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/* $Id: project.c,v 1.1 2003-02-28 11:42:07 pj Exp $ */

/*

 * Mesa 3-D graphics library

 * Version:  3.3

 * Copyright (C) 1995-2000  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 PC_HEADER

#include "all.h"

#else

#include <stdio.h>

#include <string.h>

#include <math.h>

#include "gluP.h"

#endif

/*

 * This code was contributed by Marc Buffat (buffat@mecaflu.ec-lyon.fr).

 * Thanks Marc!!!

 */

/* implementation de gluProject et gluUnproject */

/* M. Buffat 17/2/95 */

/*

 * Transform a point (column vector) by a 4x4 matrix.  I.e.  out = m * in

 * Input:  m - the 4x4 matrix

 *         in - the 4x1 vector

 * Output:  out - the resulting 4x1 vector.

 */

static void

transform_point(GLdouble out[4], const GLdouble m[16], const GLdouble in[4])

{

#define M(row,col)  m[col*4+row]

   out[0] =

      M(0, 0) * in[0] + M(0, 1) * in[1] + M(0, 2) * in[2] + M(0, 3) * in[3];

   out[1] =

      M(1, 0) * in[0] + M(1, 1) * in[1] + M(1, 2) * in[2] + M(1, 3) * in[3];

   out[2] =

      M(2, 0) * in[0] + M(2, 1) * in[1] + M(2, 2) * in[2] + M(2, 3) * in[3];

   out[3] =

      M(3, 0) * in[0] + M(3, 1) * in[1] + M(3, 2) * in[2] + M(3, 3) * in[3];

#undef M

}

/*

 * Perform a 4x4 matrix multiplication  (product = a x b).

 * Input:  a, b - matrices to multiply

 * Output:  product - product of a and b

 */

static void

matmul(GLdouble * product, const GLdouble * a, const GLdouble * b)

{

   /* This matmul was contributed by Thomas Malik */

   GLdouble temp[16];

   GLint i;

#define A(row,col)  a[(col<<2)+row]

#define B(row,col)  b[(col<<2)+row]

#define T(row,col)  temp[(col<<2)+row]

   /* i-te Zeile */

   for (i = 0; i < 4; i++) {

      T(i, 0) =

         A(i, 0) * B(0, 0) + A(i, 1) * B(1, 0) + A(i, 2) * B(2, 0) + A(i,

                                                                       3) *

         B(3, 0);

      T(i, 1) =

         A(i, 0) * B(0, 1) + A(i, 1) * B(1, 1) + A(i, 2) * B(2, 1) + A(i,

                                                                       3) *

         B(3, 1);

      T(i, 2) =

         A(i, 0) * B(0, 2) + A(i, 1) * B(1, 2) + A(i, 2) * B(2, 2) + A(i,

                                                                       3) *

         B(3, 2);

      T(i, 3) =

         A(i, 0) * B(0, 3) + A(i, 1) * B(1, 3) + A(i, 2) * B(2, 3) + A(i,

                                                                       3) *

         B(3, 3);

   }

#undef A

#undef B

#undef T

   MEMCPY(product, temp, 16 * sizeof(GLdouble));

}

/*

 * Compute inverse of 4x4 transformation matrix.

 * Code contributed by Jacques Leroy jle@star.be

 * Return GL_TRUE for success, GL_FALSE for failure (singular matrix)

 */

static GLboolean

invert_matrix(const GLdouble * m, GLdouble * out)

{

/* NB. OpenGL Matrices are COLUMN major. */

#define SWAP_ROWS(a, b) { GLdouble *_tmp = a; (a)=(b); (b)=_tmp; }

#define MAT(m,r,c) (m)[(c)*4+(r)]

   GLdouble wtmp[4][8];

   GLdouble m0, m1, m2, m3, s;

   GLdouble *r0, *r1, *r2, *r3;

   r0 = wtmp[0], r1 = wtmp[1], r2 = wtmp[2], r3 = wtmp[3];

   r0[0] = MAT(m, 0, 0), r0[1] = MAT(m, 0, 1),

      r0[2] = MAT(m, 0, 2), r0[3] = MAT(m, 0, 3),

      r0[4] = 1.0, r0[5] = r0[6] = r0[7] = 0.0,

      r1[0] = MAT(m, 1, 0), r1[1] = MAT(m, 1, 1),

      r1[2] = MAT(m, 1, 2), r1[3] = MAT(m, 1, 3),

      r1[5] = 1.0, r1[4] = r1[6] = r1[7] = 0.0,

      r2[0] = MAT(m, 2, 0), r2[1] = MAT(m, 2, 1),

      r2[2] = MAT(m, 2, 2), r2[3] = MAT(m, 2, 3),

      r2[6] = 1.0, r2[4] = r2[5] = r2[7] = 0.0,

      r3[0] = MAT(m, 3, 0), r3[1] = MAT(m, 3, 1),

      r3[2] = MAT(m, 3, 2), r3[3] = MAT(m, 3, 3),

      r3[7] = 1.0, r3[4] = r3[5] = r3[6] = 0.0;

