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Diffstat (limited to 'src/3rdparty/Box2D/Dynamics/Joints/b2WheelJoint.h')
| -rw-r--r-- | src/3rdparty/Box2D/Dynamics/Joints/b2WheelJoint.h | 216 |
1 files changed, 216 insertions, 0 deletions
diff --git a/src/3rdparty/Box2D/Dynamics/Joints/b2WheelJoint.h b/src/3rdparty/Box2D/Dynamics/Joints/b2WheelJoint.h new file mode 100644 index 0000000..be7ad66 --- /dev/null +++ b/src/3rdparty/Box2D/Dynamics/Joints/b2WheelJoint.h @@ -0,0 +1,216 @@ +/* +* Copyright (c) 2006-2011 Erin Catto http://www.box2d.org +* +* This software is provided 'as-is', without any express or implied +* warranty. In no event will the authors be held liable for any damages +* arising from the use of this software. +* Permission is granted to anyone to use this software for any purpose, +* including commercial applications, and to alter it and redistribute it +* freely, subject to the following restrictions: +* 1. The origin of this software must not be misrepresented; you must not +* claim that you wrote the original software. If you use this software +* in a product, an acknowledgment in the product documentation would be +* appreciated but is not required. +* 2. Altered source versions must be plainly marked as such, and must not be +* misrepresented as being the original software. +* 3. This notice may not be removed or altered from any source distribution. +*/ + +#ifndef B2_WHEEL_JOINT_H +#define B2_WHEEL_JOINT_H + +#include "Box2D/Dynamics/Joints/b2Joint.h" + +/// Wheel joint definition. This requires defining a line of +/// motion using an axis and an anchor point. The definition uses local +/// anchor points and a local axis so that the initial configuration +/// can violate the constraint slightly. The joint translation is zero +/// when the local anchor points coincide in world space. Using local +/// anchors and a local axis helps when saving and loading a game. +struct b2WheelJointDef : public b2JointDef +{ + b2WheelJointDef() + { + type = e_wheelJoint; + localAnchorA.SetZero(); + localAnchorB.SetZero(); + localAxisA.Set(1.0f, 0.0f); + enableMotor = false; + maxMotorTorque = 0.0f; + motorSpeed = 0.0f; + frequencyHz = 2.0f; + dampingRatio = 0.7f; + } + + /// Initialize the bodies, anchors, axis, and reference angle using the world + /// anchor and world axis. + void Initialize(b2Body* bodyA, b2Body* bodyB, const b2Vec2& anchor, const b2Vec2& axis); + + /// The local anchor point relative to bodyA's origin. + b2Vec2 localAnchorA; + + /// The local anchor point relative to bodyB's origin. + b2Vec2 localAnchorB; + + /// The local translation axis in bodyA. + b2Vec2 localAxisA; + + /// Enable/disable the joint motor. + bool enableMotor; + + /// The maximum motor torque, usually in N-m. + float32 maxMotorTorque; + + /// The desired motor speed in radians per second. + float32 motorSpeed; + + /// Suspension frequency, zero indicates no suspension + float32 frequencyHz; + + /// Suspension damping ratio, one indicates critical damping + float32 dampingRatio; +}; + +/// A wheel joint. This joint provides two degrees of freedom: translation +/// along an axis fixed in bodyA and rotation in the plane. In other words, it is a point to +/// line constraint with a rotational motor and a linear spring/damper. +/// This joint is designed for vehicle suspensions. +class b2WheelJoint : public b2Joint +{ +public: + b2Vec2 GetAnchorA() const override; + b2Vec2 GetAnchorB() const override; + + b2Vec2 GetReactionForce(float32 inv_dt) const override; + float32 GetReactionTorque(float32 inv_dt) const override; + + /// The local anchor point relative to bodyA's origin. + const b2Vec2& GetLocalAnchorA() const { return m_localAnchorA; } + + /// The local anchor point relative to bodyB's origin. + const b2Vec2& GetLocalAnchorB() const { return m_localAnchorB; } + + /// The local joint axis relative to bodyA. + const b2Vec2& GetLocalAxisA() const { return m_localXAxisA; } + + /// Get the current joint translation, usually in meters. + float32 GetJointTranslation() const; + + /// Get the current joint linear speed, usually in meters per second. + float32 GetJointLinearSpeed() const; + + /// Get the current joint angle in radians. + float32 GetJointAngle() const; + + /// Get the current joint angular speed in radians per second. + float32 GetJointAngularSpeed() const; + + /// Is the joint motor enabled? + bool IsMotorEnabled() const; + + /// Enable/disable the joint motor. + void EnableMotor(bool flag); + + /// Set the motor speed, usually in radians per second. + void SetMotorSpeed(float32 speed); + + /// Get the motor speed, usually in radians per second. + float32 GetMotorSpeed() const; + + /// Set/Get the maximum motor force, usually in N-m. + void SetMaxMotorTorque(float32 torque); + float32 GetMaxMotorTorque() const; + + /// Get the current motor torque given the inverse time step, usually in N-m. + float32 GetMotorTorque(float32 inv_dt) const; + + /// Set/Get the spring frequency in hertz. Setting the frequency to zero disables the spring. + void SetSpringFrequencyHz(float32 hz); + float32 GetSpringFrequencyHz() const; + + /// Set/Get the spring damping ratio + void SetSpringDampingRatio(float32 ratio); + float32 GetSpringDampingRatio() const; + + /// Dump to b2Log + void Dump() override; + +protected: + + friend class b2Joint; + b2WheelJoint(const b2WheelJointDef* def); + + void InitVelocityConstraints(const b2SolverData& data) override; + void SolveVelocityConstraints(const b2SolverData& data) override; + bool SolvePositionConstraints(const b2SolverData& data) override; + + float32 m_frequencyHz; + float32 m_dampingRatio; + + // Solver shared + b2Vec2 m_localAnchorA; + b2Vec2 m_localAnchorB; + b2Vec2 m_localXAxisA; + b2Vec2 m_localYAxisA; + + float32 m_impulse; + float32 m_motorImpulse; + float32 m_springImpulse; + + float32 m_maxMotorTorque; + float32 m_motorSpeed; + bool m_enableMotor; + + // Solver temp + int32 m_indexA; + int32 m_indexB; + b2Vec2 m_localCenterA; + b2Vec2 m_localCenterB; + float32 m_invMassA; + float32 m_invMassB; + float32 m_invIA; + float32 m_invIB; + + b2Vec2 m_ax, m_ay; + float32 m_sAx, m_sBx; + float32 m_sAy, m_sBy; + + float32 m_mass; + float32 m_motorMass; + float32 m_springMass; + + float32 m_bias; + float32 m_gamma; +}; + +inline float32 b2WheelJoint::GetMotorSpeed() const +{ + return m_motorSpeed; +} + +inline float32 b2WheelJoint::GetMaxMotorTorque() const +{ + return m_maxMotorTorque; +} + +inline void b2WheelJoint::SetSpringFrequencyHz(float32 hz) +{ + m_frequencyHz = hz; +} + +inline float32 b2WheelJoint::GetSpringFrequencyHz() const +{ + return m_frequencyHz; +} + +inline void b2WheelJoint::SetSpringDampingRatio(float32 ratio) +{ + m_dampingRatio = ratio; +} + +inline float32 b2WheelJoint::GetSpringDampingRatio() const +{ + return m_dampingRatio; +} + +#endif |