Editing Blood Omen file formats

{{TOCRIGHT}}
This page is dedicated to the specifications for file formats used in Blood Omen. It encompasses exploring work done by the community since Blood Omen was released. 

Most simple formats (such as .BIG file structure, TIM specs) were unveiled long time ago, but some ones (map format, sprites) was unveiled lately during [[Blood Pill]] development.

==BIG file==
This is general file storing all game resources. It's structure is quite simple:

 '''uint32''' - number of entries
 <span style="color:green">Array of entries:</span>
   '''uint32''' - Hashed name of file
   '''uint32''' - File size
   '''uint32''' - File offset
 <span style="color:green">Array of entry data:</span>
   '''bytes''' - File contents

{{tip|There can be gaps between files}}

==TIM image==
Playstation images. Used to store graphics and tiles. TIM specs are widely known, so it will be not listed here. Reference decoder/encoder can be found [https://github.com/paulvortex/BloodPill/blob/master/src/timfile.cpp here].

'''Tips''':
* Some pill.big entries can contain several TIM's glued together.
* Some blood omen TIM files can contain tails with nulls.

==Sounds==

===VAG===
Playstation's Very-Audio-Good files (4-bit ADPCM variation) used in blood omen playstation version and by blood omen sneak peek preview. Unused in PC version. Reference decoder/encoder can be found [https://github.com/paulvortex/BloodPill/blob/master/src/vagfile.cpp here].

'''Tips''':
* Many VAG files are headerless (having mess in the header, even no 'VAGb' fourCC, hence could only be detected by direct parsing).
* Normally should be played at 11025hz, but some ones (music and some sounds) at 22050hz

===RAW IMA ADPCM===
Headerless files containing raw IMA ADPCM stream to replaces VAG files in PC version. They are using exactly same file names as VAG files in playstation version.

{{tip|Files have no header at all}}

===Waveform Audio File===
Blood Omen PC version have some sounds in .WAV format (playstation have them in .VAG). This format is widely known and does not need to be explained.

{{tip|It seems game doesnt use WAV headers, some file have bogus play rate and should be tweaked manually to play with correct rate thay listened in game}}

==Video==

===PSX STR===
Used in Blood Omen PlayStation version. STR is MJPEG video stream with interleaved audio. [http://kenai.com/projects/jpsxdec/pages/Home jPsxDec] tool could be used to extract and decode this format from playstation CD images.

===JAM Videos===
JAM is lossy video compression format developed by Semilogic entertainment and used in Blood Omen PC version. The format uses shared palette for several frames and a form of dynamic compression. JAM spec and decoder was unveiled in 2011 by MisterGrim. JAM can only store video, audio was stored in separate .VAG file (which was for real, raw IMA ADPCM).

JAM videos have much more artifacts than STR, sound track is mono (STR have stereo).

JAM decompressing code can be found [https://github.com/paulvortex/BloodPill/blob/master/src/jamfile.cpp here]

==Sprites==

Sprites are images of characters and animated stuff. There are 3 extensions as of filenames: SHA, SDR, SHD. However, when Blood Pill was developed, there were no knowledge of real file names, so this spec will define "Sprite types" which covers unpacking of all sprites, including unused ones.

===Sprite type 1 - Item Cards===
Always have 1 frame and no compression used. 

 '''uint32''' - always 0x01 0x00 0x00 0x00 
 '''uint32''' - file size
 '''768 bytes''' - 24-bit colormap data (256 colors)
 '''int16''' - x position
 '''int16''' - y position
 '''byte''' - width
 '''byte''' - height
 '''byte''' - x
 '''byte''' - y
 '''width*height bytes''' - picture contents (indexes into colormap)

{{tip|Really, it is simplified sprite type 3}}

===Sprite type 2 - Images collection===
Multiframe sprite with per-frame palette. Used by interface images collections (such as spell/item pics).

 '''uint32''' - number of frames
 '''uint32''' - file size
 '''768 bytes''' - 24-bit colormap data (unused)
 <span style="color:green">Array of frame headers:</span>
   '''768 bytes''' - 24-bit colormap data
   '''uint32''' - offset to the picture data from the end of headers
   '''ubyte''' - width
   '''ubyte''' - height
   '''byte''' - x
   '''byte''' - y
 <span style="color:green">Array of frame picture data:</span>
   '''width*height bytes''' - picture contents (indexes into colormap)

{{tip|In some files real width/height may be double of what written in header}}

===Sprite type 3 - Object sprites===
Multiframe sprite with shared palette.

