Game rules

In this game each player commands a fleet of starships in the outer
space. The goal is to get the highest possible score by collecting point
bonuses and killing other players’ starships.

The game is played on a bidimensional cylindric universe. After
unfolding, this universe can be seen as the result of setting side by
side the same rectangle repeatedly along the vertical edge:

This repeated rectangle is an n × m grid of cells. Thus, any pair (i, j)
such that 0 ≤ i < n determines the position of a cell of the universe.
Note that two positions (i, j) and (i, j^(′)) such that
(j − j^(′)) mod m = 0 actually refer to the same cell. In what follows
we will refer to i and j as the row and the column of the position
(i, j), respectively.

Each cell of this universe may be empty or may contain:

- an asteroid, or

- a starship (commanded by one of the players), or

- a missile (previously shot by one of the starships), or

- a points bonus, or

- a missile bonus.

Players can look up the content of any cell of the universe during the
match.

Each player commands a number of starships which is a parameter of the
game. Each starship has a unique identifying number. The starships
commanded by the same player have consecutive identifiers.

Moving and shooting

At each round a player can command any of its starships to move in a
particular direction or to shoot a missile (but not the two at the same
time).

In general, the movement of the elements on the universe follows the
next rules:

- Starships may move horizontally, vertically or in diagonal. More
  precisely, in one movement a starship may increment its row by −1, 0
  or 1, and its column by 0, 1 or 2.

- By default, at each round a starship moves horizontally one column,
  i.e., its row remains the same and its column increases by 1.

- There is a window that the starships must remain within. This window
  is a rectangle of dimensions n × m_(W), where m_(W) ≤ m, and is
  dynamic: it moves forward one column per round. Therefore, at round r,
  its leftmost upper corner is at position (0, r), and its rightmost
  lower corner is at position (n − 1, r + m_(W) − 1). Moreover, a
  starship moving with the default direction remains always within the
  window.

  In the game viewer, the window is the part of the universe that will
  be shown. Since the window is taken as the system of reference for the
  visualization, it apparently does not move; similarly, starships
  moving by default apparently do not move either, etc.

- Asteroids and bonuses do not move.

- Missiles move horizontally two columns per round.

- Asteroids, bonuses and missiles may be outside the window. Note that
  in this case, although they cannot be viewed, they still exist on the
  universe.

A starship may shoot a missile if it has at least one in its stock
(which is then consumed). There is an initial number of missiles in the
stock of each starship. This stock can be enlarged by means of missile
bonuses. When a starship shoots, the new missile automatically moves
forward two columns from the starship position, and then immediately
after, the starship also moves with the default direction.

Collisions in a cell

When a starship and a bonus coincide in the same cell, the starship
consumes the bonus (increasing the number of available missiles if it is
a missile bonus, or getting more score if it is a point bonus). Once a
bonus is consumed, if possible it reappears on a random position outside
the window. This random position is guaranteed to be previously empty
and such that its surrounding square 5 × 5 is free from missiles or
starships.

In the other possible cases of collision, when two elements coincide in
the same cell both are destroyed. In particular, if one of the colliding
elements is a missile shot by a starship of player A and the other
element is a starship of a different player B, then A increases its
score.

When a starship is killed, it regenerates if possible after a number of
rounds, on a random position of the window. This random position is
guaranteed to be previously empty and such that its surrounding square
5 × 5 is free from missiles, starships or asteroids. The number of
available missiles is the same as before it died.

As a final consideration regarding collisions, when in a round a
starship (or a missile) moves from an initial cell to a final cell, in
some cases it is considered that it also passes certain intermediate
cells. More specifically:

1.  When a starship moves from cell (i, j) to cell (i + 1, j + 1), it
    also passes through cells (i + 1, j) and (i, j + 1). Similarly when
    it moves to cell (i − 1, j + 1).

2.  When a starship (or a missile) moves from cell (i, j) to cell
    (i, j + 2), it also passes through cell (i, j + 1).

