Rocqman

Rocqman is a Pacman-like game written in Rocq and extracted to C++ with Crane. The game uses SDL2 for rendering, SDL2_image for loading the Rocq logo sprite, and small external audio players for sound playback. This establishes, at least informally, that Rocq is Pacman-complete.

Features

• game logic written in Rocq
• extraction to C++ with Crane
• SDL2 rendering
• smooth sprite interpolation
• sound effects for dots, power pellets, ghost kills, losing a life, game over, and victory

Requirements

You need:

• Rocq with dune
• a C++23 compiler
• pkg-config
• SDL2
• SDL2_image

Runtime audio also needs a platform player in PATH:

• macOS: afplay
• Linux: one of mpg123, ffplay, or play

Getting started

Clone the repo with everything it needs:

git clone --recurse-submodules https://github.com/joom/rocqman.git
cd rocqman

If you already cloned it without submodules, run:

git submodule update --init --recursive

Installing dependencies

macOS

Install the SDL packages with Homebrew:

brew install sdl2 sdl2_image

If you want to use Homebrew LLVM instead of the system toolchain:

brew install llvm

Linux

The exact package names vary by distribution, but you generally need:

sudo apt install clang pkg-config libsdl2-dev libsdl2-image-dev

For sound playback, also install at least one of:

sudo apt install mpg123

or

sudo apt install ffmpeg

or

sudo apt install sox

Building

Build the game:

make

This does three things:

1. uses the local Crane checkout in ./crane
2. extracts theories/Rocqman.v and theories/SDL.v to C++
3. copies the generated C++ into src/generated/
4. compiles the final executable ./rocqman

Build with a different optimization level:

make OPT=-O2

Running

Run the game:

make run

or:

./rocqman

Controls:

• arrow keys or WASD: move
• Space: pause or unpause
• Q or Esc: quit

Cleaning

Remove build outputs:

make clean

This removes:

• ./rocqman
• ./src/generated/
• ./rocqman.dSYM
• Dune build outputs

Repository structure

.
├── assets/
│   ├── *.mp3           sound effects
│   └── rocq.svg        player sprite
├── crane/              Crane submodule used for extraction
├── src/
│   └── sdl_helpers.h   C++ SDL and audio helper functions
├── theories/
│   ├── Rocqman.v       game logic, rendering, extracted main
│   ├── RocqmanProofs.v proofs about gameplay transitions and control flow
│   ├── SDL.v           Rocq-side SDL bindings and extraction directives
│   └── dune            Rocq theory stanza
├── Makefile            extraction and native build entrypoint
├── dune-project        Dune project file
└── README.md

Generated files are written to:

src/generated/

These are build artifacts and should not be edited manually.

What Is Proved

The file theories/RocqmanProofs.v contains machine-checked proofs about the current game logic. At the moment, those proofs show that the pure gameplay transitions used by the frame loop preserve key monotonicity properties: score never decreases, lives never increase, and the number of collectibles left never increases. It also proves that terminal logical states are fixed points of tick, that paused gameplay stays paused until space is pressed, that pressing space while paused returns to Playing, and that WinScreen and GameOverScreen eventually request quit once enough time has elapsed.

Development notes

• The authoritative game logic lives in Rocq, not in the generated C++.
• The build expects Crane at crane/.
• src/sdl_helpers.h is the main handwritten C++ integration layer.
• The extracted program defines its own main, so there is no separate handwritten main.cpp.
• If extraction succeeds but sound does not play on Linux, check that one of mpg123, ffplay, or play is installed.