43 lines
1.6 KiB
Markdown
43 lines
1.6 KiB
Markdown
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# Daedalian Opus — recompiled to Rust
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A proof of concept: the Game Boy game's code, statically translated from the
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disassembly into Rust, running on a tiny hand-written hardware layer.
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```
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cargo run --release
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```
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Controls: arrows = D-pad, Z = A, X = B, Enter = Start, Right Shift/Backspace = Select, Esc = quit.
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## How it works
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- `src/game.rs` is **generated** by `../recompile.py` from the traced
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disassembly: every SM83 instruction becomes Rust statements, grouped into
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basic blocks (`match m.pc { 0x0164 => { ... } }`), each commented with the
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original assembly. No SM83 code is decoded at runtime. The game's stack lives
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in emulated memory because the game manipulates return addresses itself.
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- `assets/rom_data.bin` is the ROM with every code byte zeroed — only the
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data (levels, graphics, music, text) is used. The runtime warns if the game
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ever reads a code byte as data.
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- `src/machine.rs`: registers/flags/ALU, memory map, joypad, OAM DMA, the
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vblank interrupt, and a once-per-frame LCD renderer.
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- `src/apu.rs`: the four sound channels, synthesized in step with the
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recompiled code; played through `cpal`.
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- `src/main.rs`: `winit` window + `pixels` framebuffer, 59.73 Hz pacing.
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Regenerate after changing the recompiler:
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```
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python3 ../recompile.py "../Daedalian Opus (USA).gb" src/game.rs assets/rom_data.bin
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```
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## Headless testing
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```
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cargo run -- --headless OUT_DIR 120 start:3 90 shot:title peek:C0A1:2 goto:44:54
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```
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Tokens: `N` run N frames, `BUTTON:N` hold a button N frames, `shot:NAME` save a
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PNG, `peek:ADDR:N` print memory, `goto:YY:XX` steer the puzzle cursor. All
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audio is written to `OUT_DIR/audio.wav`.
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