IOCCC

The International Obfuscated C Code Contest

Supplemental Info

Playing the game is very simple but because there are many different modes I have included much more than just the input keys and a few printouts of the game. For normal play you probably don’t even need this file at all unless it be for the input keys.

1. Testing terminal environment/capabilities 2. Input keys 3. Gameplay * The initial screen * Playing the game * Walls * Cannibalism * Stretching (shedding) * Winning * Quitting 4. Gameplay modes * Photosensitive epilepsy/Stimulation overload trigger warnings * Drawing / Practice mode * Computer playing / Automatic mode (Photosensitive epilepsy/Stimulation overload trigger) * Variations * Grow-Shrink (Positive/Negative Winning) mode * Hypnotic / Sleepy mode (Photosensitive epilepsy/Stimulation overload trigger) * Stimulation / Calming mode * Other ideas 5. Scripts * Colours selection * Automate the above gameplay modes 6. Game variables * WAIT - Snake speed * EVADE - Bug evasion frequency * SIZE / MAXSIZE - Initial snake / max sizes * GROW / SHEDS - Growth / Shedding sizes 7. Conclusion (and inspirational words for everyone)

1. Testing terminal environment/capabilities

Most people probably won’t have any issue at all but for those who have any problems with the terminal see the terminals.markdown file for more information on the terminal capabilities testing utility I include.

For troubleshooting other problems see troubleshooting.markdown (troubleshooting.html) and bugs.markdown (bugs.html).

2. Input keys

3. Gameplay

Here I will show the initial screen as well as what a few things look like. If you don’t feel you need this but you want to configure colours jump to colour selection. You can also jump to gameplay modes or game variables.

The bug colour by default is white; the snake head colour is red and the snake body colour is green. The walls are cyan.

Gameplay: The initial screen

When you load the game you will see a screen that looks something like the below. Note that the top line is the score/status line: the top wall is at line 1 and the left wall is column 0. Below I use the coordinates in the X/Y order (ncurses is the opposite: Y/X). I will parenthesise the numbers below to refer to the number in the diagram:

    X:24/49 Y:8/16 S:5/658 B:0
    ##################################################
    #                                                #
    #                                                #
    #                                                #
    #                                                #
    #                                                #
    #                                                #
    #                       +                        #
    #                                                #
    #                                      *         #
    #                                                #
    #                                                #
    #                                                #
    #                                                #
    #                                                #
    ##################################################

Gameplay: Playing the game

    X:39/49 Y:8/16 S:5/658 B:0
    ##################################################
    #                                                #
    #                                                #
    #                                                #
    #                                                #
    #                                                #
    #                                                #
    #                                  oooo>         #
    #                                                #
    #                                      *         #
    #                                                #
    #                                                #
    #                                                #
    #                                                #
    #                                                #
    ##################################################

I let the snake grow to its full size (with the head at (39),(8)) and I’m two places above the bug so let’s go down:

    X:39/49 Y:9/16 S:5/658 B:0
    ##################################################
    #                                                #
    #                                                #
    #                                                #
    #                                                #
    #                                                #
    #                                                #
    #                                   oooo         #
    #                                      v         #
    #                                      *         #
    #                                                #
    #                                                #
    #                                                #
    #                                                #
    #                                                #
    ##################################################

Now you see that the snake is going down and in one move the bug will be eaten. Let’s do that:

    X:36/49 Y:10/16 S:10/658 B:1
    ##################################################
    #                                                #
    #                                                #
    #                                                #
    #                 *                              #
    #                                                #
    #                                                #
    #                                                #
    #                                                #
    #                                   ^  o         #
    #                                   oooo         #
    #                                                #
    #                                                #
    #                                                #
    #                                                #
    ##################################################

Observe that the bug was eaten and a new bug spawned elsewhere. I went left three and then up one and could slither on to the bug.

Gameplay: Walls

By default walls are passable (WALLS=1). Let’s get to full size and go through the top wall:

    X:36/49 Y:15/16 S:10/658 B:1
    ##################################################
    #                                   o            #
    #                                   o            #
    #                                   o            #
    #                 *                 o            #
    #                                   o            #
    #                                   o            #
    #                                   o            #
    #                                   o            #
    #                                   o            #
    #                                                #
    #                                                #
    #                                                #
    #                                                #
    #                                   ^            #
    ##################################################

There you can see I have grown to the full size and went through the top wall; the head is now at the opposite wall. Continuing:

    X:36/49 Y:11/16 S:10/658 B:1
    ##################################################
    #                                   o            #
    #                                   o            #
    #                                   o            #
    #                 *                 o            #
    #                                   o            #
    #                                                #
    #                                                #
    #                                                #
    #                                                #
    #                                   ^            #
    #                                   o            #
    #                                   o            #
    #                                   o            #
    #                                   o            #
    ##################################################

I might then have turned to the left and then shortly go up to get the bug. This goes on until you lose, quit or win the game.

