src/image.c

   1 /*
   2  * 2ooM: The Master of Orion II Reverse Engineering Project
   3  * Library for working with LBX image files.
   4  * Copyright © 2006-2011, 2013 Nick Bowler
   5  *
   6  * This program is free software: you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation, either version 3 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  18  */
  19 #include <config.h>
  20 #include <stdlib.h>
  21 #include <string.h>
  22 #include <assert.h>
  23 #include <errno.h>
  24
  25 #include "pack.h"
  26 #include "misc.h"
  27 #include "lbx.h"
  28 #include "error.h"
  29 #include "image.h"
  30
  31 #define FLAG_RAW       0x0100 /* Image is stored as a flat array of bytes. */
  32 #define FLAG_OVERWRITE 0x0400 /* Draw each frame on a clean slate (unsure). */
  33 #define FLAG_BUILDING  0x0800 /* Buildings have this, related to shadow? */
  34 #define FLAG_PALETTE   0x1000 /* Image contains embedded palette. */
  35 #define FLAG_LOOPING   0x2000 /* Loop over all frames in the image (unsure). */
  36
  37 #define FLAG_ALL (FLAG_RAW|FLAG_OVERWRITE|FLAG_BUILDING|FLAG_PALETTE|FLAG_LOOPING)
  38
  39 #define HDR_LEN 12
  40
  41 struct lbx_image_priv {
  42         struct lbx_image pub;
  43
  44         unsigned short wtf, flags;
  45         unsigned char  wtf2, leadin;
  46         unsigned short palstart, palcount;
  47
  48         const struct lbx_file_ops *fops;
  49         int (*dtor)(void *handle);
  50         void *f;
  51
  52         long paloff;
  53
  54         int currentframe;
  55         int currentx, currenty;
  56         unsigned char **framedata;
  57         unsigned char **mask;
  58
  59         unsigned long offsets[];
  60 };
  61
  62 static struct lbx_image_priv *lbx_img_init(unsigned char hdr[static HDR_LEN])
  63 {
  64         unsigned short nframes = unpack_16_le(hdr+6);
  65         struct lbx_image_priv *img;
  66
  67         img = malloc(sizeof *img + sizeof img->offsets[0] * (nframes+1));
  68         if (!img) {
  69                 lbx_error_raise(LBX_ENOMEM);
  70                 return NULL;
  71         }
  72
  73         *img = (struct lbx_image_priv) {
  74                 .pub.width  = unpack_16_le(hdr+0),
  75                 .pub.height = unpack_16_le(hdr+2),
  76                 .wtf        = unpack_16_le(hdr+4),
  77                 .pub.frames = hdr[6],
  78                 .wtf2       = hdr[7],
  79                 .leadin     = hdr[8],
  80                 .pub.chunk  = hdr[9],
  81                 .flags      = unpack_16_le(hdr+10),
  82
  83                 .currentframe = -1,
  84         };
  85
  86         return img;
  87 }
  88
  89 struct lbx_image *lbx_img_open(void *f, const struct lbx_file_ops *fops,
  90                                int (*destructor)(void *))
  91 {
  92         unsigned char hdr_buf[HDR_LEN];
  93         struct lbx_image_priv *img;
  94
  95         if (fops->read(hdr_buf, sizeof hdr_buf, f) != sizeof hdr_buf) {
  96                 if (fops->eof(f))
  97                         lbx_error_raise(LBX_EEOF);
  98                 return NULL;
  99         }
 100
 101         img = lbx_img_init(hdr_buf);
 102         if (!img)
 103                 return NULL;
 104
 105         img->f    = f;
 106         img->fops = fops;
 107         img->dtor = destructor;
 108
 109         /*
 110          * DEBUG ONLY.  These assertions exist to catch otherwise valid image
 111          * files which differ from what I believe to be true of all LBX images.
 112          * When we can decode every image, then these assertions should be
 113          * replaced with constraints.
