doom-flow

Play: godofecht.github.io/doom-flow

Doom, rewritten in Flow. Native build uses Flow's C backend. The browser demo ships with the MLIR backend (MLIR to LLVM to emcc). Framebuffer output is byte-identical to the C backend, verified across 3000 frames.

Flow language	github.com/flooooooooooow/flow
Flow wiki	flooooooooooow.github.io/flow
WASM gallery	wiki /wasm/
RL sister repo	doom-flow-rl

Compile path

*.flow  ──flow.transpiler──►  C  ──clang──►  native (macOS gfx)
         │
         ├── --c ──────────►  emcc + gfx_wasm.c ──►  .wasm (Pages default)
         └── --mlir --llvm ►  emcc + gfx_wasm.c ──►  .wasm (BACKEND=mlir)

CI records the GIF with Flow’s headless gfx-record path (FLOW_GFX_RECORD_* + frames_to_gif.py), same idea as flow record.

Build and run (native)

Needs Flow at ~/flow (or sibling ../flow; see flow.toml), Python 3, clang, macOS. Shareware DOOM1.WAD is included.

~/flow/flow build-native
./build/doom
DOOMFLOW_ARGS="-timedemo demo1" ./build/doom   # must print: timed 5026 gametics

Browser / WASM

FLOW_DIR=~/flow ./scripts/build_wasm.sh                 # C backend (Pages)
FLOW_DIR=~/flow BACKEND=mlir ./scripts/build_wasm.sh    # MLIR → LLVM → emcc
python3 -m http.server 8000 --directory site

MLIR build (2026-08-10): Pages ships the MLIR backend. The game loop is rAF-driven: main() returns after init, JS calls doomflow_frame() and doomflow_present() per requestAnimationFrame. No ASYNCIFY. The C backend is still used for native macOS builds.

Pages modes: Play, Watch AI (DOOMFLOW_AI pilot), RL Arena.

Known quirks (browser path):

• IWAD is preloaded (doom.data to /doom1.wad); TITLEPIC/HUD load.
• Audio is silent. FEATURE_SOUND is off in this port.
• Light tables must use native pointer width (wasm32 is not LP64); a hardcoded * 8 row stride used to blank walls/sprites in dim areas.

Stock Flow can also build snake-class gfx + preload without this script:

~/flow/flow wasm examples/games/snake_gfx.flow --backend=mlir
~/flow/flow wasm prog.flow --backend=mlir \
  --preload DOOM1.WAD@/doom1.wad \
  --link runtime/flow_rt_support.c \
  --initial-memory=64MB

Doom uses scripts/build_wasm.sh for the extra exported AI symbols (_doomflow_set_ai, _doomflow_get_ai) and -DNORMALUNIX.

Record a GIF

FLOW_DIR=~/flow ./scripts/record_gif.sh
# optional: --frames 180 --out media/doom.gif --args "-timedemo demo1"

Controls

Arrows / WASD move · X or F fire · Space or E use · 1–7 weapons · Tab automap · Esc menu.

See PORTING.md for how the C→Flow port works.