src/glu/mesa/project.c

   1 /* $Id: project.c,v 1.2 1999/09/14 00:10:31 brianp Exp $ */
   2
   3 /*
   4  * Mesa 3-D graphics library
   5  * Version:  3.1
   6  * Copyright (C) 1995-1999  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 /*
  25  * $Log: project.c,v $
  26  * Revision 1.2  1999/09/14 00:10:31  brianp
  27  * added gluUnProject4()
  28  *
  29  * Revision 1.1.1.1  1999/08/19 00:55:42  jtg
  30  * Imported sources
  31  *
  32  * Revision 1.7  1999/01/03 03:23:15  brianp
  33  * now using GLAPIENTRY and GLCALLBACK keywords (Ted Jump)
  34  *
  35  * Revision 1.6  1998/07/08 01:43:43  brianp
  36  * new version of invert_matrix()  (also in src/matrix.c)
  37  *
  38  * Revision 1.5  1997/07/24 01:28:44  brianp
  39  * changed precompiled header symbol from PCH to PC_HEADER
  40  *
  41  * Revision 1.4  1997/05/28 02:29:38  brianp
  42  * added support for precompiled headers (PCH), inserted APIENTRY keyword
  43  *
  44  * Revision 1.3  1997/04/11 23:22:42  brianp
  45  * added divide by zero checks to gluProject() and gluUnproject()
  46  *
  47  * Revision 1.2  1997/01/29 19:05:29  brianp
  48  * faster invert_matrix() function from Stephane Rehel
  49  *
  50  * Revision 1.1  1996/09/27 01:19:39  brianp
  51  * Initial revision
  52  *
  53  */
  54
  55
  56 #ifdef PC_HEADER
  57 #include "all.h"
  58 #else
  59 #include <stdio.h>
  60 #include <string.h>
  61 #include <math.h>
  62 #include "gluP.h"
  63 #endif
  64
  65
  66 /*
  67  * This code was contributed by Marc Buffat (buffat@mecaflu.ec-lyon.fr).
  68  * Thanks Marc!!!
  69  */
  70
  71
  72
  73 /* implementation de gluProject et gluUnproject */
  74 /* M. Buffat 17/2/95 */
  75
  76
  77
  78 /*
  79  * Transform a point (column vector) by a 4x4 matrix.  I.e.  out = m * in
  80  * Input:  m - the 4x4 matrix
  81  *         in - the 4x1 vector
  82  * Output:  out - the resulting 4x1 vector.
  83  */
  84 static void transform_point( GLdouble out[4], const GLdouble m[16],
  85                              const GLdouble in[4] )
  86 {
  87 #define M(row,col)  m[col*4+row]
  88    out[0] = M(0,0) * in[0] + M(0,1) * in[1] + M(0,2) * in[2] + M(0,3) * in[3];
  89    out[1] = M(1,0) * in[0] + M(1,1) * in[1] + M(1,2) * in[2] + M(1,3) * in[3];
  90    out[2] = M(2,0) * in[0] + M(2,1) * in[1] + M(2,2) * in[2] + M(2,3) * in[3];
  91    out[3] = M(3,0) * in[0] + M(3,1) * in[1] + M(3,2) * in[2] + M(3,3) * in[3];
  92 #undef M
  93 }
  94
  95
  96
  97
  98 /*
  99  * Perform a 4x4 matrix multiplication  (product = a x b).
 100  * Input:  a, b - matrices to multiply
 101  * Output:  product - product of a and b
 102  */
 103 static void matmul( GLdouble *product, const GLdouble *a, const GLdouble *b )
 104 {
 105    /* This matmul was contributed by Thomas Malik */
 106    GLdouble temp[16];
 107    GLint i;
 108
 109 #define A(row,col)  a[(col<<2)+row]
 110 #define B(row,col)  b[(col<<2)+row]
 111 #define T(row,col)  temp[(col<<2)+row]
 112
 113    /* i-te Zeile */
 114    for (i = 0; i < 4; i++)
 115      {
 116         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);
 117         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);
 118         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);
 119         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);
 120      }
 121
 122 #undef A
 123 #undef B
 124 #undef T
 125    MEMCPY( product, temp, 16*sizeof(GLdouble) );
 126 }
 127
 128
 129
 130 /*
 131  * Compute inverse of 4x4 transformation matrix.
