TRIPPPIN
                              (second release)

This is a game based on a commercial board game that was called TRIPPPLES ®,
which was marketed by some game company years ago.  I do not remember who
sold it and I cannot find a copy of the game.  If somebody knows where it
came from please tell me.  This version is based solely on memory of having
played the game back in the seventies or whenever it was.

The game is played on an eight by eight grid of square tiles which are placed
in random positions except for six special ones that go in fixed positions. 
There are two players, each having one playing token that moves from square
to square.  They start side by side on two tiles with square shapes in them,
in the middle of the bottom edge of the board.  The four other fixed squares
are marked with circles, and they are located near each corner of the board,
one square inward from the edges.  The object of the game is to move your
piece from the starting square to the nearest circle, from there to the
circle above that, across the top to the opposite circle, down the other side
to the circle nearest where your opponent started, and finally to the square
your opponent started on.  Whoever gets around the course first wins.  A move
consists of moving your piece to one of the eight squares immediately next to
it, vertically, horizontally, or diagonally.

The tricky (and fun) part is this:  most of the other squares have arrows
marked on them.  Each has arrows pointing in three directions, out of eight
possible directions (up, upper right, right, lower right, etc).  These arrows
limit the directions in which YOUR OPPONENT is allowed to move, when you are
on that square.  If you make a move onto a square that has arrow pointing
downward, leftward, and to the upper right, then the only moves your opponent
is allowed to make in response are to the squares immediately downward,
leftward, or to the upper right of the square he's on.

When you are on a square that does not have arrows (the two starting squares,
the four circles, or two blank squares which are randomly placed), then your
opponent can make any of the eight moves.  BUT he cannot move off the edge of
the board, and he cannot move onto the same square you are on.  So the number
of legal moves available is often less than the eight or three allowed by the
other player's square.  In fact sometimes a player is left with no legal move
at all.  In this case the other player wins.  Strategically, it is dangerous
to be on the edge of the board, especially to be in a corner, because of the
possibility that your opponent might find a move which "pushes you off the
edge", leaving no legal moves.

To play the game, run the program TRIPPPIN from Workbench or CLI.  It will
open a window on the Workbench screen, and fill in the 64 squares with a
random arrangement of arrows.  (Each possible combination of three arrows out
of a possible eight is present exactly once.)  The program will automatically
detect whether the workbench screen is interlaced or not, and adjust the
proportions of the squares to suit.  It will show the two pieces on the
starting squares, and will show the present status of the game to the right
of the board.  At the top it shows whose turn it is to move.  This is
indicated by the color of the piece.  They are the same shape but the one on
the right is color 3 (orange in the default 1.2/1.3 workbench) and the one on
the left is color 0 (blue in default 1.x).  Below that it says either "MAKE A
MOVE" or "thinking..." depending on whether the piece to move next is
controlled by a human player or by the computer.  This is written on a
background of the color of the piece due to move.  This text can also read
"CAN'T MOVE!" if a player has no legal move, or "Game over." if the other
player reaches the final goal.

Below that it shows the directions in which this piece can legally move,
displayed as a set of arrows similar to a square of the board.  Below that it
says "Try to reach the flashing X of your piece's color."  Two X's, one the
color of each piece, are blinking on the circles that the pieces have to
reach.  When you reach the circle that X is blinking in, it moves to the next
circle you have to get to, or to the square your opponent started on if you
have reached the last circle.  If you reach that, you win.  When someone wins
the area where the words "Try to reach the flashing X ..." were gets filled
in with an announcement of who won.

To move a piece, click the mouse on it and drag it to the square you want to
move to.  If the move is illegal, the screen will flash ("beep") and the
piece will go back where it was.  Otherwise it becomes the other player's
turn.

When the game first starts, the right hand piece (orange by default) is under
human control and the other piece is played by the computer.  When your piece
is moved the computer will think a bit and then move the other one.  How long
it thinks depends on the difficulty level you set.

