src/glu/mini/project.c

   1 /* $Id: project.c,v 1.2 2003/08/22 20:11:43 brianp Exp $ */
   2
   3 /*
   4  * Mesa 3-D graphics library
   5  * Version:  3.3
   6  * Copyright (C) 1995-2000  Brian Paul
   7  *
   8  * This library is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU Library General Public
  10  * License as published by the Free Software Foundation; either
  11  * version 2 of the License, or (at your option) any later version.
  12  *
  13  * This library is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  16  * Library General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU Library General Public
  19  * License along with this library; if not, write to the Free
  20  * Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  21  */
  22
  23
  24 #ifdef PC_HEADER
  25 #include "all.h"
  26 #else
  27 #include <stdio.h>
  28 #include <string.h>
  29 #include <math.h>
  30 #include "gluP.h"
  31 #endif
  32
  33
  34 /*
  35  * This code was contributed by Marc Buffat (buffat@mecaflu.ec-lyon.fr).
  36  * Thanks Marc!!!
  37  */
  38
  39
  40
  41 /* implementation de gluProject et gluUnproject */
  42 /* M. Buffat 17/2/95 */
  43
  44
  45
  46 /*
  47  * Transform a point (column vector) by a 4x4 matrix.  I.e.  out = m * in
  48  * Input:  m - the 4x4 matrix
  49  *         in - the 4x1 vector
  50  * Output:  out - the resulting 4x1 vector.
  51  */
  52 static void
  53 transform_point(GLdouble out[4], const GLdouble m[16], const GLdouble in[4])
  54 {
  55 #define M(row,col)  m[col*4+row]
  56    out[0] =
  57       M(0, 0) * in[0] + M(0, 1) * in[1] + M(0, 2) * in[2] + M(0, 3) * in[3];
  58    out[1] =
  59       M(1, 0) * in[0] + M(1, 1) * in[1] + M(1, 2) * in[2] + M(1, 3) * in[3];
  60    out[2] =
  61       M(2, 0) * in[0] + M(2, 1) * in[1] + M(2, 2) * in[2] + M(2, 3) * in[3];
  62    out[3] =
  63       M(3, 0) * in[0] + M(3, 1) * in[1] + M(3, 2) * in[2] + M(3, 3) * in[3];
  64 #undef M
  65 }
  66
  67
  68
  69
  70 /*
  71  * Perform a 4x4 matrix multiplication  (product = a x b).
  72  * Input:  a, b - matrices to multiply
  73  * Output:  product - product of a and b
  74  */
  75 static void
  76 matmul(GLdouble * product, const GLdouble * a, const GLdouble * b)
  77 {
  78    /* This matmul was contributed by Thomas Malik */
  79    GLdouble temp[16];
  80    GLint i;
  81
  82 #define A(row,col)  a[(col<<2)+row]
  83 #define B(row,col)  b[(col<<2)+row]
  84 #define T(row,col)  temp[(col<<2)+row]
  85
  86    /* i-te Zeile */
  87    for (i = 0; i < 4; i++) {
  88       T(i, 0) =
  89          A(i, 0) * B(0, 0) + A(i, 1) * B(1, 0) + A(i, 2) * B(2, 0) + A(i,
  90                                                                        3) *
  91          B(3, 0);
  92       T(i, 1) =
  93          A(i, 0) * B(0, 1) + A(i, 1) * B(1, 1) + A(i, 2) * B(2, 1) + A(i,
  94                                                                        3) *
  95          B(3, 1);
  96       T(i, 2) =
  97          A(i, 0) * B(0, 2) + A(i, 1) * B(1, 2) + A(i, 2) * B(2, 2) + A(i,
  98                                                                        3) *
  99          B(3, 2);
 100       T(i, 3) =
 101          A(i, 0) * B(0, 3) + A(i, 1) * B(1, 3) + A(i, 2) * B(2, 3) + A(i,
 102                                                                        3) *
 103          B(3, 3);
 104    }
 105
 106 #undef A
 107 #undef B
 108 #undef T
 109    MEMCPY(product, temp, 16 * sizeof(GLdouble));
 110 }
 111
 112
 113
 114 /*
 115  * Compute inverse of 4x4 transformation matrix.
