Add basic screen sharing

src/app/voice.ts

@@ -4,11 +4,12 @@
  */
 import {
   DisconnectReason,
+  LocalParticipant,
+  LocalTrackPublication,
   Room as LiveKitRoom,
   RoomEvent,
   Track,
   type AudioCaptureOptions,
-  type LocalParticipant,
 } from "livekit-client"
 import {derived, get, writable} from "svelte/store"
 import {map, removeUndefined, uniqBy} from "@welshman/lib"
@@ -30,6 +31,7 @@ export type VoiceSession = {
   room: LiveKitRoom
   muted: boolean
   cameraOn: boolean
+  screenShareOn: boolean
 }
 
 export type Pubkey = string
@@ -220,6 +222,18 @@ const onParticipantDisconnected = (participant: {identity: string}) => {
   deleteParticipant(participant.identity)
 }
 
+const onLocalTrackUnpublished = (
+  publication: LocalTrackPublication,
+  participant: LocalParticipant,
+) => {
+  if (publication.source !== Track.Source.ScreenShare) return
+  const session = get(currentVoiceSession)
+  if (!session || participant.identity !== session.room.localParticipant.identity) return
+  if (!session.screenShareOn) return
+  currentVoiceSession.set({...session, screenShareOn: false})
+  bumpVideoCallLayoutRevision()
+}
+
 let joinAbortController: AbortController | undefined
 
 export const cancelJoinVoiceRoom = () => {
@@ -257,6 +271,7 @@ export const joinVoiceRoom = async (
     liveKitRoom.on(RoomEvent.ParticipantDisconnected, onParticipantDisconnected)
     liveKitRoom.on(RoomEvent.TrackSubscribed, onTrackSubscribed)
     liveKitRoom.on(RoomEvent.TrackUnsubscribed, onTrackUnsubscribed)
+    liveKitRoom.on(RoomEvent.LocalTrackUnpublished, onLocalTrackUnpublished)
     liveKitRoom.on(RoomEvent.ActiveSpeakersChanged, onActiveSpeakersChanged)
 
     try {
@@ -280,7 +295,14 @@ export const joinVoiceRoom = async (
 
     const muted = await setUpMicrophone(startMuted, preferredMicId, liveKitRoom.localParticipant)
 
-    currentVoiceSession.set({url, h, room: liveKitRoom, muted, cameraOn: false})
+    currentVoiceSession.set({
+      url,
+      h,
+      room: liveKitRoom,
+      muted,
+      cameraOn: false,
+      screenShareOn: false,
+    })
     voiceState.set(VoiceState.Connected)
     playJoinSound()
   } catch (e) {
@@ -307,6 +329,14 @@ export const leaveVoiceRoom = async () => {
     }
   }
 
+  if (session.screenShareOn) {
+    try {
+      await session.room.localParticipant.setScreenShareEnabled(false)
+    } catch {
+      /* pass */
+    }
+  }
+
   voiceState.set(VoiceState.Disconnected)
   videoCallLayoutRevision.set(0)
   currentVoiceSession.set(undefined)
@@ -341,26 +371,29 @@ export const toggleMute = async () => {
   }
 }
 
-const roomHasSubscribedRemoteCamera = (room: LiveKitRoom): boolean => {
+const VISUAL_SOURCES = [Track.Source.Camera, Track.Source.ScreenShare] as const
+
+const roomHasSubscribedRemoteVisual = (room: LiveKitRoom): boolean => {
   for (const p of room.remoteParticipants.values()) {
-    const pub = p.getTrackPublication(Track.Source.Camera)
-    if (pub?.isSubscribed && pub.track) return true
+    for (const source of VISUAL_SOURCES) {
+      const pub = p.getTrackPublication(source)
+      if (pub?.isSubscribed && pub.track) return true
+    }
   }
   return false
 }
 
-/** True when the connected session has local camera on or any subscribed remote camera track. */
+/** True when local camera/screen share is on or any subscribed remote camera/screen track. */
 export const videoCallContentActive = derived(
   [currentVoiceSession, voiceState, videoCallLayoutRevision],
   ([$session, $state, _rev]) => {
     if ($state !== VoiceState.Connected || !$session) return false
-    if ($session.cameraOn) return true
-    return roomHasSubscribedRemoteCamera($session.room)
+    if ($session.cameraOn || $session.screenShareOn) return true
+    return roomHasSubscribedRemoteVisual($session.room)
   },
 )
 
-/** Live camera tracks (local + remote) for layout automation. */
-const countLiveCameraFeeds = (session: VoiceSession): number => {
+const countLiveVisualFeeds = (session: VoiceSession): number => {
   const room = session.room
   let n = 0
   const lp = room.localParticipant
@@ -368,9 +401,15 @@ const countLiveCameraFeeds = (session: VoiceSession): number => {
     const pub = lp.getTrackPublication(Track.Source.Camera)
     if (pub?.track) n += 1
   }
+  if (session.screenShareOn) {
+    const pub = lp.getTrackPublication(Track.Source.ScreenShare)
+    if (pub?.track) n += 1
+  }
   for (const rp of room.remoteParticipants.values()) {
-    const pub = rp.getTrackPublication(Track.Source.Camera)
-    if (pub?.isSubscribed && pub.track) n += 1
+    for (const source of VISUAL_SOURCES) {
+      const pub = rp.getTrackPublication(source)
+      if (pub?.isSubscribed && pub.track) n += 1
+    }
   }
   return n
 }
@@ -379,7 +418,7 @@ export const videoTileCount = derived(
   [currentVoiceSession, voiceState, videoCallLayoutRevision],
   ([$session, $state, _rev]) => {
     if ($state !== VoiceState.Connected || !$session) return 0
-    return countLiveCameraFeeds($session)
+    return countLiveVisualFeeds($session)
   },
 )
 
@@ -403,3 +442,24 @@ export const toggleCamera = async () => {
     pushToast({theme: "error", message: "Could not access camera"})
   }
 }
+
+export const toggleScreenShare = async () => {
+  const session = get(currentVoiceSession)
+  if (!session) return
+
+  const screenShareOn = !session.screenShareOn
+  if (!screenShareOn) {
+    session.room.localParticipant.setScreenShareEnabled(false)
+    currentVoiceSession.set({...session, screenShareOn})
+    bumpVideoCallLayoutRevision()
+    return
+  }
+
+  try {
+    await session.room.localParticipant.setScreenShareEnabled(true)
+    currentVoiceSession.set({...session, screenShareOn})
+    bumpVideoCallLayoutRevision()
+  } catch (e) {
+    pushToast({theme: "error", message: "Could not start screen sharing"})
+  }
+}