Use 2 different ENet channels for reliable/unreliable packets

This avoids stalling other sequenced but unreliable packets
(i.e. UNRELIABLE_ORDERED) when sending RELIABLE packets.

modules/enet/networked_multiplayer_enet.cpp

@@ -32,7 +32,7 @@ Error NetworkedMultiplayerENet::create_server(int p_port, int p_max_clients, int
 
 	host = enet_host_create (& address /* the address to bind the server host to */,
 				     p_max_clients      /* allow up to 32 clients and/or outgoing connections */,
-				     2      /* allow up to 2 channels to be used, 0 and 1 */,
+				     SYSCH_MAX      /* allow up to SYSCH_MAX channels to be used */,
 				     p_in_bandwidth      /* assume any amount of incoming bandwidth */,
 				     p_out_bandwidth      /* assume any amount of outgoing bandwidth */);
 
@@ -52,7 +52,7 @@ Error NetworkedMultiplayerENet::create_client(const IP_Address& p_ip, int p_port
 
 	host = enet_host_create (NULL /* create a client host */,
 		    1 /* only allow 1 outgoing connection */,
-		    2 /* allow up 2 channels to be used, 0 and 1 */,
+		    SYSCH_MAX /* allow up to SYSCH_MAX channels to be used */,
 		    p_in_bandwidth /* 56K modem with 56 Kbps downstream bandwidth */,
 		    p_out_bandwidth /* 56K modem with 14 Kbps upstream bandwidth */);
 
@@ -70,8 +70,8 @@ Error NetworkedMultiplayerENet::create_client(const IP_Address& p_ip, int p_port
 
 	unique_id=_gen_unique_id();
 
-	/* Initiate the connection, allocating the two channels 0 and 1. */
-	ENetPeer *peer = enet_host_connect (host, & address, 2, unique_id);
+	/* Initiate the connection, allocating the enough channels */
+	ENetPeer *peer = enet_host_connect (host, & address, SYSCH_MAX, unique_id);
 
 	if (peer == NULL) {
 		enet_host_destroy(host);
@@ -148,12 +148,12 @@ void NetworkedMultiplayerENet::poll(){
 						ENetPacket * packet = enet_packet_create (NULL,8,ENET_PACKET_FLAG_RELIABLE);
 						encode_uint32(SYSMSG_ADD_PEER,&packet->data[0]);
 						encode_uint32(E->key(),&packet->data[4]);
-						enet_peer_send(event.peer,1,packet);
+						enet_peer_send(event.peer,SYSCH_CONFIG,packet);
 						//send the new peer to existing peers
 						packet = enet_packet_create (NULL,8,ENET_PACKET_FLAG_RELIABLE);
 						encode_uint32(SYSMSG_ADD_PEER,&packet->data[0]);
 						encode_uint32(*new_id,&packet->data[4]);
-						enet_peer_send(E->get(),1,packet);
+						enet_peer_send(E->get(),SYSCH_CONFIG,packet);
 					}
 				} else {
 
@@ -185,7 +185,7 @@ void NetworkedMultiplayerENet::poll(){
 							ENetPacket* packet = enet_packet_create (NULL,8,ENET_PACKET_FLAG_RELIABLE);
 							encode_uint32(SYSMSG_REMOVE_PEER,&packet->data[0]);
 							encode_uint32(*id,&packet->data[4]);
-							enet_peer_send(E->get(),1,packet);
+							enet_peer_send(E->get(),SYSCH_CONFIG,packet);
 						}
 					} else if (!server) {
 						emit_signal("server_disconnected");
@@ -204,7 +204,7 @@ void NetworkedMultiplayerENet::poll(){
 			case ENET_EVENT_TYPE_RECEIVE: {
 
 
-				if (event.channelID==1) {
+				if (event.channelID==SYSCH_CONFIG) {
 					//some config message
 					ERR_CONTINUE( event.packet->dataLength < 8);
 
