andy
9d82d99c15
- LHA -lh5/-lh6/-lh7 decoding with CRC checks (disk 1 is mostly lh5) - Real track palettes and set names, read from each track file's header - Camaro, plus the caravan as a towable trailer (Caravans option) - Drivers' names, menu pictures and the original .set values per car - Original sound effects (IFF 8SVX) through a new sample mixer: engine pitched with revs, tyre screech, crashes, backfire, horn, start beeps - The original tune (OctaMED MMD1) through a new player; loudness tracks OpenMPT's render through the whole song. Music option in the menu - Title picture (IFF ILBM) at the top of the menu - skids unpack and skids music commands - Gate crossings now judged on each car's whole movement per frame, including collision knocks; stalled computer cars are put back on the line after 8 seconds The executable's game logic (handling, AI) is still not decoded.
134 lines
5.6 KiB
Markdown
134 lines
5.6 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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The game's data was converted from the six original ADF disk images into
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editable files in [`assets/`](assets/README.md). The images themselves
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aren't kept in this repository.
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- **Each track:** a 16-colour PNG (the PNG's palette is the track's
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palette), plus a text file with the lap gates and height map.
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- **Each car:** a PNG sprite sheet and menu picture, plus a text file with
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its name, driver and handling.
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- **Sounds:** WAV files.
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- **Music:** the tune, as an OctaMED module.
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- **Pictures:** the title picture and a few other images, as PNGs.
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Edit them with any image editor or text editor. The build embeds the
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`assets/` folder, so the finished program is a single self-contained file.
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The engine can still read the original disks directly: ADF images, the LHA
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archives on them, and their CrunchMania-packed files.
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`skids extract --data <adfs>` regenerates `assets/` from them.
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Because the binary and `assets/` carry the original game data, anyone you
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give either to also gets the game data.
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## What works
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- All 24 tracks across the four track files, in their original palettes.
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Each has its isometric height map and lap gates.
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- All 9 cars (Mini, Beetle, Porsche, Formula 1, Midget, Truck, Police,
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Cow, Camaro) with their drivers' names, each with 32 headings and 25
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body-tilt frames for hills.
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- The caravan: turn on **Caravans** in the menu and every car tows one.
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- The original sound effects, and the original tune played by a built-in
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OctaMED player. The menu has a **Music** option: menus, always, or off.
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- The original title picture.
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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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- Engine note pitched with revs, tyre screech, crashes, backfires, a horn
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and start beeps, all from the original samples.
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## What's reconstructed
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The executable is on disk 1, but its game logic, a compiled Blitz Basic 2
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program, hasn't been decoded. So the **handling, computer drivers and race
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rules** are new code written to feel like the original, not a translation
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of it.
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Each car's original settings file has eleven handling numbers whose
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meaning lives in that code. They're kept in the car's settings asset for
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when it is decoded. [docs/FORMATS.md](docs/FORMATS.md) covers everything
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reverse engineered so 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. `DIR` can be an
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assets folder, which lets you try edits without rebuilding:
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`skids --data assets`. It can also be the original ADF images or LHA
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archives. Without `--data`, a folder like that in the current directory or
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next to the executable is picked up automatically. When a track or car
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exists both as an asset and on disk, the asset wins.
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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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| Horn | Right Shift | Left Shift |
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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 ADFS [--out assets] # convert original disks into editable assets
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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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skids music --out tune.wav --seconds 60 # render the tune to WAV
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skids unpack disk.adf --out files/ # extract a disk or LHA archive as-is
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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 `assets/`. To use a different folder, set
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`SKIDS_ASSETS_DIR=/path/to/assets`. To build without embedding, so the game
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needs `--data` at run time, use `--no-default-features --features audio`.
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The ADF images aren't needed to build.
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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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assets/ the game data as editable PNG and text files
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build.rs embeds assets/ into the executable
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src/formats/ ADF (OFS/FFS), LHA (incl. -lh5-), CrunchMania, IFF 8SVX/ILBM, OctaMED
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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 sample mixer and sound effects (cpal)
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src/music.rs OctaMED player
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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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