PARTICIPANTS

Description

PARTICIPANTS is a 1-indexed array of CCK PlayerHandle objects — one per participant currently in the session. Use it for any per-participant operation: looking up positions, dispatching haptics, sending side-channel messages, reading bone transforms. The 1-indexing matches LUIDA's pID numbering everywhere else (the Web Console, the data exports, the participant manager), so PARTICIPANTS[1] is "participant 1" — not the second participant.

Parameters

Not a function. Indexed as PARTICIPANTS[n] where n is a 1-based participant index.

Side effects

• Reads only — no writes, no signals. Iterating or reading from PARTICIPANTS doesn't change experiment state.
• The array is populated by ParticipantManager once the session has started and stays stable for the duration. Early-init code (before participant manager has run) may see an empty array.
• PARTICIPANTS[0] is undefined — the 1-indexed convention bites JavaScript programmers more often than any other LUIDA quirk. Always start indexing at 1.
• Disconnects don't shift other indices: if participant 2 leaves, PARTICIPANTS[2] becomes undefined (or a stale handle that throws on use). Always guard if (PARTICIPANTS[n]) before calling methods.
• The full method set on each handle is in Assets/Doc/CCK-Types.d.ts under PlayerHandle — bone positions, send/receive, teleport, kick, etc.

Example

Dispatch a 100 ms right-controller haptic to participant 1 (the most common single-participant pattern):

const p1 = PARTICIPANTS[1];
if (p1) {
  p1.send("haptics", { target: "right", frequency: 200, amplitude: 0.7, duration: 0.1 });
}

Read participant 2's head world position in a paired study (pNum=2):

const p2 = PARTICIPANTS[2];
if (p2) {
  const headPos = p2.getHumanoidBonePosition(HumanoidBone.Head);
  // ...do something with headPos
}

When you only need to address the player from a higher-level action like SendHaptics or AssignAvatarToParticipant, you pass the participant index directly and the action resolves through PARTICIPANTS internally — you don't have to touch the array.

Related

• CONDITION — the other built-in global; together they answer "who is playing?" and "what condition is this trial?".
• SendHaptics(participantId, ...) and SendViaOsc(participantId, ...) — per-participant actions that resolve through PARTICIPANTS.
• SyncWithParticipantBone(participantIndex, ...) — uses PARTICIPANTS[participantIndex].getHumanoidBonePosition under the hood.
• Reference → Variables → PARTICIPANTS — the deeper write-up with the indexing gotchas and the caveat list.
• Concepts → Conditions, sessions, participants — how pID is assigned and how multi-participant sessions are formed.

Source

Assets/Doc/LUIDA-StateListeningItemScriptDoc.md

- An array of PlayerHandle of the participants joining this experiment."
- Use `PARTICIPANTS[1]` to retrieve the first participant, `PARTICIPANTS[2]` to retrieve the second participant, etc.