jpeg.c

   1 /*
   2         Copyright (C) 2002  Mathieu Olivier
   3
   4         This program is free software; you can redistribute it and/or
   5         modify it under the terms of the GNU General Public License
   6         as published by the Free Software Foundation; either version 2
   7         of the License, or (at your option) any later version.
   8
   9         This program is distributed in the hope that it will be useful,
  10         but WITHOUT ANY WARRANTY; without even the implied warranty of
  11         MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
  12
  13         See the GNU General Public License for more details.
  14
  15         You should have received a copy of the GNU General Public License
  16         along with this program; if not, write to:
  17
  18                 Free Software Foundation, Inc.
  19                 59 Temple Place - Suite 330
  20                 Boston, MA  02111-1307, USA
  21
  22 */
  23
  24
  25 #include "quakedef.h"
  26 #include "image.h"
  27 #include "jpeg.h"
  28
  29
  30 /*
  31 =================================================================
  32
  33   Minimal set of definitions from the JPEG lib
  34
  35   WARNING: for a matter of simplicity, several pointer types are
  36   casted to "void*", and most enumerated values are not included
  37
  38 =================================================================
  39 */
  40
  41 // jboolean is unsigned char instead of int on Win32
  42 #ifdef WIN32
  43 typedef unsigned char jboolean;
  44 #else
  45 typedef int jboolean;
  46 #endif
  47
  48 #define JPEG_LIB_VERSION  62  // Version 6b
  49
  50 typedef void *j_common_ptr;
  51 typedef struct jpeg_compress_struct *j_compress_ptr;
  52 typedef struct jpeg_decompress_struct *j_decompress_ptr;
  53 typedef enum
  54 {
  55         JCS_UNKNOWN,
  56         JCS_GRAYSCALE,
  57         JCS_RGB,
  58         JCS_YCbCr,
  59         JCS_CMYK,
  60         JCS_YCCK
  61 } J_COLOR_SPACE;
  62 typedef enum {JPEG_DUMMY1} J_DCT_METHOD;
  63 typedef enum {JPEG_DUMMY2} J_DITHER_MODE;
  64 typedef unsigned int JDIMENSION;
  65
  66 #define JPOOL_PERMANENT 0       // lasts until master record is destroyed
  67 #define JPOOL_IMAGE             1       // lasts until done with image/datastream
  68
  69 #define JPEG_EOI        0xD9  // EOI marker code
  70
  71 #define JMSG_STR_PARM_MAX  80
  72
  73 #define DCTSIZE2 64
  74 #define NUM_QUANT_TBLS 4
  75 #define NUM_HUFF_TBLS 4
  76 #define NUM_ARITH_TBLS 16
  77 #define MAX_COMPS_IN_SCAN 4
  78 #define C_MAX_BLOCKS_IN_MCU 10
  79 #define D_MAX_BLOCKS_IN_MCU 10
  80
  81 struct jpeg_memory_mgr
  82 {
  83   void* (*alloc_small) (j_common_ptr cinfo, int pool_id, size_t sizeofobject);
  84   void (*alloc_large) ();
  85   void (*alloc_sarray) ();
  86   void (*alloc_barray) ();
  87   void (*request_virt_sarray) ();
  88   void (*request_virt_barray) ();
  89   void (*realize_virt_arrays) ();
  90   void (*access_virt_sarray) ();
  91   void (*access_virt_barray) ();
  92   void (*free_pool) ();
  93   void (*self_destruct) ();
  94
  95   long max_memory_to_use;
  96   long max_alloc_chunk;
  97 };
  98
  99 struct jpeg_error_mgr
 100 {
 101         void (*error_exit) (j_common_ptr cinfo);
 102         void (*emit_message) (j_common_ptr cinfo, int msg_level);
 103         void (*output_message) (j_common_ptr cinfo);
 104         void (*format_message) (j_common_ptr cinfo, char * buffer);
 105         void (*reset_error_mgr) (j_common_ptr cinfo);
 106         int msg_code;
 107         union {
 108                 int i[8];
 109                 char s[JMSG_STR_PARM_MAX];
 110         } msg_parm;
 111         int trace_level;
 112         long num_warnings;
 113         const char * const * jpeg_message_table;
 114         int last_jpeg_message;
 115         const char * const * addon_message_table;
 116         int first_addon_message;
 117         int last_addon_message;
 118 };
 119
 120 struct jpeg_source_mgr
 121 {
 122         const unsigned char *next_input_byte;
 123         size_t bytes_in_buffer;
 124
 125         void (*init_source) (j_decompress_ptr cinfo);
 126         jboolean (*fill_input_buffer) (j_decompress_ptr cinfo);
 127         void (*skip_input_data) (j_decompress_ptr cinfo, long num_bytes);
 128         jboolean (*resync_to_restart) (j_decompress_ptr cinfo, int desired);
 129         void (*term_source) (j_decompress_ptr cinfo);
 130 };
 131
 132 typedef struct {
 133   /* These values are fixed over the whole image. */
 134   /* For compression, they must be supplied by parameter setup; */
 135   /* for decompression, they are read from the SOF marker. */
 136   int component_id;             /* identifier for this component (0..255) */
 137   int component_index;          /* its index in SOF or cinfo->comp_info[] */
 138   int h_samp_factor;            /* horizontal sampling factor (1..4) */
 139   int v_samp_factor;            /* vertical sampling factor (1..4) */
 140   int quant_tbl_no;             /* quantization table selector (0..3) */
 141   /* These values may vary between scans. */
 142   /* For compression, they must be supplied by parameter setup; */
 143   /* for decompression, they are read from the SOS marker. */
 144   /* The decompressor output side may not use these variables. */
 145   int dc_tbl_no;                /* DC entropy table selector (0..3) */
 146   int ac_tbl_no;                /* AC entropy table selector (0..3) */
 147
 148   /* Remaining fields should be treated as private by applications. */
 149
 150   /* These values are computed during compression or decompression startup: */
 151   /* Component's size in DCT blocks.
