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, 2013-2014 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;
  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                 .pub.leadin = hdr[8],
  81                 .pub.chunk  = hdr[9],
  82                 .flags      = unpack_16_le(hdr+10),
  83
  84                 .currentframe = -1,
  85         };
  86
  87         if (img->flags & FLAG_OVERWRITE)
  88                 img->pub.chunk = 1;
  89
  90         if (img->flags & FLAG_LOOPING)
  91                 img->pub.leadin = 0;
  92
  93         return img;
  94 }
  95
  96 struct lbx_image *lbx_img_open(void *f, const struct lbx_file_ops *fops,
  97                                int (*destructor)(void *))
  98 {
  99         unsigned char hdr_buf[HDR_LEN];
 100         struct lbx_image_priv *img;
 101
 102         if (fops->read(hdr_buf, sizeof hdr_buf, f) != sizeof hdr_buf) {
 103                 if (fops->eof(f))
 104                         lbx_error_raise(LBX_EEOF);
 105                 return NULL;
 106         }
 107
 108         img = lbx_img_init(hdr_buf);
 109         if (!img)
 110                 return NULL;
 111
 112         img->f    = f;
 113         img->fops = fops;
 114         img->dtor = destructor;
 115
 116         /*
 117          * DEBUG ONLY.  These assertions exist to catch otherwise valid image
 118          * files which differ from what I believe to be true of all LBX images.
 119          * When we can decode every image, then these assertions should be
 120          * replaced with constraints.
 121          */
 122         _lbx_assert(img->wtf  == 0); /* version? */
 123         _lbx_assert(img->wtf2 == 0); /* very likely is simply reserved. */
 124         _lbx_assert(img->pub.frames > img->pub.leadin);
 125         _lbx_assert(!(img->flags & ~FLAG_ALL));
 126
 127         /* Read all offsets.  Should be merged with identical code in lbx.c */
 128         for (unsigned i = 0; i <= img->pub.frames; i++) {
 129                 unsigned char buf[4];
 130
 131                 if (fops->read(buf, sizeof buf, f) != sizeof buf) {
 132                         if (fops->eof(f))
 133                                 lbx_error_raise(LBX_EEOF);
 134                         free(img);
 135                         return NULL;
 136                 }
 137
 138                 img->offsets[i] = unpack_32_le(buf);
 139         }
 140
 141         if (img->flags & FLAG_PALETTE) {
 142                 unsigned char buf[4];
 143
 144                 if (fops->read(buf, sizeof buf, f) != sizeof buf) {
 145                         if (fops->eof(f))
 146                                 lbx_error_raise(LBX_EEOF);
 147                         free(img);
 148                         return NULL;
 149                 }
 150
 151                 img->palstart = unpack_16_le(buf+0);
 152                 img->palcount = unpack_16_le(buf+2);
 153                 img->paloff   = fops->tell(f);
 154
 155                 if (img->palstart + img->palcount > 256) {
 156                         lbx_error_raise(LBX_EFORMAT);
 157                         free(img);
 158                         return NULL;
 159                 }
 160         }
 161
 162         return &img->pub;
 163 }
 164
 165 static int pipe_close(void *f)
 166 {
 167         struct lbx_pipe_state *p = f;
 168         int rc;
 169
 170         rc = fclose(p->f);
 171         free(p);
 172         return rc;
 173 }
 174
 175 static int file_close(void *f)
 176 {
 177         return fclose((FILE *)f);
 178 }
 179
 180 struct lbx_image *lbx_img_fopen(const char *file)
 181 {
 182         struct lbx_pipe_state *p;
 183         FILE *f;
 184
 185         f = fopen(file, "rb");
 186         if (!f) {
 187                 lbx_error_raise(-errno);
 188                 return NULL;
 189         }
 190
 191         if (fseek(f, 0, SEEK_CUR) == 0)
 192                 return lbx_img_open(f, &lbx_default_fops, file_close);
 193
 194         p = malloc(sizeof *p);
 195         if (!p) {
 196                 lbx_error_raise(LBX_ENOMEM);
 197                 fclose(f);
 198                 return NULL;
 199         }
 200
 201         *p = (struct lbx_pipe_state) { .f = f };
 202         return lbx_img_open(p, &lbx_pipe_fops, pipe_close);
 203 }
 204
 205 static int _lbx_drawrow(struct lbx_image_priv *img)
 206 {
 207         unsigned short length, offset;
 208         unsigned char buf[4];
 209         unsigned char *pos;
 210         size_t rc;
 211
 212         assert(img->framedata);
 213         assert(img->mask);
 214
 215         if (img->fops->read(buf, sizeof buf, img->f) != sizeof buf)
 216                 goto readerr;
 217
 218         length = unpack_16_le(buf+0);
