public void Solve(Profile profile, TimeStep step, Vec2 gravity, bool allowSleep) { Timer timer = new Timer(); float h = step.dt; // Integrate velocities and apply damping. Initialize the body state. for (int i = 0; i < m_bodies.Count(); i++) { Body b = m_bodies[i]; Vec2 c = b.m_sweep.c; float a = b.m_sweep.a; Vec2 v = b.m_linearVelocity; float w = b.m_angularVelocity; // Store positions for continuous collision. b.m_sweep.c0 = b.m_sweep.c; b.m_sweep.a0 = b.m_sweep.a; if (b.m_type == BodyType._dynamicBody) { // Integrate velocities. v += h * (b.m_gravityScale * gravity + b.m_invMass * b.m_force); w += h * b.m_invI * b.m_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 v *= Utilities.Clamp(1.0f - h * b.m_linearDamping, 0.0f, 1.0f); w *= Utilities.Clamp(1.0f - h * b.m_angularDamping, 0.0f, 1.0f); } Position pos = new Position(); pos.c = c; pos.a = a; m_positions.Add(pos); Velocity vel = new Velocity(); vel.v = v; vel.w = w; m_velocities.Add(vel); } timer.Reset(); // Solver data SolverData solverData; solverData.step = step; solverData.positions = m_positions; solverData.velocities = m_velocities; // Initialize velocity constraints. ContactSolverDef contactSolverDef; contactSolverDef.step = step; contactSolverDef.contacts = m_contacts; contactSolverDef.positions = m_positions; contactSolverDef.velocities = m_velocities; ContactSolver contactSolver = new ContactSolver(contactSolverDef); contactSolver.InitializeVelocityConstraints(); if (step.warmStarting) { contactSolver.WarmStart(); } for (int i = 0; i < m_joints.Count(); ++i) { m_joints[i].InitVelocityConstraints(solverData); } profile.solveInit = timer.GetMilliseconds(); // Solve velocity constraints timer.Reset(); for (int i = 0; i < step.velocityIterations; ++i) { for (int j = 0; j < m_joints.Count(); ++j) { m_joints[j].SolveVelocityConstraints(solverData); } contactSolver.SolveVelocityConstraints(); } // Store impulses for warm starting contactSolver.StoreImpulses(); profile.solveVelocity = timer.GetMilliseconds(); // Integrate positions for (int i = 0; i < m_bodies.Count(); ++i) { Vec2 c = m_positions[i].c; float a = m_positions[i].a; Vec2 v = m_velocities[i].v; float w = m_velocities[i].w; // Check for large velocities Vec2 translation = h * v; if (Utilities.Dot(translation, translation) > Settings._maxTranslationSquared) { float ratio = Settings._maxTranslation / translation.Length(); v *= ratio; } float rotation = h * w; if (rotation * rotation > Settings._maxRotationSquared) { float ratio = Settings._maxRotation / Math.Abs(rotation); w *= ratio; } // Integrate c += h * v; a += h * w; m_positions[i].c = c; m_positions[i].a = a; m_velocities[i].v = v; m_velocities[i].w = w; } // Solve position constraints timer.Reset(); bool positionSolved = false; for (int i = 0; i < step.positionIterations; ++i) { bool contactsOkay = contactSolver.SolvePositionConstraints(); bool jointsOkay = true; for (int j = 0; j < m_joints.Count; ++j) { bool jointOkay = m_joints[j].SolvePositionConstraints(solverData); jointsOkay = jointsOkay && jointOkay; } if (contactsOkay && jointsOkay) { // Exit early if the position errors are small. positionSolved = true; break; } } // Copy state buffers back to the bodies for (int i = 0; i < m_bodies.Count(); ++i) { Body body = m_bodies[i]; body.m_sweep.c = m_positions[i].c; body.m_sweep.a = m_positions[i].a; body.m_linearVelocity = m_velocities[i].v; body.m_angularVelocity = m_velocities[i].w; body.SynchronizeTransform(); } profile.solvePosition = timer.GetMilliseconds(); Report(contactSolver.m_velocityConstraints); if (allowSleep) { float minSleepTime = Single.MaxValue; const float linTolSqr = Settings._linearSleepTolerance * Settings._linearSleepTolerance; const float angTolSqr = Settings._angularSleepTolerance * Settings._angularSleepTolerance; for (int i = 0; i < m_bodies.Count(); ++i) { Body b = m_bodies[i]; if (b.GetBodyType() == BodyType._staticBody) { continue; } if ((b.m_flags & Body.BodyFlags.e_autoSleepFlag) == 0 || b.m_angularVelocity * b.m_angularVelocity > angTolSqr || Utilities.Dot(b.m_linearVelocity, b.m_linearVelocity) > linTolSqr) { b.m_sleepTime = 0.0f; minSleepTime = 0.0f; } else { b.m_sleepTime += h; minSleepTime = Math.Min(minSleepTime, b.m_sleepTime); } } if (minSleepTime >= Settings._timeToSleep && positionSolved) { for (int i = 0; i < m_bodies.Count(); ++i) { Body b = m_bodies[i]; b.SetAwake(false); } } } }
// Broad-phase callback. public void AddPair(object proxyUserDataA, object proxyUserDataB) { FixtureProxy proxyA = (FixtureProxy)proxyUserDataA; FixtureProxy proxyB = (FixtureProxy)proxyUserDataB; Fixture fixtureA = proxyA.fixture; Fixture fixtureB = proxyB.fixture; int indexA = proxyA.childIndex; int indexB = proxyB.childIndex; Body bodyA = fixtureA.GetBody(); Body bodyB = fixtureB.GetBody(); // Are the fixtures on the same body? if (bodyA == bodyB) { return; } // TODO_ERIN use a hash table to remove a potential bottleneck when both // bodies have a lot of contacts. // Does a contact already exist? List <ContactEdge> edges = bodyB.GetContactList(); foreach (ContactEdge edge in edges) { if (edge.other == bodyA) { Fixture fA = edge.contact.FixtureA; Fixture fB = edge.contact.FixtureB; int iA = edge.contact.GetChildIndexA(); int iB = edge.contact.GetChildIndexB(); if (fA == fixtureA && fB == fixtureB && iA == indexA && iB == indexB) { // A contact already exists. return; } if (fA == fixtureB && fB == fixtureA && iA == indexB && iB == indexA) { // A contact already exists. return; } } } // Does a joint override collision? Is at least one body dynamic? if (bodyB.ShouldCollide(bodyA) == false) { return; } // Check user filtering. if ((m_contactFilter != null) && m_contactFilter.ShouldCollide(fixtureA, fixtureB) == false) { return; } // Call the factory. Contact c = Contact.Create(fixtureA, indexA, fixtureB, indexB); if (c == null) { return; } // Contact creation may swap fixtures. fixtureA = c.FixtureA; fixtureB = c.FixtureB; indexA = c.GetChildIndexA(); indexB = c.GetChildIndexB(); bodyA = fixtureA.GetBody(); bodyB = fixtureB.GetBody(); // Insert into the world. m_contactList.Add(c); // Connect to island graph. // Connect to body A c.m_nodeA.contact = c; c.m_nodeA.other = bodyB; bodyA.m_contactList.Add(c.m_nodeA); // Connect to body B c.m_nodeB.contact = c; c.m_nodeB.other = bodyA; bodyB.m_contactList.Add(c.m_nodeB); // Wake up the bodies if (fixtureA.IsSensor == false && fixtureB.IsSensor == false) { bodyA.SetAwake(true); bodyB.SetAwake(true); } }
// Update the contact manifold and touching status. // Note: do not assume the fixture AABBs are overlapping or are valid. internal void Update(IContactListener listener) { Manifold oldManifold = _manifold; // Re-enable this contact. _flags |= ContactFlags.Enabled; bool touching = false; bool wasTouching = (_flags & ContactFlags.Touching) == ContactFlags.Touching; bool sensorA = _fixtureA.IsSensor(); bool sensorB = _fixtureB.IsSensor(); bool sensor = sensorA || sensorB; Body bodyA = _fixtureA.GetBody(); Body bodyB = _fixtureB.GetBody(); Transform xfA; bodyA.GetTransform(out