I know this is a pretty open question but I was wondering how people go about writing scripts that will "play" a game, or manipulate it in some way. I had been thinking that I'd try to get a working AI to play a game for fun, but don't even really know where to start. Are there any good resources to learn this? What are good languages to use? Once I have the language, how do I get my script hooked into the game? I was thinking of just trying simple flash games, if that helps.
Thanks a bunch!
Are you looking to "play" an existing game, or write some sort of a game that can then be scripted?
If the former, you find that game's API and start writing code in the appropriate language. E.g. Unreal-powered games use UnrealScript and ship with the tools so you can embed new functionality. You're pretty much dependent on the game creators leaving an "in" such as this...
...unless you want to get totally nutty and hack the executable itself to execute your own code somehow. For information on how to do this, search for information on game "trainers". I'm not sure what a great set of search terms would be, but I know a lot of games do have trainers released, so type in "trainer <my_favorite_game>" and see what you get?
You can do this quite simply in Java 6.
expose your objects/functions in your Java app into the scripting environment
For example you can expose your character or the game world into the scripting environment and allow the script to control it.
invoke script functions/methods from Java environment
Allow the script to customize behaviours, add new actions, etc. Another use of this is to override the default build in game rules and load your own house rules. Another use is as a macro facility. Typically this would be part of the main game loop
use the script as a data/level file
For example, in a game likes SpaceHulk where it is mission based, you can use a script to define a game specific DSL, and us this DSL to define new missions. When the game starts up, it evaluates the data file and create a model of the game.
To integrate a scripting engine into Java, simply do this
ScriptEngineManager mgr = new ScriptEngineManager();
ScriptEngine jsEngine = mgr.getEngineByExtension("js");
jsEngine.eval("print('Hello world!');
To expose an object into the script environment
jsEngine.put("avatar", avatarObject);
//An avatar object is now available in myscript.js
jsEngine.eval(new FileReader("myscript.js");
To invoke a function in the script
jsEngine.eval("function hello(name) ... ");
Invocable inv = (Invocable)jsEngine;
inv.invokeFunction("hello", "Fred");
One of the problem with scripting is that, the script has access to your entire application. You can restrict what the script can 'see' by setting a classloader when you create the ScriptEngineManager instance.
Java 6 comes with a bundled JavaScript engine. However I prefer Groovy and loading Groovy basically mean changing 'js' in getEngineByExtension() to 'groovy'.
I know that a lot of people say that Java is not fast for games, but if you are writing turn based games or social games like Farmville then I think it is more than adequate.
For C/C++ based games, I think the preferred script engine is Lua. I've not used it so I cannot comment on it.
The best way to do that is to use the API provided by the game, if there is one. The Civilization games, for example, come with a very complete modding engine that allows you to script whatever you want. The same can be said for Age of Empires and a variety of other games.
Simple flash games, though? That'll be tough. Those don't generally provide any supported way to script, so you'll be left with simulating input. It'll be tough.
The easy way is to control mouse and keyboard functions with autoit. You can also read out information from your screen, but it is a bit limited It is good to just check if things changed or check whats on a certain area of the screen if you know there are a limited amount of possibilities. Not so easy to read and interpret text. Autoit is excelent to automate games like farmvile. I have also made blackjack bots for online casinos. And use it for small but mundane and repeating (manufacturing) tasks in RPGs. Dont expect to build an AI for an RTS or FPS though.
Autoit is easy to find with google. A fast and small download. Excelent documentation and you can learn it in days.
The hard way is what people wrote about above here i guess. Interacting with the game data. Searching information on that is what brought me here. I see its with C++ or Java. While the languages are all similar and you can use them all after learning 1, these come with complicated software environments that take lots of time to learn. The possibilities and chances to make something really reliable are much much greater though.
Related
Can someone guide me as googling does not send me to the right places.
I want to adapt netlogo to include players real or simulated with other technologies. I need to interface the netlogo core (running an established game) and have the moves and choices determined by the external entities, which may be human or automania.
In searching for the API to allow this, I can find is the controlling API which is seems to be for running NetLogo muitiple runs of a model and not what I want.
And please before you close this again suggest how I can make this more focused as the problem is finding the starting point....
Can anyone assist.
Regards
Robert
There are two main ways to interface between NetLogo and the "outside world":
The extensions API.
The controlling API.
Which one to use depends on what you're trying to achieve.
You say that you:
need to interface the netlogo core (running an established game) and have the moves and choices determined by the external entities, which may be human or automania.
That, to me, sounds very much like a job for the extensions API, which is what has been suggested to you on the netlogo-devel group. Extensions allow to add new "primitives" to NetLogo, and those primitives can be written in any language that runs on the JVM (Java, Scala, Clojure, etc.)
So if you have a game written in NetLogo and a bot written in some other language that the JVM can interface with (possibly by using the JNI), you could write a new NetLogo extension command that calls out to the bot (e.g., something like bot:play game-state). A game written in NetLogo could then use that command to let the bot play its turn.
