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 <stdbool.h>
  24 #include <inttypes.h>
  25 #include <errno.h>
  26
  27 #include "pack.h"
  28 #include "misc.h"
  29 #include "lbx.h"
  30 #include "error.h"
  31 #include "image.h"
  32
  33 #define FLAG_RAW       0x0100 /* Image is stored as a flat array of bytes. */
  34 #define FLAG_OVERWRITE 0x0400 /* Draw each frame on a clean slate (unsure). */
  35 #define FLAG_BUILDING  0x0800 /* Buildings have this, related to shadow? */
  36 #define FLAG_PALETTE   0x1000 /* Image contains embedded palette. */
  37 #define FLAG_LOOPING   0x2000 /* Loop over all frames in the image (unsure). */
  38
  39 #define FLAG_ALL (FLAG_RAW|FLAG_OVERWRITE|FLAG_BUILDING|FLAG_PALETTE|FLAG_LOOPING)
  40
  41 #define HDR_LEN 12
  42
  43 /* States for image readout */
  44 enum {
  45         READ_STATE_INIT,
  46         READ_STATE_HEADER,
  47         READ_STATE_DATA,
  48         READ_STATE_DONE,
  49 };
  50
  51 struct lbx_image_priv {
  52         struct lbx_image pub;
  53
  54         unsigned short wtf, flags;
  55         unsigned char  wtf2;
  56
  57         const struct lbx_file_ops *fops;
  58         int (*dtor)(void *handle);
  59         void *f;
  60
  61         /* State of frame readout */
  62         unsigned currentx, currenty, currentn;
  63         int read_state;
  64
  65         unsigned long offsets[];
  66 };
  67
  68 static struct lbx_image_priv *lbx_img_init(unsigned char hdr[static HDR_LEN])
  69 {
  70         unsigned short nframes = unpack_16_le(hdr+6);
  71         struct lbx_image_priv *img;
  72
  73         img = malloc(sizeof *img + sizeof img->offsets[0] * (nframes+1));
  74         if (!img) {
  75                 lbx_error_raise(LBX_ENOMEM);
  76                 return NULL;
  77         }
  78
  79         *img = (struct lbx_image_priv) {
  80                 .pub.width  = unpack_16_le(hdr+0),
  81                 .pub.height = unpack_16_le(hdr+2),
  82                 .wtf        = unpack_16_le(hdr+4),
  83                 .pub.frames = hdr[6],
  84                 .wtf2       = hdr[7],
  85                 .pub.leadin = hdr[8],
  86                 .pub.chunk  = hdr[9],
  87                 .flags      = unpack_16_le(hdr+10),
  88         };
  89
  90         if (img->flags & FLAG_OVERWRITE)
  91                 img->pub.chunk = 1;
  92
  93         if (img->flags & FLAG_LOOPING)
  94                 img->pub.leadin = 0;
  95
  96         if (img->pub.leadin >= img->pub.frames) {
  97                 lbx_error_raise(LBX_EFORMAT);
  98                 free(img);
  99                 return NULL;
 100         }
 101
 102         return img;
 103 }
 104
 105 struct lbx_image *lbx_img_open(void *f, const struct lbx_file_ops *fops,
 106                                int (*destructor)(void *))
 107 {
 108         unsigned char hdr_buf[HDR_LEN];
 109         struct lbx_image_priv *img;
 110
 111         if (fops->read(hdr_buf, sizeof hdr_buf, f) != sizeof hdr_buf) {
 112                 if (fops->eof(f))
 113                         lbx_error_raise(LBX_EEOF);
 114                 return NULL;
 115         }
 116
 117         img = lbx_img_init(hdr_buf);
 118         if (!img)
 119                 return NULL;
 120
 121         img->f    = f;
 122         img->fops = fops;
 123         img->dtor = destructor;
 124
 125         /*
 126          * DEBUG ONLY.  These assertions exist to catch otherwise valid image
 127          * files which differ from what I believe to be true of all LBX images.
 128          * When we can decode every image, then these assertions should be
 129          * replaced with constraints.
