add support to btHingeConstraint to set/get ERP, example use:

hinge->setParam(BT_CONSTRAINT_ERP,0.5);
btScalar erp = hinge->getParam(BT_CONSTRAINT_ERP);
Also, preliminary support for status bar messages in demo framework.

Demos3/AllBullet2Demos/main.cpp

@@ -356,6 +356,11 @@ void selectDemo(int demoIndex)
 		sCurrentDemo = (*allDemos[demoIndex].m_createFunc)(app);
 		if (sCurrentDemo)
 		{
+			if (gui)
+			{
+				bool isLeft = true;
+				gui->setStatusBarMessage("Status: OK", false);
+			}
 			sCurrentDemo->initPhysics();
 		}
 	}
@@ -382,6 +387,28 @@ void	MyComboBoxCallback(int comboId, const char* item)
 }
 
 
+
+void MyStatusBarPrintf(const char* msg)
+{
+	printf("b3Printf: %s\n", msg);
+	if (gui)
+	{
+		bool isLeft = true;
+		gui->setStatusBarMessage(msg,isLeft);
+	}
+}
+
+
+void MyStatusBarWarning(const char* msg)
+{
+	printf("Warning: %s\n", msg);
+	if (gui)
+	{
+		bool isLeft = false;
+		gui->setStatusBarMessage(msg,isLeft);
+	}
+}
+
 struct MyMenuItemHander :public Gwen::Event::Handler
 {
 	int					m_buttonId;
@@ -530,6 +557,10 @@ int main(int argc, char* argv[])
 	app->m_renderer->setCameraPitch(0);
 	app->m_renderer->setCameraTargetPosition(0,0,0);
 
+	b3SetCustomWarningMessageFunc(MyStatusBarWarning);
+	b3SetCustomPrintfFunc(MyStatusBarPrintf);
+	
+
 	/*
 	SimpleOpenGL3App* app = new SimpleOpenGL3App("AllBullet2Demos",width,height);
 	s_instancingRenderer->setCameraDistance(13);

Demos3/bullet2/ConstraintDemo/ConstraintPhysicsSetup.cpp

@@ -19,9 +19,12 @@ void ConstraintPhysicsSetup::stepSimulation(float deltaTime)
 }
 
 
+#include "Bullet3Common/b3Logging.h"
 
 void ConstraintPhysicsSetup::initPhysics(GraphicsPhysicsBridge& gfxBridge)
 {
+	b3Printf(__FILE__);
+
 	gfxBridge.setUpAxis(1);
 	
 	createEmptyDynamicsWorld();
@@ -51,6 +54,8 @@ slider.m_maxVal=720;
 		btVector3 btAxisA( 0.0f, 1.0f, 0.0f ); // pointing upwards, aka Y-axis
 
 		spDoorHinge = new btHingeAccumulatedAngleConstraint( *pDoorBody, btPivotA, btAxisA );
+		spDoorHinge->setParam(BT_CONSTRAINT_ERP,0.5);
+		btScalar erp = spDoorHinge->getParam(BT_CONSTRAINT_ERP);
 
 //		spDoorHinge->setLimit( 0.0f, SIMD_PI_2 );
 		// test problem values

src/BulletDynamics/ConstraintSolver/btHingeConstraint.cpp

@@ -45,7 +45,11 @@ btHingeConstraint::btHingeConstraint(btRigidBody& rbA,btRigidBody& rbB, const bt
 									 m_useSolveConstraintObsolete(HINGE_USE_OBSOLETE_SOLVER),
 									 m_useOffsetForConstraintFrame(HINGE_USE_FRAME_OFFSET),
 									 m_useReferenceFrameA(useReferenceFrameA),
-									 m_flags(0)
+									 m_flags(0),
+									 m_normalCFM(0),
+									 m_normalERP(0),
+									 m_stopCFM(0),
+									 m_stopERP(0)
 {
 	m_rbAFrame.getOrigin() = pivotInA;
 	
@@ -101,7 +105,11 @@ m_angularOnly(false), m_enableAngularMotor(false),
 m_useSolveConstraintObsolete(HINGE_USE_OBSOLETE_SOLVER),
 m_useOffsetForConstraintFrame(HINGE_USE_FRAME_OFFSET),
 m_useReferenceFrameA(useReferenceFrameA),
-m_flags(0)
+m_flags(0),
+m_normalCFM(0),
+m_normalERP(0),
+m_stopCFM(0),
+m_stopERP(0)
 {
 
 	// since no frame is given, assume this to be zero angle and just pick rb transform axis
@@ -151,7 +159,11 @@ m_enableAngularMotor(false),
 m_useSolveConstraintObsolete(HINGE_USE_OBSOLETE_SOLVER),
 m_useOffsetForConstraintFrame(HINGE_USE_FRAME_OFFSET),
 m_useReferenceFrameA(useReferenceFrameA),
-m_flags(0)
+m_flags(0),
+m_normalCFM(0),
+m_normalERP(0),
+m_stopCFM(0),
+m_stopERP(0)
 {
 #ifndef	_BT_USE_CENTER_LIMIT_
 	//start with free
@@ -177,7 +189,11 @@ m_enableAngularMotor(false),
 m_useSolveConstraintObsolete(HINGE_USE_OBSOLETE_SOLVER),
 m_useOffsetForConstraintFrame(HINGE_USE_FRAME_OFFSET),
 m_useReferenceFrameA(useReferenceFrameA),
-m_flags(0)
+m_flags(0),
+m_normalCFM(0),
+m_normalERP(0),
+m_stopCFM(0),
+m_stopERP(0)
 {
 	///not providing rigidbody B means implicitly using worldspace for body B
 