 114          */
 115         _lbx_assert(img->wtf  == 0); /* version? */
 116         _lbx_assert(img->wtf2 == 0); /* very likely is simply reserved. */
 117         _lbx_assert(img->pub.frames > img->leadin);
 118         _lbx_assert(!(img->flags & ~FLAG_ALL));
 119
 120         /* Read all offsets.  Should be merged with identical code in lbx.c */
 121         for (unsigned i = 0; i <= img->pub.frames; i++) {
 122                 unsigned char buf[4];
 123
 124                 if (fops->read(buf, sizeof buf, f) != sizeof buf) {
 125                         if (fops->eof(f))
 126                                 lbx_error_raise(LBX_EEOF);
 127                         free(img);
 128                         return NULL;
 129                 }
 130
 131                 img->offsets[i] = unpack_32_le(buf);
 132         }
 133
 134         if (img->flags & FLAG_PALETTE) {
 135                 unsigned char buf[4];
 136
 137                 if (fops->read(buf, sizeof buf, f) != sizeof buf) {
 138                         if (fops->eof(f))
 139                                 lbx_error_raise(LBX_EEOF);
 140                         free(img);
 141                         return NULL;
 142                 }
 143
 144                 img->palstart = unpack_16_le(buf+0);
 145                 img->palcount = unpack_16_le(buf+2);
 146                 img->paloff   = fops->tell(f);
 147
 148                 if (img->palstart + img->palcount > 256) {
 149                         lbx_error_raise(LBX_EFORMAT);
 150                         free(img);
 151                         return NULL;
 152                 }
 153         }
 154
 155         return &img->pub;
 156 }
 157
 158 static int pipe_close(void *f)
 159 {
 160         struct lbx_pipe_state *p = f;
 161         int rc;
 162
 163         rc = fclose(p->f);
 164         free(p);
 165         return rc;
 166 }
 167
 168 static int file_close(void *f)
 169 {
 170         return fclose((FILE *)f);
 171 }
 172
 173 struct lbx_image *lbx_img_fopen(const char *file)
 174 {
 175         struct lbx_pipe_state *p;
 176         FILE *f;
 177
 178         f = fopen(file, "rb");
 179         if (!f) {
 180                 lbx_error_raise(-errno);
 181                 return NULL;
 182         }
 183
 184         if (fseek(f, 0, SEEK_CUR) == 0)
 185                 return lbx_img_open(f, &lbx_default_fops, file_close);
 186
 187         p = malloc(sizeof *p);
 188         if (!p) {
 189                 lbx_error_raise(LBX_ENOMEM);
 190                 fclose(f);
 191                 return NULL;
 192         }
 193
 194         *p = (struct lbx_pipe_state) { .f = f };
 195         return lbx_img_open(p, &lbx_pipe_fops, pipe_close);
 196 }
 197
 198 static int _lbx_drawrow(int first, struct lbx_image_priv *img)
 199 {
 200         unsigned short type, count, yval, xval;
 201         unsigned char buf[4];
 202         unsigned char *pos;
 203         size_t rc;
 204
 205         assert(img->framedata);
 206         assert(img->mask);
 207
 208         if (img->fops->read(buf, sizeof buf, img->f) != sizeof buf)
 209                 goto readerr;
 210         type = unpack_16_le(buf+0);
 211
 212         if (first) {
 213                 img->currentx = 0;
 214                 img->currenty = 0;
 215                 type = 0;
 216         }
 217
 218         if (type == 0) {
 219                 yval = unpack_16_le(buf+2);
 220                 if (yval == 1000)
 221                         return 1;
 222
 223                 if (img->fops->read(buf, sizeof buf, img->f) != sizeof buf)
 224                         goto readerr;
 225                 count = unpack_16_le(buf+0);
 226
 227                 xval = unpack_16_le(buf+2);
 228                 if (xval == 1000)
 229                         return 1;
 230
 231                 /* Ensure that the row fits in the image. */
 232                 if (img->pub.height - img->currenty <= yval
 233                     || xval >= img->pub.width) {
 234                         lbx_error_raise(LBX_EFORMAT);
 235                         return -1;
 236                 }
 237
 238                 img->currenty += yval;
 239                 img->currentx  = xval;
 240         } else {
 241                 xval = unpack_16_le(buf+2);
 242
 243                 if (img->pub.width - img->currentx <= xval) {
 244                         lbx_error_raise(LBX_EFORMAT);
 245                         return -1;
 246                 }
 247                 img->currentx += xval;
 248
