Arcade Fighting Game AI - finite-automata

I need to build the AI for an opponent in an arcade style fighting game, very similar to Mortal Kombat.
I don't want to use random moves for the computer, but I would like to have an AI that is harder to beat.
Where can I start looking for resources ? Do you know of any implementation of this sort of project ?

Think about how you play the game.
Ask yourself, under what conditions would I perform certain attacks? When would I block? What do I do when I have low health? When my opponent has low health? Do I become more agressive in one situation over the other? When is it best to use long range versus short range?
Etc.
An AI like this usually only follows a bunch of if/else/then statements, with som randomness added in.
You want it to react quickly so much of anything else (A*, alpha-beta, etc) won't be as useful.

There is an algorithm which depends on statistic and count of shoots in each direction. You can put such logic to calculate how many times enemy kicked you in needed direction and predict future attacks.

Related

Is there any tool for defining roles and relationship of game dynamics

We want to develop a game for multi user can play at the same time with together in browser. This game will be text-based. It has a strong scenario. But some roles,skills,experience etc. are not clear.
We are searching a tool to manage and defining roles and dynamics of the game. Do you know any tool like this.
There is no such "tool" to magically manage the balance of different character classes in any game, if that's what you're looking for. You'll have to make your game and test it, a lot.
If you have say, stats such as strength, critical chance, evasion chance, precision, attack speed, etc., then it's relatively simple to make a simulation where you just specify two characters and let them fight against each other.
But this question is overall way too generic for a precise answer and is poorly tagged. And I wouldn't recommend using Game Maker for a text-based game.

Create winnable "random" solitaire shuffles

I've created a solitaire game for Mac, but people keep complaining that there's not enough "winning" shuffles. People have a win-rate of about 5%-10%, where their usual win-rate is around 50%.
Right now, I'm creating an array with all the cards in the deck and after that I shuffle that array, using the F/Y method.
So my question is... is there any way that I can "check" for a winning solitaire shuffle, so I can bump up the numbers of winning solitaire shuffles I'm dealing to people?
Do you have a backend part of your app? if so then you can store all success (win) shuffled arrays on the server from all the users and increase the win-rate by sending them successes from other users with some frequency.
I read that for some sort of these games, there is no more efficient way than to do brute force checking of all possible moves.
My suggestion for situations like this is to start from the completed state (end of game), and move backwards randomly to create a random start state.
I run site with thousands of solitaire games played a day. We tried to built an AI that would allow us to understand what hands were winnable or not. It turns out, like many of the responses, that there are so many permutations to win or lose a solitaire game that an AI to detect a winnable or non-winnable game is extremely difficult to build and requires significant processing power. We weren't able to succeed in building it.
Now, we simply leverage our user data to find which games are winnable, and offer that as option for players who want to play winnable only games. Otherwise, they can choose a random game. I would recommend trying something similar!

any path-finding tricks and strategies for mobile game (e.g rts) on less powerful device?

i'm developing a 2d game , rts game, is sort of like COC (Clash of Clans). cool mobile game,huh. but i run into some problem with path-finding, as usual,i do path-finding algorithm once every agent was placed somewhere in screen by finger-touch,but in some case, this incur performance penalty, and your mobile phone will be very hot as your agents increase suddenly and simultaneously.
actually,no matter what path-finding i use,e.g a*,dijkstra, or something special(maybe optimal),which is always time-comsuming process throughout the whole game loop ,especially massive agents on less powerfull mobile cpu. as far as i know, some game like this, shortest path is not the focus (will people care about the path agent walk through intentionally?) instead of efficient and naturally path-finding. so my mind come up with some solutions,maybe impractical.
solution 1 : use some cheaper path-finding algorithm, could be graph related or somethingelse because shortest path doesn't matter.
solution 2 : put some limits on ai module to process agent for path-finding, e.g upper limit to path-finding algorithm calls at interval,that is,just one or two agents of the those agents got planning, let rest of them plann after several game frames. as you know ,its drawback is obvious.
the above is what i thougt. hope your game dev disciplined guys give me brilliant idea , tricks, i'll appricate. thank you very much.
EDIT:
here is my related pseudo code,and procedure cresspond to my game logic.
//inside logic thread
procedure putonagent
if (need to put agent on world space)
//do standard a* path-finding for an agent
path_list=do_aStar_path_finding(attacktargetpos,startpos);
and then enqueue path_list;
......
end
the path_list's queue finally used by visual agents for stepping forward. any hints?
Look up "Hierarchical pathfinding" Say you're driving to a city far away, you don't plan the entire path before you get in the car!
Pathfinding is usually done in steps, like it's not one function call, after N iterations it'll return (and indicate it's not complete) so it can be run at the next available time. Basically rather than a function with locals think operator() and state variables as members of a class.
To make it fast you can make the heuristic crap with A* pathfinding, suppose I use a heuristic of 10* the distance-as-the-crow-flies, it may not find the shortest path but it will have a strong preference for heading towards the target rather than "fanning out" and exploring further around the closed region.

