示例#1
0
        public static void DebugDrawConstraint(TypedConstraint constraint, IDebugDraw debugDraw)
        {
            bool  drawFrames  = (debugDraw.GetDebugMode() & DebugDrawModes.DBG_DrawConstraints) != 0;
            bool  drawLimits  = (debugDraw.GetDebugMode() & DebugDrawModes.DBG_DrawConstraintLimits) != 0;
            float dbgDrawSize = constraint.GetDbgDrawSize();

            if (dbgDrawSize <= 0f)
            {
                return;
            }

            switch (constraint.GetConstraintType())
            {
            case TypedConstraintType.POINT2POINT_CONSTRAINT_TYPE:
            {
                Point2PointConstraint p2pC  = constraint as Point2PointConstraint;
                IndexedMatrix         tr    = IndexedMatrix.Identity;
                IndexedVector3        pivot = p2pC.GetPivotInA();
                pivot      = p2pC.GetRigidBodyA().GetCenterOfMassTransform() * pivot;
                tr._origin = pivot;
                debugDraw.DrawTransform(ref tr, dbgDrawSize);
                // that ideally should draw the same frame
                pivot      = p2pC.GetPivotInB();
                pivot      = p2pC.GetRigidBodyB().GetCenterOfMassTransform() * pivot;
                tr._origin = pivot;
                if (drawFrames)
                {
                    debugDraw.DrawTransform(ref tr, dbgDrawSize);
                }
            }
            break;

            case TypedConstraintType.HINGE_CONSTRAINT_TYPE:
            {
                HingeConstraint pHinge = constraint as HingeConstraint;
                IndexedMatrix   tr     = pHinge.GetRigidBodyA().GetCenterOfMassTransform() * pHinge.GetAFrame();
                if (drawFrames)
                {
                    debugDraw.DrawTransform(ref tr, dbgDrawSize);
                }
                tr = pHinge.GetRigidBodyB().GetCenterOfMassTransform() * pHinge.GetBFrame();
                if (drawFrames)
                {
                    debugDraw.DrawTransform(ref tr, dbgDrawSize);
                }
                float minAng = pHinge.GetLowerLimit();
                float maxAng = pHinge.GetUpperLimit();
                if (minAng == maxAng)
                {
                    break;
                }
                bool drawSect = true;
                if (minAng > maxAng)
                {
                    minAng   = 0f;
                    maxAng   = MathUtil.SIMD_2_PI;
                    drawSect = false;
                }
                if (drawLimits)
                {
                    IndexedVector3 center = tr._origin;
                    IndexedVector3 normal = tr._basis.GetColumn(2);
                    IndexedVector3 axis   = tr._basis.GetColumn(0);
                    IndexedVector3 zero   = IndexedVector3.Zero;
                    debugDraw.DrawArc(ref center, ref normal, ref axis, dbgDrawSize, dbgDrawSize, minAng, maxAng, ref zero, drawSect);
                }
            }
            break;

            case TypedConstraintType.CONETWIST_CONSTRAINT_TYPE:
            {
                ConeTwistConstraint pCT = constraint as ConeTwistConstraint;
                IndexedMatrix       tr  = pCT.GetRigidBodyA().GetCenterOfMassTransform() * pCT.GetAFrame();
                if (drawFrames)
                {
                    debugDraw.DrawTransform(ref tr, dbgDrawSize);
                }
                tr = pCT.GetRigidBodyB().GetCenterOfMassTransform() * pCT.GetBFrame();
                if (drawFrames)
                {
                    debugDraw.DrawTransform(ref tr, dbgDrawSize);
                }
                IndexedVector3 zero = IndexedVector3.Zero;

                if (drawLimits)
                {
                    //const float length = float(5);
                    float          length          = dbgDrawSize;
                    const int      nSegments       = 8 * 4;
                    float          fAngleInRadians = MathUtil.SIMD_2_PI * (float)(nSegments - 1) / (float)nSegments;
                    IndexedVector3 pPrev           = pCT.GetPointForAngle(fAngleInRadians, length);
                    pPrev = tr * pPrev;
                    for (int i = 0; i < nSegments; i++)
                    {
                        fAngleInRadians = MathUtil.SIMD_2_PI * (float)i / (float)nSegments;
                        IndexedVector3 pCur = pCT.GetPointForAngle(fAngleInRadians, length);
                        pCur = tr * pCur;
                        debugDraw.DrawLine(ref pPrev, ref pCur, ref zero);

