Box2D: /build/box2d/src/box2d-adaedf1772ede7420bc9ee569c8cba7952db91a0/include/box2d/b2_wheel_joint.h Source File

| Box2D 2.4.0 A 2D physics engine for games

b2_wheel_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_WHEEL_JOINT_H
24 #define B2_WHEEL_JOINT_H
25
26 #include "b2_api.h"
27 #include "b2_joint.h"
28
35 struct B2_API b2WheelJointDef : public b2JointDef
36 {
37 b2WheelJointDef()
38 {
39 type = e_wheelJoint;
40 localAnchorA.SetZero();
41 localAnchorB.SetZero();
42 localAxisA.Set(1.0f, 0.0f);
43 enableLimit = false;
44 lowerTranslation = 0.0f;
45 upperTranslation = 0.0f;
46 enableMotor = false;
47 maxMotorTorque = 0.0f;
48 motorSpeed = 0.0f;
49 stiffness = 0.0f;
50 damping = 0.0f;
51 }
52
55 void Initialize(b2Body* bodyA, b2Body* bodyB, const b2Vec2& anchor, const b2Vec2& axis);
56
58 b2Vec2 localAnchorA;
59
61 b2Vec2 localAnchorB;
62
64 b2Vec2 localAxisA;
65
67 bool enableLimit;
68
70 float lowerTranslation;
71
73 float upperTranslation;
74
76 bool enableMotor;
77
79 float maxMotorTorque;
80
82 float motorSpeed;
83
85 float stiffness;
86
88 float damping;
89 };
90
95 class B2_API b2WheelJoint : public b2Joint
96 {
97 public:
98 b2Vec2 GetAnchorA() const override;
99 b2Vec2 GetAnchorB() const override;
100
101 b2Vec2 GetReactionForce(float inv_dt) const override;
102 float GetReactionTorque(float inv_dt) const override;
103
105 const b2Vec2& GetLocalAnchorA() const { return m_localAnchorA; }
106
108 const b2Vec2& GetLocalAnchorB() const { return m_localAnchorB; }
109
111 const b2Vec2& GetLocalAxisA() const { return m_localXAxisA; }
112
114 float GetJointTranslation() const;
115
117 float GetJointLinearSpeed() const;
118
120 float GetJointAngle() const;
121
123 float GetJointAngularSpeed() const;
124
126 bool IsLimitEnabled() const;
127
129 void EnableLimit(bool flag);
130
132 float GetLowerLimit() const;
133
135 float GetUpperLimit() const;
136
138 void SetLimits(float lower, float upper);
139
141 bool IsMotorEnabled() const;
142
144 void EnableMotor(bool flag);
145
147 void SetMotorSpeed(float speed);
148
150 float GetMotorSpeed() const;
151
153 void SetMaxMotorTorque(float torque);
154 float GetMaxMotorTorque() const;
155
157 float GetMotorTorque(float inv_dt) const;
158
160 void SetStiffness(float stiffness);
161 float GetStiffness() const;
162
164 void SetDamping(float damping);
165 float GetDamping() const;
166
168 void Dump() override;
169
171 void Draw(b2Draw* draw) const override;
172
173 protected:
174
175 friend class b2Joint;
176 b2WheelJoint(const b2WheelJointDef* def);
177
178 void InitVelocityConstraints(const b2SolverData& data) override;
179 void SolveVelocityConstraints(const b2SolverData& data) override;
180 bool SolvePositionConstraints(const b2SolverData& data) override;
181
182 b2Vec2 m_localAnchorA;
183 b2Vec2 m_localAnchorB;
184 b2Vec2 m_localXAxisA;
185 b2Vec2 m_localYAxisA;
186
187 float m_impulse;
188 float m_motorImpulse;
189 float m_springImpulse;
190
191 float m_lowerImpulse;
192 float m_upperImpulse;
193 float m_translation;
194 float m_lowerTranslation;
195 float m_upperTranslation;
196
197 float m_maxMotorTorque;
198 float m_motorSpeed;
199
200 bool m_enableLimit;
201 bool m_enableMotor;
202
203 float m_stiffness;
204 float m_damping;
205
206 // Solver temp
207 int32 m_indexA;
208 int32 m_indexB;
209 b2Vec2 m_localCenterA;
210 b2Vec2 m_localCenterB;
211 float m_invMassA;
212 float m_invMassB;
213 float m_invIA;
214 float m_invIB;
215
216 b2Vec2 m_ax, m_ay;
217 float m_sAx, m_sBx;
218 float m_sAy, m_sBy;
219
220 float m_mass;
221 float m_motorMass;
222 float m_axialMass;
223 float m_springMass;
224
225 float m_bias;
226 float m_gamma;
227
228 };
229
230 inline float b2WheelJoint::GetMotorSpeed() const
231 {
232 return m_motorSpeed;
233 }
234
235 inline float b2WheelJoint::GetMaxMotorTorque() const
236 {
237 return m_maxMotorTorque;
238 }
239
240 #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
b2WheelJointDef::Initialize
void Initialize(b2Body *bodyA, b2Body *bodyB, const b2Vec2 &anchor, const b2Vec2 &axis)
b2WheelJoint::EnableMotor
void EnableMotor(bool flag)
Enable/disable the joint motor.
b2Draw
Definition: b2_draw.h:49
b2WheelJoint::SetDamping
void SetDamping(float damping)
Access damping.
b2WheelJoint::GetMotorTorque
float GetMotorTorque(float inv_dt) const
Get the current motor torque given the inverse time step, usually in N-m.
b2JointDef
Joint definitions are used to construct joints.