 116  * Code contributed by Jacques Leroy jle@star.be
 117  * Return GL_TRUE for success, GL_FALSE for failure (singular matrix)
 118  */
 119 static GLboolean
 120 invert_matrix(const GLdouble * m, GLdouble * out)
 121 {
 122 /* NB. OpenGL Matrices are COLUMN major. */
 123 #define SWAP_ROWS(a, b) { GLdouble *_tmp = a; (a)=(b); (b)=_tmp; }
 124 #define MAT(m,r,c) (m)[(c)*4+(r)]
 125
 126    GLdouble wtmp[4][8];
 127    GLdouble m0, m1, m2, m3, s;
 128    GLdouble *r0, *r1, *r2, *r3;
 129
 130    r0 = wtmp[0], r1 = wtmp[1], r2 = wtmp[2], r3 = wtmp[3];
 131
 132    r0[0] = MAT(m, 0, 0), r0[1] = MAT(m, 0, 1),
 133       r0[2] = MAT(m, 0, 2), r0[3] = MAT(m, 0, 3),
 134       r0[4] = 1.0, r0[5] = r0[6] = r0[7] = 0.0,
 135       r1[0] = MAT(m, 1, 0), r1[1] = MAT(m, 1, 1),
 136       r1[2] = MAT(m, 1, 2), r1[3] = MAT(m, 1, 3),
 137       r1[5] = 1.0, r1[4] = r1[6] = r1[7] = 0.0,
 138       r2[0] = MAT(m, 2, 0), r2[1] = MAT(m, 2, 1),
 139       r2[2] = MAT(m, 2, 2), r2[3] = MAT(m, 2, 3),
 140       r2[6] = 1.0, r2[4] = r2[5] = r2[7] = 0.0,
 141       r3[0] = MAT(m, 3, 0), r3[1] = MAT(m, 3, 1),
 142       r3[2] = MAT(m, 3, 2), r3[3] = MAT(m, 3, 3),
 143       r3[7] = 1.0, r3[4] = r3[5] = r3[6] = 0.0;
 144
 145    /* choose pivot - or die */
 146    if (fabs(r3[0]) > fabs(r2[0]))
 147       SWAP_ROWS(r3, r2);
 148    if (fabs(r2[0]) > fabs(r1[0]))
 149       SWAP_ROWS(r2, r1);
 150    if (fabs(r1[0]) > fabs(r0[0]))
 151       SWAP_ROWS(r1, r0);
 152    if (0.0 == r0[0])
 153       return GL_FALSE;
 154
 155    /* eliminate first variable     */
 156    m1 = r1[0] / r0[0];
 157    m2 = r2[0] / r0[0];
 158    m3 = r3[0] / r0[0];
 159    s = r0[1];
 160    r1[1] -= m1 * s;
 161    r2[1] -= m2 * s;
 162    r3[1] -= m3 * s;
 163    s = r0[2];
 164    r1[2] -= m1 * s;
 165    r2[2] -= m2 * s;
 166    r3[2] -= m3 * s;
 167    s = r0[3];
 168    r1[3] -= m1 * s;
 169    r2[3] -= m2 * s;
 170    r3[3] -= m3 * s;
 171    s = r0[4];
 172    if (s != 0.0) {
 173       r1[4] -= m1 * s;
 174       r2[4] -= m2 * s;
 175       r3[4] -= m3 * s;
 176    }
 177    s = r0[5];
 178    if (s != 0.0) {
 179       r1[5] -= m1 * s;
 180       r2[5] -= m2 * s;
 181       r3[5] -= m3 * s;
 182    }
 183    s = r0[6];
 184    if (s != 0.0) {
 185       r1[6] -= m1 * s;
 186       r2[6] -= m2 * s;
 187       r3[6] -= m3 * s;
 188    }
 189    s = r0[7];
 190    if (s != 0.0) {
 191       r1[7] -= m1 * s;
 192       r2[7] -= m2 * s;
 193       r3[7] -= m3 * s;
 194    }
 195
 196    /* choose pivot - or die */
 197    if (fabs(r3[1]) > fabs(r2[1]))
 198       SWAP_ROWS(r3, r2);
 199    if (fabs(r2[1]) > fabs(r1[1]))
 200       SWAP_ROWS(r2, r1);
 201    if (0.0 == r1[1])
 202       return GL_FALSE;
 203
 204    /* eliminate second variable */
 205    m2 = r2[1] / r1[1];
 206    m3 = r3[1] / r1[1];
 207    r2[2] -= m2 * r1[2];
 208    r3[2] -= m3 * r1[2];
 209    r2[3] -= m2 * r1[3];
 210    r3[3] -= m3 * r1[3];
 211    s = r1[4];
 212    if (0.0 != s) {
 213       r2[4] -= m2 * s;
 214       r3[4] -= m3 * s;
 215    }
 216    s = r1[5];
 217    if (0.0 != s) {