When you specify WALLS=0 the walls become an obstacle that end the game. It might look like (I set the starting size to 150 and had only just started):

    X:20/49 Y:2/16 S:150/658 B:0
    ##################################################
    #                   ^                            #
    #                   o                            #
    #                   o          *                 #
    #                   o                            #
    #                   o                            #
    #                   o                            #
    #                   ooooo                        #
    #                                                #
    #                                                #
    #                                                #
    #                                                #
    #                                                #
    #                                                #
    #                                                #
    ##################################################

If I continue going up I will see:

    OUCH!
    X:20/49 Y:1/16 S:150/658 B:0

Gameplay: Cannibalism

By default cannibalism is disabled (CANNIBAL=0) so if you run into yourself it might look something like:

    X:45/49 Y:10/16 S:10/658 B:1
    ##################################################
    #                                                #
    #                                                #
    #                                                #
    #                 *                              #
    #                                                #
    #                                                #
    #                                                #
    #                                          ooooo #
    #                                            ^ o #
    #                                            ooo #
    #                                                #
    #                                                #
    #                                                #
    #                                                #
    ##################################################

If I were to do any movement but turn to the left I would run into myself. I’ll go to the right two spaces:

    OW!
    X:47/49 Y:10/16 S:10/658 B:1

But CANNIBAL=1 can look very funny both in movement and still especially when you go through yourself several times when the snake is rather long. For example going through walls and the snake a few times:

    X:4/49 Y:12/16 S:165/658 B:3
    ##################################################
    #oo                        o    ooooo  o o      o#
    #                          oooo o      ooo      o#
    #                             ooooooooooooooooooo#
    #                               o                #
    #                 oooooooooo    o                #
    #                 o        o    o                #
    #                 o  oooo  o    o                #
    #                 o  o     o    o                #
    #                 ooooooooooooooo                #
    #                    o     o*                    #
    # oo>                o     o                     #
    # o           oooooooo     o                     #
    #oooooooooooooo            o        oooo oooooooo#
    # o                        o        o  o o       #
    ##################################################

I’ll go back through myself now:

    X:6/49 Y:14/16 S:165/658 B:3
    ##################################################
    #oo                        o    ooooo  o o      o#
    #                          oooo o      ooo      o#
    #                             ooooooooooooooooooo#
    #                               o                #
    #                 oooooooooo    o                #
    #                 o        o    o                #
    #                 o  oooo  o    o                #
    #                 o  o     o    o                #
    #                 ooooooooooooooo                #
    #                    o     o*                    #
    # ooo                o     o                     #
    # oo          oooooooo     o                     #
    #ooooo>oooooooo            o        oooo oooooooo#
    # o                        o        o  o o       #
    ##################################################

If you note that the head is at (6),(14) I will go one more to the right and you will see that the arrow has moved over:

    X:7/49 Y:14/16 S:165/658 B:3
    ##################################################
    #oo                        o    ooooo  o o      o#
    #                          oooo o      ooo      o#
    #                             ooooooooooooooooooo#
    #                               o                #
    #                 oooooooooo    o                #
    #                 o        o    o                #
    #                 o  oooo  o    o                #
    #                 o  o     o    o                #
    #                 ooooooooooooooo                #
    #                    o     o*                    #
    # ooo                o     o                     #
    # oo          oooooooo     o                     #
    #oooooo>ooooooo            o        oooo oooooooo#
    # o                        o        o  o o       #
    ##################################################

Try this: Get a reasonable length and then go back on yourself (if you’re going left go right etc.) and then after some length (but before you get beyond the snake) turn (so that you go perpendicular) and then watch as the snake starts unwinding at one place and then suddenly unwinds another direction.

An example of extreme cannibalism is in the cannibalism.log file. It has more than one run the first of one has several dumps. I didn’t move for a long time: the initial size was 1500 and I would have won before moving if I went after bugs right away. In the last two captures of the first invocation (the third and second to last dump) the bug, head and tail of the snake are at:

     Bug: line 87, col 47
    Head: line 88, col 62; and line 115, col 48
    Tail: line 84, col 46; and line 112, col 29

The final example has the snake inside itself.

