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 /*
 * 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/b2Fixture.h>
 #include <Box2D/Dynamics/Contacts/b2Contact.h>
 #include <Box2D/Collision/Shapes/b2CircleShape.h>
 #include <Box2D/Collision/Shapes/b2EdgeShape.h>
 #include <Box2D/Collision/Shapes/b2PolygonShape.h>
 #include <Box2D/Collision/Shapes/b2LoopShape.h>
 #include <Box2D/Collision/b2BroadPhase.h>
 #include <Box2D/Common/b2BlockAllocator.h>
 
 b2Fixture::b2Fixture()
 {
     m_userData = NULL;
     m_body = NULL;
     m_next = NULL;
     m_proxies = NULL;
     m_proxyCount = 0;
     m_shape = NULL;
     m_density = 0.0f;
 }
 
 void b2Fixture::Create(b2BlockAllocator* allocator, b2Body* body, const b2FixtureDef* def)
 {
     m_userData = def->userData;
     m_friction = def->friction;
     m_restitution = def->restitution;
 
     m_body = body;
     m_next = NULL;
 
     m_filter = def->filter;
 
     m_isSensor = def->isSensor;
 
     m_shape = def->shape->Clone(allocator);
 
     // Reserve proxy space
     int32 childCount = m_shape->GetChildCount();
     m_proxies = (b2FixtureProxy*)allocator->Allocate(childCount * sizeof(b2FixtureProxy));
     for (int32 i = 0; i < childCount; ++i)
     {
         m_proxies[i].fixture = NULL;
         m_proxies[i].proxyId = b2BroadPhase::e_nullProxy;
     }
     m_proxyCount = 0;
 
     m_density = def->density;
 }
 
 void b2Fixture::Destroy(b2BlockAllocator* allocator)
 {
     // The proxies must be destroyed before calling this.
     b2Assert(m_proxyCount == 0);
 
     // Free the proxy array.
     int32 childCount = m_shape->GetChildCount();
     allocator->Free(m_proxies, childCount * sizeof(b2FixtureProxy));
     m_proxies = NULL;
 
     // Free the child shape.
     switch (m_shape->m_type)
     {
     case b2Shape::e_circle:
         {
             b2CircleShape* s = (b2CircleShape*)m_shape;
             s->~b2CircleShape();
             allocator->Free(s, sizeof(b2CircleShape));
         }
         break;
 
     case b2Shape::e_edge:
         {
             b2EdgeShape* s = (b2EdgeShape*)m_shape;
             s->~b2EdgeShape();
             allocator->Free(s, sizeof(b2EdgeShape));
         }
         break;
 
     case b2Shape::e_polygon:
         {
             b2PolygonShape* s = (b2PolygonShape*)m_shape;
             s->~b2PolygonShape();
             allocator->Free(s, sizeof(b2PolygonShape));
         }
         break;
 
     case b2Shape::e_loop:
         {
             b2LoopShape* s = (b2LoopShape*)m_shape;
             s->~b2LoopShape();
             allocator->Free(s, sizeof(b2LoopShape));
         }
         break;
 
     default:
         b2Assert(false);
         break;
     }
 
     m_shape = NULL;
 }
 
 void b2Fixture::CreateProxies(b2BroadPhase* broadPhase, const b2Transform& xf)
 {
     b2Assert(m_proxyCount == 0);
 
     // Create proxies in the broad-phase.
     m_proxyCount = m_shape->GetChildCount();
 
     for (int32 i = 0; i < m_proxyCount; ++i)
     {
         b2FixtureProxy* proxy = m_proxies + i;
         m_shape->ComputeAABB(&proxy->aabb, xf, i);
         proxy->proxyId = broadPhase->CreateProxy(proxy->aabb, proxy);
         proxy->fixture = this;
         proxy->childIndex = i;
     }
 }
 
 void b2Fixture::DestroyProxies(b2BroadPhase* broadPhase)
 {
     // Destroy proxies in the broad-phase.
     for (int32 i = 0; i < m_proxyCount; ++i)
     {
         b2FixtureProxy* proxy = m_proxies + i;
         broadPhase->DestroyProxy(proxy->proxyId);
         proxy->proxyId = b2BroadPhase::e_nullProxy;
     }
 
     m_proxyCount = 0;
 }
 
 void b2Fixture::Synchronize(b2BroadPhase* broadPhase, const b2Transform& transform1, const b2Transform& transform2)
 {
     if (m_proxyCount == 0)
     {   
         return;
     }
 
     for (int32 i = 0; i < m_proxyCount; ++i)
     {
         b2FixtureProxy* proxy = m_proxies + i;
 
         // Compute an AABB that covers the swept shape (may miss some rotation effect).
         b2AABB aabb1, aabb2;
         m_shape->ComputeAABB(&aabb1, transform1, proxy->childIndex);
         m_shape->ComputeAABB(&aabb2, transform2, proxy->childIndex);
     
         proxy->aabb.Combine(aabb1, aabb2);
 
         b2Vec2 displacement = transform2.position - transform1.position;
 
         broadPhase->MoveProxy(proxy->proxyId, proxy->aabb, displacement);
     }
 }
 
 void b2Fixture::SetFilterData(const b2Filter& filter)
 {
     m_filter = filter;
 
     if (m_body == NULL)
     {
         return;
     }
 
     // Flag associated contacts for filtering.
     b2ContactEdge* edge = m_body->GetContactList();
     while (edge)
     {
         b2Contact* contact = edge->contact;
         b2Fixture* fixtureA = contact->GetFixtureA();
         b2Fixture* fixtureB = contact->GetFixtureB();
         if (fixtureA == this || fixtureB == this)
         {
             contact->FlagForFiltering();
         }
 
         edge = edge->next;
     }
 }
 
 void b2Fixture::SetSensor(bool sensor)
 {
     m_isSensor = sensor;
 }