 130          */
 131         _lbx_assert(img->wtf  == 0); /* version? */
 132         _lbx_assert(img->wtf2 == 0); /* very likely is simply reserved. */
 133         _lbx_assert(!(img->flags & ~FLAG_ALL));
 134
 135         /* Read all offsets.  Should be merged with identical code in lbx.c */
 136         for (unsigned i = 0; i <= img->pub.frames; i++) {
 137                 unsigned char buf[4];
 138
 139                 if (fops->read(buf, sizeof buf, f) != sizeof buf) {
 140                         if (fops->eof(f))
 141                                 lbx_error_raise(LBX_EEOF);
 142                         free(img);
 143                         return NULL;
 144                 }
 145
 146                 img->offsets[i] = unpack_32_le(buf);
 147         }
 148
 149         return &img->pub;
 150 }
 151
 152 static int pipe_close(void *f)
 153 {
 154         struct lbx_pipe_state *p = f;
 155         int rc;
 156
 157         rc = fclose(p->f);
 158         free(p);
 159         return rc;
 160 }
 161
 162 static int file_close(void *f)
 163 {
 164         return fclose((FILE *)f);
 165 }
 166
 167 struct lbx_image *lbx_img_fopen(const char *file)
 168 {
 169         struct lbx_pipe_state *p;
 170         FILE *f;
 171
 172         f = fopen(file, "rb");
 173         if (!f) {
 174                 lbx_error_raise(-errno);
 175                 return NULL;
 176         }
 177
 178         if (fseek(f, 0, SEEK_CUR) == 0)
 179                 return lbx_img_open(f, &lbx_default_fops, file_close);
 180
 181         p = malloc(sizeof *p);
 182         if (!p) {
 183                 lbx_error_raise(LBX_ENOMEM);
 184                 fclose(f);
 185                 return NULL;
 186         }
 187
 188         *p = (struct lbx_pipe_state) { .f = f };
 189         return lbx_img_open(p, &lbx_pipe_fops, pipe_close);
 190 }
 191
 192 int lbx_img_seek(struct lbx_image *pub, unsigned frame)
 193 {
 194         struct lbx_image_priv *img = (struct lbx_image_priv *)pub;
 195
 196         if (frame >= pub->frames) {
 197                 lbx_error_raise(LBX_EINVAL);
 198                 return -1;
 199         }
 200
 201         if (img->fops->seek(img->f, img->offsets[frame], SEEK_SET)) {
 202                 return -1;
 203         }
 204
 205         if (!(img->flags & FLAG_RAW)) {
 206                 unsigned char buf[4];
 207
 208                 /* Read frame header */
 209                 if (img->fops->read(buf, 4, img->f) != 4) {
 210                         if (img->fops->eof(img->f))
 211                                 lbx_error_raise(LBX_EEOF);
 212                         return -1;
 213                 }
 214
 215                 if (unpack_16_le(buf) != 1) {
 216                         lbx_error_raise(LBX_EFORMAT);
 217                         return -1;
 218                 }
 219
 220                 img->currentx = 0;
 221                 img->currenty = unpack_16_le(buf+2);
 222                 if (img->currenty > img->pub.height) {
 223                         lbx_error_raise(LBX_EFORMAT);
 224                         return -1;
 225                 }
 226         }
 227
 228         img->read_state = READ_STATE_HEADER;
 229         return 0;
 230 }
 231
 232 long lbx_img_read_row_header(struct lbx_image *pub, unsigned *x, unsigned *y)
 233 {
 234         struct lbx_image_priv *img = (struct lbx_image_priv *)pub;
 235         unsigned short length, offset;
 236         unsigned char buf[4];
 237
 238         if (img->read_state != READ_STATE_HEADER) {
 239                 lbx_error_raise(LBX_EINVAL);
 240                 return -1;
 241         }
 242
 243         /* Raw images have no row headers */
 244         if (img->flags & FLAG_RAW) {
 245                 img->currentn = img->pub.width;
 246                 *y = img->currenty++;
 247                 *x = 0;
 248
 249                 if (*y < img->pub.height) {
 250                         img->read_state = READ_STATE_DATA;
 251                         return img->currentn;
 252                 } else {
 253                         img->read_state = READ_STATE_DONE;
 254                         return 0;
 255                 }
 256         }
 257
 258         do {
 259                 if (img->fops->read(buf, sizeof buf, img->f) != sizeof buf) {
 260                         if (img->fops->eof(img->f))
 261                                 lbx_error_raise(LBX_EEOF);
 262                         return -1;
 263                 }
 264
 265                 length = unpack_16_le(buf+0);
 266                 offset = unpack_16_le(buf+2);
 267
 268                 if (length == 0) {
 269                         if (offset == 1000) {
 270                                 img->read_state = READ_STATE_DONE;
 271                                 return 0;
 272                         } else if (offset > img->pub.height - img->currenty) {
 273                                 lbx_error_raise(LBX_EFORMAT);
