--== READ ME ==--.txt
This script was designed to help me create patch textures of pure gore, that I could overlay on other textures in the patch editor or in Affinity. I can be used for more than that though.
It was designed to lift off blood, but was expanded to work on any colour
It has a number of ways to lift the blood colours from a texture and save into a PNG file with all the other colours as transparent.
You can also save the composite texture, as in all the other colours in the texture, with the chosen colours transparent.
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BLOODSPLIT v2.4
Lift blood / gore pixels off Doom textures onto transparent
truecolour PNGs. Scans a directory tree; writes results into a
mirrored structure under _BloodSplit, same filenames, always
RGBA PNG. Files with no blood are not written at all.
MODES (pick one; --doomMode is the default)
--doomMode [INDICES...]
exact match against the embedded Doom2 PLAYPAL -- no palette
file ever needed. Default set: the red ramp (176-191), which
is pure blood only. Widen with --wide or --allred, or take
full control by listing indices yourself (same syntax as
--paletteMode; overrides --wide/--allred):
bloodsplit --doomMode 16-47, 176-191, 66
-w, --wide
doomMode: add dried-blood/flesh reds and bright blood
highlights (indices 28-47, 173-175). ~39 colours.
-allred, --allred
doomMode: every blood-relevant colour in the Doom2 palette --
indices 16-47, 169-191, 232-235 (59 indices). Adds the pale
flesh-reds, pink highlights and dark scorched oranges that
--wide leaves behind. Catches the most gore; expect false
hits on flesh, fire and torch pixels. Supersedes --wide.
--paletteMode FILE INDICES...
exact match against the palette entries YOU list, from a
supplied palette file. Indices are singles and/or ranges,
comma or space separated: 124-138, 15, 10, 20-30
Duplicates and overlapping ranges are simply combined.
FILE formats: WAD (PLAYPAL found inside), raw .pal/lump,
JASC .pal, DoomTools playpal PNG (256 wide), SLADE pal0.png.
--colourMode [COLOURS...]
hue-family matching, no palette involved -- for truecolour
images or big-palette games (Hexen etc). Lifts every shade
of each base colour, bright to dark, ignoring other hues.
COLOURS: hex (no # needed) and/or names, one or several,
comma or space separated. A pixel matching ANY base is
lifted. Default: blood red.
Names: blue, brown, cyan, green, lime, magenta, orange, pink, purple, red, teal, violet, yellow
INPUT / OUTPUT
-i, --input DIR
directory to scan (recursive). Default: current directory.
-o, --output DIR
where the _BloodSplit dir is created. Default: current directory.
--ext png,bmp,...
image extensions to process. Default: png,bmp,gif,tga,jpg,jpeg.
TUNING
--tolerance N
colourMode master knob 0-100, default 25. Higher = wider hue
window and looser saturation floor, applied to every base
colour. Start here before touching the two overrides below.
--hue-tol X
colourMode override: hue window in degrees either side of each
base colour. (Default derives from --tolerance; 25 -> 14.)
--sat-min X
colourMode override: minimum saturation 0-1.
(Default derives from --tolerance; 25 -> 0.55.)
--softAlpha N
0-100 feather amount, default 0 (hard mask).
colourMode: borderline pixels fade in over an N%-wide band.
doom/paletteMode: blob edges are feathered by neighbourhood.
--saveCompositeFile
for every blood file written, also save NAME--composite.png:
the original image with the blood punched out to transparency.
With --softAlpha the composite gets the exact alpha complement,
so layering composite over blood rebuilds the original.
Saved next to the blood file, easy to eyeball-check.
--saveCompositeFileMoved
same, but composites go straight into
_BloodSplit\__CompositeFiles\... instead of next to the blood
files -- identical layout to running --moveComposite afterwards.
--moveComposite
standalone tidy-up, no image processing: move every file ending
--composite.png found under -i (subdirs included, _BloodSplit
trees included) into __CompositeFiles at -o, mirroring the
directory structure. Never looks inside __CompositeFiles, so
re-runs are safe; existing destination files are not overwritten.
--min-blob N
drop connected blood blobs smaller than N pixels. Default 3.
--min-pixels N
skip the file entirely if fewer than N blood pixels survive.
Default 8.
NOTES
- Mode and option names are matched case-insensitively.
- Existing transparency is preserved; transparent pixels are never blood.
- _BloodSplit directories are never scanned, so re-runs are safe.
- In doom/paletteMode, bloodless files that don't look palette-clean
trigger an end-of-run note suggesting --colourMode.
EXAMPLES
bloodsplit
scan current dir, doomMode red ramp, output to .\_BloodSplit
bloodsplit --allred
the widest doomMode net -- all 59 blood-relevant Doom2 indices
bloodsplit -i D:\tex\walls -o D:\out --wide
doomMode middle tier, output to D:\out\_BloodSplit
bloodsplit --doomMode 16-47, 169-191
explicit indices against the embedded Doom2 palette --
(--allred minus the 232-235 oranges, for example)
bloodsplit --paletteMode mypal.wad 124-138, 15, 10, 20-30
lift exactly those palette indices, palette pulled from the WAD
bloodsplit --colourMode
hue matching, default blood red -- for truecolour/Hexen images
bloodsplit --colourMode FF3700, FF000B, FF0058
several base colours at once; a pixel matching any is lifted
bloodsplit --colourMode green --tolerance 40
every shade of green (nukage?) with a looser match
bloodsplit --allred --saveCompositeFile
widest net, plus a --composite copy of each hit with the blood
punched out, saved next to the blood file
bloodsplit --allred --saveCompositeFileMoved
same, but composites land in _BloodSplit\__CompositeFiles\...
cd _BloodSplit && bloodsplit --moveComposite
after eyeball-checking: sweep the --composite.png files out of
the tree into _BloodSplit\__CompositeFiles, structure mirrored
bloodsplit --colourMode red 00FF88 --softAlpha 30
names and hex mix freely; soft edges
