samples/opengl/penguin/lw.cpp

   1 /*
   2  * Copyright (C) 1998 Janne Löf <jlof@mail.student.oulu.fi>
   3  *
   4  * This library is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU Library General Public
   6  * License as published by the Free Software Foundation; either
   7  * version 2 of the License, or (at your option) any later version.
   8  *
   9  * This library is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12  * Library General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU Library General Public
  15  * License along with this library; if not, write to the Free
  16  * Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  17  */
  18
  19 #ifdef __WXMSW__
  20 #include <windows.h>
  21 #endif
  22
  23 #include "lw.h"
  24 #include <stdlib.h>
  25 #include <stdio.h>
  26 #include <math.h>
  27
  28 #ifndef __WXMAC__
  29 // does this not give redefine errors on other platforms ?
  30 #define wxInt32 int
  31 #define wxUint32 unsigned int
  32 #endif
  33
  34 #ifndef FALSE
  35 #define FALSE 0
  36 #endif
  37
  38 #ifndef TRUE
  39 #define TRUE 1
  40 #endif
  41
  42 #define MK_ID(a,b,c,d) ((((wxUint32)(a))<<24)| \
  43                         (((wxUint32)(b))<<16)| \
  44                         (((wxUint32)(c))<< 8)| \
  45                         (((wxUint32)(d))    ))
  46
  47 #define ID_FORM MK_ID('F','O','R','M')
  48 #define ID_LWOB MK_ID('L','W','O','B')
  49 #define ID_PNTS MK_ID('P','N','T','S')
  50 #define ID_SRFS MK_ID('S','R','F','S')
  51 #define ID_SURF MK_ID('S','U','R','F')
  52 #define ID_POLS MK_ID('P','O','L','S')
  53 #define ID_COLR MK_ID('C','O','L','R')
  54
  55 static wxInt32 read_char(FILE *f)
  56 {
  57   int c = fgetc(f);
  58   return c;
  59 }
  60
  61 static wxInt32 read_short(FILE *f)
  62 {
  63     // the execution path was not always correct
  64     // when using the direct evaluation in the return statement
  65     wxInt32 first = read_char(f) ;
  66     wxInt32 second = read_char(f) ;
  67
  68   return (first<<8) | second ;
  69 }
  70
  71 static wxInt32 read_long(FILE *f)
  72 {
  73     // the execution path was not always correct
  74     // when using the direct evaluation in the return statement
  75     wxInt32 first = read_char(f) ;
  76     wxInt32 second = read_char(f) ;
  77     wxInt32 third = read_char(f) ;
  78     wxInt32 fourth = read_char(f) ;
  79   return (first<<24) | (second<<16) | (third<<8) | fourth ;
  80 }
  81
  82 static GLfloat read_float(FILE *f)
  83 {
  84   wxInt32 x = read_long(f);
  85   return *(GLfloat*)&x;
  86 }
  87
  88 static int read_string(FILE *f, char *s)
  89 {
  90   int c;
  91   int cnt = 0;
  92   do {
  93     c = read_char(f);
  94     if (cnt < LW_MAX_NAME_LEN)
  95       s[cnt] = c;
  96     else
  97       s[LW_MAX_NAME_LEN-1] = 0;
  98     cnt++;
  99   } while (c != 0);
 100   /* if length of string (including \0) is odd skip another byte */
 101   if (cnt%2) {
 102     read_char(f);
 103     cnt++;
 104   }
 105   return cnt;
 106 }
 107
 108 static void read_srfs(FILE *f, int nbytes, lwObject *lwo)
 109 {
 110   int guess_cnt = lwo->material_cnt;
 111
 112   while (nbytes > 0) {
 113     lwMaterial *material;
 114
 115     /* allocate more memory for materials if needed */
 116     if (guess_cnt <= lwo->material_cnt) {
 117       guess_cnt += guess_cnt/2 + 4;
 118       lwo->material = (lwMaterial*) realloc(lwo->material, sizeof(lwMaterial)*guess_cnt);
 119     }
 120     material = lwo->material + lwo->material_cnt++;
 121
 122     /* read name */
 123     nbytes -= read_string(f,material->name);
 124
 125     /* defaults */
 126     material->r = 0.7;
 127     material->g = 0.7;
 128     material->b = 0.7;
 129   }
 130   lwo->material = (lwMaterial*) realloc(lwo->material, sizeof(lwMaterial)*lwo->material_cnt);
 131 }
 132
 133
 134 static void read_surf(FILE *f, int nbytes, lwObject *lwo)
 135 {
 136   int i;
 137   char name[LW_MAX_NAME_LEN];
 138   lwMaterial *material = NULL;
