{}", cwbvh.nodes());
println!("{}", cwbvh.primitives());

Strided

If the vertices position are strided (located in a Vertex struct for instance), you can enable the strided feature and use:

use tinybvh_rs::{Intersector, Ray};

#[repr(C)]
#[derive(Clone, Copy, bytemuck::Pod, bytemuck::Zeroable)]
struct Vertex {
    position: [f32; 4],
    normal: [f32; 3],
}

let vertices = [
    Vertex {
        position: [-1.0, 1.0, -1.0, 0.0],
        normal: [0.0, 0.0, 1.0]
    },
    Vertex {
        position: [-0.5, 1.0, -1.0, 0.0],
        normal: [0.0, 0.0, 1.0]
    },
    Vertex {
        position: [-1.0, 0.0, -1.0, 0.0],
        normal: [0.0, 0.0, 1.0]
    },
];
let positions = pas::slice_attr!(vertices, [0].position);
let bvh = bvh::BVH::new(positions);

Safe rust wrapper for the C++ tinybvh library.

Notes

BVH layouts are splitted into:

• BVHData: read-only operations
  • Read nodes, and primitives slice
  • SAH cost, etc…
• BVH: Read-write operations
  • Building, converting, refitting, etc…
  • Implements Deref to access BVHData directly

This is a pattern used throughout this crate to ensure maximum safety, since the tinybvh library stores reference to primitives and original BVH upon build and conversion.

BVH layouts that manage their own primitives have no lifetime constraint. This is for instance the case for cwbvh::BVH and bvh8_cpu::BVH.

Modules

bvh

“Wald” BVH layout

bvh8_cpu

8-way BVH

cwbvh

CWBVH GPU-friendly layout

mbvh

Structs

Intersection

Intersection data.

Ray

Ray data.

Enums

Error

Error type for Wald BVH operations.

Constants

INFINITE

Infinite value used for intersection.

Traits

Intersector

Intersector for BVH and nodes intersection.

Type Aliases

Positions

Alias for a strided slice of positions.