Box2D 2.3.0 A 2D Physics Engine for Games

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b2GearJoint.h
1 /*
2 * Copyright (c) 2006-2011 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_GEAR_JOINT_H
20 #define B2_GEAR_JOINT_H
21
22 #include <Box2D/Dynamics/Joints/b2Joint.h>
23
26 struct b2GearJointDef : public b2JointDef
27 {
28 b2GearJointDef()
29 {
30 type = e_gearJoint;
31 joint1 = NULL;
32 joint2 = NULL;
33 ratio = 1.0f;
34 }
35
37 b2Joint* joint1;
38
40 b2Joint* joint2;
41
44 float32 ratio;
45 };
46
56 class b2GearJoint : public b2Joint
57 {
58 public:
59 b2Vec2 GetAnchorA() const;
60 b2Vec2 GetAnchorB() const;
61
62 b2Vec2 GetReactionForce(float32 inv_dt) const;
63 float32 GetReactionTorque(float32 inv_dt) const;
64
66 b2Joint* GetJoint1() { return m_joint1; }
67
69 b2Joint* GetJoint2() { return m_joint2; }
70
72 void SetRatio(float32 ratio);
73 float32 GetRatio() const;
74
76 void Dump();
77
78 protected:
79
80 friend class b2Joint;
81 b2GearJoint(const b2GearJointDef* data);
82
83 void InitVelocityConstraints(const b2SolverData& data);
84 void SolveVelocityConstraints(const b2SolverData& data);
85 bool SolvePositionConstraints(const b2SolverData& data);
86
87 b2Joint* m_joint1;
88 b2Joint* m_joint2;
89
90 b2JointType m_typeA;
91 b2JointType m_typeB;
92
93 // Body A is connected to body C
94 // Body B is connected to body D
95 b2Body* m_bodyC;
96 b2Body* m_bodyD;
97
98 // Solver shared
99 b2Vec2 m_localAnchorA;
100 b2Vec2 m_localAnchorB;
101 b2Vec2 m_localAnchorC;
102 b2Vec2 m_localAnchorD;
103
104 b2Vec2 m_localAxisC;
105 b2Vec2 m_localAxisD;
106
107 float32 m_referenceAngleA;
108 float32 m_referenceAngleB;
109
110 float32 m_constant;
111 float32 m_ratio;
112
113 float32 m_impulse;
114
115 // Solver temp
116 int32 m_indexA, m_indexB, m_indexC, m_indexD;
117 b2Vec2 m_lcA, m_lcB, m_lcC, m_lcD;
118 float32 m_mA, m_mB, m_mC, m_mD;
119 float32 m_iA, m_iB, m_iC, m_iD;
120 b2Vec2 m_JvAC, m_JvBD;
121 float32 m_JwA, m_JwB, m_JwC, m_JwD;
122 float32 m_mass;
123 };
124
125 #endif
b2GearJoint::SetRatio
void SetRatio(float32 ratio)
Set/Get the gear ratio.
Definition: b2GearJoint.cpp:392
b2GearJointDef::joint1
b2Joint * joint1
The first revolute/prismatic joint attached to the gear joint.
Definition: b2GearJoint.h:37
b2GearJoint::GetAnchorB
b2Vec2 GetAnchorB() const
Get the anchor point on bodyB in world coordinates.
Definition: b2GearJoint.cpp:375
b2Joint
Definition: b2Joint.h:103
b2GearJoint::GetAnchorA
b2Vec2 GetAnchorA() const
Get the anchor point on bodyA in world coordinates.
Definition: b2GearJoint.cpp:370
b2GearJoint::GetReactionForce
b2Vec2 GetReactionForce(float32 inv_dt) const
Get the reaction force on bodyB at the joint anchor in Newtons.
Definition: b2GearJoint.cpp:380
b2GearJoint
Definition: b2GearJoint.h:56
b2GearJointDef::joint2
b2Joint * joint2
The second revolute/prismatic joint attached to the gear joint.
Definition: b2GearJoint.h:40
b2GearJointDef::ratio
float32 ratio
Definition: b2GearJoint.h:44
b2GearJoint::GetJoint1
b2Joint * GetJoint1()
Get the first joint.
Definition: b2GearJoint.h:66
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
b2JointDef
Joint definitions are used to construct joints.
Definition: b2Joint.h:74
b2GearJoint::GetReactionTorque
float32 GetReactionTorque(float32 inv_dt) const
Get the reaction torque on bodyB in N*m.
Definition: b2GearJoint.cpp:386
b2Body
A rigid body. These are created via b2World::CreateBody.
Definition: b2Body.h:126
b2GearJoint::Dump
void Dump()
Dump joint to dmLog.
Definition: b2GearJoint.cpp:403
b2Vec2
A 2D column vector.
Definition: b2Math.h:53
b2GearJointDef
Definition: b2GearJoint.h:26
b2GearJoint::GetJoint2
b2Joint * GetJoint2()
Get the second joint.
Definition: b2GearJoint.h:69