Esempio n. 1
0
        internal void SolveTOI(ref TimeStep subStep)
        {
            _contactSolver.Reset(_contacts, ContactCount, subStep.dtRatio, false);

            // Solve position constraints.
            const float kTOIBaumgarte = 0.75f;
            for (int i = 0; i < Settings.TOIPositionIterations; ++i)
            {
                bool contactsOkay = _contactSolver.SolvePositionConstraints(kTOIBaumgarte);
                if (contactsOkay)
                {
                    break;
                }

                if (i == Settings.TOIPositionIterations - 1)
                {
                    i += 0;
                }
            }

            // Leap of faith to new safe state.
            for (int i = 0; i < BodyCount; ++i)
            {
                PhysicsBody body = Bodies[i];
                body.Sweep.A0 = body.Sweep.A;
                body.Sweep.C0 = body.Sweep.C;
            }

            // No warm starting is needed for TOI events because warm
            // starting impulses were applied in the discrete solver.
            _contactSolver.InitializeVelocityConstraints();

            // Solve velocity constraints.
            for (int i = 0; i < Settings.TOIVelocityIterations; ++i)
            {
                _contactSolver.SolveVelocityConstraints();
            }

            // Don't store the TOI contact forces for warm starting
            // because they can be quite large.

            // Integrate positions.
            for (int i = 0; i < BodyCount; ++i)
            {
                PhysicsBody b = Bodies[i];

                if (b.BodyType == BodyType.Static)
                {
                    continue;
                }

                // Check for large velocities.
                float translationx = subStep.dt * b.LinearVelocityInternal.X;
                float translationy = subStep.dt * b.LinearVelocityInternal.Y;
                float dot = translationx * translationx + translationy * translationy;
                if (dot > Settings.MaxTranslationSquared)
                {
                    float norm = 1f / (float)Math.Sqrt(dot);
                    float value = Settings.MaxTranslation * subStep.inv_dt;
                    b.LinearVelocityInternal.X = value * (translationx * norm);
                    b.LinearVelocityInternal.Y = value * (translationy * norm);
                }

                float rotation = subStep.dt * b.AngularVelocity;
                if (rotation * rotation > Settings.MaxRotationSquared)
                {
                    if (rotation < 0.0)
                    {
                        b.AngularVelocityInternal = -subStep.inv_dt * Settings.MaxRotation;
                    }
                    else
                    {
                        b.AngularVelocityInternal = subStep.inv_dt * Settings.MaxRotation;
                    }
                }

                // Integrate
                b.Sweep.C.X += subStep.dt * b.LinearVelocityInternal.X;
                b.Sweep.C.Y += subStep.dt * b.LinearVelocityInternal.Y;
                b.Sweep.A += subStep.dt * b.AngularVelocityInternal;

                // Compute new transform
                b.SynchronizeTransform();

                // Note: shapes are synchronized later.
            }

            Report(_contactSolver.Constraints);
        }
Esempio n. 2
0
        /// <summary>
        /// Find TOI contacts and solve them.
        /// </summary>
        /// <param name="step">The step.</param>
        private void SolveTOI(ref TimeStep step)
        {
            Island.Reset(2 * Settings.MaxTOIContacts, Settings.MaxTOIContacts, 0, ContactManager);

            if (_stepComplete)
            {
                for (int i = 0; i < BodyList.Count; i++)
                {
                    BodyList[i].Flags &= ~BodyFlags.Island;
                    BodyList[i].Sweep.Alpha0 = 0.0f;
                }

                for (int i = 0; i < ContactManager.ContactList.Count; i++)
                {
                    Contact c = ContactManager.ContactList[i];

                    // Invalidate TOI
                    c.Flags &= ~(ContactFlags.TOI | ContactFlags.Island);
                    c.TOICount = 0;
                    c.TOI = 1.0f;
                }
            }

            // Find TOI events and solve them.
            for (; ; )
            {
                // Find the first TOI.
                Contact minContact = null;
                float minAlpha = 1.0f;

                for (int i = 0; i < ContactManager.ContactList.Count; i++)
                {
                    Contact c = ContactManager.ContactList[i];

                    // Is this contact disabled?
                    if (c.Enabled == false)
                    {
                        continue;
                    }