 249                 count = type;
 250         }
 251
 252         if (count > img->pub.width - img->currentx) {
 253                 lbx_error_raise(LBX_EFORMAT);
 254                 return -1;
 255         }
 256
 257         memset(&img->mask[img->currenty][img->currentx], 1, count);
 258
 259         pos = &img->framedata[img->currenty][img->currentx];
 260         rc  = img->fops->read(pos, count, img->f);
 261         img->currentx += rc;
 262
 263         if (rc < count)
 264                 goto readerr;
 265
 266         if (count % 2) {
 267                 if (img->fops->read(buf, 1, img->f) != 1)
 268                         goto readerr;
 269         }
 270
 271         return 0;
 272 readerr:
 273         if (img->fops->eof(img->f))
 274                 lbx_error_raise(LBX_EEOF);
 275         return -1;
 276 }
 277
 278 static unsigned char **allocframebuffer(size_t width, size_t height)
 279 {
 280         unsigned char **new, *tmp;
 281         size_t i;
 282
 283         tmp = calloc(height, width);
 284         if (!tmp) {
 285                 lbx_error_raise(LBX_ENOMEM);
 286                 return NULL;
 287         }
 288
 289         new = malloc(height * sizeof *new);
 290         if (!new) {
 291                 lbx_error_raise(LBX_ENOMEM);
 292                 free(tmp);
 293                 return NULL;
 294         }
 295
 296         for (i = 0; i < height; i++) {
 297                 new[i] = tmp + i * width;
 298         }
 299
 300         return new;
 301 }
 302
 303 static unsigned char **read_raw_frame(struct lbx_image_priv *img, int frame)
 304 {
 305         unsigned long size = img->pub.width * img->pub.height;
 306
 307         assert(img->flags & FLAG_RAW);
 308
 309         if (img->fops->seek(img->f, img->offsets[frame], SEEK_SET)) {
 310                 return NULL;
 311         }
 312
 313         if (img->fops->read(img->framedata[0], size, img->f) != size) {
 314                 if (img->fops->eof(img->f))
 315                         lbx_error_raise(LBX_EEOF);
 316                 return NULL;
 317         }
 318         memset(img->mask[0], 1, size);
 319
 320         if (img->fops->tell(img->f) > img->offsets[frame+1]) {
 321                 lbx_error_raise(LBX_EFORMAT);
 322                 return NULL;
 323         }
 324
 325         return img->framedata;
 326 }
 327
 328 unsigned char **lbx_img_getframe(struct lbx_image *pub, int frame)
 329 {
 330         struct lbx_image_priv *img = (struct lbx_image_priv *)pub;
 331
 332         if (frame >= pub->frames || frame < 0) {
 333                 lbx_error_raise(LBX_ENOENT);
 334                 return NULL;
 335         }
 336
 337         if (!img->framedata) {
 338                 img->framedata = allocframebuffer(pub->width, pub->height);
 339                 if (!img->framedata)
 340                         return NULL;
 341         }
 342
 343         if (!img->mask) {
 344                 img->mask = allocframebuffer(pub->width, pub->height);
 345                 if (!img->mask)
 346                         return NULL;
 347         }
 348
 349         if (img->flags & FLAG_RAW)
 350                 return read_raw_frame(img, frame);
 351
 352         if ((img->flags & FLAG_OVERWRITE)
 353              || (pub->chunk && !(frame % pub->chunk))) {
 354                 /* Clear the slate. */
 355                 img->currentframe = -1;
 356                 memset(img->framedata[0], 0, pub->width * pub->height);
 357                 memset(img->mask[0],      0, pub->width * pub->height);
 358         } else {
 359                 /* Start over if we are backtracking. */
 360                 if (img->currentframe > frame) {
 361                         memset(img->mask[0], 0, pub->width * pub->height);
 362                         img->currentframe = -1;
 363                 }
 364
 365                 /* We must have previous frame decoded to continue. */
 366                 if (frame > img->currentframe + 1) {
 367                         if (!lbx_img_getframe(pub, frame-1))
 368                                 return NULL;
 369                 }
 370         }
 371
 372         if (img->currentframe != frame) {
 373                 int rc, first = 1;
 374
 375                 if (img->fops->seek(img->f, img->offsets[frame], SEEK_SET)) {
 376                         return NULL;
 377                 }
 378
 379                 do {
 380                         rc = _lbx_drawrow(first, img);
 381                         if (rc == -1)
