Files

T

andy 15ba71587c Convert the game data into editable assets

assets/ now holds every track as a 16-colour indexed PNG (its palette is
the track palette) plus a text file of lap gates and height map, and
every vehicle as a PNG sprite sheet plus a text file with its name and
handling (moved out of the code). The build embeds assets/ instead of
unpacking the ADFs, so the disks are no longer needed to build either.

skids extract converts original disks to assets and checks each file
reads back identically; benchmark results from the assets match the
disks exactly. Assets win over disk data with the same name, and
--data assets picks up edits without a rebuild. assets/README.md
describes how to edit everything.

2026-10-19 19:38:08 +00:00

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Game assets

Everything the game uses is stored here as editable files. The build embeds this folder into the executable. To pick up changes:

Rebuild: cargo run --release.
Or skip the rebuild: run with --data assets. Files given with --data override the built-in copy.

These files were converted from the original Amiga disks with skids extract --data <folder with the ADFs>. That conversion is lossless, and running it again overwrites your edits.

Tracks: `tracks/<name>/`

`track.png`

The track picture: 1024 × 512, a 16-colour indexed (palette) image.

Palette: the PNG's palette is the track's palette. Change a palette entry to recolour every pixel that uses it.
Road vs scenery: colours 8–15 are road (full grip, full speed). Colours 0–7 are scenery (less grip, slower).
Painting a new route: paint it with the upper eight colours and update the gates to match.
Saving: keep the image indexed if your editor allows it. If it saves as full-colour RGB instead, each pixel is matched to the nearest default colour, which loses your palette.

`track.txt`

Plain text; lines starting with # are comments.

gate x1 y1 x2 y2: lap gates in race order.
- Gate 0 is the start/finish line, and the grid forms up behind it.
- Cars must cross every gate, in order, to complete a lap. Computer drivers steer from one gate to the next.
- Coordinates are on the isometric ground plane. To find where a point sits in the picture: picture x = wx - wy + 512, picture y = (wx + wy) × 31/64 − 252.
- skids trace --data assets --track N --out t.png draws the gates (gate 0 in yellow) and the computer cars' paths over the picture.
height: 64 rows of 64 numbers giving ground height × 256. Each number covers a 16 × 8 pixel cell of the picture. Slopes push cars downhill and tilt the car sprites.
start, flags: values from the original data that the game doesn't use.

To add a track, make a new folder with both files. Tracks are listed in name order.

Vehicles: `vehicles/<id>.png` and `<id>.txt`

`<id>.png`

A 2048 × 800 sprite sheet: 32 headings across by 25 tilts down, each cell 64 × 32.

Colours: use only palette indices 0–3:
- 0 transparent
- 1 tyres / shadow
- 2 trim
- 3 bodywork
The colours in the file are only a preview; each player's car is recoloured at run time.
Headings: column 12 faces right, and columns advance clockwise in 11.25° steps.
Tilts: row = roll × 5 + pitch (each 0–4), so row 12 is the car on flat ground.

`<id>.txt`

The display name and handling:

Setting	Meaning
`top`	top speed on tarmac
`accel`	acceleration
`brake`	braking
`grip`	sideways grip; higher means less sliding
`turn`	steering rate
`mass`	weight in collisions
`offroad`	speed and grip multiplier on scenery

To add a car, add a new <id>.png / <id>.txt pair.

Palettes: `palettes/*.pal` (optional)

16 lines of RRGGBB. Each file overrides the PNG palettes:

track1-3.pal: one track
track1.pal: every TRACK1 track
default.pal: all tracks

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Game assets

Tracks: tracks/<name>/

track.png

track.txt

Vehicles: vehicles/<id>.png and <id>.txt

<id>.png

<id>.txt

Palettes: palettes/*.pal (optional)