Crate bvh 

A crate which exports rays, axis-aligned bounding boxes, and binary bounding volume hierarchies.

About

This crate can be used for applications which contain intersection computations of rays with primitives. For this purpose a binary tree Bvh (Bounding Volume Hierarchy) is of great use if the scene which the ray traverses contains a huge number of primitives. With a Bvh the intersection test complexity is reduced from O(n) to O(log2(n)) at the cost of building the Bvh once in advance. This technique is especially useful in ray/path tracers. For use in a shader this module also exports a flattening procedure, which allows for iterative traversal of the Bvh.

Note

If you are concerned about performance, you should make sure to use RUSTFLAGS='-C target-cpu=native' for the best possible speedup.

Example

use bvh::aabb::{Aabb, Bounded};
use bvh::bounding_hierarchy::{BHShape, BoundingHierarchy};
use bvh::bvh::Bvh;
use nalgebra::{Point3, Vector3};
use bvh::ray::Ray;

let origin = Point3::new(0.0,0.0,0.0);
let direction = Vector3::new(1.0,0.0,0.0);
let ray = Ray::new(origin, direction);

struct Sphere {
    position: Point3<f32>,
    radius: f32,
    node_index: usize,
}

impl Bounded<f32,3> for Sphere {
    fn aabb(&self) -> Aabb<f32,3> {
        let half_size = Vector3::new(self.radius, self.radius, self.radius);
        let min = self.position - half_size;
        let max = self.position + half_size;
        Aabb::with_bounds(min, max)
    }
}

impl BHShape<f32,3> for Sphere {
    fn set_bh_node_index(&mut self, index: usize) {
        self.node_index = index;
    }

    fn bh_node_index(&self) -> usize {
        self.node_index
    }
}

let mut spheres = Vec::new();
for i in 0..1000u32 {
    let position = Point3::new(i as f32, i as f32, i as f32);
    let radius = (i % 10) as f32 + 1.0;
    spheres.push(Sphere {
        position: position,
        radius: radius,
        node_index: 0,
    });
}

let bvh = Bvh::build_par(&mut spheres);
let hit_sphere_aabbs = bvh.traverse(&ray, &spheres);

Features

• std (default enabled) - enables the standard library; disable for no_std targets
• serde (default disabled) - adds Serialize and Deserialize implementations for some types
• rayon (default enabled) - parallelize building of the BVH (via rayon)
• simd (default enabled) - enables explicit SIMD kernels (via wide) for ray-AABB intersection

Modules

aabb

Axis Aligned Bounding Boxes.

ball

Balls, including circles and spheres.

bounding_hierarchy

This module defines the BoundingHierarchy trait.

bvh

This module defines a Bvh.

flat_bvh

This module exports methods to flatten the Bvh into a FlatBvh and traverse it iteratively.

point_query

Contains the PointDistance trait used for querying the distance to a point to a bvh.

ray

This module holds the Ray definition, and RayIntersection functions.