 219         offset = unpack_16_le(buf+2);
 220         if (length == 0 && offset == 1000)
 221                 return 1;
 222
 223         /* Length of 0 increments Y position */
 224         if (!length) {
 225                 if (offset > img->pub.height - img->currenty) {
 226                         lbx_error_raise(LBX_EFORMAT);
 227                         return -1;
 228                 }
 229
 230                 img->currenty += offset;
 231                 img->currentx  = 0;
 232                 return 0;
 233         }
 234
 235         /* Otherwise we read pixel data */
 236         if (offset > img->pub.width - img->currentx) {
 237                 lbx_error_raise(LBX_EFORMAT);
 238                 return -1;
 239         }
 240         img->currentx += offset;
 241
 242         if (length > img->pub.width - img->currentx) {
 243                 lbx_error_raise(LBX_EFORMAT);
 244                 return -1;
 245         }
 246
 247         memset(&img->mask[img->currenty][img->currentx], 1, length);
 248
 249         pos = &img->framedata[img->currenty][img->currentx];
 250         rc  = img->fops->read(pos, length, img->f);
 251         img->currentx += rc;
 252
 253         if (rc < length)
 254                 goto readerr;
 255
 256         /* Skip padding byte, if any */
 257         if (length % 2) {
 258                 if (img->fops->read(buf, 1, img->f) != 1)
 259                         goto readerr;
 260         }
 261
 262         return 0;
 263 readerr:
 264         if (img->fops->eof(img->f))
 265                 lbx_error_raise(LBX_EEOF);
 266         return -1;
 267 }
 268
 269 static unsigned char **allocframebuffer(size_t width, size_t height)
 270 {
 271         unsigned char **new, *tmp;
 272         size_t i;
 273
 274         if (height > SIZE_MAX / sizeof *new) {
 275                 lbx_error_raise(LBX_ENOMEM);
 276                 return NULL;
 277         }
 278
 279         /* Ensure that there is at least one row in the framebuffer. */
 280         if (height == 0 || width == 0)
 281                 width = height = 1;
 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         unsigned char buf[4];
 332
 333         if (frame >= pub->frames || frame < 0) {
 334                 lbx_error_raise(LBX_EINVAL);
 335                 return NULL;
 336         }
 337
 338         if (!img->framedata) {
 339                 img->framedata = allocframebuffer(pub->width, pub->height);
 340                 if (!img->framedata)
 341                         return NULL;
 342         }
 343
 344         if (!img->mask) {
 345                 img->mask = allocframebuffer(pub->width, pub->height);
 346                 if (!img->mask)
 347                         return NULL;
 348         }
 349
 350         if (img->flags & FLAG_RAW)
 351                 return read_raw_frame(img, frame);
 352
 353         if ((img->flags & FLAG_OVERWRITE)
 354              || (pub->chunk && !(frame % pub->chunk))) {
 355                 /* Clear the slate. */
 356                 img->currentframe = -1;
 357                 memset(img->framedata[0], 0, pub->width * pub->height);
 358                 memset(img->mask[0],      0, pub->width * pub->height);
 359         } else {
 360                 /* Start over if we are backtracking. */
 361                 if (img->currentframe > frame) {
 362                         memset(img->mask[0], 0, pub->width * pub->height);
 363                         img->currentframe = -1;
 364                 }
 365
 366                 /* We must have previous frame decoded to continue. */
 367                 if (frame > img->currentframe + 1) {
 368                         if (!lbx_img_getframe(pub, frame-1))
 369                                 return NULL;
 370                 }
 371         }
 372
 373         if (img->currentframe != frame) {
 374                 int rc;
 375
 376                 if (img->fops->seek(img->f, img->offsets[frame], SEEK_SET)) {
 377                         return NULL;
 378                 }
 379
 380                 /* Read frame header */
 381                 if (img->fops->read(buf, 4, img->f) != 4) {
 382                         if (img->fops->eof(img->f))
 383                                 lbx_error_raise(LBX_EEOF);
 384                         return NULL;
 385                 }
 386
 387                 if (unpack_16_le(buf) != 1) {
 388                         lbx_error_raise(LBX_EFORMAT);
 389                         return NULL;
 390                 }
 391
 392                 img->currentx = 0;
 393                 img->currenty = unpack_16_le(buf+2);
 394                 if (img->currenty > img->pub.height) {
