andy
15ba71587c
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.
94 lines
3.2 KiB
Markdown
94 lines
3.2 KiB
Markdown
# Game assets
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Everything the game uses is stored here as editable files. The build embeds
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this folder into the executable. To pick up changes:
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- **Rebuild:** `cargo run --release`.
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- **Or skip the rebuild:** run with `--data assets`. Files given with
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`--data` override the built-in copy.
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These files were converted from the original Amiga disks with
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`skids extract --data <folder with the ADFs>`. That conversion is lossless,
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and running it again overwrites your edits.
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## Tracks: `tracks/<name>/`
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### `track.png`
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The track picture: 1024 × 512, a 16-colour indexed (palette) image.
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- **Palette:** the PNG's palette is the track's palette. Change a palette
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entry to recolour every pixel that uses it.
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- **Road vs scenery:** colours 8–15 are road (full grip, full speed).
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Colours 0–7 are scenery (less grip, slower).
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- **Painting a new route:** paint it with the upper eight colours and
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update the gates to match.
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- **Saving:** keep the image indexed if your editor allows it. If it saves
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as full-colour RGB instead, each pixel is matched to the nearest default
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colour, which loses your palette.
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### `track.txt`
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Plain text; lines starting with `#` are comments.
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- **`gate x1 y1 x2 y2`:** lap gates in race order.
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- Gate 0 is the start/finish line, and the grid forms up behind it.
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- Cars must cross every gate, in order, to complete a lap. Computer
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drivers steer from one gate to the next.
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- Coordinates are on the isometric ground plane. To find where a point
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sits in the picture:
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`picture x = wx - wy + 512`, `picture y = (wx + wy) × 31/64 − 252`.
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- `skids trace --data assets --track N --out t.png` draws the gates
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(gate 0 in yellow) and the computer cars' paths over the picture.
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- **`height`:** 64 rows of 64 numbers giving ground height × 256. Each
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number covers a 16 × 8 pixel cell of the picture. Slopes push cars
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downhill and tilt the car sprites.
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- **`start`, `flags`:** values from the original data that the game
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doesn't use.
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To add a track, make a new folder with both files. Tracks are listed in
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name order.
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## Vehicles: `vehicles/<id>.png` and `<id>.txt`
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### `<id>.png`
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A 2048 × 800 sprite sheet: 32 headings across by 25 tilts down, each cell
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64 × 32.
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- **Colours:** use only palette indices 0–3:
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- 0 transparent
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- 1 tyres / shadow
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- 2 trim
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- 3 bodywork
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The colours in the file are only a preview; each player's car is
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recoloured at run time.
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- **Headings:** column 12 faces right, and columns advance clockwise in
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11.25° steps.
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- **Tilts:** row = roll × 5 + pitch (each 0–4), so row 12 is the car on
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flat ground.
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### `<id>.txt`
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The display name and handling:
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| Setting | Meaning |
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|-----------|---------|
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| `top` | top speed on tarmac |
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| `accel` | acceleration |
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| `brake` | braking |
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| `grip` | sideways grip; higher means less sliding |
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| `turn` | steering rate |
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| `mass` | weight in collisions |
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| `offroad` | speed and grip multiplier on scenery |
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To add a car, add a new `<id>.png` / `<id>.txt` pair.
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## Palettes: `palettes/*.pal` (optional)
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16 lines of `RRGGBB`. Each file overrides the PNG palettes:
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- `track1-3.pal`: one track
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- `track1.pal`: every TRACK1 track
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- `default.pal`: all tracks
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