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b2PrismaticJoint.h

    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_PRISMATIC_JOINT_H
    00020 #define B2_PRISMATIC_JOINT_H
    00021
    00022 #include <Box2D/Dynamics/Joints/b2Joint.h>
    00023
    00030 struct b2PrismaticJointDef : public b2JointDef
    00031 {
    00032         b2PrismaticJointDef()
    00033         {
    00034                 type = e_prismaticJoint;
    00035                 localAnchorA.SetZero();
    00036                 localAnchorB.SetZero();
    00037                 localAxisA.Set(1.0f, 0.0f);
    00038                 referenceAngle = 0.0f;
    00039                 enableLimit = false;
    00040                 lowerTranslation = 0.0f;
    00041                 upperTranslation = 0.0f;
    00042                 enableMotor = false;
    00043                 maxMotorForce = 0.0f;
    00044                 motorSpeed = 0.0f;
    00045         }
    00046
    00049         void Initialize(b2Body* bodyA, b2Body* bodyB, const b2Vec2& anchor, const b2Vec2& axis);
    00050
    00052         b2Vec2 localAnchorA;
    00053
    00055         b2Vec2 localAnchorB;
    00056
    00058         b2Vec2 localAxisA;
    00059
    00061         float32 referenceAngle;
    00062
    00064         bool enableLimit;
    00065
    00067         float32 lowerTranslation;
    00068
    00070         float32 upperTranslation;
    00071
    00073         bool enableMotor;
    00074
    00076         float32 maxMotorForce;
    00077
    00079         float32 motorSpeed;
    00080 };
    00081
    00086 class b2PrismaticJoint : public b2Joint
    00087 {
    00088 public:
    00089         b2Vec2 GetAnchorA() const;
    00090         b2Vec2 GetAnchorB() const;
    00091
    00092         b2Vec2 GetReactionForce(float32 inv_dt) const;
    00093         float32 GetReactionTorque(float32 inv_dt) const;
    00094
    00096         const b2Vec2& GetLocalAnchorA() const { return m_localAnchorA; }
    00097
    00099         const b2Vec2& GetLocalAnchorB() const  { return m_localAnchorB; }
    00100
    00102         const b2Vec2& GetLocalAxisA() const { return m_localXAxisA; }
    00103
    00105         float32 GetReferenceAngle() const { return m_referenceAngle; }
    00106
    00108         float32 GetJointTranslation() const;
    00109
    00111         float32 GetJointSpeed() const;
    00112
    00114         bool IsLimitEnabled() const;
    00115
    00117         void EnableLimit(bool flag);
    00118
    00120         float32 GetLowerLimit() const;
    00121
    00123         float32 GetUpperLimit() const;
    00124
    00126         void SetLimits(float32 lower, float32 upper);
    00127
    00129         bool IsMotorEnabled() const;
    00130
    00132         void EnableMotor(bool flag);
    00133
    00135         void SetMotorSpeed(float32 speed);
    00136
    00138         float32 GetMotorSpeed() const;
    00139
    00141         void SetMaxMotorForce(float32 force);
    00142         float32 GetMaxMotorForce() const { return m_maxMotorForce; }
    00143
    00145         float32 GetMotorForce(float32 inv_dt) const;
    00146
    00148         void Dump();
    00149
    00150 protected:
    00151         friend class b2Joint;
    00152         friend class b2GearJoint;
    00153         b2PrismaticJoint(const b2PrismaticJointDef* def);
    00154
    00155         void InitVelocityConstraints(const b2SolverData& data);
    00156         void SolveVelocityConstraints(const b2SolverData& data);
    00157         bool SolvePositionConstraints(const b2SolverData& data);
    00158
    00159         // Solver shared
    00160         b2Vec2 m_localAnchorA;
    00161         b2Vec2 m_localAnchorB;
    00162         b2Vec2 m_localXAxisA;
    00163         b2Vec2 m_localYAxisA;
    00164         float32 m_referenceAngle;
    00165         b2Vec3 m_impulse;
    00166         float32 m_motorImpulse;
    00167         float32 m_lowerTranslation;
    00168         float32 m_upperTranslation;
    00169         float32 m_maxMotorForce;
    00170         float32 m_motorSpeed;
    00171         bool m_enableLimit;
    00172         bool m_enableMotor;
    00173         b2LimitState m_limitState;
    00174
    00175         // Solver temp
    00176         int32 m_indexA;
    00177         int32 m_indexB;
    00178         b2Vec2 m_localCenterA;
    00179         b2Vec2 m_localCenterB;
    00180         float32 m_invMassA;
    00181         float32 m_invMassB;
    00182         float32 m_invIA;
    00183         float32 m_invIB;
    00184         b2Vec2 m_axis, m_perp;
    00185         float32 m_s1, m_s2;
    00186         float32 m_a1, m_a2;
    00187         b2Mat33 m_K;
    00188         float32 m_motorMass;
    00189 };
    00190
    00191 inline float32 b2PrismaticJoint::GetMotorSpeed() const
    00192 {
    00193         return m_motorSpeed;
    00194 }
    00195
    00196 #endif

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