 '''uint32''' - number of frames
 '''uint32''' - file size
 '''768 bytes''' - 24-bit colormap data
 '''int16''' - x offset for all frames
 '''int16''' - y offset for all frames
 <span style="color:green">Array of frame headers:</span>
   '''uint32''' - offset to the picture data from the end of headers
   '''ubyte''' - width
   '''ubyte''' - height
   '''byte''' - x
   '''byte''' - y
 <span style="color:green">Array of frame picture data:</span>
   '''bytes''' - compressed picture contents (indexes into colormap) using run-length encodingE, some files using 4-bit color (see [[#Compression methods]])

'''Tips''':
* It is unknown how to get what compression file do use (RLE on 0x00, or 0xFF or both), it seems engine gives that info when file get loaded
* Some files are using 4-bit color instead of RLE

===Sprite type 4 - character sprites===
Multiframe sprite with shared palette, with additional frames headers. Used by characters. Pretty same as type 3.

 '''uint32''' - number of frames
 '''uint32''' - file size
 <span style="color:green">Array of additional frame headers (rounded to the greatest multiplier of 4):</span>
    '''byte''' - damage mark. A value of 1 tell the game to deal damage in this frame.
 '''768 bytes''' - 24-bit colormap data
 '''int16''' - x offset for all frames
 '''int16''' - y offset for all frames
 <span style="color:green">Array of frame headers:</span>
   '''uint32''' - offset to the picture data from the end of headers
   '''ubyte''' - width
   '''ubyte''' - height
   '''byte''' - x
   '''byte''' - y
 <span style="color:green">Array of frame picture data:</span>
   '''bytes''' - compressed picture contents (indexes into colormap) using run-length encoding, some files using 4-bit color (see [[#Compression methods]])

'''Tips''':
* It is unknown how to get what compression file do use (RLE on 0x00, or 0xFF or both), it seems engine gives that info when file get loaded
* Some files are using 4-bit color instead of RLE

===Sprite type 5===
Another variation of type 3 with no offset info and (sometimes) broken width/height, which should be fixed with special trick.

 '''uint32''' - number of frames
 '''uint32''' - file size
 '''768 bytes''' - 24-bit colormap data
 <span style="color:green">Array of frame headers:</span>
   '''uint32''' - offset to the picture data from the end of headers
   '''ubyte''' - width
   '''ubyte''' - height
   '''byte''' - x
   '''byte''' - y
 <span style="color:green">Array of frame picture data:</span>
   '''bytes''' - compressed picture contents (indexes into colormap) using RLE  (see [[#Compression methods]])

'''Tips''':
* Some frames have broken width/height because they width is above 255 and format uses 1 byte to encode it, 255 + [width] should be used to correct this
* It is unknown how to get what compression file do use (RLE on 0x00, or 0xFF or both), it seems engine gives that info when file get loaded

==Maps==

Maps are central thing which brings all resources (images, sounds, tiles, sprites) together. There is about 80% of map structure revealed, allowing to extract general amount of things from it, including: textures used, a map image, monster/effect/item placement, triggers, info marks, doors and buttons etc.

Each map has a mapnum and section that is included in filename. That info is used to place map in a global adventure map (see [http://www.thelostworlds.net/BO1/Map_Survey.html TheLost Worlds - May survey] for complete info about level naming).

=== Tiles ===
Tiles are 256-color TIM images compressed with LZ77 (see [[#Compression methods]]).

Each tile texture has 8x8 = 64 tiles. Engine renders all tile separately, switching current tile texture as needed.

 '''uint32''' - compressed data size
 '''bytes''' - compressed data

'''Tips''':
* Since all tiles are 8-bit 256x256 TIM, unpacked data size is always same

=== Map file ===

Map file is fixed-length structure which holds tiles placement (80x80), enemies, lights, buttons and other objects to form Blood Omen level. Because of it's fixed nature, there are many limits, and each map file have exactly same size (so it can just be copied into memory).

