There's no way to create joints (constraints) in the current API.

[bryanedds]

Maybe I'm missing something obvious, but I don't see a way to actually create any instances of a joint like DistanceConstraint or DistanceConstraintSettings. All of the joint constructors are non-public and inaccessible.

Assuming this can't get fixed very soon in the wrapper, can someone advise me on how to perhaps create one via reflection? I just need to know how to pass the required nint handle into the ctor when calling the constructor's invoke.

Thanks!

[amerkoleci]

Hi,
Thanks for bringing attention to those points, I'll fix them soon, hopefully tomorrow or within some days.

Thanks!

[bryanedds]

Awesome!

I was thinking perhaps it might just have been a minor oversight :)

Thank you kindly!

[amerkoleci]

Hi,
Constraints has been improved a lot, grab the new 2.12.1 and tell me if there is something missing.

Cheers,
Amer

[bryanedds]

Looks like I can access the constructors fine, now! However, I'm noticing that there might not be any way to access BodyLockMultiRead or BodyLockMultiWrite when creating constraints -

                    | AngleJoint hingeJoint ->
                        let constraintSettings = new HingeConstraintSettings ()
                        constraintSettings.Point1 <- hingeJoint.Anchor
                        constraintSettings.Point2 <- hingeJoint.Anchor2
                        let mutable bodyLockWrite = Unchecked.defaultof<_>
                        let mutable body2LockWrite = Unchecked.defaultof<_>
                        try physicsEngine.PhysicsContext.BodyLockInterface.LockWrite (&bodyID, &bodyLockWrite) // NOTE: assuming that jolt needs write capabilities for these.
                            physicsEngine.PhysicsContext.BodyLockInterface.LockWrite (&body2ID, &body2LockWrite) // TODO: P0: send support request to JoltPhysicsSharp maintainer to expose BodyLockMultiWrite so that we don't get a deadlock here if accessing from another thread!
                            let body = bodyLockWrite.Body
                            let body2 = body2LockWrite.Body
                            let constrain = constraintSettings.CreateConstraint (&body, &body2)
                            constrain.Enabled <- bodyJointProperties.BodyJointEnabled
                            Some constrain
                        finally
                            physicsEngine.PhysicsContext.BodyLockInterface.UnlockWrite &bodyLockWrite
                            physicsEngine.PhysicsContext.BodyLockInterface.UnlockWrite &body2LockWrite

This code could cause a deadlock according to https://github.com/jrouwe/JoltPhysics/blob/master/Docs/Architecture.md#multithreaded-access -

You cannot use BodyLockRead to lock multiple bodies (if two threads lock the same bodies in opposite order you'll get a deadlock). Use [BodyLockMultiRead](@ref BodyLockMultiRead) or [BodyLockMultiWrite](@ref BodyLockMultiWrite) to lock them in a consistent order.

I'm guessing the issue is that the BodyLockMultiRead and BodyLockMultiWrite types haven't been exposed by the wrapper yet?

[amerkoleci]

Hi,
I've just added multi lock read/write support, grab the 2.12.2 and tell me if it works?

Thanks

[bryanedds]

I've integrated the API and gotten everything to compile and work without actually exercising the deadlock prevention behavior. The actual testing of the additional MT semantics of multi-locking behavior won't taken place on my end since I just needed the construct to make sure I don't get deadlocking in some speculative future (IE, as a sanitation best practice).

Since I've not done the deep testing you might be wanting, I'm leaving closing the issue to your discretion.

[amerkoleci]

Hi,
Lets leave it open, when you'll be able to do deep testing reach out.

Thanks.
Amer