Add API to reset lateral friction coefficient.

examples/SharedMemory/PhysicsClientC_API.cpp

@@ -1240,6 +1240,17 @@ int b3ResetDynamicInfoSetMass(b3SharedMemoryCommandHandle commandHandle, int bod
 	return 0;
 }
 
+int b3ResetDynamicInfoSetLateralFriction(b3SharedMemoryCommandHandle commandHandle, int bodyUniqueId, int linkIndex, double lateralFriction)
+{
+	struct SharedMemoryCommand* command = (struct SharedMemoryCommand*) commandHandle;
+	b3Assert(command->m_type == CMD_RESET_DYNAMIC_INFO);
+	command->m_resetDynamicInfoArgs.m_bodyUniqueId = bodyUniqueId;
+	command->m_resetDynamicInfoArgs.m_linkIndex = linkIndex;
+	command->m_resetDynamicInfoArgs.m_lateralFriction = lateralFriction;
+	command->m_updateFlags |= RESET_DYNAMIC_INFO_SET_LATERAL_FRICTION;
+	return 0;
+}
+
 b3SharedMemoryCommandHandle b3InitCreateUserConstraintCommand(b3PhysicsClientHandle physClient, int parentBodyIndex, int parentJointIndex, int childBodyIndex, int childJointIndex, struct b3JointInfo* info)
 {
     PhysicsClient* cl = (PhysicsClient* ) physClient;

examples/SharedMemory/PhysicsClientC_API.h

@@ -80,6 +80,7 @@ int b3GetDynamicInfo(b3PhysicsClientHandle physClient, int bodyUniqueId, int lin
 	
 b3SharedMemoryCommandHandle b3InitResetDynamicInfo(b3PhysicsClientHandle physClient);
 int b3ResetDynamicInfoSetMass(b3SharedMemoryCommandHandle commandHandle, int bodyUniqueId, int linkIndex, double mass);
+int b3ResetDynamicInfoSetLateralFriction(b3SharedMemoryCommandHandle commandHandle, int bodyUniqueId, int linkIndex, double lateralFriction);
     
 b3SharedMemoryCommandHandle b3InitCreateUserConstraintCommand(b3PhysicsClientHandle physClient, int parentBodyIndex, int parentJointIndex, int childBodyIndex, int childJointIndex, struct b3JointInfo* info);
 

examples/SharedMemory/PhysicsServerCommandProcessor.cpp

@@ -3759,6 +3759,30 @@ bool PhysicsServerCommandProcessor::processCommand(const struct SharedMemoryComm
 						}
 					}
 					
+					if (clientCmd.m_updateFlags & RESET_DYNAMIC_INFO_SET_LATERAL_FRICTION)
+					{
+						int bodyUniqueId = clientCmd.m_resetDynamicInfoArgs.m_bodyUniqueId;
+						int linkIndex = clientCmd.m_resetDynamicInfoArgs.m_linkIndex;
+						double lateralFriction = clientCmd.m_resetDynamicInfoArgs.m_lateralFriction;
+						btAssert(bodyUniqueId >= 0);
+						btAssert(linkIndex >= -1);
+						
+						InteralBodyData* body = m_data->getHandle(bodyUniqueId);
+						if (body && body->m_multiBody)
+						{
+							btMultiBody* mb = body->m_multiBody;
+							if (linkIndex == -1)
+							{
+								mb->getBaseCollider()->setFriction(lateralFriction);
+							}
+							else
+							{
+								mb->getLinkCollider(linkIndex)->setFriction(lateralFriction);
+							}
+						}
+					}
+
+					
 					SharedMemoryStatus& serverCmd =serverStatusOut;
 					serverCmd.m_type = CMD_CLIENT_COMMAND_COMPLETED;
 					hasStatus = true;