                    // Prevent excessive sub-stepping.
                    if (c.TOICount > Settings.MaxSubSteps)
                    {
                        continue;
                    }

                    float alpha;
                    if ((c.Flags & ContactFlags.TOI) == ContactFlags.TOI)
                    {
                        // This contact has a valid cached TOI.
                        alpha = c.TOI;
                    }
                    else
                    {
                        Fixture fA = c.FixtureA;
                        Fixture fB = c.FixtureB;

                        // Is there a sensor?
                        if (fA.IsSensor || fB.IsSensor)
                        {
                            continue;
                        }

                        PhysicsBody bA = fA.Body;
                        PhysicsBody bB = fB.Body;

                        BodyType typeA = bA.BodyType;
                        BodyType typeB = bB.BodyType;

                        bool awakeA = bA.Awake && typeA != BodyType.Static;
                        bool awakeB = bB.Awake && typeB != BodyType.Static;

                        // Is at least one body awake?
                        if (awakeA == false && awakeB == false)
                        {
                            continue;
                        }

                        bool collideA = (bA.IsBullet || typeA != BodyType.Dynamic) && !bA.IgnoreCCD;
                        bool collideB = (bB.IsBullet || typeB != BodyType.Dynamic) && !bB.IgnoreCCD;

                        // Are these two non-bullet dynamic bodies?
                        if (collideA == false && collideB == false)
                        {
                            continue;
                        }

                        // Compute the TOI for this contact.
                        // Put the sweeps onto the same time interval.
                        float alpha0 = bA.Sweep.Alpha0;

                        if (bA.Sweep.Alpha0 < bB.Sweep.Alpha0)
                        {
                            alpha0 = bB.Sweep.Alpha0;
                            bA.Sweep.Advance(alpha0);
                        }
                        else if (bB.Sweep.Alpha0 < bA.Sweep.Alpha0)
                        {
                            alpha0 = bA.Sweep.Alpha0;
                            bB.Sweep.Advance(alpha0);
                        }

                        Debug.Assert(alpha0 < 1.0f);

                        // Compute the time of impact in interval [0, minTOI]
                        _input.ProxyA.Set(fA.Shape, c.ChildIndexA);
                        _input.ProxyB.Set(fB.Shape, c.ChildIndexB);
                        _input.SweepA = bA.Sweep;
                        _input.SweepB = bB.Sweep;
                        _input.TMax = 1.0f;

                        TOIOutput output;
                        TimeOfImpact.CalculateTimeOfImpact(out output, _input);

                        // Beta is the fraction of the remaining portion of the .
                        float beta = output.T;
                        if (output.State == TOIOutputState.Touching)
                        {
                            alpha = Math.Min(alpha0 + (1.0f - alpha0) * beta, 1.0f);
                        }
                        else
                        {
                            alpha = 1.0f;
                        }

                        c.TOI = alpha;
                        c.Flags |= ContactFlags.TOI;
                    }

                    if (alpha < minAlpha)
                    {
                        // This is the minimum TOI found so far.
                        minContact = c;
                        minAlpha = alpha;
                    }
                }

                if (minContact == null || 1.0f - 10.0f * Settings.Epsilon < minAlpha)
                {
                    // No more TOI events. Done!
                    _stepComplete = true;
                    break;
                }

                // Advance the bodies to the TOI.
                Fixture fA1 = minContact.FixtureA;
                Fixture fB1 = minContact.FixtureB;
                PhysicsBody bA1 = fA1.Body;
                PhysicsBody bB1 = fB1.Body;

                Sweep backup1 = bA1.Sweep;
                Sweep backup2 = bB1.Sweep;

                bA1.Advance(minAlpha);
                bB1.Advance(minAlpha);

                // The TOI contact likely has some new contact points.
                minContact.Update(ContactManager);
                minContact.Flags &= ~ContactFlags.TOI;
                ++minContact.TOICount;

                // Is the contact solid?
                if (minContact.Enabled == false || minContact.IsTouching() == false)
                {
                    // Restore the sweeps.
                    minContact.Enabled = false;
                    bA1.Sweep = backup1;
                    bB1.Sweep = backup2;
                    bA1.SynchronizeTransform();
                    bB1.SynchronizeTransform();
                    continue;
                }

                bA1.Awake = true;
                bB1.Awake = true;

