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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.
 */
 
 #ifndef B2_FIXTURE_H
 #define B2_FIXTURE_H
 
 #include <Box2D/Dynamics/b2Body.h>
 #include <Box2D/Collision/b2Collision.h>
 #include <Box2D/Collision/Shapes/b2Shape.h>
 
 class b2BlockAllocator;
 class b2Body;
 class b2BroadPhase;
 class b2Fixture;
 
 /// This holds contact filtering data.
 struct b2Filter
 {
     /// The collision category bits. Normally you would just set one bit.
     uint16 categoryBits;
 
     /// The collision mask bits. This states the categories that this
     /// shape would accept for collision.
     uint16 maskBits;
 
     /// Collision groups allow a certain group of objects to never collide (negative)
     /// or always collide (positive). Zero means no collision group. Non-zero group
     /// filtering always wins against the mask bits.
     int16 groupIndex;
 };
 
 /// A fixture definition is used to create a fixture. This class defines an
 /// abstract fixture definition. You can reuse fixture definitions safely.
 struct b2FixtureDef
 {
     /// The constructor sets the default fixture definition values.
     b2FixtureDef()
     {
         shape = NULL;
         userData = NULL;
         friction = 0.2f;
         restitution = 0.0f;
         density = 0.0f;
         filter.categoryBits = 0x0001;
         filter.maskBits = 0xFFFF;
         filter.groupIndex = 0;
         isSensor = false;
     }
 
     virtual ~b2FixtureDef() {}
 
     /// The shape, this must be set. The shape will be cloned, so you
     /// can create the shape on the stack.
     const b2Shape* shape;
 
     /// Use this to store application specific fixture data.
     void* userData;
 
     /// The friction coefficient, usually in the range [0,1].
     qreal friction;
 
     /// The restitution (elasticity) usually in the range [0,1].
     qreal restitution;
 
     /// The density, usually in kg/m^2.
     qreal density;
 
     /// A sensor shape collects contact information but never generates a collision
     /// response.
     bool isSensor;
 
     /// Contact filtering data.
     b2Filter filter;
 };
 
 /// This proxy is used internally to connect fixtures to the broad-phase.
 struct b2FixtureProxy
 {
     b2AABB aabb;
     b2Fixture* fixture;
     int32 childIndex;
     int32 proxyId;
 };
 
 /// A fixture is used to attach a shape to a body for collision detection. A fixture
 /// inherits its transform from its parent. Fixtures hold additional non-geometric data
 /// such as friction, collision filters, etc.
 /// Fixtures are created via b2Body::CreateFixture.
 /// @warning you cannot reuse fixtures.
 class b2Fixture
 {
 public:
     /// Get the type of the child shape. You can use this to down cast to the concrete shape.
     /// @return the shape type.
     b2Shape::Type GetType() const;
 
     /// Get the child shape. You can modify the child shape, however you should not change the
     /// number of vertices because this will crash some collision caching mechanisms.
     /// Manipulating the shape may lead to non-physical behavior.
     b2Shape* GetShape();
     const b2Shape* GetShape() const;
 
     /// Set if this fixture is a sensor.
     void SetSensor(bool sensor);
 
     /// Is this fixture a sensor (non-solid)?
     /// @return the true if the shape is a sensor.
     bool IsSensor() const;
 
     /// Set the contact filtering data. This will not update contacts until the next time
     /// step when either parent body is active and awake.
     void SetFilterData(const b2Filter& filter);
 
     /// Get the contact filtering data.
     const b2Filter& GetFilterData() const;
 
     /// Get the parent body of this fixture. This is NULL if the fixture is not attached.
     /// @return the parent body.
     b2Body* GetBody();
     const b2Body* GetBody() const;
 
     /// Get the next fixture in the parent body's fixture list.
     /// @return the next shape.
     b2Fixture* GetNext();
     const b2Fixture* GetNext() const;
 
     /// Get the user data that was assigned in the fixture definition. Use this to
     /// store your application specific data.
     void* GetUserData() const;
 
     /// Set the user data. Use this to store your application specific data.
     void SetUserData(void* data);
 
     /// Test a point for containment in this fixture.
     /// @param p a point in world coordinates.
     bool TestPoint(const b2Vec2& p) const;
 
     /// Cast a ray against this shape.
     /// @param output the ray-cast results.
     /// @param input the ray-cast input parameters.
     bool RayCast(b2RayCastOutput* output, const b2RayCastInput& input, int32 childIndex) const;
 
     /// Get the mass data for this fixture. The mass data is based on the density and
     /// the shape. The rotational inertia is about the shape's origin. This operation
     /// may be expensive.
     void GetMassData(b2MassData* massData) const;
 
