src/debug.cpp

------------------------------------------------------------------
The ancient comment from the beginning of main.cpp is stored here.
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/*
=============================== NOTES ==============================
NOTE: Things starting with TODO are sometimes only suggestions.

NOTE: iostream.imbue(std::locale("C")) is very slow
NOTE: Global locale is now set at initialization

NOTE: If VBO (EHM_STATIC) is used, remember to explicitly free the
      hardware buffer (it is not freed automatically)

NOTE: A random to-do list saved here as documentation:
A list of "active blocks" in which stuff happens. (+=done)
	+ Add a never-resetted game timer to the server
	+ Add a timestamp value to blocks
	+ The simple rule: All blocks near some player are "active"
	- Do stuff in real time in active blocks
		+ Handle objects
		- Grow grass, delete leaves without a tree
		- Spawn some mobs based on some rules
		- Transform cobble to mossy cobble near water
		- Run a custom script
		- ...And all kinds of other dynamic stuff
	+ Keep track of when a block becomes active and becomes inactive
	+ When a block goes inactive:
		+ Store objects statically to block
		+ Store timer value as the timestamp
	+ When a block goes active:
		+ Create active objects out of static objects
		- Simulate the results of what would have happened if it would have
		  been active for all the time
		  	- Grow a lot of grass and so on
	+ Initially it is fine to send information about every active object
	  to every player. Eventually it should be modified to only send info
	  about the nearest ones.
	  	+ This was left to be done by the old system and it sends only the
		  nearest ones.

NOTE: Seeds in 1260:6c77e7dbfd29:
5721858502589302589:
	Spawns you on a small sand island with a surface dungeon
2983455799928051958:
	Enormous jungle + a surface dungeon at ~(250,0,0)

Old, wild and random suggestions that probably won't be done:
-------------------------------------------------------------

SUGG: If player is on ground, mainly fetch ground-level blocks

SUGG: Expose Connection's seqnums and ACKs to server and client.
      - This enables saving many packets and making a faster connection
	  - This also enables server to check if client has received the
	    most recent block sent, for example.
SUGG: Add a sane bandwidth throttling system to Connection

SUGG: More fine-grained control of client's dumping of blocks from
      memory
	  - ...What does this mean in the first place?

SUGG: A map editing mode (similar to dedicated server mode)

SUGG: Transfer more blocks in a single packet
SUGG: A blockdata combiner class, to which blocks are added and at
      destruction it sends all the stuff in as few packets as possible.
SUGG: Make a PACKET_COMBINED which contains many subpackets. Utilize
      it by sending more stuff in a single packet.
	  - Add a packet queue to RemoteClient, from which packets will be
	    combined with object data packets
		- This is not exactly trivial: the object data packets are
		  sometimes very big by themselves
	  - This might not give much network performance gain though.

SUGG: Precalculate lighting translation table at runtime (at startup)
      - This is not doable because it is currently hand-made and not
	    based on some mathematical function.
		- Note: This has been changing lately

SUGG: A version number to blocks, which increments when the block is
      modified (node add/remove, water update, lighting update)
	  - This can then be used to make sure the most recent version of
	    a block has been sent to client, for example

SUGG: Make the amount of blocks sending to client and the total
	  amount of blocks dynamically limited. Transferring blocks is the
	  main network eater of this system, so it is the one that has
	  to be throttled so that RTTs stay low.

SUGG: Meshes of blocks could be split into 6 meshes facing into
      different directions and then only those drawn that need to be

SUGG: Background music based on cellular automata?
      http://www.earslap.com/projectslab/otomata

SUGG: Simple light color information to air

SUGG: Server-side objects could be moved based on nodes to enable very
      lightweight operation and simple AI
	- Not practical; client would still need to show smooth movement.

SUGG: Make a system for pregenerating quick information for mapblocks, so
	  that the client can show them as cubes before they are actually sent
	  or even generated.

