implement basic picking

[pixelflinger]

Discussed in #3827

^{Originally posted by ThomasGorisse April 20, 2021}
Hi Filament Team,

I'm currently working on the Collision part of an upcoming ARCore/Filament repo.

Since there is not yet any raycasting implementation available on Filament from what I saw, I have 2 choices:

1. Use the ARCore hitTest() from Frame based on the Scene Anchors Entitys which is quite high level since it can take a MotionEvent or Ray parameter and return the corresponding real world Pose that I can use to detect collision with the FilamentAsset bounding box.
   BUT this involve excluding the non AR (Filament only) usage in the framework.
2. Implement the Collision system from scratch inside the framework and use the ARCore HitTest when the renderable is anchored in the real world.

My questions:

1. Is there any plan to implement raycasting/collision directly inside Filament ?
2. Do you have any link/infos on already implemented raycasting/collision systems ?

Thanks

[pixelflinger]

We won't implement a sophisticated ray-casting/collision system, however, basic picking would be very useful.

[pixelflinger]

fixed in #4657