                        if (i % (nSegments / 8) == 0)
                        {
                            IndexedVector3 origin = tr._origin;
                            debugDraw.DrawLine(ref origin, ref pCur, ref zero);
                        }

                        pPrev = pCur;
                    }
                    float tws       = pCT.GetTwistSpan();
                    float twa       = pCT.GetTwistAngle();
                    bool  useFrameB = (pCT.GetRigidBodyB().GetInvMass() > 0f);
                    if (useFrameB)
                    {
                        tr = pCT.GetRigidBodyB().GetCenterOfMassTransform() * pCT.GetBFrame();
                    }
                    else
                    {
                        tr = pCT.GetRigidBodyA().GetCenterOfMassTransform() * pCT.GetAFrame();
                    }
                    IndexedVector3 pivot  = tr._origin;
                    IndexedVector3 normal = tr._basis.GetColumn(0);
                    IndexedVector3 axis   = tr._basis.GetColumn(1);

                    debugDraw.DrawArc(ref pivot, ref normal, ref axis, dbgDrawSize, dbgDrawSize, -twa - tws, -twa + tws, ref zero, true);
                }
            }
            break;

            case TypedConstraintType.D6_CONSTRAINT_TYPE:
            case TypedConstraintType.D6_SPRING_CONSTRAINT_TYPE:
            {
                Generic6DofConstraint p6DOF = constraint as Generic6DofConstraint;
                IndexedMatrix         tr    = p6DOF.GetCalculatedTransformA();
                if (drawFrames)
                {
                    debugDraw.DrawTransform(ref tr, dbgDrawSize);
                }
                tr = p6DOF.GetCalculatedTransformB();
                if (drawFrames)
                {
                    debugDraw.DrawTransform(ref tr, dbgDrawSize);
                }
                IndexedVector3 zero = IndexedVector3.Zero;
                if (drawLimits)
                {
                    tr = p6DOF.GetCalculatedTransformA();
                    IndexedVector3 center = p6DOF.GetCalculatedTransformB()._origin;
                    // up is axis 1 not 2 ?

                    IndexedVector3 up    = tr._basis.GetColumn(1);
                    IndexedVector3 axis  = tr._basis.GetColumn(0);
                    float          minTh = p6DOF.GetRotationalLimitMotor(1).m_loLimit;
                    float          maxTh = p6DOF.GetRotationalLimitMotor(1).m_hiLimit;
                    float          minPs = p6DOF.GetRotationalLimitMotor(2).m_loLimit;
                    float          maxPs = p6DOF.GetRotationalLimitMotor(2).m_hiLimit;
                    debugDraw.DrawSpherePatch(ref center, ref up, ref axis, dbgDrawSize * .9f, minTh, maxTh, minPs, maxPs, ref zero);
                    axis = tr._basis.GetColumn(1);
                    float          ay   = p6DOF.GetAngle(1);
                    float          az   = p6DOF.GetAngle(2);
                    float          cy   = (float)Math.Cos(ay);
                    float          sy   = (float)Math.Sin(ay);
                    float          cz   = (float)Math.Cos(az);
                    float          sz   = (float)Math.Sin(az);
                    IndexedVector3 ref1 = new IndexedVector3(
                        cy * cz * axis.X + cy * sz * axis.Y - sy * axis.Z,
                        -sz * axis.X + cz * axis.Y,
                        cz * sy * axis.X + sz * sy * axis.Y + cy * axis.Z);
                    tr = p6DOF.GetCalculatedTransformB();
                    IndexedVector3 normal = -tr._basis.GetColumn(0);
                    float          minFi  = p6DOF.GetRotationalLimitMotor(0).m_loLimit;
                    float          maxFi  = p6DOF.GetRotationalLimitMotor(0).m_hiLimit;
                    if (minFi > maxFi)
                    {
                        debugDraw.DrawArc(ref center, ref normal, ref ref1, dbgDrawSize, dbgDrawSize, -MathUtil.SIMD_PI, MathUtil.SIMD_PI, ref zero, false);
                    }
                    else if (minFi < maxFi)
                    {
                        debugDraw.DrawArc(ref center, ref normal, ref ref1, dbgDrawSize, dbgDrawSize, minFi, maxFi, ref zero, false);
                    }
                    tr = p6DOF.GetCalculatedTransformA();
                    IndexedVector3 bbMin = p6DOF.GetTranslationalLimitMotor().m_lowerLimit;
                    IndexedVector3 bbMax = p6DOF.GetTranslationalLimitMotor().m_upperLimit;
                    debugDraw.DrawBox(ref bbMin, ref bbMax, ref tr, ref zero);
                }
            }
            break;