 152    * Any dummy blocks added to complete an MCU are not counted; therefore
 153    * these values do not depend on whether a scan is interleaved or not.
 154    */
 155   JDIMENSION width_in_blocks;
 156   JDIMENSION height_in_blocks;
 157   /* Size of a DCT block in samples.  Always DCTSIZE for compression.
 158    * For decompression this is the size of the output from one DCT block,
 159    * reflecting any scaling we choose to apply during the IDCT step.
 160    * Values of 1,2,4,8 are likely to be supported.  Note that different
 161    * components may receive different IDCT scalings.
 162    */
 163   int DCT_scaled_size;
 164   /* The downsampled dimensions are the component's actual, unpadded number
 165    * of samples at the main buffer (preprocessing/compression interface), thus
 166    * downsampled_width = ceil(image_width * Hi/Hmax)
 167    * and similarly for height.  For decompression, IDCT scaling is included, so
 168    * downsampled_width = ceil(image_width * Hi/Hmax * DCT_scaled_size/DCTSIZE)
 169    */
 170   JDIMENSION downsampled_width;  /* actual width in samples */
 171   JDIMENSION downsampled_height; /* actual height in samples */
 172   /* This flag is used only for decompression.  In cases where some of the
 173    * components will be ignored (eg grayscale output from YCbCr image),
 174    * we can skip most computations for the unused components.
 175    */
 176   jboolean component_needed;     /* do we need the value of this component? */
 177
 178   /* These values are computed before starting a scan of the component. */
 179   /* The decompressor output side may not use these variables. */
 180   int MCU_width;                /* number of blocks per MCU, horizontally */
 181   int MCU_height;               /* number of blocks per MCU, vertically */
 182   int MCU_blocks;               /* MCU_width * MCU_height */
 183   int MCU_sample_width;         /* MCU width in samples, MCU_width*DCT_scaled_size */
 184   int last_col_width;           /* # of non-dummy blocks across in last MCU */
 185   int last_row_height;          /* # of non-dummy blocks down in last MCU */
 186
 187   /* Saved quantization table for component; NULL if none yet saved.
 188    * See jdinput.c comments about the need for this information.
 189    * This field is currently used only for decompression.
 190    */
 191   void *quant_table;
 192
 193   /* Private per-component storage for DCT or IDCT subsystem. */
 194   void * dct_table;
 195 } jpeg_component_info;
 196
 197 struct jpeg_decompress_struct
 198 {
 199         struct jpeg_error_mgr *err;             // USED
 200         struct jpeg_memory_mgr *mem;    // USED
 201
 202         void *progress;
 203         void *client_data;
 204         jboolean is_decompressor;
 205         int global_state;
 206
 207         struct jpeg_source_mgr *src;    // USED
 208         JDIMENSION image_width;                 // USED
 209         JDIMENSION image_height;                // USED
 210
 211         int num_components;
 212         J_COLOR_SPACE jpeg_color_space;
 213         J_COLOR_SPACE out_color_space;
 214         unsigned int scale_num, scale_denom;
 215         double output_gamma;
 216         jboolean buffered_image;
 217         jboolean raw_data_out;
 218         J_DCT_METHOD dct_method;
 219         jboolean do_fancy_upsampling;
 220         jboolean do_block_smoothing;
 221         jboolean quantize_colors;
 222         J_DITHER_MODE dither_mode;
 223         jboolean two_pass_quantize;
 224         int desired_number_of_colors;
 225         jboolean enable_1pass_quant;
 226         jboolean enable_external_quant;
 227         jboolean enable_2pass_quant;
 228         JDIMENSION output_width;
 229
 230         JDIMENSION output_height;       // USED
 231
 232         int out_color_components;
 233
 234         int output_components;          // USED
 235
 236         int rec_outbuf_height;
 237         int actual_number_of_colors;
 238         void *colormap;
 239
 240         JDIMENSION output_scanline;     // USED
 241
 242         int input_scan_number;
 243         JDIMENSION input_iMCU_row;
 244         int output_scan_number;
 245         JDIMENSION output_iMCU_row;
 246         int (*coef_bits)[DCTSIZE2];
 247         void *quant_tbl_ptrs[NUM_QUANT_TBLS];
 248         void *dc_huff_tbl_ptrs[NUM_HUFF_TBLS];
 249         void *ac_huff_tbl_ptrs[NUM_HUFF_TBLS];
 250         int data_precision;