 139
 140   /* read surface name */
 141   nbytes -= read_string(f,name);
 142
 143   /* find material */
 144   for (i=0; i< lwo->material_cnt; i++) {
 145     if (strcmp(lwo->material[i].name,name) == 0) {
 146       material = &lwo->material[i];
 147       break;
 148     }
 149   }
 150
 151   /* read values */
 152   while (nbytes > 0) {
 153     int id = read_long(f);
 154     int len = read_short(f);
 155     nbytes -= 6 + len + (len%2);
 156
 157     switch (id) {
 158     case ID_COLR:
 159       material->r = read_char(f) / 255.0;
 160       material->g = read_char(f) / 255.0;
 161       material->b = read_char(f) / 255.0;
 162       read_char(f); /* dummy */
 163       break;
 164     default:
 165       fseek(f, len+(len%2), SEEK_CUR);
 166     }
 167   }
 168 }
 169
 170
 171 static void read_pols(FILE *f, int nbytes, lwObject *lwo)
 172 {
 173   int guess_cnt = lwo->face_cnt;
 174
 175   while (nbytes > 0) {
 176     lwFace *face;
 177     int i;
 178
 179     /* allocate more memory for polygons if necessary */
 180     if (guess_cnt <= lwo->face_cnt) {
 181       guess_cnt += guess_cnt + 4;
 182       lwo->face = (lwFace*) realloc((void*) lwo->face, sizeof(lwFace)*guess_cnt);
 183     }
 184     face = lwo->face + lwo->face_cnt++;
 185
 186     /* number of points in this face */
 187     face->index_cnt = read_short(f);
 188     nbytes -= 2;
 189
 190     /* allocate space for points */
 191     face->index = (int*) calloc(sizeof(int)*face->index_cnt,1);
 192
 193     /* read points in */
 194     for (i=0; i<face->index_cnt; i++) {
 195       face->index[i] = read_short(f);
 196       nbytes -= 2;
 197     }
 198
 199     /* read surface material */
 200     face->material = read_short(f);
 201     nbytes -= 2;
 202
 203     /* skip over detail  polygons */
 204     if (face->material < 0) {
 205       int det_cnt;
 206       face->material = -face->material;
 207       det_cnt = read_short(f);
 208       nbytes -= 2;
 209       while (det_cnt-- > 0) {
 210         int cnt = read_short(f);
 211         fseek(f, cnt*2+2, SEEK_CUR);
 212         nbytes -= cnt*2+2;
 213       }
 214     }
 215     face->material -= 1;
 216   }
 217   /* readjust to true size */
 218   lwo->face = (lwFace*) realloc(lwo->face, sizeof(lwFace)*lwo->face_cnt);
 219 }
 220
 221
 222
 223 static void read_pnts(FILE *f, int nbytes, lwObject *lwo)
 224 {
 225   int i;
 226   lwo->vertex_cnt = nbytes / 12;
 227   lwo->vertex = (float*) calloc(sizeof(GLfloat)*lwo->vertex_cnt*3, 1);
 228   for (i=0; i<lwo->vertex_cnt; i++) {
 229     lwo->vertex[i*3+0] = read_float(f);
 230     lwo->vertex[i*3+1] = read_float(f);
 231     lwo->vertex[i*3+2] = read_float(f);
 232   }
 233 }
 234
 235
 236
 237
 238
 239
 240 int lw_is_lwobject(const char *lw_file)
 241 {
 242   FILE *f = fopen(lw_file, "rb");
 243   if (f) {
 244     wxInt32 form = read_long(f);
 245     wxInt32 nlen = read_long(f);
 246     wxInt32 lwob = read_long(f);
 247     fclose(f);
 248     if (form == ID_FORM && nlen != 0 && lwob == ID_LWOB)
 249       return TRUE;
 250   }
 251   return FALSE;
 252 }
 253
 254
 255 lwObject *lw_object_read(const char *lw_file)
 256 {
 257   FILE *f = NULL;
 258   lwObject *lw_object = NULL;
 259
 260   wxInt32 form_bytes = 0;
 261   wxInt32 read_bytes = 0;
 262
 263   /* open file */
 264   f = fopen(lw_file, "rb");
 265   if (f == NULL) {
 266     return NULL;
 267   }
 268
 269   /* check for headers */
 270   if (read_long(f) != ID_FORM) {
 271     fclose(f);
 272     return NULL;
 273   }
 274   form_bytes = read_long(f);
 275   read_bytes += 4;
 276
 277   if (read_long(f) != ID_LWOB) {
 278     fclose(f);
 279     return NULL;
 280   }
 281
 282   /* create new lwObject */
 283   lw_object = (lwObject*) calloc(sizeof(lwObject),1);
 284
 285   /* read chunks */
 286   while (read_bytes < form_bytes) {
 287     wxInt32  id     = read_long(f);
 288     wxInt32  nbytes = read_long(f);
 289     read_bytes += 8 + nbytes + (nbytes%2);
