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 /* States for image readout */
  43 enum {
  44         READ_STATE_INIT,
  45         READ_STATE_HEADER,
  46         READ_STATE_DATA,
  47         READ_STATE_DONE,
  48 };
  49
  50 struct lbx_image_priv {
  51         struct lbx_image pub;
  52
  53         unsigned short wtf, flags;
  54         unsigned char  wtf2;
  55         unsigned short palstart, palcount;
  56
  57         const struct lbx_file_ops *fops;
  58         int (*dtor)(void *handle);
  59         void *f;
  60
  61         long paloff;
  62
  63         /* State of frame readout */
  64         unsigned currentx, currenty, currentn;
  65         int read_state;
  66
  67         unsigned long offsets[];
  68 };
  69
  70 static struct lbx_image_priv *lbx_img_init(unsigned char hdr[static HDR_LEN])
  71 {
  72         unsigned short nframes = unpack_16_le(hdr+6);
  73         struct lbx_image_priv *img;
  74
  75         img = malloc(sizeof *img + sizeof img->offsets[0] * (nframes+1));
  76         if (!img) {
  77                 lbx_error_raise(LBX_ENOMEM);
  78                 return NULL;
  79         }
  80
  81         *img = (struct lbx_image_priv) {
  82                 .pub.width  = unpack_16_le(hdr+0),
  83                 .pub.height = unpack_16_le(hdr+2),
  84                 .wtf        = unpack_16_le(hdr+4),
  85                 .pub.frames = hdr[6],
  86                 .wtf2       = hdr[7],
  87                 .pub.leadin = hdr[8],
  88                 .pub.chunk  = hdr[9],
  89                 .flags      = unpack_16_le(hdr+10),
  90         };
  91
  92         if (img->flags & FLAG_OVERWRITE)
  93                 img->pub.chunk = 1;
  94
  95         if (img->flags & FLAG_LOOPING)
  96                 img->pub.leadin = 0;
  97
  98         return img;
  99 }
 100
 101 struct lbx_image *lbx_img_open(void *f, const struct lbx_file_ops *fops,
 102                                int (*destructor)(void *))
 103 {
 104         unsigned char hdr_buf[HDR_LEN];
 105         struct lbx_image_priv *img;
 106
 107         if (fops->read(hdr_buf, sizeof hdr_buf, f) != sizeof hdr_buf) {
 108                 if (fops->eof(f))
 109                         lbx_error_raise(LBX_EEOF);
 110                 return NULL;
 111         }
 112
 113         img = lbx_img_init(hdr_buf);
 114         if (!img)
 115                 return NULL;
 116
 117         img->f    = f;
 118         img->fops = fops;
 119         img->dtor = destructor;
 120
 121         /*
 122          * DEBUG ONLY.  These assertions exist to catch otherwise valid image
 123          * files which differ from what I believe to be true of all LBX images.
 124          * When we can decode every image, then these assertions should be
 125          * replaced with constraints.
 126          */
 127         _lbx_assert(img->wtf  == 0); /* version? */
 128         _lbx_assert(img->wtf2 == 0); /* very likely is simply reserved. */
 129         _lbx_assert(img->pub.frames > img->pub.leadin);
 130         _lbx_assert(!(img->flags & ~FLAG_ALL));
 131
 132         /* Read all offsets.  Should be merged with identical code in lbx.c */
 133         for (unsigned i = 0; i <= img->pub.frames; i++) {
 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->offsets[i] = unpack_32_le(buf);
 144         }
 145
 146         if (img->flags & FLAG_PALETTE) {
 147                 unsigned char buf[4];
 148
 149                 if (fops->read(buf, sizeof buf, f) != sizeof buf) {
 150                         if (fops->eof(f))
 151                                 lbx_error_raise(LBX_EEOF);
 152                         free(img);
 153                         return NULL;
 154                 }
 155
 156                 img->palstart = unpack_16_le(buf+0);
 157                 img->palcount = unpack_16_le(buf+2);
 158                 img->paloff   = fops->tell(f);
 159
 160                 if (img->palstart + img->palcount > 256) {
 161                         lbx_error_raise(LBX_EFORMAT);
 162                         free(img);
 163                         return NULL;
 164                 }
 165         }
 166
 167         return &img->pub;
 168 }
 169
 170 static int pipe_close(void *f)
 171 {
 172         struct lbx_pipe_state *p = f;
 173         int rc;
 174
 175         rc = fclose(p->f);
 176         free(p);
 177         return rc;
 178 }
 179
 180 static int file_close(void *f)
 181 {
 182         return fclose((FILE *)f);
 183 }
 184
 185 struct lbx_image *lbx_img_fopen(const char *file)