 274                                 return -1;
 275                         }
 276
 277                         img->currenty += offset;
 278                         img->currentx  = 0;
 279                 }
 280         } while (length == 0);
 281
 282         if (offset > img->pub.width - img->currentx) {
 283                 lbx_error_raise(LBX_EFORMAT);
 284                 return -1;
 285         }
 286         img->currentx += offset;
 287
 288         if (length > img->pub.width - img->currentx) {
 289                 lbx_error_raise(LBX_EFORMAT);
 290                 return -1;
 291         }
 292         img->currentn = length;
 293
 294         img->read_state = READ_STATE_DATA;
 295         *x = img->currentx;
 296         *y = img->currenty;
 297
 298         return img->currentn;
 299 }
 300
 301 long lbx_img_read_row_data(struct lbx_image *pub, void *buf)
 302 {
 303         struct lbx_image_priv *img = (struct lbx_image_priv *)pub;
 304
 305         if (img->read_state != READ_STATE_DATA) {
 306                 lbx_error_raise(LBX_EINVAL);
 307                 return -1;
 308         }
 309
 310         if (img->fops->read(buf, img->currentn, img->f) != img->currentn) {
 311                 if (img->fops->eof(img->f))
 312                         lbx_error_raise(LBX_EEOF);
 313                 return -1;
 314         }
 315
 316         if (!(img->flags & FLAG_RAW)) {
 317                 /* Skip padding byte, if any */
 318                 if (img->currentn % 2) {
 319                         if (img->fops->seek(img->f, 1, SEEK_CUR))
 320                                 return -1;
 321                 }
 322         }
 323
 324         img->read_state = READ_STATE_HEADER;
 325         img->currentx += img->currentn;
 326
 327         return img->currentn;
 328 }
 329
 330 static int read_palette(void *f, const struct lbx_file_ops *fops,
 331                         struct lbx_colour *palette, unsigned count,
 332                         bool external)
 333 {
 334         assert(count <= 256);
 335         for (unsigned i = 0; i < count; i++) {
 336                 unsigned char buf[4];
 337
 338                 if (fops->read(buf, 4, f) != 4) {
 339                         if (fops->eof(f))
 340                                 lbx_error_raise(LBX_EEOF);
 341                         return -1;
 342                 }
 343
 344                 if (buf[0] != external) {
 345                         lbx_error_raise(LBX_EFORMAT);
 346                         return -1;
 347                 }
 348
 349                 palette[i] = (struct lbx_colour) {
 350                         .red    = buf[1] & 0x3f,
 351                         .green  = buf[2] & 0x3f,
 352                         .blue   = buf[3] & 0x3f,
 353                         .active = 1,
 354                 };
 355         }
 356
 357         return 0;
 358 }
 359
 360 int lbx_img_loadpalette(void *f, const struct lbx_file_ops *fops,
 361                         struct lbx_colour *palette)
 362 {
 363         return read_palette(f, fops, palette, 256, true);
 364 }
 365
 366 int lbx_img_getpalette(struct lbx_image *pub, struct lbx_colour *out)
 367 {
 368         struct lbx_image_priv *img = (struct lbx_image_priv *)pub;
 369         unsigned long palette_start, palette_count, palette_offset;
 370         unsigned char buf[4];
 371         int rc;
 372
 373         /* Do nothing if the image doesn't have embedded palette data. */
 374         if (!(img->flags & FLAG_PALETTE))
 375                 return 0;
 376
 377         palette_offset = 16 + 4ul * img->pub.frames;
 378         if (img->fops->seek(img->f, palette_offset, SEEK_SET)) {
 379                 return -1;
 380         }
 381
 382         /* Read embedded palette header */
 383         if (img->fops->read(buf, 4, img->f) < 4)
 384                 goto readerr;
 385
 386         palette_start = unpack_16_le(buf+0);
 387         palette_count = unpack_16_le(buf+2);
 388         if (palette_start + palette_count > 256) {
 389                 lbx_error_raise(LBX_EFORMAT);
 390                 return -1;
 391         }
 392
 393         if (out) {
 394                 rc = read_palette(img->f, img->fops,
 395                                   out+palette_start, palette_count,
 396                                   false);
 397                 if (rc < 0)
 398                         return -1;
 399         }
 400
 401         return palette_count;
 402 readerr:
 403         if (img->fops->eof(img->f))
 404                 lbx_error_raise(LBX_EEOF);
 405         return -1;
 406 }
 407
 408 int lbx_img_close(struct lbx_image *pub)
 409 {
 410         struct lbx_image_priv *img = (struct lbx_image_priv *)pub;
 411         int rc = 0;
 412
 413         if (img && img->dtor) {
 414                 rc = img->dtor(img->f);
 415         }
 416         free(img);
 417
 418         return rc;
 419 }