SUGG: Erosion simulation at map generation time
    - This might be plausible if larger areas of map were pregenerated
	  without lighting (which is slow)
	- Simulate water flows, which would carve out dirt fast and
	  then turn stone into gravel and sand and relocate it.
	- How about relocating minerals, too? Coal and gold in
	  downstream sand and gravel would be kind of cool
	  - This would need a better way of handling minerals, mainly
		to have mineral content as a separate field. the first
		parameter field is free for this.
	- Simulate rock falling from cliffs when water has removed
	  enough solid rock from the bottom

SUGG: For non-mapgen FarMesh: Add a per-sector database to store surface
      stuff as simple flags/values
      - Light?
	  - A building?
	  And at some point make the server send this data to the client too,
	  instead of referring to the noise functions
	  - Ground height
	  - Surface ground type
	  - Trees?

Gaming ideas:
-------------

- Aim for something like controlling a single dwarf in Dwarf Fortress
- The player could go faster by a crafting a boat, or riding an animal
- Random NPC traders. what else?

Game content:
-------------

- When furnace is destroyed, move items to player's inventory
- Add lots of stuff
- Glass blocks
- Growing grass, decaying leaves
	- This can be done in the active blocks I guess.
	- Lots of stuff can be done in the active blocks.
	- Uh, is there an active block list somewhere? I think not. Add it.
- Breaking weak structures
	- This can probably be accomplished in the same way as grass
- Player health points
	- When player dies, throw items on map (needs better item-on-map
	  implementation)
- Cobble to get mossy if near water
- More slots in furnace source list, so that multiple ingredients
  are possible.
- Keys to chests?

- The Treasure Guard; a big monster with a hammer
	- The hammer does great damage, shakes the ground and removes a block
	- You can drop on top of it, and have some time to attack there
	  before he shakes you off

- Maybe the difficulty could come from monsters getting tougher in
  far-away places, and the player starting to need something from
  there when time goes by.
  - The player would have some of that stuff at the beginning, and
    would need new supplies of it when it runs out

- A bomb
- A spread-items-on-map routine for the bomb, and for dying players

- Fighting:
  - Proper sword swing simulation
  - Player should get damage from colliding to a wall at high speed

Documentation:
--------------

Build system / running:
-----------------------

Networking and serialization:
-----------------------------

SUGG: Fix address to be ipv6 compatible

User Interface:
---------------

Graphics:
---------

SUGG: Combine MapBlock's face caches to so big pieces that VBO
      can be used
      - That is >500 vertices
	  - This is not easy; all the MapBlocks close to the player would
	    still need to be drawn separately and combining the blocks
		would have to happen in a background thread

SUGG: Make fetching sector's blocks more efficient when rendering
      sectors that have very large amounts of blocks (on client)
	  - Is this necessary at all?

SUGG: Draw cubes in inventory directly with 3D drawing commands, so that
      animating them is easier.

SUGG: Option for enabling proper alpha channel for textures

TODO: Flowing water animation

TODO: A setting for enabling bilinear filtering for textures

TODO: Better control of draw_control.wanted_max_blocks

TODO: Further investigate the use of GPU lighting in addition to the
      current one

TODO: Artificial (night) light could be more yellow colored than sunlight.
      - This is technically doable.
	  - Also the actual colors of the textures could be made less colorful
	    in the dark but it's a bit more difficult.

SUGG: Somehow make the night less colorful

TODO: Occlusion culling
      - At the same time, move some of the renderMap() block choosing code
        to the same place as where the new culling happens.
      - Shoot some rays per frame and when ready, make a new list of
	    blocks for usage of renderMap and give it a new pointer to it.

Configuration:
--------------

Client:
-------

TODO: Untie client network operations from framerate
      - Needs some input queues or something
	  - This won't give much performance boost because calculating block
	    meshes takes so long

SUGG: Make morning and evening transition more smooth and maybe shorter

TODO: Don't update all meshes always on single node changes, but
      check which ones should be updated
	  - implement Map::updateNodeMeshes() and the usage of it
	  - It will give almost always a 4x boost in mesh update performance.