 186 {
 187         struct lbx_pipe_state *p;
 188         FILE *f;
 189
 190         f = fopen(file, "rb");
 191         if (!f) {
 192                 lbx_error_raise(-errno);
 193                 return NULL;
 194         }
 195
 196         if (fseek(f, 0, SEEK_CUR) == 0)
 197                 return lbx_img_open(f, &lbx_default_fops, file_close);
 198
 199         p = malloc(sizeof *p);
 200         if (!p) {
 201                 lbx_error_raise(LBX_ENOMEM);
 202                 fclose(f);
 203                 return NULL;
 204         }
 205
 206         *p = (struct lbx_pipe_state) { .f = f };
 207         return lbx_img_open(p, &lbx_pipe_fops, pipe_close);
 208 }
 209
 210 int lbx_img_seek(struct lbx_image *pub, unsigned frame)
 211 {
 212         struct lbx_image_priv *img = (struct lbx_image_priv *)pub;
 213
 214         if (frame >= pub->frames) {
 215                 lbx_error_raise(LBX_EINVAL);
 216                 return -1;
 217         }
 218
 219         if (img->fops->seek(img->f, img->offsets[frame], SEEK_SET)) {
 220                 return -1;
 221         }
 222
 223         if (!(img->flags & FLAG_RAW)) {
 224                 unsigned char buf[4];
 225
 226                 /* Read frame header */
 227                 if (img->fops->read(buf, 4, img->f) != 4) {
 228                         if (img->fops->eof(img->f))
 229                                 lbx_error_raise(LBX_EEOF);
 230                         return -1;
 231                 }
 232
 233                 if (unpack_16_le(buf) != 1) {
 234                         lbx_error_raise(LBX_EFORMAT);
 235                         return -1;
 236                 }
 237
 238                 img->currentx = 0;
 239                 img->currenty = unpack_16_le(buf+2);
 240                 if (img->currenty > img->pub.height) {
 241                         lbx_error_raise(LBX_EFORMAT);
 242                         return -1;
 243                 }
 244         }
 245
 246         img->read_state = READ_STATE_HEADER;
 247         return 0;
 248 }
 249
 250 long lbx_img_read_row_header(struct lbx_image *pub, unsigned *x, unsigned *y)
 251 {
 252         struct lbx_image_priv *img = (struct lbx_image_priv *)pub;
 253         unsigned short length, offset;
 254         unsigned char buf[4];
 255
 256         if (img->read_state != READ_STATE_HEADER) {
 257                 lbx_error_raise(LBX_EINVAL);
 258                 return -1;
 259         }
 260
 261         /* Raw images have no row headers */
 262         if (img->flags & FLAG_RAW) {
 263                 img->currentn = img->pub.width;
 264                 *y = img->currenty++;
 265                 *x = 0;
 266
 267                 if (*y < img->pub.height) {
 268                         img->read_state = READ_STATE_DATA;
 269                         return img->currentn;
 270                 } else {
 271                         img->read_state = READ_STATE_DONE;
 272                         return 0;
 273                 }
 274         }
 275
 276         do {
 277                 if (img->fops->read(buf, sizeof buf, img->f) != sizeof buf) {
 278                         if (img->fops->eof(img->f))
 279                                 lbx_error_raise(LBX_EEOF);
 280                         return -1;
 281                 }
 282
 283                 length = unpack_16_le(buf+0);
 284                 offset = unpack_16_le(buf+2);
 285
 286                 if (length == 0) {
 287                         if (offset == 1000) {
 288                                 img->read_state = READ_STATE_DONE;
 289                                 return 0;
 290                         } else if (offset > img->pub.height - img->currenty) {
 291                                 lbx_error_raise(LBX_EFORMAT);
 292                                 return -1;
 293                         }
 294
 295                         img->currenty += offset;
 296                         img->currentx  = 0;
 297                 }
 298         } while (length == 0);
 299
 300         if (offset > img->pub.width - img->currentx) {
 301                 lbx_error_raise(LBX_EFORMAT);
 302                 return -1;
 303         }
 304         img->currentx += offset;
 305
 306         if (length > img->pub.width - img->currentx) {
 307                 lbx_error_raise(LBX_EFORMAT);
 308                 return -1;
 309         }
 310         img->currentn = length;
 311
 312         img->read_state = READ_STATE_DATA;
 313         *x = img->currentx;
