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/******************************************************************************
* SOFA, Simulation Open-Framework Architecture, version 1.0 beta 4 *
* (c) 2006-2009 MGH, INRIA, USTL, UJF, CNRS *
* *
* This library is free software; you can redistribute it and/or modify it *
* under the terms of the GNU Lesser General Public License as published by *
* the Free Software Foundation; either version 2.1 of the License, or (at *
* your option) any later version. *
* *
* This library 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 Lesser General Public License *
* for more details. *
* *
* You should have received a copy of the GNU Lesser General Public License *
* along with this library; if not, write to the Free Software Foundation, *
* Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. *
*******************************************************************************
* SOFA :: Framework *
* *
* Authors: M. Adam, J. Allard, B. Andre, P-J. Bensoussan, S. Cotin, C. Duriez,*
* H. Delingette, F. Falipou, F. Faure, S. Fonteneau, L. Heigeas, C. Mendoza, *
* M. Nesme, P. Neumann, J-P. de la Plata Alcade, F. Poyer and F. Roy *
* *
* Contact information: contact@sofa-framework.org *
******************************************************************************/
/*
* (c) Copyright 1993, 1994, Silicon Graphics, Inc.
* ALL RIGHTS RESERVED
* Permission to use, copy, modify, and distribute this software for
* any purpose and without fee is hereby granted, provided that the above
* copyright notice appear in all copies and that both the copyright notice
* and this permission notice appear in supporting documentation, and that
* the name of Silicon Graphics, Inc. not be used in advertising
* or publicity pertaining to distribution of the software without specific,
* written prior permission.
*
* THE MATERIAL EMBODIED ON THIS SOFTWARE IS PROVIDED TO YOU "AS-IS"
* AND WITHOUT WARRANTY OF ANY KIND, EXPRESS, IMPLIED OR OTHERWISE,
* INCLUDING WITHOUT LIMITATION, ANY WARRANTY OF MERCHANTABILITY OR
* FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL SILICON
* GRAPHICS, INC. BE LIABLE TO YOU OR ANYONE ELSE FOR ANY DIRECT,
* SPECIAL, INCIDENTAL, INDIRECT OR CONSEQUENTIAL DAMAGES OF ANY
* KIND, OR ANY DAMAGES WHATSOEVER, INCLUDING WITHOUT LIMITATION,
* LOSS OF PROFIT, LOSS OF USE, SAVINGS OR REVENUE, OR THE CLAIMS OF
* THIRD PARTIES, WHETHER OR NOT SILICON GRAPHICS, INC. HAS BEEN
* ADVISED OF THE POSSIBILITY OF SUCH LOSS, HOWEVER CAUSED AND ON
* ANY THEORY OF LIABILITY, ARISING OUT OF OR IN CONNECTION WITH THE
* POSSESSION, USE OR PERFORMANCE OF THIS SOFTWARE.
*
* US Government Users Restricted Rights
* Use, duplication, or disclosure by the Government is subject to
* restrictions set forth in FAR 52.227.19(c)(2) or subparagraph
* (c)(1)(ii) of the Rights in Technical Data and Computer Software
* clause at DFARS 252.227-7013 and/or in similar or successor
* clauses in the FAR or the DOD or NASA FAR Supplement.
* Unpublished-- rights reserved under the copyright laws of the
* United States. Contractor/manufacturer is Silicon Graphics,
* Inc., 2011 N. Shoreline Blvd., Mountain View, CA 94039-7311.
*
* OpenGL(TM) is a trademark of Silicon Graphics, Inc.
*/
/*
* Trackball code:
*
* Implementation of a virtual trackball.
* Implemented by Gavin Bell, lots of ideas from Thant Tessman and
* the August '88 issue of Siggraph's "Computer Graphics," pp. 121-129.
*
* Modified by:
* Stephane Cotin
* Mitsubish Electric America
* June 1998
*/
#include <sofa/helper/gl/Trackball.h>
#include <math.h>
namespace sofa
{
namespace helper
{
namespace gl
{
using namespace sofa::defaulttype;
/*
* This size should really be based on the distance from the center of
* rotation to the point on the object underneath the mouse. That
* point would then track the mouse as closely as possible. This is a
* simple example, though, so that is left as an Exercise for the
* Programmer.
*/
#define TRACKBALLSIZE (0.8)
static double tb_project_to_sphere(double, double, double);
// Constructor
Trackball::Trackball()
{
_quat[0] = 0.0;
_quat[1] = 0.0;
_quat[2] = 0.0;
_quat[3] = 0.0;
}
// Destructor
Trackball::~Trackball()
{
}
Quaternion Trackball::GetQuaternion(void)
{
Quaternion Q;
Q[0] = _quat[0];
Q[1] = _quat[1];
Q[2] = _quat[2];
Q[3] = _quat[3];
return Q;
}
void Trackball::SetQuaternion(Quaternion Q)
{
_quat[0] = Q[0];
_quat[1] = Q[1];
_quat[2] = Q[2];
_quat[3] = Q[3];
}
/*
* Ok, simulate a track-ball. Project the points onto the virtual
* trackball, then figure out the axis of rotation, which is the cross
* product of P1 P2 and O P1 (O is the center of the ball, 0,0,0)
* Note: This is a deformed trackball-- is a trackball in the center,
* but is deformed into a hyperbolic sheet of rotation away from the
* center. This particular function was chosen after trying out
* several variations.
*
* It is assumed that the arguments to this routine are in the range
* (-1.0 ... 1.0)
*/
void Trackball::ComputeQuaternion(double p1x, double p1y, double p2x,
double p2y)
{
double phi; /* how much to rotate about axis */
double t;
if (p1x == p2x && p1y == p2y)
{
/* Zero rotation */
_quat[0] = _quat[1] = _quat[2] = 0.0;
_quat[3] = 1.0;
return;
}
// First, figure out z-coordinates for projection of P1 and P2 to deformed sphere
Vector3 p1 ((SReal)p1x, (SReal)p1y, (SReal)tb_project_to_sphere(TRACKBALLSIZE, p1x, p1y));
Vector3 p2 ((SReal)p2x, (SReal)p2y, (SReal)tb_project_to_sphere(TRACKBALLSIZE, p2x, p2y));
// Now, we want the cross product of P1 and P2
Vector3 a = cross(p2,p1);
// Figure out how much to rotate around that axis.
Vector3 d = p1 - p2;
t = d.norm() / (2.0 * TRACKBALLSIZE);
// Avoid problems with out-of-control values...
if (t > 1.0)
{
t = 1.0;
}
if (t < -1.0)
{
t = -1.0;
}
phi = 2.0 * asin(t);
_quat.axisToQuat(a, (SReal)phi);
}
// Project an x,y pair onto a sphere of radius r OR a hyperbolic sheet
// if we are away from the center of the sphere.
static double tb_project_to_sphere(double r, double x, double y)
{
double d, t, z;
d = sqrt(x * x + y * y);
if (d < r * 0.70710678118654752440)
{
/* Inside sphere */
z = sqrt(r * r - d * d);
}
else
{
/* On hyperbola */
t = r / 1.41421356237309504880;
z = t * t / d;
}
return z;
}
} // namespace gl
} // namespace helper
} // namespace sofa
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