# emotes

A player emote library for Saturn Client, with limb bending.

## Layout

- `core/`: Minecraft-independent animation model (`Bone`, `BoneTransform`, `Pose`, `Animation`,
  `AnimationPlayer`). Plain Java 21 with JUnit tests. Published as `org.saturnclient:emotes-core`.
- `src/main/`: the Fabric mod that puts poses on player models. It's built once per Minecraft
  version with [Stonecutter](https://stonecutter.kikugie.dev/) and published as
  `org.saturnclient:emotes-fabric:<version>+<mc>`, with `core` bundled inside the jar.
- `src/testmod/`: a dev-only tester mod that is never published. It adds `/emotes play <name>`,
  `/emotes stop` and `/emotes info`. Press F5 to see yourself. It also has a Fabric client gametest
  that creates a world and screenshots each animation from the front and side, into
  `versions/<mc>/build/run/clientGameTest/screenshots/`.

Supported versions: 1.21.4 to 1.21.11, the same range as Saturn Client. Each version's Fabric API
version is set in `stonecutter.properties.toml`. The code uses Mojang mappings.

## How it hooks in

1. `LivingEntityRendererMixin` samples the entity's current pose into its render state (players only).
2. `HumanoidModelMixin` applies that pose at the end of `HumanoidModel.setupAnim`. `PlayerModel`
   and the armor layers both go through this method, so armor follows the pose.

Both hook points exist unchanged in every supported version. Version-specific code goes behind
Stonecutter comments, like the vertex accessors in `BentCubeRenderer`:

```java
//? if >=1.21.9 {
return new float[] { vertex.x(), vertex.y(), vertex.z(), vertex.u(), vertex.v() };
//?} else
/*return new float[] { vertex.pos().x(), vertex.pos().y(), vertex.pos().z(), vertex.u(), vertex.v() };*/
```

## Bending

Each limb bends along a single axis (`BoneTransform.bend`, `bendAxis`). It works like the cloak
renderer: build a spine, put a ring of shared vertices along it, and draw the faces between the rings.

- `LimbBend` (core) runs the spine along a cubic Bézier (`Bezier`). The control points are the rigid
  "upper half, joint, lower half" shape, and `sharpness` goes from a round curve (0) to a tight joint
  (1). The spine is cut into one ring per texture row (12 per limb), spaced evenly by arc length, so
  the limb keeps its length. Each ring moves its cross-section rigidly, so neighbouring pieces share
  vertices and the mesh stays closed.
- `QuadSplitter` (core) cuts each vanilla face into strips at the rings and splits its UVs to match.
  The texture is unchanged apart from the cuts.
- `ModelPartMixin` swaps in `BentCubeRenderer` for any part with a bend. That renderer deforms
  vanilla's own cubes, so slim arms, sleeves, pants and armor all work. Overlays and armor use the
  limb's spine, not their own inflated box, so they stay attached.

Axis 0 folds towards the front (-Z) and PI/2 towards +X, in the limb's own space. Knees fold back,
so they use axis PI. The body bends too, but the head and arms don't follow its upper half yet.
Held items still attach to the unbent arm.

## Commands

```sh
./gradlew :core:test                      # core unit tests
./gradlew :1.21.11:runTestmodClient       # launch the game with the tester (run dir: ./run)
./gradlew :1.21.11:runClientGameTest      # screenshot each test animation, then quit
./gradlew :1.21.4:compileTestmodJava      # quick compile check for one version
./gradlew buildAll                        # every version's jar → build/libs/<version>/
GITEA_TOKEN=... ./gradlew publish         # publish core + every version to Gitea
```

The active version is set in `stonecutter.gradle.kts` (`stonecutter active "..."`), and it's the
version whose code is uncommented in `src/`. Switch versions with the Stonecutter IntelliJ plugin
or the `Set active project to <v>` Gradle task. Run `Reset active project` before committing, so
the tree is committed with `vcsVersion` (1.21.11) active.

Loom 1.18 needs a Java 25 JVM to run Gradle, so the build is pinned to Loom 1.17 until the
toolchain moves. Minecraft 26.x will need that upgrade.

## Publishing

Artifacts go to the `saturnclientmc` organization's Maven registry:
`https://git.selimaj.dev/api/packages/saturnclientmc/maven`. Use a token with `package:write`, set
as `GITEA_TOKEN` or `-PgiteaToken=...`.