# galdr

A terminal **grid synthesizer**. Signal flows downward through a field of
single-glyph unit generators; every incoming MIDI note voices the whole grid;
the mix is rendered low-latency to PipeWire. It is orca's voice — the same
esoteric, spatial approach to programming, but for making sound instead of
sending events.

```
orca-rs  ──MIDI/OSC/UDP──▶  galdr  ──PipeWire──▶  speakers
   compose the pattern       voice it       (spectrust -p visualizes it)
```

## The grid

Signal flows **down**: each cell takes the sample from the cell above as its
input. The left and right neighbour glyphs are parameters — a digit `0`–`9` is
a constant, a letter `a`–`z` reads MIDI CC (`a` = CC 0).

| glyph | unit generator |
|---|---|
| `~` | sine (ratio ← left) |
| `^` | saw (ratio ← left) |
| `_` | pulse (width ← left) |
| `v` | triangle |
| `*` | noise |
| `f` | lowpass (cutoff ← left) |
| `e` | envelope, attack/release ← left/right, gated by the note |
| `s` | shaper / drive ← left |
| `!` | output to master |

Each `!` sums into the master, so parallel columns stack timbres or voices.
A note plays every column at once.

Example — a filtered saw with an envelope:

```
^        saw at the note pitch
f        lowpass, cutoff from the digit to its left...
e        ...enveloped by the note gate
!        ...to master
```

Editing the grid recompiles and hot-swaps the running program without dropping
audio.

## Usage

```
galdr [--latency <frames>] [--poly <n>] [--rate <hz>] [--midi-name <s>]
```

galdr creates a virtual MIDI input port named **galdr**; connect orca or any
sequencer/DAW to it. `--midi-name` connects to an existing port instead.
Cursor keys move; type a glyph to place it; Backspace clears; Esc quits.

Runtime deps: PipeWire and ALSA (MIDI). Built in Rust; reuses the native
PipeWire path from spectrust.