            case TypedConstraintType.SLIDER_CONSTRAINT_TYPE:
            {
                SliderConstraint pSlider = constraint as SliderConstraint;
                IndexedMatrix    tr      = pSlider.GetCalculatedTransformA();
                if (drawFrames)
                {
                    debugDraw.DrawTransform(ref tr, dbgDrawSize);
                }
                tr = pSlider.GetCalculatedTransformB();
                if (drawFrames)
                {
                    debugDraw.DrawTransform(ref tr, dbgDrawSize);
                }
                IndexedVector3 zero = IndexedVector3.Zero;
                if (drawLimits)
                {
                    IndexedMatrix  tr2    = pSlider.GetCalculatedTransformA();
                    IndexedVector3 li_min = tr2 * new IndexedVector3(pSlider.GetLowerLinLimit(), 0f, 0f);
                    IndexedVector3 li_max = tr2 * new IndexedVector3(pSlider.GetUpperLinLimit(), 0f, 0f);
                    debugDraw.DrawLine(ref li_min, ref li_max, ref zero);
                    IndexedVector3 normal = tr._basis.GetColumn(0);
                    IndexedVector3 axis   = tr._basis.GetColumn(1);
                    float          a_min  = pSlider.GetLowerAngLimit();
                    float          a_max  = pSlider.GetUpperAngLimit();
                    IndexedVector3 center = pSlider.GetCalculatedTransformB()._origin;
                    debugDraw.DrawArc(ref center, ref normal, ref axis, dbgDrawSize, dbgDrawSize, a_min, a_max, ref zero, true);
                }
            }
            break;

            default:
                break;
            }
            return;
        }
示例#2
0
        public override void InitializeDemo()
        {
            m_collisionConfiguration = new DefaultCollisionConfiguration();
            m_dispatcher             = new CollisionDispatcher(m_collisionConfiguration);
            IndexedVector3 worldMin = new IndexedVector3(-1000, -1000, -1000);
            IndexedVector3 worldMax = new IndexedVector3(1000, 1000, 1000);

            m_broadphase       = new AxisSweep3Internal(ref worldMin, ref worldMax, 0xfffe, 0xffff, 16384, null, false);
            m_constraintSolver = new SequentialImpulseConstraintSolver();
            m_dynamicsWorld    = new DiscreteDynamicsWorld(m_dispatcher, m_broadphase, m_constraintSolver, m_collisionConfiguration);
            m_dynamicsWorld.SetDebugDrawer(m_debugDraw);

            SetCameraDistance(26f);

            //CollisionShape groundShape = new BoxShape(new IndexedVector3(50f, 40f, 50f));
            CollisionShape groundShape = new StaticPlaneShape(new IndexedVector3(0, 1, 0), 40);

            m_collisionShapes.Add(groundShape);
            IndexedMatrix groundTransform = IndexedMatrix.Identity;

            groundTransform._origin = new IndexedVector3(0, -56, 0);
            RigidBody groundBody = LocalCreateRigidBody(0, ref groundTransform, groundShape);

            CollisionShape shape = new BoxShape(new IndexedVector3(CUBE_HALF_EXTENTS, CUBE_HALF_EXTENTS, CUBE_HALF_EXTENTS));

            m_collisionShapes.Add(shape);
            IndexedMatrix trans = IndexedMatrix.Identity;

            trans._origin = new IndexedVector3(0, 20, 0);

            float mass = 1f;