examples/SharedMemory/SharedMemoryCommands.h

@@ -110,6 +110,7 @@ enum EnumResetDynamicInfoFlags
 {
 	RESET_DYNAMIC_INFO_SET_MASS=1,
 	RESET_DYNAMIC_INFO_SET_COM=2,
+	RESET_DYNAMIC_INFO_SET_LATERAL_FRICTION=4,
 };
 
 struct ResetDynamicInfoArgs
@@ -118,6 +119,7 @@ struct ResetDynamicInfoArgs
 	int m_linkIndex;
 	double m_mass;
 	double m_COM[3];
+	double m_lateralFriction;
 };
 
 struct SetJointFeedbackArgs

examples/SharedMemory/SharedMemoryPublic.h

@@ -212,7 +212,6 @@ struct b3DynamicInfo
 {
 	double m_mass;
 	double m_localInertialPosition[3];
-	double m_localInertialOrientation[4];
 };
 
 // copied from btMultiBodyLink.h

examples/pybullet/examples/reset_dynamic_info.py

@@ -14,5 +14,7 @@ p.setRealTimeSimulation(0)
 t=0
 while 1:
 	t=t+1
+	if t > 400:
+		p.resetDynamicInfo(bodyUniqueId=0,linkIndex=-1,lateralFriction=0.01)
 	time.sleep(.01)
 	p.stepSimulation()

examples/pybullet/pybullet.c

@@ -609,11 +609,12 @@ static PyObject* pybullet_resetDynamicInfo(PyObject* self, PyObject* args, PyObj
 	int bodyUniqueId = -1;
 	int linkIndex = -2;
 	double mass = -1;
+	double lateralFriction = -1;
 	b3PhysicsClientHandle sm = 0;
 	
 	int physicsClientId = 0;
-	static char* kwlist[] = {"bodyUniqueId", "linkIndex", "mass", "physicsClientId", NULL};
+	static char* kwlist[] = {"bodyUniqueId", "linkIndex", "mass", "lateralFriction", "physicsClientId", NULL};
-	if (!PyArg_ParseTupleAndKeywords(args, keywds, "ii|di", kwlist, &bodyUniqueId, &linkIndex,&mass, &physicsClientId))
+	if (!PyArg_ParseTupleAndKeywords(args, keywds, "ii|ddi", kwlist, &bodyUniqueId, &linkIndex,&mass, &lateralFriction, &physicsClientId))
 	{
 		return NULL;
 	}
@@ -634,6 +635,11 @@ static PyObject* pybullet_resetDynamicInfo(PyObject* self, PyObject* args, PyObj
 			b3ResetDynamicInfoSetMass(command, bodyUniqueId, linkIndex, mass);
 		}
 		
+		if (lateralFriction >= 0)
+		{
+			b3ResetDynamicInfoSetLateralFriction(command, bodyUniqueId, linkIndex, lateralFriction);
+		}
+		
 		statusHandle = b3SubmitClientCommandAndWaitStatus(sm, command);
 	}
 	
@@ -5504,7 +5510,7 @@ static PyMethodDef SpamMethods[] = {
 	 "instantaneously, not through physics simulation."},
 	
 	{"resetDynamicInfo", (PyCFunction)pybullet_resetDynamicInfo, METH_VARARGS | METH_KEYWORDS,
-	 "Reset dynamic information such as mass, COM."},
+	 "Reset dynamic information such as mass, lateral friction coefficient."},
 
 	{"setJointMotorControl", (PyCFunction)pybullet_setJointMotorControl, METH_VARARGS,
 	 "This (obsolete) method cannot select non-zero physicsClientId, use setJointMotorControl2 instead."

src/BulletDynamics/Featherstone/btMultiBody.h

@@ -140,6 +140,11 @@ public:
 		return m_baseCollider;
 	}
 
+	btMultiBodyLinkCollider* getLinkCollider(int index)
+	{
+		return m_colliders[index];
+	}
+
     //
     // get parent
     // input: link num from 0 to num_links-1