Definition: b2_joint.h:73
b2WheelJointDef::localAnchorB
b2Vec2 localAnchorB
The local anchor point relative to bodyB's origin.
Definition: b2_wheel_joint.h:61
b2WheelJoint::GetJointTranslation
float GetJointTranslation() const
Get the current joint translation, usually in meters.
b2WheelJoint::GetLowerLimit
float GetLowerLimit() const
Get the lower joint translation limit, usually in meters.
b2WheelJointDef::upperTranslation
float upperTranslation
The upper translation limit, usually in meters.
Definition: b2_wheel_joint.h:73
b2WheelJoint
Definition: b2_wheel_joint.h:96
b2WheelJointDef::stiffness
float stiffness
Suspension stiffness. Typically in units N/m.
Definition: b2_wheel_joint.h:85
b2WheelJointDef::enableMotor
bool enableMotor
Enable/disable the joint motor.
Definition: b2_wheel_joint.h:76
b2WheelJoint::GetJointAngularSpeed
float GetJointAngularSpeed() const
Get the current joint angular speed in radians per second.
b2WheelJoint::Dump
void Dump() override
Dump to b2Log.
b2WheelJoint::GetJointLinearSpeed
float GetJointLinearSpeed() const
Get the current joint linear speed, usually in meters per second.
b2WheelJoint::GetMotorSpeed
float GetMotorSpeed() const
Get the motor speed, usually in radians per second.
Definition: b2_wheel_joint.h:230
b2WheelJoint::GetLocalAxisA
const b2Vec2 & GetLocalAxisA() const
The local joint axis relative to bodyA.
Definition: b2_wheel_joint.h:111
b2WheelJoint::IsLimitEnabled
bool IsLimitEnabled() const
Is the joint limit enabled?
b2WheelJoint::IsMotorEnabled
bool IsMotorEnabled() const
Is the joint motor enabled?
b2WheelJoint::SetLimits
void SetLimits(float lower, float upper)
Set the joint translation limits, usually in meters.
b2WheelJoint::Draw
void Draw(b2Draw *draw) const override
Debug draw this joint.
b2WheelJointDef::localAxisA
b2Vec2 localAxisA
The local translation axis in bodyA.
Definition: b2_wheel_joint.h:64
b2WheelJointDef::damping
float damping
Suspension damping. Typically in units of N*s/m.
Definition: b2_wheel_joint.h:88
b2WheelJoint::EnableLimit
void EnableLimit(bool flag)
Enable/disable the joint translation limit.
b2WheelJoint::GetAnchorB
b2Vec2 GetAnchorB() const override
Get the anchor point on bodyB in world coordinates.
b2WheelJoint::GetLocalAnchorA
const b2Vec2 & GetLocalAnchorA() const
The local anchor point relative to bodyA's origin.
Definition: b2_wheel_joint.h:105
b2WheelJointDef
Definition: b2_wheel_joint.h:36
b2WheelJoint::SetStiffness
void SetStiffness(float stiffness)
Access spring stiffness.
b2SolverData
Solver Data.
Definition: b2_time_step.h:68
b2WheelJoint::GetUpperLimit
float GetUpperLimit() const
Get the upper joint translation limit, usually in meters.
b2WheelJointDef::maxMotorTorque
float maxMotorTorque
The maximum motor torque, usually in N-m.
Definition: b2_wheel_joint.h:79
b2WheelJointDef::localAnchorA
b2Vec2 localAnchorA
The local anchor point relative to bodyA's origin.
Definition: b2_wheel_joint.h:58
b2WheelJointDef::enableLimit
bool enableLimit
Enable/disable the joint limit.
Definition: b2_wheel_joint.h:67
b2WheelJointDef::motorSpeed
float motorSpeed
The desired motor speed in radians per second.
Definition: b2_wheel_joint.h:82
b2WheelJoint::SetMotorSpeed
void SetMotorSpeed(float speed)
Set the motor speed, usually in radians per second.
b2Joint
Definition: b2_joint.h:112
b2WheelJoint::GetReactionTorque
float GetReactionTorque(float inv_dt) const override
Get the reaction torque on bodyB in N*m.
b2WheelJointDef::lowerTranslation
float lowerTranslation
The lower translation limit, usually in meters.
Definition: b2_wheel_joint.h:70
b2WheelJoint::GetAnchorA
b2Vec2 GetAnchorA() const override
Get the anchor point on bodyA in world coordinates.
b2WheelJoint::GetReactionForce
b2Vec2 GetReactionForce(float inv_dt) const override
Get the reaction force on bodyB at the joint anchor in Newtons.
b2WheelJoint::SetMaxMotorTorque
void SetMaxMotorTorque(float torque)
Set/Get the maximum motor force, usually in N-m.
b2WheelJoint::GetLocalAnchorB
const b2Vec2 & GetLocalAnchorB() const
The local anchor point relative to bodyB's origin.
Definition: b2_wheel_joint.h:108
b2WheelJoint::GetJointAngle
float GetJointAngle() const
Get the current joint angle in radians.