        #if true
            //point to point constraint (ball socket)
            //SEEMS OK
            {
                RigidBody body0 = LocalCreateRigidBody(mass, ref trans, shape);
                trans._origin = new IndexedVector3(2 * CUBE_HALF_EXTENTS, 20, 0);

                mass = 1f;
                RigidBody body1 = null;        //localCreateRigidBody( mass,trans,shape);

                IndexedVector3 pivotInA = new IndexedVector3(CUBE_HALF_EXTENTS, -CUBE_HALF_EXTENTS, -CUBE_HALF_EXTENTS);
                IndexedVector3 axisInA  = new IndexedVector3(0, 0, 1);

                IndexedVector3 pivotInB = body1 != null?body1.GetCenterOfMassTransform().Inverse() * (body0.GetCenterOfMassTransform() * (pivotInA)) : pivotInA;

                IndexedVector3 axisInB = body1 != null ? (body1.GetCenterOfMassTransform()._basis.Inverse() * (body1.GetCenterOfMassTransform()._basis *axisInA)) :
                                         body0.GetCenterOfMassTransform()._basis *axisInA;

                HingeConstraint hinge = new HingeConstraint(body0, ref pivotInA, ref axisInA, false);

                float targetVelocity  = 1f;
                float maxMotorImpulse = 1.0f;
                hinge.EnableAngularMotor(true, targetVelocity, maxMotorImpulse);

                m_dynamicsWorld.AddConstraint(hinge);        //p2p);
                hinge.SetDbgDrawSize(5f);
            }
        #endif

#if true
            //create a slider, using the generic D6 constraint
            // SEEMS OK
            {
                mass = 1f;
                IndexedVector3     sliderWorldPos    = new IndexedVector3(0, 10, 0);
                IndexedVector3     sliderAxis        = new IndexedVector3(1, 0, 0);
                float              angle             = 0f;//SIMD_RADS_PER_DEG * 10.f;
                IndexedBasisMatrix sliderOrientation = new IndexedBasisMatrix(Quaternion.CreateFromAxisAngle(sliderAxis.ToVector3(), angle));
                trans         = IndexedMatrix.Identity;
                trans._origin = sliderWorldPos;
                //trans.setBasis(sliderOrientation);
                sliderTransform = trans;

                d6body0 = LocalCreateRigidBody(mass, ref trans, shape);
                d6body0.SetActivationState(ActivationState.DISABLE_DEACTIVATION);
                RigidBody fixedBody1 = LocalCreateRigidBody(0, ref trans, null);
                m_dynamicsWorld.AddRigidBody(fixedBody1);

                IndexedMatrix frameInA, frameInB;
                frameInA         = IndexedMatrix.Identity;
                frameInB         = IndexedMatrix.Identity;
                frameInA._origin = new IndexedVector3(0, 5, 0);
                frameInB._origin = new IndexedVector3(0, 5, 0);

                //		bool useLinearReferenceFrameA = false;//use fixed frame B for linear llimits
                bool useLinearReferenceFrameA = true;        //use fixed frame A for linear llimits
                spSlider6Dof = new Generic6DofConstraint(fixedBody1, d6body0, ref frameInA, ref frameInB, useLinearReferenceFrameA);
                spSlider6Dof.SetLinearLowerLimit(ref lowerSliderLimit);
                spSlider6Dof.SetLinearUpperLimit(ref hiSliderLimit);

                //range should be small, otherwise singularities will 'explode' the constraint
                IndexedVector3 angularLower = new IndexedVector3(-1.5f, 0, 0);
                IndexedVector3 angularUpper = -angularLower;
                spSlider6Dof.SetAngularLowerLimit(ref angularLower);
                spSlider6Dof.SetAngularUpperLimit(ref angularUpper);
                //		slider.setAngularLowerLimit(IndexedVector3(0,0,0));
                //		slider.setAngularUpperLimit(IndexedVector3(0,0,0));

                spSlider6Dof.GetTranslationalLimitMotor().m_enableMotor[0] = true;
                spSlider6Dof.GetTranslationalLimitMotor().m_targetVelocity.X = -5.0f;
                spSlider6Dof.GetTranslationalLimitMotor().m_maxMotorForce.X = 0.1f;


