Bad Piggies Editor

A level and save-file editor for Bad Piggies, written in Rust.

Built with egui, eframe, and wgpu. Runs as a native desktop app on macOS, Windows, and Linux, and compiles to WASM for in-browser use.

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Features

Category	Details
Level editing	Open/save .bytes, .yaml, .yml, .toml level files; visually inspect and edit objects, terrain, and overrides
Save editing	Open Progress.dat, *.contraption, Achievements.xml; edit as raw XML or structured tables; re-export as encrypted saves
Rendering	GPU-backed rendering of terrain fills, edges, sprites, opaque props, parallax backgrounds, and dark-mask overlays
CLI	Convert formats, decrypt/encrypt save files from the command line
i18n	Fluent-based UI localization with runtime locale discovery (assets/locales/*.ftl)
Targets	Native desktop (Vulkan / Metal / DX12 / OpenGL ES 3.1) + WASM/browser

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Getting Started

Prerequisites

• Rust 1.85+
• Native: a GPU that supports Vulkan, Metal, DirectX 12, or OpenGL ES 3.1
• Linux native: system libraries needed by eframe/winit (X11/Wayland headers, etc.)
• WASM: rustup target add wasm32-unknown-unknown and Trunk

Run natively

cargo run                  # debug
cargo build --release      # optimized binary

Run in the browser

rustup target add wasm32-unknown-unknown
cargo install trunk
trunk serve index.html     # opens at http://localhost:8080

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CLI Usage

The compiled binary doubles as a CLI tool. From the repo you can invoke it with cargo run -- <args>.

# Level format conversion
badpiggies-editor convert level.bytes level.yaml
badpiggies-editor convert level.yaml  level.toml
badpiggies-editor convert level.toml  level.bytes

# Save file crypto
badpiggies-editor decrypt Progress.dat -o Progress.xml
badpiggies-editor encrypt Progress.xml Progress.dat

# Help
badpiggies-editor --help
badpiggies-editor convert --help

CLI output is localized the same way as the GUI.

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Assets and Build System

How assets are resolved

Unity game assets are loaded at runtime from a Unity package file (.unitypackage):

1. Uses BP_EDITOR_EXTERNAL_UNITYPACKAGE_PATH when provided.
2. Otherwise defaults to assets/data/Bad-Piggies-2.3.6-Unity-Windows.unitypackage (relative to the process working directory).
3. Parses package entries (<guid>/asset, <guid>/asset.meta, <guid>/pathname) and serves Unity path lookups from that runtime index.

Editor runtime resources under editor/assets/ are loaded from disk at runtime on native builds. That includes icons, fonts, locales, and shaders. WASM builds also load these resources at runtime over HTTP (default base URL: assets/).

Runtime-only model (no embedded Unity assets):

• BP_EDITOR_EXTERNAL_UNITYPACKAGE_PATH=/path/to/Bad-Piggies-2.3.6-Unity-Windows.unitypackage
• BP_EDITOR_RUNTIME_ASSETS_DIR=/path/to/editor/assets for editor UI resources (icons, shaders, locales, fonts)

Custom Localization

You can add custom UI languages by dropping new Fluent files into editor/assets/locales/:

• File naming: <lang-tag>.ftl (examples: ja-JP.ftl, fr-FR.ftl, de-DE.ftl)
• Native builds auto-discover all locales/*.ftl files at startup and show them in the language menu.
• System locale matching prefers exact tag (fr-FR), then primary language (fr), then falls back to English.
• WASM currently discovers languages from preloaded runtime assets; by default this includes bundled locales.

Environment variables

Variable	Effect
BP_EDITOR_EXTERNAL_UNITYPACKAGE_PATH	Runtime external .unitypackage used directly by the editor on native builds
BP_EDITOR_RUNTIME_ASSETS_DIR	Runtime external editor/assets root for UI shaders/icons/locales/fonts

# Run with runtime unitypackage + runtime editor assets
BP_EDITOR_EXTERNAL_UNITYPACKAGE_PATH=/path/to/Bad-Piggies-2.3.6-Unity-Windows.unitypackage \
BP_EDITOR_RUNTIME_ASSETS_DIR=/path/to/badpiggies/editor/assets \
cargo run --release

# Or rely on bundled default package path under cwd
BP_EDITOR_RUNTIME_ASSETS_DIR=/path/to/badpiggies/editor/assets \
cargo run --release

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Keyboard Shortcuts

Key	Action
B	Toggle background rendering
⌘Z / Ctrl+Z	Undo
⇧⌘Z / Ctrl+Y	Redo
Scroll wheel	Zoom in / out
Drag on empty canvas	Pan
Click object	Select

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Repository Layout

badpiggies-editor/
├── assets/              # Bundled resources (icons, fonts, shaders, locales, Unity package)
├── src/
│   ├── app/             # egui shell, menus, dialogs, panels, save viewer
│   ├── data/            # Runtime asset databases and lookup tables
│   ├── diagnostics/     # Error handling and logging
│   ├── domain/          # Level types, parser/serializer, terrain generation
│   ├── i18n/            # Fluent localization files
│   ├── io/              # Save-file crypto and import/export helpers
│   ├── renderer/        # wgpu scene renderer
│   ├── unity_runtime/   # Unity runtime data adapters
│   └── main.rs          # Native + WASM entry points, CLI wiring
├── index.html           # Trunk host page for the WASM build
└── Cargo.toml

Rendering pipeline

Rendering hooks into egui via PaintCallback, sharing the same frame with the UI.

Shader	Purpose
fill_shader	Terrain fill with tiled textures
edge_shader	Terrain edges and curves
sprite_shader	Transparent sprite batching
opaque_shader	Opaque prop batching
bg_shader	Parallax background layers
dark_mask_shader	Dark overlay and lit-area masking

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Development

# Quick checks
cargo test --message-format=short
cargo check --all-targets --message-format=short
cargo clippy --all-targets --message-format=short -- -D warnings
cargo check --target wasm32-unknown-unknown --message-format=short

# Optional: parser round-trip test (requires an external fixture file)
cargo test test_level_roundtrip
# skipped automatically if the fixture is absent

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Acknowledgements

• BP-Innovation/Bad-Piggies-Original — decompiled project and asset references that made level parsing and rendering possible.

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License

Licensed under the GNU Affero General Public License v3.0. See LICENSE.

Game assets, textures, and level data are the property of Rovio Entertainment and are not covered by this license.