 132  * Code contributed by Jacques Leroy jle@star.be
 133  * Return GL_TRUE for success, GL_FALSE for failure (singular matrix)
 134  */
 135 static GLboolean invert_matrix( const GLdouble *m, GLdouble *out )
 136 {
 137 /* NB. OpenGL Matrices are COLUMN major. */
 138 #define SWAP_ROWS(a, b) { GLdouble *_tmp = a; (a)=(b); (b)=_tmp; }
 139 #define MAT(m,r,c) (m)[(c)*4+(r)]
 140
 141  GLdouble wtmp[4][8];
 142  GLdouble m0, m1, m2, m3, s;
 143  GLdouble *r0, *r1, *r2, *r3;
 144
 145  r0 = wtmp[0], r1 = wtmp[1], r2 = wtmp[2], r3 = wtmp[3];
 146
 147  r0[0] = MAT(m,0,0), r0[1] = MAT(m,0,1),
 148  r0[2] = MAT(m,0,2), r0[3] = MAT(m,0,3),
 149  r0[4] = 1.0, r0[5] = r0[6] = r0[7] = 0.0,
 150
 151  r1[0] = MAT(m,1,0), r1[1] = MAT(m,1,1),
 152  r1[2] = MAT(m,1,2), r1[3] = MAT(m,1,3),
 153  r1[5] = 1.0, r1[4] = r1[6] = r1[7] = 0.0,
 154
 155  r2[0] = MAT(m,2,0), r2[1] = MAT(m,2,1),
 156  r2[2] = MAT(m,2,2), r2[3] = MAT(m,2,3),
 157  r2[6] = 1.0, r2[4] = r2[5] = r2[7] = 0.0,
 158
 159  r3[0] = MAT(m,3,0), r3[1] = MAT(m,3,1),
 160  r3[2] = MAT(m,3,2), r3[3] = MAT(m,3,3),
 161  r3[7] = 1.0, r3[4] = r3[5] = r3[6] = 0.0;
 162
 163  /* choose pivot - or die */
 164  if (fabs(r3[0])>fabs(r2[0])) SWAP_ROWS(r3, r2);
 165  if (fabs(r2[0])>fabs(r1[0])) SWAP_ROWS(r2, r1);
 166  if (fabs(r1[0])>fabs(r0[0])) SWAP_ROWS(r1, r0);
 167  if (0.0 == r0[0])  return GL_FALSE;
 168
 169  /* eliminate first variable     */
 170  m1 = r1[0]/r0[0]; m2 = r2[0]/r0[0]; m3 = r3[0]/r0[0];
 171  s = r0[1]; r1[1] -= m1 * s; r2[1] -= m2 * s; r3[1] -= m3 * s;
 172  s = r0[2]; r1[2] -= m1 * s; r2[2] -= m2 * s; r3[2] -= m3 * s;
 173  s = r0[3]; r1[3] -= m1 * s; r2[3] -= m2 * s; r3[3] -= m3 * s;
 174  s = r0[4];
 175  if (s != 0.0) { r1[4] -= m1 * s; r2[4] -= m2 * s; r3[4] -= m3 * s; }
 176  s = r0[5];
 177  if (s != 0.0) { r1[5] -= m1 * s; r2[5] -= m2 * s; r3[5] -= m3 * s; }
 178  s = r0[6];
 179  if (s != 0.0) { r1[6] -= m1 * s; r2[6] -= m2 * s; r3[6] -= m3 * s; }
 180  s = r0[7];
 181  if (s != 0.0) { r1[7] -= m1 * s; r2[7] -= m2 * s; r3[7] -= m3 * s; }
 182
 183  /* choose pivot - or die */
 184  if (fabs(r3[1])>fabs(r2[1])) SWAP_ROWS(r3, r2);
 185  if (fabs(r2[1])>fabs(r1[1])) SWAP_ROWS(r2, r1);
 186  if (0.0 == r1[1])  return GL_FALSE;
 187
 188  /* eliminate second variable */
 189  m2 = r2[1]/r1[1]; m3 = r3[1]/r1[1];
 190  r2[2] -= m2 * r1[2]; r3[2] -= m3 * r1[2];
 191  r2[3] -= m2 * r1[3]; r3[3] -= m3 * r1[3];
 192  s = r1[4]; if (0.0 != s) { r2[4] -= m2 * s; r3[4] -= m3 * s; }
 193  s = r1[5]; if (0.0 != s) { r2[5] -= m2 * s; r3[5] -= m3 * s; }
 194  s = r1[6]; if (0.0 != s) { r2[6] -= m2 * s; r3[6] -= m3 * s; }
 195  s = r1[7]; if (0.0 != s) { r2[7] -= m2 * s; r3[7] -= m3 * s; }
 196
 197  /* choose pivot - or die */
