Added a very basic dynamics demo, only using spheres (and optionally boxes)

src/BulletCollision/CollisionDispatch/btCollisionDispatcher.cpp

@@ -32,6 +32,27 @@ int gNumManifold = 0;
 #include <stdio.h>
 
 	
+btCollisionDispatcher::btCollisionDispatcher(bool noDefaultAlgorithms)
+:m_useIslands(true),
+m_count(0),
+m_convexConvexCreateFunc(0),
+m_convexConcaveCreateFunc(0),
+m_swappedConvexConcaveCreateFunc(0),
+m_compoundCreateFunc(0),
+m_swappedCompoundCreateFunc(0),
+m_emptyCreateFunc(0)
+{
+	int i;
+
+	m_emptyCreateFunc = new btEmptyAlgorithm::CreateFunc;
+	for (i=0;i<MAX_BROADPHASE_COLLISION_TYPES;i++)
+	{
+		for (int j=0;j<MAX_BROADPHASE_COLLISION_TYPES;j++)
+		{
+			m_doubleDispatch[i][j] = m_emptyCreateFunc;
+		}
+	}
+}
 
 	
 btCollisionDispatcher::btCollisionDispatcher (): 

src/BulletCollision/CollisionDispatch/btCollisionDispatcher.h

@@ -56,8 +56,7 @@ class btCollisionDispatcher : public btDispatcher
 	btCollisionAlgorithmCreateFunc*	m_swappedCompoundCreateFunc;
 	btCollisionAlgorithmCreateFunc*   m_emptyCreateFunc;
 
-	
-
+	btCollisionAlgorithm* internalFindAlgorithm(btCollisionObject* body0,btCollisionObject* body1);
 
 public:
 
@@ -99,7 +98,12 @@ public:
 
 	int m_count;
 	
+	///the default constructor creates/register default collision algorithms, for convex, compound and concave shape support
 	btCollisionDispatcher ();
+
+	///a special constructor that doesn't create/register the default collision algorithms
+	btCollisionDispatcher(bool noDefaultAlgorithms);
+
 	virtual ~btCollisionDispatcher();
 
 	virtual btPersistentManifold*	getNewManifold(void* b0,void* b1);
@@ -111,9 +115,7 @@ public:
 
 			
 	btCollisionAlgorithm* findAlgorithm(btCollisionObject* body0,btCollisionObject* body1);
-	
-	btCollisionAlgorithm* internalFindAlgorithm(btCollisionObject* body0,btCollisionObject* body1);
-	
+		
 	virtual bool	needsCollision(btCollisionObject* body0,btCollisionObject* body1);
 	
 	virtual bool	needsResponse(btCollisionObject* body0,btCollisionObject* body1);

src/BulletCollision/CollisionDispatch/btSphereBoxCollisionAlgorithm.cpp

@@ -26,10 +26,12 @@ m_ownManifold(false),
 m_manifoldPtr(mf),
 m_isSwapped(isSwapped)
 {
+	btCollisionObject* sphereObj = m_isSwapped? col1 : col0;
+	btCollisionObject* boxObj = m_isSwapped? col0 : col1;
 	
-	if (!m_manifoldPtr && m_dispatcher->needsCollision(col0,col1))
+	if (!m_manifoldPtr && m_dispatcher->needsCollision(sphereObj,boxObj))
 	{
-		m_manifoldPtr = m_dispatcher->getNewManifold(col0,col1);
+		m_manifoldPtr = m_dispatcher->getNewManifold(sphereObj,boxObj);
 		m_ownManifold = true;
 	}
 }

src/BulletDynamics/Dynamics/btSimpleDynamicsWorld.cpp

@@ -47,7 +47,7 @@ btSimpleDynamicsWorld::~btSimpleDynamicsWorld()
 		delete m_constraintSolver;
 }
 
-void	btSimpleDynamicsWorld::stepSimulation(float timeStep)
+void	btSimpleDynamicsWorld::stepSimulation(float timeStep,int numSubsteps)
 {
 	///apply gravity, predict motion
 	predictUnconstraintMotion(timeStep);
@@ -56,12 +56,16 @@ void	btSimpleDynamicsWorld::stepSimulation(float timeStep)
 	performDiscreteCollisionDetection();
 
 	///solve contact constraints
-	btPersistentManifold** manifoldPtr = ((btCollisionDispatcher*)m_dispatcher1)->getInternalManifoldPointer();
 	int numManifolds = m_dispatcher1->getNumManifolds();
-	btContactSolverInfo infoGlobal;
-	infoGlobal.m_timeStep = timeStep;
-	
-	m_constraintSolver->solveGroup(manifoldPtr, numManifolds,infoGlobal,m_debugDrawer);
+	if (numManifolds)
+	{
+		btPersistentManifold** manifoldPtr = ((btCollisionDispatcher*)m_dispatcher1)->getInternalManifoldPointer();
+		
+		btContactSolverInfo infoGlobal;
+		infoGlobal.m_timeStep = timeStep;
+		
+		m_constraintSolver->solveGroup(manifoldPtr, numManifolds,infoGlobal,m_debugDrawer);
+	}
 
 	///integrate transforms
 	integrateTransforms(timeStep);

src/BulletDynamics/Dynamics/btSimpleDynamicsWorld.h

@@ -54,7 +54,7 @@ public:
 
 	virtual ~btSimpleDynamicsWorld();
 		
-	virtual void	stepSimulation( float timeStep);
+	virtual void	stepSimulation( float timeStep,int numSubsteps=1);
 
 	virtual void	setDebugDrawer(btIDebugDraw*	debugDrawer) 
 	{

src/btBulletCollisionCommon.h

@@ -41,7 +41,7 @@ subject to the following restrictions:
 
 ///Narrowphase Collision Detector
 #include "BulletCollision/CollisionDispatch/btSphereSphereCollisionAlgorithm.h"
-
+#include "BulletCollision/CollisionDispatch/btSphereBoxCollisionAlgorithm.h"
 
 ///Dispatching and generation of collision pairs (broadphase)
 #include "BulletCollision/CollisionDispatch/btCollisionDispatcher.h"