     /// Set the density of this fixture. This will _not_ automatically adjust the mass
     /// of the body. You must call b2Body::ResetMassData to update the body's mass.
     void SetDensity(qreal density);
 
     /// Get the density of this fixture.
     qreal GetDensity() const;
 
     /// Get the coefficient of friction.
     qreal GetFriction() const;
 
     /// Set the coefficient of friction. This will immediately update the mixed friction
     /// on all associated contacts.
     void SetFriction(qreal friction);
 
     /// Get the coefficient of restitution.
     qreal GetRestitution() const;
 
     /// Set the coefficient of restitution. This will immediately update the mixed restitution
     /// on all associated contacts.
     void SetRestitution(qreal restitution);
 
     /// Get the fixture's AABB. This AABB may be enlarge and/or stale.
     /// If you need a more accurate AABB, compute it using the shape and
     /// the body transform.
     const b2AABB& GetAABB(int32 childIndex) const;
 
 protected:
 
     friend class b2Body;
     friend class b2World;
     friend class b2Contact;
     friend class b2ContactManager;
 
     b2Fixture();
 
     // We need separation create/destroy functions from the constructor/destructor because
     // the destructor cannot access the allocator (no destructor arguments allowed by C++).
     void Create(b2BlockAllocator* allocator, b2Body* body, const b2FixtureDef* def);
     void Destroy(b2BlockAllocator* allocator);
 
     // These support body activation/deactivation.
     void CreateProxies(b2BroadPhase* broadPhase, const b2Transform& xf);
     void DestroyProxies(b2BroadPhase* broadPhase);
 
     void Synchronize(b2BroadPhase* broadPhase, const b2Transform& xf1, const b2Transform& xf2);
 
     qreal m_density;
 
     b2Fixture* m_next;
     b2Body* m_body;
 
     b2Shape* m_shape;
 
     qreal m_friction;
     qreal m_restitution;
 
     b2FixtureProxy* m_proxies;
     int32 m_proxyCount;
 
     b2Filter m_filter;
 
     bool m_isSensor;
 
     void* m_userData;
 };
 
 inline b2Shape::Type b2Fixture::GetType() const
 {
     return m_shape->GetType();
 }
 
 inline b2Shape* b2Fixture::GetShape()
 {
     return m_shape;
 }
 
 inline const b2Shape* b2Fixture::GetShape() const
 {
     return m_shape;
 }
 
 inline bool b2Fixture::IsSensor() const
 {
     return m_isSensor;
 }
 
 inline const b2Filter& b2Fixture::GetFilterData() const
 {
     return m_filter;
 }
 
 inline void* b2Fixture::GetUserData() const
 {
     return m_userData;
 }
 
 inline void b2Fixture::SetUserData(void* data)
 {
     m_userData = data;
 }
 
 inline b2Body* b2Fixture::GetBody()
 {
     return m_body;
 }
 
 inline const b2Body* b2Fixture::GetBody() const
 {
     return m_body;
 }
 
 inline b2Fixture* b2Fixture::GetNext()
 {
     return m_next;
 }
 
 inline const b2Fixture* b2Fixture::GetNext() const
 {
     return m_next;
 }
 
 inline void b2Fixture::SetDensity(qreal density)
 {
     b2Assert(b2IsValid(density) && density >= 0.0f);
     m_density = density;
 }
 
 inline qreal b2Fixture::GetDensity() const
 {
     return m_density;
 }
 
 inline qreal b2Fixture::GetFriction() const
 {
     return m_friction;
 }
 
 inline void b2Fixture::SetFriction(qreal friction)
 {
     m_friction = friction;
 }
 
 inline qreal b2Fixture::GetRestitution() const
 {
     return m_restitution;
 }
 
 inline void b2Fixture::SetRestitution(qreal restitution)
 {
     m_restitution = restitution;
 }
 
 inline bool b2Fixture::TestPoint(const b2Vec2& p) const
 {
     return m_shape->TestPoint(m_body->GetTransform(), p);
 }
 
 inline bool b2Fixture::RayCast(b2RayCastOutput* output, const b2RayCastInput& input, int32 childIndex) const
 {
     return m_shape->RayCast(output, input, m_body->GetTransform(), childIndex);
 }
 
 inline void b2Fixture::GetMassData(b2MassData* massData) const
 {
     m_shape->ComputeMass(massData, m_density);
 }
 
 inline const b2AABB& b2Fixture::GetAABB(int32 childIndex) const
 {
     b2Assert(0 <= childIndex && childIndex < m_proxyCount);
     return m_proxies[childIndex].aabb;
 }
 
 #endif