 <span style="color:green">// map trigger</span>
 <span style="color:darkblue">typedef struct</span> 
 <span style="color:darkblue">'''{'''</span>
      '''unsigned short''' parm1;    <span style="color:green">// first parm, if script is not defined it's 0xFFFF, 0xFFFE is null value</span>
                               <span style="color:green">//  - destination/source map number (TRIGGER_EXIT, TRIGGER_ENTRANCE, TRIGGER_TELEPORT)</span>
                               <span style="color:green">//  - speech num (TRIGGER_INFOMARK, TRIGGER_IMAGEMARK)</span>
      '''unsigned short''' parm2;    <span style="color:green">// second parm:</span>
                               <span style="color:green">//  - button num (TRIGGER_BUTTON)</span>
                               <span style="color:green">//  - pic num (TRIGGER_IMAGEMARK)</span>
      '''byte'''           parm3;    <span style="color:green">// destination/source map section (TRIGGER_EXIT, TRIGGER_ENTRANCE, TRIGGER_TELEPORT)</span>
      '''byte'''           srcx;     <span style="color:green">// sposition</span>
      '''byte'''           srcy;     <span style="color:green">// sposition</span>
      '''byte'''           type;     <span style="color:green">// script type, one of TRIGGER_</span>
      '''byte'''           u2<span style="color:darkblue">'''['''</span>3<span style="color:darkblue">''']'''</span>;    <span style="color:green">// ?</span>
      '''byte'''           x;        <span style="color:green">// position</span>
      '''byte'''           y;        <span style="color:green">// position</span>
      '''byte'''           u3<span style="color:darkblue">'''['''</span>3<span style="color:darkblue">''']'''</span>;    <span style="color:green">// ?</span>
 <span style="color:darkblue">'''}'''</span>'''bo_trigger_t''';
 
 <span style="color:green">// map item</span>
 <span style="color:darkblue">typedef struct</span>
 <span style="color:darkblue">'''{'''</span>
      '''unsigned short''' savenum;  <span style="color:green">// unique savegame id</span>
      '''byte'''           itemcode; <span style="color:green">// one of MAPITEM_ code</span>
      '''byte'''           x;        <span style="color:green">// position</span>
      '''byte'''           y;        <span style="color:green">// position</span>
      '''byte'''           hidden;   <span style="color:green">// set to 1 if item is spawned by trigger (like barrel destruction)</span>
      '''unsigned short''' target;   <span style="color:green">// targeted triggergroup</span>
      '''byte'''           u<span style="color:darkblue">'''['''</span>4<span style="color:darkblue">''']'''</span>;     <span style="color:green">// ?</span>
 <span style="color:darkblue">'''}'''</span>'''bo_item_t''';
 
 <span style="color:green">// animated tile</span>
 <span style="color:darkblue">typedef struct</span>
 <span style="color:darkblue">'''{'''</span>
      '''unsigned short''' targetnum;<span style="color:green">// a triggergroup</span>
      '''byte''' x;                  <span style="color:green">// position</span>
      '''byte''' u1;                 <span style="color:green">// ?</span>
      '''byte''' y;                  <span style="color:green">// position</span>
      '''byte''' u2;                 <span style="color:green">// ?</span>
      '''unsigned short''' tile1;    <span style="color:green">// tilenum</span>
      '''unsigned short''' tile2;    <span style="color:green">// alternate state tilenum</span>
      '''byte''' contents1;          <span style="color:green">// contents, see CONTENTS_ defines for possible content values</span>
      '''byte''' contents2;          <span style="color:green">// alternate state contents</span>
      '''byte''' u3<span style="color:darkblue">'''['''</span>12<span style="color:darkblue">''']'''</span>;             <span style="color:green">// ?</span>
 <span style="color:darkblue">'''}'''</span>'''bo_atile_t''';
 
 <span style="color:green">// button controller</span>
 <span style="color:darkblue">typedef struct</span>
 <span style="color:darkblue">'''{'''</span>
      '''unsigned short''' target;   <span style="color:green">// a triggergroup to call</span>
      '''unsigned short''' tile1;    <span style="color:green">// tilenum</span>
      '''unsigned short''' tile2;    <span style="color:green">// alternate state tilenum</span>
      '''byte''' flags;              <span style="color:green">// see BUTTONFLAG_* defs</span>
      '''byte''' u1;                 <span style="color:green">// ?</span>
      '''unsigned short''' savenum;  <span style="color:green">// unique savegame id</span>
      '''byte''' u2;                 <span style="color:green">// ?</span>
      '''byte''' u3;                 <span style="color:green">// ?</span>
 <span style="color:darkblue">'''}'''</span>'''bo_button_t''';
 