xfA); Transform xfB; bodyB.GetTransform(out xfB); // Is this contact a sensor? if (sensor) { Shape shapeA = _fixtureA.GetShape(); Shape shapeB = _fixtureB.GetShape(); touching = AABB.TestOverlap(shapeA, _indexA, shapeB, _indexB, ref xfA, ref xfB); // Sensors don't generate manifolds. _manifold._pointCount = 0; } else { Evaluate(ref _manifold, ref xfA, ref xfB); touching = _manifold._pointCount > 0; // Match old contact ids to new contact ids and copy the // stored impulses to warm start the solver. for (int i = 0; i < _manifold._pointCount; ++i) { ManifoldPoint mp2 = _manifold._points[i]; mp2.NormalImpulse = 0.0f; mp2.TangentImpulse = 0.0f; ContactID id2 = mp2.Id; bool found = false; for (int j = 0; j < oldManifold._pointCount; ++j) { ManifoldPoint mp1 = oldManifold._points[j]; if (mp1.Id.Key == id2.Key) { mp2.NormalImpulse = mp1.NormalImpulse; mp2.TangentImpulse = mp1.TangentImpulse; found = true; break; } } if (found == false) { mp2.NormalImpulse = 0.0f; mp2.TangentImpulse = 0.0f; } _manifold._points[i] = mp2; } if (touching != wasTouching) { bodyA.SetAwake(true); bodyB.SetAwake(true); } } if (touching) { _flags |= ContactFlags.Touching; } else { _flags &= ~ContactFlags.Touching; } if (wasTouching == false && touching == true && null != listener) { listener.BeginContact(this); } if (wasTouching == true && touching == false && null != listener) { listener.EndContact(this); } if (sensor == false && null != listener) { listener.PreSolve(this, ref oldManifold); } }
public void Solve(ref TimeStep step, Vector2 gravity, bool allowSleep) { // Integrate velocities and apply damping. for (int i = 0; i < _bodyCount; ++i) { Body b = _bodies[i]; if (b.GetType() != BodyType.Dynamic) { continue; } // Integrate velocities. b._linearVelocity += step.dt * (gravity + b._invMass * b._force); b._angularVelocity += 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._linearVelocity *= MathUtils.Clamp(1.0f - step.dt * b._linearDamping, 0.0f, 1.0f); b._angularVelocity *= 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].GetFixtureA(); Fixture fixtureB = _contacts[i2].GetFixtureB(); Body bodyA = fixtureA.GetBody(); Body bodyB = fixtureB.GetBody(); bool nonStatic = bodyA.GetType() != BodyType.Static && bodyB.GetType() != BodyType.Static; if (nonStatic) { ++i1; //b2Swap(_contacts[i1], _contacts[i2]); Contact temp = _contacts[i1]; _contacts[i1] = _contacts[i2]; _contacts[i2] = temp; } } // Initialize velocity constraints. _contactSolver.Reset(_contacts, _contactCount, step.dtRatio); _contactSolver.WarmStart(); for (int i = 0; i < _jointCount; ++i) { _joints[i].InitVelocityConstraints(ref step); } // Solve velocity constraints. for (int i = 0; i < step.velocityIterations; ++i) { for (int j = 0; j < _jointCount; ++j) { _joints[j].SolveVelocityConstraints(ref step); } _contactSolver.SolveVelocityConstraints(); } // Post-solve (store impulses for warm starting). _contactSolver.StoreImpulses(); // Integrate positions. for (int i = 0; i < _bodyCount; ++i) { Body b = _bodies[i]; if (b.GetType() == BodyType.Static) { continue; } // Check for large velocities. Vector2 translation = step.dt * b._linearVelocity; if (Vector2.Dot(translation, translation) > Settings.b2_maxTranslationSquared) { float ratio = Settings.b2_maxTranslation / translation.magnitude; b._linearVelocity *= ratio; } float rotation = step.dt * b._angularVelocity; if (rotation * rotation > Settings.b2_maxRotationSquared) { float ratio = Settings.b2_maxRotation / Math.Abs(rotation); b._angularVelocity *= ratio; } // Store