plusrenderer

A universal renderer for Minecraft players, cosmetics and emotes.

The Rust core reads Bedrock .geo.json and .animation.json files, evaluates MoLang and attaches cosmetics the same way the in-game client (PolyPlus) does. It then produces vertex buffers sorted back to front, which a host draws one texture run at a time.

Every host shares that core. The web build draws with WebGL2. JVM hosts load the native library (crates/ffi) through JNI (java/) or its C ABI (JNA). Rust hosts can draw with Skia (crates/skia).

Running the demo

pnpm install
pnpm dev

The demo opens at http://localhost:5173. Drag to orbit the player. Drop a cosmetic bundle (a .zip, or a .geo.json with its .png), an emote, a cape or a skin anywhere on the page to load it.

Command	What it does
pnpm dev	Builds the wasm, then starts the demo dev server
pnpm build	Writes a production bundle to packages/demo/dist
pnpm preview	Serves that bundle
pnpm wasm	Rebuilds only the wasm
pnpm test	Runs the Rust test suite

The wasm build pins cargo +1.97 because the nightly rust-lld can't link wasm here.

To build the native library, run scripts/build-native.sh <resources-dir> [rust-target...].

Using it

Releases are cut from tags. Pushing one runs .github/workflows/release.yml:

git tag v0.2.0 && git push --tags

The workflow needs the repository variable REPOSILITE_URL and the secrets REPOSILITE_USERNAME and REPOSILITE_TOKEN.

Java 8+

The jar in java/ uses JNI and ships the native library for every platform.

repositories { maven("<REPOSILITE_URL>") }
dependencies { implementation("org.polyfrost:plusrenderer:0.2.0") }

try (Renderer r = new Renderer()) {
    r.loadPlayer(0, false);
    r.pose(0);
    r.buildMesh(Renderer.JAVA_MODEL_SPACE);
}

To build and test it locally, run scripts/build-native.sh target/java-resources, then ./gradlew test in java/. Gradle itself needs JDK 17 or newer, but it compiles and tests on a Java 8 toolchain.

Rust

The launcher depends on the git tag directly. Cargo finds each crate inside the workspace.

plusrenderer = { git = "https://github.com/<owner>/<repo>", tag = "v0.2.0" }
# Optional, for drawing with Skia or Freya.
plusrenderer-skia = { git = "https://github.com/<owner>/<repo>", tag = "v0.2.0" }

If the repository is private, set net.git-fetch-with-cli = true in the launcher's .cargo/config.toml so Cargo uses your git credentials.

JavaScript

@plusrenderer/renderer combines WebGL2 and wasm. Every release attaches it as plusrenderer-renderer-<version>.tgz.

pnpm add https://github.com/<owner>/<repo>/releases/download/v0.2.0/plusrenderer-renderer-0.2.0.tgz

import { Renderer } from "@plusrenderer/renderer";

// Fetches plusrenderer.wasm from next to index.js.
const renderer = await Renderer.create(canvas);

Layout

Path	Package	Contents
crates/core	plusrenderer	Parsing, MoLang, animation, posing and vertex buffers
crates/ffi	plusrenderer-ffi	C ABI over the core for wasm and native hosts, plus JNI for java/
crates/skia	plusrenderer-skia	Skia backend on Freya's freya-skia-safe, plus a Freya viewer
packages/renderer	@plusrenderer/renderer	WebGL2 adapter
packages/demo	@plusrenderer/demo	Test page
java	org.polyfrost:plusrenderer	Java 8 JNI binding

Examples

Render the core straight to SVG:

cargo run -p plusrenderer --example dump_svg > out.svg

Draw the player in a Freya window:

cargo run -p plusrenderer-skia --example freya_viewer

The viewer calls plusrenderer_skia::draw from a rect's RenderCallback background, and Freya picks Metal, Vulkan or GL. Drag to orbit, scroll to zoom and press space to play the emote.

freya-skia-safe must stay on the version Freya uses (0.104 for freya 0.5.0-rc.10), so that both link the same Skia.

Debug skin

packages/demo/public/skin.png is a 64x64 skin where colour marks direction. Red is the model's right, which is the viewer's left when facing it. Blue is its left, green is up and yellow is down. Quadrant markers on the head's top and bottom and on the right sole show any flipped face.