![]() |
Box2D
2.2.1
A 2D Physics Engine for Games
|
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_PULLEY_JOINT_H 00020 #define B2_PULLEY_JOINT_H 00021 00022 #include <Box2D/Dynamics/Joints/b2Joint.h> 00023 00024 const float32 b2_minPulleyLength = 2.0f; 00025 00028 struct b2PulleyJointDef : public b2JointDef 00029 { 00030 b2PulleyJointDef() 00031 { 00032 type = e_pulleyJoint; 00033 groundAnchorA.Set(-1.0f, 1.0f); 00034 groundAnchorB.Set(1.0f, 1.0f); 00035 localAnchorA.Set(-1.0f, 0.0f); 00036 localAnchorB.Set(1.0f, 0.0f); 00037 lengthA = 0.0f; 00038 lengthB = 0.0f; 00039 ratio = 1.0f; 00040 collideConnected = true; 00041 } 00042 00044 void Initialize(b2Body* bodyA, b2Body* bodyB, 00045 const b2Vec2& groundAnchorA, const b2Vec2& groundAnchorB, 00046 const b2Vec2& anchorA, const b2Vec2& anchorB, 00047 float32 ratio); 00048 00050 b2Vec2 groundAnchorA; 00051 00053 b2Vec2 groundAnchorB; 00054 00056 b2Vec2 localAnchorA; 00057 00059 b2Vec2 localAnchorB; 00060 00062 float32 lengthA; 00063 00065 float32 lengthB; 00066 00068 float32 ratio; 00069 }; 00070 00079 class b2PulleyJoint : public b2Joint 00080 { 00081 public: 00082 b2Vec2 GetAnchorA() const; 00083 b2Vec2 GetAnchorB() const; 00084 00085 b2Vec2 GetReactionForce(float32 inv_dt) const; 00086 float32 GetReactionTorque(float32 inv_dt) const; 00087 00089 b2Vec2 GetGroundAnchorA() const; 00090 00092 b2Vec2 GetGroundAnchorB() const; 00093 00095 float32 GetLengthA() const; 00096 00098 float32 GetLengthB() const; 00099 00101 float32 GetRatio() const; 00102 00104 void Dump(); 00105 00106 protected: 00107 00108 friend class b2Joint; 00109 b2PulleyJoint(const b2PulleyJointDef* data); 00110 00111 void InitVelocityConstraints(const b2SolverData& data); 00112 void SolveVelocityConstraints(const b2SolverData& data); 00113 bool SolvePositionConstraints(const b2SolverData& data); 00114 00115 b2Vec2 m_groundAnchorA; 00116 b2Vec2 m_groundAnchorB; 00117 float32 m_lengthA; 00118 float32 m_lengthB; 00119 00120 // Solver shared 00121 b2Vec2 m_localAnchorA; 00122 b2Vec2 m_localAnchorB; 00123 float32 m_constant; 00124 float32 m_ratio; 00125 float32 m_impulse; 00126 00127 // Solver temp 00128 int32 m_indexA; 00129 int32 m_indexB; 00130 b2Vec2 m_uA; 00131 b2Vec2 m_uB; 00132 b2Vec2 m_rA; 00133 b2Vec2 m_rB; 00134 b2Vec2 m_localCenterA; 00135 b2Vec2 m_localCenterB; 00136 float32 m_invMassA; 00137 float32 m_invMassB; 00138 float32 m_invIA; 00139 float32 m_invIB; 00140 float32 m_mass; 00141 }; 00142 00143 #endif