If that is indeed what you want to do, then Jeremy has already given you a good starting point in his netlogo-devel answer, and there is not much we can add to this until you have more specific questions.
You also said, however, that you looked at using the controlling API, so maybe what you had in mind is to have a game written in some other language, and use a NetLogo model to generate the behaviour of a particular player in that game. The controlling API allows you to do that. (It's not just for running a model multiple times!) If you look at the examples in the controlling guide, you'll see that you can use the API to send commands to a NetLogo model and to report the results back to your external program. The only constraint is that this external program needs to be able to talk to the JVM.
If you don't think this answers you question, please try to give us a concrete example of a precise thing that you want to do but do not think can be achieve in one of these two ways. We might be able to help you better than.
Why Neto/Shopify use their own templating language instead using any popular popular language ?
When you have your own templating language you have full freedom to implement or limit the logic of the language to meet your needs.
You don't need to wait for a third party update in order to implement new stuff or objects.
Why do you think Samsung creates clones of google apps on their phones? To create an experience that they can control in some way and if they like to change or add something to do so and not to wait for google to do so. ( and some other things but that is outside the scope of this question )
Since liquid was a Tobias Lütke creation ( co-founder and CEO at Shopify ) and now is an Open Source project it was written in specific fashion in order to meet specific needs and those needs seems to be fitting for Shopify and other platforms as well.
Being popular doesn't mean being better! This is the wrong way to go.
WordPress is the most popular platform, but is it the best one - NO! There are a lot of hole provided by plugins, poorly written themes and some times core issues. While it's easy to use and extendable it opens a lot of doors for issues if you don't manage it properly.
Beats by Dre is the most popular headphones and quite expensive, does they sound as good as the price tag put on them - NO! You can buy the same quality headphones ( even better ) for less, but you are paying for the brand.
Creating new languages in the coding world is ALWAYS a good thing It might be a chore to learn it if it becomes a standard but that means that it provided something that the other popular languages didn't and this pushes the coding world forward. It's a much better alternative than to be in a standstill like when we had only jQuery and there were no new stuffs to excite the developers.
Now we have so much different things that you can choose the direction you like to go and you won't be able to learn all of them even if you try, which is a great thing to a developer who likes to grow.
Conclusion:
Being different is OK as long as that fits your needs and you are not doing it just because it's popular to be different. ( so true IRL now too :D )
This reasoning from their Github Wiki lists some of the reasons. Why Liquid Templating Engine ?
Liquid is a template engine which was crafted for very specific
requirements
It has to have simple markup and beautiful results. Template engines which don't produce good looking results are no fun to use.
It needs to be non-evaling and secure. Liquid templates are made so that users can edit them. You don't want your server running code
that your users wrote.
It has to be stateless. The compile and render steps have to be separate, so that the expensive parsing and compiling can be done
once; later on, you can just render it by passing in a hash with local
variables and objects.
It needs to be able to style emails as well as HTML.
I need a 3D engine for a very specific task in Artificial Intelligence, and I'd like some input.
The first part is the trivial one - basically, all I need is a FPS engine (3rd person would be good, too), such that it allows me to navigate a room and interact with objects (if you have Java and Windows, I'm looking for something similar to the Give Challenge, but a little more up-to-date). Physics would be nice, but is not a must.
Now, the non-trivial part would be: I need to impose a virtual grid over this room, such that at any moment I can say "the player is located at B5 - now he moved to B6", and so on. I need to redirect this information to another system (namely, one which will give the player instructions about what to do) and, at the same time, send messages to the player, so I must be able to have a single point through which the game logic passes through; also, I'd love not having to write my own collision detection and such.
So far, I've tried:
the Source SDK: it seems a little overkill (since I'm not really planning to shoot anyone, at least half the code base is useless to the task), and since I'm not really a Windows developer, I'm spending too much time with the "easy" stuff (such as getting VS up and running). Plus, cross-platform would be really nice.
Blender game engine: while this worked decently, the interaction model seems a little weird, and some easy stuff (such as making sure the camera stays inside the scene or showing the mouse on screen) gets too weird too soon.
Crystalspace 3D: I've tried their demos, but it looks a little old-fashioned, and since that was one of the problems of previous engines (it's easier to get volunteers when your game looks nice) I'd like to try something else.
Now, maybe I'm asking a little too much for a single software, but I'd love some input. Can anyone suggest me an alternative? Or should I give one of the previous ones a second chance?
Try the UDK. All of the things you request are present, and it's free for personal/noncommercial projects. Here are some highlights:
Modern looking. The UDK features an intuitive-ish visual material design system, post-processing effects, Scaleform Gfx UIs from Autodesk, and more.
A visual scripting interface called Kismet that can control gameplay elements, the camera, and more.
UnrealScript, a scripting language similar in syntax to C, C++, Java, that gives you the ability to extend existing functionality or create your own.
Comprehensive documentation available on UDN.
Lots of community support outside of Epic, in places such as Polycount, Eat3d, 3dbuzz, and more.
