An Introduction To Terrarium

1. An Introduction To Terrarium An Ex-Student’s Perspective

2. Terrarium – The Basics • Real-time ‘game’ of imperfect information • You control a ‘bug’ that lives within a ‘Terrarium’ • Current information about the environment is restricted to the area immediately around and in front of your bug • Lots of bugs can inhabit the same Terrarium at once

3. Virus vs. Terrarium

4. Virus vs. Terrarium continued… • Those who found Virus’ evaluation function based approach confusing or counter-intuitive may find Terrarium’s rule based approach easier to use • If two Virus players didn’t use random numbers at all they would always play the same game – deterministic • If two Terrarium players don’t use random numbers at all there are still random elements outside of their control – non-deterministic • Less tuning and optimisation of variables • More strategy and planning – more scope for creativity (but only in my opinion!) • I personally enjoyed Terrarium more than Virus

5. What’s a Terrarium? • An area surrounded by obstacles within which bugs can move and perform actions • Terrarium Academic includes bugs, rocks (obstacles), plants and goals • Objects are solid • Objects have different sizes

7. Terrarium Bugs • Bugs are introduced into a Terrarium and perform actions based upon their code • Code (should be!) arranged so that the bug reacts to its surroundings • A set of pre-defined methods and variables are available to write bug code • API should be helpful and easy-to-use • Tool-tip text for all applicable methods and variables

8. Bugs continued… • Your bug (and all bugs) have certain attributes you can access, e.g. • Health (Vital!) • Score (Important!) • Position • Speed • Direction • Kills • And others…

9. Ticks And DoAction() • A game of Terrarium takes place in real-time, but is still divided into turns • A turn is referred to within Terrarium as a ‘tick’ • Each game is comprised of many ticks • Every tick, each bug’s DoAction() method is called • This method is where you write you code • It tells your bug what to do for the next tick • Where to move, what to eat, what to attack etc.

10. Ticks And DoAction() continued… • Within your DoAction() function you must write code that looks at what’s going on around your bug and what condition your bug is in, then makes a choice about what to do next • Your method is called; within it you call other methods that will make your bug perform actions like eating and fighting • You can write your own methods to call from DoAction(), and you can use several built-in ones • Make choices based on the environment and the variables that describe your bugs current condition

11. What’s the Point? • The aim in Terrarium (the game not the coursework!) is to get a higher score than all the other bugs in the Terrarium • Score points in two ways • Kill opponents • Collect points from ‘Goals’ • Goals can be hard to reach, difficult to find or in dangerous locations! • Other bugs probably aren’t going to just roll over and die!

12. Points from Goals • Goals have a fixed payout • When a bug collects the points from a goal, it turns red (inactive) for an amount of time • Fixed Time • Random Time • Points

13. Points From Bugs • Killing a bug by reducing its health to zero results in you getting half of its points • Killing blow is the only one that counts! • High-scoring enemies vs. low scoring enemies • Balance and compromise

14. Staying Alive • Health is reduced through combat • When you get attacked health decreases by a random amount – find out how much yourself! • Defending can reduce the damage taken in combat • But! Can only defend against one bug at a time! • Counter attack – fighting back • Again, can only attack one bug at a time • Can both defend and attack simultaneously

15. Staying Alive continued… • If victorious in combat you’re still likely to be injured • Health does not regenerate naturally • Have to eat! • Plants and dead bugs are both sources of food • How much is healed per unit of time is again left to you to discover (I’m still not sure!)

16. Staying Alive continued… • Plants are static • If you saw it once, it’ll still be there next time! • When close to a plant you can order your bug to ‘eat’ it • Your bug will recover some health • The plant never dies and is never ‘eaten up’ • Plants are also always ‘active’ – unlike goals that need time to ‘recharge’ before they give points out again

17. Staying Alive continued… • Clever strategies for combat are helpful and encouraged • Sneaking up on opponents • Lying in wait • ‘Camping’ at good spots • Preying on the weak (mean but effective) • Avoiding combat entirely • And many, many more…

18. Ticks And DoAction() Again • Very simple example: • Your bug is injured and there are no other bugs around • A plant is nearby and is in a quiet and safe position • Probably a good idea to go and eat it! • Call method to move towards plant • On each subsequent turn, check if you’re close enough to eat it • If so, start eating it!

