UPBGE: Fix character collision detection. (#866)

Chracter controller is using a ghost object and in particular
a ghost object caching collision pairs named btPairCachingGhostObject.
But with the recent update of bullet, we realized after some bug
reported around character that the caching of collision is not
anymore supported in a safe way.

Instead of fixing the caching mechanism, it was choose to replace
btPairCachingGhostObject by btGhostObject.

The btGhostObject is already maintaining a cache of object overlapping
the only step added is asking the pair cache in the world dispatcher
for the character ghost and one of its overlapping objects.
By this way the character is just reading and not managing duplication
or deletion of manifold in its own cache which is the safest solution.

In the same time the function btSequentialImpulseConstraintSolver::getOrInitSolverBody
is not handling ghost object but only soft, rigid, kinematic and multibody.
An assert is disabled with the adjonction of ghost type check.

Fix issue #838.

extern/bullet/src/BulletDynamics/Character/btKinematicCharacterController.cpp

@@ -132,7 +132,7 @@ btVector3 btKinematicCharacterController::perpindicularComponent (const btVector
 	return direction - parallelComponent(direction, normal);
 }
 
-btKinematicCharacterController::btKinematicCharacterController (btPairCachingGhostObject* ghostObject,btConvexShape* convexShape,btScalar stepHeight, const btVector3& up)
+btKinematicCharacterController::btKinematicCharacterController (btGhostObject* ghostObject,btConvexShape* convexShape,btScalar stepHeight, const btVector3& up)
 {
 	m_ghostObject = ghostObject;
 	m_up.setValue(0.0f, 0.0f, 1.0f);
@@ -170,7 +170,7 @@ btKinematicCharacterController::~btKinematicCharacterController ()
 {
 }
 
-btPairCachingGhostObject* btKinematicCharacterController::getGhostObject()
+btGhostObject* btKinematicCharacterController::getGhostObject()
 {
 	return m_ghostObject;
 }
@@ -194,26 +194,32 @@ bool btKinematicCharacterController::recoverFromPenetration ( btCollisionWorld*
 
 	bool penetration = false;
 
-	collisionWorld->getDispatcher()->dispatchAllCollisionPairs(m_ghostObject->getOverlappingPairCache(), collisionWorld->getDispatchInfo(), collisionWorld->getDispatcher());
-
 	m_currentPosition = m_ghostObject->getWorldTransform().getOrigin();
-
+
+	btOverlappingPairCache *pairCache = collisionWorld->getPairCache();
+	const unsigned int numPairs = m_ghostObject->getNumOverlappingObjects();
+
 //	btScalar maxPen = btScalar(0.0);
-	for (int i = 0; i < m_ghostObject->getOverlappingPairCache()->getNumOverlappingPairs(); i++)
+	for (int i = 0; i < numPairs; i++)
 	{
-		m_manifoldArray.resize(0);
+		btCollisionObject *obj0 = m_ghostObject;
+		btCollisionObject *obj1 = m_ghostObject->getOverlappingObject(i);
 
-		btBroadphasePair* collisionPair = &m_ghostObject->getOverlappingPairCache()->getOverlappingPairArray()[i];
+		btBroadphaseProxy *proxy0 = obj0->getBroadphaseHandle();
+		btBroadphaseProxy *proxy1 = obj1->getBroadphaseHandle();
 
-		btCollisionObject* obj0 = static_cast<btCollisionObject*>(collisionPair->m_pProxy0->m_clientObject);
-        btCollisionObject* obj1 = static_cast<btCollisionObject*>(collisionPair->m_pProxy1->m_clientObject);
+		btBroadphasePair* collisionPair = pairCache->findPair(proxy0, proxy1);
+
+		btAssert(collisionPair);
 
 		if ((obj0 && !obj0->hasContactResponse()) || (obj1 && !obj1->hasContactResponse()))
 			continue;
 
 		if (!needsCollision(obj0, obj1))
 			continue;
-
+
+		m_manifoldArray.resize(0);
+
 		if (collisionPair->m_algorithm)
 			collisionPair->m_algorithm->getAllContactManifolds(m_manifoldArray);
 
@@ -688,11 +694,11 @@ void btKinematicCharacterController::reset ( btCollisionWorld* collisionWorld )
     m_velocityTimeInterval = 0.0;
 
     //clear pair cache
-    btHashedOverlappingPairCache *cache = m_ghostObject->getOverlappingPairCache();
+    /*btHashedOverlappingPairCache *cache = m_ghostObject->getOverlappingPairCache();
     while (cache->getOverlappingPairArray().size() > 0)
     {
             cache->removeOverlappingPair(cache->getOverlappingPairArray()[0].m_pProxy0, cache->getOverlappingPairArray()[0].m_pProxy1, collisionWorld->getDispatcher());
-    }
+    }*/
 }
 
 void btKinematicCharacterController::warp (const btVector3& origin)

extern/bullet/src/BulletDynamics/Character/btKinematicCharacterController.h

@@ -29,7 +29,7 @@ class btConvexShape;
 class btRigidBody;
 class btCollisionWorld;
 class btCollisionDispatcher;
-class btPairCachingGhostObject;
+class btGhostObject;
 