3.  When a starship moves from cell (i, j) to cell (i + 1, j + 2), it
    also passes through cells (i, j + 1), (i + 1, j + 1), (i + 1, j) and
    (i, j + 2). Similarly when it moves to (i − 1, j + 2).

4.  In the other cases it does not pass through intermediate cells.

The exact order in which intermediate cells are visited can be looked up
in the map dir2all defined in Utils.cc.

Order of execution of instructions

After the instructions of all players are collected, the following
actions take place:

1.  First missiles are moved according to their rules.

2.  Next a random order is determined among the players, and the
    instructions for their starships are executed following this order.
    Invalid instructions (for example, moving outside the window limits)
    are ignored. If a starship receives more than one instruction, only
    the first one will be taken into account. Starships that have not
    received any instruction will move by default, in increasing order
    of identifier.

3.  If appropriate, dead starships and new bonuses (in this order) are
    regenerated.

Game parameters

A game is determined by following set of parameters:

@number_players()@: number of players in the game.

@number_rounds()@: number of rounds that will be played.

@number_rows()@: number of rows of the universe (and of the window).

@number_universe_columns()@: number of columns of the universe.

@number_window_columns()@: number of columns of the window.

@number_starships_per_player()@: number of starships for each player.

@number_starships()@: total number of starships.

@number_rounds_to_regenerate()@: number of rounds to wait before a
starship can regenerate.

@number_missile_bonuses()@: number of missile bonuses in the game.

@number_point_bonuses()@: number of point bonuses in the game.

@bonus_missiles()@: number of extra missiles obtained when consuming a
missile bonus.

@bonus_points()@: number of extra points obtained when consuming a point
bonus.

@kill_points()@: number of points obtained when killing a starship of
another player.

All these parameters can be accessed by the players during the game.

Programming

The first thing you should do is to download the source code. This
source code includes a C++ program that runs the matches and also an
HTML5/Javascript viewer to watch them in a nice animated format. Also, a
”Demo” player is provided to make it easier to start coding your own
player.

Running your first match

Here we will explain how to run the game under Linux, but a similar
procedure should work as well under Windows, Mac, FreeBSD,
OpenSolaris... The only requirements on your system are g++, make and a
modern browser like Mozilla Firefox or Chromium.

To run your first match, follow the next steps:

1.  Open a console and cd to the directory where you extracted the
    source code.

2.  Run make all to build the game and all the players. Note that the
    Makefile will identify as a player any file matching the expression
    ”AI*.cc”.

3.  The call to make should create an executable file called Game. This
    executable allows you to run a match as follows:

    ./Game Demo Demo Demo Demo < default.cnf > default.res

    Here, we are starting a match with 4 instances of the player ”Demo”
    (included with the source code), with the game configuration defined
    in ”default.cnf”. The output of this match will be stored in
    ”default.res”.

4.  To watch the match, open the viewer (viewer.html) with your browser
    and load the ”default.res” file.

A script run.sh for carrying out steps 2-4 automatically is also
provided.

Use the --help option of Game to see a list of all options you can use.
For instance, the option --list will show a list with all the available
player names.

If needed, remember you can run make clean to delete the executable and
all object files and start over the build.

Adding your player

To create a player, copy the file AINull.cc (an empty player that is
provided as a template) to a new file with the same name format
(AIWhatever.cc).

Then, edit the file you just created and change the playername line to
your own player name, as follows:

@#define PLAYER_NAME Whatever@

The name you choose for your player must be unique, non-offensive and
less than 12 letters long. It will be used to define a new class
@PLAYER_NAME@, which will be referred to below as your player class. The
name will be shown as well when viewing the matches and on the website.

Now you can start implementing the method @play()@. This method will be
called every round and is where your player should decide what to do,
and do it. Of course, you can define auxiliary methods and variables
inside your player class, but the entry point of your code will always
be this @play()@ method.

From your player class you can also call functions to access the board
state, as defined in the @Board@ class in Board.hh, and to command your
units, as defined in the @Action@ class in Action.hh. These functions
are made available to your code using multiple inheritance via the class
@Player@ in Player.hh . The documentation on the available functions can
be found in the aforementioned header files of each class. You can also
examine the code of the “Demo” player in AIDemo.cc as an example of how
to use these functions. Finally, it may be worth as well to have a look
at the file Utils.hh for useful data structures.