positions for continuous collision. b._sweep.c0 = b._sweep.c; b._sweep.a0 = b._sweep.a; // Integrate b._sweep.c += step.dt * b._linearVelocity; b._sweep.a += step.dt * b._angularVelocity; // Compute new transform b.SynchronizeTransform(); // Note: shapes are synchronized later. } // Iterate over constraints. for (int i = 0; i < step.positionIterations; ++i) { bool contactsOkay = _contactSolver.SolvePositionConstraints(Settings.b2_contactBaumgarte); bool jointsOkay = true; for (int j = 0; j < _jointCount; ++j) { bool jointOkay = _joints[j].SolvePositionConstraints(Settings.b2_contactBaumgarte); jointsOkay = jointsOkay && jointOkay; } if (contactsOkay && jointsOkay) { // Exit early if the position errors are small. break; } } Report(_contactSolver._constraints); if (allowSleep) { float minSleepTime = Settings.b2_maxFloat; const float linTolSqr = Settings.b2_linearSleepTolerance * Settings.b2_linearSleepTolerance; const float angTolSqr = Settings.b2_angularSleepTolerance * Settings.b2_angularSleepTolerance; for (int i = 0; i < _bodyCount; ++i) { Body b = _bodies[i]; if (b.GetType() == BodyType.Static) { continue; } if ((b._flags & BodyFlags.AutoSleep) == 0) { b._sleepTime = 0.0f; minSleepTime = 0.0f; } if ((b._flags & BodyFlags.AutoSleep) == 0 || b._angularVelocity * b._angularVelocity > angTolSqr || Vector2.Dot(b._linearVelocity, b._linearVelocity) > linTolSqr) { b._sleepTime = 0.0f; minSleepTime = 0.0f; } else { b._sleepTime += step.dt; minSleepTime = Math.Min(minSleepTime, b._sleepTime); } } if (minSleepTime >= Settings.b2_timeToSleep) { for (int i = 0; i < _bodyCount; ++i) { Body b = _bodies[i]; b.SetAwake(false); } } } }
void Solve(ref TimeStep step) { // Size the island for the worst case. _island.Reset(_bodyCount, _contactManager._contactCount, _jointCount, _contactManager.ContactListener); // Clear all the island flags. for (Body b = _bodyList; b != null; b = b._next) { b._flags &= ~BodyFlags.Island; } for (Contact c = _contactManager._contactList; c != null; c = c._next) { c._flags &= ~ContactFlags.Island; } for (Joint j = _jointList; j != null; j = j._next) { j._islandFlag = false; } // Build and simulate all awake islands. int stackSize = _bodyCount; if (stackSize > stack.Length) { stack = new Body[Math.Max(stack.Length * 2, stackSize)]; } for (Body seed = _bodyList; seed != null; seed = seed._next) { if ((seed._flags & (BodyFlags.Island)) != BodyFlags.None) { continue; } if (seed.IsAwake() == false || seed.IsActive() == false) { continue; } // The seed can be dynamic or kinematic. if (seed.GetType() == 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 raint graph. while (stackCount > 0) { // Grab the next body off the stack and add it to the island. Body b = stack[--stackCount]; //Debug.Assert(b.IsActive() == true); _island.Add(b); // Make sure the body is awake. b.SetAwake(true); // To keep islands as small as possible, we don't // propagate islands across static bodies. if (b.GetType() == 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.IsEnabled() || !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; Body 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 == true) { continue; } Body other = je.Other; // Don't simulate joints connected to inactive bodies. if (other.IsActive() == 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; } } _island.Solve(ref step, Gravity, _allowSleep); // Post solve cleanup. for (int i = 0; i < _island._bodyCount; ++i) { // Allow static bodies to participate in other islands. Body b = _island._bodies[i]; if (b.GetType() == BodyType.Static) { b._flags &= ~BodyFlags.Island; } } } // Synchronize fixtures, check for out of range bodies. for (Body b = _bodyList; b != null; b = b.GetNext()) { // If a body was not in an island then it did not move. if ((b._flags & BodyFlags.Island) != BodyFlags.Island) { continue; } if (b.GetType() == BodyType.Static) { continue; } // Update fixtures (for broad-phase). b.SynchronizeFixtures(); } // Look for new contacts. _contactManager.FindNewContacts(); }
