I'm making a physics extension/Help with 3D physics extension?

[Brackets-Coder]

video.mp4

I'm making a physics extension. It's not near done yet; this is a proof of concept, but it still kinda works.

it uses cannon.js for physics calculations but I couldn't use ammo.js because it relies on wasm and isn't native javascript...

So even though cannon is kinda old it still works.

Goals for this extension:

• Work well with any 3D renderer
• Great performance
• Support Spheres, planes, boxes, cylinders, convex hulls, and triangle meshes (just spheres and boxes as of now)
• Discrete collision detection (basically <is [body1] touching [body2]?> and <get all bodies touching [body]>)
• Constraint support
  • Point to point
  • Distance
  • Hinge
  • Lock
  • ConeTwist
• Enable/disable collision response for bodies (still detect collision but don't react to forces)

basically it's supposed to support everything cannon.js supports.

Don't know why the video is starting at the middle instead of the beginning

[CubesterYT]

This is amazing! The things you do are awesome, it's great having you a part of this community!

(If you have Discord, you should definitely join our community there!)

[Brackets-Coder]

Thank you. My favorite form of development by far is making websites and Turbowarp extensions, so I try do what I can to learn more and help more.

P.S. I don't have Discord and haven't planned on getting it just because of people on the internet being people on the internet (if you know what I mean)
My main communities will continue to be Scratch and GitHub if that's fine with you.

[CubesterYT]

Honestly, our community is a great place compared to most places (a lot more mature and trustworthy), but I respect your stance!

[Brackets-Coder]

@CubesterYT I don't think this is how physics is supposed to work...

Do you have any idea why this is happening? My guess is it has something to do with quaternion to XYZ degree Euler conversion or something related to gimbal lock or something like that but I thought I fixed that.
It's probably not the library because other renderer implementations work.

It might be a better question for @Xeltalliv because of Simple3D integration and things

video.mp4

[CubesterYT]

This is definitely a question for @Xeltalliv

[Xeltalliv]

Wrong rotation order probably? Possibly wrong signs on rotations as well.

Also, the physics engine probably has the model space to world space matrices already somewhere inside, so you should be able to feed those directly into Simple3D using "start with saved in [list v] at (1)" block, instead of dealing with conversions between different rotation formats.

[Xeltalliv]

Also, from what it seems, in your extension you can only have 1 collider per rigidbody, which is a very big limitation. For example, my custom physics engine allows for multiple colliders per rigidbody, which is how tables and chairs in this scene are possible:

[Brackets-Coder]

@Xeltalliv It's definitely due to some inconsistency of the transformations between your renderer/my engine/my implementation of physics. I considered the possibility of wrong rotation order/sign, but there's a script that turns the quaternions into XYZ degree Eulers. I think that's the main issue, there could also be some gimbal lock things going on because I've seen evidence for that in other examples. Cannon.js actually has quaternion to euler functions, but attempting to pass in the "XYZ" argument to re-order the Euler returns an error that "the order 'XYZ' isn't supported yet", so I had to write some custom conversion scripts that are probably the main issue. Cannon.js is an old(er) library but it's the only native JS solution that's still somewhat prevalent. Ammo requires WebAssembly so it can't be a TW extension

Also Cannon does support multiple shapes/colliders per body but I haven't implemented blocks that add new shapes to existing bodies yet

[Brackets-Coder]

This gets even weirder when I use an infinite plane instead of a finite, thin box

video.mp4

[Brackets-Coder]

I think I'm just going to re-write this whole extension from scratch again. Of course, I'll save a backup of the current version but Cannon.js just has too many limitations and the main thing holding me back from using Ammo.js was the fact that I thought it required WebAssembly but I think I figured out how to minify it and use the native JS version so I'll try that and see if it's any better

[Brackets-Coder]

@CubesterYT I'm having some issues trying to get Ammo.js to work. It works like this:

But not like this:

Of course, I know I'm supposed to put the proper ESLint comments around any minified libraries and they have to be self-contained within the extension, but something in Ammo just won't let it happen unless it's in the global scope. Any idea how I can fix this? I tried assigning it to a script tag and injecting it to the <head> but that didn't work and assigning based on window.Ammo = didn't work either.

[CubesterYT]

Try swapping var for const

[Brackets-Coder]

still doesn't work, it returns Uncaught TypeError: Cannot set properties of undefined (setting 'Ammo') at line 27 when trying to initialize Ammo() unless the entire library is outside the extension's scope for some reason