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  • Static DataTable or DataSet in a class - bad idea?

    - by Superbest
    I have several instances of a class. Each instance stores data in a common database. So, I thought "I'll make the DataTable table field static, that way every instance can just add/modify rows to its own table field, but all the data will actually be in one place!" However, apparently it's a bad idea to do use static fields, especially if it's databases: Don't Use "Static" in C#? Is this a bad idea? Will I run into problems later on if I use it? This is a small project so I can accept no testing as a compromise if that is the only drawback. The benefit of using a static database is that there can be many objects of type MyClass, but only one table they all talk to, so a static field seems to be an implementation of exactly this, while keeping syntax concise. I don't see why I shouldn't use a static field (although I wouldn't really know) but if I had to, the best alternative I can think of is creating one DataTable, and passing a reference to it when creating each instance of MyClass, perhaps as a constructor parameter. But is this really an improvement? It seems less intuitive than a static field.

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  • Do you leverage the benefits of the open-closed principle?

    - by Kaleb Pederson
    The open-closed principle (OCP) states that an object should be open for extension but closed for modification. I believe I understand it and use it in conjunction with SRP to create classes that do only one thing. And, I try to create many small methods that make it possible to extract out all the behavior controls into methods that may be extended or overridden in some subclass. Thus, I end up with classes that have many extension points, be it through: dependency injection and composition, events, delegation, etc. Consider the following a simple, extendable class: class PaycheckCalculator { // ... protected decimal GetOvertimeFactor() { return 2.0M; } } Now say, for example, that the OvertimeFactor changes to 1.5. Since the above class was designed to be extended, I can easily subclass and return a different OvertimeFactor. But... despite the class being designed for extension and adhering to OCP, I'll modify the single method in question, rather than subclassing and overridding the method in question and then re-wiring my objects in my IoC container. As a result I've violated part of what OCP attempts to accomplish. It feels like I'm just being lazy because the above is a bit easier. Am I misunderstanding OCP? Should I really be doing something different? Do you leverage the benefits of OCP differently? Update: based on the answers it looks like this contrived example is a poor one for a number of different reasons. The main intent of the example was to demonstrate that the class was designed to be extended by providing methods that when overridden would alter the behavior of public methods without the need for changing internal or private code. Still, I definitely misunderstood OCP.

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  • How do you keep SOA DRY?

    - by TaylorOtwell
    In our organization, we've shifted to a more "service oriented architecture". To give an example, let's assume we need to retrieve a "Quote" object. This quote has a shipper, a consignee, phone numbers, contacts, email addresses, and other location information. In other words, a Quote object is made up of many other objects. So, it seems like it would make sense to make a "Quote Retrieval Service". In our situation, we've accomplished this by creating a .NET solution and writing the service. The service API looks something like this (in pseudo-code): Function GetQuote(String ID) Returns Quote So, so far so good. Now, when this service is consumed, to keep things "de-coupled", we are creating essentially a duplicate of the Quote object and mapping from the QuoteService version of the Quote into the consumer's version of the Quote. In many cases, these classes will have the exact same properties. So, if the Quote service is consumed by 5 other applications, we would have 6 definitions of what a "Quote" is. One for each consumer, and one for the service. This feels wrong. I thought code was supposed to be DRY, but it seems like our method of SOA is forcing us to create tons of duplicated class definitions. What are we doing wrong, or is the code duplication just a "necessary evil" of SOA?

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  • What should a domain object's validation cover?

    - by MarcoR88
    I'm trying to figure out how to do validation of domain objects that need external resources, such as data mappers/dao Firstly here's my code class User { const INVALID_ID = 1; const INVALID_NAME = 2; const INVALID_EMAIL = 4; int getID(); void setID(Int i); string getName(); void setName(String s); string getEmail(); void setEmail(String s); int getErrorsForInsert(); // returns a bitmask for INVALID_* constants int getErrorsForUpdate(); } My worries are about the uniqueness of the email, checking it would require the storage layer. Reading others' code seems that two solutions are equally accepted: both perform the unique validation in data mapper but some set an error state to the DO user.addError(User.INVALID_EMAIL) while others prefer to throw a totally different type of exception that covers only persistence, like: UserStorageException { const INVALID_EMAIL = 1; const INVALID_CITY = 2; } What are the pros and cons of these solutions?

