RFC: RaycasterHelper

[gsimone]

Hey! 👋
I made a very simple raycaster helper for myself, was wondering if it isn't worth adding this along the other existing helpers.

https://user-images.githubusercontent.com/1862172/162688071-4993e811-2fe0-4b8a-99c6-99c38214d78e.mov

Try it here https://6tc01w.csb.app/

It displays:

• a segment going from origin to near + near to far
• the two near/far points
• optionally displays any hit via instances - this could just be points tbh
• optionally displays wether or not any hit exists

The style is halfway between @gkjohnson 's bvh ray visualizations and three's directional light helper

API is:

const raycaster = new Raycaster(origin, direction, near, far)
const helper = new RaycasterHelper( raycaster, 5 ) // raycaster + max number of hits to display

// in your loop
const hits = raycaster.intersectObjects( scene.children )
helper.hits = hits;

Some boring nuance:

• all the elements created by the helper have their raycast set as null, otherwise they'd always be hit by the ray they are visualizing 😓
• there's some inefficiency in the way lines are updated, but that should be easily fixed if it's worth doing
• all the components of the visualization are exposed as properties of the object, so they can be easily overridden, eg.

const helper = new RaycasterHelper( raycaster )
// make the hits red instead of white
helper.hitsVisualization.material.color = "#ff005b"

[mrdoob]

🤔

[mrdoob]

I'm also confused by these points:

🤔

[mrdoob]

Looks good though! Would be nice to put it in examples/jsm/helpers/.

[gsimone]

@mrdoob ops, that's silly me, I recorded this from a demo where I'm doing some experiments with layers, so there's a third capsule that doesn't show up in the camera layer lol

Also fixed the sandbox link, I forgot to remove some typescript when copypasting 😊

[mrdoob]

Ah I see...

Yeah, sounds good to me!

By the way, I just noticed that CapsuleGeometry's normals seem to have something wrong at the poles 🤔