source: code/branches/mergeFS18/src/external/bullet/BulletDynamics/ConstraintSolver/btUniversalConstraint.h

/*
Bullet Continuous Collision Detection and Physics Library, http://bulletphysics.org
Copyright (C) 2006, 2007 Sony Computer Entertainment Inc. 

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 BT_UNIVERSAL_CONSTRAINT_H
#define BT_UNIVERSAL_CONSTRAINT_H



#include "LinearMath/btVector3.h"
#include "btTypedConstraint.h"
#include "btGeneric6DofConstraint.h"



/// Constraint similar to ODE Universal Joint
/// has 2 rotatioonal degrees of freedom, similar to Euler rotations around Z (axis 1)
/// and Y (axis 2)
/// Description from ODE manual : 
/// "Given axis 1 on body 1, and axis 2 on body 2 that is perpendicular to axis 1, it keeps them perpendicular. 
/// In other words, rotation of the two bodies about the direction perpendicular to the two axes will be equal."

class btUniversalConstraint : public btGeneric6DofConstraint
{
protected:
        btVector3       m_anchor;
        btVector3       m_axis1;
        btVector3       m_axis2;
public:
        // constructor
        // anchor, axis1 and axis2 are in world coordinate system
        // axis1 must be orthogonal to axis2
    btUniversalConstraint(btRigidBody& rbA, btRigidBody& rbB, btVector3& anchor, btVector3& axis1, btVector3& axis2);
        // access
        const btVector3& getAnchor() { return m_calculatedTransformA.getOrigin(); }
        const btVector3& getAnchor2() { return m_calculatedTransformB.getOrigin(); }
        const btVector3& getAxis1() { return m_axis1; }
        const btVector3& getAxis2() { return m_axis2; }
        btScalar getAngle1() { return getAngle(2); }
        btScalar getAngle2() { return getAngle(1); }
        // limits
        void setUpperLimit(btScalar ang1max, btScalar ang2max) { setAngularUpperLimit(btVector3(0.f, ang1max, ang2max)); }
        void setLowerLimit(btScalar ang1min, btScalar ang2min) { setAngularLowerLimit(btVector3(0.f, ang1min, ang2min)); }

        void setAxis( const btVector3& axis1, const btVector3& axis2);
};



#endif // BT_UNIVERSAL_CONSTRAINT_H