   /* choose pivot - or die */

   if (fabs(r3[0]) > fabs(r2[0]))

      SWAP_ROWS(r3, r2);

   if (fabs(r2[0]) > fabs(r1[0]))

      SWAP_ROWS(r2, r1);

   if (fabs(r1[0]) > fabs(r0[0]))

      SWAP_ROWS(r1, r0);

   if (0.0 == r0[0])

      return GL_FALSE;

   /* eliminate first variable     */

   m1 = r1[0] / r0[0];

   m2 = r2[0] / r0[0];

   m3 = r3[0] / r0[0];

   s = r0[1];

   r1[1] -= m1 * s;

   r2[1] -= m2 * s;

   r3[1] -= m3 * s;

   s = r0[2];

   r1[2] -= m1 * s;

   r2[2] -= m2 * s;

   r3[2] -= m3 * s;

   s = r0[3];

   r1[3] -= m1 * s;

   r2[3] -= m2 * s;

   r3[3] -= m3 * s;

   s = r0[4];

   if (s != 0.0) {

      r1[4] -= m1 * s;

      r2[4] -= m2 * s;

      r3[4] -= m3 * s;

   }

   s = r0[5];

   if (s != 0.0) {

      r1[5] -= m1 * s;

      r2[5] -= m2 * s;

      r3[5] -= m3 * s;

   }

   s = r0[6];

   if (s != 0.0) {

      r1[6] -= m1 * s;

      r2[6] -= m2 * s;

      r3[6] -= m3 * s;

   }

   s = r0[7];

   if (s != 0.0) {

      r1[7] -= m1 * s;

      r2[7] -= m2 * s;

      r3[7] -= m3 * s;

   }

   /* choose pivot - or die */

   if (fabs(r3[1]) > fabs(r2[1]))

      SWAP_ROWS(r3, r2);

   if (fabs(r2[1]) > fabs(r1[1]))

      SWAP_ROWS(r2, r1);

   if (0.0 == r1[1])

      return GL_FALSE;

   /* eliminate second variable */

   m2 = r2[1] / r1[1];

   m3 = r3[1] / r1[1];

   r2[2] -= m2 * r1[2];

   r3[2] -= m3 * r1[2];

   r2[3] -= m2 * r1[3];

   r3[3] -= m3 * r1[3];

   s = r1[4];

   if (0.0 != s) {

      r2[4] -= m2 * s;

      r3[4] -= m3 * s;

   }

   s = r1[5];

   if (0.0 != s) {

      r2[5] -= m2 * s;

      r3[5] -= m3 * s;

   }

   s = r1[6];

   if (0.0 != s) {

      r2[6] -= m2 * s;

      r3[6] -= m3 * s;

   }

   s = r1[7];

   if (0.0 != s) {

      r2[7] -= m2 * s;

      r3[7] -= m3 * s;

   }

   /* choose pivot - or die */

   if (fabs(r3[2]) > fabs(r2[2]))

      SWAP_ROWS(r3, r2);

   if (0.0 == r2[2])

      return GL_FALSE;

   /* eliminate third variable */

   m3 = r3[2] / r2[2];

   r3[3] -= m3 * r2[3], r3[4] -= m3 * r2[4],

      r3[5] -= m3 * r2[5], r3[6] -= m3 * r2[6], r3[7] -= m3 * r2[7];

   /* last check */

   if (0.0 == r3[3])

      return GL_FALSE;

   s = 1.0 / r3[3];             /* now back substitute row 3 */

   r3[4] *= s;

   r3[5] *= s;

   r3[6] *= s;

   r3[7] *= s;

   m2 = r2[3];                  /* now back substitute row 2 */

   s = 1.0 / r2[2];

   r2[4] = s * (r2[4] - r3[4] * m2), r2[5] = s * (r2[5] - r3[5] * m2),

      r2[6] = s * (r2[6] - r3[6] * m2), r2[7] = s * (r2[7] - r3[7] * m2);

   m1 = r1[3];

   r1[4] -= r3[4] * m1, r1[5] -= r3[5] * m1,

      r1[6] -= r3[6] * m1, r1[7] -= r3[7] * m1;

   m0 = r0[3];

   r0[4] -= r3[4] * m0, r0[5] -= r3[5] * m0,

      r0[6] -= r3[6] * m0, r0[7] -= r3[7] * m0;

   m1 = r1[2];                  /* now back substitute row 1 */

   s = 1.0 / r1[1];

   r1[4] = s * (r1[4] - r2[4] * m1), r1[5] = s * (r1[5] - r2[5] * m1),

      r1[6] = s * (r1[6] - r2[6] * m1), r1[7] = s * (r1[7] - r2[7] * m1);

   m0 = r0[2];

   r0[4] -= r2[4] * m0, r0[5] -= r2[5] * m0,

      r0[6] -= r2[6] * m0, r0[7] -= r2[7] * m0;

   m0 = r0[1];                  /* now back substitute row 0 */

   s = 1.0 / r0[0];

   r0[4] = s * (r0[4] - r1[4] * m0), r0[5] = s * (r0[5] - r1[5] * m0),

      r0[6] = s * (r0[6] - r1[6] * m0), r0[7] = s * (r0[7] - r1[7] * m0);