Gameplay: Shedding (stretching)

This feature will make you grow by the value of SHEDS for every SHED movements (the counter isn’t incremented when you eat a bug). Basically growing without eating a bug (stretching would be better name here).

Gameplay: Winning

If you ever get to the MAXSIZE the game is won. You can force a win by setting the max size to a smaller value than the size you specify (or the default) or setting the size to higher than the default (or < 0 which will end up being > the max size though I suppose there might be some value that makes it less than again - I’m not going to try and figure that out however). Anyway:

    SIZE=-1 ./prog
    YOU WIN!
    X:24/49 Y:8/16 S:658/658 B:0

Observe that the size isn’t the default 997: because the screen size is too small for that value (see terminals.markdown).

The reason I chose 997 is that it leaves a bit of a challenge for some (maybe most) people but it’s still winnable. Previously even I couldn’t have won unless maybe a much bigger screen, if both cheat modes were disabled. I probably could win without any cheat mode enabled on my 24" monitor but I probably would need at least one cheat mode on my 13" laptop (I don’t need both enabled).

The beauty though is the game can be winnable by anyone since you can define the max size to win. Games are meant to be fun: who enjoys games that can never be won? Very few probably do and those who do enjoy them it probably are games that are relaxing and stimulating (which admittedly this game can be - but still I want it to be winnable too).

Another reason I chose 997: it’s prime and the judges love prime numbers. Actually, this is the main reason for the number: I had changed it down to 1000 but then it occurred to me that there are prime numbers close to 1000 so why not choose one instead (that was less than 1000)? And so I did. Another fun fact: at the default starting size and growth size of 5 the number of bugs needed before the game is won is 199 - also a prime!

Gameplay: Quitting

If you wish to quit you can hit ‘q’ (case-insensitive). For example:

    X:24/49 Y:8/16 S:5/658 B:0

4. Gameplay modes

Here I list a number of different modes of play. In the bugs.markdown (bugs.html) file I even show how there’s a built-in test unit for some modes! There are certainly other modes that could be imagined: the modes below happened over time and some were simply an accidental discovery or something I thought of by a chance; others were thought out from the beginning but were improved over time.

The play.sh script sets up some of these automatically; I describe it after the modes below.

Photosensitive epilepsy/Stimulation overload trigger warnings

If you have photosensitive epilepsy please be careful especially with low values for both WAIT and EVADE. It appears that the number of hertz (flashes) per second triggering seizures is wide but depending on the variables it easily can be in the range.

There are different patterns and lights flashing at different speeds so please exercise caution. This could trigger seizures and it might also be too much stimulation for some people.

Please be careful of these if these types of things have ever affected you or if you have any form of epilepsy. Thank you.

Gameplay mode: Drawing / Practice mode

If you want to draw the snake wherever you like on the screen you can do this by modifying the wait time (for input) to -1 (or any value < 0): then the snake does not move until you press a movement key. For example:

    WAIT=-1 ./prog

When you eat a bug the snake will grow and you can draw more. If you want to make it so you can go through yourself:

    WAIT=-1 CANNIBAL=1 ./prog

If you don’t want to start out so small (i.e. you want to be able to draw more quickly) you can just set the size to a bigger number (and you could do the same with growth and moult/shed):

    SIZE=50 CANNIBAL=1 WAIT=-1 ./prog

Do note that although you’re a bigger size you still grow one movement at a time.

Okay but then if you get too many bugs the drawing will be over. If this proves to be a problem simply do:

    SIZE=100 CANNIBAL=1 WAIT=-1 GROW=0 ./prog

Or something like that (maybe make the size bigger but that’s up to you). You could also set the max size to be the highest possible by saying

    MAXSIZE=-1

Which I’ve done in the play.sh script.

I discuss how this mode works in spoilers.markdown.

Here’s an example run where I spelt ‘SNAKE’. As you can see it’s far from perfect: the snake after all does not leave gaps and the game does not support diagonal movement and I also made a mistake and had to modify what I was aiming for. But you can consider this mode drawing or practice mode.

       oooooooooo   ooooo    o  oo  ooooo
       o     o  oo  o   oo   o ooo  o    
       oooo  o   oo ooooooo  oooo   ooooo
      o  o    ooo     oo o ooo  o    
       oooo  o     oo      ooo  oooooooo>

Gameplay mode: Computer playing / Automatic mode (Photosensitive epilepsy/Stimulation overload trigger)

Photosensitive epilepsy/stimulation overload trigger warning: For those who have epilepsy or are susceptible to stimulation overload from flashing lights please do be careful with this mode. Depending on your susceptibility this could very well trigger seizures or other discomforts and I wouldn’t want that to happen to anyone. This mode has a lot of flashing of different colours and depending on the exact parameters you specify it could easily be in the trigger range for epilepsy but potentially stimulation overload too.

