Merge pull request #585 from erwincoumans/master

btMultiBody joint friction/damping infrastructure

src/BulletDynamics/Featherstone/btMultiBody.cpp

@@ -1899,6 +1899,9 @@ const char*	btMultiBody::serialize(void* dataBuffer, class btSerializer* seriali
 				getLink(i).m_inertiaLocal.serialize(memPtr->m_linkInertia);
 				memPtr->m_linkMass = getLink(i).m_mass;
 				memPtr->m_parentIndex = getLink(i).m_parent;
+				memPtr->m_jointDamping = getLink(i).m_jointDamping;
+				memPtr->m_jointFriction = getLink(i).m_jointFriction;
+
 				getLink(i).m_eVector.serialize(memPtr->m_parentComToThisComOffset);
 				getLink(i).m_dVector.serialize(memPtr->m_thisPivotToThisComOffset);
 				getLink(i).m_zeroRotParentToThis.serialize(memPtr->m_zeroRotParentToThis);

src/BulletDynamics/Featherstone/btMultiBody.h

@@ -691,8 +691,9 @@ struct btMultiBodyLinkDoubleData
 	double					m_jointPos[7];
 	double					m_jointVel[6];
 	double					m_jointTorque[6];
-	
-	
+
+	double					m_jointDamping;
+	double					m_jointFriction;
 	
 };
 
@@ -721,7 +722,8 @@ struct btMultiBodyLinkFloatData
 	float					m_jointVel[6];
 	float					m_jointTorque[6];
 	int						m_posVarCount;
-	
+	float					m_jointDamping;
+	float					m_jointFriction;
 
 };
 

src/BulletDynamics/Featherstone/btMultiBodyLink.h

@@ -132,8 +132,10 @@ btVector3 m_appliedConstraintForce;    // In WORLD frame
 
 	const char* m_linkName;//m_linkName memory needs to be managed by the developer/user!
 	const char* m_jointName;//m_jointName memory needs to be managed by the developer/user!
+	btScalar m_jointDamping; //todo: implement this internally. It is unused for now, it is set by a URDF loader. User can apply manual damping.
+	btScalar m_jointFriction; //todo: implement this internally. It is unused for now, it is set by a URDF loader. User can apply manual friction using a velocity motor.
 
-    // ctor: set some sensible defaults
+	// ctor: set some sensible defaults
 	btMultibodyLink()
 		: 	m_mass(1),
 			m_parent(-1),
@@ -146,7 +148,9 @@ btVector3 m_appliedConstraintForce;    // In WORLD frame
 			m_jointType(btMultibodyLink::eInvalid),
 			m_jointFeedback(0),
 			m_linkName(0),
-			m_jointName(0)
+			m_jointName(0),
+			m_jointDamping(0),
+			m_jointFriction(0)
 	{
 		
 		m_inertiaLocal.setValue(1, 1, 1);