Box2D: /build/box2d/src/box2d-2.4.1/include/box2d/b2_distance_joint.h Source File

| Box2D 2.4.1 A 2D physics engine for games

b2_distance_joint.h
1 // MIT License
2
3 // Copyright (c) 2019 Erin Catto
4
5 // Permission is hereby granted, free of charge, to any person obtaining a copy
6 // of this software and associated documentation files (the "Software"), to deal
7 // in the Software without restriction, including without limitation the rights
8 // to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
9 // copies of the Software, and to permit persons to whom the Software is
10 // furnished to do so, subject to the following conditions:
11
12 // The above copyright notice and this permission notice shall be included in all
13 // copies or substantial portions of the Software.
14
15 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
16 // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
17 // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
18 // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
19 // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
20 // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
21 // SOFTWARE.
22
23 #ifndef B2_DISTANCE_JOINT_H
24 #define B2_DISTANCE_JOINT_H
25
26 #include "b2_api.h"
27 #include "b2_joint.h"
28
33 struct B2_API b2DistanceJointDef : public b2JointDef
34 {
35 b2DistanceJointDef()
36 {
37 type = e_distanceJoint;
38 localAnchorA.Set(0.0f, 0.0f);
39 localAnchorB.Set(0.0f, 0.0f);
40 length = 1.0f;
41 minLength = 0.0f;
42 maxLength = FLT_MAX;
43 stiffness = 0.0f;
44 damping = 0.0f;
45 }
46
49 void Initialize(b2Body* bodyA, b2Body* bodyB,
50 const b2Vec2& anchorA, const b2Vec2& anchorB);
51
53 b2Vec2 localAnchorA;
54
56 b2Vec2 localAnchorB;
57
59 float length;
60
62 float minLength;
63
65 float maxLength;
66
68 float stiffness;
69
71 float damping;
72 };
73
76 class B2_API b2DistanceJoint : public b2Joint
77 {
78 public:
79
80 b2Vec2 GetAnchorA() const override;
81 b2Vec2 GetAnchorB() const override;
82
85 b2Vec2 GetReactionForce(float inv_dt) const override;
86
89 float GetReactionTorque(float inv_dt) const override;
90
92 const b2Vec2& GetLocalAnchorA() const { return m_localAnchorA; }
93
95 const b2Vec2& GetLocalAnchorB() const { return m_localAnchorB; }
96
98 float GetLength() const { return m_length; }
99
102 float SetLength(float length);
103
105 float GetMinLength() const { return m_minLength; }
106
109 float SetMinLength(float minLength);
110
112 float GetMaxLength() const { return m_maxLength; }
113
116 float SetMaxLength(float maxLength);
117
119 float GetCurrentLength() const;
120
122 void SetStiffness(float stiffness) { m_stiffness = stiffness; }
123 float GetStiffness() const { return m_stiffness; }
124
126 void SetDamping(float damping) { m_damping = damping; }
127 float GetDamping() const { return m_damping; }
128
130 void Dump() override;
131
133 void Draw(b2Draw* draw) const override;
134
135 protected:
136
137 friend class b2Joint;
138 b2DistanceJoint(const b2DistanceJointDef* data);
139
140 void InitVelocityConstraints(const b2SolverData& data) override;
141 void SolveVelocityConstraints(const b2SolverData& data) override;
142 bool SolvePositionConstraints(const b2SolverData& data) override;
143
144 float m_stiffness;
145 float m_damping;
146 float m_bias;
147 float m_length;
148 float m_minLength;
149 float m_maxLength;
150
151 // Solver shared
152 b2Vec2 m_localAnchorA;
153 b2Vec2 m_localAnchorB;
154 float m_gamma;
155 float m_impulse;
156 float m_lowerImpulse;
157 float m_upperImpulse;
158
159 // Solver temp
160 int32 m_indexA;
161 int32 m_indexB;
162 b2Vec2 m_u;
163 b2Vec2 m_rA;
164 b2Vec2 m_rB;
165 b2Vec2 m_localCenterA;
166 b2Vec2 m_localCenterB;
167 float m_currentLength;
168 float m_invMassA;
169 float m_invMassB;
170 float m_invIA;
171 float m_invIB;
172 float m_softMass;
173 float m_mass;
174 };
175
176 #endif
b2Vec2
A 2D column vector.