 251         jpeg_component_info *comp_info;
 252         jboolean progressive_mode;
 253         jboolean arith_code;
 254         unsigned char arith_dc_L[NUM_ARITH_TBLS];
 255         unsigned char arith_dc_U[NUM_ARITH_TBLS];
 256         unsigned char arith_ac_K[NUM_ARITH_TBLS];
 257         unsigned int restart_interval;
 258         jboolean saw_JFIF_marker;
 259         unsigned char JFIF_major_version;
 260         unsigned char JFIF_minor_version;
 261         unsigned char density_unit;
 262         unsigned short X_density;
 263         unsigned short Y_density;
 264         jboolean saw_Adobe_marker;
 265         unsigned char Adobe_transform;
 266         jboolean CCIR601_sampling;
 267         void *marker_list;
 268         int max_h_samp_factor;
 269         int max_v_samp_factor;
 270         int min_DCT_scaled_size;
 271         JDIMENSION total_iMCU_rows;
 272         void *sample_range_limit;
 273         int comps_in_scan;
 274         jpeg_component_info *cur_comp_info[MAX_COMPS_IN_SCAN];
 275         JDIMENSION MCUs_per_row;
 276         JDIMENSION MCU_rows_in_scan;
 277         int blocks_in_MCU;
 278         int MCU_membership[D_MAX_BLOCKS_IN_MCU];
 279         int Ss, Se, Ah, Al;
 280         int unread_marker;
 281         void *master;
 282         void *main;
 283         void *coef;
 284         void *post;
 285         void *inputctl;
 286         void *marker;
 287         void *entropy;
 288         void *idct;
 289         void *upsample;
 290         void *cconvert;
 291         void *cquantize;
 292 };
 293
 294
 295 struct jpeg_compress_struct
 296 {
 297         struct jpeg_error_mgr *err;
 298         struct jpeg_memory_mgr *mem;
 299         void *progress;
 300         void *client_data;
 301         jboolean is_decompressor;
 302         int global_state;
 303
 304         void *dest;
 305         JDIMENSION image_width;
 306         JDIMENSION image_height;
 307         int input_components;
 308         J_COLOR_SPACE in_color_space;
 309         double input_gamma;
 310         int data_precision;
 311
 312         int num_components;
 313         J_COLOR_SPACE jpeg_color_space;
 314         jpeg_component_info *comp_info;
 315         void *quant_tbl_ptrs[NUM_QUANT_TBLS];
 316         void *dc_huff_tbl_ptrs[NUM_HUFF_TBLS];
 317         void *ac_huff_tbl_ptrs[NUM_HUFF_TBLS];
 318         unsigned char arith_dc_L[NUM_ARITH_TBLS];
 319         unsigned char arith_dc_U[NUM_ARITH_TBLS];
 320         unsigned char arith_ac_K[NUM_ARITH_TBLS];
 321
 322         int num_scans;
 323         const void *scan_info;
 324         jboolean raw_data_in;
 325         jboolean arith_code;
 326         jboolean optimize_coding;
 327         jboolean CCIR601_sampling;
 328         int smoothing_factor;
 329         J_DCT_METHOD dct_method;
 330
 331         unsigned int restart_interval;
 332         int restart_in_rows;
 333
 334         jboolean write_JFIF_header;
 335         unsigned char JFIF_major_version;
 336         unsigned char JFIF_minor_version;
 337         unsigned char density_unit;
 338         unsigned short X_density;
 339         unsigned short Y_density;
 340         jboolean write_Adobe_marker;
 341         JDIMENSION next_scanline;
 342
 343         jboolean progressive_mode;
 344         int max_h_samp_factor;
 345         int max_v_samp_factor;
 346         JDIMENSION total_iMCU_rows;
 347         int comps_in_scan;
 348         jpeg_component_info *cur_comp_info[MAX_COMPS_IN_SCAN];
 349         JDIMENSION MCUs_per_row;
 350         JDIMENSION MCU_rows_in_scan;
 351         int blocks_in_MCU;
 352         int MCU_membership[C_MAX_BLOCKS_IN_MCU];
 353         int Ss, Se, Ah, Al;
 354
 355         void *master;
 356         void *main;
 357         void *prep;
 358         void *coef;
 359         void *marker;
 360         void *cconvert;
 361         void *downsample;
 362         void *fdct;
 363         void *entropy;
 364         void *script_space;
 365         int script_space_size;
 366 };
 367
 368 struct jpeg_destination_mgr
 369 {
 370         unsigned char* next_output_byte;
 371         size_t free_in_buffer;
 372
 373         void (*init_destination) (j_compress_ptr cinfo);
 374         jboolean (*empty_output_buffer) (j_compress_ptr cinfo);
 375         void (*term_destination) (j_compress_ptr cinfo);
 376 };
 377
 378
 379 /*
 380 =================================================================