                m_dynamicsWorld.AddConstraint(spSlider6Dof);
                spSlider6Dof.SetDbgDrawSize(5f);
            }
#endif
#if true
            {     // create a door using hinge constraint attached to the world
                CollisionShape pDoorShape = new BoxShape(new IndexedVector3(2.0f, 5.0f, 0.2f));
                m_collisionShapes.Add(pDoorShape);
                IndexedMatrix doorTrans = IndexedMatrix.Identity;
                doorTrans._origin = new IndexedVector3(-5.0f, -2.0f, 0.0f);
                RigidBody pDoorBody = LocalCreateRigidBody(1.0f, ref doorTrans, pDoorShape);
                pDoorBody.SetActivationState(ActivationState.DISABLE_DEACTIVATION);
                IndexedVector3 btPivotA = new IndexedVector3(10f + 2.1f, -2.0f, 0.0f);   // right next to the door slightly outside
                IndexedVector3 btAxisA  = new IndexedVector3(0.0f, 1.0f, 0.0f);          // pointing upwards, aka Y-axis

                spDoorHinge = new HingeConstraint(pDoorBody, ref btPivotA, ref btAxisA, false);

                spDoorHinge.SetLimit(-MathUtil.SIMD_PI * 0.25f, MathUtil.SIMD_PI * 0.25f);
                m_dynamicsWorld.AddConstraint(spDoorHinge);
                spDoorHinge.SetDbgDrawSize(5.0f);
            }
#endif
#if true
            { // create a generic 6DOF constraint
                // SEEMS OK - But debug draw a bit wrong?
                IndexedMatrix tr = IndexedMatrix.Identity;
                tr._origin = new IndexedVector3(10f, 6f, 0f);
                //tr.getBasis().setEulerZYX(0,0,0);
                //		RigidBody pBodyA = localCreateRigidBody( mass, tr, shape);
                RigidBody pBodyA = LocalCreateRigidBody(0.0f, ref tr, shape);
                //		RigidBody pBodyA = localCreateRigidBody( 0.0, tr, 0);
                pBodyA.SetActivationState(ActivationState.DISABLE_DEACTIVATION);

                tr         = IndexedMatrix.Identity;
                tr._origin = new IndexedVector3(0f, 6f, 0f);
                //tr.getBasis().setEulerZYX(0,0,0);
                RigidBody pBodyB = LocalCreateRigidBody(mass, ref tr, shape);
                pBodyB.SetActivationState(ActivationState.DISABLE_DEACTIVATION);

                IndexedMatrix frameInA, frameInB;
                frameInA = IndexedMatrix.CreateTranslation(-5, 0, 0);
                frameInB = IndexedMatrix.CreateTranslation(5, 0, 0);

                Generic6DofConstraint pGen6DOF = new Generic6DofConstraint(pBodyA, pBodyB, ref frameInA, ref frameInB, true);
                //		btGeneric6DofConstraint* pGen6DOF = new btGeneric6DofConstraint(*pBodyA, *pBodyB, frameInA, frameInB, false);
                IndexedVector3 linearLower = new IndexedVector3(-10, -2, -1);
                pGen6DOF.SetLinearLowerLimit(ref linearLower);
                IndexedVector3 linearUpper = new IndexedVector3(10, 2, 1);
                pGen6DOF.SetLinearUpperLimit(ref linearUpper);
                // ? why again?
                //linearLower = new IndexedVector3(-10,0,0);
                //pGen6DOF.setLinearLowerLimit(ref linearLower);
                //		pGen6DOF.setLinearUpperLimit(IndexedVector3(10., 0., 0.));
                //		pGen6DOF.setLinearLowerLimit(IndexedVector3(0., 0., 0.));
                //		pGen6DOF.setLinearUpperLimit(IndexedVector3(0., 0., 0.));

                //		pGen6DOF.getTranslationalLimitMotor().m_enableMotor[0] = true;
                //		pGen6DOF.getTranslationalLimitMotor().m_targetVelocity[0] = 5.0f;
                //		pGen6DOF.getTranslationalLimitMotor().m_maxMotorForce[0] = 0.1f;


