## Logging
* Can log to separate channels, for example one channel for each
  subsystem
  * 'Channels' can be different color printouts, separate files, 
  separate TTY consoles, etc.
  * Naughty Dog uses http://redis.io to log to a web based interface
* Use log verbosity to control how much debug info is printed out
* Can use bitmasks to set the log channel or verbosity (1 bit per channel/
  verbosity)
  * Test if to print out the log message if the bit for that level is
    enabled
* Important to 'flush' printouts to files to ensure the last message before
  crashes are actually logged
  * However, flushing can be expensive so there is a tradeoff

## Debug Drawing
* Useful to have support for simple drawing primitives to aid in 
  graphical debugging, especially in 3d, such as
  * lines
  * spheres
  * points (small cross/box as single pixel difficult to see)
  * coordinate axis (x,y,z pointing lines)
  * bounding boxes
  * formatted text
* Example images:
![Debug Draw Image 1](debug_img_1.png)
![Debug Draw Image 2](debug_img_2.png)
![Debug Draw Image 3](debug_img_3.png)
![Debug Draw Image 4](debug_img_4.png)

## In Game Menu/Debug Console
* Useful to have HUD or in-game console to toggle flags, run game in
  slow motion, set values, execute commands, etc.
* Usually bringing up the HUD pauses the game, then unpauses after exiting
  the menu
![Debug Menu Image 4](debug_menu_1.png)

## In Game Time-profiling/FPS calc
* For testing the speeds of various functions or code sections
  * Can implement hierarchical programming 
   (Call-stack, e.g. function a calls function b, etc.)
  * This is helpful to narrow down high-cpu functions from top level
* Useful to break down both number of times called and time spent in call
  call
  * determine if number of calls is low but CPU time high, or 
  * number of calls high but CPU time low
* Example impl:

		while !(quitGame)
		{
			{
				PROFILE(SID("Poll Joypad"));
				PollJoypad();
			}
			{
				PROFILE(SID("Game Object Update"));
				UpdateGameObjects();
			}
			{
				PROFILE(SID("Physics"));
				Physics();
			}
			...
		}

		struct AutoProfile
		{
			AutoProfile(const char *name)
			{
				m_name = name;
				m_startTime = getTime();
			}
			~AutoProfile()
			{
				m_stopTime = getTime();
				m_totalTime = m_stopTime - m_startTime;
				
				g_profileManager.storeSample(m_name, m_totalTime);
			}
		}

## Memory Usage Tracking

* This is hard
* Things to think about:
  * Controlling/Tracking memory in third party libraries
  * Video Memory vs. System RAM memory
  * Memory allocators/types
    * E.g. our custom stack allocators or other types discussed earlier
* On consoles, SDKs can come with more memory than is acually available
  on the system
  * In this case, must keep track of when memory would run out on a real
    system
![Naughty Dog Memory Display 1](memory_1.png)
![Naughty Dog Memory Display 2](memory_2.png)

## Other useful in-game debugging
* Cheats, such as making your character free-fly around the level
* Unlimited Ammo/Invincibility
* Screen shots or gameplay recording