CAMLBOY is a Game Boy emulator that runs in the browser. It is written in OCaml and compiled to JavaScript using js_of_ocaml.
Try it out in our demo page!
- English: https://linoscope.github.io/writing-a-game-boy-emulator-in-ocaml/
- 日本語: https://qiita.com/linoscope/items/244d931aaae07df2c27e
- Playable in the browser of middle-tier/high-tier mobile devices
- Readable/maintainable code that follows OCaml's best practices
- Achieve stable 60fps in low-tier mobile devices
- Serve as a benchmark target for various compile backends, similar to optcarrot in the Ruby world. Would be especially interesting if we can compare the performance of various JS/wasm backends, such as js_of_ocaml, Rescript, Melange, and ocaml-wasm.
- Run all games with high accuracy
- Optimize performance to the limit at the expense of code readability
- Runs with "playable" FPS in middle-tier mobile devices. (It runs at 60FPS for most games in my Galaxy S9, a smartphone released in 2018)
- Runs with ~1000FPS, with UI, in native
- Supports headless benchmarking mode, both for native and web, that runs without UI
- Passes various test ROMs such as Blargg's
cpu_insrts.gb
andinstr_timing.gb
(tests using Blargg's test ROMs can be found here, and tests using Mooneye's test ROMs can be found here).
We ran the first 1500 frames of Tobu Tobu Girl in headless mode (i.e., without UI) for ten times each and calculated the average FPS. The error bars represent the standard deviation. See benchmark.md
for details about the environment/commands used for the benchmark.1
Here is a rough sketch of the various modules and their relationship. You can find details in the accompanied blog post.
lib
- Main emulator codebin
- UI codeweb
- Websdl2
- SDL2
test
unit_tests
- Unit testsrom_tests
- Integration tests that use test roms
resource
games
- Game romstest_roms
- Test roms used inrom_tests
- Cartridge based save