 382                                 return NULL;
 383                         first = 0;
 384
 385                         if (img->fops->tell(img->f) > img->offsets[frame+1]) {
 386                                 lbx_error_raise(LBX_EFORMAT);
 387                                 return NULL;
 388                         }
 389                 } while (!rc);
 390         }
 391
 392         img->currentframe = frame;
 393         return img->framedata;
 394 }
 395
 396 int
 397 lbx_img_loadpalette(void *f, const struct lbx_file_ops *fops,
 398                     struct lbx_colour palette[static 256])
 399 {
 400         unsigned char entry[4];
 401         int i;
 402
 403         for (i = 0; i < 256; i++) {
 404                 if (fops->read(entry, sizeof entry, f) != sizeof entry) {
 405                         if (fops->eof(f))
 406                                 lbx_error_raise(LBX_EEOF);
 407                         return -1;
 408                 }
 409
 410                 if (entry[0] != 1) {
 411                         lbx_error_raise(LBX_EFORMAT);
 412                         return -1;
 413                 }
 414
 415                 palette[i] = (struct lbx_colour) {
 416                         .red    = entry[1] << 2,
 417                         .green  = entry[2] << 2,
 418                         .blue   = entry[3] << 2,
 419                         .active = 1,
 420                 };
 421         }
 422
 423         return 0;
 424 }
 425
 426 int
 427 lbx_img_getpalette(struct lbx_image *pub, struct lbx_colour palette[static 256])
 428 {
 429         struct lbx_image_priv *img = (struct lbx_image_priv *)pub;
 430         unsigned char entry[4];
 431         unsigned int i;
 432         size_t rc;
 433
 434         /* Do nothing if the image doesn't have embedded palette data. */
 435         if (!(img->flags & FLAG_PALETTE))
 436                 return 0;
 437
 438         if (img->fops->seek(img->f, img->paloff, SEEK_SET)) {
 439                 return -1;
 440         }
 441
 442         for (i = 0; i < img->palcount; i++) {
 443                 rc = img->fops->read(entry, sizeof entry, img->f);
 444                 if (rc < sizeof entry) {
 445                         goto readerr;
 446                 }
 447
 448                 if (entry[0] != 0) {
 449                         lbx_error_raise(LBX_EFORMAT);
 450                         return -1;
 451                 }
 452
 453                 palette[img->palstart + i] = (struct lbx_colour){
 454                         .red    = entry[1] << 2,
 455                         .green  = entry[2] << 2,
 456                         .blue   = entry[3] << 2,
 457                         .active = 1,
 458                 };
 459         }
 460
 461         return 0;
 462 readerr:
 463         if (img->fops->eof(img->f))
 464                 lbx_error_raise(LBX_EEOF);
 465         return -1;
 466 }
 467
 468 void lbx_img_getinfo(struct lbx_image *pub, struct lbx_imginfo *info)
 469 {
 470         struct lbx_image_priv *img = (struct lbx_image_priv *)pub;
 471
 472         *info = (struct lbx_imginfo) {
 473                 .palettesz  = (img->flags & FLAG_PALETTE) ? img->palcount : 0,
 474         };
 475
 476         /* There seems to be two ways of specifying that an image loops. */
 477         if (img->flags & FLAG_LOOPING) {
 478                 info->loopstart = 0;
 479                 info->looping   = 1;
 480         } else if (img->leadin != pub->frames - 1) {
 481                 info->loopstart = img->leadin;
 482                 info->looping   = 1;
 483         }
 484 }
 485
 486 unsigned char **lbx_img_getmask(struct lbx_image *pub)
 487 {
 488         struct lbx_image_priv *img = (struct lbx_image_priv *)pub;
 489
 490         return img->mask;
 491 }
 492
 493 int lbx_img_close(struct lbx_image *pub)
 494 {
 495         struct lbx_image_priv *img = (struct lbx_image_priv *)pub;
 496         int rc = 0;
 497
 498         if (img) {
 499                 if (img->framedata) {
 500                         free(img->framedata[0]);
 501                         free(img->framedata);
 502                 }
 503
 504                 if (img->mask) {
 505                         free(img->mask[0]);
 506                         free(img->mask);
 507                 }
 508
 509                 if (img && img->dtor) {
 510                         rc = img->dtor(img->f);
 511                 }
 512
 513                 free(img);
 514         }
 515
 516         return rc;
 517 }