Definition: b2_math.h:42
b2Body
A rigid body. These are created via b2World::CreateBody.
Definition: b2_body.h:129
b2DistanceJoint::GetMaxLength
float GetMaxLength() const
Get the maximum length.
Definition: b2_distance_joint.h:112
b2DistanceJointDef::minLength
float minLength
Minimum length. Clamped to a stable minimum value.
Definition: b2_distance_joint.h:62
b2DistanceJoint::GetAnchorB
b2Vec2 GetAnchorB() const override
Get the anchor point on bodyB in world coordinates.
b2DistanceJoint::SetMinLength
float SetMinLength(float minLength)
b2DistanceJoint
Definition: b2_distance_joint.h:77
b2DistanceJoint::SetMaxLength
float SetMaxLength(float maxLength)
b2DistanceJoint::GetLocalAnchorA
const b2Vec2 & GetLocalAnchorA() const
The local anchor point relative to bodyA's origin.
Definition: b2_distance_joint.h:92
b2Draw
Definition: b2_draw.h:49
b2DistanceJoint::SetDamping
void SetDamping(float damping)
Set/get linear damping in N*s/m.
Definition: b2_distance_joint.h:126
b2JointDef
Joint definitions are used to construct joints.
Definition: b2_joint.h:73
b2DistanceJoint::GetLocalAnchorB
const b2Vec2 & GetLocalAnchorB() const
The local anchor point relative to bodyB's origin.
Definition: b2_distance_joint.h:95
b2DistanceJointDef::localAnchorA
b2Vec2 localAnchorA
The local anchor point relative to bodyA's origin.
Definition: b2_distance_joint.h:53
b2DistanceJoint::Draw
void Draw(b2Draw *draw) const override
Debug draw this joint.
b2DistanceJointDef::damping
float damping
The linear damping in N*s/m.
Definition: b2_distance_joint.h:71
b2DistanceJoint::Dump
void Dump() override
Dump joint to dmLog.
b2DistanceJointDef::length
float length
The rest length of this joint. Clamped to a stable minimum value.
Definition: b2_distance_joint.h:59
b2DistanceJointDef::stiffness
float stiffness
The linear stiffness in N/m.
Definition: b2_distance_joint.h:68
b2DistanceJoint::SetLength
float SetLength(float length)
b2DistanceJoint::GetCurrentLength
float GetCurrentLength() const
Get the current length.
b2DistanceJoint::GetLength
float GetLength() const
Get the rest length.
Definition: b2_distance_joint.h:98
b2DistanceJoint::GetReactionTorque
float GetReactionTorque(float inv_dt) const override
b2DistanceJoint::GetAnchorA
b2Vec2 GetAnchorA() const override
Get the anchor point on bodyA in world coordinates.
b2SolverData
Solver Data.
Definition: b2_time_step.h:68
b2DistanceJoint::GetReactionForce
b2Vec2 GetReactionForce(float inv_dt) const override
b2DistanceJoint::GetMinLength
float GetMinLength() const
Get the minimum length.
Definition: b2_distance_joint.h:105
b2DistanceJointDef::localAnchorB
b2Vec2 localAnchorB
The local anchor point relative to bodyB's origin.
Definition: b2_distance_joint.h:56
b2DistanceJoint::SetStiffness
void SetStiffness(float stiffness)
Set/get the linear stiffness in N/m.
Definition: b2_distance_joint.h:122
b2Joint
Definition: b2_joint.h:111
b2DistanceJointDef::maxLength
float maxLength
Maximum length. Must be greater than or equal to the minimum length.
Definition: b2_distance_joint.h:65
b2DistanceJointDef
Definition: b2_distance_joint.h:34
b2DistanceJointDef::Initialize
void Initialize(b2Body *bodyA, b2Body *bodyB, const b2Vec2 &anchorA, const b2Vec2 &anchorB)