bvh-tree

A Bounding Volume Hierarchy data structure, for fast ray-mesh intersection

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Readme

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

```js 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

```js // 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