                // Build the island
                Island.Clear();
                Island.Add(bA1);
                Island.Add(bB1);
                Island.Add(minContact);

                bA1.Flags |= BodyFlags.Island;
                bB1.Flags |= BodyFlags.Island;
                minContact.Flags |= ContactFlags.Island;

                // Get contacts on bodyA and bodyB.
                PhysicsBody[] bodies = { bA1, bB1 };
                for (int i = 0; i < 2; ++i)
                {
                    PhysicsBody body = bodies[i];
                    if (body.BodyType == BodyType.Dynamic)
                    {
                        // for (ContactEdge ce = body.ContactList; ce && Island.BodyCount < Settings.MaxTOIContacts; ce = ce.Next)
                        for (ContactEdge ce = body.ContactList; ce != null; ce = ce.Next)
                        {
                            Contact contact = ce.Contact;

                            // Has this contact already been added to the island?
                            if ((contact.Flags & ContactFlags.Island) == ContactFlags.Island)
                            {
                                continue;
                            }

                            // Only add static, kinematic, or bullet bodies.
                            PhysicsBody other = ce.Other;
                            if (other.BodyType == BodyType.Dynamic &&
                                body.IsBullet == false && other.IsBullet == false)
                            {
                                continue;
                            }

                            // Skip sensors.
                            if (contact.FixtureA.IsSensor || contact.FixtureB.IsSensor)
                            {
                                continue;
                            }

                            // Tentatively advance the body to the TOI.
                            Sweep backup = other.Sweep;
                            if ((other.Flags & BodyFlags.Island) == 0)
                            {
                                other.Advance(minAlpha);
                            }

                            // Update the contact points
                            contact.Update(ContactManager);

                            // Was the contact disabled by the user?
                            if (contact.Enabled == false)
                            {
                                other.Sweep = backup;
                                other.SynchronizeTransform();
                                continue;
                            }

                            // Are there contact points?
                            if (contact.IsTouching() == false)
                            {
                                other.Sweep = backup;
                                other.SynchronizeTransform();
                                continue;
                            }

                            // Add the contact to the island
                            contact.Flags |= ContactFlags.Island;
                            Island.Add(contact);

                            // Has the other body already been added to the island?
                            if ((other.Flags & BodyFlags.Island) == BodyFlags.Island)
                            {
                                continue;
                            }

                            // Add the other body to the island.
                            other.Flags |= BodyFlags.Island;

                            if (other.BodyType != BodyType.Static)
                            {
                                other.Awake = true;
                            }

                            Island.Add(other);
                        }
                    }
                }

                TimeStep subStep;
                subStep.dt = (1.0f - minAlpha) * step.dt;
                subStep.inv_dt = 1.0f / subStep.dt;
                subStep.dtRatio = 1.0f;

                //subStep.positionIterations = 20;
                //subStep.velocityIterations = step.velocityIterations;
                //subStep.warmStarting = false;
                Island.SolveTOI(ref subStep);

                // Reset island flags and synchronize broad-phase proxies.
                for (int i = 0; i < Island.BodyCount; ++i)
                {
                    PhysicsBody body = Island.Bodies[i];
                    body.Flags &= ~BodyFlags.Island;

                    if (body.BodyType != BodyType.Dynamic)
                    {
                        continue;
                    }

                    body.SynchronizeFixtures();

                    // Invalidate all contact TOIs on this displaced body.
                    for (ContactEdge ce = body.ContactList; ce != null; ce = ce.Next)
                    {
                        ce.Contact.Flags &= ~(ContactFlags.TOI | ContactFlags.Island);
                    }
                }

                // Commit fixture proxy movements to the broad-phase so that new contacts are created.
                // Also, some contacts can be destroyed.
                ContactManager.FindNewContacts();

                if (EnableSubStepping)
                {
                    _stepComplete = false;
                    break;
                }
            }
        }
Esempio n. 3
0
        public void Solve(ref TimeStep step, ref Vector2 gravity)
        {
            // Integrate velocities and apply damping.
            for (int i = 0; i < BodyCount; ++i)
            {
                PhysicsBody b = Bodies[i];

                if (b.BodyType != BodyType.Dynamic)
                {
                    continue;
                }

