Work on basic logging framework.

library/PolyVoxCore/include/Log.h

@@ -5,6 +5,33 @@
 
 #include <string>
 
-POLYVOXCORE_API extern void (*logImpl)(std::string);
+//Note: The functions in this file are not for the user to call - they are 
+//intended for internal use only. The only exception is that you may set the
+//logHandler pointer to point at your own handling funtion for printing, etc.
+
+namespace PolyVox
+{
+	enum LogSeverity
+	{
+		LS_DEBUG,
+		LS_INFO,
+		LS_WARN,
+		LS_ERROR
+	};	
+
+	POLYVOXCORE_API extern void (*logHandler)(std::string, int severity);
+}
+
+//Debug severity messages are only used if we are a debug build
+#ifdef _DEBUG
+	#define POLYVOX_LOG_DEBUG(message) if(logHandler){logHandler(message, LS_DEBUG);}
+#else
+	#define POLYVOX_LOG_DEBUG(message)
+#endif
+
+//Other severity levels work in both debug and release
+#define POLYVOX_LOG_INFO(message) if(logHandler){logHandler(message, LS_INFO);}
+#define POLYVOX_LOG_WARN(message) if(logHandler){logHandler(message, LS_WARN);}
+#define POLYVOX_LOG_ERROR(message) if(logHandler){logHandler(message, LS_ERROR);}
 
 #endif