Box2D 2.3.0 A 2D Physics Engine for Games

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b2DistanceJoint.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_DISTANCE_JOINT_H
20 #define B2_DISTANCE_JOINT_H
21
22 #include <Box2D/Dynamics/Joints/b2Joint.h>
23
30 struct b2DistanceJointDef : public b2JointDef
31 {
32 b2DistanceJointDef()
33 {
34 type = e_distanceJoint;
35 localAnchorA.Set(0.0f, 0.0f);
36 localAnchorB.Set(0.0f, 0.0f);
37 length = 1.0f;
38 frequencyHz = 0.0f;
39 dampingRatio = 0.0f;
40 }
41
44 void Initialize(b2Body* bodyA, b2Body* bodyB,
45 const b2Vec2& anchorA, const b2Vec2& anchorB);
46
48 b2Vec2 localAnchorA;
49
51 b2Vec2 localAnchorB;
52
54 float32 length;
55
58 float32 frequencyHz;
59
61 float32 dampingRatio;
62 };
63
67 class b2DistanceJoint : public b2Joint
68 {
69 public:
70
71 b2Vec2 GetAnchorA() const;
72 b2Vec2 GetAnchorB() const;
73
76 b2Vec2 GetReactionForce(float32 inv_dt) const;
77
80 float32 GetReactionTorque(float32 inv_dt) const;
81
83 const b2Vec2& GetLocalAnchorA() const { return m_localAnchorA; }
84
86 const b2Vec2& GetLocalAnchorB() const { return m_localAnchorB; }
87
90 void SetLength(float32 length);
91 float32 GetLength() const;
92
94 void SetFrequency(float32 hz);
95 float32 GetFrequency() const;
96
98 void SetDampingRatio(float32 ratio);
99 float32 GetDampingRatio() const;
100
102 void Dump();
103
104 protected:
105
106 friend class b2Joint;
107 b2DistanceJoint(const b2DistanceJointDef* data);
108
109 void InitVelocityConstraints(const b2SolverData& data);
110 void SolveVelocityConstraints(const b2SolverData& data);
111 bool SolvePositionConstraints(const b2SolverData& data);
112
113 float32 m_frequencyHz;
114 float32 m_dampingRatio;
115 float32 m_bias;
116
117 // Solver shared
118 b2Vec2 m_localAnchorA;
119 b2Vec2 m_localAnchorB;
120 float32 m_gamma;
121 float32 m_impulse;
122 float32 m_length;
123
124 // Solver temp
125 int32 m_indexA;
126 int32 m_indexB;
127 b2Vec2 m_u;
128 b2Vec2 m_rA;
129 b2Vec2 m_rB;
130 b2Vec2 m_localCenterA;
131 b2Vec2 m_localCenterB;
132 float32 m_invMassA;
133 float32 m_invMassB;
134 float32 m_invIA;
135 float32 m_invIB;
136 float32 m_mass;
137 };
138
139 inline void b2DistanceJoint::SetLength(float32 length)
140 {
141 m_length = length;
142 }
143
144 inline float32 b2DistanceJoint::GetLength() const
145 {
146 return m_length;
147 }
148
149 inline void b2DistanceJoint::SetFrequency(float32 hz)
150 {
151 m_frequencyHz = hz;
152 }
153
154 inline float32 b2DistanceJoint::GetFrequency() const
155 {
156 return m_frequencyHz;
157 }
158
159 inline void b2DistanceJoint::SetDampingRatio(float32 ratio)
160 {
161 m_dampingRatio = ratio;
162 }
163
164 inline float32 b2DistanceJoint::GetDampingRatio() const
165 {
166 return m_dampingRatio;
167 }
168
169 #endif
b2DistanceJointDef::Initialize
void Initialize(b2Body *bodyA, b2Body *bodyB, const b2Vec2 &anchorA, const b2Vec2 &anchorB)
Definition: b2DistanceJoint.cpp:38
b2JointDef::bodyA
b2Body * bodyA
The first attached body.
Definition: b2Joint.h:92
b2DistanceJointDef::localAnchorA
b2Vec2 localAnchorA
The local anchor point relative to bodyA&#39;s origin.
Definition: b2DistanceJoint.h:48
b2JointDef::bodyB
b2Body * bodyB
The second attached body.
Definition: b2Joint.h:95
b2DistanceJoint::GetReactionForce
b2Vec2 GetReactionForce(float32 inv_dt) const
Definition: b2DistanceJoint.cpp:233
b2Joint
Definition: b2Joint.h:103
b2DistanceJoint::SetLength
void SetLength(float32 length)
Definition: b2DistanceJoint.h:139
b2Vec2::Set
void Set(float32 x_, float32 y_)
Set this vector to some specified coordinates.
Definition: b2Math.h:65
b2DistanceJoint::GetReactionTorque
float32 GetReactionTorque(float32 inv_dt) const
Definition: b2DistanceJoint.cpp:239
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
b2DistanceJoint::Dump
void Dump()
Dump joint to dmLog.
Definition: b2DistanceJoint.cpp:245
b2DistanceJointDef::length
float32 length
The natural length between the anchor points.
Definition: b2DistanceJoint.h:54
b2DistanceJoint
Definition: b2DistanceJoint.h:67
b2DistanceJointDef::frequencyHz
float32 frequencyHz
Definition: b2DistanceJoint.h:58
b2JointDef
Joint definitions are used to construct joints.
Definition: b2Joint.h:74
b2DistanceJoint::GetLocalAnchorA
const b2Vec2 & GetLocalAnchorA() const
The local anchor point relative to bodyA&#39;s origin.
Definition: b2DistanceJoint.h:83
b2DistanceJoint::GetAnchorB
b2Vec2 GetAnchorB() const
Get the anchor point on bodyB in world coordinates.
Definition: b2DistanceJoint.cpp:228
b2Body
A rigid body. These are created via b2World::CreateBody.
Definition: b2Body.h:126
b2DistanceJointDef
Definition: b2DistanceJoint.h:30
b2DistanceJointDef::dampingRatio
float32 dampingRatio
The damping ratio. 0 = no damping, 1 = critical damping.
Definition: b2DistanceJoint.h:61
b2DistanceJoint::SetDampingRatio
void SetDampingRatio(float32 ratio)
Set/get damping ratio.
Definition: b2DistanceJoint.h:159
b2DistanceJoint::GetAnchorA
b2Vec2 GetAnchorA() const
Get the anchor point on bodyA in world coordinates.
Definition: b2DistanceJoint.cpp:223
b2DistanceJoint::GetLocalAnchorB
const b2Vec2 & GetLocalAnchorB() const
The local anchor point relative to bodyB&#39;s origin.
Definition: b2DistanceJoint.h:86
b2DistanceJointDef::localAnchorB
b2Vec2 localAnchorB
The local anchor point relative to bodyB&#39;s origin.
Definition: b2DistanceJoint.h:51
b2Vec2
A 2D column vector.
Definition: b2Math.h:53
b2DistanceJoint::SetFrequency
void SetFrequency(float32 hz)
Set/get frequency in Hz.
Definition: b2DistanceJoint.h:149