disable constraints when they exceed a breaking threshold, control it with new methods in btTypedConstraint: get/setBreakingImpulseThreshold and get/setEnabled

Disabled constraints are not removed from the world and they use negligible CPU cycles

Demos/ConstraintDemo/ConstraintDemo.cpp

@@ -13,7 +13,6 @@ subject to the following restrictions:
 3. This notice may not be removed or altered from any source distribution.
 */
 
-//#define TEST_SERIALIZATION 1
 
 
 
@@ -29,12 +28,6 @@ subject to the following restrictions:
 #include "GL_ShapeDrawer.h"
 #include "GlutStuff.h"
 
-#ifdef TEST_SERIALIZATION
-#include "LinearMath/btSerializer.h"
-#include "btBulletFile.h"
-#include "btBulletWorldImporter.h"
-#endif //TEST_SERIALIZATION
-
 
 const int numObjects = 3;
 
@@ -121,6 +114,30 @@ void	ConstraintDemo::initPhysics()
 	trans.setOrigin(btVector3(0,20,0));
 
 	float mass = 1.f;
+
+
+#if ENABLE_ALL_DEMOS
+	//point to point constraint with a breaking threshold
+	{
+		trans.setIdentity();
+		trans.setOrigin(btVector3(1,30,-5));
+		localCreateRigidBody( mass,trans,shape);
+		trans.setOrigin(btVector3(0,0,-5));
+
+		btRigidBody* body0 = localCreateRigidBody( mass,trans,shape);
+		trans.setOrigin(btVector3(2*CUBE_HALF_EXTENTS,20,0));
+		mass = 1.f;
+		btRigidBody* body1 = 0;//localCreateRigidBody( mass,trans,shape);
+		btVector3 pivotInA(CUBE_HALF_EXTENTS,CUBE_HALF_EXTENTS,0);
+		btTypedConstraint* p2p = new btPoint2PointConstraint(*body0,pivotInA);
+		m_dynamicsWorld->addConstraint(p2p);
+		p2p ->setBreakingImpulseThreshold(10.2);
+		p2p->setDbgDrawSize(btScalar(5.f));
+	}
+#endif
+
+
+
 #if ENABLE_ALL_DEMOS
 	//point to point constraint (ball socket)
 	{
@@ -141,7 +158,7 @@ void	ConstraintDemo::initPhysics()
 			(body1->getCenterOfMassTransform().getBasis().inverse()*(body1->getCenterOfMassTransform().getBasis() * axisInA)) : 
 		body0->getCenterOfMassTransform().getBasis() * axisInA;
 
-//#define P2P
+#define P2P
 #ifdef P2P
 		btTypedConstraint* p2p = new btPoint2PointConstraint(*body0,pivotInA);
 		//btTypedConstraint* p2p = new btPoint2PointConstraint(*body0,*body1,pivotInA,pivotInB);
@@ -518,27 +535,6 @@ void	ConstraintDemo::initPhysics()
 #endif
 
 
-#ifdef TEST_SERIALIZATION
-
-	int maxSerializeBufferSize = 1024*1024*5;
-
-	btDefaultSerializer*	serializer = new btDefaultSerializer(maxSerializeBufferSize);
-	m_dynamicsWorld->serialize(serializer);
-	
-	FILE* f2 = fopen("testFile.bullet","wb");
-	fwrite(serializer->getBufferPointer(),serializer->getCurrentBufferSize(),1,f2);
-	fclose(f2);
-
-
-	exitPhysics();
-	
-	setupEmptyDynamicsWorld();
-
-	btBulletWorldImporter* fileLoader = new btBulletWorldImporter(m_dynamicsWorld);
-
-	fileLoader->loadFile("testFile.bullet");
-
-#endif //TEST_SERIALIZATION
 
 }
 

Demos/OpenGL/DemoApplication.cpp

@@ -1345,6 +1345,11 @@ void	DemoApplication::clientResetScene()
 
 	if (m_dynamicsWorld)
 	{
+		int numConstraints = m_dynamicsWorld->getNumConstraints();
+		for (i=0;i<numConstraints;i++)
+		{
+			m_dynamicsWorld->getConstraint(0)->setEnabled(true);
+		}
 		numObjects = m_dynamicsWorld->getNumCollisionObjects();
 	
 		///create a copy of the array, not a reference!

src/BulletDynamics/ConstraintSolver/btSequentialImpulseConstraintSolver.cpp

@@ -805,7 +805,14 @@ btScalar btSequentialImpulseConstraintSolver::solveGroupCacheFriendlySetup(btCol
 			for (i=0;i<numConstraints;i++)
 			{
 				btTypedConstraint::btConstraintInfo1& info1 = m_tmpConstraintSizesPool[i];
-				constraints[i]->getInfo1(&info1);
+				if (constraints[i]->isEnabled())
+				{
+					constraints[i]->getInfo1(&info1);
+				} else
+				{
+					info1.m_numConstraintRows = 0;
+					info1.nub = 0;
+				}
 				totalNumRows += info1.m_numConstraintRows;
 			}
 			m_tmpSolverNonContactConstraintPool.resize(totalNumRows);
@@ -826,7 +833,6 @@ btScalar btSequentialImpulseConstraintSolver::solveGroupCacheFriendlySetup(btCol
 					btTypedConstraint* constraint = constraints[i];
 
 
-
 					btRigidBody& rbA = constraint->getRigidBodyA();
 					btRigidBody& rbB = constraint->getRigidBodyB();
 
