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 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                 return NULL;
 181
 182         if (fseek(f, 0, SEEK_CUR) == 0)
 183                 return lbx_img_open(f, &lbx_default_fops, file_close);
 184
 185         p = malloc(sizeof *p);
 186         if (!p) {
 187                 fclose(f);
 188                 return NULL;
 189         }
 190
 191         *p = (struct lbx_pipe_state) { .f = f };
 192         return lbx_img_open(p, &lbx_pipe_fops, pipe_close);
 193 }
 194
 195 static int _lbx_drawrow(int first, struct lbx_image_priv *img)
 196 {
 197         unsigned short type, count, yval, xval;
 198         unsigned char buf[4];
 199         unsigned char *pos;
 200         size_t rc;
 201
 202         assert(img->framedata);
 203         assert(img->mask);
 204
 205         if (img->fops->read(buf, sizeof buf, img->f) != sizeof buf)
 206                 goto readerr;
 207         type = unpack_16_le(buf+0);
 208
 209         if (first) {
 210                 img->currentx = 0;
 211                 img->currenty = 0;
 212                 type = 0;
 213         }
 214
 215         if (type == 0) {
 216                 yval = unpack_16_le(buf+2);
 217                 if (yval == 1000)
 218                         return 1;
 219
 220                 if (img->fops->read(buf, sizeof buf, img->f) != sizeof buf)
 221                         goto readerr;
 222                 count = unpack_16_le(buf+0);
 223
 224                 xval = unpack_16_le(buf+2);
 225                 if (xval == 1000)
 226                         return 1;
 227
 228                 /* Ensure that the row fits in the image. */
 229                 if (img->pub.height - img->currenty <= yval
 230                     || xval >= img->pub.width) {
 231                         lbx_error_raise(LBX_EFORMAT);
 232                         return -1;
 233                 }
 234
 235                 img->currenty += yval;
 236                 img->currentx  = xval;
 237         } else {
 238                 xval = unpack_16_le(buf+2);
 239
 240                 if (img->pub.width - img->currentx <= xval) {
 241                         lbx_error_raise(LBX_EFORMAT);
 242                         return -1;
 243                 }
 244                 img->currentx += xval;
 245
 246                 count = type;
 247         }
 248
 249         if (count > img->pub.width - img->currentx) {
 250                 lbx_error_raise(LBX_EFORMAT);
 251                 return -1;
 252         }
 253
 254         memset(&img->mask[img->currenty][img->currentx], 1, count);
 255
 256         pos = &img->framedata[img->currenty][img->currentx];
 257         rc  = img->fops->read(pos, count, img->f);
 258         img->currentx += rc;
 259
 260         if (rc < count)
 261                 goto readerr;
 262
 263         if (count % 2) {
 264                 if (img->fops->read(buf, 1, img->f) != 1)
 265                         goto readerr;
 266         }
 267
 268         return 0;
 269 readerr:
 270         if (img->fops->eof(img->f))
 271                 lbx_error_raise(LBX_EEOF);
 272         return -1;
 273 }
 274
 275 static unsigned char **allocframebuffer(size_t width, size_t height)
 276 {
 277         unsigned char **new, *tmp;
 278         size_t i;
 279
 280         tmp = calloc(height, width);
 281         if (!tmp) {
 282                 lbx_error_raise(LBX_ENOMEM);
 283                 return NULL;
 284         }
 285
 286         new = malloc(height * sizeof *new);
 287         if (!new) {
 288                 lbx_error_raise(LBX_ENOMEM);
 289                 free(tmp);
 290                 return NULL;
 291         }
 292
 293         for (i = 0; i < height; i++) {
 294                 new[i] = tmp + i * width;
 295         }
 296
 297         return new;
 298 }
 299
 300 static unsigned char **read_raw_frame(struct lbx_image_priv *img, int frame)
 301 {
 302         unsigned long size = img->pub.width * img->pub.height;
 303
 304         assert(img->flags & FLAG_RAW);
 305
 306         if (img->fops->seek(img->f, img->offsets[frame], SEEK_SET)) {
 307                 return NULL;
 308         }
 309
 310         if (img->fops->read(img->framedata[0], size, img->f) != size) {
 311                 if (img->fops->eof(img->f))
 312                         lbx_error_raise(LBX_EEOF);
 313                 return NULL;
 314         }
 315         memset(img->mask[0], 1, size);
 316
 317         if (img->fops->tell(img->f) > img->offsets[frame+1]) {
 318                 lbx_error_raise(LBX_EFORMAT);
 319                 return NULL;
 320         }
 321
 322         return img->framedata;
 323 }
 324
 325 unsigned char **lbx_img_getframe(struct lbx_image *pub, int frame)
 326 {
 327         struct lbx_image_priv *img = (struct lbx_image_priv *)pub;
 328
 329         if (frame >= pub->frames || frame < 0) {
 330                 lbx_error_raise(LBX_ENOENT);
 331                 return NULL;
 332         }
 333
 334         if (!img->framedata) {
 335                 img->framedata = allocframebuffer(pub->width, pub->height);
 336                 if (!img->framedata)
 337                         return NULL;
 338         }
 339
 340         if (!img->mask) {
 341                 img->mask = allocframebuffer(pub->width, pub->height);
 342                 if (!img->mask)
 343                         return NULL;
 344         }
 345
 346         if (img->flags & FLAG_RAW)
 347                 return read_raw_frame(img, frame);
 348
 349         if ((img->flags & FLAG_OVERWRITE)
 350              || (pub->chunk && !(frame % pub->chunk))) {
 351                 /* Clear the slate. */
