CISC 124 Assignment 3
---------------------

Here's a game without much purpose.  You can move tiles around on a
grid and make a ball move through them.  Each tile has a passage
through which the ball can pass; some passages are straight and others
are curved.

You can drag tiles with the mouse.  You can also type these keys:

   'g'   start or stop the ball ('g' for 'go')
   'r'   reverse the ball
   '+'   speed up the ball
   '-'   slow down the ball

The initial set of tiles is defined in a board configuration file
called 'initialBoard'.  The file looks like

   c r
   t11 t12 t13 ... t1c
   t21 t22 t23 ... t2c
   t31 t32 t33 ... t3c
   ... ... ... ... ...
   tr1 tr2 tr3 ... trc

where c and r and the x dimension (columns) and y dimension (rows),
respectively, and txy is the tile in cell (x,y).  A tile can be one of

  hz   horizontal
  vt   vertical
  ul   elbow in upper-left corner
  ur   elbow in upper-right corner
  lr   elbow in lower-right corner
  ll   elbow in lower-left corner
  -    no tile

Note that any cell can have a hyphen '-' to indicate that no tile is
initially placed in that cell.

See the files 'initialBoard' and 'initialBoard2' for some examples.

Step 1
------

Get the program running.  Try the 'initialBoard'.  Here's a challenge:
Start the ball rolling by pressing 'g'.  Then quickly rearrange the
pieces while the ball is moving so that the ball loops around
continuously.  If you're too slow, the ball will get stuck.  You can
restart it by pressing 'g' again (you might have to reverse it first,
by pressing 'r').  This challenge is easier is you've got a slow
computer.

Look at the code and understand it at a high level.  You should
understand how the events get handled, and how the tiles are stored.
But you don't need to know how the tiles are drawn, or exactly how the
ball is moved through them.

Step 2
------

Make the following changes:

  A. Add GUI buttons that have the same functionality as the 'g', 'r', '+',
     and '-' keys described above.

  B. Modify the code so that the Piece (i.e. tile) currently occupied
     by the ball is highlighted in a different colour.  You should 
     store the Piece colour with the Piece, and change it when the ball 
     enters the Piece.  Modify the Piece::draw() method to use the correct
     colour.  Update your colours in the Board.moveBall() method, where
     it says "YOUR CODE HERE".

     Add a checkbox to your GUI to allow the highlighting to be turned 
     on or off.

  C. Modify the game so that it becomes a puzzle.  The puzzle is to get
     the ball to move from a start tile to a goal tile.

     Add an Blocker Piece which extends the Piece class.  A Blocker
     is drawn as a solid tile.  This is done already by the Piece class,
     so you don't need to do any graphics calls.  The Blocker should
     not be movable, so you'll need to add an 'immovable' flag to the
     base Piece class, and take that into account when the mouse is
     pressed.  This can be done with a single extra line of code in
     the mousePresseed() method.  Modify the PieceList class to include
     Blocker pieces, which are denoted with a capital 'B' in the 
     board configuration file.  The ball can't pass through a Blocker,
     so you don't need to handle any ball movement.

     Add two more Pieces: a Start and a Goal.  Each Piece should extend one
     of the horizontal StraightPieces, so you don't won't need do any 
     graphics or handle the ball movement.  You'll have to initially 
     position the ball in middle of the Start piece, if a Start piece 
     exists.  Both Start and Goal pieces are immovable.  They are denoted 
     as 'S' and 'G' in the board configuration file.

     Show a message in your GUI when the ball reaches the Goal.

Step 3
------

We will have a contest, separately within each of the two sections of
CISC 124, for the best additional modifications to the tile program.
The best modifications will be shown in class, and a small prize will
be awarded in each section of CISC 124.  You do not have to enter the
contest; you can get full marks on this assignment if you only
complete Step 2.

Here are some ideas for additional modifications.  Don't let this
list limit your imagination!

 - Provide a timer to show how fast the player gets from the start to
   the goal. The timer would count up in *real* time from the time the
   player starts the ball, to the time the ball reaches the goal.

 - Make this into a construction game by providing another panel from
   which new pieces can be created.  For example, you might drag a
   piece from that other panel into your main panel.  Pieces in that
   other panel would be 'replenished' immediately.

 - (Challenging) Create new pieces.  For example, create a crossover
   piece which allows the ball to move through it horizontally *or*
   vertically.  Or create a 'random' piece which has an empty interior
   and which directs the ball to a random exit.  If you want to
   play with graphics, add an animated mechanism inside the piece and
   have the mechanism move as the ball passes through.

 - Make certain pieces hide the ball as it passes through them.  With
   this feature, you could cluster some of these hiding pieces.  The
   player would have to deduce what pieces are inside the cluster by 
   sending the ball into the cluster and seeing where it comes out ... 
   from several different entry points.  Providing crossover and random 
   pieces makes the puzzle harder.

Submit with your code a CONTEST_README file that explains what
modifications you made.  In that file (which should be plain text)
describe why your modifications are interesting, difficult, fun, or
whatever.