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 <inttypes.h>
  24 #include <errno.h>
  25
  26 #include "pack.h"
  27 #include "misc.h"
  28 #include "lbx.h"
  29 #include "error.h"
  30 #include "image.h"
  31
  32 #define FLAG_RAW       0x0100 /* Image is stored as a flat array of bytes. */
  33 #define FLAG_OVERWRITE 0x0400 /* Draw each frame on a clean slate (unsure). */
  34 #define FLAG_BUILDING  0x0800 /* Buildings have this, related to shadow? */
  35 #define FLAG_PALETTE   0x1000 /* Image contains embedded palette. */
  36 #define FLAG_LOOPING   0x2000 /* Loop over all frames in the image (unsure). */
  37
  38 #define FLAG_ALL (FLAG_RAW|FLAG_OVERWRITE|FLAG_BUILDING|FLAG_PALETTE|FLAG_LOOPING)
  39
  40 #define HDR_LEN 12
  41
  42 struct lbx_image_priv {
  43         struct lbx_image pub;
  44
  45         unsigned short wtf, flags;
  46         unsigned char  wtf2, leadin;
  47         unsigned short palstart, palcount;
  48
  49         const struct lbx_file_ops *fops;
  50         int (*dtor)(void *handle);
  51         void *f;
  52
  53         long paloff;
  54
  55         int currentframe;
  56         int currentx, currenty;
  57         unsigned char **framedata;
  58         unsigned char **mask;
  59
  60         unsigned long offsets[];
  61 };
  62
  63 static struct lbx_image_priv *lbx_img_init(unsigned char hdr[static HDR_LEN])
  64 {
  65         unsigned short nframes = unpack_16_le(hdr+6);
  66         struct lbx_image_priv *img;
  67
  68         img = malloc(sizeof *img + sizeof img->offsets[0] * (nframes+1));
  69         if (!img) {
  70                 lbx_error_raise(LBX_ENOMEM);
  71                 return NULL;
  72         }
  73
  74         *img = (struct lbx_image_priv) {
  75                 .pub.width  = unpack_16_le(hdr+0),
  76                 .pub.height = unpack_16_le(hdr+2),
  77                 .wtf        = unpack_16_le(hdr+4),
  78                 .pub.frames = hdr[6],
  79                 .wtf2       = hdr[7],
  80                 .leadin     = hdr[8],
  81                 .pub.chunk  = hdr[9],
  82                 .flags      = unpack_16_le(hdr+10),
  83
  84                 .currentframe = -1,
  85         };
  86
  87         return img;
  88 }
  89
  90 struct lbx_image *lbx_img_open(void *f, const struct lbx_file_ops *fops,
  91                                int (*destructor)(void *))
  92 {
  93         unsigned char hdr_buf[HDR_LEN];
  94         struct lbx_image_priv *img;
  95
  96         if (fops->read(hdr_buf, sizeof hdr_buf, f) != sizeof hdr_buf) {
  97                 if (fops->eof(f))
  98                         lbx_error_raise(LBX_EEOF);
  99                 return NULL;
 100         }
 101
 102         img = lbx_img_init(hdr_buf);
 103         if (!img)
 104                 return NULL;
 105
 106         img->f    = f;
 107         img->fops = fops;
 108         img->dtor = destructor;
 109
 110         /*
 111          * DEBUG ONLY.  These assertions exist to catch otherwise valid image
 112          * files which differ from what I believe to be true of all LBX images.
 113          * When we can decode every image, then these assertions should be
 114          * replaced with constraints.