 314         *y = img->currenty;
 315
 316         return img->currentn;
 317 }
 318
 319 long lbx_img_read_row_data(struct lbx_image *pub, void *buf)
 320 {
 321         struct lbx_image_priv *img = (struct lbx_image_priv *)pub;
 322
 323         if (img->read_state != READ_STATE_DATA) {
 324                 lbx_error_raise(LBX_EINVAL);
 325                 return -1;
 326         }
 327
 328         if (img->fops->read(buf, img->currentn, img->f) != img->currentn) {
 329                 if (img->fops->eof(img->f))
 330                         lbx_error_raise(LBX_EEOF);
 331                 return -1;
 332         }
 333
 334         if (!(img->flags & FLAG_RAW)) {
 335                 /* Skip padding byte, if any */
 336                 if (img->currentn % 2) {
 337                         if (img->fops->seek(img->f, 1, SEEK_CUR))
 338                                 return -1;
 339                 }
 340         }
 341
 342         img->read_state = READ_STATE_HEADER;
 343         img->currentx += img->currentn;
 344
 345         return img->currentn;
 346 }
 347
 348 int
 349 lbx_img_loadpalette(void *f, const struct lbx_file_ops *fops,
 350                     struct lbx_colour palette[static 256])
 351 {
 352         unsigned char entry[4];
 353         int i;
 354
 355         for (i = 0; i < 256; i++) {
 356                 if (fops->read(entry, sizeof entry, f) != sizeof entry) {
 357                         if (fops->eof(f))
 358                                 lbx_error_raise(LBX_EEOF);
 359                         return -1;
 360                 }
 361
 362                 if (entry[0] != 1) {
 363                         lbx_error_raise(LBX_EFORMAT);
 364                         return -1;
 365                 }
 366
 367                 palette[i] = (struct lbx_colour) {
 368                         .red    = entry[1] & 0x3f,
 369                         .green  = entry[2] & 0x3f,
 370                         .blue   = entry[3] & 0x3f,
 371                         .active = 1,
 372                 };
 373         }
 374
 375         return 0;
 376 }
 377
 378 int
 379 lbx_img_getpalette(struct lbx_image *pub, struct lbx_colour palette[static 256])
 380 {
 381         struct lbx_image_priv *img = (struct lbx_image_priv *)pub;
 382         unsigned char entry[4];
 383         unsigned int i;
 384         size_t rc;
 385
 386         /* Do nothing if the image doesn't have embedded palette data. */
 387         if (!(img->flags & FLAG_PALETTE))
 388                 return 0;
 389
 390         if (img->fops->seek(img->f, img->paloff, SEEK_SET)) {
 391                 return -1;
 392         }
 393
 394         for (i = 0; i < img->palcount; i++) {
 395                 rc = img->fops->read(entry, sizeof entry, img->f);
 396                 if (rc < sizeof entry) {
 397                         goto readerr;
 398                 }
 399
 400                 if (entry[0] != 0) {
 401                         lbx_error_raise(LBX_EFORMAT);
 402                         return -1;
 403                 }
 404
 405                 palette[img->palstart + i] = (struct lbx_colour){
 406                         .red    = entry[1],
 407                         .green  = entry[2],
 408                         .blue   = entry[3],
 409                         .active = 1,
 410                 };
 411         }
 412
 413         return 0;
 414 readerr:
 415         if (img->fops->eof(img->f))
 416                 lbx_error_raise(LBX_EEOF);
 417         return -1;
 418 }
 419
 420 void lbx_img_getinfo(struct lbx_image *pub, struct lbx_imginfo *info)
 421 {
 422         struct lbx_image_priv *img = (struct lbx_image_priv *)pub;
 423
 424         *info = (struct lbx_imginfo) {
 425                 .palettesz  = (img->flags & FLAG_PALETTE) ? img->palcount : 0,
 426         };
 427
 428         /* There seems to be two ways of specifying that an image loops. */
 429         if (img->flags & FLAG_LOOPING) {
 430                 info->loopstart = 0;
 431                 info->looping   = 1;
 432         } else if (img->pub.leadin != pub->frames - 1) {
 433                 info->loopstart = img->pub.leadin;
 434                 info->looping   = 1;
 435         }
 436 }
 437
 438 int lbx_img_close(struct lbx_image *pub)
 439 {
 440         struct lbx_image_priv *img = (struct lbx_image_priv *)pub;
 441         int rc = 0;
 442
 443         if (img && img->dtor) {
 444                 rc = img->dtor(img->f);
 445         }
 446         free(img);
 447
 448         return rc;
 449 }