                //		pGen6DOF.setAngularLowerLimit(IndexedVector3(0., SIMD_HALF_PI*0.9, 0.));
                //		pGen6DOF.setAngularUpperLimit(IndexedVector3(0., -SIMD_HALF_PI*0.9, 0.));
                //		pGen6DOF.setAngularLowerLimit(IndexedVector3(0., 0., -SIMD_HALF_PI));
                //		pGen6DOF.setAngularUpperLimit(IndexedVector3(0., 0., SIMD_HALF_PI));

                IndexedVector3 angularLower = new IndexedVector3(-MathUtil.SIMD_HALF_PI * 0.5f, -0.75f, -MathUtil.SIMD_HALF_PI * 0.8f);
                IndexedVector3 angularUpper = -angularLower;
                pGen6DOF.SetAngularLowerLimit(ref angularLower);
                pGen6DOF.SetAngularUpperLimit(ref angularUpper);
                //		pGen6DOF.setAngularLowerLimit(IndexedVector3(0.f, -0.75, SIMD_HALF_PI * 0.8f));
                //		pGen6DOF.setAngularUpperLimit(IndexedVector3(0.f, 0.75, -SIMD_HALF_PI * 0.8f));
                //		pGen6DOF.setAngularLowerLimit(IndexedVector3(0.f, -SIMD_HALF_PI * 0.8f, SIMD_HALF_PI * 1.98f));
                //		pGen6DOF.setAngularUpperLimit(IndexedVector3(0.f, SIMD_HALF_PI * 0.8f,  -SIMD_HALF_PI * 1.98f));



                //		pGen6DOF.setAngularLowerLimit(IndexedVector3(-0.75,-0.5, -0.5));
                //		pGen6DOF.setAngularUpperLimit(IndexedVector3(0.75,0.5, 0.5));
                //		pGen6DOF.setAngularLowerLimit(IndexedVector3(-0.75,0., 0.));
                //		pGen6DOF.setAngularUpperLimit(IndexedVector3(0.75,0., 0.));

                m_dynamicsWorld.AddConstraint(pGen6DOF, true);
                pGen6DOF.SetDbgDrawSize(5.0f);
            }
#endif
#if true
            { // create a ConeTwist constraint
                IndexedMatrix tr = IndexedMatrix.CreateTranslation(-10, 5, 0);

                RigidBody pBodyA = LocalCreateRigidBody(1.0f, ref tr, shape);
                pBodyA.SetActivationState(ActivationState.DISABLE_DEACTIVATION);

                tr = IndexedMatrix.CreateTranslation(-10, -5, 0);

                RigidBody pBodyB = LocalCreateRigidBody(0.0f, ref tr, shape);

                IndexedMatrix frameInA, frameInB;
                frameInA         = MathUtil.SetEulerZYX(0, 0, MathUtil.SIMD_HALF_PI);
                frameInA._origin = new IndexedVector3(0, -5, 0);
                frameInB         = MathUtil.SetEulerZYX(0, 0, MathUtil.SIMD_HALF_PI);
                frameInB._origin = new IndexedVector3(0, 5, 0);

                ConeTwistConstraint pCT = new ConeTwistConstraint(pBodyA, pBodyB, ref frameInA, ref frameInB);
                pCT.SetLimit(MathUtil.SIMD_QUARTER_PI, MathUtil.SIMD_QUARTER_PI, MathUtil.SIMD_PI * 0.8f, 1.0f, 0.3f, 1.0f);       // soft limit == hard limit
                m_dynamicsWorld.AddConstraint(pCT, true);
                pCT.SetDbgDrawSize(5.0f);
            }
#endif
#if true
            { // Hinge connected to the world, with motor (to hinge motor with new and old constraint solver)
                // WORKS OK
                IndexedMatrix tr    = IndexedMatrix.Identity;
                RigidBody     pBody = LocalCreateRigidBody(1.0f, ref tr, shape);
                pBody.SetActivationState(ActivationState.DISABLE_DEACTIVATION);
                IndexedVector3 btPivotA = new IndexedVector3(10.0f, 0.0f, 0.0f);
                IndexedVector3 btAxisA  = new IndexedVector3(0.0f, 0.0f, 1.0f);

