I have a question about writing a script which can manage to play online games in different codes. I think the easiest to understand is when I say I need to make a platform on which Playstation as xbox players are allowed to play online Modern Warfare 3 together.
Mathematically it seems it is possible: at the end you have two different screens which project the same. On the platform, Sony and Microsoft players stream their code or screen to the platform and play together. Big problem is that you get it delivered in 2 different codes which you have to translate to one language in less than 0,001 second.
Honestly said I have to get into this stuff but I cannot get much further.
Do you have any tips, other forums or solutions for this problem? Maybe it is writing a new language? (Google is technically using it for Google-translating over the phone)
Depending on the game this might not be possible even in theory. Many console games use a peer-to-peer lock-step synchronization model for multiplayer. Games that use this approach only send each other the player input from the other consoles and rely on deterministic simulation (the same inputs produce the same outputs) to keep the systems synchronized.
This only works when the exact same compiled code is running on the same CPU for all players. Games with this networking model usually have periodic desynch checks to make sure that the different systems haven't drifted out of sync with each other. A desynch failure is usually considered a fatal error and either a bug in the game or evidence of attempted cheating by one of the players.
Other multiplayer games use a client server model and so it would be possible in theory to allow different consoles to play against each other. Reverse engineering the network protocol would be a formidable technical challenge however and it would be a difficult problem to get this to work reliably.
Even if you could solve the technical problems though you would likely have even bigger legal issues to overcome. Sony and Microsoft don't want to allow cross platform play so even though it would be possible in theory to make this work with a client server multiplayer game developers aren't able to implement it. A third party trying to make this work would likely have to deal with legal challenges from Microsoft, Sony and the game developer.
Related
For those not in the know, Spaceteam is a very popular and very fun multiplayer game for iOS.
It allows for real time gameplay among multiple devices on an ad-hoc Wifi network - how does it do this?
Are there published libraries describing how to build protocols on top of ad-hoc networking libraries? Is it iOS specific, or would it be possible to build a variety of applications across different platforms?
Quickly, answer before we hit the asteroid!
Specifically which aspect are you interested in? There's nothing particularly special about mobile devices or ad hoc Wi-Fi networks (except in an ad hoc network, not all devices may be able to communicate with each other, so some mesh networking can help but unnecessarily complicates matters for the normal case).
I'll answer the broader question first, because it's more interesting. In my experience, there are a handful of major considerations:
Server/client or peer-to-peer? By this I mean whether there's a "master" deciding the true state of the world and communicating this to all clients. Avara is the only game I know of that is "peer-to-peer" in this sense (peers sent commands to all other peers; this proved bandwidth-heavy for modem users on 6-player games). I am not aware of games using more sophisticated network topologies to communicate game state (e.g. only sending data to one client on each LAN).
What do you do about latency? Avara is the only game I know of which lags everyone locally by the "latency tolerance" in order to get a consistent state of the world, which was terrible if someone was on a modem (turning off compression helped a lot). There are various ways to do "latency compensation" (e.g. in Half-Life/CS), some of which could also work on peer-to-peer games.
Time sync? For client-server games, you at least need to worry about a changing RTT. For peer-to-peer games, I think you also want to agree on timing that minimizes the effective maximum latency.
What if clients disagree about the state of the world? Avara just lets peers decide on their own state of the world (and displays "reality fragmentation detected" if it senses a mismatch, which might happen due to dropped packets or a too-low "latency tolerance").
What if a player leaves? For a P2P game, you might have to agree on a consistent game state (e.g. if the player was disconnected after sending commands to a subset of other peers). For a client-server game, you might have to elect a new master.
And now, after watching the Spaceteam trailer:
I have no idea how it works, since I haven't reverse-engineered the protocol. However, it's pretty simple to make something that works well enough:
Use some sort of P2P discovery to find players (e.g. Bonjour; there should be plenty of docs and samples out there).
Communicate with peers. I've done this with GameKit circa iOS 3/4 (I'm not sure if it still works over Wi-Fi).
Elect a master. This can be as simple as whoever presses "ready" last attempts to be the master. In some edge cases you might have to handle failure.
Let the master decide everything. Spaceteam is not latency-sensitive; Wi-Fi latency tends to be at most a handful of milliseconds, and nobody's really going to notice if one device is slower by 100 ms (as long as the UI responds fast enough).
