juballer

Rust · wgpu + egui · MIT Source: github.com/jacob-sabella/juballer

Utility platform for the GAMO2 FB9 — a USB 4×4 grid controller. Treats the device as a programmable display + input surface: each of the 16 cells is its own GPU-rendered tile, the row above the grid is a free-form HUD, and physical key presses route to whichever widget owns that cell.

Built on wgpu and egui so every cell can host a shader, an image, an animated widget, or a custom UI panel — without giving up a sub-frame input path.

Linux is the daily-driver target. Windows builds on every CI run (fmt + clippy + cargo build) but has not been exercised against real hardware.

Deck runtime

16 GPU tiles + 1 free-form top region. Each cell gets its own viewport, scissor, and pipeline state
Per-cell WGSL fragment shaders with a shared uniform block — animated backgrounds, audio-reactive scopes, status indicators
Geometry calibration overlay nudges edge padding and per-axis gaps, writes back to the active profile
Per-profile [keymap] table maps (row, col) → KEY_* so the same composition works across keyboards or controllers
Live config watcher: edit deck.toml, save, deck rebuilds widgets without restarting (debounced notify)
Built-in widgets: clock, now-playing, image tile, shader tile

Plugin host

Out-of-process plugins over a length-prefixed JSON protocol on a Unix socket — a plugin crash stops painting one tile, not the deck
Typed wire schema in juballer-deck-protocol (cell rects, paint commands, input events, lifecycle messages) — any language that can speak length-prefixed JSON can write a plugin
Action registry exposes play, calibrate, settings, mods, rhythm-launch, etc. so a tile press can switch modes

Live editor

juballer-deck editor brings up an axum HTTP + WebSocket server; REST surface for pages / widgets, WS bus for live updates
Profile reloads, page writes, preview activations all flow through one event stream
Atomic page writes: temp file + rename, no half-written deck.toml

Rhythm-game mode

The grid is the right shape for a 4×4 tap rhythm game, so the deck ships one as an optional surface. Nothing else in the workspace depends on it.

Loads charts in memon v1.0.0 — open-source JSON chart format. Tap notes, long (held) notes, mid-song BPM changes, fractional t times, per-chart timing overrides
Real-time judging with configurable hit windows, per-grade SFX, life bar, post-session offset suggestion
Chart picker: paginated grid over a *.memon directory with audio preview, jacket art, banner art, favorites, per-chart audio-offset overrides
calibrate-audio utility for dialing in audio offset
First-run tutorial mode
In-app rhythm settings + mods editors write back to deck.toml

Workspace layout

crate	role
`juballer-core`	wgpu render loop, geometry calibration, raw input, profile loader
`juballer-egui`	shared egui overlay scaffolding for HUDs, picker, editor preview
`juballer-deck`	deck runtime, widget registry, plugin host, editor server, rhythm
`juballer-deck-protocol`	typed message schema for the plugin socket
`juballer-gestures`	corner-hold / multi-press gesture recognizer for shortcuts + exits