spine-rs-cli

A lightweight command-line interface tool for rendering Spine animations to PNG images using Rust and the rusty_spine library.

Overview

spine-rs-cli provides a simple workflow to load Spine skeleton data (JSON or binary) along with its associated texture atlas, compose skins, and render a specified animation frame (or looping animation) directly to a PNG image. It's ideal for automated asset generation, batch rendering, or integrating Spine rendering into Rust-based toolchains.

Architecture

• CLI Entry Point (main.rs)

  • Uses clap for argument parsing and subcommands.
  • Defines a Render subcommand for PNG generation.
  • Sets up texture callbacks and initializes miniquad window to drive the rendering loop.

• Rendering Module (spine.rs)

  • SpineInfo: Configuration struct holding paths, animation name, position, scale, skin, and culling options.
  • Spine: Handles loading the atlas, skeleton data (JSON or binary), creating the SkeletonController, and configuring animation playback.
  • Render: Implements miniquad::EventHandler to update and draw the skeleton each frame, manage GPU buffers, and handle texture loading/disposal.
  • Blend mode support, premultiplied alpha detection, backface culling, and animation event logging.

Features

• Render Spine JSON or binary skeletons.
• Composite multiple skins onto a base skin.
• Loop animations or render a single frame.
• Configurable position, scale, and backface culling.
• Automatic premultiplied alpha handling and blend mode support.
• Lightweight dependency on rusty_spine, miniquad, and glam.

Installation

Ensure you have Rust and Cargo installed. Then:

git clone https://github.com/yourusername/spine-rs-cli.git
cd spine-rs-cli
cargo build --release

The compiled binary will be available at target/release/spine-rs-cli.

Usage

Render Subcommand

Generate a PNG from a Spine JSON skeleton and atlas:

spine-rs-cli render \
  --json path/to/skeleton.json \
  --atlas path/to/skeleton.atlas \
  --out output.png \
  --base-skin "BASES/Broccoli_Base" \
  --skins "Skin1,Skin2"

• --json <FILE>: Path to the Spine skeleton JSON file.
• --atlas <FILE>: Path to the Spine atlas file (.atlas).
• --out <FILE>: Output path for the generated PNG (default: out.png).
• --base-skin <NAME>: Name of the base skin in the skeleton data.
• --skins <LIST>: Comma-separated list of additional skin names to composite.

Examples

• Basic render:

  spine-rs-cli render --json hero.json --atlas hero.atlas --out hero.png

• With custom skins:

  spine-rs-cli render \
    --json hero.json \
    --atlas hero.atlas \
    --out hero_custom.png \
    --base-skin "Hero_Base" \
    --skins "Hero_Armor,Hero_Shield"

License

MIT License. See LICENSE for details.

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Happy rendering! Feel free to open issues or contribute.