19. Ticks And DoAction() Again • More complicated example: • Your bug is moderately damaged and there are no bugs in the immediate area • There’s a plant nearby that is very exposed • Another plant is further away but safer • This Terrarium has been running for nearly the entire pre-set time limit and your score is quite low • Heal? Score points? Fight? Run away? Spin around and around for the remaining time? • Up to you!

20. Interacting With The Environment • How do I do all these wonderful things? • Environment is only accessible locally i.e. I can see (or ‘feel’) anything my bug is touching and anything in a small-ish arc directly in front of me • However, information about what I’ve seen before can be collected and stored for later use

21. Stored Information About The Environment • Arguably the most important – a list of all the goals seen to date • Information about their location, the points they offer, their fixed and random times are all stored and can be accessed at any time • Details of how the information is stored and how to access it will be discussed in subsequent lectures – same goes for plants and bug information

22. Stored Information continued… • A list of all plants and their information is stored also • Information about their location is generally the only relevant thing you’ll use • Again, information can be accessed at any time • Most likely to use it when your injured and looking for a place to heal

23. Stored Information continued… • Information about bugs is also stored • Lots of information is recorded about bugs • Health, score, kills, speed, heading, position etc… • When you last saw them (important!) • Only have information about bugs you’ve seen • Bugs (unlike goals and plants) are dynamic • Probably not going to be in the same place or have the same information as the last time you saw them • As the information gets more and more out of date, it’s likely to become less and less reliable

24. Stored Information continued… • Aside from information about the goals, plants and bugs within the Terrarium, another extremely helpful feature is the Map • A record of the whole Terrarium, which starts blank but is updated as you explore • Arranged internally in a natural way that corresponds to the actual layout of the Terrarium • Can be accessed at any time and for any position in the Terrarium

25. More About Mapping • Terrarium uses a positional system similar to Cartesian co-ordinates • GridX and GridY • X and Y co-ordinates like a graph • Different origin • All bugs, plants, goals and rocks have a position specified by a GridX and a GridY • Different objects have different sizes!

26. Mapping continued… • The map is arranged identically to the Terrarium co-ordinate system • The specific details of how to use and access it will be covered later • Simple 2-dimensional array arrangement • Contains information about what is in the square • If it’s an organism (goal, rock etc.) it also stores information about the organism

27. Bug Vision Basics • As mentioned, bugs can ‘see’ and ‘feel’ objects that are either touching them or are within a 120° arc directly in front of them • Arc extends for just under two bug lengths (roughly 8(?) GridSquares) • Information about goals, bugs etc. is automatically updated every turn • But only information about things you can currently see are updated! • Beware of out-of-date information

28. Vision And Exploration • New feature for this year • Have I seen this square? • Map holds a boolean (true or false) variable for every square in the Terrarium that is true if your bug has seen the square, and false if it hasn’t seen the square • Handy for exploration • How to use it is again left to you

29. Moving Around a Terrarium • Moving can occur in one of two ways • Move to a position in a straight line • Position can be specified exactly, or can be supplied by saying ‘move to this goal’, or ‘move to this plant’ etc. • Find a path and move along it • Obstacles almost always disrupt movement in a straight line • Automatic path-finding and following code

30. Path-Finding continued… • Based on the A* Algorithm • Specifics on path-finding and the methods used within Terrarium will again be covered later • Fairly efficient method of path-finding • Really shouldn’t call it many times within a single DoAction() • Fairly relaxed time-limit on thinking (but one exists nonetheless)

31. Path-Finding continued… • As you’ll see the path-following code is not perfect! • Works well enough to allow you to plan and make journeys over long distances • Breaks journey down into smaller, straight line segments automatically • Don’t worry about understanding how path-finding works at this stage

32. Enough On The Basics! • That concludes the basics of Terrarium • Almost certainly left something out though! • Don’t worry, any omissions or confusing points will be explained in later lectures! • Any questions at this point?

33. Basic Strategies • Ideas to use in Terrarium can come from a huge variety of places • Articles online (and on the module page) • Journals and books from the library • AI – techniques and approaches • Nature – what real bugs do • Web-sites • From nowhere! (Original ideas)

34. Strategy • As well as short term plans (heal when I’m hurt, attack a weak and nearby bug) you will probably also want to have a long term strategy • Explore everywhere • Kill everyone • Hide for a long time till everyone is dead • Etc…

35. Strategy continued… • Rewarded for original, interesting and unique ideas • Like Virus, it helps a lot if they actually work! • The point of the game is to score the most points • The point of the coursework is to be creative in the way you try to score points!