Introduce kF_UseGjkConvexCastRaytest, and make kF_UseSubSimplexConvexCastRaytest the default for btCollisionWorld::rayTest See https://github.com/bulletphysics/bullet3/issues/34

Add btCollisionObject::setIgnoreCollisionCheck to disable collisions between specific instances, without having a btTypedConstraint. See https://github.com/bulletphysics/bullet3/issues/165

Make btMultiBody and btMultiBodyJointMotor backwards compatible with Bullet 2.82 API (single-DOF API)

src/BulletCollision/CollisionDispatch/btCollisionDispatcher.cpp

@@ -189,7 +189,7 @@ bool	btCollisionDispatcher::needsCollision(const btCollisionObject* body0,const
 
 	if ((!body0->isActive()) && (!body1->isActive()))
 		needsCollision = false;
-	else if (!body0->checkCollideWith(body1))
+	else if ((!body0->checkCollideWith(body1)) || (!body1->checkCollideWith(body0)))
 		needsCollision = false;
 	
 	return needsCollision ;

src/BulletCollision/CollisionDispatch/btCollisionObject.h

@@ -110,13 +110,11 @@ protected:
 	/// If some object should have elaborate collision filtering by sub-classes
 	int			m_checkCollideWith;
 
+	btAlignedObjectArray<const btCollisionObject*> m_objectsWithoutCollisionCheck;
+
 	///internal update revision number. It will be increased when the object changes. This allows some subsystems to perform lazy evaluation.
 	int			m_updateRevision;
 
-	virtual bool	checkCollideWithOverride(const btCollisionObject* /* co */) const
-	{
-		return true;
-	}
 
 public:
 
@@ -225,7 +223,34 @@ public:
 		return m_collisionShape;
 	}
 
-	
+	void	setIgnoreCollisionCheck(const btCollisionObject* co, bool ignoreCollisionCheck)
+	{
+		if (ignoreCollisionCheck)
+		{
+			//We don't check for duplicates. Is it ok to leave that up to the user of this API?
+			//int index = m_objectsWithoutCollisionCheck.findLinearSearch(co);
+			//if (index == m_objectsWithoutCollisionCheck.size())
+			//{
+			m_objectsWithoutCollisionCheck.push_back(co);
+			//}
+		}
+		else
+		{
+			m_objectsWithoutCollisionCheck.remove(co);
+		}
+		m_checkCollideWith = m_objectsWithoutCollisionCheck.size() > 0;
+	}
+
+	virtual bool	checkCollideWithOverride(const btCollisionObject*  co) const
+	{
+		int index = m_objectsWithoutCollisionCheck.findLinearSearch(co);
+		if (index < m_objectsWithoutCollisionCheck.size())
+		{
+			return false;
+		}
+		return true;
+	}
+
 
 	
 

src/BulletCollision/CollisionDispatch/btCollisionWorld.cpp

@@ -294,10 +294,11 @@ void	btCollisionWorld::rayTestSingleInternal(const btTransform& rayFromTrans,con
 		//btContinuousConvexCollision convexCaster(castShape,convexShape,&simplexSolver,0);
 		bool condition = true;
 		btConvexCast* convexCasterPtr = 0;
-		if (resultCallback.m_flags & btTriangleRaycastCallback::kF_UseSubSimplexConvexCastRaytest)
-			convexCasterPtr = &subSimplexConvexCaster;
-		else
+		//use kF_UseSubSimplexConvexCastRaytest by default
+		if (resultCallback.m_flags & btTriangleRaycastCallback::kF_UseGjkConvexCastRaytest)
 			convexCasterPtr = &gjkConvexCaster;
+		else
+			convexCasterPtr = &subSimplexConvexCaster;
 		
 		btConvexCast& convexCaster = *convexCasterPtr;
 

src/BulletCollision/NarrowPhaseCollision/btRaycastCallback.h

@@ -21,6 +21,7 @@ subject to the following restrictions:
 struct btBroadphaseProxy;
 class btConvexShape;
 
+
 class  btTriangleRaycastCallback: public btTriangleCallback
 {
 public:
@@ -32,10 +33,12 @@ public:
    //@BP Mod - allow backface filtering and unflipped normals
    enum EFlags
    {
-      kF_None                 = 0,
+	  kF_None = 0,
       kF_FilterBackfaces      = 1 << 0,
       kF_KeepUnflippedNormal  = 1 << 1,   // Prevents returned face normal getting flipped when a ray hits a back-facing triangle
-	  kF_UseSubSimplexConvexCastRaytest =  1 << 2,   // Uses an approximate but faster ray versus convex intersection algorithm
+		///SubSimplexConvexCastRaytest is the default, even if kF_None is set.
+	  kF_UseSubSimplexConvexCastRaytest = 1 << 2,   // Uses an approximate but faster ray versus convex intersection algorithm
+	  kF_UseGjkConvexCastRaytest = 1 << 3,
       kF_Terminator        = 0xFFFFFFFF
    };
    unsigned int m_flags;