 290
 291     switch (id) {
 292     case ID_PNTS:
 293       read_pnts(f, nbytes, lw_object);
 294       break;
 295     case ID_POLS:
 296       read_pols(f, nbytes, lw_object);
 297       break;
 298     case ID_SRFS:
 299       read_srfs(f, nbytes, lw_object);
 300       break;
 301     case ID_SURF:
 302       read_surf(f, nbytes, lw_object);
 303       break;
 304     default:
 305       fseek(f, nbytes + (nbytes%2), SEEK_CUR);
 306     }
 307   }
 308
 309   fclose(f);
 310   return lw_object;
 311 }
 312
 313
 314
 315 void lw_object_free(lwObject *lw_object)
 316 {
 317   if (lw_object->face) {
 318     int i;
 319     for (i=0; i<lw_object->face_cnt; i++)
 320       free(lw_object->face[i].index);
 321     free(lw_object->face);
 322   }
 323   free(lw_object->material);
 324   free(lw_object->vertex);
 325   free(lw_object);
 326 }
 327
 328
 329
 330
 331
 332 #define PX(i) (lw_object->vertex[face->index[i]*3+0])
 333 #define PY(i) (lw_object->vertex[face->index[i]*3+1])
 334 #define PZ(i) (lw_object->vertex[face->index[i]*3+2])
 335 void lw_object_show(const lwObject *lw_object)
 336 {
 337   int i,j;
 338   int prev_index_cnt = -1;
 339   int prev_material  = -1;
 340   GLfloat prev_nx = 0;
 341   GLfloat prev_ny = 0;
 342   GLfloat prev_nz = 0;
 343
 344   for (i=0; i<lw_object->face_cnt; i++) {
 345     GLfloat ax,ay,az,bx,by,bz,nx,ny,nz,r;
 346     const lwFace *face = lw_object->face+i;
 347
 348     /* ignore faces with less than 3 points */
 349     if (face->index_cnt < 3)
 350       continue;
 351
 352     /* calculate normal */
 353     ax = PX(1) - PX(0);
 354     ay = PY(1) - PY(0);
 355     az = PZ(1) - PZ(0);
 356
 357     bx = PX(face->index_cnt-1) - PX(0);
 358     by = PY(face->index_cnt-1) - PY(0);
 359     bz = PZ(face->index_cnt-1) - PZ(0);
 360
 361     nx = ay * bz - az * by;
 362     ny = az * bx - ax * bz;
 363     nz = ax * by - ay * bx;
 364
 365     r = sqrt(nx*nx + ny*ny + nz*nz);
 366     if (r < 0.000001) /* avoid division by zero */
 367       continue;
 368     nx /= r;
 369     ny /= r;
 370     nz /= r;
 371
 372     /* glBegin/glEnd */
 373     if (prev_index_cnt != face->index_cnt || prev_index_cnt > 4) {
 374       if (prev_index_cnt > 0) glEnd();
 375       prev_index_cnt = face->index_cnt;
 376       switch (face->index_cnt) {
 377       case 3:
 378         glBegin(GL_TRIANGLES);
 379         break;
 380       case 4:
 381         glBegin(GL_QUADS);
 382         break;
 383       default:
 384         glBegin(GL_POLYGON);
 385       }
 386     }
 387
 388     /* update material if necessary */
 389     if (prev_material != face->material) {
 390       prev_material = face->material;
 391       glColor3f(lw_object->material[face->material].r,
 392                 lw_object->material[face->material].g,
 393                 lw_object->material[face->material].b);
 394     }
 395
 396     /* update normal if necessary */
 397     if (nx != prev_nx || ny != prev_ny || nz != prev_nz) {
 398       prev_nx = nx;
 399       prev_ny = ny;
 400       prev_nz = nz;
 401       glNormal3f(nx,ny,nz);
 402     }
 403
 404     /* draw polygon/triangle/quad */
 405     for (j=0; j<face->index_cnt; j++)
 406       glVertex3f(PX(j),PY(j),PZ(j));
 407
 408   }
 409
 410   /* if glBegin was called call glEnd */
 411   if (prev_index_cnt > 0)
 412     glEnd();
 413 }
 414
 415
 416 GLfloat lw_object_radius(const lwObject *lwo)
 417 {
 418   int i;
 419   double max_radius = 0.0;
 420
 421   for (i=0; i<lwo->vertex_cnt; i++) {
 422     GLfloat *v = &lwo->vertex[i*3];
 423     double r = v[0]*v[0] + v[1]*v[1] + v[2]*v[2];
 424     if (r > max_radius)
 425       max_radius = r;
 426   }
 427   return sqrt(max_radius);
 428 }
 429
 430 void lw_object_scale(lwObject *lwo, GLfloat scale)
 431 {
 432   int i;
 433
 434   for (i=0; i<lwo->vertex_cnt; i++) {
 435     lwo->vertex[i*3+0] *= scale;
 436     lwo->vertex[i*3+1] *= scale;
 437     lwo->vertex[i*3+2] *= scale;
 438   }
 439 }
 440
 441