Box2D  2.2.1
A 2D Physics Engine for Games
b2Joint.h
00001 /*
00002 * Copyright (c) 2006-2007 Erin Catto http://www.box2d.org
00003 *
00004 * This software is provided 'as-is', without any express or implied
00005 * warranty.  In no event will the authors be held liable for any damages
00006 * arising from the use of this software.
00007 * Permission is granted to anyone to use this software for any purpose,
00008 * including commercial applications, and to alter it and redistribute it
00009 * freely, subject to the following restrictions:
00010 * 1. The origin of this software must not be misrepresented; you must not
00011 * claim that you wrote the original software. If you use this software
00012 * in a product, an acknowledgment in the product documentation would be
00013 * appreciated but is not required.
00014 * 2. Altered source versions must be plainly marked as such, and must not be
00015 * misrepresented as being the original software.
00016 * 3. This notice may not be removed or altered from any source distribution.
00017 */
00018 
00019 #ifndef B2_JOINT_H
00020 #define B2_JOINT_H
00021 
00022 #include <Box2D/Common/b2Math.h>
00023 
00024 class b2Body;
00025 class b2Joint;
00026 struct b2SolverData;
00027 class b2BlockAllocator;
00028 
00029 enum b2JointType
00030 {
00031         e_unknownJoint,
00032         e_revoluteJoint,
00033         e_prismaticJoint,
00034         e_distanceJoint,
00035         e_pulleyJoint,
00036         e_mouseJoint,
00037         e_gearJoint,
00038         e_wheelJoint,
00039     e_weldJoint,
00040         e_frictionJoint,
00041         e_ropeJoint
00042 };
00043 
00044 enum b2LimitState
00045 {
00046         e_inactiveLimit,
00047         e_atLowerLimit,
00048         e_atUpperLimit,
00049         e_equalLimits
00050 };
00051 
00052 struct b2Jacobian
00053 {
00054         b2Vec2 linear;
00055         float32 angularA;
00056         float32 angularB;
00057 };
00058 
00064 struct b2JointEdge
00065 {
00066         b2Body* other;                  
00067         b2Joint* joint;                 
00068         b2JointEdge* prev;              
00069         b2JointEdge* next;              
00070 };
00071 
00073 struct b2JointDef
00074 {
00075         b2JointDef()
00076         {
00077                 type = e_unknownJoint;
00078                 userData = NULL;
00079                 bodyA = NULL;
00080                 bodyB = NULL;
00081                 collideConnected = false;
00082         }
00083 
00085         b2JointType type;
00086 
00088         void* userData;
00089 
00091         b2Body* bodyA;
00092 
00094         b2Body* bodyB;
00095 
00097         bool collideConnected;
00098 };
00099 
00102 class b2Joint
00103 {
00104 public:
00105 
00107         b2JointType GetType() const;
00108 
00110         b2Body* GetBodyA();
00111 
00113         b2Body* GetBodyB();
00114 
00116         virtual b2Vec2 GetAnchorA() const = 0;
00117 
00119         virtual b2Vec2 GetAnchorB() const = 0;
00120 
00122         virtual b2Vec2 GetReactionForce(float32 inv_dt) const = 0;
00123 
00125         virtual float32 GetReactionTorque(float32 inv_dt) const = 0;
00126 
00128         b2Joint* GetNext();
00129         const b2Joint* GetNext() const;
00130 
00132         void* GetUserData() const;
00133 
00135         void SetUserData(void* data);
00136 
00138         bool IsActive() const;
00139 
00143         bool GetCollideConnected() const;
00144 
00146         virtual void Dump() { b2Log("// Dump is not supported for this joint type.\n"); }
00147 
00148 protected:
00149         friend class b2World;
00150         friend class b2Body;
00151         friend class b2Island;
00152         friend class b2GearJoint;
00153 
00154         static b2Joint* Create(const b2JointDef* def, b2BlockAllocator* allocator);
00155         static void Destroy(b2Joint* joint, b2BlockAllocator* allocator);
00156 
00157         b2Joint(const b2JointDef* def);
00158         virtual ~b2Joint() {}
00159 
00160         virtual void InitVelocityConstraints(const b2SolverData& data) = 0;
00161         virtual void SolveVelocityConstraints(const b2SolverData& data) = 0;
00162 
00163         // This returns true if the position errors are within tolerance.
00164         virtual bool SolvePositionConstraints(const b2SolverData& data) = 0;
00165 
00166         b2JointType m_type;
00167         b2Joint* m_prev;
00168         b2Joint* m_next;
00169         b2JointEdge m_edgeA;
00170         b2JointEdge m_edgeB;
00171         b2Body* m_bodyA;
00172         b2Body* m_bodyB;
00173 
00174         int32 m_index;
00175 
00176         bool m_islandFlag;
00177         bool m_collideConnected;
00178 
00179         void* m_userData;
00180 };
00181 
00182 inline b2JointType b2Joint::GetType() const
00183 {
00184         return m_type;
00185 }
00186 
00187 inline b2Body* b2Joint::GetBodyA()
00188 {
00189         return m_bodyA;
00190 }
00191 
00192 inline b2Body* b2Joint::GetBodyB()
00193 {
00194         return m_bodyB;
00195 }
00196 
00197 inline b2Joint* b2Joint::GetNext()
00198 {
00199         return m_next;
00200 }
00201 
00202 inline const b2Joint* b2Joint::GetNext() const
00203 {
00204         return m_next;
00205 }
00206 
00207 inline void* b2Joint::GetUserData() const
00208 {
00209         return m_userData;
00210 }
00211 
00212 inline void b2Joint::SetUserData(void* data)
00213 {
00214         m_userData = data;
00215 }
00216 
00217 inline bool b2Joint::GetCollideConnected() const
00218 {
00219         return m_collideConnected;
00220 }
00221 
00222 #endif
 All Classes Files Functions Variables Enumerations Enumerator Defines