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b2DistanceJoint.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_DISTANCE_JOINT_H
    00020 #define B2_DISTANCE_JOINT_H
    00021
    00022 #include <Box2D/Dynamics/Joints/b2Joint.h>
    00023
    00030 struct b2DistanceJointDef : public b2JointDef
    00031 {
    00032         b2DistanceJointDef()
    00033         {
    00034                 type = e_distanceJoint;
    00035                 localAnchorA.Set(0.0f, 0.0f);
    00036                 localAnchorB.Set(0.0f, 0.0f);
    00037                 length = 1.0f;
    00038                 frequencyHz = 0.0f;
    00039                 dampingRatio = 0.0f;
    00040         }
    00041
    00044         void Initialize(b2Body* bodyA, b2Body* bodyB,
    00045                                         const b2Vec2& anchorA, const b2Vec2& anchorB);
    00046
    00048         b2Vec2 localAnchorA;
    00049
    00051         b2Vec2 localAnchorB;
    00052
    00054         float32 length;
    00055
    00058         float32 frequencyHz;
    00059
    00061         float32 dampingRatio;
    00062 };
    00063
    00067 class b2DistanceJoint : public b2Joint
    00068 {
    00069 public:
    00070
    00071         b2Vec2 GetAnchorA() const;
    00072         b2Vec2 GetAnchorB() const;
    00073
    00076         b2Vec2 GetReactionForce(float32 inv_dt) const;
    00077
    00080         float32 GetReactionTorque(float32 inv_dt) const;
    00081
    00083         const b2Vec2& GetLocalAnchorA() const { return m_localAnchorA; }
    00084
    00086         const b2Vec2& GetLocalAnchorB() const  { return m_localAnchorB; }
    00087
    00090         void SetLength(float32 length);
    00091         float32 GetLength() const;
    00092
    00094         void SetFrequency(float32 hz);
    00095         float32 GetFrequency() const;
    00096
    00098         void SetDampingRatio(float32 ratio);
    00099         float32 GetDampingRatio() const;
    00100
    00102         void Dump();
    00103
    00104 protected:
    00105
    00106         friend class b2Joint;
    00107         b2DistanceJoint(const b2DistanceJointDef* data);
    00108
    00109         void InitVelocityConstraints(const b2SolverData& data);
    00110         void SolveVelocityConstraints(const b2SolverData& data);
    00111         bool SolvePositionConstraints(const b2SolverData& data);
    00112
    00113         float32 m_frequencyHz;
    00114         float32 m_dampingRatio;
    00115         float32 m_bias;
    00116
    00117         // Solver shared
    00118         b2Vec2 m_localAnchorA;
    00119         b2Vec2 m_localAnchorB;
    00120         float32 m_gamma;
    00121         float32 m_impulse;
    00122         float32 m_length;
    00123
    00124         // Solver temp
    00125         int32 m_indexA;
    00126         int32 m_indexB;
    00127         b2Vec2 m_u;
    00128         b2Vec2 m_rA;
    00129         b2Vec2 m_rB;
    00130         b2Vec2 m_localCenterA;
    00131         b2Vec2 m_localCenterB;
    00132         float32 m_invMassA;
    00133         float32 m_invMassB;
    00134         float32 m_invIA;
    00135         float32 m_invIB;
    00136         float32 m_mass;
    00137 };
    00138
    00139 inline void b2DistanceJoint::SetLength(float32 length)
    00140 {
    00141         m_length = length;
    00142 }
    00143
    00144 inline float32 b2DistanceJoint::GetLength() const
    00145 {
    00146         return m_length;
    00147 }
    00148
    00149 inline void b2DistanceJoint::SetFrequency(float32 hz)
    00150 {
    00151         m_frequencyHz = hz;
    00152 }
    00153
    00154 inline float32 b2DistanceJoint::GetFrequency() const
    00155 {
    00156         return m_frequencyHz;
    00157 }
    00158
    00159 inline void b2DistanceJoint::SetDampingRatio(float32 ratio)
    00160 {
    00161         m_dampingRatio = ratio;
    00162 }
    00163
    00164 inline float32 b2DistanceJoint::GetDampingRatio() const
    00165 {
    00166         return m_dampingRatio;
    00167 }
    00168
    00169 #endif

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