Control of the difficulty level, and of whether each piece is human or
computer controlled, is done with a menu.  The menu contains first an item
for each piece, with a submenu that lets you pick "Human" or "Computer", with
a checkmark showing the current selection.  Then there's an item for
difficulty level, with a submenu giving you choices from one (easy) to nine
(takes forever).  The level starts at three.  A checkmark shows the current
level.  The computer uses a simple lookahead strategy.  At level one it looks
at each move only to see which move gets it closest to its goal.  At level
two it looks at how close you can get for each move it makes.  At level three
it checks how close it can get after each move you might make in response to
each of its possible moves.  And so on.  The higher the level you set, the
longer it takes to think, though the delay is hardly noticeable below level
five or six.  Don't be discouraged if you have a hard time beating even a
moderate difficulty level; I do too.  Most human players hardly look further
than level two (if that) most of the time anyway.  Often a moderate level
setting plays just about as well as a high level one.

The next menu item lets you choose whether the computer player is allowed to
repeat a sequence of moves forever.  If "Prevent loops" is checked, then if
recent moves by both sides have been repeated two complete times in a loop,
the computer player is not allowed to continue another repetition unless
there is no other legal move.  Loops more than twenty turns long will not be
noticed.  There is no restriction of looping for human players.  If you set
the computer to play against itself loop prevention is essential or it will
probably get stuck before finishing a game.  If you want to play against the
toughest possible computer opponent then turn off loop prevention.

Below that is "Suggest a move", with keyboard shortcut right-Amiga S.  When
you select this (if it is not the computer's turn) it will show you which
square would be the best move for you, in its opinion.  How good a suggestion
this is depends on how long you wait before asking.  Even if you only wait a
couple of seconds it will probably give you an answer based on looking at
least six levels ahead.  It will show the suggested square with a bunch of
colored dots moving around a square outline.  Hey ... "Tripppin Has Ants."

Below that on the menu is the option to take back your last move.  You can
use the keyboard shortcut right-Amiga T for this.  It undoes the last move
made by a human controlled piece, and any computer move made after it. 
Pressing it again undoes the move before, and so on.  A maximum of forty
moves can be undone.  Nothing happens if both pieces are being played by
computer.

Below that is "Restart the game".  It will reshuffle the arrow squares and
put the pieces in their starting positions.  This time the other piece moves
first (it changes each time you restart).  Settings of difficulty level and
human / computer control of each piece remain unchanged.

Last is "Quit the game".  You can also quit by clicking the closebox or (if
it was run from CLI) pressing control-C in the CLI window it's running from.

Hopefully this will work in AmigaDOS 2.0 and later ... I went to the trouble
of making it pay attention to the size of the current workbench font so it
can position text nicely.  It can manage font sizes up to 13, or even 15 a
bit clumsily ... or double that on an interlaced workbench.  I hope somebody
lets me know if it doesn't work under 2.0 AmigaDOS.

The source code for this game contains plenty of possibly useful example
material.  I wrote it for practice with graphics.library and with intuition
event loops (since almost everything else I've been writing is CLI oriented),
and it contains useful examples of Bobs, animated sprites (not VSprites
though), basic multitasking (the lookahead thinking is done in a separate
task so that the main program can be immediately responsive to user input), a
tiny interrupt server (which is now present only because I'm too lazy to
remove it now that it's no longer really needed), and menu and mouse input. 
This code, though not necessarily the actual game it plays (which I did not
invent) is in the public domain.  Tripppin is by

        Paul Kienitz
	6430 San Pablo ave
	Oakland, CA  94608
	USA

I can probably be reached on one of the following BBSes:
    Winners Circle 415-845-4812
    Triple-A       415-222-9416
    FAUG           415-595-2479
    The Mission    415-967-2021

The differences between this second release of Tripppin and the first release
are:  two small bugs were fixed, the sprites were more obnoxious before (they
didn't turn off when you were doing other stuff), and you couldn't turn off
loop prevention in the first version.  Also I accidentally left the file
"trip.h" out of that distribution!