 <span style="color:green">// effect</span>
 <span style="color:darkblue">typedef struct</span>
 <span style="color:darkblue">'''{'''</span>
      '''byte''' x;                  <span style="color:green">// position</span>
      '''byte''' y;                  <span style="color:green">// position</span>
      '''byte''' lightposx;          <span style="color:green">// position of lightsource</span>
      '''byte''' lightposy;          <span style="color:green">// position of lightsource</span>
      '''byte''' sprite;             <span style="color:green">// index of sprite from sprites array</span>
      '''byte''' lightsizex;         <span style="color:green">// size of light polygons</span>
      '''byte''' lightsizey;         <span style="color:green">// size of light polygons</span>
      '''byte''' u1;                 <span style="color:green">// ?</span>
      '''byte''' lightform;          <span style="color:green">// light form flags</span>
      '''byte''' r;                  <span style="color:green">// red color component</span>
      '''byte''' g;                  <span style="color:green">// green color component</span>
      '''byte''' b;                  <span style="color:green">// darkblue color component</span>
      '''unsigned short''' targetnum;<span style="color:green">// triggergroup</span>
      '''byte''' start_on;           <span style="color:green">// 1 if effect starts on, 0 if starts off</span>
      '''byte''' u3<span style="color:darkblue">'''['''</span>5<span style="color:darkblue">''']'''</span>;              <span style="color:green">// ?</span>
 <span style="color:darkblue">'''}'''</span>'''bo_effect_t''';
 
 <span style="color:darkblue">typedef struct</span>
 <span style="color:darkblue">'''{'''</span>
      '''byte''' data<span style="color:darkblue">'''['''</span>164<span style="color:darkblue">''']'''</span>;
 <span style="color:darkblue">'''}'''</span>'''bo_object_t''';
 
 <span style="color:green">// tile object definition (barrels, chests)</span>
 <span style="color:darkblue">typedef struct</span>
 <span style="color:darkblue">'''{'''</span>
      '''byte''' x;                  <span style="color:green">// start position</span>
      '''byte''' y;                  <span style="color:green">// end position</span>
      '''byte''' w;                  <span style="color:green">// width</span>
      '''byte''' h;                  <span style="color:green">// height</span>
      '''byte''' ofsx;               <span style="color:green">// multiply by 16 to get real offset</span>
      '''byte''' ofsy;               <span style="color:green">// multiply by 16 to get real offset</span>
      '''byte''' u1;
      '''byte''' u2;
 <span style="color:darkblue">'''}'''</span>'''bo_grpobject_t''';
 
 <span style="color:green">// scenery entities</span>
 <span style="color:darkblue">typedef struct</span>
 <span style="color:darkblue">'''{'''</span>
      '''byte''' u1;                 <span style="color:green">// ?</span>
      '''byte''' u2;                 <span style="color:green">// ?</span>
      '''byte''' u3;                 <span style="color:green">// ?</span>
      '''byte''' u4;                 <span style="color:green">// ?</span>
      '''unsigned short''' tile1;    <span style="color:green">// base tile (grpobject really, not standart 32x32 tile)</span>
      '''unsigned short''' tile2;    <span style="color:green">// toggled tile (grpobject)</span>
      '''unsigned short''' tile3;    <span style="color:green">// destroyed tilee (grpobject)</span>
      '''byte''' u5;                 <span style="color:green">// ?</span>
      '''byte''' u6;                 <span style="color:green">// ?</span>
      '''byte''' pushable;           <span style="color:green">// a strength required to push</span>
      '''byte''' toggled;            <span style="color:green">// trigger can toggle it's state (means tile2 is there)</span>
      '''byte''' u7;                 <span style="color:green">// ?</span>
      '''byte''' spawnitems<span style="color:darkblue">'''['''</span>3<span style="color:darkblue">''']'''</span>;      <span style="color:green">// item codes to spawn when toggled/destroyed</span>
      '''byte''' u8;                 <span style="color:green">// ?</span>
      '''byte''' destructible;       <span style="color:green">// destructible flags</span>
      '''unsigned short''' savenum;  <span style="color:green">// unique savegame id</span>
      '''byte''' u10;                <span style="color:green">// ?</span>
      '''byte''' x;                  <span style="color:green">// position</span>
      '''byte''' y;                  <span style="color:green">// position</span>
      '''byte''' u11;                <span style="color:green">// ? </span>
      '''byte''' active;             <span style="color:green">// 1 is filled, otherwise 0</span>
      '''byte''' u13;                <span style="color:green">// ? </span>
 <span style="color:darkblue">'''}'''</span>'''bo_scenery_t''';
 