/// Destroy a joint. This may cause the connected bodies to begin colliding. /// @warning This function is locked during callbacks. public void DestroyJoint(Joint j) { //Debug.Assert(!IsLocked); if (IsLocked) { return; } bool collideConnected = j._collideConnected; // Remove from the doubly linked list. if (j._prev != null) { j._prev._next = j._next; } if (j._next != null) { j._next._prev = j._prev; } if (j == _jointList) { _jointList = j._next; } // Disconnect from island graph. Body bodyA = j._bodyA; Body bodyB = j._bodyB; // Wake up connected bodies. bodyA.SetAwake(true); bodyB.SetAwake(true); // Remove from body 1. if (j._edgeA.Prev != null) { j._edgeA.Prev.Next = j._edgeA.Next; } if (j._edgeA.Next != null) { j._edgeA.Next.Prev = j._edgeA.Prev; } if (j._edgeA == bodyA._jointList) { bodyA._jointList = j._edgeA.Next; } j._edgeA.Prev = null; j._edgeA.Next = null; // Remove from body 2 if (j._edgeB.Prev != null) { j._edgeB.Prev.Next = j._edgeB.Next; } if (j._edgeB.Next != null) { j._edgeB.Next.Prev = j._edgeB.Prev; } if (j._edgeB == bodyB._jointList) { bodyB._jointList = j._edgeB.Next; } j._edgeB.Prev = null; j._edgeB.Next = null; //Debug.Assert(_jointCount > 0); --_jointCount; // If the joint prevents collisions, then flag any contacts for filtering. if (collideConnected == false) { ContactEdge edge = bodyB.GetContactList(); while (edge != null) { if (edge.Other == bodyA) { // Flag the contact for filtering at the next time step (where either // body is awake). edge.Contact.FlagForFiltering(); } edge = edge.Next; } } }
private void Solve(TimeStep step) { m_profile.solveInit = 0.0f; m_profile.solveVelocity = 0.0f; m_profile.solvePosition = 0.0f; // Size the island for the worst case. Island island = new Island(m_contactManager.m_contactListener); // Clear all the island flags. foreach (Body b in m_bodyList) { b.m_flags &= ~Body.BodyFlags.e_islandFlag; } foreach (Contact c in m_contactManager.m_contactList) { c.m_flags &= ~ContactFlags.e_islandFlag; } foreach (Joint j in m_jointList) { j.m_islandFlag = false; } // Build and simulate all awake islands. List <Body> stack = new List <Body>(m_bodyList.Count()); foreach (Body seed in m_bodyList) { if (seed.m_flags.HasFlag(Body.BodyFlags.e_islandFlag)) { continue; } if (seed.IsAwake() == false || seed.IsActive() == false) { continue; } // The seed can be dynamic or kinematic. if (seed.GetBodyType() == BodyType._staticBody) { continue; } // Reset island and stack. island.Clear(); int stackCount = 0; stack.Add(seed); stackCount++; seed.m_flags |= Body.BodyFlags.e_islandFlag; // 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. Body b = stack[--stackCount]; Utilities.Assert(b.IsActive() == true); island.Add(b); // Make sure the body is awake. b.SetAwake(true); // To keep islands as small as possible, we don't // propagate islands across static bodies. if (b.GetBodyType() == BodyType._staticBody) { continue; } // Search all contacts connected to this body. foreach (ContactEdge ce in b.m_contactList) { Contact contact = ce.contact; // Has this contact already been added to an island? if (contact.m_flags.HasFlag(ContactFlags.e_islandFlag)) { continue; } // Is this contact solid and touching? if (contact.IsEnabled() == false || contact.IsTouching() == false) { continue; } // Skip sensors. bool sensorA = contact.m_fixtureA.m_isSensor; bool sensorB = contact.m_fixtureB.m_isSensor; if (sensorA || sensorB) { continue; } island.Add(contact); contact.m_flags |= ContactFlags.e_islandFlag; Body other = ce.other; // Was the other body already added to this island? if (other.m_flags.HasFlag(Body.BodyFlags.e_islandFlag)) { continue; } Utilities.Assert(stackCount < m_bodyList.Count()); stack.Add(other); stackCount++; other.m_flags |= Body.BodyFlags.e_islandFlag; } // Search all joints connect to this body. foreach (JointEdge je in b.m_jointList) { if (je.joint.m_islandFlag == true) { continue; } Body other = je.other; // Don't simulate joints connected to inactive bodies. if (other.IsActive() == false) { continue; } island.Add(je.joint); je.joint.m_islandFlag = true; if (other.m_flags.HasFlag(Body.BodyFlags.e_islandFlag)) { continue; } stack.Add(other); stackCount++; other.m_flags |= Body.BodyFlags.e_islandFlag; } } Profile profile = new Profile(); island.Solve(profile, step, m_gravity, m_allowSleep); m_profile.solveInit += profile.solveInit; m_profile.solveVelocity += profile.solveVelocity; m_profile.solvePosition += profile.solvePosition; // Post solve cleanup. for (int i = 0; i < island.m_bodies.Count(); ++i) { // Allow static bodies to participate in other islands. Body b = island.m_bodies[i]; if (b.GetBodyType() == BodyType._staticBody) { b.m_flags &= ~Body.BodyFlags.e_islandFlag; } } } { Timer timer = new Timer(); // Synchronize fixtures, check for out of range bodies. foreach (Body b in m_bodyList) { // If a body was not in an island then it did not move. if ((b.m_flags & Body.BodyFlags.e_islandFlag) == 0) { continue; } if (b.GetBodyType() == BodyType._staticBody) { continue; } // Update fixtures (for broad-phase). b.SynchronizeFixtures(); } // Look for new contacts. m_contactManager.FindNewContacts(); m_profile.broadphase = timer.GetMilliseconds(); } }
private void SolveTOI(TimeStep step) { Island island = new Island(m_contactManager.m_contactListener); if (m_stepComplete) { foreach (Body b in m_bodyList) { b.m_flags &= ~Body.BodyFlags.e_islandFlag; b.m_sweep.alpha0 = 0.0f; } foreach (Contact c in m_contactManager.m_contactList) { // Invalidate TOI c.m_flags &= ~(ContactFlags.e_toiFlag | ContactFlags.e_islandFlag); c.m_toiCount = 0; c.m_toi = 1.0f; } } Fixture fA = null; Fixture fB = null; Body bA = null; Body bB = null; // Find TOI events and solve them. for (;;) { // Find the first TOI. Contact minContact = null; float minAlpha = 1.0f; foreach (Contact c in m_contactManager.m_contactList) { // Is this contact disabled? if (c.IsEnabled() == false) { continue; } // Prevent excessive sub-stepping. if (c.m_toiCount > Settings._maxSubSteps) { continue; } float alpha = 1.0f; if (c.m_flags.HasFlag(ContactFlags.e_toiFlag)) { // This contact has a valid cached TOI. alpha = c.m_toi; } else { fA = c.FixtureA; fB = c.FixtureB; // Is there a sensor? if (fA.IsSensor || fB.IsSensor) { continue; } bA = fA.GetBody(); bB = fB.GetBody(); BodyType typeA = bA.m_type; BodyType typeB = bB.m_type; Utilities.Assert(typeA == BodyType._dynamicBody || typeB == BodyType._dynamicBody); bool activeA = bA.IsAwake() && typeA != BodyType._staticBody; bool activeB = bB.IsAwake() && typeB != BodyType._staticBody; // Is