/// Destroy a fixture. This removes the fixture from the broad-phase and
/// destroys all contacts associated with this fixture. This will
/// automatically adjust the mass of the body if the body is dynamic and the
/// fixture has positive density.
/// All fixtures attached to a body are implicitly destroyed when the body is destroyed.
/// @param fixture the fixture to be removed.
/// @warning This function is locked during callbacks.
public void DestroyFixture(Fixture fixture)
{
Debug.Assert(_world.IsLocked == false);
if (_world.IsLocked == true)
{
return;
}
Debug.Assert(fixture._body == this);
// Remove the fixture from this body's singly linked list.
Debug.Assert(_fixtureCount > 0);
Fixture node = _fixtureList;
bool found = false;
while (node != null)
{
if (node == fixture)
{
_fixtureList = fixture._next;
found = true;
break;
}
node = node._next;
}
// You tried to remove a shape that is not attached to this body.
Debug.Assert(found);
// Destroy any contacts associated with the fixture.
ContactEdge edge = _contactList;
while (edge != null)
{
Contact c = edge.Contact;
edge = edge.Next;
Fixture fixtureA = c.GetFixtureA();
Fixture fixtureB = c.GetFixtureB();
if (fixture == fixtureA || fixture == fixtureB)
{
// This destroys the contact and removes it from
// this body's contact list.
_world._contactManager.Destroy(c);
}
}
if ((_flags & BodyFlags.Active) == BodyFlags.Active)
{
Debug.Assert(fixture._proxyId != BroadPhase.NullProxy);
BroadPhase broadPhase = _world._contactManager._broadPhase;
fixture.DestroyProxies(broadPhase);
}
fixture.Destroy();
fixture._body = null;
fixture._next = null;
--_fixtureCount;
ResetMassData();
}
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 constraint 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 (!b.IsAwake() || !b.IsActive())
{
continue;
}
if (b.GetType() == BodyType.Static)
{
continue;
}
// Update fixtures (for broad-phase).
b.SynchronizeFixtures();
}
// Look for new contacts.
_contactManager.FindNewContacts();
}
// Advance a dynamic body to its first time of contact
// and adjust the position to ensure clearance.
void SolveTOI(Body body)
{
// Find the minimum contact.
Contact toiContact = null;
float toi = 1.0f;
bool found;
int count;
int iter = 0;
bool bullet = body.IsBullet;
// Iterate until all contacts agree on the minimum TOI. We have
// to iterate because the TOI algorithm may skip some intermediate
// collisions when objects rotate through each other.
do
{
count = 0;
found = false;
for (ContactEdge ce = body._contactList; ce != null; ce = ce.Next)
{
Body other = ce.Other;
BodyType type = other.GetType();
// Only bullets perform TOI with dynamic bodies.
if (bullet == true)
{
// Bullets only perform TOI with bodies that have their TOI resolved.
if ((other._flags & BodyFlags.Toi) == 0)
{
continue;
}
}
else if (type == BodyType.Dynamic)
{
continue;
}
// Check for a disabled contact.
Contact contact = ce.Contact;
if (contact.IsEnabled() == false)
{
continue;
}
// Prevent infinite looping.
if (contact._toiCount > 10)
{
continue;
}
Fixture fixtureA = contact._fixtureA;
Fixture fixtureB = contact._fixtureB;
// Cull sensors.
if (fixtureA.IsSensor() || fixtureB.IsSensor())
{
continue;
}
Body bodyA = fixtureA._body;
Body bodyB = fixtureB._body;
// Compute the time of impact in interval [0, minTOI]
TOIInput input = new TOIInput();
input.proxyA.Set(fixtureA.GetShape());
input.proxyB.Set(fixtureB.GetShape());
input.sweepA = bodyA._sweep;
input.sweepB = bodyB._sweep;
input.tMax = toi;
TOIOutput output;
TimeOfImpact.CalculateTimeOfImpact(out output, ref input);
if (output.State == TOIOutputState.Touching && output.t < toi)
{
toiContact = contact;
toi = output.t;
found = true;
}
++count;
}
++iter;
} while (found && count > 1 && iter < 50);
if (toiContact == null)
{
return;
}
// Advance the body to its safe time.
Sweep backup = body._sweep;
body.Advance(toi);
++toiContact._toiCount;
// Update all the valid contacts on this body and build a contact island.
count = 0;
for (ContactEdge ce = body._contactList; (ce != null) && (count < Settings.b2_maxTOIContacts); ce = ce.Next)
{
Body other = ce.Other;
BodyType type = other.GetType();
// Only perform correction with static bodies, so the
// body won't get pushed out of the world.
if (type != BodyType.Static)
{
continue;
}
// Check for a disabled contact.