@@ -835,8 +841,8 @@ btScalar btSequentialImpulseConstraintSolver::solveGroupCacheFriendlySetup(btCol
 					for ( j=0;j<info1.m_numConstraintRows;j++)
 					{
 						memset(&currentConstraintRow[j],0,sizeof(btSolverConstraint));
-						currentConstraintRow[j].m_lowerLimit = -FLT_MAX;
+						currentConstraintRow[j].m_lowerLimit = -SIMD_INFINITY;
-						currentConstraintRow[j].m_upperLimit = FLT_MAX;
+						currentConstraintRow[j].m_upperLimit = SIMD_INFINITY;
 						currentConstraintRow[j].m_appliedImpulse = 0.f;
 						currentConstraintRow[j].m_appliedPushImpulse = 0.f;
 						currentConstraintRow[j].m_solverBodyA = &rbA;
@@ -869,6 +875,18 @@ btScalar btSequentialImpulseConstraintSolver::solveGroupCacheFriendlySetup(btCol
 					info2.m_numIterations = infoGlobal.m_numIterations;
 					constraints[i]->getInfo2(&info2);
 
+					if (currentConstraintRow->m_upperLimit>constraints[i]->getBreakingImpulseThreshold())
+					{
+						currentConstraintRow->m_upperLimit = constraints[i]->getBreakingImpulseThreshold();
+					}
+
+					if (currentConstraintRow->m_lowerLimit<-constraints[i]->getBreakingImpulseThreshold())
+					{
+						currentConstraintRow->m_lowerLimit = -constraints[i]->getBreakingImpulseThreshold();
+					}
+
+
+
 					///finalize the constraint setup
 					for ( j=0;j<info1.m_numConstraintRows;j++)
 					{
@@ -1153,9 +1171,11 @@ btScalar btSequentialImpulseConstraintSolver::solveGroupCacheFriendlyFinish(btCo
 	{
 		const btSolverConstraint& solverConstr = m_tmpSolverNonContactConstraintPool[j];
 		btTypedConstraint* constr = (btTypedConstraint*)solverConstr.m_originalContactPoint;
-		btScalar sum = constr->internalGetAppliedImpulse();
+		constr->internalSetAppliedImpulse(solverConstr.m_appliedImpulse);
-		sum += solverConstr.m_appliedImpulse;
+		if (solverConstr.m_appliedImpulse>constr->getBreakingImpulseThreshold())
-		constr->internalSetAppliedImpulse(sum);
+		{
+			constr->setEnabled(false);
+		}
 	}
 
 

src/BulletDynamics/ConstraintSolver/btTypedConstraint.cpp

@@ -29,7 +29,9 @@ m_needsFeedback(false),
 m_rbA(rbA),
 m_rbB(getFixedBody()),
 m_appliedImpulse(btScalar(0.)),
-m_dbgDrawSize(DEFAULT_DEBUGDRAW_SIZE)
+m_dbgDrawSize(DEFAULT_DEBUGDRAW_SIZE),
+m_breakingImpulseThreshold(SIMD_INFINITY),
+m_isEnabled(true)
 {
 }
 
@@ -42,7 +44,9 @@ m_needsFeedback(false),
 m_rbA(rbA),
 m_rbB(rbB),
 m_appliedImpulse(btScalar(0.)),
-m_dbgDrawSize(DEFAULT_DEBUGDRAW_SIZE)
+m_dbgDrawSize(DEFAULT_DEBUGDRAW_SIZE),
+m_breakingImpulseThreshold(SIMD_INFINITY),
+m_isEnabled(true)
 {
 }
 

src/BulletDynamics/ConstraintSolver/btTypedConstraint.h

@@ -62,6 +62,10 @@ class btTypedConstraint : public btTypedObject
 		void* m_userConstraintPtr;
 	};
 
+	btScalar	m_breakingImpulseThreshold;
+	bool		m_isEnabled;
+
+
 	bool m_needsFeedback;
 
 	btTypedConstraint&	operator=(btTypedConstraint&	other)
@@ -155,6 +159,28 @@ public:
 		return m_appliedImpulse;
 	}
 
+
+	btScalar	getBreakingImpulseThreshold() const
+	{
+		return 	m_breakingImpulseThreshold;
+	}
+
+	void	setBreakingImpulseThreshold(btScalar threshold)
+	{
+		m_breakingImpulseThreshold = threshold;
+	}
+
+	bool	isEnabled() const
+	{
+		return m_isEnabled;
+	}
+
+	void	setEnabled(bool enabled)
+	{
+		m_isEnabled=enabled;
+	}
+
+
 	///internal method used by the constraint solver, don't use them directly
 	virtual	void	solveConstraintObsolete(btRigidBody& /*bodyA*/,btRigidBody& /*bodyB*/,btScalar	/*timeStep*/) {};
 

src/BulletMultiThreaded/btParallelConstraintSolver.cpp

@@ -1165,11 +1165,8 @@ btScalar btParallelConstraintSolver::solveGroup(btCollisionObject** bodies1,int
 				if (info1.m_numConstraintRows)
 				{
 					btAssert(currentRow<totalNumRows);
-
-					btSolverConstraint* currentConstraintRow = &m_tmpSolverNonContactConstraintPool[currentRow];
 					btTypedConstraint* constraint = constraints[i];
-
+					btSolverConstraint* currentConstraintRow = &m_tmpSolverNonContactConstraintPool[currentRow];
-
 
 					btRigidBody& rbA = constraint->getRigidBodyA();
 					btRigidBody& rbB = constraint->getRigidBodyB();
@@ -1212,6 +1209,7 @@ btScalar btParallelConstraintSolver::solveGroup(btCollisionObject** bodies1,int
 					info2.m_numIterations = infoGlobal.m_numIterations;
 					constraints[i]->getInfo2(&info2);
 
+					
 					int idA = constraint->getRigidBodyA().getCompanionId();
 					int idB = constraint->getRigidBodyB().getCompanionId();