Box2D: /build/box2d/src/box2d-adaedf1772ede7420bc9ee569c8cba7952db91a0/include/box2d/b2_pulley_joint.h Source File

| Box2D 2.4.0 A 2D physics engine for games

b2_pulley_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_PULLEY_JOINT_H
24 #define B2_PULLEY_JOINT_H
25
26 #include "b2_api.h"
27 #include "b2_joint.h"
28
29 const float b2_minPulleyLength = 2.0f;
30
33 struct B2_API b2PulleyJointDef : public b2JointDef
34 {
35 b2PulleyJointDef()
36 {
37 type = e_pulleyJoint;
38 groundAnchorA.Set(-1.0f, 1.0f);
39 groundAnchorB.Set(1.0f, 1.0f);
40 localAnchorA.Set(-1.0f, 0.0f);
41 localAnchorB.Set(1.0f, 0.0f);
42 lengthA = 0.0f;
43 lengthB = 0.0f;
44 ratio = 1.0f;
45 collideConnected = true;
46 }
47
49 void Initialize(b2Body* bodyA, b2Body* bodyB,
50 const b2Vec2& groundAnchorA, const b2Vec2& groundAnchorB,
51 const b2Vec2& anchorA, const b2Vec2& anchorB,
52 float ratio);
53
55 b2Vec2 groundAnchorA;
56
58 b2Vec2 groundAnchorB;
59
61 b2Vec2 localAnchorA;
62
64 b2Vec2 localAnchorB;
65
67 float lengthA;
68
70 float lengthB;
71
73 float ratio;
74 };
75
84 class B2_API b2PulleyJoint : public b2Joint
85 {
86 public:
87 b2Vec2 GetAnchorA() const override;
88 b2Vec2 GetAnchorB() const override;
89
90 b2Vec2 GetReactionForce(float inv_dt) const override;
91 float GetReactionTorque(float inv_dt) const override;
92
94 b2Vec2 GetGroundAnchorA() const;
95
97 b2Vec2 GetGroundAnchorB() const;
98
100 float GetLengthA() const;
101
103 float GetLengthB() const;
104
106 float GetRatio() const;
107
109 float GetCurrentLengthA() const;
110
112 float GetCurrentLengthB() const;
113
115 void Dump() override;
116
118 void ShiftOrigin(const b2Vec2& newOrigin) override;
119
120 protected:
121
122 friend class b2Joint;
123 b2PulleyJoint(const b2PulleyJointDef* data);
124
125 void InitVelocityConstraints(const b2SolverData& data) override;
126 void SolveVelocityConstraints(const b2SolverData& data) override;
127 bool SolvePositionConstraints(const b2SolverData& data) override;
128
129 b2Vec2 m_groundAnchorA;
130 b2Vec2 m_groundAnchorB;
131 float m_lengthA;
132 float m_lengthB;
133
134 // Solver shared
135 b2Vec2 m_localAnchorA;
136 b2Vec2 m_localAnchorB;
137 float m_constant;
138 float m_ratio;
139 float m_impulse;
140
141 // Solver temp
142 int32 m_indexA;
143 int32 m_indexB;
144 b2Vec2 m_uA;
145 b2Vec2 m_uB;
146 b2Vec2 m_rA;
147 b2Vec2 m_rB;
148 b2Vec2 m_localCenterA;
149 b2Vec2 m_localCenterB;
150 float m_invMassA;
151 float m_invMassB;
152 float m_invIA;
153 float m_invIB;
154 float m_mass;
155 };
156
157 #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:133
b2PulleyJoint::GetCurrentLengthB
float GetCurrentLengthB() const
Get the current length of the segment attached to bodyB.
b2PulleyJoint::GetAnchorA
b2Vec2 GetAnchorA() const override
Get the anchor point on bodyA in world coordinates.
b2PulleyJointDef::groundAnchorB
b2Vec2 groundAnchorB
The second ground anchor in world coordinates. This point never moves.
Definition: b2_pulley_joint.h:58
b2PulleyJoint::ShiftOrigin
void ShiftOrigin(const b2Vec2 &newOrigin) override
Implement b2Joint::ShiftOrigin.
b2PulleyJointDef::lengthB
float lengthB
The a reference length for the segment attached to bodyB.
Definition: b2_pulley_joint.h:70
b2PulleyJoint::GetReactionForce
b2Vec2 GetReactionForce(float inv_dt) const override
Get the reaction force on bodyB at the joint anchor in Newtons.
b2PulleyJoint::GetLengthA
float GetLengthA() const
Get the current length of the segment attached to bodyA.
b2PulleyJointDef
Definition: b2_pulley_joint.h:34
b2JointDef
Joint definitions are used to construct joints.
Definition: b2_joint.h:73
b2PulleyJointDef::localAnchorB
b2Vec2 localAnchorB
The local anchor point relative to bodyB's origin.
Definition: b2_pulley_joint.h:64
b2PulleyJoint::Dump
void Dump() override
Dump joint to dmLog.
b2PulleyJointDef::Initialize
void Initialize(b2Body *bodyA, b2Body *bodyB, const b2Vec2 &groundAnchorA, const b2Vec2 &groundAnchorB, const b2Vec2 &anchorA, const b2Vec2 &anchorB, float ratio)
Initialize the bodies, anchors, lengths, max lengths, and ratio using the world anchors.
b2PulleyJoint::GetRatio
float GetRatio() const
Get the pulley ratio.
b2PulleyJointDef::ratio
float ratio
The pulley ratio, used to simulate a block-and-tackle.
Definition: b2_pulley_joint.h:73
b2PulleyJoint::GetGroundAnchorA
b2Vec2 GetGroundAnchorA() const
Get the first ground anchor.
b2PulleyJointDef::groundAnchorA
b2Vec2 groundAnchorA
The first ground anchor in world coordinates. This point never moves.
Definition: b2_pulley_joint.h:55
b2PulleyJoint::GetGroundAnchorB
b2Vec2 GetGroundAnchorB() const
Get the second ground anchor.
b2PulleyJoint::GetReactionTorque
float GetReactionTorque(float inv_dt) const override
Get the reaction torque on bodyB in N*m.
b2PulleyJointDef::localAnchorA
b2Vec2 localAnchorA
The local anchor point relative to bodyA's origin.
Definition: b2_pulley_joint.h:61
b2SolverData
Solver Data.
Definition: b2_time_step.h:68
b2PulleyJoint::GetLengthB
float GetLengthB() const
Get the current length of the segment attached to bodyB.
b2Joint
Definition: b2_joint.h:112
b2PulleyJointDef::lengthA
float lengthA
The a reference length for the segment attached to bodyA.
Definition: b2_pulley_joint.h:67
b2PulleyJoint::GetCurrentLengthA
float GetCurrentLengthA() const
Get the current length of the segment attached to bodyA.
b2PulleyJoint::GetAnchorB
b2Vec2 GetAnchorB() const override
Get the anchor point on bodyB in world coordinates.
b2PulleyJoint
Definition: b2_pulley_joint.h:85