 <span style="color:green">// enemy paths</span>
 <span style="color:darkblue">typedef struct</span>
 <span style="color:darkblue">'''{'''</span>
      '''byte''' x;                  <span style="color:green">// position</span>
      '''byte''' y;                  <span style="color:green">// position</span>
      '''byte''' u1;                 <span style="color:green">// ?</span>
      '''byte''' u2;                 <span style="color:green">// ?</span>
 <span style="color:darkblue">'''}'''</span>'''bo_path_t''';
 
 <span style="color:green">// enemy entity</span>
 <span style="color:darkblue">typedef struct</span>
 <span style="color:darkblue">'''{'''</span>
      bo_path_t paths<span style="color:darkblue">'''['''</span>4<span style="color:darkblue">''']'''</span>;      <span style="color:green">// patrole paths</span>
      '''byte''' u1<span style="color:darkblue">'''['''</span>12<span style="color:darkblue">''']'''</span>;             <span style="color:green">// ?</span>
      '''unsigned short''' savenum;  <span style="color:green">// unique savegame id</span>
      '''byte''' u2<span style="color:darkblue">'''['''</span>52<span style="color:darkblue">''']'''</span>;             <span style="color:green">// ?</span>
      '''byte''' charnum;            <span style="color:green">// monster class (same as char* sprite)</span>
      '''byte''' u3<span style="color:darkblue">'''['''</span>10<span style="color:darkblue">''']'''</span>;             <span style="color:green">// ?</span>
      '''unsigned short''' target;   <span style="color:green">// triggergroup to call once killed</span>
      '''byte''' u4<span style="color:darkblue">'''['''</span>20<span style="color:darkblue">''']'''</span>;             <span style="color:green">// ?</span>
      '''byte''' lastpath;           <span style="color:green">// ?</span>
      '''byte''' u6<span style="color:darkblue">'''['''</span>18<span style="color:darkblue">''']'''</span>;             <span style="color:green">// ?</span>
      '''byte''' u7<span style="color:darkblue">'''['''</span>15<span style="color:darkblue">''']'''</span>;             <span style="color:green">// ?</span>
      '''byte''' x;                  <span style="color:green">// position</span>
      '''byte''' y;                  <span style="color:green">// position</span>
      '''byte''' u8<span style="color:darkblue">'''['''</span>4<span style="color:darkblue">''']'''</span>;              <span style="color:green">// ?</span>
      '''unsigned short''' speechnum;<span style="color:green">// a speech number for disguise talk</span>
      '''byte''' u9<span style="color:darkblue">'''['''</span>6<span style="color:darkblue">''']'''</span>;              <span style="color:green">// ?</span>
 <span style="color:darkblue">'''}'''</span>'''bo_monster_t''';
 
