/// Set the contact filtering data. This is an expensive operation and should /// not be called frequently. This will not update contacts until the next time /// step when either parent body is awake. public void SetFilterData(ref Filter filter) { _filter = filter; if (_body == null) { return; } // Flag associated contacts for filtering. ContactEdge edge = _body.GetConactList(); while (edge != null) { Contact contact = edge.Contact; Fixture fixtureA = contact.GetFixtureA(); Fixture fixtureB = contact.GetFixtureB(); if (fixtureA == this || fixtureB == this) { contact.FlagForFiltering(); } } }
/// Compute the mass properties from the attached fixture. You typically call this /// after adding all the fixtures. If you add or remove fixtures later, you may want /// to call this again. Note that this changes the center of mass position. public void SetMassFromShapes() { Debug.Assert(_world.IsLocked == false); if (_world.IsLocked == true) { return; } // Compute mass data from shapes. Each shape has its own density. _mass = 0.0f; _invMass = 0.0f; _I = 0.0f; _invI = 0.0f; Vector2 center = Vector2.Zero; for (Fixture f = _fixtureList; f != null; f = f._next) { MassData massData; f.ComputeMass(out massData); _mass += massData.mass; center += massData.mass * massData.center; _I += massData.i; } // Compute center of mass, and shift the origin to the COM. if (_mass > 0.0f) { _invMass = 1.0f / _mass; center *= _invMass; } if (_I > 0.0f && (_flags & BodyFlags.FixedRotation) == 0) { // Center the inertia about the center of mass. _I -= _mass * Vector2.Dot(center, center); Debug.Assert(_I > 0.0f); _invI = 1.0f / _I; } else { _I = 0.0f; _invI = 0.0f; } // Move center of mass. _sweep.localCenter = center; _sweep.c0 = _sweep.c = MathUtils.Multiply(ref _xf, _sweep.localCenter); BodyType oldType = _type; if (_invMass == 0.0f && _invI == 0.0f) { _type = BodyType.Static; } else { _type = BodyType.Dynamic; } // If the body type changed, we need to flag contacts for filtering. if (oldType != _type) { for (ContactEdge ce = _contactList; ce != null; ce = ce.Next) { ce.Contact.FlagForFiltering(); } } }
void SolveTOI(ref TimeStep step) { // Reserve an island and a queue for TOI island solution. _island.Reset(_bodyCount, Settings.b2_maxTOIContactsPerIsland, Settings.b2_maxTOIJointsPerIsland, _contactManager.ContactListener); //Simple one pass queue //Relies on the fact that we're only making one pass //through and each body can only be pushed/popped once. //To push: // queue[queueStart+queueSize++] = newElement; //To pop: // poppedElement = queue[queueStart++]; // --queueSize; //#warning More Body array Allocs int queueCapacity = _bodyCount; Body[] queue = new Body[_bodyCount]; for (Body b = _bodyList; b != null; b = b._next) { b._flags &= ~BodyFlags.Island; b._sweep.t0 = 0.0f; } for (Contact c = _contactManager._contactList; c != null; c = c._next) { // Invalidate TOI c._flags &= ~(ContactFlags.Toi | ContactFlags.Island); } for (Joint j = _jointList; j != null; j = j._next) { j._islandFlag = false; } // Find TOI events and solve them. for (;;) { // Find the first TOI. Contact minContact = null; float minTOI = 1.0f; for (Contact c = _contactManager._contactList; c != null; c = c._next) { if ((c._flags & (ContactFlags.Slow | ContactFlags.NonSolid)) != ContactFlags.None) { continue; } // TODO_ERIN keep a counter on the contact, only respond to M TOIs per contact. float toi = 1.0f; if ((c._flags & ContactFlags.Toi) != ContactFlags.None) { // This contact has a valid cached TOI. toi = c._toi; } else { // Compute the TOI for this contact. Fixture s1 = c.GetFixtureA(); Fixture s2 = c.GetFixtureB(); Body b1 = s1.GetBody(); Body b2 = s2.GetBody(); if ((b1.IsStatic || b1.IsSleeping) && (b2.IsStatic || b2.IsSleeping)) { continue; } // Put the sweeps onto the same time interval. float t0 = b1._sweep.t0; if (b1._sweep.t0 < b2._sweep.t0) { t0 = b2._sweep.t0; b1._sweep.Advance(t0); } else if (b2._sweep.t0 < b1._sweep.t0) { t0 = b1._sweep.t0; b2._sweep.Advance(t0); } Debug.Assert(t0 < 1.0f); // Compute the time of impact. toi = c.ComputeTOI(ref b1._sweep, ref b2._sweep); //CalculateTimeOfImpact(c._fixtureA.GetShape(), b1._sweep, c._fixtureB.GetShape(), b2._sweep); Debug.Assert(0.0f <= toi && toi <= 1.0f); // If the TOI is in range ... if (0.0f < toi && toi < 1.0f) { // Interpolate on the actual range. toi = Math.Min((1.0f - toi) * t0 + toi, 1.0f); } c._toi = toi; c._flags |= ContactFlags.Toi; } if (Settings.b2_FLT_EPSILON < toi && toi < minTOI) { // This is the minimum TOI found so far. minContact = c; minTOI = toi; } } if (minContact == null || 1.0f - 100.0f * Settings.b2_FLT_EPSILON < minTOI) { // No more TOI events. Done! break; } // Advance the bodies to the TOI. Fixture s1_2 = minContact.GetFixtureA(); Fixture s2_2 = minContact.GetFixtureB(); Body b1_2 = s1_2.GetBody(); Body b2_2 = s2_2.GetBody(); b1_2.Advance(minTOI); b2_2.Advance(minTOI); // The TOI contact likely has some new contact points. minContact.Update(_contactManager.ContactListener); minContact._flags &= ~ContactFlags.Toi; if ((minContact._flags & ContactFlags.Touch) == 0) { // This shouldn't happen. Numerical error? //Debug.Assert(false); continue; } // Build the TOI island. We need a dynamic seed. Body seed = b1_2; if (seed.IsStatic) { seed = b2_2; } // Reset island and queue. _island.Clear(); int queueStart = 0; // starting index for queue int queueSize = 0; // elements in queue queue[queueStart + queueSize++] = seed; seed._flags |= BodyFlags.Island; // Perform a breadth first search (BFS) on the contact/joint graph. while (queueSize > 0) { // Grab the next body off the stack and add it to the island. Body b = queue[queueStart++]; --queueSize; _island.Add(b); // Make sure the body is awake. b._flags &= ~BodyFlags.Sleep; // To keep islands as small as possible, we don't // propagate islands across static bodies. if (b.IsStatic) { continue; } // Search all contacts connected to this body. for (ContactEdge cEdge = b._contactList; cEdge != null; cEdge = cEdge.Next) { // Does the TOI island still have space for contacts? if (_island._contacts.Count == _island._contactCapacity) { continue; } // Has this contact already been added to an island? Skip slow or non-solid contacts. if ((cEdge.Contact._flags & (ContactFlags.Island | ContactFlags.Slow | ContactFlags.NonSolid)) != ContactFlags.None) { continue; } // Is this contact touching? For performance we are not updating this contact. if ((cEdge.Contact._flags & ContactFlags.Touch) == 0) { continue; } _island.Add(cEdge.Contact); cEdge.Contact._flags |= ContactFlags.Island; // Update other body. Body other = cEdge.Other; // Was the other body already added to this island? if ((other._flags & BodyFlags.Island) != BodyFlags.None) { continue; } // March forward, this can do no harm since this is the min TOI. if (other.IsStatic == false) { other.Advance(minTOI); other.WakeUp(); } Debug.Assert(queueStart + queueSize < queueCapacity); queue[queueStart + queueSize] = other; ++queueSize; other._flags |= BodyFlags.Island; } for (JointEdge jEdge = b._jointList; jEdge != null; jEdge = jEdge.Next) { if (_island._jointCount == _island._jointCapacity) { continue; } if (jEdge.Joint._islandFlag == true) { continue; } _island.Add(jEdge.Joint); jEdge.Joint._islandFlag = true; Body other = jEdge.Other; if ((other._flags & BodyFlags.Island) != BodyFlags.None) { continue; } if (!other.IsStatic) { other.Advance(minTOI); other.WakeUp(); } Debug.Assert(queueStart + queueSize < queueCapacity); queue[queueStart + queueSize] = other; ++queueSize; other._flags |= BodyFlags.Island; } } TimeStep subStep; subStep.warmStarting = false; subStep.dt = (1.0f - minTOI) * step.dt; subStep.inv_dt = 1.0f / subStep.dt; subStep.dtRatio = 