bvh-tree

A Bounding Volume Hierarchy data structure written in javascript, for spatial indexing of large triangle meshes. Enables fast intersection of rays with a triangle mesh.

Demo

ray-mesh intersection

Usage

Construct a BVH from a list of triangles

var triangle0 = [
  {x: 0.0, y: 0.0, z: 0.0},
  {x: 1000.0, y: 0.0, z: 0.0},
  {x:1000.0, y:1000.0, z:0.0}
];

var triangle1 = [
  {x: 0.0, y: 0.0, z: 0.0},
  {x: 2000.0, y: 0.0, z: 0.0},
  {x:2000.0, y:1000.0, z:0.0}
];

// the maximum number of triangles that can fit in a node before splitting it.
var maxTrianglesPerNode = 7; 

var bvh = new bvhtree.BVH([triangle0, triangle1], maxTrianglesPerNode);

Intersect a ray with the BVH

// origin point of the ray
var rayOrigin = {x: 1500.0, y: 3.0, z:1000};

// direction of the ray. should be normalized to unit length
var rayDirection = {x: 0, y:0, z:-1};

// if 'true', only intersections with front-faces of the mesh will be performed
var backfaceCulling = true;

var intersectionResult = bvh.intersectRay(rayOrigin, rayDirection, backfaceCulling);

intersectsRay() returns an array of intersection result objects, one for each triangle that intersected the ray. Each object contains the following properties:

• triangle the triangle which the ray intersected
• triangleIndex the position of the interescting triangle in the input triangle array provided to the BVH constructor.
• intersectionPoint the interesection point of the ray on the triangle.

License

Copyright (c) 2015 Ben Raziel. MIT License