 218       r2[5] -= m2 * s;
 219       r3[5] -= m3 * s;
 220    }
 221    s = r1[6];
 222    if (0.0 != s) {
 223       r2[6] -= m2 * s;
 224       r3[6] -= m3 * s;
 225    }
 226    s = r1[7];
 227    if (0.0 != s) {
 228       r2[7] -= m2 * s;
 229       r3[7] -= m3 * s;
 230    }
 231
 232    /* choose pivot - or die */
 233    if (fabs(r3[2]) > fabs(r2[2]))
 234       SWAP_ROWS(r3, r2);
 235    if (0.0 == r2[2])
 236       return GL_FALSE;
 237
 238    /* eliminate third variable */
 239    m3 = r3[2] / r2[2];
 240    r3[3] -= m3 * r2[3], r3[4] -= m3 * r2[4],
 241       r3[5] -= m3 * r2[5], r3[6] -= m3 * r2[6], r3[7] -= m3 * r2[7];
 242
 243    /* last check */
 244    if (0.0 == r3[3])
 245       return GL_FALSE;
 246
 247    s = 1.0 / r3[3];             /* now back substitute row 3 */
 248    r3[4] *= s;
 249    r3[5] *= s;
 250    r3[6] *= s;
 251    r3[7] *= s;
 252
 253    m2 = r2[3];                  /* now back substitute row 2 */
 254    s = 1.0 / r2[2];
 255    r2[4] = s * (r2[4] - r3[4] * m2), r2[5] = s * (r2[5] - r3[5] * m2),
 256       r2[6] = s * (r2[6] - r3[6] * m2), r2[7] = s * (r2[7] - r3[7] * m2);
 257    m1 = r1[3];
 258    r1[4] -= r3[4] * m1, r1[5] -= r3[5] * m1,
 259       r1[6] -= r3[6] * m1, r1[7] -= r3[7] * m1;
 260    m0 = r0[3];
 261    r0[4] -= r3[4] * m0, r0[5] -= r3[5] * m0,
 262       r0[6] -= r3[6] * m0, r0[7] -= r3[7] * m0;
 263
 264    m1 = r1[2];                  /* now back substitute row 1 */
 265    s = 1.0 / r1[1];
 266    r1[4] = s * (r1[4] - r2[4] * m1), r1[5] = s * (r1[5] - r2[5] * m1),
 267       r1[6] = s * (r1[6] - r2[6] * m1), r1[7] = s * (r1[7] - r2[7] * m1);
 268    m0 = r0[2];
 269    r0[4] -= r2[4] * m0, r0[5] -= r2[5] * m0,
 270       r0[6] -= r2[6] * m0, r0[7] -= r2[7] * m0;
 271
 272    m0 = r0[1];                  /* now back substitute row 0 */
 273    s = 1.0 / r0[0];
 274    r0[4] = s * (r0[4] - r1[4] * m0), r0[5] = s * (r0[5] - r1[5] * m0),
 275       r0[6] = s * (r0[6] - r1[6] * m0), r0[7] = s * (r0[7] - r1[7] * m0);
 276
 277    MAT(out, 0, 0) = r0[4];
 278    MAT(out, 0, 1) = r0[5], MAT(out, 0, 2) = r0[6];
 279    MAT(out, 0, 3) = r0[7], MAT(out, 1, 0) = r1[4];
 280    MAT(out, 1, 1) = r1[5], MAT(out, 1, 2) = r1[6];
 281    MAT(out, 1, 3) = r1[7], MAT(out, 2, 0) = r2[4];
 282    MAT(out, 2, 1) = r2[5], MAT(out, 2, 2) = r2[6];
 283    MAT(out, 2, 3) = r2[7], MAT(out, 3, 0) = r3[4];
 284    MAT(out, 3, 1) = r3[5], MAT(out, 3, 2) = r3[6];
 285    MAT(out, 3, 3) = r3[7];
 286
 287    return GL_TRUE;
 288
 289 #undef MAT
 290 #undef SWAP_ROWS
 291 }
 292
 293
 294
 295 /* projection du point (objx,objy,obz) sur l'ecran (winx,winy,winz) */
 296 GLint GLAPIENTRY
 297 gluProject(GLdouble objx, GLdouble objy, GLdouble objz,
 298            const GLdouble model[16], const GLdouble proj[16],
 299            const GLint viewport[4],
 300            GLdouble * winx, GLdouble * winy, GLdouble * winz)
 301 {
 302    /* matrice de transformation */
 303    GLdouble in[4], out[4];
 304
 305    /* initilise la matrice et le vecteur a transformer */
 306    in[0] = objx;
 307    in[1] = objy;
