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Box2D
2.2.0
A 2D Physics Engine for Games
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00001 /* 00002 * Copyright (c) 2006-2011 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_ROPE_JOINT_H 00020 #define B2_ROPE_JOINT_H 00021 00022 #include <Box2D/Dynamics/Joints/b2Joint.h> 00023 00028 struct b2RopeJointDef : public b2JointDef 00029 { 00030 b2RopeJointDef() 00031 { 00032 type = e_ropeJoint; 00033 localAnchorA.Set(-1.0f, 0.0f); 00034 localAnchorB.Set(1.0f, 0.0f); 00035 maxLength = 0.0f; 00036 } 00037 00039 b2Vec2 localAnchorA; 00040 00042 b2Vec2 localAnchorB; 00043 00047 float32 maxLength; 00048 }; 00049 00058 class b2RopeJoint : public b2Joint 00059 { 00060 public: 00061 b2Vec2 GetAnchorA() const; 00062 b2Vec2 GetAnchorB() const; 00063 00064 b2Vec2 GetReactionForce(float32 inv_dt) const; 00065 float32 GetReactionTorque(float32 inv_dt) const; 00066 00068 float32 GetMaxLength() const; 00069 00070 b2LimitState GetLimitState() const; 00071 00072 protected: 00073 00074 friend class b2Joint; 00075 b2RopeJoint(const b2RopeJointDef* data); 00076 00077 void InitVelocityConstraints(const b2SolverData& data); 00078 void SolveVelocityConstraints(const b2SolverData& data); 00079 bool SolvePositionConstraints(const b2SolverData& data); 00080 00081 // Solver shared 00082 b2Vec2 m_localAnchorA; 00083 b2Vec2 m_localAnchorB; 00084 float32 m_maxLength; 00085 float32 m_length; 00086 float32 m_impulse; 00087 00088 // Solver temp 00089 int32 m_indexA; 00090 int32 m_indexB; 00091 b2Vec2 m_u; 00092 b2Vec2 m_rA; 00093 b2Vec2 m_rB; 00094 b2Vec2 m_localCenterA; 00095 b2Vec2 m_localCenterB; 00096 float32 m_invMassA; 00097 float32 m_invMassB; 00098 float32 m_invIA; 00099 float32 m_invIB; 00100 float32 m_mass; 00101 b2LimitState m_state; 00102 }; 00103 00104 #endif