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/***************************************************************************
sq_glu.cpp - description
-------------------
begin : ??? ??? 29 2004
copyright : (C) 2004 by Baryshev Dmitry
email : ksquirrel.iv@gmail.com
***************************************************************************/
/*
* Mesa 3-D graphics library
* Version: 3.5
* Copyright (C) 1995-2001 Brian Paul
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License as published by the Free Software Foundation; either
* version 2 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
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public
* License along with this library; if not, write to the Free
* Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include "sq_glu.h"
#include <cmath>
/*
* Replacement for gluLookAt().
*/
void SQ_GLU::gluLookAt(GLdouble eyex, GLdouble eyey, GLdouble eyez, GLdouble centerx, GLdouble centery, GLdouble centerz, GLdouble upx, GLdouble upy, GLdouble upz)
{
GLdouble m[16];
GLdouble x[3], y[3], z[3];
GLdouble mag;
z[0] = eyex - centerx;
z[1] = eyey - centery;
z[2] = eyez - centerz;
mag = sqrt(z[0] * z[0] + z[1] * z[1] + z[2] * z[2]);
if(mag)
{
z[0] /= mag;
z[1] /= mag;
z[2] /= mag;
}
y[0] = upx;
y[1] = upy;
y[2] = upz;
x[0] = y[1] * z[2] - y[2] * z[1];
x[1] = -y[0] * z[2] + y[2] * z[0];
x[2] = y[0] * z[1] - y[1] * z[0];
y[0] = z[1] * x[2] - z[2] * x[1];
y[1] = -z[0] * x[2] + z[2] * x[0];
y[2] = z[0] * x[1] - z[1] * x[0];
mag = sqrt(x[0] * x[0] + x[1] * x[1] + x[2] * x[2]);
if(mag)
{
x[0] /= mag;
x[1] /= mag;
x[2] /= mag;
}
mag = sqrt(y[0] * y[0] + y[1] * y[1] + y[2] * y[2]);
if(mag)
{
y[0] /= mag;
y[1] /= mag;
y[2] /= mag;
}
#define M(row,col) m[col*4+row]
M(0, 0) = x[0];
M(0, 1) = x[1];
M(0, 2) = x[2];
M(0, 3) = 0.0;
M(1, 0) = y[0];
M(1, 1) = y[1];
M(1, 2) = y[2];
M(1, 3) = 0.0;
M(2, 0) = z[0];
M(2, 1) = z[1];
M(2, 2) = z[2];
M(2, 3) = 0.0;
M(3, 0) = 0.0;
M(3, 1) = 0.0;
M(3, 2) = 0.0;
M(3, 3) = 1.0;
#undef M
glMultMatrixd(m);
glTranslated(-eyex, -eyey, -eyez);
}
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