                HingeConstraint pHinge = new HingeConstraint(pBody, ref btPivotA, ref btAxisA, false);
                //		pHinge.enableAngularMotor(true, -1.0, 0.165); // use for the old solver
                pHinge.EnableAngularMotor(true, -1.0f, 1.65f);         // use for the new SIMD solver
                m_dynamicsWorld.AddConstraint(pHinge);
                pHinge.SetDbgDrawSize(5.0f);
            }
#endif
#if true
            {
                // WORKS OK
                // create a universal joint using generic 6DOF constraint
                // create two rigid bodies
                // static bodyA (parent) on top:
                IndexedMatrix tr     = IndexedMatrix.CreateTranslation(20, 4, 0);
                RigidBody     pBodyA = LocalCreateRigidBody(0.0f, ref tr, shape);
                pBodyA.SetActivationState(ActivationState.DISABLE_DEACTIVATION);
                // dynamic bodyB (child) below it :
                tr = IndexedMatrix.CreateTranslation(20, 0, 0);
                RigidBody pBodyB = LocalCreateRigidBody(1.0f, ref tr, shape);
                pBodyB.SetActivationState(ActivationState.DISABLE_DEACTIVATION);
                // add some (arbitrary) data to build constraint frames
                IndexedVector3 parentAxis = new IndexedVector3(1.0f, 0.0f, 0.0f);
                IndexedVector3 childAxis  = new IndexedVector3(0.0f, 0.0f, 1.0f);
                IndexedVector3 anchor     = new IndexedVector3(20.0f, 2.0f, 0.0f);

                UniversalConstraint pUniv = new UniversalConstraint(pBodyA, pBodyB, ref anchor, ref parentAxis, ref childAxis);
                pUniv.SetLowerLimit(-MathUtil.SIMD_HALF_PI * 0.5f, -MathUtil.SIMD_HALF_PI * 0.5f);
                pUniv.SetUpperLimit(MathUtil.SIMD_HALF_PI * 0.5f, MathUtil.SIMD_HALF_PI * 0.5f);
                // add constraint to world
                m_dynamicsWorld.AddConstraint(pUniv, true);
                // draw constraint frames and limits for debugging
                pUniv.SetDbgDrawSize(5.0f);
            }
#endif

#if true
            // WORKS OK
            { // create a generic 6DOF constraint with springs
                IndexedMatrix tr = IndexedMatrix.CreateTranslation(-20f, 16f, 0f);
                //tr.setIdentity();
                //tr.setOrigin(btVector3(btScalar(-20.), btScalar(16.), btScalar(0.)));
                //tr.getBasis().setEulerZYX(0,0,0);
                RigidBody pBodyA = LocalCreateRigidBody(0.0f, ref tr, shape);
                pBodyA.SetActivationState(ActivationState.DISABLE_DEACTIVATION);

                //tr.setIdentity();
                //tr.setOrigin(btVector3(btScalar(-10.), btScalar(16.), btScalar(0.)));
                //tr.getBasis().setEulerZYX(0,0,0);
                tr = IndexedMatrix.CreateTranslation(-10, 16, 0);
                RigidBody pBodyB = LocalCreateRigidBody(1.0f, ref tr, shape);
                pBodyB.SetActivationState(ActivationState.DISABLE_DEACTIVATION);

                IndexedMatrix frameInA = IndexedMatrix.CreateTranslation(10f, 0f, 0f);
                IndexedMatrix frameInB = IndexedMatrix.CreateTranslation(0f, 0f, 0f);