 <span style="color:green">// general map file structure</span>
 <span style="color:darkblue">typedef struct</span>
 <span style="color:darkblue">'''{'''</span>
      <span style="color:green">// a chain of tilemap numbers used (to make a filenames)</span>
      <span style="color:green">// each tilemap holds 64 tiles, tiles numbering is linear</span>
      <span style="color:green">// like, a tile #131 is tile #3 from tilemap #2</span>
      <span style="color:green">// being 2-'''byte''' ('''unsigned short''') tilenum contains some flags (flag are starting from '''byte''' 10)</span>
      <span style="color:green">// see TILEFLAG_ defines for possible tileflags</span>
      '''unsigned short'''  tilemaps<span style="color:darkblue">'''['''</span>40<span style="color:darkblue">''']'''</span>;
      <span style="color:green">// yet unknown info</span>
      '''byte'''            u1<span style="color:darkblue">'''['''</span>12<span style="color:darkblue">''']'''</span>;
      '''bo_object_t'''     objects<span style="color:darkblue">'''['''</span>10<span style="color:darkblue">''']'''</span>;
      '''bo_monster_t'''    monsters<span style="color:darkblue">'''['''</span>32<span style="color:darkblue">''']'''</span>;
      '''bo_grpobject_t'''  grpobjects<span style="color:darkblue">'''['''</span>8<span style="color:darkblue">''']'''</span><span style="color:darkblue">'''['''</span>32<span style="color:darkblue">''']'''</span>;
      <span style="color:green">// animated tiles - a tiles that can be toggled between 2 states and have different contents for each state</span>
      <span style="color:green">// used on doors, spikes that pops up on the floor etc.</span>
      <span style="color:green">// animated tiles have triggergroup to be executed by script</span>
      '''bo_atile_t'''      atiles<span style="color:darkblue">'''['''</span>100<span style="color:darkblue">''']'''</span>;
      <span style="color:green">// a special buttons array holds all buttons used on level</span>
      <span style="color:green">// pretty similar to animated tiles</span>
      <span style="color:green">// buttons have triggergroup to be executed by script</span>
      '''bo_button_t'''     buttons<span style="color:darkblue">'''['''</span>20<span style="color:darkblue">''']'''</span>;
      <span style="color:green">// yet unknown info #2</span>
      '''byte'''            u2<span style="color:darkblue">'''['''</span>8<span style="color:darkblue">''']'''</span>;
      <span style="color:green">// scenery pushable objects - tables, chairs, stones etc.</span>
      '''bo_scenery_t'''    scenery<span style="color:darkblue">'''['''</span>256<span style="color:darkblue">''']'''</span>;
      <span style="color:green">// first tilemap</span>
      '''unsigned short'''  backtiles<span style="color:darkblue">'''['''</span>80<span style="color:darkblue">''']'''</span><span style="color:darkblue">'''['''</span>80<span style="color:darkblue">''']'''</span>;
      <span style="color:green">// second tilemap</span>
      '''unsigned short'''  foretiles<span style="color:darkblue">'''['''</span>80<span style="color:darkblue">''']'''</span><span style="color:darkblue">'''['''</span>80<span style="color:darkblue">''']'''</span>;
      <span style="color:green">// contents map - a contents value for each static tile (in game they get overriden by switchable tiles if presented)</span>
      <span style="color:green">// see CONTENTS_ defines for possible content values</span>
      '''byte'''            contents<span style="color:darkblue">'''['''</span>80<span style="color:darkblue">''']'''</span><span style="color:darkblue">'''['''</span>80<span style="color:darkblue">''']'''</span>;
      <span style="color:green">// linear triggers array - all triggers used on map</span>
      '''bo_trigger_t'''    triggers<span style="color:darkblue">'''['''</span>255<span style="color:darkblue">''']'''</span>;
      <span style="color:green">// triggers are non-solid interaction points, activated when player stands in them</span>
      <span style="color:green">// this array golds pointers to triggers</span>
      '''byte'''            triggertiles<span style="color:darkblue">'''['''</span>80<span style="color:darkblue">''']'''</span><span style="color:darkblue">'''['''</span>80<span style="color:darkblue">''']'''</span>;
      <span style="color:green">// items placed on level</span>
      <span style="color:green">// itemcodes 0-9 are powerups, codes 10, 11, 12, 13 reserved for unique item codes</span>
      <span style="color:green">// so there will be not more than 4 unique item type per level</span>
      <span style="color:green">// unique items are: spells, weapons, forms, artifacts, tokens</span>
      '''byte'''            uniqueitems<span style="color:darkblue">'''['''</span>4<span style="color:darkblue">''']'''</span>;
      '''bo_item_t'''       items<span style="color:darkblue">'''['''</span>50<span style="color:darkblue">''']'''</span>;
      <span style="color:green">// yet unknown data</span>
      '''byte'''            u4<span style="color:darkblue">'''['''</span>8<span style="color:darkblue">''']'''</span>;
      '''byte'''            u5<span style="color:darkblue">'''['''</span>8<span style="color:darkblue">''']'''</span><span style="color:darkblue">'''['''</span>40<span style="color:darkblue">''']'''</span>;
      '''byte'''            u6<span style="color:darkblue">'''['''</span>24<span style="color:darkblue">''']'''</span>;
      <span style="color:green">// effects</span>
      '''unsigned short'''  sprites<span style="color:darkblue">'''['''</span>8<span style="color:darkblue">''']'''</span>;
      '''bo_effect_t'''     effects<span style="color:darkblue">'''['''</span>64<span style="color:darkblue">''']'''</span>;
      <span style="color:green">// yet unknown data</span>
      '''byte'''   u7<span style="color:darkblue">'''['''</span>936<span style="color:darkblue">''']'''</span>;
 <span style="color:darkblue">'''}'''</span>bo_map_t;
 
