Bullet 2.81 Released: Rolling Friction, XML, iOS Neon

Erwin Coumans · **Posted:** Mon Oct 08, 2012 7:48 pm

The new Bullet 2.81 SDK is available for download: https://code.google.com/p/bullet/downloads/list
Some of the features of the new release are:

SIMD and Neon optimizations for iOS and Mac OSX, thanks to a contribution from Apple.
Rolling Friction using a constraint, thanks to Erin Catto for the idea. See Demos/RollingFrictionDemo/RollingFrictionDemo.cpp.
XML serialization. See Bullet/Demos/BulletXmlImportDemo for XML import and use the -dump_xml option in Bullet/Demos/SerializeDemo to convert from binary .bullet to XML. Note that the XML import is work-in-progress.
Gear constraint, thanks to Dimitris Papavasiliou for the idea. See Bullet/Demos/ConstraintDemo.
Improved continuous collision response, feeding speculative contacts to the constraint solver. See Bullet/Demos/CcdPhysicsDemo.
Improved premake4 build system including support for Mac OSX, Linux and iOS.
Refactoring of collision detection pipeline using stack allocation instead of modifying the collision object. This will allow better future multithreading optimizations.
New force/torque joint feedback, see btTypedConstraint::setJointFeedback
New work-in-progress Bullet Quickstart manual, with full LaTeX source. See Bullet/docs/BulletQuickstart.pdf

Although the focus is on the Bullet 3.x release, we will still work on fixing outstanding issues for Bullet 2.x.

Thanks everyone for the contributions and feedback!
Enjoy,
Erwin

mobeen · **Joined:** Thu May 05, 2011 11:47 am **Posts:** 61

Hi Erwin,
Thanks for the latest update. Just one thing, I am trying to run my old demo of a box falling on a plane. I get the correct result in the previous releases. Now the box does no bounce much and directly comes to rest. Are there any new parameters that I need to set?

here is the relevant code to setup the rigid bodies i.e. the box and the ground plane

Code:

void InitializeBullet() {
   broadphase            = new btDbvtBroadphase();
   collisionConfiguration   = new btDefaultCollisionConfiguration();
   dispatcher            = new btCollisionDispatcher(collisionConfiguration);
   solver               = new btSequentialImpulseConstraintSolver;
   dynamicsWorld         = new btDiscreteDynamicsWorld(dispatcher,broadphase,solver,collisionConfiguration);

   dynamicsWorld->setGravity(btVector3(0,-9.8f,0));

   groundShape = new btStaticPlaneShape(btVector3(0,1,0),0);
   fallShape   = new btBoxShape(btVector3(0.5f, 0.5f, 0.5f)); //btSphereShape(1);

   btDefaultMotionState* groundMotionState = new btDefaultMotionState(btTransform(btQuaternion(0,0,0,1),btVector3(0,0,0)));
   btRigidBody::btRigidBodyConstructionInfo groundRigidBodyCI(0,groundMotionState,groundShape,btVector3(0,0,0));
   groundRigidBody = new btRigidBody(groundRigidBodyCI);
   dynamicsWorld->addRigidBody(groundRigidBody);

   btDefaultMotionState* fallMotionState = new btDefaultMotionState(btTransform(btQuaternion(0,0,0,1),btVector3(0,10,0)));
   btScalar mass = 10;
   btVector3 fallInertia(0,0,0);
   
   fallShape->calculateLocalInertia(mass,fallInertia);
   btRigidBody::btRigidBodyConstructionInfo fallRigidBodyCI(mass,fallMotionState,fallShape,fallInertia);
   box = new btRigidBody(fallRigidBodyCI);   
   dynamicsWorld->addRigidBody(box);
}

Thanks,
Mobeen

STTrife · **Joined:** Tue May 01, 2012 10:42 am **Posts:** 40

Thanks for a great release!!!

Can you explain a little about the speculative contacts??

Thanks!

henron · **Joined:** Mon Feb 25, 2013 6:30 pm **Posts:** 1

Quote:

Although the focus is on the Bullet 3.x release, we will still work on fixing outstanding issues for Bullet 2.x.
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"Improved premake4 build system including support for Mac OSX, Linux and iOS."
I was just wondering I just ordered an iPad will this be compatible?

jokooon · **Joined:** Wed Apr 20, 2011 12:42 pm **Posts:** 10

Code:

    struct char_cbk: public btCollisionWorld :: ContactResultCallback
    {
       virtual btScalar addSingleResult(btManifoldPoint &cp, const btCollisionObject *colObj0,
         int partId0, int index0, const btCollisionObject *colObj1, int partId1, int index1)
       {
         if(colObj1==colobj_ground)
         {
            strs["dudu"]=TO_STR(BtOgre::Convert::toOgre(cp.m_localPointB));
            vecs["dudu"]=BtOgre::Convert::toOgre(cp.m_localPointB);

         }
         //strs["partId0"]=TO_STR(partId0);
         //strs["index0"]=TO_STR(index0);
         //strs["partId1"]=TO_STR(partId1);
         //strs["index1"]=TO_STR(index1);

          return 0.0f;
       }
    };

   char_cbk ch_cbk2;

With MSVC10 I get the error

Code:

Error   1   error C2259: 'physics::char_cbk' : cannot instantiate abstract class

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Bullet 2.81 Released: Rolling Friction, XML, iOS Neon

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