added preliminary shared memory physics client/server

fix a bug in CommonMultiBodyBase: don't use data if it hasn't been allocated

examples/SharedMemory/SharedMemoryInterface.h

@@ -0,0 +1,73 @@
+#ifndef SHARED_MEMORY_INTERFACE_H
+#define SHARED_MEMORY_INTERFACE_H
+
+#define SHARED_MEMORY_KEY 12345
+#define SHARED_MEMORY_MAGIC_NUMBER 64738
+#define SHARED_MEMORY_MAX_COMMANDS 64
+
+enum SharedMemoryServerCommand{
+    CMD_URDF_LOADING_COMPLETED,
+    CMD_URDF_LOADING_FAILED,
+    
+    CMD_SERVER_STATE_UPDATE_COMPLETED,
+    CMD_STEP_FORWARD_SIMULATION_COMPLETED,
+    CMD_MAX_SERVER_COMMANDS
+};
+
+enum SharedMemoryClientCommand{
+    CMD_LOAD_URDF,
+    CMD_STATE_UPDATED,
+    CMD_STEP_FORWARD_SIMULATION, //includes CMD_REQUEST_STATE
+    CMD_MAX_CLIENT_COMMANDS
+};
+
+#define SHARED_MEMORY_SERVER_TEST_C
+#define MAX_DEGREE_OF_FREEDOM 1024
+#define MAX_NUM_SENSORS 1024
+#define MAX_URDF_FILENAME_LENGTH 1024
+
+struct CommandArguments
+{
+    double m_deltaTimeInSeconds;
+    char m_urdfFileName[MAX_URDF_FILENAME_LENGTH];
+};
+
+struct SharedMemoryExampleData
+{
+    int m_magicId;
+    int m_clientCommands[SHARED_MEMORY_MAX_COMMANDS];
+    int m_serverCommands[SHARED_MEMORY_MAX_COMMANDS];
+    
+    int m_numClientCommands;
+    int m_numProcessedClientCommands;
+    
+    int m_numServerCommands;
+    int m_numProcessedServerCommands;
+    
+    
+    double m_stateQ[MAX_DEGREE_OF_FREEDOM];
+    double m_stateQdot[MAX_DEGREE_OF_FREEDOM];
+    double m_stateSensors[MAX_NUM_SENSORS];//these are force sensors and IMU information
+    
+    CommandArguments m_clientCommandArguments[SHARED_MEMORY_MAX_COMMANDS];
+    CommandArguments m_serverCommandArguments[SHARED_MEMORY_MAX_COMMANDS];
+    
+};
+
+#define SHARED_MEMORY_SIZE sizeof(SharedMemoryExampleData)
+
+
+
+
+class SharedMemoryInterface
+{
+	public:
+	virtual ~SharedMemoryInterface()
+	{
+	}
+	
+	virtual void*	allocateSharedMemory(int key, int size) =0;
+	virtual void releaseSharedMemory(int key, int size) =0;
+};
+#endif
+