A³ Motion Development

A³ Motion Controller UI

A JUCE / C++17 app drawing the sphere in OpenGL: a3-motion-ui, the ui submodule of a3-motion. It records motion from the touchscreen, stores it as ticks, plays it back on the beat clock, and speaks OSC to A³ Core. Build and test (./build.sh, ./test.sh, JUCE version): Building and testing. Hardware: A³ Motion hardware.

Current Version — V03

The A³ Motion UI, ACTION page open

The software mixer

A channel strip like the desk’s plus a summing and filter page, sending exactly the desk’s addresses, so Core can’t tell them apart.

The MIX page

  • It listens too. Core relays REAPER’s reports; the pages adopt them via MixerState::setChannelFromPeer, which sets without sending — sending would rebuild the echo loop out of Core’s reach.

  • Three handlers, onMixerChannelValue, onMasterValue, onFilterValue, each indexing its table in OscAddresses. Master and filter tables are walked after the channel ones: /master/volume and /channel/1/volume differ by one word.

  • /filter/mode arrives as a number (1 = high pass); the desk’s word goes on /filter/led.

Rest positions

A double tap rests a control only where a rest means something. On the strip, only SEND:

constexpr std::optional<float>
mixerControlRestPosition (MixerControl control)
{
  if (control == MixerControl::AuxSend)
    return 0.f;
  return {};
}

A gain snapping to a default mid-set would make a channel jump. The same table sets the start values; gain and volume start at zero with no rest. The channel-value strip (channelValueRestPosition): 3d and freq at twelve o’clock, Q shut (a filter still resonating hasn’t been reset).

Hearing where the sound is

One handler, onChannelValue, accepts five per-channel values from Core: azimuth, elevation, pot 1, pot 2, 3D. That makes total recall work: at start the device sends /state/recall, holds its output and adopts the answer (/state/recall). Output ramps count as primed only after a tick that actually sent, so a 0.0 start still reaches Core.

The status bar and the signal dots

No VU meters in the status bar: outputs are on the master column, inputs are a dot on each channel’s face.

struct VuDot
{
  bool visible = false;      // false below the meter's floor: silence is nothing
  std::size_t band = vuGreenBand;
  float alpha = 0.f;         // follows the level; the size stays put
};

  • A warning light, not a meter: a dot has no length to show how far over.

  • Silence is no dot, not a dim one.

  • RMS, not peak, or it would flicker on every hit.

  • Colour from vuBandColour, the meter’s own rule; a test pins the yellow threshold to the meter’s.

  • Repaint compares the drawn dot, not the level, which wobbles every frame.

Older Versions

The sphere before the touch rework, and before that:

Before

Panel firmware

A microcontroller (hardware) handles buttons, encoders, pots and LEDs and talks to the UI by a binary poll-frame protocol on USB serial. PlatformIO project: firmware/; build, test, flash: Building and testing.