[Bullet] Adding a high amount of physics bodies is significantly slower with Bullet compared to GodotPhysics

[Kay-Eth]

Godot version: Godot 3.1.1
OS/device including version: Windows 10

Issue description:
When I'm adding 100,000 StaticBodies to the scene, each with CollisionShape, and set on each CollisionShape.disable to true, I have 1 FPS. But when I change to GodotPhysics, I have stable 60 FPS.
Event better, if I use GodotPhysics and set on each CollisionShape.disable to false, I still have 60 FPS (and when using Bullet - 1 FPS).

Steps to reproduce:
Do what I have wrote in Issue description

Here is a little sample project. Camera is not needed
Link

[codecustard]

Sample project link is broken.

[Kay-Eth]

Weird.... Just select it, copy and paste
[Edit] It works now ;)

[NuclearPhoenixx]

Still broken for me. Just drag and drop it here on Github. You don't need an external host.

[burstina]

LINK to project is still broken

I was able to reproduce the issue:
Just create an empty GridMap, associate to a non-empty MeshLib, create a script who starts a thread that populate a 1000x1000x1 square.
It is important to use the thread for we can look at slowness during runtime.

Run using Bullet, then run using GodotPhysics.

[AndreaCatania]

Do you have areas in your scene?

[Kay-Eth]

No, there is not a single one area

[Hromon]

And Bullet crash app if use multi-thread.

Thread thread = new Tread(Gen);

Gen()
{
CollisionShape.Shape = ArrayMesh.CreateTrimeshShape()
}

Bullet - crash, GodotPhysics - don't crash...

[AndreaCatania]

The Bullet integration were 2 times slower than the Godot Physics, when adding bodies. Here: #39726 I've improved the timing drastically, please test it and let me know.

Thanks for the report!

[AndreaCatania]

By the way, Please don't add collision body from a thread. It's not safe to do.

Consider adding it in batch each frame. (This is true for Godot physics and Bullet physics).

[madmiraal]

Reopening, because #39726 was reverted in #42639.

[slapin]

This is kind of clickbait bug, the problem is speed of adding bodies, not physics simulation here.

[akien-mga]

This is kind of clickbait bug, the problem is speed of adding bodies, not physics simulation here.

Good point, I edited the title to be clearer.