Passing scene.meshes to GPUPicker.setPickingList will clear them when GPUPicker.dispose

Bugs
1

Hi everyone,

Not sure if this counts as a bug per se, but it does lead to one:

Do not pass scene.meshes to GPUPicker.setPickingList. Otherwise your meshes will be gone when you dispose the picker.

Workaround is to pass a copy of the scene.meshes array (e.g. scene.meshes.filter(()=>true)); See playground.

Best wishes
Joe

2

That’s an interesting catch :slight_smile:

We try not to make copies of passed resources ourselves. We expect the user to know what data is being passed. However, this probably should be documented, either in the dispose function or the setPickingList - the array passed will be cleared.
Want to submit a PR for the docs?

Oh, BTW - the simplest way to create a copy is [...scene.meshes]. This doesn’t iterate the entire array and technically creates a copy

3

Ok, on my todo list.

1 Like
4

Quick benchmark here:

result on firefox
result on firefox883Ă—614 20 KB

result on chrome
result on chrome635Ă—622 20.8 KB

Let’s recommand slice for better performance, and browser compatibility.

5

Tested on how many computer settings, OSs, browsers, browser versions? I would not recommend a specifc way to clone. This is user responsibility. The important info is that a passed in reference is changed.

6

Hello!

A PR was proposed here to fix I believe the same issue:

@Joe_Kerr

7

Just clone it yourself :sunglasses:

If Babylon clones it, there is only one possible outcome (-> clone). If Babylon does not, there is two possible outcomes (-> not clone, clone).

As a possible (non-tested) alternative that preserve performance, setPickingList could Object.freeze(list). That would at least more strongly communicate and actually enforce to some extent** that the GPUPicker takes ownership of the array. **extent referes to what Object.freeze actually freezes. But again. I would just clone it myself.

2 Likes
8

Yep. This is what I think as well :slight_smile:

We can have all kinds of smart solutions for this, but eventually you need to know that the array passed will be cleared. Now decide which array you are passing :slight_smile:

1 Like