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Diffstat (limited to 'ThirdParty/Box2D/Dynamics/Joints/b2RopeJoint.h')
-rw-r--r-- | ThirdParty/Box2D/Dynamics/Joints/b2RopeJoint.h | 114 |
1 files changed, 114 insertions, 0 deletions
diff --git a/ThirdParty/Box2D/Dynamics/Joints/b2RopeJoint.h b/ThirdParty/Box2D/Dynamics/Joints/b2RopeJoint.h new file mode 100644 index 0000000..ef5d6f7 --- /dev/null +++ b/ThirdParty/Box2D/Dynamics/Joints/b2RopeJoint.h @@ -0,0 +1,114 @@ +/* +* 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_ROPE_JOINT_H +#define B2_ROPE_JOINT_H + +#include "Box2D/Dynamics/Joints/b2Joint.h" + +/// Rope joint definition. This requires two body anchor points and +/// a maximum lengths. +/// Note: by default the connected objects will not collide. +/// see collideConnected in b2JointDef. +struct b2RopeJointDef : public b2JointDef +{ + b2RopeJointDef() + { + type = e_ropeJoint; + localAnchorA.Set(-1.0f, 0.0f); + localAnchorB.Set(1.0f, 0.0f); + maxLength = 0.0f; + } + + /// The local anchor point relative to bodyA's origin. + b2Vec2 localAnchorA; + + /// The local anchor point relative to bodyB's origin. + b2Vec2 localAnchorB; + + /// The maximum length of the rope. + /// Warning: this must be larger than b2_linearSlop or + /// the joint will have no effect. + float32 maxLength; +}; + +/// A rope joint enforces a maximum distance between two points +/// on two bodies. It has no other effect. +/// Warning: if you attempt to change the maximum length during +/// the simulation you will get some non-physical behavior. +/// A model that would allow you to dynamically modify the length +/// would have some sponginess, so I chose not to implement it +/// that way. See b2DistanceJoint if you want to dynamically +/// control length. +class b2RopeJoint : 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; } + + /// Set/Get the maximum length of the rope. + void SetMaxLength(float32 length) { m_maxLength = length; } + float32 GetMaxLength() const; + + b2LimitState GetLimitState() const; + + /// Dump joint to dmLog + void Dump() override; + +protected: + + friend class b2Joint; + b2RopeJoint(const b2RopeJointDef* data); + + void InitVelocityConstraints(const b2SolverData& data) override; + void SolveVelocityConstraints(const b2SolverData& data) override; + bool SolvePositionConstraints(const b2SolverData& data) override; + + // Solver shared + b2Vec2 m_localAnchorA; + b2Vec2 m_localAnchorB; + float32 m_maxLength; + float32 m_length; + float32 m_impulse; + + // Solver temp + int32 m_indexA; + int32 m_indexB; + b2Vec2 m_u; + b2Vec2 m_rA; + b2Vec2 m_rB; + b2Vec2 m_localCenterA; + b2Vec2 m_localCenterB; + float32 m_invMassA; + float32 m_invMassB; + float32 m_invIA; + float32 m_invIB; + float32 m_mass; + b2LimitState m_state; +}; + +#endif |