If you’re still here you can create this effect like:

    WAIT=0 WALLS=1 CANNIBAL=1 ./prog

As long as the bug evades you’ll find that the snake is growing because it’s actually eating bugs; the computer is actually playing the game by itself! You can still move the snake though it won’t seem like you have much control over it. If you pause the game you can see that it’s bigger (you probably will be able to even without pausing it).

Basically the snake is moving so fast that because the bug evades the bug will inevitably move in the snake path’s and therefore be eaten.

You might find it goes quicker if you set the evade count to a lower value for example 1. Or you might not. But as long as the bug moves the computer can play by itself.

Quick tests suggest that bigger dimensions it gets bigger quicker. But it also seems to take longer for it to get a bug as it gets longer. I believe these happen because the bug has to find a X and Y coordinate that’s not occupied and so with fewer available it has a harder time finding a place in that one line.

Computer player variations

Here’s how to make the bug move every time the snake moves:

    CANNIBAL=1 WALLS=1 WAIT=0 EVADE=1 ./prog

Help the computer win fairly quickly

If you want to see the game ‘win’ try something like:

    CANNIBAL=1 WALLS=1 WAIT=0 EVADE=1 MAXSIZE=10 ./prog

Negative growth (Shrink) Automatic mode

Here’s a fun one I just thought of (a long time after these other modes were thought of):

    WAIT=0 EVADE=1 GROW=-1 SIZE=9 MAXSIZE=10 CANNIBAL=1 ./prog

What you’ll see is that first the snake will get to the size of 9 - whether it shows to be 10 characters depends on whether or not it gets a bug before it can get to that length - and then it’ll start shrinking until it’s just the head then the head again (i.e. 1 then 0 in size) and then win! This is also in the play.sh script.

Adjusting the time/speed

Of course you can also do something like:

    WAIT=5 WALLS=1 CANNIBAL=1 ./prog

Which although might not seem like it is significantly slower.

Moving the snake about to create patterns

If you press different direction keys in some pattern you will see a pattern form too (entirely dependent on how fast you react, what keys you press and I suppose also how much the bug moves and the chance of being eaten also).

Other ideas

Here’s an idea: how many moves is needed to make it possible to have some sort of success in catching bugs? Obviously the dimensions will affect this value.

How long will it take for the snake to run into itself? For instance by doing:

    WAIT=0 ./prog

On my 13" MacBook Pro at the default settings going horizontally the snake ran into itself at:

    OW!
    X:57/156 Y:20/41 S:155/997 B:30

What if you set the size to a high value? The lowest? There are bound to be other games to play with this feature!

Gameplay mode: Grow-Shrink mode (Positive and Negative Winning)

In this mode you’re simultaneously growing and shrinking but because the max size is unsigned you can win both by shrinking to the point of losing your body or growing to the full size directly. This is how it works:

You have a negative shedding growth and a positive growth size: negative and positive winning. Depending on the parameters specified it might go one way over the other. Try:

    SIZE=150 SHEDS=-5 GROW=10 SHED=50 MAXSIZE=250 ./prog

What this does is set the size to 150 (to make it not go down so quickly) and then for each bug you eat it adds 5 to the size; for every 50 moves (that you don’t get the bug) you shrink by 5. You will find that at times you might only decrease in size but then at other times - depending on size of screen and how lucky you are with where the bug is relative to where it last was - you might be growing. Combining this with the drawing mode could be interesting but I never actually tried it.

The parameters above were chosen after playing with the mode a bit to find a value that wouldn’t take that much time but still would pose a challenge. One could reverse it so that one shrinks more than growing.

The crazy.log file has several screen dumps with this idea.

You could also have it so that eating a bug makes you shrink and moving so many moves you grow. I tried this and for me it was far more fun. The play.sh also has this mode:

    SIZE=100 SHEDS=5 GROW=-10 SHED=50 MAXSIZE=250 ./prog

Obviously there are many other variations. The play.sh script has some of them (the above is option 5; others are 4, 15 and 16 but only options 4 and 5 are called Grow / Shrink).