How to make a 2D Soft-body physics engine?

The definition of rigid body in Box2d is
A chunk of matter that is so strong
that the distance between any two bits
of matter on the chunk is completely
constant.
And this is exactly what i don't want as i would like to make 2D (maybe 3D eventually), elastic, deformable, breakable, and even sticky bodies.
What I'm hoping to get out of this community are resources that teach me the math behind how objects bend, break and interact. I don't care about the molecular or chemical properties of these objects, and often this is all I find when I try to search for how to calculate what a piece of wood, metal, rubber, goo, liquid, organic material, etc. might look like after a force is applied to it.
Also, I'm a very visual person, so diagrams and such are EXTREMELY HELPFUL for me.
================================================================================
Ignore these questions, they're old, and I'm only keeping them here for contextual purposes
1.Are there any simple 2D soft-body physics engines out there like this?
preferably free or opensource?
2.If not would it be possible to make my own without spending years on it?
3.Could i use existing engines like bullet and box2d as a start and simply transform their code, or would this just lead to more problems later, considering my 1 year of programming experience and bullet being 3D?
4.Finally, if i were to transform another library, would it be the best change box2D's already 2d code, Bullet's already soft code, or mixing both's source code?
Thanks!
(1) Both Bullet and PhysX have support for deformable objects in some capacity. Bullet is open source and PhysX is free to use. They both have ports for windows, mac, linux and all the major consoles.
(2) You could hack something together if you really know what you are doing, and it might even work. However, there will probably be bugs unless you have a damn good understanding of how Box2D's sequential impulse constraint solver works and what types of measures are going to be necessary to keep your system stable. That said, there are many ways to get deformable objects working with minimal fuss within a game-like environment. The first option is to take a second (or higher) order approximation of the deformation. This lets you deal with deformations in much the same way as you deal with rigid motions, only now you have a few extra degrees of freedom. See for example the following paper:
http://www.matthiasmueller.info/publications/MeshlessDeformations_SIG05.pdf
A second method is pressure soft bodies, which basically model the body as a set of particles with some distance constraints and pressure forces. This is what both PhysX and Bullet do, and it is a pretty standard technique by now (for example, Gish used it):
http://citeseerx.ist.psu.edu%2Fviewdoc%2Fdownload%3Fdoi%3D10.1.1.4.2828%26rep%3Drep1%26type%3Dpdf
If you google around, you can find lots of tutorials on implementing it, but I can't vouch for their quality. Finally, there has been a more recent push to trying to do deformable objects the `right' way using realistic elastic models and finite element type approaches. This is still an area of active research, so it is not for the faint of heart. For example, you could look at any number of the papers in this year's SIGGRAPH proceedings:
http://kesen.realtimerendering.com/sig2011.html
(3) Probably not. Though there are certain 2D style games that can work with a 3D physics engine (for example top down type games) for special effects.
(4) Based on what I just said, you should probably know the answer by now. If you are the adventurous sort and got some time to kill and the will to learn, then I say go for it! Of course it will be hard at first, but like anything it gets easier over time. Plus, learning new stuff is lots of fun!
On the other hand, if you just want results now, then don't do it. It will take a lot of time, and you will probably fail (a lot). If you just want to make games, then stick to the existing libraries and build on whatever abstractions it provides you.
Quick and partial answer:
rigid body are easy to model due to their property (you can use physic tools, like "Torseur+ (link on french on wikipedia, english equivalent points to screw theory) to modelate forces applying at any point in your element.
in comparison, non-solid elements move from almost solid (think very hard rubber : it can move but is almost solid) to almost liquid (think very soft ruber, latex). Meaning that dynamical properties applying to that knd of objects are much complex and depend of the nature of the object
Take the example of a spring : it's easy to model independantly (f=k.x), but creating a generic tool able to model that specific case is a nightmare (especially if you think of corner cases : extension is not infinite, compression reaches a lower point, material is non linear...)
as far as I know, when dealing with "elastic" materials, people do their own modelisation for their own purpose (a generic one does not exist)
now the answers:
Probably not, not that I know at least
not easily, see previously why
Unless you got high level background in elastic materials, I fear it's gonna be painful
Hope this helped
Some specific cases such as deformable balls can be simulated pretty well using spring-joint bodies:
Here is an implementation example with cocos2d: http://2sa-studio.blogspot.com/2014/05/soft-bodies-with-cocos2d-v3.html
Depending on the complexity of the deformable objects that you need, you might be able to emulate them using box2d, constraining rigid bodies with joints or springs. I did it in the past using a box2d clone for xna (farseer) and it worked nicely. Hope this helps.
The physics of your question breaks down into two different topics:
Inelastic Collisions: The math here is easy, and you could write a pretty decent library yourself without too much work for 2D points/balls. (And with more work, you could learn the physics for extended bodies.)
Materials Bending and Breaking: This will be hard. In general, you will have to model many of the topics in Mechanical Engineering:
Continuum Mechanics
Structural Analysis
Failure Analysis
Stress Analysis
Strain Analysis
I am not being glib. Modeling the bending and breaking of materials is, in general, a very detailed and varied topic. It will take a long time. And the only way to succeed will be to understand the science well enough that you can make clever shortcuts in limiting the scope of the science you need to model in your game.
However, the other half of your problem (modeling Inelastic Collisions) is a much more achievable goal.
Good luck!

