src/image.c

   1 /*
   2  *  2ooM: The Master of Orion II Reverse Engineering Project
   3  *  Library for working with LBX image files.
   4  *  Copyright (C) 2006-2010 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 {
  42         unsigned short width, height;
  43         unsigned short wtf, flags;
  44         unsigned char  frames, wtf2, leadin, chunk;
  45         unsigned short palstart, palcount;
  46
  47         const struct lbx_file_ops *fops;
  48         int (*dtor)(void *handle);
  49         void *f;
  50
  51         long paloff;
  52
  53         int currentframe;
  54         int currentx, currenty;
  55         unsigned char **framedata;
  56         unsigned char **mask;
  57
  58         unsigned long offsets[];
  59 };
  60
  61 static struct lbx_image *lbximg_init(unsigned char hdr[static HDR_LEN])
  62 {
  63         unsigned short nframes = unpack_16_le(hdr+6);
  64         struct lbx_image *img;
  65
  66         img = malloc(sizeof *img + sizeof img->offsets[0] * (nframes+1));
  67         if (!img) {
  68                 lbx_error_raise(LBX_ENOMEM);
  69                 return NULL;
  70         }
  71
  72         *img = (struct lbx_image) {
  73                 .width  = unpack_16_le(hdr+0),
  74                 .height = unpack_16_le(hdr+2),
  75                 .wtf    = unpack_16_le(hdr+4),
  76                 .frames = hdr[6],
  77                 .wtf2   = hdr[7],
  78                 .leadin = hdr[8],
  79                 .chunk  = hdr[9],
  80                 .flags  = unpack_16_le(hdr+10),
  81
  82                 .currentframe = -1,
  83         };
  84
  85         return img;
  86 }
  87
  88 struct lbx_image *lbximg_open(void *f, const struct lbx_file_ops *fops,
  89                               int (*destructor)(void *))
  90 {
  91         unsigned char hdr_buf[HDR_LEN];
  92         struct lbx_image *img;
  93
  94         if (fops->read(hdr_buf, sizeof hdr_buf, f) != sizeof hdr_buf) {
  95                 if (fops->eof(f))
  96                         lbx_error_raise(LBX_EEOF);
  97                 return NULL;
  98         }
  99
 100         img = lbximg_init(hdr_buf);
 101         if (!img)
 102                 return NULL;
 103
 104         img->f    = f;
 105         img->fops = fops;
 106         img->dtor = destructor;
 107
 108         /*
 109          * DEBUG ONLY.  These assertions exist to catch otherwise valid image
 110          * files which differ from what I believe to be true of all LBX images.
 111          * When we can decode every image, then these assertions should be
 112          * replaced with constraints.
 113          */
 114         _lbx_assert(img->wtf  == 0); /* version? */
 115         _lbx_assert(img->wtf2 == 0); /* very likely is simply reserved. */
 116         _lbx_assert(img->frames > img->leadin);
 117         _lbx_assert(!(img->flags & ~FLAG_ALL));
 118
 119         /* Read all offsets.  Should be merged with identical code in lbx.c */
 120         for (unsigned i = 0; i <= img->frames; i++) {
 121                 unsigned char buf[4];
 122
 123                 if (fops->read(buf, sizeof buf, f) != sizeof buf) {
 124                         if (fops->eof(f))
 125                                 lbx_error_raise(LBX_EEOF);
 126                         free(img);
 127                         return NULL;
 128                 }
 129
 130                 img->offsets[i] = unpack_32_le(buf);
 131         }
 132
 133         if (img->flags & FLAG_PALETTE) {
 134                 unsigned char buf[4];
 135
 136                 if (fops->read(buf, sizeof buf, f) != sizeof buf) {
 137                         if (fops->eof(f))
 138                                 lbx_error_raise(LBX_EEOF);
 139                         free(img);
 140                         return NULL;
 141                 }
 142
 143                 img->palstart = unpack_16_le(buf+0);
 144                 img->palcount = unpack_16_le(buf+2);
 145                 img->paloff   = fops->tell(f);
 146
 147                 if (img->palstart + img->palcount > 256) {
 148                         lbx_error_raise(LBX_EFORMAT);
 149                         free(img);
 150                         return NULL;
 151                 }
 152         }
 153
 154         return img;
 155 }
 156
 157 static int pipe_close(void *f)
 158 {
 159         struct lbx_pipe_state *p = f;
 160         int rc;
 161
 162         rc = fclose(p->f);
 163         free(p);
 164         return rc;
 165 }
 166
 167 static int file_close(void *f)
 168 {
 169         return fclose((FILE *)f);
 170 }
 171
 172 struct lbx_image *lbximg_fopen(const char *file)
 173 {
 174         struct lbx_pipe_state *p;
 175         FILE *f;
 176
 177         f = fopen(file, "rb");
 178         if (!f)
 179                 return NULL;
 180
 181         if (fseek(f, 0, SEEK_CUR) == 0)
 182                 return lbximg_open(f, &lbx_default_fops, file_close);
 183
 184         p = malloc(sizeof *p);
 185         if (!p) {
 186                 fclose(f);
 187                 return NULL;
 188         }
 189
 190         *p = (struct lbx_pipe_state) { .f = f };
 191         return lbximg_open(p, &lbx_pipe_fops, pipe_close);
 192 }
 193
 194 static int _lbx_drawrow(int first, struct lbx_image *img)