Note that you should not modify the @factory()@ method from your player
class, nor the last line that adds your player to the list of available
players.

Playing against the Dummy player

To test your strategy against the Dummy player, we provide the AIDummy.o
object file. This way you still will not have the source code of our
Dummy, but you will be able to add it as a player and compete against it
locally.

To add the Dummy player to the list of registered players, you will have
to edit the Makefile file and set the variable DUMMY_OBJ to the
appropriate value. Remember that object files contain binary
instructions targeting a specific machine, so we cannot provide a
single, generic file. If you miss an object file for your architecture,
contact us and we will try to supply it.

Pro tip: You can ask your friends for the object files of their players
and add them to the Makefile too!

Restrictions when submitting your player

Once you think your player is strong enough to enter the competition,
you should submit it to the Jutge.org website (https://www.jutge.org).
Since it will run in a secure environment to prevent cheating, some
restrictions apply to your code:

- All your source code must be in a single file (AIWhatever.cc).

- Your code cannot use global variables (use attributes in your class
  instead).

- You are only allowed to use standard libraries like vector, map,
  cmath...

- Your code cannot open files nor do any other system calls (threads,
  forks...).

- Your CPU time and memory usage will be limited when executed on
  Jutge.org. The time limit is 1 second for the execution of the entire
  game. If the time limit has been exceeded (or if the execution of your
  code aborts), your player will be frozen and will not admit further
  instructions any more.

- Your program should not write to @cout@ nor read from @cin@. You can
  write debug information to @cerr@ (but remember that doing so on the
  code you upload can waste part of your limited CPU time).

Tips

- Read only the headers of the classes in the provided source code. Do
  not worry about the private parts nor the implementation.

- Start with simple strategies, easy to code and debug, since this is
  exactly what you will need at the beginning.

- Define basic auxiliary methods, and make sure they work properly.

- Try to keep your code clean. Then it will be easier to change it and
  to add new strategies.

- As usual, compile and test your code often. It is much easier to trace
  a bug when you only have changed few lines of code.

- Use cerrs to output debug information and add asserts to make sure the
  code is doing what it should do. Remember to remove (or comment out)
  the cerrs before uploading your code to Jutge.org, because they make
  the execution slower.

- When debugging a player, remove the cerrs you may have in the other
  players’ code, to make sure you only see the messages you want.

- By using commands like grep in Linux you can filter the output that
  Game produces.

- Switch on the DEBUG option in the Makefile, which will allow you to
  get useful backtraces when your program crashes. There is also a
  PROFILE option you can use for code optimisation.

- If using cerr is not enough to debug your code, learn how to use
  valgrind, gdb, ddd or any other debugging tool. They are quite useful!

- You can analyse the files that the program Game produces as output,
  which describe how the board evolves after each round.

- Keep a copy of the old versions of your player. When a new version is
  ready, make it fight against the previous ones to measure the
  improvement.

- Before competing with your classmates, focus on qualifying and
  defeating the ”Dummy” player.

- Make sure your program is fast enough: the CPU time you are allowed to
  use is rather short.

- Try to figure out the strategies of your competitors by watching
  matches. This way you can try to defend against them or even improve
  them in your own player.

- DO NOT GIVE YOUR CODE TO ANYBODY. Not even an old version. We are
  using plagiarism detectors to compare pairwise all submissions
  (including programs from previous competitions). However, you can
  share the compiled .o files.

- Do not wait till the last minute to submit your player. When there are
  lots of submissions at the same time, it will take longer for the
  server to run the matches, and it might be too late!

- Most of the game parameters (number of rounds, ...) will not change,
  but if your strategy can adjust to them, you will be extra-safe in
  case some changes are needed.

- You can submit new versions of your program at any time.

- If you create your own board for the game, send it to us before the
  competition starts and maybe we will include it!

- And again: Keep your code simple, build often, test often. Or you will
  regret.