 ///btKinematicCharacterController is an object that supports a sliding motion in a world.
 ///It uses a ghost object and convex sweep test to test for upcoming collisions. This is combined with discrete collision detection to recover from penetrations.
@@ -40,7 +40,7 @@ ATTRIBUTE_ALIGNED16(class) btKinematicCharacterController : public btCharacterCo
 
 	btScalar m_halfHeight;
 
-	btPairCachingGhostObject* m_ghostObject;
+	btGhostObject* m_ghostObject;
 	btConvexShape*	m_convexShape;//is also in m_ghostObject, but it needs to be convex, so we store it here to avoid upcast
 
 	btScalar m_maxPenetrationDepth;
@@ -117,7 +117,7 @@ ATTRIBUTE_ALIGNED16(class) btKinematicCharacterController : public btCharacterCo
 
 	BT_DECLARE_ALIGNED_ALLOCATOR();
 
-	btKinematicCharacterController (btPairCachingGhostObject* ghostObject,btConvexShape* convexShape,btScalar stepHeight, const btVector3& up = btVector3(1.0,0.0,0.0));
+	btKinematicCharacterController (btGhostObject* ghostObject,btConvexShape* convexShape,btScalar stepHeight, const btVector3& up = btVector3(1.0,0.0,0.0));
 	~btKinematicCharacterController ();
 
 
@@ -191,7 +191,7 @@ ATTRIBUTE_ALIGNED16(class) btKinematicCharacterController : public btCharacterCo
 	void setMaxPenetrationDepth(btScalar d);
 	btScalar getMaxPenetrationDepth() const;
 
-	btPairCachingGhostObject* getGhostObject();
+	btGhostObject* getGhostObject();
 	void	setUseGhostSweepTest(bool useGhostObjectSweepTest)
 	{
 		m_useGhostObjectSweepTest = useGhostObjectSweepTest;

extern/bullet/src/BulletDynamics/ConstraintSolver/btSequentialImpulseConstraintSolver.cpp

@@ -785,8 +785,9 @@ int	btSequentialImpulseConstraintSolver::getOrInitSolverBody(btCollisionObject&
     else
     {
 		bool isMultiBodyType = (body.getInternalType()&btCollisionObject::CO_FEATHERSTONE_LINK);
+		const bool isGhostType = (body.getInternalType() & btCollisionObject::CO_GHOST_OBJECT);
         // Incorrectly set collision object flags can degrade performance in various ways.
-		if (!isMultiBodyType)
+		if (!isMultiBodyType && !isGhostType)
 		{
 			btAssert( body.isStaticOrKinematicObject() );
 		}

source/gameengine/Physics/Bullet/CcdPhysicsController.cpp

@@ -58,7 +58,7 @@ float gLinearSleepingTreshold;
 float gAngularSleepingTreshold;
 
 CcdCharacter::CcdCharacter(CcdPhysicsController *ctrl, btMotionState *motionState,
-                           btPairCachingGhostObject *ghost, btConvexShape *shape, float stepHeight)
+                           btGhostObject *ghost, btConvexShape *shape, float stepHeight)
 	:btKinematicCharacterController(ghost, shape, stepHeight, btVector3(0.0f, 0.0f, 1.0f)),
 	m_ctrl(ctrl),
 	m_motionState(motionState),
@@ -510,15 +510,15 @@ bool CcdPhysicsController::CreateCharacterController()
 		return false;
 	}
 
-	m_object = new btPairCachingGhostObject();
+	m_object = new btGhostObject();
 	m_object->setCollisionShape(m_collisionShape);
 	m_object->setCollisionFlags(btCollisionObject::CF_CHARACTER_OBJECT);
 
 	btTransform trans;
 	m_bulletMotionState->getWorldTransform(trans);
 	m_object->setWorldTransform(trans);
 
-	m_characterController = new CcdCharacter(this, m_bulletMotionState, (btPairCachingGhostObject *)m_object,
+	m_characterController = new CcdCharacter(this, m_bulletMotionState, (btGhostObject *)m_object,
 	                                         (btConvexShape *)m_collisionShape, m_cci.m_stepHeight);
 
 	m_characterController->setJumpSpeed(m_cci.m_jumpSpeed);

source/gameengine/Physics/Bullet/CcdPhysicsController.h

@@ -438,7 +438,7 @@ struct CcdConstructionInfo {
 class btRigidBody;
 class btCollisionObject;
 class btSoftBody;
-class btPairCachingGhostObject;
+class btGhostObject;
 
 class CcdCharacter : public btKinematicCharacterController, public PHY_ICharacter
 {
@@ -449,7 +449,7 @@ class CcdCharacter : public btKinematicCharacterController, public PHY_ICharacte
 	unsigned char m_maxJumps;
 
 public:
-	CcdCharacter(CcdPhysicsController *ctrl, btMotionState *motionState, btPairCachingGhostObject *ghost, btConvexShape *shape, float stepHeight);
+	CcdCharacter(CcdPhysicsController *ctrl, btMotionState *motionState, btGhostObject *ghost, btConvexShape *shape, float stepHeight);
 
 	virtual void updateAction(btCollisionWorld *collisionWorld, btScalar dt);