 195 {
 196         unsigned short type, count, yval, xval;
 197         unsigned char buf[4];
 198         unsigned char *pos;
 199         size_t rc;
 200
 201         assert(img->framedata);
 202         assert(img->mask);
 203
 204         if (img->fops->read(buf, sizeof buf, img->f) != sizeof buf)
 205                 goto readerr;
 206         type = unpack_16_le(buf+0);
 207
 208         if (first) {
 209                 img->currentx = 0;
 210                 img->currenty = 0;
 211                 type = 0;
 212         }
 213
 214         if (type == 0) {
 215                 yval = unpack_16_le(buf+2);
 216                 if (yval == 1000)
 217                         return 1;
 218
 219                 if (img->fops->read(buf, sizeof buf, img->f) != sizeof buf)
 220                         goto readerr;
 221                 count = unpack_16_le(buf+0);
 222
 223                 xval = unpack_16_le(buf+2);
 224                 if (xval == 1000)
 225                         return 1;
 226
 227                 /* Ensure that the row fits in the image. */
 228                 if (img->height - img->currenty <= yval || xval >= img->width) {
 229                         lbx_error_raise(LBX_EFORMAT);
 230                         return -1;
 231                 }
 232
 233                 img->currenty += yval;
 234                 img->currentx  = xval;
 235         } else {
 236                 xval = unpack_16_le(buf+2);
 237
 238                 if (img->width - img->currentx <= xval) {
 239                         lbx_error_raise(LBX_EFORMAT);
 240                         return -1;
 241                 }
 242                 img->currentx += xval;
 243
 244                 count = type;
 245         }
 246
 247         if (count > img->width - img->currentx) {
 248                 lbx_error_raise(LBX_EFORMAT);
 249                 return -1;
 250         }
 251
 252         memset(&img->mask[img->currenty][img->currentx], 1, count);
 253
 254         pos = &img->framedata[img->currenty][img->currentx];
 255         rc  = img->fops->read(pos, count, img->f);
 256         img->currentx += rc;
 257
 258         if (rc < count)
 259                 goto readerr;
 260
 261         if (count % 2) {
 262                 if (img->fops->read(buf, 1, img->f) != 1)
 263                         goto readerr;
 264         }
 265
 266         return 0;
 267 readerr:
 268         if (img->fops->eof(img->f))
 269                 lbx_error_raise(LBX_EEOF);
 270         return -1;
 271 }
 272
 273 static unsigned char **allocframebuffer(size_t width, size_t height)
 274 {
 275         unsigned char **new, *tmp;
 276         size_t i;
 277
 278         tmp = calloc(height, width);
 279         if (!tmp) {
 280                 lbx_error_raise(LBX_ENOMEM);
 281                 return NULL;
 282         }
 283
 284         new = malloc(height * sizeof *new);
 285         if (!new) {
 286                 lbx_error_raise(LBX_ENOMEM);
 287                 free(tmp);
 288                 return NULL;
 289         }
 290
 291         for (i = 0; i < height; i++) {
 292                 new[i] = tmp + i * width;
 293         }
 294
 295         return new;
 296 }
 297
 298 static unsigned char **read_raw_frame(struct lbx_image *img, int frame)
 299 {
 300         unsigned long size = img->width * img->height;
 301
 302         assert(img->flags & FLAG_RAW);
 303
 304         if (img->fops->seek(img->f, img->offsets[frame], SEEK_SET)) {
 305                 return NULL;
 306         }
 307
 308         if (img->fops->read(img->framedata[0], size, img->f) != size) {
 309                 if (img->fops->eof(img->f))
 310                         lbx_error_raise(LBX_EEOF);
 311                 return NULL;
 312         }
 313         memset(img->mask[0], 1, size);
 314
 315         if (img->fops->tell(img->f) > img->offsets[frame+1]) {
 316                 lbx_error_raise(LBX_EFORMAT);
 317                 return NULL;
 318         }
 319
 320         return img->framedata;
 321 }
 322
 323 unsigned char **lbximg_getframe(struct lbx_image *img, int frame)
 324 {
 325         if (frame >= img->frames || frame < 0) {
 326                 lbx_error_raise(LBX_ENOENT);
 327                 return NULL;
 328         }
 329
 330         if (!img->framedata) {
 331                 img->framedata = allocframebuffer(img->width, img->height);
 332                 if (!img->framedata)
 333                         return NULL;
 334         }
 335
 336         if (!img->mask) {
 337                 img->mask = allocframebuffer(img->width, img->height);
 338                 if (!img->mask)
 339                         return NULL;
 340         }
 341
 342         if (img->flags & FLAG_RAW)
 343                 return read_raw_frame(img, frame);
 344
 345         if ((img->flags & FLAG_OVERWRITE)
 346              || (img->chunk && !(frame % img->chunk))) {
 347                 /* Clear the slate. */
 348                 img->currentframe = -1;
 349                 memset(img->framedata[0], 0, img->width * img->height);
 350                 memset(img->mask[0],      0, img->width * img->height);
 351         } else {
 352                 /* Start over if we are backtracking. */