Basically, "and more".
If what you're looking for is a professional, free (as in beer) engine that will allow you to focus primarily or solely on your differentiating gameplay features, Epic has set the bar high.
I've started helping with an open source game (based on Cocoa, Obejctive-C, Xcode). The existing game engine is already setup to allow the character to run around the world, encounter an enemy, and when combat is begun, a characterObject is called with the enemy unit object that is to be attacked. This characterObject has a default method of attacking the enemy.
I wanted to improve on this design by extending the program to allow others to develop a combatUnit plugin that would handle the combat actions in their own programmed way. This could open up the community to develop different styles of combat and come up with their own unique play style.
As I began to look into Plug-Ins and examples on how to build, most of the examples kept the plug-in relatively isolated from the internals of the rest of the program. And any data the plugin required would be passed into the routine(s) themselves.
However, in this case, a combat unit developer might want to have access to numerous external objects in the existing game: a developer might want to also know of any nearby enemy units to avoid any potential adds in a fight and would have to access several of the existing environment objects to get that data, the character might be in a group and the developer might want access to the group info and each players data to determine if they should heal, etc... Not knowing what a developer has in mind, it would be unfeasible for me to attempt to predict and pass in all potential info for them to use.
So, my question is:
Is this a good application for a Plug-In? If so, when developing the plug-in how do I open up the other objects for the plug-in developer to code against?
Is there another approach to solve this problem? Something else than a "Plug-in" that would be more appropriate for the code to have access to the game's objects?
Thanks for you help!
That’s a good case for making plug-ins. As an alternative you could compile the new objects directly into the game or use a scripting language interpreter. But with those you’d have to solve the same problems of how to give access to the internals of the game to the new combat unit.
The cleanest way to do this would be to define an interface to the game (either as a protocol or a base class) and pass that to the plug-in. Using this object the plug-in can then query anything it needs.
I'm playing WoW for about 2 years and I was quite curious about Lua which is used to write addons. Since what I've read so far about Lua was "fast", "light" and "this is great", I was wondering how and when to use it.
What is the typical situation where you will need to embed a script language like Lua in a system ?
When you need end users to be able to define/change the system without requiring the system to rewritten. It's used in games to allow extensions or to allow the main game engine to remain unchanged, while allow content to be changed.
Embedded scripting languages work well for storing configuration information as well. Last I checked, the Mozilla family all use JavaScript for their config information.
Next up, they are great for developing plugins. You can create a custom API to expose to the plugin developers, and the plugin developers gain a lot of freedom from having an entire language to work with.
Another is when flat files aren't expressive enough. If you want to write data driven apps where behavior is parameterized, you'll get really tired of long strings of conditionals testing for config combinations. When this happens, you're better off writing the rules AND their evaluation into your config.
This topic gets some coverage in the book Pragramtic Programmer.
Lua is:
Lightweight
Easy to integrate, even in an asynchronized environment such as a game
Easy to learn for non-programmer staff such as integrators, designers and artists
Since games usually require all those qualities, Lua is mostly used there. Other sitation could be any application that needs some scripting functionality, but developers often opt for a little more heavy weight solution such as .Net or python.
In addition to the scripting and configurability cases mentioned, I would simply state that Lua+C (or Lua+C++) is a perfect match for any software development. It allows one to make an engine/usage interface where engine is done in C/C++ and the behaviour or customization done in Lua.
OS X Cocoa has Objective-C (C and Smalltalk amalgam, where language changes by the line). I find Lua+C similar, only the language changes by a source file, which to me is a better abstraction.
The reasons why you would not want to use Lua are also noteworthy. Because it hardly has a good debugger. Then again, people hardly seem to need one either. :)
a scripting language like Lua can also be used if you have to change code (with immediate effect) while the application is running. one may not see this in wow, because as far as i remember the code is loaded at the start (and not rechecked and reloaded while running).
but think of another example: webserver and scripting language - (thankfully) you can change your php code without having to recompile apache or restart apache.
steve yegge did that thing for his own mmorpg engine powering wyvern, using jython or rhino and javascript (can't remember). he wrote the core engine in java, but the program logic in python/javascript.
the effect of this is:
he doesn't have to restart the core engine when changing the scripts, because that would disconnect all the players
he can let others do the simpler programming like defining new items and monsters without exposing all the critical code to them
sandboxing: if an error happens inside the script, you may be able to handle it gracefully without endangering the surrounding application
Rapid development for application with real-time constraints. Computer games are one of these ;-)
It's a valid solution if you want to allow third parties to develop plug-ins or mods for your software.
You could implement an API in whatever language you are using, but a script language like LUA tends to be more simple and accessible for casual developers.
In addition to all the excellent reasons mentioned by others, Embedding Lua in C is very helpful when you need to manipulate text, work with files, or just need a higher level language. Lua has lots of nifty feature (Tables, functions are first class values, lots of other good stuff). Also, while lua isn't as fast as C or C++, it's pretty quick for an interpreted language.