at least one body active (awake and dynamic or kinematic)? if (activeA == false && activeB == false) { continue; } bool collideA = bA.IsBullet() || typeA != BodyType._dynamicBody; bool collideB = bB.IsBullet() || typeB != BodyType._dynamicBody; // 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.m_sweep.alpha0; if (bA.m_sweep.alpha0 < bB.m_sweep.alpha0) { alpha0 = bB.m_sweep.alpha0; bA.m_sweep.Advance(alpha0); } else if (bB.m_sweep.alpha0 < bA.m_sweep.alpha0) { alpha0 = bA.m_sweep.alpha0; bB.m_sweep.Advance(alpha0); } Utilities.Assert(alpha0 < 1.0f); int indexA = c.GetChildIndexA(); int indexB = c.GetChildIndexB(); // Compute the time of impact in interval [0, minTOI] TOIInput input = new TOIInput(); input.proxyA.Set(fA.GetShape(), indexA); input.proxyB.Set(fB.GetShape(), indexB); input.sweepA = bA.m_sweep; input.sweepB = bB.m_sweep; input.tMax = 1.0f; TOIOutput output; Utilities.TimeOfImpact(out output, input); // Beta is the fraction of the remaining portion of the . float beta = output.t; if (output.state == TOIOutput.State.e_touching) { alpha = Math.Min(alpha0 + (1.0f - alpha0) * beta, 1.0f); } else { alpha = 1.0f; } c.m_toi = alpha; c.m_flags |= ContactFlags.e_toiFlag; } if (alpha < minAlpha) { // This is the minimum TOI found so far. minContact = c; minAlpha = alpha; } } if (minContact == null || 1.0f - 10.0f * Single.Epsilon < minAlpha) { // No more TOI events. Done! m_stepComplete = true; break; } // Advance the bodies to the TOI. fA = minContact.FixtureA; fB = minContact.FixtureB; bA = fA.GetBody(); bB = fB.GetBody(); Sweep backup1 = bA.m_sweep; Sweep backup2 = bB.m_sweep; bA.Advance(minAlpha); bB.Advance(minAlpha); // The TOI contact likely has some new contact points. minContact.Update(m_contactManager.m_contactListener); minContact.m_flags &= ~ContactFlags.e_toiFlag; ++minContact.m_toiCount; // Is the contact solid? if (minContact.IsEnabled() == false || minContact.IsTouching() == false) { // Restore the sweeps. minContact.SetEnabled(false); bA.m_sweep = backup1; bB.m_sweep = backup2; bA.SynchronizeTransform(); bB.SynchronizeTransform(); continue; } bA.SetAwake(true); bB.SetAwake(true); // Build the island island.Clear(); island.Add(bA); island.Add(bB); island.Add(minContact); bA.m_flags |= Body.BodyFlags.e_islandFlag; bB.m_flags |= Body.BodyFlags.e_islandFlag; minContact.m_flags |= ContactFlags.e_islandFlag; // Get contacts on bodyA and bodyB. Body[] bodies = { bA, bB }; for (int i = 0; i < 2; ++i) { Body body = bodies[i]; if (body.m_type == BodyType._dynamicBody) { foreach (ContactEdge ce in body.m_contactList) { throw new NotImplementedException(); //if (island.m_bodies.Count() == island.m_bodyCapacity) //{ // break; //} //if (island.m_bodies.Count() == island.m_contactCapacity) //{ // break; //} //Contact* contact = ce.contact; //// Has this contact already been added to the island? //if (contact.m_flags & ContactFlags.e_islandFlag) //{ // continue; //} //// Only add static, kinematic, or bullet bodies. //Body* other = ce.other; //if (other.m_type == _dynamicBody && // body.IsBullet() == false && other.IsBullet() == false) //{ // continue; //} //// Skip sensors. //bool sensorA = contact.m_fixtureA.m_isSensor; //bool sensorB = contact.m_fixtureB.m_isSensor; //if (sensorA || sensorB) //{ // continue; //} //// Tentatively advance the body to the TOI. //Sweep backup = other.m_sweep; //if ((other.m_flags & Body.BodyFlags.e_islandFlag) == 0) //{ // other.Advance(minAlpha); //} //// Update the contact points //contact.Update(m_contactManager.m_contactListener); //// Was