 381
 382   DarkPlaces definitions
 383
 384 =================================================================
 385 */
 386
 387 // Functions exported from libjpeg
 388 #define qjpeg_create_compress(cinfo) \
 389         qjpeg_CreateCompress((cinfo), JPEG_LIB_VERSION, (size_t) sizeof(struct jpeg_compress_struct))
 390 #define qjpeg_create_decompress(cinfo) \
 391         qjpeg_CreateDecompress((cinfo), JPEG_LIB_VERSION, (size_t) sizeof(struct jpeg_decompress_struct))
 392
 393 static void (*qjpeg_CreateCompress) (j_compress_ptr cinfo, int version, size_t structsize);
 394 static void (*qjpeg_CreateDecompress) (j_decompress_ptr cinfo, int version, size_t structsize);
 395 static void (*qjpeg_destroy_compress) (j_compress_ptr cinfo);
 396 static void (*qjpeg_destroy_decompress) (j_decompress_ptr cinfo);
 397 static void (*qjpeg_finish_compress) (j_compress_ptr cinfo);
 398 static jboolean (*qjpeg_finish_decompress) (j_decompress_ptr cinfo);
 399 static jboolean (*qjpeg_resync_to_restart) (j_decompress_ptr cinfo, int desired);
 400 static int (*qjpeg_read_header) (j_decompress_ptr cinfo, jboolean require_image);
 401 static JDIMENSION (*qjpeg_read_scanlines) (j_decompress_ptr cinfo, unsigned char** scanlines, JDIMENSION max_lines);
 402 static void (*qjpeg_set_defaults) (j_compress_ptr cinfo);
 403 static void (*qjpeg_set_quality) (j_compress_ptr cinfo, int quality, jboolean force_baseline);
 404 static jboolean (*qjpeg_start_compress) (j_compress_ptr cinfo, jboolean write_all_tables);
 405 static jboolean (*qjpeg_start_decompress) (j_decompress_ptr cinfo);
 406 static struct jpeg_error_mgr* (*qjpeg_std_error) (struct jpeg_error_mgr *err);
 407 static JDIMENSION (*qjpeg_write_scanlines) (j_compress_ptr cinfo, unsigned char** scanlines, JDIMENSION num_lines);
 408
 409 static dllfunction_t jpegfuncs[] =
 410 {
 411         {"jpeg_CreateCompress",         (void **) &qjpeg_CreateCompress},
 412         {"jpeg_CreateDecompress",       (void **) &qjpeg_CreateDecompress},
 413         {"jpeg_destroy_compress",       (void **) &qjpeg_destroy_compress},
 414         {"jpeg_destroy_decompress",     (void **) &qjpeg_destroy_decompress},
 415         {"jpeg_finish_compress",        (void **) &qjpeg_finish_compress},
 416         {"jpeg_finish_decompress",      (void **) &qjpeg_finish_decompress},
 417         {"jpeg_resync_to_restart",      (void **) &qjpeg_resync_to_restart},
 418         {"jpeg_read_header",            (void **) &qjpeg_read_header},
 419         {"jpeg_read_scanlines",         (void **) &qjpeg_read_scanlines},
 420         {"jpeg_set_defaults",           (void **) &qjpeg_set_defaults},
 421         {"jpeg_set_quality",            (void **) &qjpeg_set_quality},
 422         {"jpeg_start_compress",         (void **) &qjpeg_start_compress},
 423         {"jpeg_start_decompress",       (void **) &qjpeg_start_decompress},
 424         {"jpeg_std_error",                      (void **) &qjpeg_std_error},
 425         {"jpeg_write_scanlines",        (void **) &qjpeg_write_scanlines},
 426         {NULL, NULL}
 427 };
 428
 429 // Handle for JPEG DLL
 430 dllhandle_t jpeg_dll = NULL;
 431 qboolean jpeg_tried_loading = 0;
 432
 433 static unsigned char jpeg_eoi_marker [2] = {0xFF, JPEG_EOI};
 434 static qboolean error_in_jpeg;
 435
 436 // Our own output manager for JPEG compression
 437 typedef struct
 438 {
 439         struct jpeg_destination_mgr pub;
 440
 441         qfile_t* outfile;
 442         unsigned char* buffer;
 443         size_t bufsize; // used if outfile is NULL
 444 } my_destination_mgr;
 445 typedef my_destination_mgr* my_dest_ptr;
 446
 447
 448 /*
 449 =================================================================
 450
 451   DLL load & unload
 452
 453 =================================================================
 454 */
 455
 456 /*
 457 ====================
 458 JPEG_OpenLibrary
 459
 460 Try to load the JPEG DLL
 461 ====================
 462 */
 463 qboolean JPEG_OpenLibrary (void)
 464 {
 465         const char* dllnames [] =
 466         {
 467 #if defined(WIN64)
 468                 "libjpeg64.dll",
 469 #elif defined(WIN32)
 470                 "libjpeg.dll",
 471 #elif defined(MACOSX)
 472                 "libjpeg.62.dylib",
 473 #else
 474                 "libjpeg.so.62",
 475                 "libjpeg.so",
 476 #endif
 477                 NULL
 478         };
 479
 480         // Already loaded?
