/* The original version of this file came from OpenTissue
 *
 * Copyright (C) 2003 Department of Computer Science, University of Copenhagen
 * Modifications copyright 2004, 2005 Nicholas Bishop
 * 
 * This file is part of SharpConstruct.
 *
 * SharpConstruct is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * SharpConstruct is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with SharpConstruct; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA */

#ifndef ARCBALL_H
#define ARCBALL_H

class ArcBall 
{
public:
	typedef double Vector[ 3 ];
	typedef double Transform[ 4 ][ 4 ];

	ArcBall( const double radius );
	~ArcBall();

	static void NormalizeCoordinates( double&, double&, int, int );
	
	void Reset();
	
	void BeginDrag( const double, const double );
	void Drag( const double, const double );
	
	const Transform& Transformation();

	const Transform& SnapRotation( const Transform& t, float angle );
	void BakeSnapRotation();
protected:
	double radius;
	
	Vector Panchor;
	Vector Pcurrent;
	
	double CurrentAngle;
	Vector CurrentAxis;
	
	Transform AnchorTransformation;
	Transform IncrementalTransformation;
	Transform CurrentTransformation;
	Transform SnapTransform;
	
	// Operations on type Transform
	void Identity( Transform& ) const;
	void Copy( const Transform&, Transform& ) const;
	void Multiply( const Transform&, const Transform&, Transform& ) const;
	
	// Operations on type Vector
	double Length( const Vector& ) const;
	void Copy( const Vector&, Vector& ) const;
	double Dot( const Vector&, const Vector& ) const;
	void Cross( const Vector&, const Vector&, Vector& ) const;
private:
	void ProjectOntoSurface( Vector& );
	void ComputeIncrementalTransformation( const Vector&, const Vector&,
	                                       Transform& );
};

#endif // ARCBALL_H