知易源码008+中文详细注释

/* * Copyright (c) 2006-2009 Erin Catto http://www.gphysics.com * * This software is provided 'as-is', without any express or implied * warranty. In no event will the authors be held liable for any damages * arising from the use of this software. * Permission is granted to anyone to use this software for any purpose, * including commercial applications, and to alter it and redistribute it * freely, subject to the following restrictions: * 1. The origin of this software must not be misrepresented; you must not * claim that you wrote the original software. If you use this software * in a product, an acknowledgment in the product documentation would be * appreciated but is not required. * 2. Altered source versions must be plainly marked as such, and must not be * misrepresented as being the original software. * 3. This notice may not be removed or altered from any source distribution. */ #include <Box2D/Dynamics/b2World.h> #include <Box2D/Dynamics/b2Body.h> #include <Box2D/Dynamics/b2Fixture.h> #include <Box2D/Dynamics/b2Island.h> #include <Box2D/Dynamics/Joints/b2PulleyJoint.h> #include <Box2D/Dynamics/Contacts/b2Contact.h> #include <Box2D/Dynamics/Contacts/b2ContactSolver.h> #include <Box2D/Dynamics/Contacts/b2TOISolver.h> #include <Box2D/Collision/b2Collision.h> #include <Box2D/Collision/b2BroadPhase.h> #include <Box2D/Collision/Shapes/b2CircleShape.h> #include <Box2D/Collision/Shapes/b2PolygonShape.h> #include <Box2D/Collision/b2TimeOfImpact.h> #include <new> b2World::b2World(const b2Vec2& gravity, bool doSleep) { m_destructionListener = NULL; m_debugDraw = NULL; m_bodyList = NULL; m_jointList = NULL; m_bodyCount = 0; m_jointCount = 0; m_warmStarting = true; m_continuousPhysics = true; m_allowSleep = doSleep; m_gravity = gravity; m_flags = e_clearForces; m_inv_dt0 = 0.0f; m_contactManager.m_allocator = &m_blockAllocator; } b2World::~b2World() { } void b2World::SetDestructionListener(b2DestructionListener* listener) { m_destructionListener = listener; } void b2World::SetContactFilter(b2ContactFilter* filter) { m_contactManager.m_contactFilter = filter; } void b2World::SetContactListener(b2ContactListener* listener) { m_contactManager.m_contactListener = listener; } void b2World::SetDebugDraw(b2DebugDraw* debugDraw) { m_debugDraw = debugDraw; } b2Body* b2World::CreateBody(const b2BodyDef* def) { b2Assert(IsLocked() == false); if (IsLocked()) { return NULL; } void* mem = m_blockAllocator.Allocate(sizeof(b2Body)); b2Body* b = new (mem) b2Body(def, this); // Add to world doubly linked list. b->m_prev = NULL; b->m_next = m_bodyList; if (m_bodyList) { m_bodyList->m_prev = b; } m_bodyList = b; ++m_bodyCount; return b; } void b2World::DestroyBody(b2Body* b) { b2Assert(m_bodyCount > 0); b2Assert(IsLocked() == false); if (IsLocked()) { return; } // Delete the attached joints. b2JointEdge* je = b->m_jointList; while (je) { b2JointEdge* je0 = je; je = je->next; if (m_destructionListener) { m_destructionListener->SayGoodbye(je0->joint); } DestroyJoint(je0->joint); } b->m_jointList = NULL; // Delete the attached contacts. b2ContactEdge* ce = b->m_contactList; while (ce) { b2ContactEdge* ce0 = ce; ce = ce->next; m_contactManager.Destroy(ce0->contact); } b->m_contactList = NULL; // Delete the attached fixtures. This destroys broad-phase proxies. b2Fixture* f = b->m_fixtureList; while (f) { b2Fixture* f0 = f; f = f->m_next; if (m_destructionListener) { m_destructionListener->SayGoodbye(f0); } f0->DestroyProxy(&m_contactManager.m_broadPhase); f0->Destroy(&m_blockAllocator); f0->~b2Fixture(); m_blockAllocator.Free(f0, sizeof(b2Fixture)); } b->m_fixtureList = NULL; b->m_fixtureCount = 