utils/glcanvas/samples/penguin/lw.c

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