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/*
* Copyright (C) 2002 Terence M. Welsh
* Ported to Linux by Tugrul Galatali <tugrul@galatali.com>
*
* Implicit is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* Implicit 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 this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include "impElement.h"
impElement::impElement ()
{
mat[0] = mat[5] = mat[10] = mat[15]
= invmat[0] = invmat[5] = invmat[10] = invmat[15] = 1.0f;
mat[1] = mat[2] = mat[3] = mat[4]
= mat[6] = mat[7] = mat[8] = mat[9]
= mat[11] = mat[12] = mat[13] = mat[14]
= invmat[1] = invmat[2] = invmat[3] = invmat[4]
= invmat[6] = invmat[7] = invmat[8] = invmat[9]
= invmat[11] = invmat[12] = invmat[13] = invmat[14] = 0.0f;
}
void
impElement::setPosition (float x, float y, float z)
{
mat[12] = x;
mat[13] = y;
mat[14] = z;
invmat[12] = -x;
invmat[13] = -y;
invmat[14] = -z;
}
void impElement::setPosition (float *position)
{
mat[12] = position[0];
mat[13] = position[1];
mat[14] = position[2];
invmat[12] = -position[0];
invmat[13] = -position[1];
invmat[14] = -position[2];
}
// Don't need to set this for simple spheres.
// A whole matrix is only necessary for weird asymmetric objects.
void impElement::setMatrix (float *m)
{
for (int i = 0; i < 16; i++)
mat[i] = m[i];
invertMatrix ();
}
void impElement::invertMatrix ()
{
float rmat[4][8];
float a, b;
int i, j, k;
// inititialize reduction matrix
rmat[0][0] = mat[0];
rmat[1][0] = mat[1];
rmat[2][0] = mat[2];
rmat[3][0] = mat[3];
rmat[0][1] = mat[4];
rmat[1][1] = mat[5];
rmat[2][1] = mat[6];
rmat[3][1] = mat[7];
rmat[0][2] = mat[8];
rmat[1][2] = mat[9];
rmat[2][2] = mat[10];
rmat[3][2] = mat[11];
rmat[0][3] = mat[12];
rmat[1][3] = mat[13];
rmat[2][3] = mat[14];
rmat[3][3] = mat[15];
rmat[0][4] = 1.0f;
rmat[1][4] = 0.0f;
rmat[2][4] = 0.0f;
rmat[3][4] = 0.0f;
rmat[0][5] = 0.0f;
rmat[1][5] = 1.0f;
rmat[2][5] = 0.0f;
rmat[3][5] = 0.0f;
rmat[0][6] = 0.0f;
rmat[1][6] = 0.0f;
rmat[2][6] = 1.0f;
rmat[3][6] = 0.0f;
rmat[0][7] = 0.0f;
rmat[1][7] = 0.0f;
rmat[2][7] = 0.0f;
rmat[3][7] = 1.0f;
// perform reductions
for (i = 0; i < 4; i++) {
a = rmat[i][i];
if (a == 0.0f)
return; // matrix is singular, can't be inverted
a = 1.0f / a;
for (j = 0; j < 8; j++)
rmat[i][j] = rmat[i][j] * a;
for (k = 0; k < 4; k++) {
if ((k - i) != 0) {
b = rmat[k][i];
for (j = 0; j < 8; j++)
rmat[k][j] = rmat[k][j] - b * rmat[i][j];
}
}
}
// extract inverted matrix
invmat[0] = rmat[0][4];
invmat[1] = rmat[1][4];
invmat[2] = rmat[2][4];
invmat[3] = rmat[3][4];
invmat[4] = rmat[0][5];
invmat[5] = rmat[1][5];
invmat[6] = rmat[2][5];
invmat[7] = rmat[3][5];
invmat[8] = rmat[0][6];
invmat[9] = rmat[1][6];
invmat[10] = rmat[2][6];
invmat[11] = rmat[3][6];
invmat[12] = rmat[0][7];
invmat[13] = rmat[1][7];
invmat[14] = rmat[2][7];
invmat[15] = rmat[3][7];
}
float impElement::value (float *position)
{
return (0.0f);
}
void impElement::center (float *position)
{
position[0] = mat[12];
position[1] = mat[13];
position[2] = mat[14];
}
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