126 lines
		
	
	
		
			3.5 KiB
		
	
	
	
		
			C++
		
	
	
	
			
		
		
	
	
			126 lines
		
	
	
		
			3.5 KiB
		
	
	
	
		
			C++
		
	
	
	
| /*
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| * Copyright (c) 2006-2011 Erin Catto http://www.box2d.org
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| *
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| * This software is provided 'as-is', without any express or implied
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| * warranty.  In no event will the authors be held liable for any damages
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| * arising from the use of this software.
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| * Permission is granted to anyone to use this software for any purpose,
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| * including commercial applications, and to alter it and redistribute it
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| * freely, subject to the following restrictions:
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| * 1. The origin of this software must not be misrepresented; you must not
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| * claim that you wrote the original software. If you use this software
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| * in a product, an acknowledgment in the product documentation would be
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| * appreciated but is not required.
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| * 2. Altered source versions must be plainly marked as such, and must not be
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| * misrepresented as being the original software.
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| * 3. This notice may not be removed or altered from any source distribution.
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| */
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| 
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| #ifndef B2_GEAR_JOINT_H
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| #define B2_GEAR_JOINT_H
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| 
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| #include "Box2D/Dynamics/Joints/b2Joint.h"
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| 
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| /// Gear joint definition. This definition requires two existing
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| /// revolute or prismatic joints (any combination will work).
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| struct b2GearJointDef : public b2JointDef
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| {
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| 	b2GearJointDef()
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| 	{
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| 		type = e_gearJoint;
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| 		joint1 = nullptr;
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| 		joint2 = nullptr;
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| 		ratio = 1.0f;
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| 	}
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| 
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| 	/// The first revolute/prismatic joint attached to the gear joint.
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| 	b2Joint* joint1;
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| 
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| 	/// The second revolute/prismatic joint attached to the gear joint.
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| 	b2Joint* joint2;
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| 
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| 	/// The gear ratio.
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| 	/// @see b2GearJoint for explanation.
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| 	float32 ratio;
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| };
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| 
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| /// A gear joint is used to connect two joints together. Either joint
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| /// can be a revolute or prismatic joint. You specify a gear ratio
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| /// to bind the motions together:
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| /// coordinate1 + ratio * coordinate2 = constant
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| /// The ratio can be negative or positive. If one joint is a revolute joint
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| /// and the other joint is a prismatic joint, then the ratio will have units
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| /// of length or units of 1/length.
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| /// @warning You have to manually destroy the gear joint if joint1 or joint2
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| /// is destroyed.
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| class b2GearJoint : public b2Joint
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| {
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| public:
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| 	b2Vec2 GetAnchorA() const override;
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| 	b2Vec2 GetAnchorB() const override;
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| 
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| 	b2Vec2 GetReactionForce(float32 inv_dt) const override;
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| 	float32 GetReactionTorque(float32 inv_dt) const override;
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| 
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| 	/// Get the first joint.
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| 	b2Joint* GetJoint1() { return m_joint1; }
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| 
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| 	/// Get the second joint.
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| 	b2Joint* GetJoint2() { return m_joint2; }
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| 
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| 	/// Set/Get the gear ratio.
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| 	void SetRatio(float32 ratio);
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| 	float32 GetRatio() const;
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| 
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| 	/// Dump joint to dmLog
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| 	void Dump() override;
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| 
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| protected:
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| 
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| 	friend class b2Joint;
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| 	b2GearJoint(const b2GearJointDef* data);
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| 
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| 	void InitVelocityConstraints(const b2SolverData& data) override;
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| 	void SolveVelocityConstraints(const b2SolverData& data) override;
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| 	bool SolvePositionConstraints(const b2SolverData& data) override;
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| 
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| 	b2Joint* m_joint1;
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| 	b2Joint* m_joint2;
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| 
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| 	b2JointType m_typeA;
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| 	b2JointType m_typeB;
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| 
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| 	// Body A is connected to body C
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| 	// Body B is connected to body D
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| 	b2Body* m_bodyC;
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| 	b2Body* m_bodyD;
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| 
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| 	// Solver shared
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| 	b2Vec2 m_localAnchorA;
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| 	b2Vec2 m_localAnchorB;
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| 	b2Vec2 m_localAnchorC;
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| 	b2Vec2 m_localAnchorD;
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| 
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| 	b2Vec2 m_localAxisC;
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| 	b2Vec2 m_localAxisD;
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| 
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| 	float32 m_referenceAngleA;
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| 	float32 m_referenceAngleB;
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| 
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| 	float32 m_constant;
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| 	float32 m_ratio;
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| 
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| 	float32 m_impulse;
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| 
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| 	// Solver temp
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| 	int32 m_indexA, m_indexB, m_indexC, m_indexD;
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| 	b2Vec2 m_lcA, m_lcB, m_lcC, m_lcD;
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| 	float32 m_mA, m_mB, m_mC, m_mD;
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| 	float32 m_iA, m_iB, m_iC, m_iD;
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| 	b2Vec2 m_JvAC, m_JvBD;
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| 	float32 m_JwA, m_JwB, m_JwC, m_JwD;
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| 	float32 m_mass;
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| };
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| 
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| #endif
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