                Generic6DofSpringConstraint pGen6DOFSpring = new Generic6DofSpringConstraint(pBodyA, pBodyB, ref frameInA, ref frameInB, true);
                pGen6DOFSpring.SetLinearUpperLimit(new IndexedVector3(5f, 0f, 0f));
                pGen6DOFSpring.SetLinearLowerLimit(new IndexedVector3(-5f, 0f, 0f));

                pGen6DOFSpring.SetAngularLowerLimit(new IndexedVector3(0f, 0f, -1.5f));
                pGen6DOFSpring.SetAngularUpperLimit(new IndexedVector3(0f, 0f, 1.5f));

                m_dynamicsWorld.AddConstraint(pGen6DOFSpring, true);
                pGen6DOFSpring.SetDbgDrawSize(5.0f);

                pGen6DOFSpring.EnableSpring(0, true);
                pGen6DOFSpring.SetStiffness(0, 39.478f);
                pGen6DOFSpring.SetDamping(0, 0.5f);
                pGen6DOFSpring.EnableSpring(5, true);
                pGen6DOFSpring.SetStiffness(5, 39.478f);
                pGen6DOFSpring.SetDamping(0, 0.3f);
                pGen6DOFSpring.SetEquilibriumPoint();
            }
#endif
#if true
            {
                // WORKS OK
                // create a Hinge2 joint
                // create two rigid bodies
                // static bodyA (parent) on top:
                IndexedMatrix tr = IndexedMatrix.CreateTranslation(-20f, 4f, 0f);

                RigidBody pBodyA = LocalCreateRigidBody(0.0f, ref tr, shape);
                pBodyA.SetActivationState(ActivationState.DISABLE_DEACTIVATION);
                // dynamic bodyB (child) below it :
                tr = IndexedMatrix.CreateTranslation(-20f, 0f, 0f);
                RigidBody pBodyB = LocalCreateRigidBody(1.0f, ref tr, shape);
                pBodyB.SetActivationState(ActivationState.DISABLE_DEACTIVATION);
                // add some data to build constraint frames
                IndexedVector3   parentAxis = new IndexedVector3(0.0f, 1.0f, 0.0f);
                IndexedVector3   childAxis  = new IndexedVector3(1.0f, 0.0f, 0.0f);
                IndexedVector3   anchor     = new IndexedVector3(-20.0f, 0.0f, 0.0f);
                Hinge2Constraint pHinge2    = new Hinge2Constraint(pBodyA, pBodyB, ref anchor, ref parentAxis, ref childAxis);
                pHinge2.SetLowerLimit(-MathUtil.SIMD_HALF_PI * 0.5f);
                pHinge2.SetUpperLimit(MathUtil.SIMD_HALF_PI * 0.5f);
                // add constraint to world
                m_dynamicsWorld.AddConstraint(pHinge2, true);
                // draw constraint frames and limits for debugging
                pHinge2.SetDbgDrawSize(5.0f);
            }
#endif
#if true
            {
                // WORKS OK
                // create a Hinge joint between two dynamic bodies
                // create two rigid bodies
                // static bodyA (parent) on top:
                IndexedMatrix tr     = IndexedMatrix.CreateTranslation(-20f, -2f, 0f);
                RigidBody     pBodyA = LocalCreateRigidBody(1.0f, ref tr, shape);
                pBodyA.SetActivationState(ActivationState.DISABLE_DEACTIVATION);
                // dynamic bodyB:
                tr = IndexedMatrix.CreateTranslation(-30f, -2f, 0f);
                RigidBody pBodyB = LocalCreateRigidBody(10.0f, ref tr, shape);
                pBodyB.SetActivationState(ActivationState.DISABLE_DEACTIVATION);
                // add some data to build constraint frames
                IndexedVector3 axisA  = new IndexedVector3(0.0f, 1.0f, 0.0f);
                IndexedVector3 axisB  = new IndexedVector3(0.0f, 1.0f, 0.0f);
                IndexedVector3 pivotA = new IndexedVector3(-5.0f, 0.0f, 0.0f);
                IndexedVector3 pivotB = new IndexedVector3(5.0f, 0.0f, 0.0f);

                spHingeDynAB = new HingeConstraint(pBodyA, pBodyB, ref pivotA, ref pivotB, ref axisA, ref axisB);
                spHingeDynAB.SetLimit(-MathUtil.SIMD_HALF_PI * 0.5f, MathUtil.SIMD_HALF_PI * 0.5f);
                // add constraint to world
                m_dynamicsWorld.AddConstraint(spHingeDynAB, true);
                // draw constraint frames and limits for debugging
                spHingeDynAB.SetDbgDrawSize(5.0f);
            }
#endif
        }