From ce0bdd891d7f96112a6388a9f97557dff8442ec9 Mon Sep 17 00:00:00 2001
From: "erwin.coumans" <erwin.coumans@08e121b0-ae19-0410-a57b-3be3395fd4fd>
Date: Sat, 8 Nov 2008 19:34:05 +0000
Subject: [PATCH] added synchronizeSingleMotionState, thanks Chunky.

---
 .../Dynamics/btDiscreteDynamicsWorld.cpp      | 34 ++++++++++++-------
 .../Dynamics/btDiscreteDynamicsWorld.h        |  3 ++
 2 files changed, 24 insertions(+), 13 deletions(-)

diff --git a/src/BulletDynamics/Dynamics/btDiscreteDynamicsWorld.cpp b/src/BulletDynamics/Dynamics/btDiscreteDynamicsWorld.cpp
index cd2fdedb6..f67a8228a 100644
--- a/src/BulletDynamics/Dynamics/btDiscreteDynamicsWorld.cpp
+++ b/src/BulletDynamics/Dynamics/btDiscreteDynamicsWorld.cpp
@@ -250,6 +250,25 @@ void	btDiscreteDynamicsWorld::applyGravity()
 }
 
 
+void	btDiscreteDynamicsWorld::synchronizeSingleMotionState(btRigidBody* body)
+{
+	btAssert(body);
+
+	if (body->getMotionState() && !body->isStaticOrKinematicObject())
+	{
+		//we need to call the update at least once, even for sleeping objects
+		//otherwise the 'graphics' transform never updates properly
+		///@todo: add 'dirty' flag
+		//if (body->getActivationState() != ISLAND_SLEEPING)
+		{
+			btTransform interpolatedTransform;
+			btTransformUtil::integrateTransform(body->getInterpolationWorldTransform(),
+				body->getInterpolationLinearVelocity(),body->getInterpolationAngularVelocity(),m_localTime*body->getHitFraction(),interpolatedTransform);
+			body->getMotionState()->setWorldTransform(interpolatedTransform);
+		}
+	}
+}
+
 
 void	btDiscreteDynamicsWorld::synchronizeMotionStates()
 {
@@ -261,19 +280,8 @@ void	btDiscreteDynamicsWorld::synchronizeMotionStates()
 			btCollisionObject* colObj = m_activeObjects[i];
 			
 			btRigidBody* body = btRigidBody::upcast(colObj);
-			if (body && body->getMotionState() && !body->isStaticOrKinematicObject())
-			{
-				//we need to call the update at least once, even for sleeping objects
-				//otherwise the 'graphics' transform never updates properly
-				///@todo: add 'dirty' flag
-				//if (body->getActivationState() != ISLAND_SLEEPING)
-				{
-					btTransform interpolatedTransform;
-					btTransformUtil::integrateTransform(body->getInterpolationWorldTransform(),
-						body->getInterpolationLinearVelocity(),body->getInterpolationAngularVelocity(),m_localTime*body->getHitFraction(),interpolatedTransform);
-					body->getMotionState()->setWorldTransform(interpolatedTransform);
-				}
-			}
+			if (body)
+				synchronizeSingleMotionState(body);
 		}
 	}
 
diff --git a/src/BulletDynamics/Dynamics/btDiscreteDynamicsWorld.h b/src/BulletDynamics/Dynamics/btDiscreteDynamicsWorld.h
index 646b3f4e3..724f19a49 100644
--- a/src/BulletDynamics/Dynamics/btDiscreteDynamicsWorld.h
+++ b/src/BulletDynamics/Dynamics/btDiscreteDynamicsWorld.h
@@ -92,6 +92,9 @@ public:
 
 	virtual void	synchronizeMotionStates();
 
+	///this can be useful to synchronize a single rigid body -> graphics object
+	void	synchronizeSingleMotionState(btRigidBody* body);
+
 	void	addConstraint(btTypedConstraint* constraint, bool disableCollisionsBetweenLinkedBodies=false);
 
 	void	removeConstraint(btTypedConstraint* constraint);