NewtonBodyAddImpulse in Newton 4

[Bird]

Hi Julio,

My project allows users to emit bodies into the scene. In older versions of Newton I used NewtonBodyAddImpulse. Could you please tell me how to accomplish the same in Newton 4?

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void NewtonCallbacks::OnApplyExternalForce (dInt32 threadIndex, dFloat32 timestep)
{

    RenderableNode node = weakNode.lock();
   
    ndBodyKinematic* const body = GetBody()->GetAsBodyKinematic();
    if (body && body->GetInvMass() > 0.0f)
    {
        dVector massMatrix (body->GetMassMatrix());
        dVector force (GetGravity().Scale (massMatrix.m_w));
        body->SetForce (force);
        body->SetTorque (dVector::m_zero);
    }

     if (node->description().emitDuration)
    {
        Eigen::Vector3f f = node->description().emitDirection * node->description().emitSpeed;
        Eigen::Vector3f p = node->getSpaceTime().worldTransform.translation();
        dVector impulse  = dVector(f.x(), f.y(), f.z(), 0.0f);
        dVector pos = dVector (p.x(), p.y(), p.z(), 0.0f);
        NewtonBodyAddImpulse (body, &impulse.m_x, &pos.m_x, timestep);

        --node->description().emitDuration;
    }
}

[Sweenie]

It was added a few days ago to the ndBodyKinematic class.

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   virtual void AddImpulse(const dVector& pointVeloc, const dVector& pointPosit, dFloat32 timestep);
   
virtual void ApplyImpulsePair(const dVector& linearImpulse, const dVector& angularImpulse, dFloat32 timestep);

   virtual void ApplyImpulsesAtPoint(dInt32 count, const dVector* const impulseArray, const dVector* const pointArray, dFloat32 timestep);

[Bird]

Thanks. I just saw that. Several of the demos are crashing in the latest version on github. Looks like it's happening on line 532 of ndSkeletonContainer.cpp. Do you know if this version stable enough to hook up to or should I wait ?

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#ifdef USE_ISLAND_SOLVER
   dAssert(0);
   m_isResting = equilibrium ? true : false;
#endif

[Sweenie]

Not sure. There is a lot of experimenting with the island free solver in the latest revisions so i'm not sure which one could be considered to be stable
I guess we have to wait for Julio to answer that.

[Bird]

I gave the latest github version a try and am hitting this issue when emitting new bodies

https://github.com/MADEAPPS/newton-dynamics/issues/258

[Julio Jerez]

yes I probable commit a work in progress than I should not, I will fix it this weekend.