 115          */
 116         _lbx_assert(img->wtf  == 0); /* version? */
 117         _lbx_assert(img->wtf2 == 0); /* very likely is simply reserved. */
 118         _lbx_assert(img->pub.frames > img->leadin);
 119         _lbx_assert(!(img->flags & ~FLAG_ALL));
 120
 121         /* Read all offsets.  Should be merged with identical code in lbx.c */
 122         for (unsigned i = 0; i <= img->pub.frames; i++) {
 123                 unsigned char buf[4];
 124
 125                 if (fops->read(buf, sizeof buf, f) != sizeof buf) {
 126                         if (fops->eof(f))
 127                                 lbx_error_raise(LBX_EEOF);
 128                         free(img);
 129                         return NULL;
 130                 }
 131
 132                 img->offsets[i] = unpack_32_le(buf);
 133         }
 134
 135         if (img->flags & FLAG_PALETTE) {
 136                 unsigned char buf[4];
 137
 138                 if (fops->read(buf, sizeof buf, f) != sizeof buf) {
 139                         if (fops->eof(f))
 140                                 lbx_error_raise(LBX_EEOF);
 141                         free(img);
 142                         return NULL;
 143                 }
 144
 145                 img->palstart = unpack_16_le(buf+0);
 146                 img->palcount = unpack_16_le(buf+2);
 147                 img->paloff   = fops->tell(f);
 148
 149                 if (img->palstart + img->palcount > 256) {
 150                         lbx_error_raise(LBX_EFORMAT);
 151                         free(img);
 152                         return NULL;
 153                 }
 154         }
 155
 156         return &img->pub;
 157 }
 158
 159 static int pipe_close(void *f)
 160 {
 161         struct lbx_pipe_state *p = f;
 162         int rc;
 163
 164         rc = fclose(p->f);
 165         free(p);
 166         return rc;
 167 }
 168
 169 static int file_close(void *f)
 170 {
 171         return fclose((FILE *)f);
 172 }
 173
 174 struct lbx_image *lbx_img_fopen(const char *file)
 175 {
 176         struct lbx_pipe_state *p;
 177         FILE *f;
 178
 179         f = fopen(file, "rb");
 180         if (!f) {
 181                 lbx_error_raise(-errno);
 182                 return NULL;
 183         }
 184
 185         if (fseek(f, 0, SEEK_CUR) == 0)
 186                 return lbx_img_open(f, &lbx_default_fops, file_close);
 187
 188         p = malloc(sizeof *p);
 189         if (!p) {
 190                 lbx_error_raise(LBX_ENOMEM);
 191                 fclose(f);
 192                 return NULL;
 193         }
 194
 195         *p = (struct lbx_pipe_state) { .f = f };
 196         return lbx_img_open(p, &lbx_pipe_fops, pipe_close);
 197 }
 198
 199 static int _lbx_drawrow(struct lbx_image_priv *img)
 200 {
 201         unsigned short length, offset;
 202         unsigned char buf[4];
 203         unsigned char *pos;
 204         size_t rc;
 205
 206         assert(img->framedata);
 207         assert(img->mask);
 208
 209         if (img->fops->read(buf, sizeof buf, img->f) != sizeof buf)
 210                 goto readerr;
 211
 212         length = unpack_16_le(buf+0);
 213         offset = unpack_16_le(buf+2);
 214         if (length == 0 && offset == 1000)
 215                 return 1;
 216
 217         /* Length of 0 increments Y position */
 218         if (!length) {
 219                 if (offset > img->pub.height - img->currenty) {
 220                         lbx_error_raise(LBX_EFORMAT);
 221                         return -1;
 222                 }
 223
 224                 img->currenty += offset;
 225                 img->currentx  = 0;
 226                 return 0;
 227         }
 228
 229         /* Otherwise we read pixel data */
 230         if (offset > img->pub.width - img->currentx) {
 231                 lbx_error_raise(LBX_EFORMAT);
 232                 return -1;
 233         }
 234         img->currentx += offset;
 235
 236         if (length > img->pub.width - img->currentx) {
 237                 lbx_error_raise(LBX_EFORMAT);
 238                 return -1;
 239         }
 240
 241         memset(&img->mask[img->currenty][img->currentx], 1, length);
 242
 243         pos = &img->framedata[img->currenty][img->currentx];
 244         rc  = img->fops->read(pos, length, img->f);
 245         img->currentx += rc;
 246
 247         if (rc < length)
 248                 goto readerr;
 249
 250         /* Skip padding byte, if any */
 251         if (length % 2) {
 252                 if (img->fops->read(buf, 1, img->f) != 1)
 253                         goto readerr;
 254         }
 255
 256         return 0;
 257 readerr:
 258         if (img->fops->eof(img->f))
