ray-direction-classify

This is the first step in the paper by Eisemann et al. Fast Ray/Axis-Aligned Bounding Box Overlap Tests using Ray Slopes

install

npm install ray-direction-classify

use

var classifyRay = require('ray-direction-classify');
var rayDirection = [0, 1, 0];
 
var c = classifyRay(
  rayDirection[0],
  rayDirection[1],
  rayDirection[2]
);
 
console.log(c); // 4
console.log(c === classify.OPO); // true
 

ok, what is OPO?

constants

there are 25 classes of ray directions which are specified in a human readable format consisting of three character codes: P lus, M inus, and zer O

Ok, that might be a bit confusing so let's run through an example.

let's say that the ray in question has a direction of [1, -1, 0]. It's resulting 3-character code would be PMO

Here are a few more:

• [1, 0, 0] === classify.POO
• [-1, -1, -1] === classify.MMM
• [1, 0, 1] === classify.POP

The full list: MMM, MMP, MPM, MPP, PMM, PMP, PPM, PPP, POO, MOO, OPO, OMO, OOP, OOM, OMM, OMP, OPM, OPP, MOM, MOP, POM, POP, MMO, MPO, PMO, PPO

platforms

node, io.js, and evergreen browsers using browserify

license

MIT