Rather than creating a thread to read datagrams, just set the socket to

nonblocking mode and check it before simulating.  This addresses one aspect
of the lack of synchronization on AgentList, but there are other issues...

interface/src/main.cpp

@@ -39,8 +39,6 @@
 #include <ifaddrs.h>
 #endif
 
-#include <pthread.h>
-
 #include <glm/glm.hpp>
 #include <glm/gtc/matrix_transform.hpp>
 #include <glm/gtc/type_ptr.hpp>
@@ -88,10 +86,7 @@ using namespace std;
 void reshape(int width, int height); // will be defined below
 void loadViewFrustum(ViewFrustum& viewFrustum);  // will be defined below
 
-
+unsigned char incomingPacket[MAX_PACKET_SIZE];
-pthread_t networkReceiveThread;
-bool stopNetworkReceiveThread = false;
-
 int packetCount = 0;
 int packetsPerSecond = 0; 
 int bytesPerSecond = 0;
@@ -429,8 +424,6 @@ void terminate () {
     #ifndef _WIN32
     audio.terminate();
     #endif
-    stopNetworkReceiveThread = true;
-    pthread_join(networkReceiveThread, NULL);
     
     exit(EXIT_SUCCESS);
 }
@@ -1492,14 +1485,12 @@ void key(unsigned char k, int x, int y)
 }
 
 //  Receive packets from other agents/servers and decide what to do with them!
-void *networkReceive(void *args)
+void networkReceive()
 {    
     sockaddr senderAddress;
     ssize_t bytesReceived;
-    unsigned char *incomingPacket = new unsigned char[MAX_PACKET_SIZE];
 
-    while (!stopNetworkReceiveThread) {
+    while (AgentList::getInstance()->getAgentSocket().receive(&senderAddress, incomingPacket, &bytesReceived)) {
-        if (AgentList::getInstance()->getAgentSocket().receive(&senderAddress, incomingPacket, &bytesReceived)) {
         packetCount++;
         bytesCount += bytesReceived;
         
@@ -1524,11 +1515,6 @@ void *networkReceive(void *args)
     }
 }
 
-    delete[] incomingPacket;
-    pthread_exit(0); 
-    return NULL;
-}
-
 void idle(void) {
     timeval check;
     gettimeofday(&check, NULL);
@@ -1560,6 +1546,9 @@ void idle(void) {
         //
         updateAvatar(deltaTime);
 		
+		// read incoming packets from network
+		networkReceive();
+		
         //loop through all the other avatars and simulate them...
         AgentList* agentList = AgentList::getInstance();
         for(AgentList::iterator agent = agentList->begin(); agent != agentList->end(); agent++) {
@@ -1703,6 +1692,7 @@ int main(int argc, const char * argv[])
         listenPort = atoi(portStr);
     }
     AgentList::createInstance(AGENT_TYPE_AVATAR, listenPort);
+    AgentList::getInstance()->getAgentSocket().setBlocking(false);
     
     gettimeofday(&applicationStartupTime, NULL);
     const char* domainIP = getCmdOption(argc, argv, "--domain");
@@ -1785,10 +1775,6 @@ int main(int argc, const char * argv[])
         printLog("Local Voxel File loaded.\n");
 	}
     
-    // create thread for receipt of data via UDP
-    pthread_create(&networkReceiveThread, NULL, networkReceive, NULL);
-    printLog("Network receive thread created.\n");
-    
     glutTimerFunc(1000, Timer, 0);
     glutMainLoop();
 

libraries/shared/src/UDPSocket.cpp

@@ -119,7 +119,7 @@ unsigned short loadBufferWithSocketInfo(char *addressBuffer, sockaddr *socket) {
     }
 }
 
-UDPSocket::UDPSocket(int listeningPort) {
+UDPSocket::UDPSocket(int listeningPort) : blocking(true) {
     init();
     // create the socket
     handle = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
@@ -191,6 +191,18 @@ bool UDPSocket::init() {
     return true;
 }
 
+void UDPSocket::setBlocking(bool blocking) {
+    this->blocking = blocking;
+
+#ifdef _WIN32
+    u_long mode = blocking ? 0 : 1;
+    ioctlsocket(handle, FIONBIO, &mode);
+#else
+    int flags = fcntl(handle, F_GETFL, 0);
+    fcntl(handle, F_SETFL, blocking ? (flags & ~O_NONBLOCK) : (flags | O_NONBLOCK));
+#endif
+}
+
 //  Receive data on this socket with retrieving address of sender
 bool UDPSocket::receive(void *receivedData, ssize_t *receivedBytes) {
     

libraries/shared/src/UDPSocket.h

@@ -23,12 +23,15 @@ class UDPSocket {
         UDPSocket(int listening_port);
         ~UDPSocket();
         bool init();
+        void setBlocking(bool blocking);
+        bool isBlocking() { return blocking; }
         int send(sockaddr *destAddress, const void *data, size_t byteLength);
         int send(char *destAddress, int destPort, const void *data, size_t byteLength);
         bool receive(void *receivedData, ssize_t *receivedBytes);
         bool receive(sockaddr *recvAddress, void *receivedData, ssize_t *receivedBytes);
     private:
         int handle;
+        bool blocking;
 };
 
 bool socketMatch(sockaddr *first, sockaddr *second);