src/glu/mesa/project.c

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