Hypnotic / Sleepy mode (Photosensitive epilepsy/Stimulation overload trigger)

Photosensitive epilepsy/stimulation overload trigger warning: For those who have epilepsy or are susceptible to stimulation overload from flashing lights and patterns please do be careful with this mode. Depending on your susceptibility this could very well trigger seizures or other discomforts and I wouldn’t want that to happen to anyone. The default wait time is 231ms, the typical range of seizures is 3 to 30 flashes per seconds (but can be higher) and that means that at EVADE=1 every 231ms there will be a flash in addition to the snake moving too.

Anyway this might sound absurd but it can be somewhat hypnotic by doing:

    EVADE=1 CANNIBAL=1 ./prog

And just moving the snake about not trying to catch any bugs - just let whatever happens happen.

Gameplay mode: Stimulation / Calming mode

If you just need something to stimulate your mind to keep you calm or simply you want to play a game without having to worry about winning or losing you can set the growth size to 0 and then just move the snake round and round eating bugs until you want to quit. You can enable cannibalism so that you don’t have to worry about even running into yourself and losing:

    GROW=0 CANNIBAL=1 ./prog

Gameplay mode: Expansibility

As I was writing this document and the game modes I have thought of other game modes (they were added) and I have come back to this document to add more modes. That’s the beauty of the variables I have implemented: together with the imagination and even just chance different modes of play can be devised. The drawing mode was a happy chance of how the timeout() function works for example.

As a person who was heavily involved in MUD development and design I know very well how games need to be fun and have different options, not be too easy but not be too hard either. And a game developer who does not play their games is a game developer who is detached from their player base and the wants and needs are therefore disregarded if even heard. I have played this game a lot for this reason as well as I simply enjoy it and thinking up new modes.

5. Scripts

The following scripts are provided to simplify and automate some of the things this file discusses as well as allowing to easily change the colours.

Colours selection: snake-colours

To do this use the snake-colours script like so:

    ./snake-colours

If you want to pass in specific variables you can do that too e.g.:

    CANNIBAL=1 ./snake-colours

The script will prompt you for the colour of the walls, snake head, body and the bug.

Automate the above gameplay modes

The play.sh script has the gameplay modes described in this file and is menu based (there might be differences and some of the modes I include a variation). The script tests the terminal (allowing you to continue even if problems are detected), prompts you if you want to select colours (like those in snake-colours above) and then gives you a list of game modes to play. You can pass in the game variables but note that if you pass in a variable that the mode you choose uses then the script will override what you pass in.

To use you can do something like:

    ./play.sh

Or to make it so walls are an obstacle:

    WALLS=0 ./play.sh

6. Game variables

The game variables can be used for a variety of things including different gameplay modes as above but here are some notes about a few of them.

WAIT: Snake speed

Besides the different game modes if you find it too fast/slow you can change it to a value that’s better for you. Remember it’s a wait time so if you want the snake to move slower you have to increase the wait time!

EVADE: Bug evasion frequency

For every EVADE snake movements the bug will try and find a new place to occupy. It might be very close to it and I do not ensure it’s a new place at all.

Each time the bug is placed the counter will be reset whether from eating the bug or not reaching it in time. Default 300 moves.

This can help you get out of a trap but it can also sometimes make it harder.

SIZE / MAXSIZE: Initial / Max snake sizes

997 might be a bit high for many people. Or maybe you don’t have enough time. Or you’re not in the mood to lose. Or you want to get close to a size you were last time but quickly. It might be in conjunction with drawing mode.

Note on snake size: there’s a stated size (in the score line) which is what the snake will ‘populate’ in the snake arrays and the visible size: as I have discussed here and there the snake doesn’t grow immediately so it takes time before the snake is visibly that many characters. In other words just because it says SIZE 29 doesn’t mean it will instantly be 29 characters on the screen.

GROW / SHEDS : Growth / Shedding sizes

Similar to the initial size. Notice that the above point on size applies here: it will take the number of movements before it is ‘its full size’.

7. Conclusion (and inspirational words for everyone)

I believe that this file has given more than enough information for anyone to get an idea of what is possible with my implementation of Snake. I realise also that most people won’t have read this far and that’s quite all right; I’m very thorough and pay attention to details obsessively. Creating this game was a delight and I am quite proud of what I have done.

Thank you for whatever level of attention you felt you could or wanted to give and enjoy it in whatever way you see fit!

Much more importantly is that Snake aside I hope I have demonstrated how with the imagination and creativity almost anything is possible. This is something that applies in our world in every way and everyone can do something amazing if they believe in themselves! I would have never thought this the case for me years ago but I know it’s true now. Believe in yourself. Always.



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