Fix configuration for Snowballs

--HG--
branch : develop

code/snowballs2/bin/snowballs_client_default.cfg

@@ -57,6 +57,9 @@ ScreenFull = 1;
 // Start position of the player (the z is always 0)
 StartPoint = { 1840.0, -970.0, 0.0 };
 
+// Anti-Aliasing
+EnableFXAA = 0;
+
 
 //////////////////////////////////////////////////////////////////////////////
 // HMD Variables /////////////////////////////////////////////////////////////

code/snowballs2/client/src/configuration.cpp

@@ -37,7 +37,15 @@ namespace SBCLIENT {
 void CConfiguration::setAndCallback(const std::string &varName, void (*cb)(CConfigFile::CVar &var))
 {
 	ConfigFile->setCallback(varName, cb);
-	cb(*ConfigFile->getVarPtr(varName));
+	CConfigFile::CVar *varPtr = ConfigFile->getVarPtr(varName);
+	if (!varPtr)
+	{
+		nlwarning("Missing config variable '%s'", varName.c_str());
+	}
+	else
+	{
+		cb(*varPtr);
+	}
 }
 
 void CConfiguration::dropCallback(const std::string &varName)