There is a library made by Spaceteam that does this for Unity games.
https://github.com/hengineer/CaptainsMess
The creator of Spaceteam also wrote an old blog post about Networking in Spaceteam
http://spaceteamadmirals.club/blog/the-spaceteam-networking-post/
There is an iOS only library that will connect nearby devices easily called MultipeerConnectivity https://developer.apple.com/documentation/multipeerconnectivity
If you want something that will work cross-platform I have an example app here: https://github.com/brendaninnis/LocalNetworkingApp, which I explain in great detail here: http://brendaninnis.ca/connect-nearby-devices-part-1.html
I'm trying to create an 'auto dj' application that would let smartphone users select a playlist of songs, and it would create a seamless mix for playback. There are a couple factors involved in this: read a playlist of audio files, calculate their waveforms/spectrums, determine the BPMs, and organize the compatible songs in a new playlist in the order that they will be played (based on compatible tempos & keys).
The app would have to be able to scan the waveform of a song and recognize the beginning of the 'main' part of the song (skipping slow intros/outros). I also imagine having some effects: filtering, so it can filter the bass out of the new track being mixed in, and switch the basses at an appropriate time. Perhaps reverb that the user could control as well.
I am just seeing how feasible of a project this is for 3-4 busy college students in the span of ~4 months. Not sure if it would be an Android or iOS app, or perhaps even a Windows app. Not sure what language we would use (likely Python or Java); whichever has the most useful audio analyzing libraries. Obviously it would work better for certain genres of music (house, trance), but I'd still really like to try to create this.
Thanks for any feedback
As much as I would like to hear a more experienced person's opinion on this, I would say based on your situation that it would be a very big undertaking. Since it sounds like you don't have experience using audio analyzing libraries/ programs you might want to start experimenting with those and most of them are likely going to be in C/ C++, not java/ Python. Here are some I know of but I would recommend do your own research.
http://www.underbit.com/products/mad/
http://audacity.sourceforge.net/
It doesn't sound that feasible in your situation but that just depends on your programming/project experience and motivation to create it.
Good luck
I am trying to build an app that allows the user to record individual people speaking, and then save the recordings on the device and tag each record with the name of the person who spoke. Then there is the detection mode, in which i record someone and can tell whats his name if he is in the local database.
First of all - is this possible at all? I am very new to iOS development and not so familiar with the available APIs.
More importantly, which API should I use (ideally free) to correlate between the incoming voice and the records I have in the local db? This should behave something like Shazam, but much more simple since the database I am looking for a match against is much smaller.
If you're new to iOS development, I'd start with the core app to record the audio and let people manually choose a profile/name to attach it to and worry about the speaker recognition part later.
You obviously have two options for the recognition side of things: You can either tie in someone else's speech authentication/speaker recognition library (which will probably be in C or C++), or you can try to write your own.
How many people are going to use your app? You might be able to create something basic yourself: If it's the difference between a man and a woman you could probably figure that out by doing an FFT spectral analysis of the audio and figure out where the frequency peaks are. Obviously the frequencies used to enunciate different phonemes are going to vary somewhat, so solving the general case for two people who sound fairly similar is probably hard. You'll need to train the system with a bunch of text and build some kind of model of frequency distributions. You could try to do clustering or something, but you're going to run into a fair bit of maths fairly quickly (gaussian mixture models, et al). There are libraries/projects that'll do this. You might be able to port this from matlab, for example: https://github.com/codyaray/speaker-recognition
If you want to take something off-the-shelf, I'd go with a straight C library like mistral, as it should be relatively easy to call into from Objective-C.
The SpeakHere sample code should get you started for audio recording and playback.
Also, it may well take longer for the user to train your app to recognise them than it's worth in time-saving from just picking their name from a list. Unless you're intending their voice to be some kind of security passport type thing, it might just not be worth bothering with.
What sort of application can be considered to be the really business winner for automotive telematics applications related to image processing/computer vision ?
here are the criteria :
1. Innovative
2. Social
3. Fun.
Have you read the articles from the DARPA grand challenge winners?
DARPA site
Google Scholar
I believe the "DARPA Grand Challenge" style of automation meets your .1 requirement as there are plenty of innovation on that front.
But I still think that we are a good decade away from a fully autonomous vehicle, even though the technology is almost there. The main reason is that people are still very afraid of relenting control to the computer, even though it might be the safest choice.
The transition will be slow. More and more models will bring small chunks of automation, such as smarter cruise control systems (that's a big winner right now), autonomous parking (in the market for a while now) and anti collision systems.
Which brings us to your .2 and .3
The above mentioned systems are not fun, they are necessary [for increased safety]. Nowadays, Social Media and Fun don't really mix with driving because they distract the driver from its main task. In the future, when you're on the freeway in auto-pilot mode, you will be able to open your laptop and be free to do whatever you want, since computers will be always connected to the internet. So I don't believe the car itself needs to provide you that aspect of entertainment.
