118 lines
4.7 KiB
Markdown
118 lines
4.7 KiB
Markdown
# Skids: a Super Skidmarks revival
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A cross-platform (Windows, macOS, Linux) engine written in Rust that plays
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*Super Skidmarks* (Acid Software, 1995) on the original Amiga data.
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At build time it reads the game's ADF disk images from this repository:
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it unpacks the LHA archives on them and builds the game files into the
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executable. At run time it decrunches the CrunchMania-packed files and
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decodes the planar track graphics and AGA sprite banks. The finished
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program is a single self-contained file, with no disks needed to play.
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Because the binary carries the original game data, anyone you give a build
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to also gets the game data.
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## What works
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- All 24 tracks across the four track files. Each has its isometric height
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map and lap gates.
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- All 8 vehicles (Mini, Beetle, Porsche, Formula 1, Midget, Truck, Police,
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Cow), with 32 headings and 25 body-tilt frames for hills.
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- 1 or 2 players (split screen) plus up to 7 computer drivers.
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- Power-slide handling, slopes, car-to-car bumping, and skid marks burnt
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into the track.
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- Lap and position tracking, lap times, and a results table.
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- Procedural engine, tyre and crash sound.
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## What's reconstructed
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Disk 1 of the six-disk set is missing from this archive. It held the
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executable, palettes, sound and music. As a result:
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- **Handling, AI and race rules** are new code written to feel like the
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original, not a translation of the original 68000 code.
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- **Colours** come from a reconstructed palette, built around how the
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tracks use their 16 colour indices. If you have the real palettes, put
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them in a `palettes/` folder next to the disks as `.pal` files (16 lines
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of `RRGGBB`):
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- `track1-3.pal` for one track
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- `track1.pal` for all six tracks in a file
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- `default.pal` for everything
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- **Sound** is synthesised.
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If you find disk 1, drop it in with the others. Anything it contains under
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`track/` or `vehicles/` is picked up automatically. The format notes in
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[docs/FORMATS.md](docs/FORMATS.md) cover everything reverse engineered so
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far.
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## Running
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```sh
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cargo run --release
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```
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The built executable (`target/release/skids`, or `skids.exe` on Windows)
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runs on its own from anywhere.
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`--data DIR` adds to or overrides the built-in data with more ADF images,
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LHA archives, or extracted `track/`, `vehicles/` and `palettes/` folders.
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Without `--data`, a folder like that in the current directory or next to
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the executable is picked up automatically. That means dropping disk 1 or
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real palette files next to the game just works.
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| Action | Player 1 | Player 2 |
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|-------------|---------------------------------------|----------|
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| Accelerate | ↑ (or W in one-player games) | W |
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| Brake / reverse | ↓ (or S) | S |
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| Steer | ← → (or A D) | A D |
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| Pause | P | |
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| Leave race | Esc | |
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Options: `--scale 1|2|4` (window size), `--mute`.
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### Tools
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```sh
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skids info --data DIR # list tracks and vehicles found
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skids extract --data DIR --out pngs/ # dump every track (with gates) and car sheet
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skids bench --data DIR --seconds 120 # race CPU cars on every track: laps and time on road
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skids trace --data DIR --track 11 --out t.png # plot CPU racing lines
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skids render --data DIR --track 3 --out shot.png # headless screenshot
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```
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## Building
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You need a stable Rust toolchain.
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- **Linux:** install the ALSA and X11 development packages, e.g.
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`sudo apt install libasound2-dev libx11-dev libxkbcommon-dev`. To build
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without sound (no ALSA needed), use
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`cargo build --release --no-default-features --features embed`.
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- **macOS / Windows:** `cargo build --release` works as is.
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The build embeds the data from the `*.adf` files next to `Cargo.toml`. To
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use images from somewhere else, set `SKIDS_EMBED_DIR=/path/to/adfs`. To
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build without embedding, so the game needs `--data` at run time, use
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`--no-default-features --features audio`.
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GitHub Actions builds all three platforms on every push
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(`.github/workflows/build.yml`).
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## Layout
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```
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build.rs unpacks the ADFs and embeds the game files at build time
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src/formats/ ADF (OFS/FFS), LHA and CrunchMania readers
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src/data/ track, vehicle and palette decoding; locating the game files
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src/game/ physics, AI and race rules
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src/render/ software renderer at 320×256 (PAL low-res) and a bitmap font
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src/audio.rs synthesised sound (cpal)
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src/app.rs menus, race screens and results
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```
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## Credits
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*Super Skidmarks* is by Acid Software. This project is an unofficial
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revival for preservation. The CrunchMania bitstream layout follows Teemu
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Suutari's [ancient](https://github.com/temisu/ancient) (BSD-2-Clause).
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