 481         if (jpeg_dll)
 482                 return true;
 483
 484         if (jpeg_tried_loading) // only try once
 485                 return false;
 486
 487         jpeg_tried_loading = true;
 488
 489         // Load the DLL
 490         return Sys_LoadLibrary (dllnames, &jpeg_dll, jpegfuncs);
 491 }
 492
 493
 494 /*
 495 ====================
 496 JPEG_CloseLibrary
 497
 498 Unload the JPEG DLL
 499 ====================
 500 */
 501 void JPEG_CloseLibrary (void)
 502 {
 503         Sys_UnloadLibrary (&jpeg_dll);
 504 }
 505
 506
 507 /*
 508 =================================================================
 509
 510         JPEG decompression
 511
 512 =================================================================
 513 */
 514
 515 static void JPEG_Noop (j_decompress_ptr cinfo) {}
 516
 517 static jboolean JPEG_FillInputBuffer (j_decompress_ptr cinfo)
 518 {
 519     // Insert a fake EOI marker
 520     cinfo->src->next_input_byte = jpeg_eoi_marker;
 521     cinfo->src->bytes_in_buffer = 2;
 522
 523         return TRUE;
 524 }
 525
 526 static void JPEG_SkipInputData (j_decompress_ptr cinfo, long num_bytes)
 527 {
 528     if (cinfo->src->bytes_in_buffer <= (unsigned long)num_bytes)
 529         {
 530                 cinfo->src->bytes_in_buffer = 0;
 531                 return;
 532         }
 533
 534     cinfo->src->next_input_byte += num_bytes;
 535     cinfo->src->bytes_in_buffer -= num_bytes;
 536 }
 537
 538 static void JPEG_MemSrc (j_decompress_ptr cinfo, const unsigned char *buffer, size_t filesize)
 539 {
 540         cinfo->src = (struct jpeg_source_mgr *)cinfo->mem->alloc_small ((j_common_ptr) cinfo, JPOOL_PERMANENT, sizeof (struct jpeg_source_mgr));
 541
 542         cinfo->src->next_input_byte = buffer;
 543         cinfo->src->bytes_in_buffer = filesize;
 544
 545         cinfo->src->init_source = JPEG_Noop;
 546         cinfo->src->fill_input_buffer = JPEG_FillInputBuffer;
 547         cinfo->src->skip_input_data = JPEG_SkipInputData;
 548         cinfo->src->resync_to_restart = qjpeg_resync_to_restart; // use the default method
 549         cinfo->src->term_source = JPEG_Noop;
 550 }
 551
 552 static void JPEG_ErrorExit (j_common_ptr cinfo)
 553 {
 554         ((struct jpeg_decompress_struct*)cinfo)->err->output_message (cinfo);
 555         error_in_jpeg = true;
 556 }
 557
 558
 559 /*
 560 ====================
 561 JPEG_LoadImage
 562
 563 Load a JPEG image into a BGRA buffer
 564 ====================
 565 */
 566 unsigned char* JPEG_LoadImage_BGRA (const unsigned char *f, int filesize)
 567 {
 568         struct jpeg_decompress_struct cinfo;
 569         struct jpeg_error_mgr jerr;
 570         unsigned char *image_buffer, *scanline;
 571         unsigned int line;
 572
 573         // No DLL = no JPEGs
 574         if (!jpeg_dll)
 575                 return NULL;
 576
 577         cinfo.err = qjpeg_std_error (&jerr);
 578         qjpeg_create_decompress (&cinfo);
 579         JPEG_MemSrc (&cinfo, f, filesize);
 580         qjpeg_read_header (&cinfo, TRUE);
 581         qjpeg_start_decompress (&cinfo);
 582
 583         image_width = cinfo.image_width;
 584         image_height = cinfo.image_height;
 585
 586         if (image_width > 4096 || image_height > 4096 || image_width <= 0 || image_height <= 0)
 587         {
 588                 Con_Printf("JPEG_LoadImage: invalid image size %ix%i\n", image_width, image_height);
 589                 return NULL;
 590         }
 591
 592         image_buffer = (unsigned char *)Mem_Alloc(tempmempool, image_width * image_height * 4);
 593         scanline = (unsigned char *)Mem_Alloc(tempmempool, image_width * cinfo.output_components);
 594         if (!image_buffer || !scanline)
 595         {
 596                 if (image_buffer)
 597                         Mem_Free (image_buffer);
 598                 if (scanline)
 599                         Mem_Free (scanline);
 600
 601                 Con_Printf("JPEG_LoadImage: not enough memory for %i by %i image\n", image_width, image_height);
 602                 qjpeg_finish_decompress (&cinfo);
 603                 qjpeg_destroy_decompress (&cinfo);
 604                 return NULL;
 605         }
 606
 607         // Decompress the image, line by line
 608         line = 0;
 609         while (cinfo.output_scanline < cinfo.output_height)
 610         {
 611                 unsigned char *buffer_ptr;
 612                 int ind;
 613
 614                 qjpeg_read_scanlines (&cinfo, &scanline, 1);
 615
 616                 // Convert the image to BGRA
 617                 switch (cinfo.output_components)
 618                 {
 619                         // RGB images
 620                         case 3:
 621                                 buffer_ptr = &image_buffer[image_width * line * 4];
 622                                 for (ind = 0; ind < image_width * 3; ind += 3, buffer_ptr += 4)
 623                                 {
 624                                         buffer_ptr[2] = scanline[ind];
 625                                         buffer_ptr[1] = scanline[ind + 1];
 626                                         buffer_ptr[0] = scanline[ind + 2];
 627                                         buffer_ptr[3] = 255;
