Show SFU participants who are not Matrix members

So that we can load SFU with the virtual participants and get them
displayed in the grid layout. Before that only participants who are part
of the Matrix were displayed (i.e. participants who have published
m.call.member event to declare their participation).

src/room/InCallView.tsx

@@ -34,7 +34,6 @@ import { useTranslation } from "react-i18next";
 import useMeasure from "react-use-measure";
 
 import type { IWidgetApiRequest } from "matrix-widget-api";
-import { Avatar } from "../Avatar";
 import {
   Header,
   LeftNav,
@@ -236,24 +235,6 @@ export function InCallView({
   const reducedControls = boundsValid && bounds.width <= 400;
   const noControls = reducedControls && bounds.height <= 400;
 
-  const renderAvatar = useCallback(
-    (roomMember: RoomMember, width: number, height: number) => {
-      const avatarUrl = roomMember.getMxcAvatarUrl();
-      const size = Math.round(Math.min(width, height) / 2);
-
-      return (
-        <Avatar
-          key={roomMember.userId}
-          size={size}
-          src={avatarUrl ?? undefined}
-          fallback={roomMember.name.slice(0, 1).toUpperCase()}
-          className={styles.avatar}
-        />
-      );
-    },
-    []
-  );
-
   const prefersReducedMotion = usePrefersReducedMotion();
 
   const items = useParticipantTiles(livekitRoom, participants);
@@ -273,13 +254,7 @@ export function InCallView({
         layout={layout}
         disableAnimations={prefersReducedMotion || isSafari}
       >
-        {(child) => (
-          <VideoTileContainer
-            getAvatar={renderAvatar}
-            item={child.data}
-            {...child}
-          />
-        )}
+        {(child) => <VideoTileContainer item={child.data} {...child} />}
       </VideoGrid>
     );
   };
@@ -375,17 +350,21 @@ function useParticipantTiles(
   });
 
   const items = useMemo(() => {
-    const tiles: TileDescriptor<ItemData>[] = [];
+    // The IDs of the participants who published membership event to the room (i.e. are present from Matrix perspective).
+    const matrixParticipants: Map<string, RoomMember> = new Map(
+      [...participants.entries()].flatMap(([user, devicesMap]) => {
+        return [...devicesMap.keys()].map((deviceId) => [
+          `${user.userId}:${deviceId}`,
+          user,
+        ]);
+      })
+    );
 
-    for (const [member, participantMap] of participants) {
-      for (const [deviceId] of participantMap) {
-        const id = `${member.userId}:${deviceId}`;
-        const sfuParticipant = sfuParticipants.find((p) => p.identity === id);
-
-        // Skip rendering participants that did not connect to the SFU.
-        if (!sfuParticipant) {
-          continue;
-        }
+    // Iterate over SFU participants (those who actually are present from the SFU perspective) and create tiles for them.
+    const tiles: TileDescriptor<ItemData>[] = sfuParticipants.flatMap(
+      (sfuParticipant) => {
+        const id = sfuParticipant.identity;
+        const member = matrixParticipants.get(id);
 
         const userMediaTile = {
           id,
@@ -398,12 +377,10 @@ function useParticipantTiles(
           },
         };
 
-        // Add a tile for user media.
-        tiles.push(userMediaTile);
-
         // If there is a screen sharing enabled for this participant, create a tile for it as well.
+        let screenShareTile: TileDescriptor<ItemData> | undefined;
         if (sfuParticipant.isScreenShareEnabled) {
-          const screenShareTile = {
+          screenShareTile = {
             ...userMediaTile,
             id: `${id}:screen-share`,
             focused: true,
@@ -412,10 +389,13 @@ function useParticipantTiles(
               content: TileContent.ScreenShare,
             },
           };
-          tiles.push(screenShareTile);
         }
+
+        return screenShareTile
+          ? [userMediaTile, screenShareTile]
+          : [userMediaTile];
       }
-    }
+    );
 
     PosthogAnalytics.instance.eventCallEnded.cacheParticipantCountChanged(
       tiles.length