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  • Limiting the speed of the mouse cursor

    - by idlewire
    I am working on a simple game where you can drag objects around with the mouse cursor. As I drag the object around quickly, I notice there is some juddering, which seems to be due to the fact that I can move the mouse cursor faster than the game's update/draw. So, although I maintain the offset from where the player initially clicked on the object, the mouse's relative position to the object shifts around slightly before settling as I move the object very quickly. The only way I have found to get smooth, exact 1:1 movement is if I turn both IsFixedTimeStep and SynchronizeWithVerticalRetrace to false. However, I'd rather not have to do that. I have also tried making a custom mouse cursor, hiding the real mouse, taking the real mouse delta and clamping it to a maximum speed. Here is the problem: In windowed mode, the "real" mouse cursor moves off the window while the custom mouse cursor (since it's movement is being scaled) is still somewhere inside the game window. This becomes bizarre and is obviously not desired, as clicking at this point means clicking on things outside the game window. Is there any way to accomplish this in windowed mode? In fullscreen mode, the "real" mouse cursor is bounded to the edges of the screen. So I get to a point where there is no more mouse delta, yet my custom cursor is still somewhere in the middle of the screen and hence can't move further in that direction. If I wanted to clamp it to the edge of the screen when the real cursor is at the edge, then I would get an abrupt jump to the edge of the screen, which isn't desired either Any help would be appreciated. I'd like to be able to limit the speed of the mouse, but also would appreciate help with the first issue (the non-smooth relative offset between mouse cursor movement and object movement).

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  • I've been told that Exceptions should only be used in exceptional cases. How do I know if my case is exceptional?

    - by tieTYT
    My specific case here is that the user can pass in a string into the application, the application parses it and assigns it to structured objects. Sometimes the user may type in something invalid. For example, their input may describe a person but they may say their age is "apple". Correct behavior in that case is roll back the transaction and to tell the user an error occurred and they'll have to try again. There may be a requirement to report on every error we can find in the input, not just the first. In this case, I argued we should throw an exception. He disagreed, saying, "Exceptions should be exceptional: It's expected that the user may input invalid data, so this isn't an exceptional case" I didn't really know how to argue that point, because by definition of the word, he seems to be right. But, it's my understanding that this is why Exceptions were invented in the first place. It used to be you had to inspect the result to see if an error occurred. If you failed to check, bad things could happen without you noticing. Without exceptions every level of the stack needs to check the result of the methods they call and if a programmer forgets to check in one of these levels, the code could accidentally proceed and save invalid data (for example). Seems more error prone that way. Anyway, feel free to correct anything I've said here. My main question is if someone says Exceptions should be exceptional, how do I know if my case is exceptional?

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  • Designing a plug-in system

    - by madflame991
    I'm working on a Java project and I would like to add a plug-in system. More precisely, I would like to let the user design his own module, pack it into a jar, leave it in a "plugins/" subfolder of my application and be done with it. I've managed to get a child classloader to instantiate objects of classes located in external jars, but now I'm facing a design dilemma: Say Joe makes a plug-in and he packs it in joeplugin.jar. I would really like Joe to have a class named "instantiation.Factory" and I would also like everyone to have this class with this exact location and name. (This factory class obviously implements a interface that I provide and through it I get what I want from the plug-in.) If Joe wouldn't be restricted in this way I would have to look into his entire jar for some class that implements my factory interface and I don't want to imagine how complicated things get. So my question is: should I enforce a strict naming convention for this single class? I have no idea how plug-in systems work.

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  • Download the Anime Angels Theme for Windows 7

    - by Asian Angel
    Do you have a passion for all things anime? Then you will definitely want to have a look at the Anime Angels Theme for Windows 7. This cute theme will give your desktop that extra bit of fun and spunk to help bring a smile to your face. The theme comes with 21 Hi-Res wallpapers of the cutest Anime Angels from around the web, a wonderful set of anime icons, and great system sounds to round out the perfect anime theme. Anime Angels Theme For Windows (Anime Themes) [VikiTech] Latest Features How-To Geek ETC How To Remove People and Objects From Photographs In Photoshop Ask How-To Geek: How Can I Monitor My Bandwidth Usage? Internet Explorer 9 RC Now Available: Here’s the Most Interesting New Stuff Here’s a Super Simple Trick to Defeating Fake Anti-Virus Malware How to Change the Default Application for Android Tasks Stop Believing TV’s Lies: The Real Truth About "Enhancing" Images The Legend of Zelda – 1980s High School Style [Video] Suspended Sentence is a Free Cross-Platform Point and Click Game Build a Batman-Style Hidden Bust Switch Make Your Clock Creates a Custom Clock for your Android Homescreen Download the Anime Angels Theme for Windows 7 CyanogenMod Updates; Rolls out Android 2.3 to the Less Fortunate

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  • Android From Local DB (DAO) to Server sync (JSON) - Design issue

