Backstage2D

A 2D animation and interactive-content engine in Rust. It starts from the Flash Pro model (stage, timeline, reusable animated symbols) and modernizes it:

• Compositions with named, blendable animations.
• Time instead of frames.
• A pure evaluated scene instead of a mutable display list.
• A crash-isolated stage process.
• Vector rendering with lyon on wgpu.

Status: pre-alpha. M0–M3 are done: projects play live in the editor's stage and in the standalone player; every edit is an undoable command that survives stage and editor crashes; and the editor has a real timeline, Layers, Properties, and Library, with Open/Save. M4 (on-stage editing) is next. See the roadmap, and start with docs/. The original 2012 AS3 Backstage2D is preserved on the archive branch.

Layout

Path	Purpose
crates/backstage_core	Document model (projects, compositions, animations), time, project files, evaluate, and the mixer. No GPU or GUI dependencies.
crates/backstage_render	Draws an evaluated scene with wgpu (lyon meshes, gradients, MSAA).
crates/backstage_script	Placeholder for scripting (M6).
crates/backstage_protocol	Messages and shared-memory frames between stage and tools.
crates/backstage_stage	Editing engine process: renders the stage and streams frames. (runtime side)
crates/backstage_player	Standalone player: plays a project in its own window (winit + wgpu).
crates/backstage_tools	Editor GUI (GTK 4 + Relm4). Starts and supervises the stage. (editor side)
samples/	Sample projects. bounce.bs2d is also the file-format snapshot.
scripts/check.sh	Every check CI runs: fmt, clippy, tests, and headless smoke tests.
docs/	Vision, architecture, decision records, roadmap, dev setup, and testing.

Building

See docs/dev-setup.md for the GTK 4 dev files.

export PKG_CONFIG=/home/linuxbrew/.linuxbrew/bin/pkgconf   # Homebrew GTK on Bazzite
cargo build --workspace
cargo run -p backstage_tools     # editor; starts backstage_stage itself
cargo run -p backstage_player -- samples/bounce.bs2d   # play a project in a window
cargo run -p backstage_core --example scene_dump -- samples/bounce.bs2d 0.5s   # print a scene
scripts/check.sh                 # everything CI checks (see docs/testing.md)

Editor keys: Ctrl+O / Ctrl+S / Ctrl+Shift+S open, save, and save as; Ctrl+Z / Ctrl+Shift+Z undo and redo; Enter plays or pauses the timeline; Escape clears the selection; F2 renames the selected layer. Double-click a composition in the Library (or an instance in Layers) to edit it.

Player keys: Space pauses, F / F11 toggles fullscreen, Esc or Ctrl+Q quits. --max-fps N caps the frame rate (it otherwise follows the display).

License

Copyright (c) 2026 Kevin Newman. All rights reserved. The code is public for reference only; no license is granted yet. See LICENSE.