# Daedalian Opus — recompiled to Rust

A proof of concept: the Game Boy game's code, statically translated from the
disassembly into Rust, running on a tiny hand-written hardware layer.

```
cargo run --release
```

Controls: arrows = D-pad, Z = A, X = B, Enter = Start, Right Shift/Backspace = Select, Esc = quit.

## How it works

- `src/game.rs` is **generated** by `../recompile.py` from the traced
  disassembly: every SM83 instruction becomes Rust statements, grouped into
  basic blocks (`match m.pc { 0x0164 => { ... } }`), each commented with the
  original assembly. No SM83 code is decoded at runtime. The game's stack lives
  in emulated memory because the game manipulates return addresses itself.
- `assets/rom_data.bin` is the ROM with every code byte zeroed — only the
  data (levels, graphics, music, text) is used. The runtime warns if the game
  ever reads a code byte as data.
- `src/machine.rs`: registers/flags/ALU, memory map, joypad, OAM DMA, the
  vblank interrupt, and a once-per-frame LCD renderer.
- `src/apu.rs`: the four sound channels, synthesized in step with the
  recompiled code; played through `cpal`.
- `src/main.rs`: `winit` window + `pixels` framebuffer, 59.73 Hz pacing.

Regenerate after changing the recompiler:

```
python3 ../recompile.py "../Daedalian Opus (USA).gb" src/game.rs assets/rom_data.bin
```

## Headless testing

```
cargo run -- --headless OUT_DIR 120 start:3 90 shot:title peek:C0A1:2 goto:44:54
```

Tokens: `N` run N frames, `BUTTON:N` hold a button N frames, `shot:NAME` save a
PNG, `peek:ADDR:N` print memory, `goto:YY:XX` steer the puzzle cursor. All
audio is written to `OUT_DIR/audio.wav`.