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1 /*
2 * Copyright (c) 2006-2007 Erin Catto
3 *
4 * This software is provided 'as-is', without any express or implied
5 * warranty. In no event will the authors be held liable for any damages
6 * arising from the use of this software.
7 * Permission is granted to anyone to use this software for any purpose,
8 * including commercial applications, and to alter it and redistribute it
9 * freely, subject to the following restrictions:
10 * 1. The origin of this software must not be misrepresented; you must not
11 * claim that you wrote the original software. If you use this software
12 * in a product, an acknowledgment in the product documentation would be
13 * appreciated but is not required.
14 * 2. Altered source versions must be plainly marked as such, and must not be
15 * misrepresented as being the original software.
16 * 3. This notice may not be removed or altered from any source distribution.
17 */
19 #ifndef B2_FRICTION_JOINT_H
20 #define B2_FRICTION_JOINT_H
22 #include <Box2D/Dynamics/Joints/b2Joint.h>
26 {
28  {
29  type = e_frictionJoint;
32  maxForce = 0.0f;
33  maxTorque = 0.0f;
34  }
38  void Initialize(b2Body* bodyA, b2Body* bodyB, const b2Vec2& anchor);
47  float32 maxForce;
50  float32 maxTorque;
51 };
55 class b2FrictionJoint : public b2Joint
56 {
57 public:
58  b2Vec2 GetAnchorA() const;
59  b2Vec2 GetAnchorB() const;
61  b2Vec2 GetReactionForce(float32 inv_dt) const;
62  float32 GetReactionTorque(float32 inv_dt) const;
65  const b2Vec2& GetLocalAnchorA() const { return m_localAnchorA; }
68  const b2Vec2& GetLocalAnchorB() const { return m_localAnchorB; }
71  void SetMaxForce(float32 force);
74  float32 GetMaxForce() const;
77  void SetMaxTorque(float32 torque);
80  float32 GetMaxTorque() const;
83  void Dump();
85 protected:
87  friend class b2Joint;
91  void InitVelocityConstraints(const b2SolverData& data);
92  void SolveVelocityConstraints(const b2SolverData& data);
93  bool SolvePositionConstraints(const b2SolverData& data);
95  b2Vec2 m_localAnchorA;
96  b2Vec2 m_localAnchorB;
98  // Solver shared
99  b2Vec2 m_linearImpulse;
100  float32 m_angularImpulse;
101  float32 m_maxForce;
102  float32 m_maxTorque;
104  // Solver temp
105  int32 m_indexA;
106  int32 m_indexB;
107  b2Vec2 m_rA;
108  b2Vec2 m_rB;
109  b2Vec2 m_localCenterA;
110  b2Vec2 m_localCenterB;
111  float32 m_invMassA;
112  float32 m_invMassB;
113  float32 m_invIA;
114  float32 m_invIB;
115  b2Mat22 m_linearMass;
116  float32 m_angularMass;
117 };
119 #endif
float32 maxTorque
The maximum friction torque in N-m.
Definition: b2FrictionJoint.h:50
b2Body * bodyA
The first attached body.
Definition: b2Joint.h:92
const b2Vec2 & GetLocalAnchorB() const
The local anchor point relative to bodyB's origin.
Definition: b2FrictionJoint.h:68
b2Vec2 localAnchorB
The local anchor point relative to bodyB's origin.
Definition: b2FrictionJoint.h:44
b2Body * bodyB
The second attached body.
Definition: b2Joint.h:95
float32 maxForce
The maximum friction force in N.
Definition: b2FrictionJoint.h:47
void SetMaxTorque(float32 torque)
Set the maximum friction torque in N*m.
Definition: b2FrictionJoint.cpp:226
Definition: b2Joint.h:103
float32 GetMaxTorque() const
Get the maximum friction torque in N*m.
Definition: b2FrictionJoint.cpp:232
float32 GetReactionTorque(float32 inv_dt) const
Get the reaction torque on bodyB in N*m.
Definition: b2FrictionJoint.cpp:210
void SetZero()
Set this vector to all zeros.
Definition: b2Math.h:65
const b2Vec2 & GetLocalAnchorA() const
The local anchor point relative to bodyA's origin.
Definition: b2FrictionJoint.h:65
Definition: b2FrictionJoint.h:55
b2JointType type
The joint type is set automatically for concrete joint types.
Definition: b2Joint.h:86
Solver Data.
Definition: b2TimeStep.h:65
float32 GetMaxForce() const
Get the maximum friction force in N.
Definition: b2FrictionJoint.cpp:221
b2Vec2 GetAnchorB() const
Get the anchor point on bodyB in world coordinates.
Definition: b2FrictionJoint.cpp:200
A 2-by-2 matrix. Stored in column-major order.
Definition: b2Math.h:244
b2Vec2 localAnchorA
The local anchor point relative to bodyA's origin.
Definition: b2FrictionJoint.h:41
Joint definitions are used to construct joints.
Definition: b2Joint.h:74
b2Vec2 GetAnchorA() const
Get the anchor point on bodyA in world coordinates.
Definition: b2FrictionJoint.cpp:195
A rigid body. These are created via b2World::CreateBody.
Definition: b2Body.h:132
void Dump()
Dump joint to dmLog.
Definition: b2FrictionJoint.cpp:237
A 2D column vector.
Definition: b2Math.h:56
Friction joint definition.
Definition: b2FrictionJoint.h:25
b2Vec2 GetReactionForce(float32 inv_dt) const
Get the reaction force on bodyB at the joint anchor in Newtons.
Definition: b2FrictionJoint.cpp:205
void Initialize(b2Body *bodyA, b2Body *bodyB, const b2Vec2 &anchor)
Definition: b2FrictionJoint.cpp:35
void SetMaxForce(float32 force)
Set the maximum friction force in N.
Definition: b2FrictionJoint.cpp:215