 395                         lbx_error_raise(LBX_EFORMAT);
 396                         return NULL;
 397                 }
 398
 399                 do {
 400                         rc = _lbx_drawrow(img);
 401                         if (rc == -1)
 402                                 return NULL;
 403
 404                         if (img->fops->tell(img->f) > img->offsets[frame+1]) {
 405                                 lbx_error_raise(LBX_EFORMAT);
 406                                 return NULL;
 407                         }
 408                 } while (!rc);
 409         }
 410
 411         img->currentframe = frame;
 412         return img->framedata;
 413 }
 414
 415 int
 416 lbx_img_loadpalette(void *f, const struct lbx_file_ops *fops,
 417                     struct lbx_colour palette[static 256])
 418 {
 419         unsigned char entry[4];
 420         int i;
 421
 422         for (i = 0; i < 256; i++) {
 423                 if (fops->read(entry, sizeof entry, f) != sizeof entry) {
 424                         if (fops->eof(f))
 425                                 lbx_error_raise(LBX_EEOF);
 426                         return -1;
 427                 }
 428
 429                 if (entry[0] != 1) {
 430                         lbx_error_raise(LBX_EFORMAT);
 431                         return -1;
 432                 }
 433
 434                 palette[i] = (struct lbx_colour) {
 435                         .red    = entry[1] & 0x3f,
 436                         .green  = entry[2] & 0x3f,
 437                         .blue   = entry[3] & 0x3f,
 438                         .active = 1,
 439                 };
 440         }
 441
 442         return 0;
 443 }
 444
 445 int
 446 lbx_img_getpalette(struct lbx_image *pub, struct lbx_colour palette[static 256])
 447 {
 448         struct lbx_image_priv *img = (struct lbx_image_priv *)pub;
 449         unsigned char entry[4];
 450         unsigned int i;
 451         size_t rc;
 452
 453         /* Do nothing if the image doesn't have embedded palette data. */
 454         if (!(img->flags & FLAG_PALETTE))
 455                 return 0;
 456
 457         if (img->fops->seek(img->f, img->paloff, SEEK_SET)) {
 458                 return -1;
 459         }
 460
 461         for (i = 0; i < img->palcount; i++) {
 462                 rc = img->fops->read(entry, sizeof entry, img->f);
 463                 if (rc < sizeof entry) {
 464                         goto readerr;
 465                 }
 466
 467                 if (entry[0] != 0) {
 468                         lbx_error_raise(LBX_EFORMAT);
 469                         return -1;
 470                 }
 471
 472                 palette[img->palstart + i] = (struct lbx_colour){
 473                         .red    = entry[1],
 474                         .green  = entry[2],
 475                         .blue   = entry[3],
 476                         .active = 1,
 477                 };
 478         }
 479
 480         return 0;
 481 readerr:
 482         if (img->fops->eof(img->f))
 483                 lbx_error_raise(LBX_EEOF);
 484         return -1;
 485 }
 486
 487 void lbx_img_getinfo(struct lbx_image *pub, struct lbx_imginfo *info)
 488 {
 489         struct lbx_image_priv *img = (struct lbx_image_priv *)pub;
 490
 491         *info = (struct lbx_imginfo) {
 492                 .palettesz  = (img->flags & FLAG_PALETTE) ? img->palcount : 0,
 493         };
 494
 495         /* There seems to be two ways of specifying that an image loops. */
 496         if (img->flags & FLAG_LOOPING) {
 497                 info->loopstart = 0;
 498                 info->looping   = 1;
 499         } else if (img->pub.leadin != pub->frames - 1) {
 500                 info->loopstart = img->pub.leadin;
 501                 info->looping   = 1;
 502         }
 503 }
 504
 505 unsigned char **lbx_img_getmask(struct lbx_image *pub)
 506 {
 507         struct lbx_image_priv *img = (struct lbx_image_priv *)pub;
 508
 509         return img->mask;
 510 }
 511
 512 int lbx_img_close(struct lbx_image *pub)
 513 {
 514         struct lbx_image_priv *img = (struct lbx_image_priv *)pub;
 515         int rc = 0;
 516
 517         if (img) {
 518                 if (img->framedata) {
 519                         free(img->framedata[0]);
 520                         free(img->framedata);
 521                 }
 522
 523                 if (img->mask) {
 524                         free(img->mask[0]);
 525                         free(img->mask);
 526                 }
 527
 528                 if (img && img->dtor) {
 529                         rc = img->dtor(img->f);
 530                 }
 531
 532                 free(img);
 533         }
 534
 535         return rc;
 536 }