 <span style="color:green">// things that are not figured out yet:</span>
 <span style="color:green">// - how lightning is done (variable form lights, day-night light, ambient light)</span>
 <span style="color:green">// - monster's paths's switch (some paths are messed up)</span>
 <span style="color:green">// - counters and puzzle triggers?</span>
 
 <span style="color:green">// tileflags</span>
 #define '''TILEFLAG_UNKNOWN1'''       1024
 #define '''TILEFLAG_NODRAW'''         2048
 #define '''TILEFLAG_UNKNOWN3'''       4096
 #define '''TILEFLAG_UNKNOWN4'''       8192
 #define '''TILEFLAG_ALWAYSONTOP'''    16384
 #define '''TILEFLAG_UNKNOWN6'''       32768
 
 <span style="color:green">// contents</span>
 #define '''CONTENTS_SOLID'''          1
 #define '''CONTENTS_WATER'''          2
 #define '''CONTENTS_LAVA'''           3
 #define '''CONTENTS_FIRE'''           4
 #define '''CONTENTS_SPIKES'''         5
 #define '''CONTENTS_TRAPTELEPORT'''   6
 #define '''CONTENTS_JUMPWALL'''       8
 #define '''CONTENTS_SWAMP'''          11
 #define '''CONTENTS_JUMPFENCE'''      10
 #define '''CONTENTS_MISTWALK'''       12
 #define '''CONTENTS_SACRIFICE'''      13
 #define '''CONTENTS_ICE'''            19
 #define '''CONTENTS_SAVEGAM'''        44
 #define '''CONTENTS_BATMARK'''        45
 
 <span style="color:green">// triggers</span>
 #define '''TRIGGER_EXIT'''            1
 #define '''TRIGGER_ENTRANCE'''        2
 #define '''TRIGGER_SPEECHMARK'''      3
 #define '''TRIGGER_TOUCH'''           4
 #define '''TRIGGER_TELEPORT'''        6
 #define '''TRIGGER_IMAGEMARK'''       7
 
 <span style="color:green">// button flags</span>
 #define '''BUTTONFLAG_TOGGLE'''       1
 #define '''BUTTONFLAG_SECRET'''       2
 
 <span style="color:green">// item codes</span>
 #define '''MAPITEM_SMALLBLOODFLASK''' 1
 #define '''MAPITEM_BLOODFLASK'''      2
 #define '''MAPITEM_RUNEPYRAMID'''     3
 #define '''MAPITEM_PURPLESPHERE'''    4
 #define '''MAPITEM_BLUESPHERE'''      5
 #define '''MAPITEM_GREENSPHERE'''     6
 #define '''MAPITEM_GOLDSPHERE'''      7
 #define '''MAPITEM_REDSPHERE'''       8
 #define '''MAPITEM_ANCIENTVIAL'''     9
 #define '''MAPITEM_UNIQUE1'''         10 <span style="color:green">// unique item codes</span>
 #define '''MAPITEM_UNIQUE2'''         11 <span style="color:green">// unique item codes</span>
 #define '''MAPITEM_UNIQUE3'''         12 <span style="color:green">// unique item codes</span>
 #define '''MAPITEM_UNIQUE4'''         13 <span style="color:green">// unique item codes</span>
 