- A weapon engine

- Tool/weapon visualization

FIXME: When disconnected to the menu, memory is not freed properly

TODO: Investigate how much the mesh generator thread gets used when
      transferring map data

Server:
-------

SUGG: Make an option to the server to disable building and digging near
      the starting position

FIXME: Server sometimes goes into some infinite PeerNotFoundException loop

* Fix the problem with the server constantly saving one or a few
  blocks? List the first saved block, maybe it explains.
  - It is probably caused by oscillating water
  - TODO: Investigate if this still happens (this is a very old one)
* Make a small history check to transformLiquids to detect and log
  continuous oscillations, in such detail that they can be fixed.

FIXME: The new optimized map sending doesn't sometimes send enough blocks
       from big caves and such
FIXME: Block send distance configuration does not take effect for some reason

Environment:
------------

TODO: Add proper hooks to when adding and removing active blocks

TODO: Finish the ActiveBlockModifier stuff and use it for something

Objects:
--------

TODO: Get rid of MapBlockObjects and use only ActiveObjects
	- Skipping the MapBlockObject data is nasty - there is no "total
	  length" stored; have to make a SkipMBOs function which contains
	  enough of the current code to skip them properly.

SUGG: MovingObject::move and Player::move are basically the same.
      combine them.
	- NOTE: This is a bit tricky because player has the sneaking ability
	- NOTE: Player::move is more up-to-date.
	- NOTE: There is a simple move implementation now in collision.{h,cpp}
	- NOTE: MovingObject will be deleted (MapBlockObject)

TODO: Add a long step function to objects that is called with the time
      difference when block activates

Map:
----

TODO: Flowing water to actually contain flow direction information
      - There is a space for this - it just has to be implemented.

TODO: Consider smoothening cave floors after generating them

TODO: Fix make_tree, make_* to use seed-position-consistent pseudorandom
	  - delta also

Misc. stuff:
------------
TODO: Make sure server handles removing grass when a block is placed (etc)
      - The client should not do it by itself
	  - NOTE: I think nobody does it currently...
TODO: Block cube placement around player's head
TODO: Protocol version field
TODO: Think about using same bits for material for fences and doors, for
	  example

SUGG: Restart irrlicht completely when coming back to main menu from game.
	- This gets rid of everything that is stored in irrlicht's caches.
	- This might be needed for texture pack selection in menu

TODO: Merge bahamada's audio stuff (clean patch available)

Making it more portable:
------------------------
 
Stuff to do before release:
---------------------------

Fixes to the current release:
-----------------------------

Stuff to do after release:
---------------------------

Doing currently:
----------------

======================================================================

*/
	Commit message (Expand)	Author	Age
*	Cleanup jthread and fix win32 build	sapier	2013-12-01
*	Always use builtin JThread library	kwolekr	2013-09-15
*	Omnicleanup: header cleanup, add ModApiUtil shared between game and mainmenu	Kahrl	2013-08-14
*	Migrate to STL containers/algorithms.	Ilya Zhuravlev	2013-03-11
*	Update Copyright Years	Sfan5	2013-02-24
*	Change Minetest-c55 to Minetest	PilzAdam	2013-02-24
*	Optimize headers	Perttu Ahola	2012-06-17
*	Switch the license to be LGPLv2/later, with small parts still remaining as GP...	Perttu Ahola	2012-06-05
*	Remove useless debug output (log at info level)	Perttu Ahola	2012-03-11
*	Clean up log messages everywhere	Perttu Ahola	2012-03-11
*	Improve debug stack printing interface	Perttu Ahola	2011-11-29
*	Prevent threadid_t from losing precision when casted on 64bit systems	q66	2011-08-11
*	fixed warnings reported by cppcheck	Perttu Ahola	2011-04-11
*	fixes toward mingw compatibility	Perttu Ahola	2011-02-10
*	local game connects to 127.0.0.1 instead of localhost (windows returns an ipv...	Perttu Ahola	2011-02-08
*	backing up some stuff	Perttu Ahola	2011-01-26
*	Added a more flexible path system (and fixed some minor stuff)	Perttu Ahola	2011-01-07
*	better debug output in segfaults and stack overflows in windows	Perttu Ahola	2010-12-27
*	some work-in-progress	Perttu Ahola	2010-12-22
*	license stuff (more to come)	Perttu Ahola	2010-11-29
*	Windows bug fixes	Perttu Ahola	2010-11-29
*	Initial files	Perttu Ahola	2010-11-27