【m】解决远端黑屏问题

client/src/renderstreaming.js

@@ -75,10 +75,11 @@ export class RenderStreaming {
 
     if (this._isHost) {
       // host端：为该participant创建或复用peer
+      // host端始终使用polite=false（impolite），确保perfect negotiation中host的offer优先
       let peer = this._peers.get(participantId);
       if (!peer || (peer.pc && peer.pc.iceConnectionState === 'disconnected')) {
         if (peer) peer.close();
-        peer = this._preparePeerConnection(this._connectionId, offer.polite, participantId);
+        peer = this._preparePeerConnection(this._connectionId, false, participantId);
       }
       const desc = new RTCSessionDescription({ sdp: offer.sdp, type: "offer" });
       try {
@@ -87,13 +88,13 @@ export class RenderStreaming {
         Logger.warn(`Error on GotDescription for participant ${participantId}: ${error}`);
       }
     } else {
-      // participant端：使用单一peer
+      // participant端：使用单一peer，始终使用polite=true
       if (this._peer && this._peer.pc && this._peer.pc.iceConnectionState === 'disconnected') {
         this._peer.close();
         this._peer = null;
       }
       if (!this._peer) {
-        this._preparePeerConnection(offer.connectionId, offer.polite, null);
+        this._preparePeerConnection(offer.connectionId, true, null);
       }
       const desc = new RTCSessionDescription({ sdp: offer.sdp, type: "offer" });
       try {
@@ -171,10 +172,9 @@ export class RenderStreaming {
     const participantId = data.participantId;
     Logger.log(`Participant joined: ${participantId}`);
 
-    // host端：为新participant创建peer
-    if (this._isHost && !this._peers.has(participantId)) {
-      this._preparePeerConnection(this._connectionId, false, participantId);
-    }
+    // host端：不在此处创建peer，等待participant的offer到达后在_onOffer中创建
+    // 这样避免host和participant同时发offer导致的glare冲突
+    // _onOffer会在收到participant的offer时自动创建peer（如果不存在）
 
     this.onParticipantJoined(participantId);
   }