0.0f; subStep.velocityIterations = step.velocityIterations; subStep.positionIterations = step.positionIterations; _island.SolveTOI(ref subStep); // Post solve cleanup. for (int i = 0; i < _island._bodyCount; ++i) { // Allow bodies to participate in future TOI islands. Body b = _island._bodies[i]; b._flags &= ~BodyFlags.Island; if ((b._flags & (BodyFlags.Sleep | BodyFlags.Frozen)) != BodyFlags.None) { continue; } if (b.IsStatic) { continue; } // Update fixtures (for broad-phase). b.SynchronizeFixtures(); // Invalidate all contact TOIs associated with this body. Some of these // may not be in the island because they were not touching. for (ContactEdge ce = b._contactList; ce != null; ce = ce.Next) { ce.Contact._flags &= ~ContactFlags.Toi; } } int contactCount = _island._contacts.Count; for (int i = 0; i < contactCount; ++i) { // Allow contacts to participate in future TOI islands. Contact c = _island._contacts[i]; c._flags &= ~(ContactFlags.Toi | ContactFlags.Island); } for (int i = 0; i < _island._jointCount; ++i) { // Allow joints to participate in future TOI islands. Joint j = _island._joints[i]; j._islandFlag = false; } // Commit fixture proxy movements to the broad-phase so that new contacts are created. // Also, some contacts can be destroyed. _contactManager.FindNewContacts(); } }
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. //#warning Remove extra allocs int stackSize = _bodyCount; Body[] stack = new Body[_bodyCount]; for (Body seed = _bodyList; seed != null; seed = seed._next) { if ((seed._flags & (BodyFlags.Island | BodyFlags.Sleep | BodyFlags.Frozen)) != BodyFlags.None) { continue; } if (seed.IsStatic) { 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]; _island.Add(b); // Make sure the body is awake. b._flags &= ~BodyFlags.Sleep; // To keep islands as small as possible, we don't // propagate islands across static bodies. if (b.IsStatic) { continue; } // Search all contacts connected to this body. for (ContactEdge ce = b._contactList; ce != null; ce = ce.Next) { // Has this contact already been added to an island? // Is this contact non-solid (involves a sensor). if ((ce.Contact._flags & (ContactFlags.Island | ContactFlags.NonSolid)) != ContactFlags.None) { continue; } // Is this contact touching? if ((ce.Contact._flags & ContactFlags.Touch) == ContactFlags.None) { continue; } _island.Add(ce.Contact); ce.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; } _island.Add(je.Joint); je.Joint._islandFlag = true; Body other = je.Other; 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.IsStatic) { b._flags &= ~BodyFlags.Island; } } } // Synchronize fixtures, check for out of range bodies. for (Body b = _bodyList; b != null; b = b.GetNext()) { if ((b._flags & (BodyFlags.Sleep | BodyFlags.Frozen)) != BodyFlags.None) { continue; } if (b.IsStatic) { 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.WakeUp(); bodyB.WakeUp(); // 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.GetConactList(); 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; } } }
/// Create a joint to rain bodies together. No reference to the definition /// is retained. This may cause the connected bodies to cease colliding. /// @warning This function is locked during callbacks. public Joint CreateJoint(JointDef def) { Debug.Assert(!IsLocked); if (IsLocked) { return(null); } Joint j = Joint.Create(def); // Connect to the world list. j._prev = null; j._next = _jointList; if (_jointList != null) { _jointList._prev = j; } _jointList = j; ++_jointCount; // Connect to the bodies' doubly linked lists. j._edgeA.Joint = j; j._edgeA.Other = j._bodyB; j._edgeA.Prev = null; j._edgeA.Next = j._bodyA._jointList; if (j._bodyA._jointList != null) { j._bodyA._jointList.Prev = j._edgeA; } j._bodyA._jointList = j._edgeA; j._edgeB.Joint = j; j._edgeB.Other = j._bodyA; j._edgeB.Prev = null; j._edgeB.Next = j._bodyB._jointList; if (j._bodyB._jointList != null) { j._bodyB._jointList.Prev = j._edgeB; } j._bodyB._jointList = j._edgeB; Body bodyA = def.body1; Body bodyB = def.body2; bool staticA = bodyA.IsStatic; bool staticB = bodyB.IsStatic; // If the joint prevents collisions, then flag any contacts for filtering. if (def.collideConnected == false && (staticA == false || staticB == false)) { // Ensure we iterate over contacts on a dynamic body (usually have less contacts // than a static body). Ideally we will have a contact count on both bodies. if (staticB) { MathUtils.Swap(ref bodyA, ref bodyB); } ContactEdge edge = bodyB.GetConactList(); 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; } } // Note: creating a joint doesn't wake the bodies. return(j); }
/// Destroy a rigid body given a definition. No reference to the definition /// is retained. This function is locked during callbacks. /// @warning This automatically deletes all associated shapes and joints. /// @warning This function is locked during callbacks. public void DestroyBody(Body b) { Debug.Assert(_bodyCount > 0); Debug.Assert(!IsLocked); if (IsLocked) { return; } // Delete the attached joints. JointEdge je = b._jointList; while (je != null) { JointEdge je0 = je; je = je.Next; if (DestructionListener != null) { DestructionListener.SayGoodbye(je0.Joint); } DestroyJoint(je0.Joint); } b._jointList = null; // Delete the attached contacts. ContactEdge ce = b._contactList; while (ce != null) { ContactEdge ce0 = ce; ce = ce.Next; _contactManager.Destroy(ce0.Contact); } b._contactList = null; // Delete the attached fixtures. This destroys broad-phase proxies. Fixture f = b._fixtureList; while (f != null) { Fixture f0 = f; f = f._next; if (DestructionListener != null) { DestructionListener.SayGoodbye(f0); } f0.Destroy(_contactManager._broadPhase); } b._fixtureList = null; b._fixtureCount = 0; // Remove world body list. if (b._prev != null) { b._prev._next = b._next; } if (b._next != null) { b._next._prev = b._prev; } if (b == _bodyList) { _bodyList = b._next; } --_bodyCount; }
// Broad-phase callback. internal void AddPair(Fixture proxyUserDataA, Fixture proxyUserDataB) { Fixture fixtureA = proxyUserDataA; Fixture fixtureB = proxyUserDataB; Body bodyA = fixtureA.GetBody(); Body bodyB = fixtureB.GetBody(); // Are the fixtures on the same body? if (bodyA == bodyB) { return; } // Are both bodies static? if (bodyA.IsStatic && bodyB.IsStatic) { return; } // Does a contact already exist? ContactEdge edge = bodyB.GetConactList(); while (edge != null) { if (edge.Other == bodyA) { Fixture fA = edge.Contact.GetFixtureA(); Fixture fB = edge.Contact.GetFixtureB(); if (fA == fixtureA && fB == fixtureB) { // A contact already exists. return; } if (fA == fixtureB && fB == fixtureA) { // A contact already exists. return; } } edge = edge.Next; } // Does a joint override collision? if (bodyB.IsConnected(bodyA)) { return; } // Check user filtering. if (ContactFilter.ShouldCollide(fixtureA, fixtureB) == false) { return; } // Call the factory. Contact c = Contact.Create(fixtureA, fixtureB); // Contact creation may swap fixtures. fixtureA = c.GetFixtureA(); fixtureB = c.GetFixtureB(); bodyA = fixtureA.GetBody(); bodyB = fixtureB.GetBody(); // Insert into the world. c._prev = null; c._next = _contactList; if (_contactList != null) { _contactList._prev = c; } _contactList = c; // Connect to island graph. // Connect to body A c._nodeA.Contact = c; c._nodeA.Other = bodyB; c._nodeA.Prev = null; c._nodeA.Next = bodyA._contactList; if (bodyA._contactList != null) { bodyA._contactList.Prev = c._nodeA; } bodyA._contactList = c._nodeA; // Connect to body B c._nodeB.Contact = c; c._nodeB.Other = bodyA; c._nodeB.Prev = null; c._nodeB.Next = bodyB._contactList; if (bodyB._contactList != null) { bodyB._contactList.Prev = c._nodeB; } bodyB._contactList = c._nodeB; ++_contactCount; }