@@ -331,6 +347,7 @@ void btHingeAccumulatedAngleConstraint::getInfo1(btConstraintInfo1* info)
 	m_accumulatedAngle = btShortestAngleUpdate(m_accumulatedAngle,curHingeAngle);
 
 	btHingeConstraint::getInfo1(info);
+	
 }
 
 
@@ -464,7 +481,9 @@ void btHingeConstraint::getInfo2Internal(btConstraintInfo2* info, const btTransf
 		a2.getSkewSymmetricMatrix(angular0,angular1,angular2);
 	}
 	// linear RHS
-    btScalar k = info->fps * info->erp;
+	btScalar normalErp = (m_flags & BT_HINGE_FLAGS_ERP_NORM) ? m_normalERP : info->erp;
+
+    btScalar k = info->fps * normalErp;
 	if (!m_angularOnly)
 	{
 		for(i = 0; i < 3; i++)
@@ -561,7 +580,7 @@ void btHingeConstraint::getInfo2Internal(btConstraintInfo2* info, const btTransf
 			powered = 0;
 		}
 		info->m_constraintError[srow] = btScalar(0.0f);
-		btScalar currERP = (m_flags & BT_HINGE_FLAGS_ERP_STOP) ? m_stopERP : info->erp;
+		btScalar currERP = (m_flags & BT_HINGE_FLAGS_ERP_STOP) ? m_stopERP : normalErp;
 		if(powered)
 		{
 			if(m_flags & BT_HINGE_FLAGS_CFM_NORM)
@@ -851,7 +870,8 @@ void btHingeConstraint::getInfo2InternalUsingFrameOffset(btConstraintInfo2* info
 	for (i=0; i<3; i++) info->m_J1angularAxis[s2+i] = tmpA[i];
     for (i=0; i<3; i++) info->m_J2angularAxis[s2+i] = -tmpB[i];
 
-	btScalar k = info->fps * info->erp;
+	btScalar normalErp = (m_flags & BT_HINGE_FLAGS_ERP_NORM)? m_normalERP : info->erp;
+	btScalar k = info->fps * normalErp;
 
 	if (!m_angularOnly)
 	{
@@ -909,7 +929,8 @@ void btHingeConstraint::getInfo2InternalUsingFrameOffset(btConstraintInfo2* info
 	//    angular_velocity  = (erp*fps) * (ax1 x ax2)
 	// ax1 x ax2 is in the plane space of ax1, so we project the angular
 	// velocity to p and q to find the right hand side.
-	k = info->fps * info->erp;
+	k = info->fps * normalErp;//??
+
 	btVector3 u = ax1A.cross(ax1B);
 	info->m_constraintError[s3] = k * u.dot(p);
 	info->m_constraintError[s4] = k * u.dot(q);
@@ -954,7 +975,7 @@ void btHingeConstraint::getInfo2InternalUsingFrameOffset(btConstraintInfo2* info
 			powered = 0;
 		}
 		info->m_constraintError[srow] = btScalar(0.0f);
-		btScalar currERP = (m_flags & BT_HINGE_FLAGS_ERP_STOP) ? m_stopERP : info->erp;
+		btScalar currERP = (m_flags & BT_HINGE_FLAGS_ERP_STOP) ? m_stopERP : normalErp;
 		if(powered)
 		{
 			if(m_flags & BT_HINGE_FLAGS_CFM_NORM)
@@ -1055,6 +1076,10 @@ void btHingeConstraint::setParam(int num, btScalar value, int axis)
 				m_normalCFM = value;
 				m_flags |= BT_HINGE_FLAGS_CFM_NORM;
 				break;
+			case BT_CONSTRAINT_ERP:
+				m_normalERP = value;
+				m_flags |= BT_HINGE_FLAGS_ERP_NORM;
+				break;
 			default : 
 				btAssertConstrParams(0);
 		}
@@ -1085,6 +1110,10 @@ btScalar btHingeConstraint::getParam(int num, int axis) const
 				btAssertConstrParams(m_flags & BT_HINGE_FLAGS_CFM_NORM);
 				retVal = m_normalCFM;
 				break;
+			case BT_CONSTRAINT_ERP:
+				btAssertConstrParams(m_flags & BT_HINGE_FLAGS_ERP_NORM);
+				retVal = m_normalERP;
+				break;
 			default : 
 				btAssertConstrParams(0);
 		}

src/BulletDynamics/ConstraintSolver/btHingeConstraint.h

@@ -41,7 +41,8 @@ enum btHingeFlags
 {
 	BT_HINGE_FLAGS_CFM_STOP = 1,
 	BT_HINGE_FLAGS_ERP_STOP = 2,
-	BT_HINGE_FLAGS_CFM_NORM = 4
+	BT_HINGE_FLAGS_CFM_NORM = 4,
+	BT_HINGE_FLAGS_ERP_NORM = 8
 };
 
 
@@ -94,6 +95,7 @@ public:
 
 	int			m_flags;
 	btScalar	m_normalCFM;
+	btScalar	m_normalERP;
 	btScalar	m_stopCFM;
 	btScalar	m_stopERP;