galfar.imaginglib/Doc/VampyreDoc/FileFormats/ElderImagery.xml

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<doc>
  <title>Elder Imagery</title>
  <chapter>
    <title>Elder Imagery</title>
    <par>
      Elder Imagery is extension for Vampyre Imaging Library that
      adds support for loading and saving of images and textures from older
      Bethesda games like Redguard, BatteSpire,
      Terminator: FS, and TES: Arena, but mostly for
      The Elder Scrolls 2: Daggerfall (loads all images and textures
      from this game). All formats are 8bit indexed images (plus some 16bit color
      mapping in Battlespire) and palettes are often external.
      Default palettes for most images of each game are included in Elder Imagery
      but there are usually few images that use others (you can load them manually
      and assign them to loader class). Elder Imagery extension resides in
      <keyword>Extras</keyword> package.
      Here is the list of file formats supported by Elder Imagery:
    </par>
    
    <blist>
      <li>
        <keyword>IMG - Daggerfall Image</keyword>
        is 8 bit indexed format found in Daggerfall, Arena, Terminator: FS,
        and maybe other old Bethesda games. Files can be RLE compressed
        and may contain palette although most images use external palettes.
        Some files have no header at all so exact file size must be known
        prior to loading (otherwise no-header files wont be recognized or whole
        image could be identified as CIF as they use the same header).
      </li>
      <li>
        <keyword>CIF - Daggerfall MultiImage</keyword>
        is basically a sequence of images in IMG images stored in one file
        (with exception of Weapo*.cif files which are little bit more complex).
        As with IMG files CIF files can be RLE compressed and there are
        also special CIFs without header.
        Total number of frames in file is known after the whole file was parsed
        so exact file size must be known prior to loading.
      </li>
      <li>
        <keyword>TEXTURE - Daggerfall Texture</keyword>
        is format for texture storage in TES2: Daggerfall
        (works for Terminator: FS and maybe other games too).
        Textures are stored in 8bit indexed format with external palette.
        This format is very complicated (more images with subimages,
        nonstandard RLE, many unknowns) so only loading is supported.
        These texture files cannot be recognized by filename extension because
        their filenames are in form texture.### where # is number. Use filename
        masks instead.
      </li>
      <li>
        <keyword>BSI - Bethesda Image</keyword>
        is format for textures and images found
        in Redguard and BattleSpire (maybe in other games too, Skynet?). This format
        uses chunk structure similar to PNG (HDR/DAT/END). Redguard stores
        multiple images in one file (usually related like textures for various
        parts of single 3d object). Image data is stored as 8bit. Each image
        can have its own embedded palette or it can use external default palette.
        BattleSpire BSI use *.bsi file extension whilst Redguard uses
        texbsi.* mask with number extension (just like Daggerfall).
        Only loading is supported for this format.
        BattleSpire images also contain some sort of 8bit->16bit color mapping data
        which I've not yet figured out (only blue channel known) so
        don't expect to get pretty results from it now.
      </li>
      <li>
        <keyword>SKY - Daggerfall Sky Images</keyword>
        are used as backdrops in outdoor areas. There's about 200MB of 
        sky images in Daggerfall installation. Each sky file (sky##.dat)
        contains 64 images 512x220 pixels each. Images in one file 
        are for one climate zone and each is used for certain time of the day.
      </li>
    </blist>

    <note>
      When saving image in IMG or CIF format it gets converted to 8bit indexed
      format and mapped to current palette set in saver class. Also note
      that max size (in bytes) of image that can be saved is 65535 bytes
      (it is resized automatically if bigger).
    </note>
    
    <note>
      Since most people won't need support for these formats they are disabled
      by default (not compiled into your binary).    
      If you want them go to <ref>ImagingExtras.pas</ref> unit
      and comment out or delete <icode>{$DEFINE DONT_LINK_ELDER}</icode>
      line.
    </note>
    
  </chapter>
</doc>