 259                 lbx_error_raise(LBX_EEOF);
 260         return -1;
 261 }
 262
 263 static unsigned char **allocframebuffer(size_t width, size_t height)
 264 {
 265         unsigned char **new, *tmp;
 266         size_t i;
 267
 268         if (height > SIZE_MAX / sizeof *new) {
 269                 lbx_error_raise(LBX_ENOMEM);
 270                 return NULL;
 271         }
 272
 273         /* Ensure that there is at least one row in the framebuffer. */
 274         if (height == 0 || width == 0)
 275                 width = height = 1;
 276
 277         tmp = calloc(height, width);
 278         if (!tmp) {
 279                 lbx_error_raise(LBX_ENOMEM);
 280                 return NULL;
 281         }
 282
 283         new = malloc(height * sizeof *new);
 284         if (!new) {
 285                 lbx_error_raise(LBX_ENOMEM);
 286                 free(tmp);
 287                 return NULL;
 288         }
 289
 290         for (i = 0; i < height; i++) {
 291                 new[i] = tmp + i * width;
 292         }
 293
 294         return new;
 295 }
 296
 297 static unsigned char **read_raw_frame(struct lbx_image_priv *img, int frame)
 298 {
 299         unsigned long size = img->pub.width * img->pub.height;
 300
 301         assert(img->flags & FLAG_RAW);
 302
 303         if (img->fops->seek(img->f, img->offsets[frame], SEEK_SET)) {
 304                 return NULL;
 305         }
 306
 307         if (img->fops->read(img->framedata[0], size, img->f) != size) {
 308                 if (img->fops->eof(img->f))
 309                         lbx_error_raise(LBX_EEOF);
 310                 return NULL;
 311         }
 312         memset(img->mask[0], 1, size);
 313
 314         if (img->fops->tell(img->f) > img->offsets[frame+1]) {
 315                 lbx_error_raise(LBX_EFORMAT);
 316                 return NULL;
 317         }
 318
 319         return img->framedata;
 320 }
 321
 322 unsigned char **lbx_img_getframe(struct lbx_image *pub, int frame)
 323 {
 324         struct lbx_image_priv *img = (struct lbx_image_priv *)pub;
 325         unsigned char buf[4];
 326
 327         if (frame >= pub->frames || frame < 0) {
 328                 lbx_error_raise(LBX_ENOENT);
 329                 return NULL;
 330         }
 331
 332         if (!img->framedata) {
 333                 img->framedata = allocframebuffer(pub->width, pub->height);
 334                 if (!img->framedata)
 335                         return NULL;
 336         }
 337
 338         if (!img->mask) {
 339                 img->mask = allocframebuffer(pub->width, pub->height);
 340                 if (!img->mask)
 341                         return NULL;
 342         }
 343
 344         if (img->flags & FLAG_RAW)
 345                 return read_raw_frame(img, frame);
 346
 347         if ((img->flags & FLAG_OVERWRITE)
 348              || (pub->chunk && !(frame % pub->chunk))) {
 349                 /* Clear the slate. */
 350                 img->currentframe = -1;
 351                 memset(img->framedata[0], 0, pub->width * pub->height);
 352                 memset(img->mask[0],      0, pub->width * pub->height);
 353         } else {
 354                 /* Start over if we are backtracking. */
 355                 if (img->currentframe > frame) {
 356                         memset(img->mask[0], 0, pub->width * pub->height);
 357                         img->currentframe = -1;
 358                 }
 359
 360                 /* We must have previous frame decoded to continue. */
 361                 if (frame > img->currentframe + 1) {
 362                         if (!lbx_img_getframe(pub, frame-1))
 363                                 return NULL;
 364                 }
 365         }
 366
 367         if (img->currentframe != frame) {
 368                 int rc;
 369
 370                 if (img->fops->seek(img->f, img->offsets[frame], SEEK_SET)) {
 371                         return NULL;
 372                 }
 373
 374                 /* Read frame header */
 375                 if (img->fops->read(buf, 4, img->f) != 4) {
 376                         if (img->fops->eof(img->f))
 377                                 lbx_error_raise(LBX_EEOF);
 378                         return NULL;
 379                 }
 380
 381                 if (unpack_16_le(buf) != 1) {
 382                         lbx_error_raise(LBX_EFORMAT);
 383                         return NULL;
 384                 }
 385
 386                 img->currentx = 0;
 387                 img->currenty = unpack_16_le(buf+2);
 388                 if (img->currenty > img->pub.height) {
 389                         lbx_error_raise(LBX_EFORMAT);