 198  if (fabs(r3[2])>fabs(r2[2])) SWAP_ROWS(r3, r2);
 199  if (0.0 == r2[2])  return GL_FALSE;
 200
 201  /* eliminate third variable */
 202  m3 = r3[2]/r2[2];
 203  r3[3] -= m3 * r2[3], r3[4] -= m3 * r2[4],
 204  r3[5] -= m3 * r2[5], r3[6] -= m3 * r2[6],
 205  r3[7] -= m3 * r2[7];
 206
 207  /* last check */
 208  if (0.0 == r3[3]) return GL_FALSE;
 209
 210  s = 1.0/r3[3];              /* now back substitute row 3 */
 211  r3[4] *= s; r3[5] *= s; r3[6] *= s; r3[7] *= s;
 212
 213  m2 = r2[3];                 /* now back substitute row 2 */
 214  s  = 1.0/r2[2];
 215  r2[4] = s * (r2[4] - r3[4] * m2), r2[5] = s * (r2[5] - r3[5] * m2),
 216  r2[6] = s * (r2[6] - r3[6] * m2), r2[7] = s * (r2[7] - r3[7] * m2);
 217  m1 = r1[3];
 218  r1[4] -= r3[4] * m1, r1[5] -= r3[5] * m1,
 219  r1[6] -= r3[6] * m1, r1[7] -= r3[7] * m1;
 220  m0 = r0[3];
 221  r0[4] -= r3[4] * m0, r0[5] -= r3[5] * m0,
 222  r0[6] -= r3[6] * m0, r0[7] -= r3[7] * m0;
 223
 224  m1 = r1[2];                 /* now back substitute row 1 */
 225  s  = 1.0/r1[1];
 226  r1[4] = s * (r1[4] - r2[4] * m1), r1[5] = s * (r1[5] - r2[5] * m1),
 227  r1[6] = s * (r1[6] - r2[6] * m1), r1[7] = s * (r1[7] - r2[7] * m1);
 228  m0 = r0[2];
 229  r0[4] -= r2[4] * m0, r0[5] -= r2[5] * m0,
 230  r0[6] -= r2[6] * m0, r0[7] -= r2[7] * m0;
 231
 232  m0 = r0[1];                 /* now back substitute row 0 */
 233  s  = 1.0/r0[0];
 234  r0[4] = s * (r0[4] - r1[4] * m0), r0[5] = s * (r0[5] - r1[5] * m0),
 235  r0[6] = s * (r0[6] - r1[6] * m0), r0[7] = s * (r0[7] - r1[7] * m0);
 236
 237  MAT(out,0,0) = r0[4]; MAT(out,0,1) = r0[5],
 238  MAT(out,0,2) = r0[6]; MAT(out,0,3) = r0[7],
 239  MAT(out,1,0) = r1[4]; MAT(out,1,1) = r1[5],
 240  MAT(out,1,2) = r1[6]; MAT(out,1,3) = r1[7],
 241  MAT(out,2,0) = r2[4]; MAT(out,2,1) = r2[5],
 242  MAT(out,2,2) = r2[6]; MAT(out,2,3) = r2[7],
 243  MAT(out,3,0) = r3[4]; MAT(out,3,1) = r3[5],
 244  MAT(out,3,2) = r3[6]; MAT(out,3,3) = r3[7];
 245
 246  return GL_TRUE;
 247
 248 #undef MAT
 249 #undef SWAP_ROWS
 250 }
 251
 252
 253
 254 /* projection du point (objx,objy,obz) sur l'ecran (winx,winy,winz) */
 255 GLint GLAPIENTRY gluProject(GLdouble objx,GLdouble objy,GLdouble objz,
 256                           const GLdouble model[16],const GLdouble proj[16],
 257                           const GLint viewport[4],
 258                           GLdouble *winx,GLdouble *winy,GLdouble *winz)
 259 {
 260     /* matrice de transformation */
 261     GLdouble in[4],out[4];
 262
 263     /* initilise la matrice et le vecteur a transformer */
 264     in[0]=objx; in[1]=objy; in[2]=objz; in[3]=1.0;
 265     transform_point(out,model,in);
 266     transform_point(in,proj,out);
 267
 268     /* d'ou le resultat normalise entre -1 et 1*/
 269     if (in[3]==0.0)