 352                 img->currentframe = -1;
 353                 memset(img->framedata[0], 0, pub->width * pub->height);
 354                 memset(img->mask[0],      0, pub->width * pub->height);
 355         } else {
 356                 /* Start over if we are backtracking. */
 357                 if (img->currentframe > frame) {
 358                         memset(img->mask[0], 0, pub->width * pub->height);
 359                         img->currentframe = -1;
 360                 }
 361
 362                 /* We must have previous frame decoded to continue. */
 363                 if (frame > img->currentframe + 1) {
 364                         if (!lbx_img_getframe(pub, frame-1))
 365                                 return NULL;
 366                 }
 367         }
 368
 369         if (img->currentframe != frame) {
 370                 int rc, first = 1;
 371
 372                 if (img->fops->seek(img->f, img->offsets[frame], SEEK_SET)) {
 373                         return NULL;
 374                 }
 375
 376                 do {
 377                         rc = _lbx_drawrow(first, img);
 378                         if (rc == -1)
 379                                 return NULL;
 380                         first = 0;
 381
 382                         if (img->fops->tell(img->f) > img->offsets[frame+1]) {
 383                                 lbx_error_raise(LBX_EFORMAT);
 384                                 return NULL;
 385                         }
 386                 } while (!rc);
 387         }
 388
 389         img->currentframe = frame;
 390         return img->framedata;
 391 }
 392
 393 int
 394 lbx_img_loadpalette(void *f, const struct lbx_file_ops *fops,
 395                     struct lbx_colour palette[static 256])
 396 {
 397         unsigned char entry[4];
 398         int i;
 399
 400         for (i = 0; i < 256; i++) {
 401                 if (fops->read(entry, sizeof entry, f) != sizeof entry) {
 402                         if (fops->eof(f))
 403                                 lbx_error_raise(LBX_EEOF);
 404                         return -1;
 405                 }
 406
 407                 if (entry[0] != 1) {
 408                         lbx_error_raise(LBX_EFORMAT);
 409                         return -1;
 410                 }
 411
 412                 palette[i] = (struct lbx_colour) {
 413                         .red    = entry[1] << 2,
 414                         .green  = entry[2] << 2,
 415                         .blue   = entry[3] << 2,
 416                         .active = 1,
 417                 };
 418         }
 419
 420         return 0;
 421 }
 422
 423 int
 424 lbx_img_getpalette(struct lbx_image *pub, struct lbx_colour palette[static 256])
 425 {
 426         struct lbx_image_priv *img = (struct lbx_image_priv *)pub;
 427         unsigned char entry[4];
 428         unsigned int i;
 429         size_t rc;
 430
 431         /* Do nothing if the image doesn't have embedded palette data. */
 432         if (!(img->flags & FLAG_PALETTE))
 433                 return 0;
 434
 435         if (img->fops->seek(img->f, img->paloff, SEEK_SET)) {
 436                 return -1;
 437         }
 438
 439         for (i = 0; i < img->palcount; i++) {
 440                 rc = img->fops->read(entry, sizeof entry, img->f);
 441                 if (rc < sizeof entry) {
 442                         goto readerr;
 443                 }
 444
 445                 if (entry[0] != 0) {
 446                         lbx_error_raise(LBX_EFORMAT);
 447                         return -1;
 448                 }
 449
 450                 palette[img->palstart + i] = (struct lbx_colour){
 451                         .red    = entry[1] << 2,
 452                         .green  = entry[2] << 2,
 453                         .blue   = entry[3] << 2,
 454                         .active = 1,
 455                 };
 456         }
 457
 458         return 0;
 459 readerr:
 460         if (img->fops->eof(img->f))
 461                 lbx_error_raise(LBX_EEOF);
 462         return -1;
 463 }
 464
 465 void lbx_img_getinfo(struct lbx_image *pub, struct lbx_imginfo *info)
 466 {
 467         struct lbx_image_priv *img = (struct lbx_image_priv *)pub;
 468
 469         *info = (struct lbx_imginfo) {
 470                 .palettesz  = (img->flags & FLAG_PALETTE) ? img->palcount : 0,
 471         };
 472
 473         /* There seems to be two ways of specifying that an image loops. */
 474         if (img->flags & FLAG_LOOPING) {
 475                 info->loopstart = 0;
 476                 info->looping   = 1;
 477         } else if (img->leadin != pub->frames - 1) {
 478                 info->loopstart = img->leadin;
 479                 info->looping   = 1;
 480         }
 481 }
 482
 483 unsigned char **lbx_img_getmask(struct lbx_image *pub)
 484 {
 485         struct lbx_image_priv *img = (struct lbx_image_priv *)pub;
 486
 487         return img->mask;
 488 }
 489
 490 int lbx_img_close(struct lbx_image *pub)
 491 {
 492         struct lbx_image_priv *img = (struct lbx_image_priv *)pub;
 493         int rc = 0;
 494
 495         if (img) {
 496                 if (img->framedata) {
 497                         free(img->framedata[0]);
 498                         free(img->framedata);
 499                 }
 500
 501                 if (img->mask) {
 502                         free(img->mask[0]);
 503                         free(img->mask);
 504                 }
 505
 506                 if (img && img->dtor) {
 507                         rc = img->dtor(img->f);
 508                 }
 509
 510                 free(img);
 511         }
 512
 513         return rc;
 514 }