 353                 if (img->currentframe > frame) {
 354                         memset(img->mask[0], 0, img->width * img->height);
 355                         img->currentframe = -1;
 356                 }
 357
 358                 /* We must have previous frame decoded to continue. */
 359                 if (frame > img->currentframe + 1) {
 360                         if (!lbximg_getframe(img, frame-1))
 361                                 return NULL;
 362                 }
 363         }
 364
 365         if (img->currentframe != frame) {
 366                 int rc, first = 1;
 367
 368                 if (img->fops->seek(img->f, img->offsets[frame], SEEK_SET)) {
 369                         return NULL;
 370                 }
 371
 372                 do {
 373                         rc = _lbx_drawrow(first, img);
 374                         if (rc == -1)
 375                                 return NULL;
 376                         first = 0;
 377
 378                         if (img->fops->tell(img->f) > img->offsets[frame+1]) {
 379                                 lbx_error_raise(LBX_EFORMAT);
 380                                 return NULL;
 381                         }
 382                 } while (!rc);
 383         }
 384
 385         img->currentframe = frame;
 386         return img->framedata;
 387 }
 388
 389 int
 390 lbximg_loadpalette(void *f, const struct lbx_file_ops *fops,
 391                    struct lbx_colour palette[static 256])
 392 {
 393         unsigned char entry[4];
 394         int i;
 395
 396         for (i = 0; i < 256; i++) {
 397                 if (fops->read(entry, sizeof entry, f) != sizeof entry) {
 398                         if (fops->eof(f))
 399                                 lbx_error_raise(LBX_EEOF);
 400                         return -1;
 401                 }
 402
 403                 if (entry[0] != 1) {
 404                         lbx_error_raise(LBX_EFORMAT);
 405                         return -1;
 406                 }
 407
 408                 palette[i] = (struct lbx_colour) {
 409                         .red    = entry[1] << 2,
 410                         .green  = entry[2] << 2,
 411                         .blue   = entry[3] << 2,
 412                         .active = 1,
 413                 };
 414         }
 415
 416         return 0;
 417 }
 418
 419 int
 420 lbximg_getpalette(struct lbx_image *img, struct lbx_colour palette[static 256])
 421 {
 422         unsigned char entry[4];
 423         unsigned int i;
 424         size_t rc;
 425
 426         /* Do nothing if the image doesn't have embedded palette data. */
 427         if (!(img->flags & FLAG_PALETTE))
 428                 return 0;
 429
 430         if (img->fops->seek(img->f, img->paloff, SEEK_SET)) {
 431                 return -1;
 432         }
 433
 434         for (i = 0; i < img->palcount; i++) {
 435                 rc = img->fops->read(entry, sizeof entry, img->f);
 436                 if (rc < sizeof entry) {
 437                         goto readerr;
 438                 }
 439
 440                 if (entry[0] != 0) {
 441                         lbx_error_raise(LBX_EFORMAT);
 442                         return -1;
 443                 }
 444
 445                 palette[img->palstart + i] = (struct lbx_colour){
 446                         .red    = entry[1] << 2,
 447                         .green  = entry[2] << 2,
 448                         .blue   = entry[3] << 2,
 449                         .active = 1,
 450                 };
 451         }
 452
 453         return 0;
 454 readerr:
 455         if (img->fops->eof(img->f))
 456                 lbx_error_raise(LBX_EEOF);
 457         return -1;
 458 }
 459
 460 void lbximg_getinfo(struct lbx_image *img, struct lbx_imginfo *info)
 461 {
 462         *info = (struct lbx_imginfo) {
 463                 .width      = img->width,
 464                 .height     = img->height,
 465                 .nframes    = img->frames,
 466                 .chunk      = img->chunk,
 467                 .palettesz  = (img->flags & FLAG_PALETTE) ? img->palcount : 0,
 468         };
 469
 470         /* There seems to be two ways of specifying that an image loops. */
 471         if (img->flags & FLAG_LOOPING) {
 472                 info->loopstart = 0;
 473                 info->looping   = 1;
 474         } else if (img->leadin != img->frames - 1) {
 475                 info->loopstart = img->leadin;
 476                 info->looping   = 1;
 477         }
 478 }
 479
 480 unsigned char **lbximg_getmask(struct lbx_image *img)
 481 {
 482         return img->mask;
 483 }
 484
 485 int lbximg_close(struct lbx_image *img)
 486 {
 487         int rc = 0;
 488
 489         if (img) {
 490                 if (img->framedata) {
 491                         free(img->framedata[0]);
 492                         free(img->framedata);
 493                 }
 494
 495                 if (img->mask) {
 496                         free(img->mask[0]);
 497                         free(img->mask);
 498                 }
 499
 500                 if (img && img->dtor) {
 501                         rc = img->dtor(img->f);
 502                 }
 503
 504                 free(img);
 505         }
 506
 507         return rc;
 508 }