1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
|
/*
* Copyright (c) 2006-2012 Erin Catto http://www.box2d.org
*
* This software is provided 'as-is', without any express or implied
* warranty. In no event will the authors be held liable for any damages
* arising from the use of this software.
* Permission is granted to anyone to use this software for any purpose,
* including commercial applications, and to alter it and redistribute it
* freely, subject to the following restrictions:
* 1. The origin of this software must not be misrepresented; you must not
* claim that you wrote the original software. If you use this software
* in a product, an acknowledgment in the product documentation would be
* appreciated but is not required.
* 2. Altered source versions must be plainly marked as such, and must not be
* misrepresented as being the original software.
* 3. This notice may not be removed or altered from any source distribution.
*/
#ifndef B2_MOTOR_JOINT_H
#define B2_MOTOR_JOINT_H
#include "Box2D/Dynamics/Joints/b2Joint.h"
/// Motor joint definition.
struct b2MotorJointDef : public b2JointDef
{
b2MotorJointDef()
{
type = e_motorJoint;
linearOffset.SetZero();
angularOffset = 0.0f;
maxForce = 1.0f;
maxTorque = 1.0f;
correctionFactor = 0.3f;
}
/// Initialize the bodies and offsets using the current transforms.
void Initialize(b2Body* bodyA, b2Body* bodyB);
/// Position of bodyB minus the position of bodyA, in bodyA's frame, in meters.
b2Vec2 linearOffset;
/// The bodyB angle minus bodyA angle in radians.
float32 angularOffset;
/// The maximum motor force in N.
float32 maxForce;
/// The maximum motor torque in N-m.
float32 maxTorque;
/// Position correction factor in the range [0,1].
float32 correctionFactor;
};
/// A motor joint is used to control the relative motion
/// between two bodies. A typical usage is to control the movement
/// of a dynamic body with respect to the ground.
class b2MotorJoint : public b2Joint
{
public:
b2Vec2 GetAnchorA() const override;
b2Vec2 GetAnchorB() const override;
b2Vec2 GetReactionForce(float32 inv_dt) const override;
float32 GetReactionTorque(float32 inv_dt) const override;
/// Set/get the target linear offset, in frame A, in meters.
void SetLinearOffset(const b2Vec2& linearOffset);
const b2Vec2& GetLinearOffset() const;
/// Set/get the target angular offset, in radians.
void SetAngularOffset(float32 angularOffset);
float32 GetAngularOffset() const;
/// Set the maximum friction force in N.
void SetMaxForce(float32 force);
/// Get the maximum friction force in N.
float32 GetMaxForce() const;
/// Set the maximum friction torque in N*m.
void SetMaxTorque(float32 torque);
/// Get the maximum friction torque in N*m.
float32 GetMaxTorque() const;
/// Set the position correction factor in the range [0,1].
void SetCorrectionFactor(float32 factor);
/// Get the position correction factor in the range [0,1].
float32 GetCorrectionFactor() const;
/// Dump to b2Log
void Dump() override;
protected:
friend class b2Joint;
b2MotorJoint(const b2MotorJointDef* def);
void InitVelocityConstraints(const b2SolverData& data) override;
void SolveVelocityConstraints(const b2SolverData& data) override;
bool SolvePositionConstraints(const b2SolverData& data) override;
// Solver shared
b2Vec2 m_linearOffset;
float32 m_angularOffset;
b2Vec2 m_linearImpulse;
float32 m_angularImpulse;
float32 m_maxForce;
float32 m_maxTorque;
float32 m_correctionFactor;
// Solver temp
int32 m_indexA;
int32 m_indexB;
b2Vec2 m_rA;
b2Vec2 m_rB;
b2Vec2 m_localCenterA;
b2Vec2 m_localCenterB;
b2Vec2 m_linearError;
float32 m_angularError;
float32 m_invMassA;
float32 m_invMassB;
float32 m_invIA;
float32 m_invIB;
b2Mat22 m_linearMass;
float32 m_angularMass;
};
#endif
|