 308    in[2] = objz;
 309    in[3] = 1.0;
 310    transform_point(out, model, in);
 311    transform_point(in, proj, out);
 312
 313    /* d'ou le resultat normalise entre -1 et 1 */
 314    if (in[3] == 0.0)
 315       return GL_FALSE;
 316
 317    in[0] /= in[3];
 318    in[1] /= in[3];
 319    in[2] /= in[3];
 320
 321    /* en coordonnees ecran */
 322    *winx = viewport[0] + (1 + in[0]) * viewport[2] / 2;
 323    *winy = viewport[1] + (1 + in[1]) * viewport[3] / 2;
 324    /* entre 0 et 1 suivant z */
 325    *winz = (1 + in[2]) / 2;
 326    return GL_TRUE;
 327 }
 328
 329
 330
 331 /* transformation du point ecran (winx,winy,winz) en point objet */
 332 GLint GLAPIENTRY
 333 gluUnProject(GLdouble winx, GLdouble winy, GLdouble winz,
 334              const GLdouble model[16], const GLdouble proj[16],
 335              const GLint viewport[4],
 336              GLdouble * objx, GLdouble * objy, GLdouble * objz)
 337 {
 338    /* matrice de transformation */
 339    GLdouble m[16], A[16];
 340    GLdouble in[4], out[4];
 341
 342    /* transformation coordonnees normalisees entre -1 et 1 */
 343    in[0] = (winx - viewport[0]) * 2 / viewport[2] - 1.0;
 344    in[1] = (winy - viewport[1]) * 2 / viewport[3] - 1.0;
 345    in[2] = 2 * winz - 1.0;
 346    in[3] = 1.0;
 347
 348    /* calcul transformation inverse */
 349    matmul(A, proj, model);
 350    invert_matrix(A, m);
 351
 352    /* d'ou les coordonnees objets */
 353    transform_point(out, m, in);
 354    if (out[3] == 0.0)
 355       return GL_FALSE;
 356    *objx = out[0] / out[3];
 357    *objy = out[1] / out[3];
 358    *objz = out[2] / out[3];
 359    return GL_TRUE;
 360 }
 361
 362
 363 /*
 364  * New in GLU 1.3
 365  * This is like gluUnProject but also takes near and far DepthRange values.
 366  */
 367 #ifdef GLU_VERSION_1_3
 368 GLint GLAPIENTRY
 369 gluUnProject4(GLdouble winx, GLdouble winy, GLdouble winz, GLdouble clipw,
 370               const GLdouble modelMatrix[16],
 371               const GLdouble projMatrix[16],
 372               const GLint viewport[4],
 373               GLclampd nearZ, GLclampd farZ,
 374               GLdouble * objx, GLdouble * objy, GLdouble * objz,
 375               GLdouble * objw)
 376 {
 377    /* matrice de transformation */
 378    GLdouble m[16], A[16];
 379    GLdouble in[4], out[4];
 380    GLdouble z = nearZ + winz * (farZ - nearZ);
 381
 382    /* transformation coordonnees normalisees entre -1 et 1 */
 383    in[0] = (winx - viewport[0]) * 2 / viewport[2] - 1.0;
 384    in[1] = (winy - viewport[1]) * 2 / viewport[3] - 1.0;
 385    in[2] = 2.0 * z - 1.0;
 386    in[3] = clipw;
 387
 388    /* calcul transformation inverse */
 389    matmul(A, projMatrix, modelMatrix);
 390    invert_matrix(A, m);
 391
 392    /* d'ou les coordonnees objets */
 393    transform_point(out, m, in);
 394    if (out[3] == 0.0)
 395       return GL_FALSE;
 396    *objx = out[0] / out[3];
 397    *objy = out[1] / out[3];
 398    *objz = out[2] / out[3];
 399    *objw = out[3];
 400    return GL_TRUE;
 401 }
 402 #endif