                // Integrate velocities.
                // FPE 3 only - Only apply gravity if the body wants it.
                if (b.IgnoreGravity)
                {
                    b.LinearVelocityInternal.X += step.dt * (b.InvMass * b.Force.X);
                    b.LinearVelocityInternal.Y += step.dt * (b.InvMass * b.Force.Y);
                    b.AngularVelocityInternal += step.dt * b.InvI * b.Torque;
                }
                else
                {
                    b.LinearVelocityInternal.X += step.dt * (gravity.X + b.InvMass * b.Force.X);
                    b.LinearVelocityInternal.Y += step.dt * (gravity.Y + b.InvMass * b.Force.Y);
                    b.AngularVelocityInternal += step.dt * b.InvI * b.Torque;
                }

                // Apply damping.
                // ODE: dv/dt + c * v = 0
                // Solution: v(t) = v0 * exp(-c * t)
                // Time step: v(t + dt) = v0 * exp(-c * (t + dt)) = v0 * exp(-c * t) * exp(-c * dt) = v * exp(-c * dt)
                // v2 = exp(-c * dt) * v1
                // Taylor expansion:
                // v2 = (1.0f - c * dt) * v1
                b.LinearVelocityInternal *= MathUtils.Clamp(1.0f - step.dt * b.LinearDamping, 0.0f, 1.0f);
                b.AngularVelocityInternal *= MathUtils.Clamp(1.0f - step.dt * b.AngularDamping, 0.0f, 1.0f);
            }

            // Partition contacts so that contacts with static bodies are solved last.
            int i1 = -1;
            for (int i2 = 0; i2 < ContactCount; ++i2)
            {
                Fixture fixtureA = _contacts[i2].FixtureA;
                Fixture fixtureB = _contacts[i2].FixtureB;
                PhysicsBody bodyA = fixtureA.Body;
                PhysicsBody bodyB = fixtureB.Body;
                bool nonStatic = bodyA.BodyType != BodyType.Static && bodyB.BodyType != BodyType.Static;
                if (nonStatic)
                {
                    ++i1;

                    //TODO: Only swap if they are not the same? see http://code.google.com/p/box2d/issues/detail?id=162
                    Contact tmp = _contacts[i1];
                    _contacts[i1] = _contacts[i2];
                    _contacts[i2] = tmp;
                }
            }

            // Initialize velocity constraints.
            _contactSolver.Reset(_contacts, ContactCount, step.dtRatio, Settings.EnableWarmstarting);
            _contactSolver.InitializeVelocityConstraints();

            if (Settings.EnableWarmstarting)
            {
                _contactSolver.WarmStart();
            }

            #if (!SILVERLIGHT)
            if (Settings.EnableDiagnostics)
            {
                _watch.Start();
                _tmpTime = 0;
            }
            #endif

            for (int i = 0; i < JointCount; ++i)
            {
                if (_joints[i].Enabled)
                    _joints[i].InitVelocityConstraints(ref step);
            }

            #if (!SILVERLIGHT)
            if (Settings.EnableDiagnostics)
            {
                _tmpTime += _watch.ElapsedTicks;
            }
            #endif

            // Solve velocity constraints.
            for (int i = 0; i < Settings.VelocityIterations; ++i)
            {
            #if (!SILVERLIGHT)
                if (Settings.EnableDiagnostics)
                    _watch.Start();
            #endif
                for (int j = 0; j < JointCount; ++j)
                {
                    PhysicsJoint joint = _joints[j];

                    if (!joint.Enabled)
                        continue;

                    joint.SolveVelocityConstraints(ref step);
                    joint.Validate(step.inv_dt);
                }

            #if (!SILVERLIGHT)
                if (Settings.EnableDiagnostics)
                {
                    _watch.Stop();
                    _tmpTime += _watch.ElapsedTicks;
                    _watch.Reset();
                }
            #endif

                _contactSolver.SolveVelocityConstraints();
            }

            // Post-solve (store impulses for warm starting).
            _contactSolver.StoreImpulses();

            // Integrate positions.
            for (int i = 0; i < BodyCount; ++i)
            {
                PhysicsBody b = Bodies[i];

                if (b.BodyType == BodyType.Static)
                {
                    continue;
                }