 628                                 }
 629                                 break;
 630
 631                         // Greyscale images (default to it, just in case)
 632                         case 1:
 633                         default:
 634                                 buffer_ptr = &image_buffer[image_width * line * 4];
 635                                 for (ind = 0; ind < image_width; ind++, buffer_ptr += 4)
 636                                 {
 637                                         buffer_ptr[0] = scanline[ind];
 638                                         buffer_ptr[1] = scanline[ind];
 639                                         buffer_ptr[2] = scanline[ind];
 640                                         buffer_ptr[3] = 255;
 641                                 }
 642                 }
 643
 644                 line++;
 645         }
 646         Mem_Free (scanline);
 647
 648         qjpeg_finish_decompress (&cinfo);
 649         qjpeg_destroy_decompress (&cinfo);
 650
 651         return image_buffer;
 652 }
 653
 654
 655 /*
 656 =================================================================
 657
 658   JPEG compression
 659
 660 =================================================================
 661 */
 662
 663 #define JPEG_OUTPUT_BUF_SIZE 4096
 664 static void JPEG_InitDestination (j_compress_ptr cinfo)
 665 {
 666         my_dest_ptr dest = (my_dest_ptr)cinfo->dest;
 667         dest->buffer = (unsigned char*)cinfo->mem->alloc_small ((j_common_ptr) cinfo, JPOOL_IMAGE, JPEG_OUTPUT_BUF_SIZE * sizeof(unsigned char));
 668         dest->pub.next_output_byte = dest->buffer;
 669         dest->pub.free_in_buffer = JPEG_OUTPUT_BUF_SIZE;
 670 }
 671
 672 static jboolean JPEG_EmptyOutputBuffer (j_compress_ptr cinfo)
 673 {
 674         my_dest_ptr dest = (my_dest_ptr)cinfo->dest;
 675
 676         if (FS_Write (dest->outfile, dest->buffer, JPEG_OUTPUT_BUF_SIZE) != (size_t) JPEG_OUTPUT_BUF_SIZE)
 677         {
 678                 error_in_jpeg = true;
 679                 return false;
 680         }
 681
 682         dest->pub.next_output_byte = dest->buffer;
 683         dest->pub.free_in_buffer = JPEG_OUTPUT_BUF_SIZE;
 684         return true;
 685 }
 686
 687 static void JPEG_TermDestination (j_compress_ptr cinfo)
 688 {
 689         my_dest_ptr dest = (my_dest_ptr)cinfo->dest;
 690         size_t datacount = JPEG_OUTPUT_BUF_SIZE - dest->pub.free_in_buffer;
 691
 692         // Write any data remaining in the buffer
 693         if (datacount > 0)
 694                 if (FS_Write (dest->outfile, dest->buffer, datacount) != (fs_offset_t)datacount)
 695                         error_in_jpeg = true;
 696 }
 697
 698 static void JPEG_FileDest (j_compress_ptr cinfo, qfile_t* outfile)
 699 {
 700         my_dest_ptr dest;
 701
 702         // First time for this JPEG object?
 703         if (cinfo->dest == NULL)
 704                 cinfo->dest = (struct jpeg_destination_mgr *)(*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_PERMANENT, sizeof(my_destination_mgr));
 705
 706         dest = (my_dest_ptr)cinfo->dest;
 707         dest->pub.init_destination = JPEG_InitDestination;
 708         dest->pub.empty_output_buffer = JPEG_EmptyOutputBuffer;
 709         dest->pub.term_destination = JPEG_TermDestination;
 710         dest->outfile = outfile;
 711 }
 712
 713 static void JPEG_Mem_InitDestination (j_compress_ptr cinfo)
 714 {
 715         my_dest_ptr dest = (my_dest_ptr)cinfo->dest;
 716         dest->pub.next_output_byte = dest->buffer;
 717         dest->pub.free_in_buffer = dest->bufsize;
 718 }
 719
 720 static jboolean JPEG_Mem_EmptyOutputBuffer (j_compress_ptr cinfo)
 721 {
 722         error_in_jpeg = true;
 723         return false;
 724 }
 725
 726 static void JPEG_Mem_TermDestination (j_compress_ptr cinfo)
 727 {
 728         my_dest_ptr dest = (my_dest_ptr)cinfo->dest;
 729         dest->bufsize = dest->pub.next_output_byte - dest->buffer;
 730 }
 731 static void JPEG_MemDest (j_compress_ptr cinfo, void* buf, size_t bufsize)
 732 {
 733         my_dest_ptr dest;
 734
 735         // First time for this JPEG object?
 736         if (cinfo->dest == NULL)
 737                 cinfo->dest = (struct jpeg_destination_mgr *)(*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_PERMANENT, sizeof(my_destination_mgr));
 738
 739         dest = (my_dest_ptr)cinfo->dest;
 740         dest->pub.init_destination = JPEG_Mem_InitDestination;
 741         dest->pub.empty_output_buffer = JPEG_Mem_EmptyOutputBuffer;
 742         dest->pub.term_destination = JPEG_Mem_TermDestination;
 743         dest->outfile = NULL;
 744
 745         dest->buffer = buf;
 746         dest->bufsize = bufsize;
 747 }
 748
 749
 750 /*
 751 ====================
 752 JPEG_SaveImage_preflipped
 753
 754 Save a preflipped JPEG image to a file
 755 ====================
 756 */
 757 qboolean JPEG_SaveImage_preflipped (const char *filename, int width, int height, unsigned char *data)
 758 {
 759         struct jpeg_compress_struct cinfo;
 760         struct jpeg_error_mgr jerr;
 761         unsigned char *scanline;
 762         unsigned int offset, linesize;
 763         qfile_t* file;
 764
 765         // No DLL = no JPEGs
 766         if (!jpeg_dll)
 767         {
