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DynOSTiC
Jan 23, 2026

After working on Kaíven and ëëntïï, I realized I needed an engine. What I was
doing with those two projects wasn’t good enough, something was missing.
After a few back-and-forths, I remembered an idea from another story:
DYNamics Of the Space TIme Continuum. Reusing the name just felt right. In that
story, the machine lets you travel through time and space, and it can even
hange your DNA. I could keep going, but that’s probably for another time.
Anyway, I present DYNOSTIC.
Using Dynostic: A Practical Guide to the Deterministic Tactical-Sim Core
Dynostic is a reusable deterministic tactical-sim core in Rust with a LÖVE
(LuaJIT) front-end. The design goal is fast iteration on UI/feel in LÖVE while
keeping the simulation pure, deterministic, and event-sourced in Rust. This
post focuses on how to get it running and how to use the CLI and packaging
pipeline day to day.
What you are running

rust/ contains the Cargo workspace for the sim core, FFI boundary, and
CLI.
love/ is the LÖVE project that loads the Rust library and renders the UI.
Data is pack-driven, so you can create and ship content without changing
engine code.

Prerequisites

Rust toolchain (stable) with Cargo
LÖVE (LuaJIT build)
make for the convenience targets (optional)
ffmpeg only if you want offline video encoding

Quick start: build and run
From the repo root:
make build-native
This builds the dynostic_ffi dynamic library and copies it into:
love/native/<platform>/
Then run the LÖVE project:
love love
You should see a small window with a moving dot driven by the Rust sim. If the
native library is missing or mismatched, the LÖVE app will fail to load the FFI.
Create a new game scaffold
Generate a pack skeleton with the CLI:
cargo run -p dynostic_cli --manifest-path rust/Cargo.toml -- new "My Game" \
  --out games
Explore the reference game for data layout and conventions:
examples/reference_game
Packs are data-driven, so you can iterate on JSON content without touching the
engine. This is the fastest path to new units, abilities, and scenarios.
Profile the simulation
The CLI can run headless and dump hot-path counters:
cargo run -p dynostic_cli --manifest-path rust/Cargo.toml -- --ticks 200 \
  --profile
Use this when tuning pathfinding, line-of-sight, or ability targeting rules.
Work with mods (experimental)
Mods live under mods/ and are enabled via mods/mods.json. Use the CLI to add
and toggle them:
cargo run -p dynostic_cli --manifest-path rust/Cargo.toml -- mod add \
  --id cool_mod --path mods/cool_mod/pack.json --enable
cargo run -p dynostic_cli --manifest-path rust/Cargo.toml -- mod list
cargo run -p dynostic_cli --manifest-path rust/Cargo.toml \
  -- mod disable cool_mod
When a mod is enabled, its pack is merged after the base pack. Script
permissions are gated by pack.permissions.scripts (default false).
Speed up loads with pack cache
Compile pack data into a deterministic cache blob:
cargo run -p dynostic_cli --manifest-path rust/Cargo.toml -- pack cache \
  --pack love/content/pack.json
The runtime uses pack.cache.json automatically when present. Disable with
DYNOSTIC_PACK_CACHE=0 if you need to test cold loads.
Cutscenes and previews
Validate and run a deterministic cutscene timeline:
cargo run -p dynostic_cli --manifest-path rust/Cargo.toml -- cine validate \
  --timeline tools/cutscene_demo.json
cargo run -p dynostic_cli --manifest-path rust/Cargo.toml -- cine run \
  --timeline tools/cutscene_demo.json
For the LÖVE preview tool, launch the app and press F7. Use DYNOSTIC_CINE
to load a different timeline.
Package and ship
Build a portable .love archive and a platform folder with native libs:
make package-love
make package
For reproducible builds, set SOURCE_DATE_EPOCH:
SOURCE_DATE_EPOCH=1700000000 make package
To build a release manifest and verify it:
make release
make release-verify
Dynostic can sign packs and release manifests with an ed25519 key:
cargo run -p dynostic_cli --manifest-path rust/Cargo.toml -- pack keygen \
  --out-public keys/pack.pub --out-secret keys/pack.secret
cargo run -p dynostic_cli --manifest-path rust/Cargo.toml -- pack sign \
  --pack dist/pack/pack.json --key keys/pack.secret
cargo run -p dynostic_cli --manifest-path rust/Cargo.toml -- release sign \
  --manifest dist/release_manifest.json --key keys/pack.secret
Note: dynamic libraries cannot be loaded from inside a zipped .love archive.
Ship platform builds with the native library next to the executable/app bundle.
Optional: offline replay rendering
To render deterministic replays into PNG frames (or video with ffmpeg):
DYNOSTIC_RENDER=1 DYNOSTIC_RENDER_REPLAY=../tools/golden/replay_combat.json \
  make run
DYNOSTIC_RENDER=1 DYNOSTIC_RENDER_REPLAY=../tools/golden/replay_combat.json \
  DYNOSTIC_RENDER_FFMPEG=ffmpeg make run
This is useful for capture pipelines, trailers, and visual regression testing.