I am looking for a radio advertising scheduling algorithm / example / experience

Tried doing a bit of research on the following with no luck. Thought I'd ask here in case someone has come across it before.
I help a volunteer-run radio station with their technology needs. One of the main things that have come up is they would like to schedule their advertising programmatically.
There are a lot of neat and complex rule engines out there for advertising, but all we need is something pretty simple (along with any experience that's worth thinking about).
I would like to write something in SQL if possible to deal with these entities. Ideally if someone has written something like this for other advertising mediums (web, etc.,) it would be really helpful.
Entities:
Ads (consisting of a category, # of plays per day, start date, end date or permanent play)
Ad Category (Restaurant, Health, Food store, etc.)
To over-simplify the problem, this will be a elegant sql statement. Getting there... :)
I would like to be able to generate a playlist per day using the above two entities where:
No two ads in the same category are played within x number of ads of each other.
(nice to have) high promotion ads can be pushed
At this time, there are no "ad slots" to fill. There is no "time of day" considerations.
We queue up the ads for the day and go through them between songs/shows, etc. We know how many per hour we have to fill, etc.
Any thoughts/ideas/links/examples? I'm going to keep on looking and hopefully come across something instead of learning it the long way.
Very interesting question, SMO. Right now it looks like a constraint programming problem because you aren't looking for an optimal solution, just one that satisfies all the constraints you have specified. In response to those who wanted to close the question, I'd say they need to check out constraint programming a bit. It's far closer to stackoverflow that any operations research sites.
Look into constraint programming and scheduling - I'll bet you'll find an analogous problem toot sweet !
Keep us posted on your progress, please.
Ignoring the T-SQL request for the moment since that's unlikely to be the best language to write this in ...
One of my favorites approaches to tough 'layout' problems like this is Simulated Annealing. It's a good approach because you don't need to think HOW to solve the actual problem: all you define is a measure of how good the current layout is (a score if you will) and then you allow random changes that either increase or decrease that score. Over many iterations you gradually reduce the probability of moving to a worse score. This 'simulated annealing' approach reduces the probability of getting stuck in a local minimum.
So in your case the scoring function for a given layout might be based on the distance to the next advert in the same category and the distance to another advert of the same series. If you later have time of day considerations you can easily add them to the score function.
Initially you allocate the adverts sequentially, evenly or randomly within their time window (doesn't really matter which). Now you pick two slots and consider what happens to the score when you switch the contents of those two slots. If either advert moves out of its allowed range you can reject the change immediately. If both are still in range, does it move you to a better overall score? Initially you take changes randomly even if they make it worse but over time you reduce the probability of that happening so that by the end you are moving monotonically towards a better score.
Easy to implement, easy to add new 'rules' that affect score, can easily adjust run-time to accept a 'good enough' answer, ...
Another approach would be to use a genetic algorithm, see this similar question: Best Fit Scheduling Algorithm this is likely harder to program but will probably converge more quickly on a good answer.