 <span style="color:green">// unique item codes</span>
 #define '''ITEM_SPELL_INSPIREHATE'''  10
 #define '''ITEM_SPELL_STUN'''         11
 #define '''ITEM_SPELL_SPIRITWRACK'''  12
 #define '''ITEM_SPELL_BLOODGOUT'''    13
 #define '''ITEM_SPELL_BLOODSHOWER'''  14
 #define '''ITEM_SPELL_SPIRITDEATH'''  15
 #define '''ITEM_SPELL_LIGHT'''        16
 #define '''ITEM_SPELL_LIGHTNING'''    17
 #define '''ITEM_SPELL_REPEL'''        18
 #define '''ITEM_SPELL_ENERGYBOLT'''   19
 #define '''ITEM_SPELL_INCAPACITATE''' 20
 #define '''ITEM_SPELL_CONTROLMIND'''  21
 #define '''ITEM_SPELL_SANCTUARY'''    22
 #define '''ITEM_ARTIFACT_FLAY'''      23
 #define '''ITEM_ARTIFACT_PENTALICH''' 24
 #define '''ITEM_ARTIFACT_IMPLODE'''   25
 #define '''ITEM_ARTIFACT_FONT'''      26
 #define '''ITEM_ARTIFACT_BANK'''      27
 #define '''ITEM_ARTIFACT_HEART'''     28
 #define '''ITEM_ARTIFACT_ANTITOXIN''' 29
 #define '''ITEM_ARTIFACT_SLOWTIME'''  30
 #define '''ITEM_TOKEN_MOEBIUS'''      31
 #define '''ITEM_TOKEN_DEJOULE'''      32
 #define '''ITEM_TOKEN_DOLL'''         33
 #define '''ITEM_TOKEN_MALEK'''        34
 #define '''ITEM_TOKEN_AZIMUTH'''      35
 #define '''ITEM_TOKEN_MORTANIUS'''    36
 #define '''ITEM_TOKEN_NUPRAPTOR'''    37
 #define '''ITEM_TOKEN_BANE'''         38
 #define '''ITEM_TOKEN_SIGNETRING'''   39
 #define '''ITEM_TOKEN_TIMEDEVICE'''   40
 #define '''ITEM_TOKEN_ANACROTHE'''    41
 #define '''ITEM_WEAPON_MACE'''        43
 #define '''ITEM_WEAPON_AXES'''        44
 #define '''ITEM_WEAPON_FLAMESWORD'''  45
 #define '''ITEM_WEAPON_SOULREAVER'''  46
 #define '''ITEM_ARMOR_BONE'''         48
 #define '''ITEM_ARMOR_CHAOS'''        49
 #define '''ITEM_ARMOR_FLESH'''        50
 #define '''ITEM_ARMOR_WRAITH'''       51
 #define '''ITEM_FORM_BAT'''           53
 #define '''ITEM_FORM_WOLF'''          54
 #define '''ITEM_FORM_DISGUISE'''      55
 #define '''ITEM_FORM_MIST'''          56
 #define '''ITEM_ENDING_1'''           69
 #define '''ITEM_ENDING_2'''           70

==Compression methods==

'''Index-based Run Length Encoding (RLE)'''

Used on sprite data to compress black areas which is normally transparent. This technique alters reading process of byte 0x0 and 0xFF. If got this byte when reading picture data, should read 1 byte more which will be times to repeat this byte. Blood Omen RLE only used for values 0x00 or 0xFF.
    
Example: 

 <span style="color:green">// output 32 bytes with value 0xFF</span>
 0xFF 0x20

'''4-bit images'''

Encode 2 pixels per byte with 256 color palette but with only 16 colors used (other pixels are black).

For each byte it produces 2 bytes in order:
* byte 1 : <byte> - (int)(<byte>/16)*16; <span style="color:green">// <byte> mod 16</span>
* byte 2 : (int)(<byte>/16) <span style="color:green">// <byte> div 16</span>
  
Example:

  231 will output 2 pixels with values:
  byte 1 : 7
  byte 2 : 14

'''Variation of LZ77'''

A variation of the LZ77 (LZ1) data compression algorithms.

Sample decoder can be found at [http://www.thelostworlds.net/Software/Blood_Omen_Decompressor.html The Lost Worlds] and [[Blood Pill]] sourcecode.

==Credits==
* Andrey [Rackot] Grachev - Bigfile specs
* Pavel [VorteX] Timofeyev - Map file, sprites
* Ben Lincoln - LZ77 decompressor
* JAM decoding specs by MisterGrim
* Balder and Zench from XentaX forums (www.xentax.com) - IMA ADPCM

==See also==
* [[Blood Pill]]
* [http://kenai.com/projects/jpsxdec/pages/Home jPsxDec homepage]
* [http://wiki.qhimm.com/PSX/TIM_file TIM specifications at QHimmWiki]
* [http://www.thelostworlds.net/Software/Blood_Omen_Decompressor.html Blood Omen Decompressor homepage]
* [http://www.thelostworlds.net/BO1/Map_Survey.html Blood Omen Map Survey (TheLostWorlds)]

__NOEDITSECTION__ 
{{finished}}
{{grammar}}