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/*
* frame.cc -- ePiX orthonormal basis
*
* This file is part of ePiX, a preprocessor for creating high-quality
* line figures in LaTeX
*
* Version 1.0.15
* Last Change: October 10, 2006
*/
/*
* Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006
* Andrew D. Hwang <rot 13 nujnat at zngupf dot ubylpebff dot rqh>
* Department of Mathematics and Computer Science
* College of the Holy Cross
* Worcester, MA, 01610-2395, USA
*/
/*
* ePiX 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.
*
* ePiX 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 ePiX; if not, write to the Free Software Foundation, Inc.,
* 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include "globals.h"
#include "functions.h"
#include "errors.h"
#include "triples.h"
#include "frame.h"
namespace ePiX {
// standard basis
frame::frame()
: m_e1(E_1), m_e2(E_2), m_e3(E_3) { }
// frame constructor, suitable for (sea,sky,eye) frames: Usually we
// know the eye vector and want to preserve its direction. The frame
// is guaranteed to be right-handed, and the first arg is immaterial.
frame::frame(P arg1, P arg2, P arg3)
{
if (norm(arg2*arg3) < EPIX_EPSILON) // too nearly linearly dependent
epix_error("Linearly dependent arguments to frame");
// partial Gram-Schmidt
arg3 *= 1/norm(arg3); // normalize eye
arg2 %= arg3; // orthogonalize sky_vector, preserving screen direction
arg2 *= 1/norm(arg2); // and normalize
m_e1 = arg2*arg3;
m_e2 = arg2;
m_e3 = arg3;
}
frame& frame::rot1(const double angle)
{
P temp2(m_e2);
P temp3(m_e3);
m_e2 = (Cos(angle)*(temp2)) - (Sin(angle)*(temp3));
m_e3 = (Sin(angle)*(temp2)) + (Cos(angle)*(temp3));
return *this;
}
frame& frame::rot2(const double angle)
{
P temp3(m_e3);
P temp1(m_e1);
m_e3 = (Cos(angle)*(temp3)) - (Sin(angle)*(temp1));
m_e1 = (Sin(angle)*(temp3)) + (Cos(angle)*(temp1));
return *this;
}
frame& frame::rot3(const double angle)
{
P temp1(m_e1);
P temp2(m_e2);
m_e1 = (Cos(angle)*(temp1)) - (Sin(angle)*(temp2));
m_e2 = (Sin(angle)*(temp1)) + (Cos(angle)*(temp2));
return *this;
}
// frame elements
P frame::sea() const
{
return m_e1;
}
P frame::sky() const
{
return m_e2;
}
P frame::eye() const
{
return m_e3;
}
} // end of namespace
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