Add an example on how to create custom logger

Also export level2str() in Logger for external use.

Author: xlz

examples/protonect/Protonect.cpp

@@ -33,7 +33,7 @@
 #include <libfreenect2/threading.h>
 #include <libfreenect2/registration.h>
 #include <libfreenect2/packet_pipeline.h>
-#include <libfreenect2/logging.h>
+#include <libfreenect2/logger.h>
 #ifdef LIBFREENECT2_WITH_OPENGL_SUPPORT
 #include "viewer.h"
 #endif
@@ -46,6 +46,29 @@ void sigint_handler(int s)
   protonect_shutdown = true;
 }
 
+//The following demostrates how to create a custom logger
+#include <fstream>
+#include <cstdlib>
+class MyFileLogger: public libfreenect2::Logger
+{
+private:
+  std::ofstream logfile_;
+public:
+  MyFileLogger(const char *filename)
+    : logfile_(filename)
+  {
+    level_ = Debug;
+  }
+  bool good()
+  {
+    return logfile_.good();
+  }
+  virtual void log(Level level, const std::string &message)
+  {
+    logfile_ << "[" << libfreenect2::Logger::level2str(level) << "] " << message << std::endl;
+  }
+};
+
 int main(int argc, char *argv[])
 {
   std::string program_path(argv[0]);
@@ -61,6 +84,9 @@ int main(int argc, char *argv[])
   libfreenect2::Freenect2 freenect2;
   // create a console logger with debug level (default is console logger with info level)
   libfreenect2::setGlobalLogger(libfreenect2::createConsoleLogger(libfreenect2::Logger::Debug));
+  MyFileLogger *filelogger = new MyFileLogger(getenv("LOGFILE"));
+  if (filelogger->good())
+    libfreenect2::setGlobalLogger(filelogger);
 
   libfreenect2::Freenect2Device *dev = 0;
   libfreenect2::PacketPipeline *pipeline = 0;

examples/protonect/include/libfreenect2/logger.h

@@ -47,6 +47,7 @@ class LIBFREENECT2_API Logger
     Debug = 4,
   };
   static Level getDefaultLevel();
+  static std::string level2str(Level level);
 
   virtual ~Logger();
 

examples/protonect/src/logging.cpp

@@ -74,7 +74,7 @@ Logger::Level Logger::level() const
   return level_;
 }
 
-std::string level2str(const Logger::Level &l)
+std::string Logger::level2str(Level l)
 {
   switch(l)
   {