Box2D 2.3.0 A 2D Physics Engine for Games

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b2FrictionJoint.h
1 /*
2 * Copyright (c) 2006-2007 Erin Catto http://www.box2d.org
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 */
18
19 #ifndef B2_FRICTION_JOINT_H
20 #define B2_FRICTION_JOINT_H
21
22 #include <Box2D/Dynamics/Joints/b2Joint.h>
23
25 struct b2FrictionJointDef : public b2JointDef
26 {
27 b2FrictionJointDef()
28 {
29 type = e_frictionJoint;
30 localAnchorA.SetZero();
31 localAnchorB.SetZero();
32 maxForce = 0.0f;
33 maxTorque = 0.0f;
34 }
35
38 void Initialize(b2Body* bodyA, b2Body* bodyB, const b2Vec2& anchor);
39
41 b2Vec2 localAnchorA;
42
44 b2Vec2 localAnchorB;
45
47 float32 maxForce;
48
50 float32 maxTorque;
51 };
52
55 class b2FrictionJoint : public b2Joint
56 {
57 public:
58 b2Vec2 GetAnchorA() const;
59 b2Vec2 GetAnchorB() const;
60
61 b2Vec2 GetReactionForce(float32 inv_dt) const;
62 float32 GetReactionTorque(float32 inv_dt) const;
63
65 const b2Vec2& GetLocalAnchorA() const { return m_localAnchorA; }
66
68 const b2Vec2& GetLocalAnchorB() const { return m_localAnchorB; }
69
71 void SetMaxForce(float32 force);
72
74 float32 GetMaxForce() const;
75
77 void SetMaxTorque(float32 torque);
78
80 float32 GetMaxTorque() const;
81
83 void Dump();
84
85 protected:
86
87 friend class b2Joint;
88
89 b2FrictionJoint(const b2FrictionJointDef* def);
90
91 void InitVelocityConstraints(const b2SolverData& data);
92 void SolveVelocityConstraints(const b2SolverData& data);
93 bool SolvePositionConstraints(const b2SolverData& data);
94
95 b2Vec2 m_localAnchorA;
96 b2Vec2 m_localAnchorB;
97
98 // Solver shared
99 b2Vec2 m_linearImpulse;
100 float32 m_angularImpulse;
101 float32 m_maxForce;
102 float32 m_maxTorque;
103
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 };
118
119 #endif
b2FrictionJointDef::maxTorque
float32 maxTorque
The maximum friction torque in N-m.
Definition: b2FrictionJoint.h:50
b2JointDef::bodyA
b2Body * bodyA
The first attached body.
Definition: b2Joint.h:92
b2FrictionJoint::GetLocalAnchorB
const b2Vec2 & GetLocalAnchorB() const
The local anchor point relative to bodyB's origin.
Definition: b2FrictionJoint.h:68
b2FrictionJointDef::localAnchorB
b2Vec2 localAnchorB
The local anchor point relative to bodyB's origin.
Definition: b2FrictionJoint.h:44
b2JointDef::bodyB
b2Body * bodyB
The second attached body.
Definition: b2Joint.h:95
b2FrictionJointDef::maxForce
float32 maxForce
The maximum friction force in N.
Definition: b2FrictionJoint.h:47
b2FrictionJoint::SetMaxTorque
void SetMaxTorque(float32 torque)
Set the maximum friction torque in N*m.
Definition: b2FrictionJoint.cpp:226
b2Joint
Definition: b2Joint.h:103
b2FrictionJoint::GetMaxTorque
float32 GetMaxTorque() const
Get the maximum friction torque in N*m.
Definition: b2FrictionJoint.cpp:232
b2FrictionJoint::GetReactionTorque
float32 GetReactionTorque(float32 inv_dt) const
Get the reaction torque on bodyB in N*m.
Definition: b2FrictionJoint.cpp:210
b2Vec2::SetZero
void SetZero()
Set this vector to all zeros.
Definition: b2Math.h:62
b2FrictionJoint::GetLocalAnchorA
const b2Vec2 & GetLocalAnchorA() const
The local anchor point relative to bodyA's origin.
Definition: b2FrictionJoint.h:65
b2FrictionJoint
Definition: b2FrictionJoint.h:55
b2JointDef::type
b2JointType type
The joint type is set automatically for concrete joint types.
Definition: b2Joint.h:86
b2SolverData
Solver Data.
Definition: b2TimeStep.h:63
b2FrictionJoint::GetMaxForce
float32 GetMaxForce() const
Get the maximum friction force in N.
Definition: b2FrictionJoint.cpp:221
b2FrictionJoint::GetAnchorB
b2Vec2 GetAnchorB() const
Get the anchor point on bodyB in world coordinates.
Definition: b2FrictionJoint.cpp:200
b2Mat22
A 2-by-2 matrix. Stored in column-major order.
Definition: b2Math.h:183
b2FrictionJointDef::localAnchorA
b2Vec2 localAnchorA
The local anchor point relative to bodyA's origin.
Definition: b2FrictionJoint.h:41
b2JointDef
Joint definitions are used to construct joints.
Definition: b2Joint.h:74
b2FrictionJoint::GetAnchorA
b2Vec2 GetAnchorA() const
Get the anchor point on bodyA in world coordinates.
Definition: b2FrictionJoint.cpp:195
b2Body
A rigid body. These are created via b2World::CreateBody.
Definition: b2Body.h:126
b2FrictionJoint::Dump
void Dump()
Dump joint to dmLog.
Definition: b2FrictionJoint.cpp:237
b2Vec2
A 2D column vector.
Definition: b2Math.h:53
b2FrictionJointDef
Friction joint definition.
Definition: b2FrictionJoint.h:25
b2FrictionJoint::GetReactionForce
b2Vec2 GetReactionForce(float32 inv_dt) const
Get the reaction force on bodyB at the joint anchor in Newtons.
Definition: b2FrictionJoint.cpp:205
b2FrictionJointDef::Initialize
void Initialize(b2Body *bodyA, b2Body *bodyB, const b2Vec2 &anchor)
Definition: b2FrictionJoint.cpp:35
b2FrictionJoint::SetMaxForce
void SetMaxForce(float32 force)
Set the maximum friction force in N.
Definition: b2FrictionJoint.cpp:215