Enabling USE_SEPDISTANCE_UTIL2 requires 100% reliable distance computation, but there are issues with large size rations. todo: fix this

Make synchronizeMotionStates() pure virtual in btDynamicsWorld and public in btDiscreteDynamicsWorld. Thanks Chunky.

src/BulletCollision/CollisionDispatch/btConvexConvexAlgorithm.h

@@ -27,7 +27,11 @@ subject to the following restrictions:
 
 class btConvexPenetrationDepthSolver;
 
-#define USE_SEPDISTANCE_UTIL2 1
+///Enabling USE_SEPDISTANCE_UTIL2 requires 100% reliable distance computation. However, when using large size ratios GJK can be imprecise
+///so the distance is not conservative. In that case, enabling this USE_SEPDISTANCE_UTIL2 would result in failing/missing collisions.
+///Either improve GJK for large size ratios (testing a 100 units versus a 0.1 unit object) or only enable the util
+///for certain pairs that have a small size ratio
+///#define USE_SEPDISTANCE_UTIL2 1
 
 ///ConvexConvexAlgorithm collision algorithm implements time of impact, convex closest points and penetration depth calculations.
 class btConvexConvexAlgorithm : public btActivatingCollisionAlgorithm

src/BulletDynamics/Dynamics/btDiscreteDynamicsWorld.h

@@ -60,9 +60,9 @@ protected:
 	
 	virtual void	integrateTransforms(btScalar timeStep);
 		
-	void	calculateSimulationIslands();
+	virtual void	calculateSimulationIslands();
 
-	void	solveConstraints(btContactSolverInfo& solverInfo);
+	virtual void	solveConstraints(btContactSolverInfo& solverInfo);
 	
 	void	updateActivationState(btScalar timeStep);
 
@@ -72,9 +72,8 @@ protected:
 
 	virtual void	internalSingleStepSimulation( btScalar timeStep);
 
-	void	synchronizeMotionStates();
 
-	void	saveKinematicState(btScalar timeStep);
+	virtual void	saveKinematicState(btScalar timeStep);
 
 	void	debugDrawSphere(btScalar radius, const btTransform& transform, const btVector3& color);
 
@@ -90,7 +89,8 @@ public:
 	///if maxSubSteps > 0, it will interpolate motion between fixedTimeStep's
 	virtual int	stepSimulation( btScalar timeStep,int maxSubSteps=1, btScalar fixedTimeStep=btScalar(1.)/btScalar(60.));
 
-	
+
+	virtual void	synchronizeMotionStates();
 
 	void	addConstraint(btTypedConstraint* constraint, bool disableCollisionsBetweenLinkedBodies=false);
 

src/BulletDynamics/Dynamics/btDynamicsWorld.h

@@ -80,6 +80,8 @@ public:
 		virtual void	setGravity(const btVector3& gravity) = 0;
 		virtual btVector3 getGravity () const = 0;
 
+		virtual void	synchronizeMotionStates() = 0;
+
 		virtual void	addRigidBody(btRigidBody* body) = 0;
 
 		virtual void	removeRigidBody(btRigidBody* body) = 0;

src/BulletDynamics/Dynamics/btSimpleDynamicsWorld.h

@@ -60,7 +60,7 @@ public:
 	
 	virtual void	updateAabbs();
 
-	void	synchronizeMotionStates();
+	virtual void	synchronizeMotionStates();
 
 	virtual void	setConstraintSolver(btConstraintSolver* solver);