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Diffstat (limited to 'src/3rdparty/Box2D/Dynamics/Joints/b2MouseJoint.h')
-rw-r--r-- | src/3rdparty/Box2D/Dynamics/Joints/b2MouseJoint.h | 129 |
1 files changed, 129 insertions, 0 deletions
diff --git a/src/3rdparty/Box2D/Dynamics/Joints/b2MouseJoint.h b/src/3rdparty/Box2D/Dynamics/Joints/b2MouseJoint.h new file mode 100644 index 0000000..7441978 --- /dev/null +++ b/src/3rdparty/Box2D/Dynamics/Joints/b2MouseJoint.h @@ -0,0 +1,129 @@ +/* +* Copyright (c) 2006-2007 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_MOUSE_JOINT_H +#define B2_MOUSE_JOINT_H + +#include "Box2D/Dynamics/Joints/b2Joint.h" + +/// Mouse joint definition. This requires a world target point, +/// tuning parameters, and the time step. +struct b2MouseJointDef : public b2JointDef +{ + b2MouseJointDef() + { + type = e_mouseJoint; + target.Set(0.0f, 0.0f); + maxForce = 0.0f; + frequencyHz = 5.0f; + dampingRatio = 0.7f; + } + + /// The initial world target point. This is assumed + /// to coincide with the body anchor initially. + b2Vec2 target; + + /// The maximum constraint force that can be exerted + /// to move the candidate body. Usually you will express + /// as some multiple of the weight (multiplier * mass * gravity). + float32 maxForce; + + /// The response speed. + float32 frequencyHz; + + /// The damping ratio. 0 = no damping, 1 = critical damping. + float32 dampingRatio; +}; + +/// A mouse joint is used to make a point on a body track a +/// specified world point. This a soft constraint with a maximum +/// force. This allows the constraint to stretch and without +/// applying huge forces. +/// NOTE: this joint is not documented in the manual because it was +/// developed to be used in the testbed. If you want to learn how to +/// use the mouse joint, look at the testbed. +class b2MouseJoint : public b2Joint +{ +public: + + /// Implements b2Joint. + b2Vec2 GetAnchorA() const override; + + /// Implements b2Joint. + b2Vec2 GetAnchorB() const override; + + /// Implements b2Joint. + b2Vec2 GetReactionForce(float32 inv_dt) const override; + + /// Implements b2Joint. + float32 GetReactionTorque(float32 inv_dt) const override; + + /// Use this to update the target point. + void SetTarget(const b2Vec2& target); + const b2Vec2& GetTarget() const; + + /// Set/get the maximum force in Newtons. + void SetMaxForce(float32 force); + float32 GetMaxForce() const; + + /// Set/get the frequency in Hertz. + void SetFrequency(float32 hz); + float32 GetFrequency() const; + + /// Set/get the damping ratio (dimensionless). + void SetDampingRatio(float32 ratio); + float32 GetDampingRatio() const; + + /// The mouse joint does not support dumping. + void Dump() override { b2Log("Mouse joint dumping is not supported.\n"); } + + /// Implement b2Joint::ShiftOrigin + void ShiftOrigin(const b2Vec2& newOrigin) override; + +protected: + friend class b2Joint; + + b2MouseJoint(const b2MouseJointDef* def); + + void InitVelocityConstraints(const b2SolverData& data) override; + void SolveVelocityConstraints(const b2SolverData& data) override; + bool SolvePositionConstraints(const b2SolverData& data) override; + + b2Vec2 m_localAnchorB; + b2Vec2 m_targetA; + float32 m_frequencyHz; + float32 m_dampingRatio; + float32 m_beta; + + // Solver shared + b2Vec2 m_impulse; + float32 m_maxForce; + float32 m_gamma; + + // Solver temp + int32 m_indexA; + int32 m_indexB; + b2Vec2 m_rB; + b2Vec2 m_localCenterB; + float32 m_invMassB; + float32 m_invIB; + b2Mat22 m_mass; + b2Vec2 m_C; +}; + +#endif |