 768                 Con_Print("You need the libjpeg library to save JPEG images\n");
 769                 return false;
 770         }
 771
 772         // Open the file
 773         file = FS_Open (filename, "wb", true, false);
 774         if (!file)
 775                 return false;
 776
 777         cinfo.err = qjpeg_std_error (&jerr);
 778         cinfo.err->error_exit = JPEG_ErrorExit;
 779         error_in_jpeg = false;
 780
 781         qjpeg_create_compress (&cinfo);
 782         JPEG_FileDest (&cinfo, file);
 783
 784         // Set the parameters for compression
 785         cinfo.image_width = width;
 786         cinfo.image_height = height;
 787         cinfo.in_color_space = JCS_RGB;
 788         cinfo.input_components = 3;
 789         qjpeg_set_defaults (&cinfo);
 790         qjpeg_set_quality (&cinfo, (int)(scr_screenshot_jpeg_quality.value * 100), TRUE);
 791
 792         // turn off subsampling (to make text look better)
 793         cinfo.optimize_coding = 1;
 794         cinfo.comp_info[0].h_samp_factor = 1;
 795         cinfo.comp_info[0].v_samp_factor = 1;
 796         cinfo.comp_info[1].h_samp_factor = 1;
 797         cinfo.comp_info[1].v_samp_factor = 1;
 798         cinfo.comp_info[2].h_samp_factor = 1;
 799         cinfo.comp_info[2].v_samp_factor = 1;
 800
 801         qjpeg_start_compress (&cinfo, true);
 802
 803         // Compress each scanline
 804         linesize = cinfo.image_width * 3;
 805         offset = linesize * (cinfo.image_height - 1);
 806         while (cinfo.next_scanline < cinfo.image_height)
 807         {
 808                 scanline = &data[offset - cinfo.next_scanline * linesize];
 809
 810                 qjpeg_write_scanlines (&cinfo, &scanline, 1);
 811                 if (error_in_jpeg)
 812                         break;
 813         }
 814
 815         qjpeg_finish_compress (&cinfo);
 816         qjpeg_destroy_compress (&cinfo);
 817
 818         FS_Close (file);
 819         return true;
 820 }
 821
 822 static size_t JPEG_try_SaveImage_to_Buffer (struct jpeg_compress_struct *cinfo, char *jpegbuf, size_t jpegsize, int quality, int width, int height, unsigned char *data)
 823 {
 824         unsigned char *scanline;
 825         unsigned int linesize;
 826         int offset;
 827
 828         error_in_jpeg = false;
 829
 830         JPEG_MemDest (cinfo, jpegbuf, jpegsize);
 831
 832         // Set the parameters for compression
 833         cinfo->image_width = width;
 834         cinfo->image_height = height;
 835         cinfo->in_color_space = JCS_RGB;
 836         cinfo->input_components = 3;
 837         qjpeg_set_defaults (cinfo);
 838         qjpeg_set_quality (cinfo, quality, FALSE);
 839
 840         cinfo->comp_info[0].h_samp_factor = 2;
 841         cinfo->comp_info[0].v_samp_factor = 2;
 842         cinfo->comp_info[1].h_samp_factor = 1;
 843         cinfo->comp_info[1].v_samp_factor = 1;
 844         cinfo->comp_info[2].h_samp_factor = 1;
 845         cinfo->comp_info[2].v_samp_factor = 1;
 846         cinfo->optimize_coding = 1;
 847
 848         qjpeg_start_compress (cinfo, true);
 849
 850         // Compress each scanline
 851         linesize = width * 3;
 852         offset = linesize * (cinfo->image_height - 1);
 853         while (cinfo->next_scanline < cinfo->image_height)
 854         {
 855                 scanline = &data[offset - cinfo->next_scanline * linesize];
 856
 857                 qjpeg_write_scanlines (cinfo, &scanline, 1);
 858                 if (error_in_jpeg)
 859                         break;
 860         }
 861
 862         qjpeg_finish_compress (cinfo);
 863
 864         return error_in_jpeg ? 0 : ((my_dest_ptr) cinfo->dest)->bufsize;
 865 }
 866
 867 size_t JPEG_SaveImage_to_Buffer (char *jpegbuf, size_t jpegsize, int width, int height, unsigned char *data)
 868 {
 869         struct jpeg_compress_struct cinfo;
 870         struct jpeg_error_mgr jerr;
 871
 872         int quality;
 873         int quality_guess;
 874         size_t result;
 875
 876         // No DLL = no JPEGs
 877         if (!jpeg_dll)
 878         {
 879                 Con_Print("You need the libjpeg library to save JPEG images\n");
 880                 return false;
 881         }
 882
 883         cinfo.err = qjpeg_std_error (&jerr);
 884         cinfo.err->error_exit = JPEG_ErrorExit;
 885
 886         qjpeg_create_compress (&cinfo);
 887
 888 #if 0
 889         // used to get the formula below
 890         {
 891                 char buf[1048576];
 892                 unsigned char *img;
 893                 int i;
 894
 895                 img = Mem_Alloc(tempmempool, width * height * 3);
 896                 for(i = 0; i < width * height * 3; ++i)
 897                         img[i] = rand() & 0xFF;
 898
 899                 for(i = 0; i <= 100; ++i)
 900                 {
 901                         Con_Printf("! %d %d %d %d\n", width, height, i, (int) JPEG_try_SaveImage_to_Buffer(&cinfo, buf, sizeof(buf), i, width, height, img));
 902                 }
 903
 904                 Mem_Free(img);
 905         }
 906 #endif
 907
 908         //quality_guess = (100 * jpegsize - 41000) / (width*height) + 2; // fits random data
 909         quality_guess   = (256 * jpegsize - 81920) / (width*height) - 8; // fits Nexuiz's map pictures
