Box2D 2.3.0 A 2D Physics Engine for Games

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b2WeldJoint.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_WELD_JOINT_H
20 #define B2_WELD_JOINT_H
21
22 #include <Box2D/Dynamics/Joints/b2Joint.h>
23
27 struct b2WeldJointDef : public b2JointDef
28 {
29 b2WeldJointDef()
30 {
31 type = e_weldJoint;
32 localAnchorA.Set(0.0f, 0.0f);
33 localAnchorB.Set(0.0f, 0.0f);
34 referenceAngle = 0.0f;
35 frequencyHz = 0.0f;
36 dampingRatio = 0.0f;
37 }
38
41 void Initialize(b2Body* bodyA, b2Body* bodyB, const b2Vec2& anchor);
42
44 b2Vec2 localAnchorA;
45
47 b2Vec2 localAnchorB;
48
50 float32 referenceAngle;
51
54 float32 frequencyHz;
55
57 float32 dampingRatio;
58 };
59
62 class b2WeldJoint : public b2Joint
63 {
64 public:
65 b2Vec2 GetAnchorA() const;
66 b2Vec2 GetAnchorB() const;
67
68 b2Vec2 GetReactionForce(float32 inv_dt) const;
69 float32 GetReactionTorque(float32 inv_dt) const;
70
72 const b2Vec2& GetLocalAnchorA() const { return m_localAnchorA; }
73
75 const b2Vec2& GetLocalAnchorB() const { return m_localAnchorB; }
76
78 float32 GetReferenceAngle() const { return m_referenceAngle; }
79
81 void SetFrequency(float32 hz) { m_frequencyHz = hz; }
82 float32 GetFrequency() const { return m_frequencyHz; }
83
85 void SetDampingRatio(float32 ratio) { m_dampingRatio = ratio; }
86 float32 GetDampingRatio() const { return m_dampingRatio; }
87
89 void Dump();
90
91 protected:
92
93 friend class b2Joint;
94
95 b2WeldJoint(const b2WeldJointDef* def);
96
97 void InitVelocityConstraints(const b2SolverData& data);
98 void SolveVelocityConstraints(const b2SolverData& data);
99 bool SolvePositionConstraints(const b2SolverData& data);
100
101 float32 m_frequencyHz;
102 float32 m_dampingRatio;
103 float32 m_bias;
104
105 // Solver shared
106 b2Vec2 m_localAnchorA;
107 b2Vec2 m_localAnchorB;
108 float32 m_referenceAngle;
109 float32 m_gamma;
110 b2Vec3 m_impulse;
111
112 // Solver temp
113 int32 m_indexA;
114 int32 m_indexB;
115 b2Vec2 m_rA;
116 b2Vec2 m_rB;
117 b2Vec2 m_localCenterA;
118 b2Vec2 m_localCenterB;
119 float32 m_invMassA;
120 float32 m_invMassB;
121 float32 m_invIA;
122 float32 m_invIB;
123 b2Mat33 m_mass;
124 };
125
126 #endif
b2Vec3
A 2D column vector with 3 elements.
Definition: b2Math.h:144
b2JointDef::bodyA
b2Body * bodyA
The first attached body.
Definition: b2Joint.h:92
b2WeldJointDef::localAnchorB
b2Vec2 localAnchorB
The local anchor point relative to bodyB's origin.
Definition: b2WeldJoint.h:47
b2Mat33
A 3-by-3 matrix. Stored in column-major order.
Definition: b2Math.h:257
b2WeldJoint::SetFrequency
void SetFrequency(float32 hz)
Set/get frequency in Hz.
Definition: b2WeldJoint.h:81
b2JointDef::bodyB
b2Body * bodyB
The second attached body.
Definition: b2Joint.h:95
b2Joint
Definition: b2Joint.h:103
b2WeldJoint::GetLocalAnchorB
const b2Vec2 & GetLocalAnchorB() const
The local anchor point relative to bodyB's origin.
Definition: b2WeldJoint.h:75
b2WeldJoint
Definition: b2WeldJoint.h:62
b2Vec2::Set
void Set(float32 x_, float32 y_)
Set this vector to some specified coordinates.
Definition: b2Math.h:65
b2WeldJoint::GetReactionForce
b2Vec2 GetReactionForce(float32 inv_dt) const
Get the reaction force on bodyB at the joint anchor in Newtons.
Definition: b2WeldJoint.cpp:318
b2WeldJoint::GetLocalAnchorA
const b2Vec2 & GetLocalAnchorA() const
The local anchor point relative to bodyA's origin.
Definition: b2WeldJoint.h:72
b2WeldJointDef
Definition: b2WeldJoint.h:27
b2WeldJoint::GetReactionTorque
float32 GetReactionTorque(float32 inv_dt) const
Get the reaction torque on bodyB in N*m.
Definition: b2WeldJoint.cpp:324
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
b2WeldJointDef::frequencyHz
float32 frequencyHz
Definition: b2WeldJoint.h:54
b2JointDef
Joint definitions are used to construct joints.
Definition: b2Joint.h:74
b2WeldJoint::Dump
void Dump()
Dump to b2Log.
Definition: b2WeldJoint.cpp:329
b2WeldJoint::SetDampingRatio
void SetDampingRatio(float32 ratio)
Set/get damping ratio.
Definition: b2WeldJoint.h:85
b2WeldJointDef::localAnchorA
b2Vec2 localAnchorA
The local anchor point relative to bodyA's origin.
Definition: b2WeldJoint.h:44
b2Body
A rigid body. These are created via b2World::CreateBody.
Definition: b2Body.h:126
b2WeldJoint::GetAnchorB
b2Vec2 GetAnchorB() const
Get the anchor point on bodyB in world coordinates.
Definition: b2WeldJoint.cpp:313
b2WeldJoint::GetReferenceAngle
float32 GetReferenceAngle() const
Get the reference angle.
Definition: b2WeldJoint.h:78
b2Vec2
A 2D column vector.
Definition: b2Math.h:53
b2WeldJointDef::referenceAngle
float32 referenceAngle
The bodyB angle minus bodyA angle in the reference state (radians).
Definition: b2WeldJoint.h:50
b2WeldJoint::GetAnchorA
b2Vec2 GetAnchorA() const
Get the anchor point on bodyA in world coordinates.
Definition: b2WeldJoint.cpp:308
b2WeldJointDef::dampingRatio
float32 dampingRatio
The damping ratio. 0 = no damping, 1 = critical damping.
Definition: b2WeldJoint.h:57
b2WeldJointDef::Initialize
void Initialize(b2Body *bodyA, b2Body *bodyB, const b2Vec2 &anchor)
Definition: b2WeldJoint.cpp:37