What I do believe it's a killer functionality for cars is the enhancement of intelligent comfort systems integrated with biometrics. Nowadays, cars already have things like personal keys that will make it adjust things like seat height and etc according to your preferences, but it would be much nicer if it could automatically identify who is the driver by some biometric feature (iris, etc) and adjust multiple parameters automatically. That's the end of the key. I'm not talking about seat and pedals adjustment, but transmission style (husband likes a more aggressive transmission), performance limiters (daughter cannot exceed 90% of posted limit... the car knows what the limit is according to where it is).
In my opinion, if you implement biometric recognition + autonomous navigation, the possibilities are endless.
Although none of the applications here use computer vision, they are probably the best once out there yet. They have received quite a bit of media hype.
Can XNA and C# be used to create commercially feasible PC/XBOX games?
Is it the best approach for creating 3D games with C#? If not, what would be?
Actually you can do that but it is a little bit tricky.
You need to pass via an approval process by the "community" (XNA Creators club Online users).
You will also need to pay an Xbox live account plus an Xbox live developper licence.
According to XNA FAQ:
Do I need an XNA Creators Club premium membership to create games?
You don't need a premium membership to make games for Windows or Zune. However, you must be a premium member and in a supported region to create games for the Xbox 360, to release Xbox 360 games to Community Games on Xbox LIVE, or to peer-review submitted games.
Who can peer review XNA Community Games?
A member of the Creators Club whose premium (paid) account is in good standing and is a legal adult (for the countries we currently serve this means 18 years of age or older).
And:
Why does my game have to be peer-reviewed? Why can't I just send it to Xbox LIVE marketplace?
Peer reviewers help creators write better games, and protect game players from experiencing highly offensive or malfunctioning games. Peer reviewers will reject your game if:
Your game contains prohibited content, which is content not allowed on Xbox LIVE services
You misrepresent what is in the game play or in the promotional materials for the game
The promotional content for your game ( for example, the box art, description, banner or title) is not appropriate for all ages on Xbox LIVE Marketplace
The game crashes, it has too many bugs, or it is technically defective in some way
the faq is can be read here
If you want to do it simplier you can play with DirectX directly or even other libraries like SDL (for 2D games). Actually C# is very good for a variety of things and it gets better as the time goes.
A short answer to your first question would be, yes. It is entirely possible to create just about any kind of game with the XNA library. It can be used to make simple 2D platformers, or moderatily complex 3D shooters.
Depending on the game, the amount of logic you'll need to create for your game may vary.
Of course, while creating 3D games, you'll either have to create your own 3D engine, or get your hands on one pre made. XNA in and on itself does not provide an engine that would be fully usable out of the box. It does, however, provide wide variety of tool to help you in the process of making your own engine.
XNA is dedicated primarily to garage games, small projects with small teams, and hobbyists. Also, it's a really good learning tool for game architecture and 3D programming. But for commercial applications, there's a clearly huge gap between the XLA and the XDK.
Using the XDK allows you to access to a much deeper level of hardware, which is definitively a must if performances are an issue. Also, most of commercial game engines are developed for use with the XDK (the Unreal Engine, for example). The debugging and profiling system of the XDK is also an amazing tool which is not available using XLA.
So yes, it is technically possible to make commercial games using XNA, but the real world tends to prefer the XDK.
C# is not that much slower than C++, however C#'s memory management is not really Game friendly (in the AAA style). Never the less rendering is basically the same, as you'll be using DirectX I guess, so there is no reason a very professional game like Gear of Wars couldn't be made with C# (As a game dev my self, I've seen the source code for Gears of War, and can tell you this first hand). But you'll need great artists.
The real roadblock, is if your source is in C#, you have just locked your self out of other Platforms that aren't from Microsoft (Say Sony or Nintendo), but then again GoW is Microsoft bound, ASFAIK.
As for XNA, the best selling Arcade/Community Game Braid, was written in C++, but that's because the author didn't want to lock himself out of other platforms, and he had lots of experience and a large code-base that was already C++ based
XNA saves you a lot of the low level tedium associated with making games. This can be a huge time savings for a handful of people banging out games that don't need to push the hardware to its limit; however, most AAA games require a few people getting down and dirty with the hardware to push the limit as much as they can.
Having said that by no means does your game have to be AAA to be commercially feasible or fun - one could even argue it hurts more than it helps. Technology is rarely the bottleneck of making good games.
I doubt you will create the next Gears of War with it, but XNA works fine for many types of games. Most (all?) of the Community Games on XBox Live are created using XNA.