@@ -226,7 +226,7 @@ void NetworkedMultiplayerENet::poll(){
 					}
 
 					enet_packet_destroy(event.packet);
-				} else if (event.channelID==0){
+				} else if (event.channelID < SYSCH_MAX){
 
 					Packet packet;
 					packet.packet = event.packet;
@@ -258,7 +258,7 @@ void NetworkedMultiplayerENet::poll(){
 
 								ENetPacket* packet2 = enet_packet_create (packet.packet->data,packet.packet->dataLength,flags);
 
-								enet_peer_send(E->get(),0,packet2);
+								enet_peer_send(E->get(),event.channelID,packet2);
 							}
 
 						} else if (target<0) {
@@ -272,7 +272,7 @@ void NetworkedMultiplayerENet::poll(){
 
 								ENetPacket* packet2 = enet_packet_create (packet.packet->data,packet.packet->dataLength,flags);
 
-								enet_peer_send(E->get(),0,packet2);
+								enet_peer_send(E->get(),event.channelID,packet2);
 							}
 
 							if (-target != 1) {
@@ -289,7 +289,7 @@ void NetworkedMultiplayerENet::poll(){
 						} else {
 							//to someone else, specifically
 							ERR_CONTINUE(!peer_map.has(target));
-							enet_peer_send(peer_map[target],0,packet.packet);
+							enet_peer_send(peer_map[target],event.channelID,packet.packet);
 						}
 					} else {
 
@@ -369,16 +369,20 @@ Error NetworkedMultiplayerENet::put_packet(const uint8_t *p_buffer,int p_buffer_
 	ERR_FAIL_COND_V(connection_status!=CONNECTION_CONNECTED,ERR_UNCONFIGURED);
 
 	int packet_flags=0;
+	int channel=SYSCH_RELIABLE;
 
 	switch(transfer_mode) {
 		case TRANSFER_MODE_UNRELIABLE: {
 			packet_flags=ENET_PACKET_FLAG_UNSEQUENCED;
+			channel=SYSCH_UNRELIABLE;
 		} break;
 		case TRANSFER_MODE_UNRELIABLE_ORDERED: {
 			packet_flags=0;
+			channel=SYSCH_UNRELIABLE;
 		} break;
 		case TRANSFER_MODE_RELIABLE: {
 			packet_flags=ENET_PACKET_FLAG_RELIABLE;
+			channel=SYSCH_RELIABLE;
 		} break;
 	}
 
@@ -402,7 +406,7 @@ Error NetworkedMultiplayerENet::put_packet(const uint8_t *p_buffer,int p_buffer_
 	if (server) {
 
 		if (target_peer==0) {
-			enet_host_broadcast(host,0,packet);
+			enet_host_broadcast(host,channel,packet);
 		} else if (target_peer<0) {
 			//send to all but one
 			//and make copies for sending
@@ -416,18 +420,18 @@ Error NetworkedMultiplayerENet::put_packet(const uint8_t *p_buffer,int p_buffer_
 
 				ENetPacket* packet2 = enet_packet_create (packet->data,packet->dataLength,packet_flags);
 
-				enet_peer_send(F->get(),0,packet2);
+				enet_peer_send(F->get(),channel,packet2);
 			}
 
 			enet_packet_destroy(packet); //original packet no longer needed
 		} else {
-			enet_peer_send (E->get(), 0, packet);
+			enet_peer_send (E->get(), channel, packet);
 
 		}
 	} else {
 
 		ERR_FAIL_COND_V(!peer_map.has(1),ERR_BUG);
-		enet_peer_send (peer_map[1], 0, packet); //send to server for broadcast..
+		enet_peer_send (peer_map[1], channel, packet); //send to server for broadcast..
 
 	}
 

modules/enet/networked_multiplayer_enet.h

@@ -23,6 +23,13 @@ private:
 		SYSMSG_REMOVE_PEER
 	};
 
+	enum {
+		SYSCH_CONFIG,
+		SYSCH_RELIABLE,
+		SYSCH_UNRELIABLE,
+		SYSCH_MAX
+	};
+
 	bool active;
 	bool server;