Ray-aabb NPM | npm.io

ray-aabb

test if a ray intersects an aabb in 2d/3d space

Implemented via the techniques described in Fast Ray/Axis-Aligned Bounding Box Overlap Tests using Ray Slopes

install

npm install ray-aabb

use

var createRay = require('ray-aabb');

/*
                    +------+
                   /      /|
(-1, 1, 0) ---->  +------+ |
                  |      | +
                  |      |/
                  +------+
*/

var ray_origin = [-1, 1, 0];
var ray_direction = [1, 0, 0];
var ray = createRay(ray_origin, ray_direction);

var box = [
  [0, 0, 0],
  [2, 2, 2]
];

console.log(ray.intersects(box));
// outputs: true

// avoid allocating new memory by reusing rays
ray.update(ray_origin, [-1, 0, 0]);

console.log(ray.intersects(box));
// outputs: false

var normal = [0, 0, 0];
var d = ray.intersects(box, normal);
console.log(d);
// outputs: 1

console.log(normal);
// outputs: [ -1, 0, 0 ]

api surface

all vectors specified are arrays in the format: [x, y, z] with z being optional for 2d vectors

createRay(ray_origin, ray_direction)

parameters:

ray_origin - a vector defining the ray origin
ray_direction - a normalized vector defining the ray direction returns: a Ray instance

Ray#update(ray_origin, ray_direction)

Allows Ray instances to be reused by precomputing ray classification. The intention here is that you will be casting a ray against many aabbs

parameters: same as createRay

returns: this (e.g. ray.update(ro, rd).intersects(box)

Ray#intersects(aabb, normal) where aabb specifies the corners of the bounding box:

[[x1, y1, z1], [x2, y2, z2]]

and the optional normal argument is a 2d/3d vector (e.g., [0, 0]) that will be populated with the non-normalized normal of the corner/edge/face that the ray intersected with.

returns

if normal is not passed

true if intersection detected
false if no intersection

if normal is passed:

false if no intersection or a number denoting how far along the ray the collision occurred. You can use this number to compute the point of intersection. See the demos for example usage.