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Diffstat (limited to 'src/3rdparty/Box2D/Dynamics/Contacts/b2Contact.h')
-rw-r--r-- | src/3rdparty/Box2D/Dynamics/Contacts/b2Contact.h | 349 |
1 files changed, 349 insertions, 0 deletions
diff --git a/src/3rdparty/Box2D/Dynamics/Contacts/b2Contact.h b/src/3rdparty/Box2D/Dynamics/Contacts/b2Contact.h new file mode 100644 index 0000000..df23d3c --- /dev/null +++ b/src/3rdparty/Box2D/Dynamics/Contacts/b2Contact.h @@ -0,0 +1,349 @@ +/* +* Copyright (c) 2006-2009 Erin Catto http://www.box2d.org +* +* 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_CONTACT_H +#define B2_CONTACT_H + +#include "Box2D/Common/b2Math.h" +#include "Box2D/Collision/b2Collision.h" +#include "Box2D/Collision/Shapes/b2Shape.h" +#include "Box2D/Dynamics/b2Fixture.h" + +class b2Body; +class b2Contact; +class b2Fixture; +class b2World; +class b2BlockAllocator; +class b2StackAllocator; +class b2ContactListener; + +/// Friction mixing law. The idea is to allow either fixture to drive the friction to zero. +/// For example, anything slides on ice. +inline float32 b2MixFriction(float32 friction1, float32 friction2) +{ + return b2Sqrt(friction1 * friction2); +} + +/// Restitution mixing law. The idea is allow for anything to bounce off an inelastic surface. +/// For example, a superball bounces on anything. +inline float32 b2MixRestitution(float32 restitution1, float32 restitution2) +{ + return restitution1 > restitution2 ? restitution1 : restitution2; +} + +typedef b2Contact* b2ContactCreateFcn( b2Fixture* fixtureA, int32 indexA, + b2Fixture* fixtureB, int32 indexB, + b2BlockAllocator* allocator); +typedef void b2ContactDestroyFcn(b2Contact* contact, b2BlockAllocator* allocator); + +struct b2ContactRegister +{ + b2ContactCreateFcn* createFcn; + b2ContactDestroyFcn* destroyFcn; + bool primary; +}; + +/// A contact edge is used to connect bodies and contacts together +/// in a contact graph where each body is a node and each contact +/// is an edge. A contact edge belongs to a doubly linked list +/// maintained in each attached body. Each contact has two contact +/// nodes, one for each attached body. +struct b2ContactEdge +{ + b2Body* other; ///< provides quick access to the other body attached. + b2Contact* contact; ///< the contact + b2ContactEdge* prev; ///< the previous contact edge in the body's contact list + b2ContactEdge* next; ///< the next contact edge in the body's contact list +}; + +/// The class manages contact between two shapes. A contact exists for each overlapping +/// AABB in the broad-phase (except if filtered). Therefore a contact object may exist +/// that has no contact points. +class b2Contact +{ +public: + + /// Get the contact manifold. Do not modify the manifold unless you understand the + /// internals of Box2D. + b2Manifold* GetManifold(); + const b2Manifold* GetManifold() const; + + /// Get the world manifold. + void GetWorldManifold(b2WorldManifold* worldManifold) const; + + /// Is this contact touching? + bool IsTouching() const; + + /// Enable/disable this contact. This can be used inside the pre-solve + /// contact listener. The contact is only disabled for the current + /// time step (or sub-step in continuous collisions). + void SetEnabled(bool flag); + + /// Has this contact been disabled? + bool IsEnabled() const; + + /// Get the next contact in the world's contact list. + b2Contact* GetNext(); + const b2Contact* GetNext() const; + + /// Get fixture A in this contact. + b2Fixture* GetFixtureA(); + const b2Fixture* GetFixtureA() const; + + /// Get the child primitive index for fixture A. + int32 GetChildIndexA() const; + + /// Get fixture B in this contact. + b2Fixture* GetFixtureB(); + const b2Fixture* GetFixtureB() const; + + /// Get the child primitive index for fixture B. + int32 GetChildIndexB() const; + + /// Override the default friction mixture. You can call this in b2ContactListener::PreSolve. + /// This value persists until set or reset. + void SetFriction(float32 friction); + + /// Get the friction. + float32 GetFriction() const; + + /// Reset the friction mixture to the default value. + void ResetFriction(); + + /// Override the default restitution mixture. You can call this in b2ContactListener::PreSolve. + /// The value persists until you set or reset. + void SetRestitution(float32 restitution); + + /// Get the restitution. + float32 GetRestitution() const; + + /// Reset the restitution to the default value. + void ResetRestitution(); + + /// Set the desired tangent speed for a conveyor belt behavior. In meters per second. + void SetTangentSpeed(float32 speed); + + /// Get the desired tangent