Updated RigidBody to support rotation & angular momentum

Main thread, see last few posts:
www.garagegames.com/mg/forums/result.thread.php?qt=73905

I've updated RigidBody to properly support moments of inertia and angular momentum, meaning the rotational component of applied impulses is properly calculated.

The basic problem is that spheres seem to behave correctly, but boxes want to rest on their edges or a corner. Sometimes they will rest flat on a face (like you expect) but usually not. Boxes that aren't square are worse, tending to roll wildly and even clip through the terrain falling to infinity.

I'm posting my changes because I need a second opinion. I'm not a physics expert, so please let me know if you find a fix!


First, in T3DRigidComponent.cs replace the RotationScale property with this code:

[TorqueCloneIgnore]
        // we actually are cloning this, but the debug clone checker doesn't think we are
        public float RotationScale
        {
            get
            {
                return rotationScale;
            } // todo
            set
            {
                rotationScale = value;                
            } // just let us null it out
        }

        private float rotationScale = 0.0f;

        protected internal override void _PostRegister()
        {
            if (rotationScale == 0.0f)
            {
                _rigidBody.SetNullTensor();
            }
            else
            {
                //NOTE: kinda hacky right now, but works well enough
                if (this.CollisionBody != null && this.CollisionBody.CollisionShapes.Count > 0)
                {
                    if (this.CollisionBody.CollisionShapes[0] is CollisionSphereShape)
                    {
                        _rigidBody.SetObjectInertia();  //unit sphere
                    }
                    else
                    {
                        Box3F box = this.CollisionBody.Bounds;
                        Vector3 boxSize = box.Max - box.Min;
                        _rigidBody.SetObjectInertia(ref boxSize);
                    }
                }
                else
                {
                    _rigidBody.SetObjectInertia();
                }
            }

            base._PostRegister();
        }

Now download this zip file:

www.boneville.net/torque/rigid_torquex_patch.zip

It replaces RigidBody.cs and RigidState.cs


Now load up the FPS demo and select the Physics level. You'll see the issue with the boxes.