0; // Remove world body list. if (b->m_prev) { b->m_prev->m_next = b->m_next; } if (b->m_next) { b->m_next->m_prev = b->m_prev; } if (b == m_bodyList) { m_bodyList = b->m_next; } --m_bodyCount; b->~b2Body(); m_blockAllocator.Free(b, sizeof(b2Body)); } b2Joint* b2World::CreateJoint(const b2JointDef* def) { b2Assert(IsLocked() == false); if (IsLocked()) { return NULL; } b2Joint* j = b2Joint::Create(def, &m_blockAllocator); // Connect to the world list. j->m_prev = NULL; j->m_next = m_jointList; if (m_jointList) { m_jointList->m_prev = j; } m_jointList = j; ++m_jointCount; // Connect to the bodies' doubly linked lists. j->m_edgeA.joint = j; j->m_edgeA.other = j->m_bodyB; j->m_edgeA.prev = NULL; j->m_edgeA.next = j->m_bodyA->m_jointList; if (j->m_bodyA->m_jointList) j->m_bodyA->m_jointList->prev = &j->m_edgeA; j->m_bodyA->m_jointList = &j->m_edgeA; j->m_edgeB.joint = j; j->m_edgeB.other = j->m_bodyA; j->m_edgeB.prev = NULL; j->m_edgeB.next = j->m_bodyB->m_jointList; if (j->m_bodyB->m_jointList) j->m_bodyB->m_jointList->prev = &j->m_edgeB; j->m_bodyB->m_jointList = &j->m_edgeB; b2Body* bodyA = def->bodyA; b2Body* bodyB = def->bodyB; // If the joint prevents collisions, then flag any contacts for filtering. if (def->collideConnected == false) { b2ContactEdge* edge = bodyB->GetContactList(); while (edge) { 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; } void b2World::DestroyJoint(b2Joint* j) { b2Assert(IsLocked() == false); if (IsLocked()) { return; } bool collideConnected = j->m_collideConnected; // Remove from the doubly linked list. if (j->m_prev) { j->m_prev->m_next = j->m_next; } if (j->m_next) { j->m_next->m_prev = j->m_prev; } if (j == m_jointList) { m_jointList = j->m_next; } // Disconnect from island graph. b2Body* bodyA = j->m_bodyA; b2Body* bodyB = j->m_bodyB; // Wake up connected bodies. bodyA->SetAwake(true); bodyB->SetAwake(true); // Remove from body 1. if (j->m_edgeA.prev) { j->m_edgeA.prev->next = j->m_edgeA.next; } if (j->m_edgeA.next) { j->m_edgeA.next->prev = j->m_edgeA.prev; } if (&j->m_edgeA == bodyA->m_jointList) { bodyA->m_jointList = j->m_edgeA.next; } j->m_edgeA.prev = NULL; j->m_edgeA.next = NULL; // Remove from body 2 if (j->m_edgeB.prev) { j->m_edgeB.prev->next = j->m_edgeB.next; } if (j->m_edgeB.next) { j->m_edgeB.next->prev = j->m_edgeB.prev; } if (&j->m_edgeB == bodyB->m_jointList) { bodyB->m_jointList = j->m_edgeB.next; } j->m_edgeB.prev = NULL; j->m_edgeB.next = NULL; b2Joint::Destroy(j, &m_blockAllocator); b2Assert(m_jointCount > 0); --m_jointCount; // If the joint prevents collisions, then flag any contacts for filtering. if (collideConnected == false) { b2ContactEdge* edge = bodyB->GetContactList(); while (edge) { 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; } } } // Find islands, integrate and solve constraints, solve position constraints void b2World::Solve(const b2TimeStep& step) { // Size the island for the worst case. b2Island island(m_bodyCount, m_contactManager.m_contactCount, m_jointCount, &m_stackAllocator, m_contactManager.m_contactListener); // Clear all the island flags. for (b2Body* b = m_bodyList; b; b = b->m_next) { b->m_flags &= ~b2Body::e_islandFlag; } for (b2Contact* c = m_contactManager.m_contactList; c; c = c->m_next) { c->m_flags &= ~b2Contact::e_islandFlag; } for (b2Joint* j = m_jointList; j; j = j->m_next) { j->m_islandFlag = false; } // Build and simulate all awake islands. int32 stackSize = m_bodyCount; b2Body** stack = (b2Body**)m_stackAllocator.Allocate(stackSize * sizeof(b2Body*)); for (b2Body* seed = m_bodyList; seed; seed = seed->m_next) { if (seed->m_flags & b2Body::e_islandFlag) { continue; } if (seed->IsAw