// Broad-phase callback. private void AddPair(ref FixtureProxy proxyA, ref FixtureProxy proxyB) { Fixture fixtureA = proxyA.Fixture; Fixture fixtureB = proxyB.Fixture; int indexA = proxyA.ChildIndex; int indexB = proxyB.ChildIndex; Body bodyA = fixtureA.Body; Body bodyB = fixtureB.Body; // Are the fixtures on the same body? if (bodyA == bodyB) { return; } // Does a contact already exist? ContactEdge edge = bodyB.ContactList; while (edge != null) { if (edge.Other == bodyA) { Fixture fA = edge.Contact.FixtureA; Fixture fB = edge.Contact.FixtureB; int iA = edge.Contact.ChildIndexA; int iB = edge.Contact.ChildIndexB; 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 default filter if (ShouldCollide(fixtureA, fixtureB) == false) { return; } // Check user filtering. if (ContactFilter != null && ContactFilter(fixtureA, fixtureB) == false) { return; } //FPE feature: BeforeCollision delegate if (fixtureA.RaiseBeforeCollision(fixtureA, fixtureB) == false) { return; } if (fixtureB.RaiseBeforeCollision(fixtureB, fixtureA) == 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; bodyA = fixtureA.Body; bodyB = fixtureB.Body; // Insert into the world. ContactList.Add(c); #if USE_ACTIVE_CONTACT_SET ActiveContacts.Add(c); #endif // 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; // Wake up the bodies if (fixtureA.IsSensor == false && fixtureB.IsSensor == false) { bodyA.Awake = true; bodyB.Awake = true; } }