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BVH (Bounding Volume Hierarchy)

A Bounding Volume Hierarchy (BVH) is a tree-based spatial partitioning structure where each node is enclosed by a bounding volume (AABB in this implementation). BVHs are highly efficient for raycasting and spatial queries, especially for dynamic or static scenes where objects are distributed non-uniformly.

Array Layout (Internal)​

[ aabb, left, right, data ]

  • aabb: The Box3 representing the boundaries of this node and all its children.
  • left: The left child BVH node (or undefined if leaf).
  • right: The right child BVH node (or undefined if leaf).
  • data: Array of objects stored in this node (only if leaf).

Creation and Building​

// 1. Prepare your objects and a function to get their AABB
var objects = [obj1, obj2, obj3];
var get_aabb = function(obj) {
    return obj.aabb; // Should return a Box3 array [minX, minY, minZ, maxX, maxY, maxZ]
};

// 2. Build the BVH
var root = bvh_build(objects, get_aabb);

Function Reference​

Base Operations​

FunctionDescription
bvh_create()Constructs a new empty BVH node.
bvh_build(objects, get_aabb_fn)Recursively builds a BVH from an array of objects.

Querying​

These functions retrieve a list of objects that might intersect with the given primitive.

bvh_query_box(node, box, results)​

Queries the BVH for objects whose AABB intersects the given box.

bvh_query_sphere(node, sphere, results)​

Queries the BVH for objects whose AABB intersects the given sphere.

bvh_query_frustum(node, frustum, results)​

Queries the BVH for objects whose AABB intersects the given frustum.

bvh_query_ray(node, ray, results)​

Queries the BVH for objects whose AABB intersects the given ray.

bvh_intersect_ray(node, ray)​

Finds the closest object intersection in the BVH. Returns a struct with {object, distance} or undefined.