speed. In meters per second. + float32 GetTangentSpeed() const; + + /// Evaluate this contact with your own manifold and transforms. + virtual void Evaluate(b2Manifold* manifold, const b2Transform& xfA, const b2Transform& xfB) = 0; + +protected: + friend class b2ContactManager; + friend class b2World; + friend class b2ContactSolver; + friend class b2Body; + friend class b2Fixture; + + // Flags stored in m_flags + enum + { + // Used when crawling contact graph when forming islands. + e_islandFlag = 0x0001, + + // Set when the shapes are touching. + e_touchingFlag = 0x0002, + + // This contact can be disabled (by user) + e_enabledFlag = 0x0004, + + // This contact needs filtering because a fixture filter was changed. + e_filterFlag = 0x0008, + + // This bullet contact had a TOI event + e_bulletHitFlag = 0x0010, + + // This contact has a valid TOI in m_toi + e_toiFlag = 0x0020 + }; + + /// Flag this contact for filtering. Filtering will occur the next time step. + void FlagForFiltering(); + + static void AddType(b2ContactCreateFcn* createFcn, b2ContactDestroyFcn* destroyFcn, + b2Shape::Type typeA, b2Shape::Type typeB); + static void InitializeRegisters(); + static b2Contact* Create(b2Fixture* fixtureA, int32 indexA, b2Fixture* fixtureB, int32 indexB, b2BlockAllocator* allocator); + static void Destroy(b2Contact* contact, b2Shape::Type typeA, b2Shape::Type typeB, b2BlockAllocator* allocator); + static void Destroy(b2Contact* contact, b2BlockAllocator* allocator); + + b2Contact() : m_fixtureA(nullptr), m_fixtureB(nullptr) {} + b2Contact(b2Fixture* fixtureA, int32 indexA, b2Fixture* fixtureB, int32 indexB); + virtual ~b2Contact() {} + + void Update(b2ContactListener* listener); + + static b2ContactRegister s_registers[b2Shape::e_typeCount][b2Shape::e_typeCount]; + static bool s_initialized; + + uint32 m_flags; + + // World pool and list pointers. + b2Contact* m_prev; + b2Contact* m_next; + + // Nodes for connecting bodies. + b2ContactEdge m_nodeA; + b2ContactEdge m_nodeB; + + b2Fixture* m_fixtureA; + b2Fixture* m_fixtureB; + + int32 m_indexA; + int32 m_indexB; + + b2Manifold m_manifold; + + int32 m_toiCount; + float32 m_toi; + + float32 m_friction; + float32 m_restitution; + + float32 m_tangentSpeed; +}; + +inline b2Manifold* b2Contact::GetManifold() +{ + return &m_manifold; +} + +inline const b2Manifold* b2Contact::GetManifold() const +{ + return &m_manifold; +} + +inline void b2Contact::GetWorldManifold(b2WorldManifold* worldManifold) const +{ + const b2Body* bodyA = m_fixtureA->GetBody(); + const b2Body* bodyB = m_fixtureB->GetBody(); + const b2Shape* shapeA = m_fixtureA->GetShape(); + const b2Shape* shapeB = m_fixtureB->GetShape(); + + worldManifold->Initialize(&m_manifold, bodyA->GetTransform(), shapeA->m_radius, bodyB->GetTransform(), shapeB->m_radius); +} + +inline void b2Contact::SetEnabled(bool flag) +{ + if (flag) + { + m_flags |= e_enabledFlag; + } + else + { + m_flags &= ~e_enabledFlag; + } +} + +inline bool b2Contact::IsEnabled() const +{ + return (m_flags & e_enabledFlag) == e_enabledFlag; +} + +inline bool b2Contact::IsTouching() const +{ + return (m_flags & e_touchingFlag) == e_touchingFlag; +} + +inline b2Contact* b2Contact::GetNext() +{ + return m_next; +} + +inline const b2Contact* b2Contact::GetNext() const +{ + return m_next; +} + +inline b2Fixture* b2Contact::GetFixtureA() +{ + return m_fixtureA; +} + +inline const b2Fixture* b2Contact::GetFixtureA() const +{ + return m_fixtureA; +} + +inline b2Fixture* b2Contact::GetFixtureB() +{ + return m_fixtureB; +} + +inline int32 b2Contact::GetChildIndexA() const +{ + return m_indexA; +} + +inline const b2Fixture* b2Contact::GetFixtureB() const +{ + return m_fixtureB; +} + +inline int32 b2Contact::GetChildIndexB() const +{ + return m_indexB; +} + +inline void b2Contact::FlagForFiltering() +{ + m_flags |= e_filterFlag; +} + +inline void b2Contact::SetFriction(float32 friction) +{ + m_friction = friction; +} + +inline float32 b2Contact::GetFriction() const +{ + return m_friction; +} + +inline void b2Contact::ResetFriction() +{ + m_friction = b2MixFriction(m_fixtureA->m_friction, m_fixtureB->m_friction); +} + +inline void b2Contact::SetRestitution(float32 restitution) +{ + m_restitution = restitution; +} + +inline float32 b2Contact::GetRestitution() const +{ + return m_restitution; +} + +inline void b2Contact::ResetRestitution() +{ + m_restitution = b2MixRestitution(m_fixtureA->m_restitution, m_fixtureB->m_restitution); +} + +inline void b2Contact::SetTangentSpeed(float32 speed) +{ + m_tangentSpeed = speed; +} + +inline float32 b2Contact::GetTangentSpeed() const +{ + return m_tangentSpeed; +} + +#endif |