                // Check for large velocities.
                float translationX = step.dt * b.LinearVelocityInternal.X;
                float translationY = step.dt * b.LinearVelocityInternal.Y;
                float result = translationX * translationX + translationY * translationY;

                if (result > Settings.MaxTranslationSquared)
                {
                    float sq = (float)Math.Sqrt(result);

                    float ratio = Settings.MaxTranslation / sq;
                    b.LinearVelocityInternal.X *= ratio;
                    b.LinearVelocityInternal.Y *= ratio;
                }

                float rotation = step.dt * b.AngularVelocityInternal;
                if (rotation * rotation > Settings.MaxRotationSquared)
                {
                    float ratio = Settings.MaxRotation / Math.Abs(rotation);
                    b.AngularVelocityInternal *= ratio;
                }

                // Store positions for continuous collision.
                b.Sweep.C0.X = b.Sweep.C.X;
                b.Sweep.C0.Y = b.Sweep.C.Y;
                b.Sweep.A0 = b.Sweep.A;

                // Integrate
                b.Sweep.C.X += step.dt * b.LinearVelocityInternal.X;
                b.Sweep.C.Y += step.dt * b.LinearVelocityInternal.Y;
                b.Sweep.A += step.dt * b.AngularVelocityInternal;

                // Compute new transform
                b.SynchronizeTransform();

                // Note: shapes are synchronized later.
            }

            // Iterate over constraints.
            for (int i = 0; i < Settings.PositionIterations; ++i)
            {
                bool contactsOkay = _contactSolver.SolvePositionConstraints(Settings.ContactBaumgarte);
                bool jointsOkay = true;

            #if (!SILVERLIGHT)
                if (Settings.EnableDiagnostics)
                    _watch.Start();
            #endif
                for (int j = 0; j < JointCount; ++j)
                {
                    PhysicsJoint joint = _joints[j];
                    if (!joint.Enabled)
                        continue;

                    bool jointOkay = joint.SolvePositionConstraints();
                    jointsOkay = jointsOkay && jointOkay;
                }

            #if (!SILVERLIGHT)
                if (Settings.EnableDiagnostics)
                {
                    _watch.Stop();
                    _tmpTime += _watch.ElapsedTicks;
                    _watch.Reset();
                }
            #endif
                if (contactsOkay && jointsOkay)
                {
                    // Exit early if the position errors are small.
                    break;
                }
            }

            #if (!SILVERLIGHT)
            if (Settings.EnableDiagnostics)
            {
                JointUpdateTime = _tmpTime;
            }
            #endif

            Report(_contactSolver.Constraints);

            if (Settings.AllowSleep)
            {
                float minSleepTime = Settings.MaxFloat;

                for (int i = 0; i < BodyCount; ++i)
                {
                    PhysicsBody b = Bodies[i];
                    if (b.BodyType == BodyType.Static)
                    {
                        continue;
                    }

                    if ((b.Flags & BodyFlags.AutoSleep) == 0)
                    {
                        b.SleepTime = 0.0f;
                        minSleepTime = 0.0f;
                    }

                    if ((b.Flags & BodyFlags.AutoSleep) == 0 ||
                        b.AngularVelocityInternal * b.AngularVelocityInternal > AngTolSqr ||
                        Vector2.Dot(b.LinearVelocityInternal, b.LinearVelocityInternal) > LinTolSqr)
                    {
                        b.SleepTime = 0.0f;
                        minSleepTime = 0.0f;
                    }
                    else
                    {
                        b.SleepTime += step.dt;
                        minSleepTime = Math.Min(minSleepTime, b.SleepTime);
                    }
                }

                if (minSleepTime >= Settings.TimeToSleep)
                {
                    for (int i = 0; i < BodyCount; ++i)
                    {
                        PhysicsBody b = Bodies[i];
                        b.Awake = false;
                    }
                }
            }
        }
Esempio n. 4
0
        private void Solve(ref TimeStep step)
        {
            // Size the island for the worst case.
            Island.Reset(BodyList.Count,
                         ContactManager.ContactList.Count,
                         JointList.Count,
                         ContactManager);

            // Clear all the island flags.
            foreach (PhysicsBody b in BodyList)
            {
                b.Flags &= ~BodyFlags.Island;
            }

            for (int i = 0; i < ContactManager.ContactList.Count; i++)
            {
                Contact c = ContactManager.ContactList[i];
                c.Flags &= ~ContactFlags.Island;
            }
            foreach (PhysicsJoint j in JointList)
            {
                j.IslandFlag = false;
            }