   MAT(out, 0, 0) = r0[4];

   MAT(out, 0, 1) = r0[5], MAT(out, 0, 2) = r0[6];

   MAT(out, 0, 3) = r0[7], MAT(out, 1, 0) = r1[4];

   MAT(out, 1, 1) = r1[5], MAT(out, 1, 2) = r1[6];

   MAT(out, 1, 3) = r1[7], MAT(out, 2, 0) = r2[4];

   MAT(out, 2, 1) = r2[5], MAT(out, 2, 2) = r2[6];

   MAT(out, 2, 3) = r2[7], MAT(out, 3, 0) = r3[4];

   MAT(out, 3, 1) = r3[5], MAT(out, 3, 2) = r3[6];

   MAT(out, 3, 3) = r3[7];

   return GL_TRUE;

#undef MAT

#undef SWAP_ROWS

}

/* projection du point (objx,objy,obz) sur l'ecran (winx,winy,winz) */

GLint GLAPIENTRY

gluProject(GLdouble objx, GLdouble objy, GLdouble objz,

           const GLdouble model[16], const GLdouble proj[16],

           const GLint viewport[4],

           GLdouble * winx, GLdouble * winy, GLdouble * winz)

{

   /* matrice de transformation */

   GLdouble in[4], out[4];

   /* initilise la matrice et le vecteur a transformer */

   in[0] = objx;

   in[1] = objy;

   in[2] = objz;

   in[3] = 1.0;

   transform_point(out, model, in);

   transform_point(in, proj, out);

   /* d'ou le resultat normalise entre -1 et 1 */

   if (in[3] == 0.0)

      return GL_FALSE;

   in[0] /= in[3];

   in[1] /= in[3];

   in[2] /= in[3];

   /* en coordonnees ecran */

   *winx = viewport[0] + (1 + in[0]) * viewport[2] / 2;

   *winy = viewport[1] + (1 + in[1]) * viewport[3] / 2;

   /* entre 0 et 1 suivant z */

   *winz = (1 + in[2]) / 2;

   return GL_TRUE;

}

/* transformation du point ecran (winx,winy,winz) en point objet */

GLint GLAPIENTRY

gluUnProject(GLdouble winx, GLdouble winy, GLdouble winz,

             const GLdouble model[16], const GLdouble proj[16],

             const GLint viewport[4],

             GLdouble * objx, GLdouble * objy, GLdouble * objz)

{

   /* matrice de transformation */

   GLdouble m[16], A[16];

   GLdouble in[4], out[4];

   /* transformation coordonnees normalisees entre -1 et 1 */

   in[0] = (winx - viewport[0]) * 2 / viewport[2] - 1.0;

   in[1] = (winy - viewport[1]) * 2 / viewport[3] - 1.0;

   in[2] = 2 * winz - 1.0;

   in[3] = 1.0;

   /* calcul transformation inverse */

   matmul(A, proj, model);

   invert_matrix(A, m);

   /* d'ou les coordonnees objets */

   transform_point(out, m, in);

   if (out[3] == 0.0)

      return GL_FALSE;

   *objx = out[0] / out[3];

   *objy = out[1] / out[3];

   *objz = out[2] / out[3];

   return GL_TRUE;

}

/*

 * New in GLU 1.3

 * This is like gluUnProject but also takes near and far DepthRange values.

 */

#ifdef GLU_VERSION_1_3

GLint GLAPIENTRY

gluUnProject4(GLdouble winx, GLdouble winy, GLdouble winz, GLdouble clipw,

              const GLdouble modelMatrix[16],

              const GLdouble projMatrix[16],

              const GLint viewport[4],

              GLclampd nearZ, GLclampd farZ,

              GLdouble * objx, GLdouble * objy, GLdouble * objz,

              GLdouble * objw)

{

   /* matrice de transformation */

   GLdouble m[16], A[16];

   GLdouble in[4], out[4];

   GLdouble z = nearZ + winz * (farZ - nearZ);

   /* transformation coordonnees normalisees entre -1 et 1 */

   in[0] = (winx - viewport[0]) * 2 / viewport[2] - 1.0;

   in[1] = (winy - viewport[1]) * 2 / viewport[3] - 1.0;

   in[2] = 2.0 * z - 1.0;

   in[3] = clipw;

   /* calcul transformation inverse */

   matmul(A, projMatrix, modelMatrix);

   invert_matrix(A, m);

   /* d'ou les coordonnees objets */

   transform_point(out, m, in);

   if (out[3] == 0.0)

      return GL_FALSE;

   *objx = out[0] / out[3];

   *objy = out[1] / out[3];

   *objz = out[2] / out[3];

   *objw = out[3];

   return GL_TRUE;

}

#endif