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 /*
 * Copyright (c) 2006-2009 Erin Catto http://www.gphysics.com
 *
 * 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_WELD_JOINT_H
 #define B2_WELD_JOINT_H
 
 #include <Box2D/Dynamics/Joints/b2Joint.h>
 
 /// Weld joint definition. You need to specify local anchor points
 /// where they are attached and the relative body angle. The position
 /// of the anchor points is important for computing the reaction torque.
 struct b2WeldJointDef : public b2JointDef
 {
     b2WeldJointDef()
     {
         type = e_weldJoint;
         localAnchorA.Set(0.0f, 0.0f);
         localAnchorB.Set(0.0f, 0.0f);
         referenceAngle = 0.0f;
     }
 
     /// Initialize the bodies, anchors, and reference angle using a world
     /// anchor point.
     void Initialize(b2Body* body1, b2Body* body2, const b2Vec2& anchor);
 
     /// The local anchor point relative to body1's origin.
     b2Vec2 localAnchorA;
 
     /// The local anchor point relative to body2's origin.
     b2Vec2 localAnchorB;
 
     /// The body2 angle minus body1 angle in the reference state (radians).
     qreal referenceAngle;
 };
 
 /// A weld joint essentially glues two bodies together. A weld joint may
 /// distort somewhat because the island constraint solver is approximate.
 class b2WeldJoint : public b2Joint
 {
 public:
     b2Vec2 GetAnchorA() const override;
     b2Vec2 GetAnchorB() const override;
 
     b2Vec2 GetReactionForce(qreal inv_dt) const override;
     qreal GetReactionTorque(qreal inv_dt) const override;
 
 protected:
 
     friend class b2Joint;
 
     b2WeldJoint(const b2WeldJointDef* def);
 
     void InitVelocityConstraints(const b2TimeStep& step) override;
     void SolveVelocityConstraints(const b2TimeStep& step) override;
 
     bool SolvePositionConstraints(qreal baumgarte) override;
 
     b2Vec2 m_localAnchorA;
     b2Vec2 m_localAnchorB;
     qreal m_referenceAngle;
 
     b2Vec3 m_impulse;
 
     b2Mat33 m_mass;
 };
 
 #endif