 270        return GL_FALSE;
 271
 272     in[0]/=in[3]; in[1]/=in[3]; in[2]/=in[3];
 273
 274     /* en coordonnees ecran */
 275     *winx = viewport[0]+(1+in[0])*viewport[2]/2;
 276     *winy = viewport[1]+(1+in[1])*viewport[3]/2;
 277     /* entre 0 et 1 suivant z */
 278     *winz = (1+in[2])/2;
 279     return GL_TRUE;
 280 }
 281
 282
 283
 284 /* transformation du point ecran (winx,winy,winz) en point objet */
 285 GLint GLAPIENTRY gluUnProject(GLdouble winx,GLdouble winy,GLdouble winz,
 286                             const GLdouble model[16],const GLdouble proj[16],
 287                             const GLint viewport[4],
 288                             GLdouble *objx,GLdouble *objy,GLdouble *objz)
 289 {
 290     /* matrice de transformation */
 291     GLdouble m[16], A[16];
 292     GLdouble in[4],out[4];
 293
 294     /* transformation coordonnees normalisees entre -1 et 1 */
 295     in[0]=(winx-viewport[0])*2/viewport[2] - 1.0;
 296     in[1]=(winy-viewport[1])*2/viewport[3] - 1.0;
 297     in[2]=2*winz - 1.0;
 298     in[3]=1.0;
 299
 300     /* calcul transformation inverse */
 301     matmul(A,proj,model);
 302     invert_matrix(A,m);
 303
 304     /* d'ou les coordonnees objets */
 305     transform_point(out,m,in);
 306     if (out[3]==0.0)
 307        return GL_FALSE;
 308     *objx=out[0]/out[3];
 309     *objy=out[1]/out[3];
 310     *objz=out[2]/out[3];
 311     return GL_TRUE;
 312 }
 313
 314
 315 /*
 316  * New in GLU 1.3
 317  * This is like gluUnProject but also takes near and far DepthRange values.
 318  */
 319 GLint GLAPIENTRY
 320 gluUnProject4( GLdouble winx, GLdouble winy, GLdouble winz, GLdouble clipw,
 321                const GLdouble modelMatrix[16],
 322                const GLdouble projMatrix[16],
 323                const GLint viewport[4],
 324                GLclampd nearZ, GLclampd farZ,
 325                GLdouble *objx, GLdouble *objy, GLdouble *objz, GLdouble *objw )
 326 {
 327     /* matrice de transformation */
 328     GLdouble m[16], A[16];
 329     GLdouble in[4],out[4];
 330     GLdouble z = nearZ + winz * (farZ - nearZ);
 331
 332     /* transformation coordonnees normalisees entre -1 et 1 */
 333     in[0] = (winx-viewport[0])*2/viewport[2] - 1.0;
 334     in[1] = (winy-viewport[1])*2/viewport[3] - 1.0;
 335     in[2] = 2.0 * z - 1.0;
 336     in[3] = clipw;
 337
 338     /* calcul transformation inverse */
 339     matmul(A,projMatrix,modelMatrix);
 340     invert_matrix(A,m);
 341
 342     /* d'ou les coordonnees objets */
 343     transform_point(out,m,in);
 344     if (out[3]==0.0)
 345        return GL_FALSE;
 346     *objx=out[0]/out[3];
 347     *objy=out[1]/out[3];
 348     *objz=out[2]/out[3];
 349     *objw=out[3];
 350     return GL_TRUE;
 351 }