Contact contact = ce.Contact;
if (contact.IsEnabled() == false)
{
continue;
}
Fixture fixtureA = contact._fixtureA;
Fixture fixtureB = contact._fixtureB;
// Cull sensors.
if (fixtureA.IsSensor() || fixtureB.IsSensor())
{
continue;
}
// The contact likely has some new contact points. The listener
// gives the user a chance to disable the contact;
contact.Update(_contactManager.ContactListener);
// Did the user disable the contact?
if (contact.IsEnabled() == false)
{
if (contact == toiContact)
{
// Restore the body's sweep.
body._sweep = backup;
body.SynchronizeTransform();
// Recurse because the TOI has been invalidated.
SolveTOI(body);
return;
}
// Skip this contact.
continue;
}
if (contact.IsTouching() == false)
{
continue;
}
_toiContacts[count] = contact;
++count;
}
// Reduce the TOI body's overlap with the contact island.
_toiSolver.Initialize(_toiContacts, count, body);
const float k_toiBaumgarte = 0.75f;
//bool solved = false;
for (int i = 0; i < 20; ++i)
{
bool contactsOkay = _toiSolver.Solve(k_toiBaumgarte);
if (contactsOkay)
{
//solved = true;
break;
}
}
}
/// 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;
}
}
}
/// 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.bodyA;
Body bodyB = def.bodyB;
bool staticA = bodyA.GetType() == BodyType.Static;
bool staticB = bodyB.GetType() == BodyType.Static;
// If the joint prevents collisions, then flag any contacts for filtering.
if (def.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;
}
}
// 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.DestroyProxy(_contactManager._broadPhase);
f0.Destroy();
}
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;
}
/// <summary>
/// Set the active state of the body. An inactive body is not
/// simulated and cannot be collided with or woken up.
/// If you pass a flag of true, all fixtures will be added to the
/// broad-phase.
/// If you pass a flag of false, all fixtures will be removed from
/// the broad-phase and all contacts will be destroyed.
/// Fixtures and joints are otherwise unaffected. You may continue
/// to create/destroy fixtures and joints on inactive bodies.
/// Fixtures on an inactive body are implicitly inactive and will
/// not participate in collisions, ray-casts, or queries.
/// Joints connected to an inactive body are implicitly inactive.
/// An inactive body is still owned by a b2World object and remains
/// in the body list.
/// </summary>
/// <param name="flag"></param>
public void SetActive(bool flag)
{
if (flag == IsActive())
{
return;
}
if (flag)
{
_flags |= BodyFlags.Active;
// Create all proxies.
BroadPhase broadPhase = _world._contactManager._broadPhase;
for (Fixture f = _fixtureList; f != null; f = f._next)
{
f.CreateProxy(broadPhase, ref _xf);
}
// Contacts are created the next time step.
}
else
{
_flags &= ~BodyFlags.Active;
// Destroy all proxies.
BroadPhase broadPhase = _world._contactManager._broadPhase;
for (Fixture f = _fixtureList; f != null; f = f._next)
{
f.DestroyProxy(broadPhase);
}
// Destroy the attached contacts.
ContactEdge ce = _contactList;
while (ce != null)
{
ContactEdge ce0 = ce;
ce = ce.Next;
_world._contactManager.Destroy(ce0.Contact);
}
_contactList = null;
}
}
// Broad-phase callback.
internal void AddPair(FixtureProxy proxyA, FixtureProxy proxyB)
{
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;
}
// Does a contact already exist?
ContactEdge edge = bodyB.GetContactList();
while (edge != null)
{
if (edge.Other == bodyA)
{
Fixture fA = edge.Contact.GetFixtureA();
Fixture fB = edge.Contact.GetFixtureB();
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;
}
}
edge = edge.Next;
}
// Does a joint override collision? Is at least one body dynamic?
if (bodyB.ShouldCollide(bodyA) == false)
{
return;
}
// Check user filtering.
if (ContactFilter != null && ContactFilter.ShouldCollide(fixtureA, fixtureB) == false)
{
return;
}
// Call the factory.
Contact c = Contact.Create(fixtureA, indexA, fixtureB, indexB);
// Contact creation may swap fixtures.
fixtureA = c.GetFixtureA();
fixtureB = c.GetFixtureB();
indexA = c.GetChildIndexA();
indexB = c.GetChildIndexB();
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;
}