Add a convenience method to control the number of single-shot contact points for convex-convex collision detection, using the perturbation method.

(btDefaultCollisionConfiguration::setConvexConvexMultipointIterations)
Default value is zero, for best performance.

src/BulletCollision/CollisionDispatch/btDefaultCollisionConfiguration.cpp

@@ -288,3 +288,10 @@ btCollisionAlgorithmCreateFunc* btDefaultCollisionConfiguration::getCollisionAlg
 	//failed to find an algorithm
 	return m_emptyCreateFunc;
 }
+
+void btDefaultCollisionConfiguration::setConvexConvexMultipointIterations(int numPerturbationIterations, int minimumPointsPerturbationThreshold)
+{
+	btConvexConvexAlgorithm::CreateFunc* convexConvex = (btConvexConvexAlgorithm::CreateFunc*) m_convexConvexCreateFunc;
+	convexConvex->m_numPerturbationIterations = numPerturbationIterations;
+	convexConvex->m_minimumPointsPerturbationThreshold = minimumPointsPerturbationThreshold;
+}

src/BulletCollision/CollisionDispatch/btDefaultCollisionConfiguration.h

@@ -111,6 +111,14 @@ public:
 
 	virtual btCollisionAlgorithmCreateFunc* getCollisionAlgorithmCreateFunc(int proxyType0,int proxyType1);
 
+	///Use this method to allow to generate multiple contact points between at once, between two objects using the generic convex-convex algorithm.
+	///By default, this feature is disabled for best performance.
+	///@param numPerturbationIterations controls the number of collision queries. Set it to zero to disable the feature.
+	///@param minimumPointsPerturbationThreshold is the minimum number of points in the contact cache, above which the feature is disabled
+	///3 is a good value for both params, if you want to enable the feature. This is because the default contact cache contains a maximum of 4 points, and one collision query at the unperturbed orientation is performed first.
+	///See Bullet/Demos/CollisionDemo for an example how this feature gathers multiple points.
+	///@todo we could add a per-object setting of those parameters, for level-of-detail collision detection.
+	void	setConvexConvexMultipointIterations(int numPerturbationIterations=3, int minimumPointsPerturbationThreshold = 3);
 
 };