            // Build and simulate all awake islands.
            int stackSize = BodyList.Count;
            if (stackSize > _stack.Length)
                _stack = new PhysicsBody[Math.Max(_stack.Length * 2, stackSize)];

            for (int index = BodyList.Count - 1; index >= 0; index--)
            {
                PhysicsBody seed = BodyList[index];
                if ((seed.Flags & (BodyFlags.Island)) != BodyFlags.None)
                {
                    continue;
                }

                if (seed.Awake == false || seed.Enabled == false)
                {
                    continue;
                }

                // The seed can be dynamic or kinematic.
                if (seed.BodyType == BodyType.Static)
                {
                    continue;
                }

                // Reset island and stack.
                Island.Clear();
                int stackCount = 0;
                _stack[stackCount++] = seed;
                seed.Flags |= BodyFlags.Island;

                // Perform a depth first search (DFS) on the constraint graph.
                while (stackCount > 0)
                {
                    // Grab the next body off the stack and add it to the island.
                    PhysicsBody b = _stack[--stackCount];
                    Debug.Assert(b.Enabled);
                    Island.Add(b);

                    // Make sure the body is awake.
                    b.Awake = true;

                    // To keep islands as small as possible, we don't
                    // propagate islands across static bodies.
                    if (b.BodyType == BodyType.Static)
                    {
                        continue;
                    }

                    // Search all contacts connected to this body.
                    for (ContactEdge ce = b.ContactList; ce != null; ce = ce.Next)
                    {
                        Contact contact = ce.Contact;

                        // Has this contact already been added to an island?
                        if ((contact.Flags & ContactFlags.Island) != ContactFlags.None)
                        {
                            continue;
                        }

                        // Is this contact solid and touching?
                        if (!ce.Contact.Enabled || !ce.Contact.IsTouching())
                        {
                            continue;
                        }

                        // Skip sensors.
                        bool sensorA = contact.FixtureA.IsSensor;
                        bool sensorB = contact.FixtureB.IsSensor;
                        if (sensorA || sensorB)
                        {
                            continue;
                        }

                        Island.Add(contact);
                        contact.Flags |= ContactFlags.Island;

                        PhysicsBody other = ce.Other;

                        // Was the other body already added to this island?
                        if ((other.Flags & BodyFlags.Island) != BodyFlags.None)
                        {
                            continue;
                        }

                        Debug.Assert(stackCount < stackSize);
                        _stack[stackCount++] = other;
                        other.Flags |= BodyFlags.Island;
                    }

                    // Search all joints connect to this body.
                    for (JointEdge je = b.JointList; je != null; je = je.Next)
                    {
                        if (je.Joint.IslandFlag)
                        {
                            continue;
                        }

                        PhysicsBody other = je.Other;

                        // WIP David
                        //Enter here when it's a non-fixed joint. Non-fixed joints have a other body.
                        if (other != null)
                        {
                            // Don't simulate joints connected to inactive bodies.
                            if (other.Enabled == false)
                            {
                                continue;
                            }

                            Island.Add(je.Joint);
                            je.Joint.IslandFlag = true;

                            if ((other.Flags & BodyFlags.Island) != BodyFlags.None)
                            {
                                continue;
                            }

                            Debug.Assert(stackCount < stackSize);
                            _stack[stackCount++] = other;
                            other.Flags |= BodyFlags.Island;
                        }
                        else
                        {
                            Island.Add(je.Joint);
                            je.Joint.IslandFlag = true;
                        }
                    }
                }

                Island.Solve(ref step, ref Gravity);

                // Post solve cleanup.
                for (int i = 0; i < Island.BodyCount; ++i)
                {
                    // Allow static bodies to participate in other islands.
                    PhysicsBody b = Island.Bodies[i];
                    if (b.BodyType == BodyType.Static)
                    {
                        b.Flags &= ~BodyFlags.Island;
                    }
                }
            }

            // Synchronize fixtures, check for out of range bodies.
            foreach (PhysicsBody b in BodyList)
            {
                // If a body was not in an island then it did not move.
                if ((b.Flags & BodyFlags.Island) != BodyFlags.Island)
                {
                    continue;
                }

                if (b.BodyType == BodyType.Static)
                {
                    continue;
                }

                // Update fixtures (for broad-phase).
                b.SynchronizeFixtures();
            }

            // Look for new contacts.
            ContactManager.FindNewContacts();
        }