the contact disabled by the user? //if (contact.IsEnabled() == false) //{ // other.m_sweep = backup; // other.SynchronizeTransform(); // continue; //} //// Are there contact points? //if (contact.IsTouching() == false) //{ // other.m_sweep = backup; // other.SynchronizeTransform(); // continue; //} //// Add the contact to the island //contact.m_flags |= ContactFlags.e_islandFlag; //island.Add(contact); //// Has the other body already been added to the island? //if (other.m_flags & Body.BodyFlags.e_islandFlag) //{ // continue; //} //// Add the other body to the island. //other.m_flags |= Body.BodyFlags.e_islandFlag; //if (other.m_type != _staticBody) //{ // other.SetAwake(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(subStep, bA.m_islandIndex, bB.m_islandIndex); // Reset island flags and synchronize broad-phase proxies. for (int i = 0; i < island.m_bodies.Count(); ++i) { throw new NotImplementedException(); //Body* body = island.m_bodies[i]; //body.m_flags &= ~Body.BodyFlags.e_islandFlag; //if (body.m_type != _dynamicBody) //{ // continue; //} //body.SynchronizeFixtures(); //// Invalidate all contact TOIs on this displaced body. //for (ContactEdge* ce = body.m_contactList; ce; ce = ce.next) //{ // ce.contact.m_flags &= ~(ContactFlags.e_toiFlag | ContactFlags.e_islandFlag); //} } // Commit fixture proxy movements to the broad-phase so that new contacts are created. // Also, some contacts can be destroyed. m_contactManager.FindNewContacts(); if (m_subStepping) { m_stepComplete = false; break; } } }
// Update the contact manifold and touching status. // Note: do not assume the fixture AABBs are overlapping or are valid. internal void Update(ContactListener listener) { Manifold oldManifold = m_manifold; // Re-enable this contact. m_flags |= ContactFlags.e_enabledFlag; bool touching = false; bool wasTouching = (m_flags & ContactFlags.e_touchingFlag) == ContactFlags.e_touchingFlag; bool sensorA = m_fixtureA.IsSensor; bool sensorB = m_fixtureB.IsSensor; bool sensor = sensorA || sensorB; Body bodyA = m_fixtureA.GetBody(); Body bodyB = m_fixtureB.GetBody(); Transform xfA = bodyA.GetTransform(); Transform xfB = bodyB.GetTransform(); // Is this contact a sensor? if (sensor) { Shape shapeA = m_fixtureA.GetShape(); Shape shapeB = m_fixtureB.GetShape(); touching = Collision.TestOverlap(shapeA, m_indexA, shapeB, m_indexB, xfA, xfB); // Sensors don't generate manifolds. m_manifold.points.Clear(); } else { Evaluate(out m_manifold, xfA, xfB); touching = m_manifold.points.Count() > 0; // Match old contact ids to new contact ids and copy the // stored impulses to warm start the solver. for (int i = 0; i < m_manifold.points.Count(); ++i) { ManifoldPoint mp2 = m_manifold.points[i]; mp2.normalImpulse = 0.0f; mp2.tangentImpulse = 0.0f; ContactID id2 = mp2.id; for (int j = 0; j < oldManifold.points.Count(); ++j) { ManifoldPoint mp1 = oldManifold.points[j]; if (mp1.id.key == id2.key) { mp2.normalImpulse = mp1.normalImpulse; mp2.tangentImpulse = mp1.tangentImpulse; break; } } } if (touching != wasTouching) { bodyA.SetAwake(true); bodyB.SetAwake(true); } } if (touching) { m_flags |= ContactFlags.e_touchingFlag; } else { m_flags &= ~ContactFlags.e_touchingFlag; } if (wasTouching == false && touching == true && listener != null) { listener.BeginContact(this); } if (wasTouching == true && touching == false && listener != null) { listener.EndContact(this); } if (sensor == false && touching && listener != null) { listener.PreSolve(this, oldManifold); } }