00001 /* 00002 * Copyright (c) 2006-2007 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_MOUSE_JOINT_H 00020 #define B2_MOUSE_JOINT_H 00021 00022 #include <Box2D/Dynamics/Joints/b2Joint.h> 00023 00026 struct b2MouseJointDef : public b2JointDef 00027 { 00028 b2MouseJointDef() 00029 { 00030 type = e_mouseJoint; 00031 target.Set(0.0f, 0.0f); 00032 maxForce = 0.0f; 00033 frequencyHz = 5.0f; 00034 dampingRatio = 0.7f; 00035 } 00036 00039 b2Vec2 target; 00040 00044 float32 maxForce; 00045 00047 float32 frequencyHz; 00048 00050 float32 dampingRatio; 00051 }; 00052 00060 class b2MouseJoint : public b2Joint 00061 { 00062 public: 00063 00065 b2Vec2 GetAnchorA() const; 00066 00068 b2Vec2 GetAnchorB() const; 00069 00071 b2Vec2 GetReactionForce(float32 inv_dt) const; 00072 00074 float32 GetReactionTorque(float32 inv_dt) const; 00075 00077 void SetTarget(const b2Vec2& target); 00078 const b2Vec2& GetTarget() const; 00079 00081 void SetMaxForce(float32 force); 00082 float32 GetMaxForce() const; 00083 00085 void SetFrequency(float32 hz); 00086 float32 GetFrequency() const; 00087 00089 void SetDampingRatio(float32 ratio); 00090 float32 GetDampingRatio() const; 00091 00092 protected: 00093 friend class b2Joint; 00094 00095 b2MouseJoint(const b2MouseJointDef* def); 00096 00097 void InitVelocityConstraints(const b2TimeStep& step); 00098 void SolveVelocityConstraints(const b2TimeStep& step); 00099 bool SolvePositionConstraints(float32 baumgarte) { B2_NOT_USED(baumgarte); return true; } 00100 00101 b2Vec2 m_localAnchor; 00102 b2Vec2 m_target; 00103 b2Vec2 m_impulse; 00104 00105 b2Mat22 m_mass; // effective mass for point-to-point constraint. 00106 b2Vec2 m_C; // position error 00107 float32 m_maxForce; 00108 float32 m_frequencyHz; 00109 float32 m_dampingRatio; 00110 float32 m_beta; 00111 float32 m_gamma; 00112 }; 00113 00114 #endif