 910
 911         quality_guess = bound(0, quality_guess, 90);
 912         quality = quality_guess + 10; // assume it can do 10 failed attempts
 913
 914         while(!(result = JPEG_try_SaveImage_to_Buffer(&cinfo, jpegbuf, jpegsize, quality, width, height, data)))
 915         {
 916                 --quality;
 917                 if(quality < 0)
 918                 {
 919                         Con_Printf("couldn't write image at all, probably too big\n");
 920                         return 0;
 921                 }
 922         }
 923         Con_DPrintf("JPEG_SaveImage_to_Buffer: guessed quality/size %d/%d, actually got %d/%d\n", quality_guess, (int)jpegsize, quality, (int)result);
 924
 925         return result;
 926 }
 927
 928 typedef struct CompressedImageCacheItem
 929 {
 930         char imagename[MAX_QPATH];
 931         size_t maxsize;
 932         void *compressed;
 933         size_t compressed_size;
 934         struct CompressedImageCacheItem *next;
 935 }
 936 CompressedImageCacheItem;
 937 #define COMPRESSEDIMAGECACHE_SIZE 4096
 938 static CompressedImageCacheItem *CompressedImageCache[COMPRESSEDIMAGECACHE_SIZE];
 939
 940 static void CompressedImageCache_Add(const char *imagename, size_t maxsize, void *compressed, size_t compressed_size)
 941 {
 942         const char *hashkey = va("%s:%d", imagename, (int) maxsize);
 943         int hashindex = CRC_Block((unsigned char *) hashkey, strlen(hashkey)) % COMPRESSEDIMAGECACHE_SIZE;
 944         CompressedImageCacheItem *i;
 945
 946         if(strlen(imagename) >= MAX_QPATH)
 947                 return; // can't add this
 948
 949         i = Z_Malloc(sizeof(CompressedImageCacheItem));
 950         strlcpy(i->imagename, imagename, sizeof(i->imagename));
 951         i->maxsize = maxsize;
 952         i->compressed = compressed;
 953         i->compressed_size = compressed_size;
 954         i->next = CompressedImageCache[hashindex];
 955         CompressedImageCache[hashindex] = i;
 956 }
 957
 958 static CompressedImageCacheItem *CompressedImageCache_Find(const char *imagename, size_t maxsize)
 959 {
 960         const char *hashkey = va("%s:%d", imagename, (int) maxsize);
 961         int hashindex = CRC_Block((unsigned char *) hashkey, strlen(hashkey)) % COMPRESSEDIMAGECACHE_SIZE;
 962         CompressedImageCacheItem *i = CompressedImageCache[hashindex];
 963
 964         while(i)
 965         {
 966                 if(i->maxsize == maxsize)
 967                         if(!strcmp(i->imagename, imagename))
 968                                 return i;
 969         }
 970         return NULL;
 971 }
 972
 973 qboolean Image_Compress(const char *imagename, size_t maxsize, void **buf, size_t *size)
 974 {
 975         unsigned char *imagedata, *newimagedata;
 976         int maxPixelCount;
 977         int components[3] = {2, 1, 0};
 978         CompressedImageCacheItem *i;
 979
 980         JPEG_OpenLibrary (); // for now; LH had the idea of replacing this by a better format
 981
 982         // No DLL = no JPEGs
 983         if (!jpeg_dll)
 984         {
 985                 Con_Print("You need the libjpeg library to save JPEG images\n");
 986                 return false;
 987         }
 988
 989         i = CompressedImageCache_Find(imagename, maxsize);
 990         if(i)
 991         {
 992                 *size = i->compressed_size;
 993                 *buf = i->compressed;
 994         }
 995
 996         // load the image
 997         imagedata = loadimagepixelsbgra(imagename, true, false);
 998         if(!imagedata)
 999                 return false;
1000
1001         // find an appropriate size for somewhat okay compression
1002         if(maxsize <= 768)
1003                 maxPixelCount = 32 * 32;
1004         else if(maxsize <= 1024)
1005                 maxPixelCount = 64 * 64;
1006         else if(maxsize <= 4096)
1007                 maxPixelCount = 128 * 128;
1008         else
1009                 maxPixelCount = 256 * 256;
1010
1011         while(image_width * image_height > maxPixelCount)
1012         {
1013                 int one = 1;
1014                 Image_MipReduce32(imagedata, imagedata, &image_width, &image_height, &one, image_width/2, image_height/2, 1);
1015         }
1016
1017         newimagedata = Mem_Alloc(tempmempool, image_width * image_height * 3);
1018
1019         // convert the image from BGRA to RGB
1020         Image_CopyMux(newimagedata, imagedata, image_width, image_height, false, false, false, 3, 4, components);
1021         Mem_Free(imagedata);
1022
1023         // try to compress it to JPEG
1024         *buf = Z_Malloc(maxsize);
1025         *size = JPEG_SaveImage_to_Buffer(*buf, maxsize, image_width, image_height, newimagedata);
1026         if(!*size)
1027         {
1028                 Z_Free(*buf);
1029                 *buf = NULL;
1030                 Con_Printf("could not compress image %s to %d bytes\n", imagename, (int)maxsize);
1031                 // return false;
1032                 // also cache failures!
1033         }
1034
1035         // store it in the cache
1036         CompressedImageCache_Add(imagename, maxsize, *buf, *size);
1037         return (*buf != NULL);
1038 }