00001 /* 00002 * Copyright (c) 2006-2009 Erin Catto http://www.gphysics.com 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_WELD_JOINT_H 00020 #define B2_WELD_JOINT_H 00021 00022 #include <Box2D/Dynamics/Joints/b2Joint.h> 00023 00027 struct b2WeldJointDef : public b2JointDef 00028 { 00029 b2WeldJointDef() 00030 { 00031 type = e_weldJoint; 00032 localAnchorA.Set(0.0f, 0.0f); 00033 localAnchorB.Set(0.0f, 0.0f); 00034 referenceAngle = 0.0f; 00035 } 00036 00039 void Initialize(b2Body* body1, b2Body* body2, const b2Vec2& anchor); 00040 00042 b2Vec2 localAnchorA; 00043 00045 b2Vec2 localAnchorB; 00046 00048 float32 referenceAngle; 00049 }; 00050 00053 class b2WeldJoint : public b2Joint 00054 { 00055 public: 00056 b2Vec2 GetAnchorA() const; 00057 b2Vec2 GetAnchorB() const; 00058 00059 b2Vec2 GetReactionForce(float32 inv_dt) const; 00060 float32 GetReactionTorque(float32 inv_dt) const; 00061 00062 protected: 00063 00064 friend class b2Joint; 00065 00066 b2WeldJoint(const b2WeldJointDef* def); 00067 00068 void InitVelocityConstraints(const b2TimeStep& step); 00069 void SolveVelocityConstraints(const b2TimeStep& step); 00070 00071 bool SolvePositionConstraints(float32 baumgarte); 00072 00073 b2Vec2 m_localAnchorA; 00074 b2Vec2 m_localAnchorB; 00075 float32 m_referenceAngle; 00076 00077 b2Vec3 m_impulse; 00078 00079 b2Mat33 m_mass; 00080 }; 00081 00082 #endif