 390                         return NULL;
 391                 }
 392
 393                 do {
 394                         rc = _lbx_drawrow(img);
 395                         if (rc == -1)
 396                                 return NULL;
 397
 398                         if (img->fops->tell(img->f) > img->offsets[frame+1]) {
 399                                 lbx_error_raise(LBX_EFORMAT);
 400                                 return NULL;
 401                         }
 402                 } while (!rc);
 403         }
 404
 405         img->currentframe = frame;
 406         return img->framedata;
 407 }
 408
 409 int
 410 lbx_img_loadpalette(void *f, const struct lbx_file_ops *fops,
 411                     struct lbx_colour palette[static 256])
 412 {
 413         unsigned char entry[4];
 414         int i;
 415
 416         for (i = 0; i < 256; i++) {
 417                 if (fops->read(entry, sizeof entry, f) != sizeof entry) {
 418                         if (fops->eof(f))
 419                                 lbx_error_raise(LBX_EEOF);
 420                         return -1;
 421                 }
 422
 423                 if (entry[0] != 1) {
 424                         lbx_error_raise(LBX_EFORMAT);
 425                         return -1;
 426                 }
 427
 428                 palette[i] = (struct lbx_colour) {
 429                         .red    = entry[1] & 0x3f,
 430                         .green  = entry[2] & 0x3f,
 431                         .blue   = entry[3] & 0x3f,
 432                         .active = 1,
 433                 };
 434         }
 435
 436         return 0;
 437 }
 438
 439 int
 440 lbx_img_getpalette(struct lbx_image *pub, struct lbx_colour palette[static 256])
 441 {
 442         struct lbx_image_priv *img = (struct lbx_image_priv *)pub;
 443         unsigned char entry[4];
 444         unsigned int i;
 445         size_t rc;
 446
 447         /* Do nothing if the image doesn't have embedded palette data. */
 448         if (!(img->flags & FLAG_PALETTE))
 449                 return 0;
 450
 451         if (img->fops->seek(img->f, img->paloff, SEEK_SET)) {
 452                 return -1;
 453         }
 454
 455         for (i = 0; i < img->palcount; i++) {
 456                 rc = img->fops->read(entry, sizeof entry, img->f);
 457                 if (rc < sizeof entry) {
 458                         goto readerr;
 459                 }
 460
 461                 if (entry[0] != 0) {
 462                         lbx_error_raise(LBX_EFORMAT);
 463                         return -1;
 464                 }
 465
 466                 palette[img->palstart + i] = (struct lbx_colour){
 467                         .red    = entry[1],
 468                         .green  = entry[2],
 469                         .blue   = entry[3],
 470                         .active = 1,
 471                 };
 472         }
 473
 474         return 0;
 475 readerr:
 476         if (img->fops->eof(img->f))
 477                 lbx_error_raise(LBX_EEOF);
 478         return -1;
 479 }
 480
 481 void lbx_img_getinfo(struct lbx_image *pub, struct lbx_imginfo *info)
 482 {
 483         struct lbx_image_priv *img = (struct lbx_image_priv *)pub;
 484
 485         *info = (struct lbx_imginfo) {
 486                 .palettesz  = (img->flags & FLAG_PALETTE) ? img->palcount : 0,
 487         };
 488
 489         /* There seems to be two ways of specifying that an image loops. */
 490         if (img->flags & FLAG_LOOPING) {
 491                 info->loopstart = 0;
 492                 info->looping   = 1;
 493         } else if (img->leadin != pub->frames - 1) {
 494                 info->loopstart = img->leadin;
 495                 info->looping   = 1;
 496         }
 497 }
 498
 499 unsigned char **lbx_img_getmask(struct lbx_image *pub)
 500 {
 501         struct lbx_image_priv *img = (struct lbx_image_priv *)pub;
 502
 503         return img->mask;
 504 }
 505
 506 int lbx_img_close(struct lbx_image *pub)
 507 {
 508         struct lbx_image_priv *img = (struct lbx_image_priv *)pub;
 509         int rc = 0;
 510
 511         if (img) {
 512                 if (img->framedata) {
 513                         free(img->framedata[0]);
 514                         free(img->framedata);
 515                 }
 516
 517                 if (img->mask) {
 518                         free(img->mask[0]);
 519                         free(img->mask);
 520                 }
 521
 522                 if (img && img->dtor) {
 523                         rc = img->dtor(img->f);
 524                 }
 525
 526                 free(img);
 527         }
 528
 529         return rc;
 530 }