Declavatar 2

Declarative Avatar Asset Composing Tool; Revised

Declavatar 2 compiles a Lua script into VRChat avatar data: Expression Parameters, animator controllers for every playable layer and the Expression Menu. It is a redesign of declavatar with a Rust core, a C FFI and a byte-level interop format that any client can read.

Packages

Crate	Contents
declavatar2	The library: Lua interpreter, declaration model, transform and interop encoder.
da2	The C ABI (da2.dll, libda2.so, libda2.dylib) that wraps declavatar2::compile.

A Script

local da = require "declavatar"

local Face = da.renderer("Face")
local hat = da.symbol("ENABLE_HAT")

return da.avatar({
    parameters = {
        da.provided("VRChat"),
        da.int("Emote", { default = 0 }),
        hat and da.bool("Hat", { scope = "local" }),
    },
    controllers = {
        da.controller("fx", {
            da.group_layer("Expressions", { driven_by = "Emote" }, {
                da.default { Face:shape("eyelid_L", 0.3) },
                da.option("smile", { Face:shape("smile"), Face:shape("eye_joy", 0.5) }),
            }),
            hat and da.switch_layer("Hat", { driven_by = "Hat" }, { da.object("Hat"):active() }),
        }),
    },
    menu = {
        hat and da.toggle("Hat", da.drive_switch("Hat")),
    },
})

A script requires declavatar and returns exactly one da.avatar(...). Builders validate their arguments at the call site, and the transform reports every unresolved reference with the line of the script that wrote it. da.symbol asks whether the client supplied a symbol, so conditional content is plain Lua control flow.

Editor completion comes from the lua-language-server definitions under declavatar2/lua/types; see declavatar2/lua/README.md.

Building

Rust 1.89 or later is required.

cargo build -p da2 --release

produces the shared library under target/release. The release profile uses fat LTO, and on Windows the C runtime is linked statically, so the DLL needs no redistributable. Tagged releases on GitHub carry prebuilt binaries for Windows x86_64, Linux x86_64 and a universal macOS build together with da2.h.

cargo test runs the whole suite, including the interop round trips and the golden blobs under declavatar2/tests/golden. After changing the FFI surface, regenerate the header with cargo build -p da2 --features bindings.

Contributing

See CONTRIBUTING.md. The design decisions behind the Lua API, the transform and the interop format are recorded in AGENTS.md.

License

SPDX: Apache-2.0 OR MIT