    - by Taiko
    I sync data between my local DB and a Server. I'm looking for the cleanest way to modelise all of this. I have a com.something.db package That contains a Data Helper and couple of DAO classes that represents objects stored in the db (I didn't write that part) com.something.db --public DataHelper --public Employee @DatabaseField e.g. "name" will be an actual column name in the DB -name @DatabaseField -salary etc... (all in all 50 fields) I have a com.something.sync package That contains all the implementation detail on how to send data to the server. It boils down to a ConnectionManager that is fed by different classes that implements a 'Request' interface com.something.sync --public interface ConnectionManager --package ConnectionManagerImpl --public interface Request --package LoginRequest --package GetEmployeesRequest My issue is, at some point in the sync process, I have to JSONise and de-JSONise my data (E.g. the Employee class). But I really don't feel like having the same Employee class be responsible for both his JSONisation and his actual representation inside the local database. It really doesn't feel right, because I carefully decoupled the rest, I am only stuck on this JSON thing. What should I do ? Should I write 3 Employee classes ? EmployeeDB @DatabaseField e.g. "name" will be an actual column name in the DB -name @DatabaseField -salary -etc... 50 fields EmployeeInterface -getName -getSalary -etc... 50 fields EmployeeJSON -JSON_KEY_NAME = "name" The JSON key happens to be the same as the table name, but it isn't requirement -name -JSON_KEY_SALARY = "salary" -salary -etc... 50 fields It feels like a lot of duplicates. Is there a common pattern I can use there ?

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  • Red Samurai Performance Audit Tool – OOW 2013 release (v 1.1)

    - by JuergenKress
    We are running our Red Samurai Performance Audit tool and monitoring ADF performance in various projects already for about one year and the half. It helps us a lot to understand ADF performance bottlenecks and tune slow ADF BC View Objects or optimise large ADF BC fetches from DB. There is special update implemented for OOW'13 - advanced ADF BC statistics are collected directly from your application ADF BC runtime and later displayed as graphical information in the dashboard. I will be attending OOW'13 in San Francisco, feel free to stop me and ask about this tool - I will be happy to give it away and explain how to use it in your project. Original audit screen with ADF BC performance issues, this is part of our Audit console application: Audit console v1.1 is improved with one more tab - Statistics. This tab displays all SQL Selects statements produced by ADF BC over time, logged users, AM access load distribution and number of AM activations along with user sessions. Available graphs: Daily Queries  - total number of SQL selects per day Hourly Queries - Last 48 Hours Logged Users - total number of user sessions per day SQL Selects per Application Module - workload per Application Module Number of Activations and User sessions - last 48 hours - displays stress load Read the complete article here. WebLogic Partner Community For regular information become a member in the WebLogic Partner Community please visit: http://www.oracle.com/partners/goto/wls-emea ( OPN account required). If you need support with your account please contact the Oracle Partner Business Center. Blog Twitter LinkedIn Mix Forum Wiki Technorati Tags: Red Samurai,ADF performance,WebLogic,WebLogic Community,Oracle,OPN,Jürgen Kress

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  • Adult Swim Brings Their Programming Lineup to iOS Devices

    - by ETC
    If you’re a fan of the programming lineup on Adult Swim–such as Family Guy, Aqua Teen Hunger Force, and The Boondocks–you can now get the entire lineup for free on your iOS device. Adult Swim’s new iOS app streams Adult Swim’s programming lineup including popular shows such as Robot Chicken, Aqua Teen Hunger Force, Family Guy, The Boondocks, Metalocalypse. Hit up the link below to read more and grab a free copy. Adult Swim [iTunes App Store via Download Squad] Latest Features How-To Geek ETC What Can Super Mario Teach Us About Graphics Technology? Windows 7 Service Pack 1 is Released: But Should You Install It? How To Make Hundreds of Complex Photo Edits in Seconds With Photoshop Actions How to Enable User-Specific Wireless Networks in Windows 7 How to Use Google Chrome as Your Default PDF Reader (the Easy Way) How To Remove People and Objects From Photographs In Photoshop Make Efficient Use of Tab Bar Space by Customizing Tab Width in Firefox See the Geeky Work Done Behind the Scenes to Add Sounds to Movies [Video] Use a Crayon to Enhance Engraved Lettering on Electronics Adult Swim Brings Their Programming Lineup to iOS Devices Feel the Chill of the South Atlantic with the Antarctica Theme for Windows 7 Seas0nPass Now Offers Untethered Apple TV Jailbreaking

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  • SQL language drawbacks, The Third Manifesto

    - by David Portabella
    Sometime ago I read about SQL language drawbacks (the basic language specification, not vendor specific), and one of the drawbacks was that the language does not allow to create a set of tuples that don't come from a table. For instance, SELECT firstName, lastName from people; this creates a set of tuples coming from the table people. Now, if I don't have this table people, and I want to return a constant, I'd need something like this to return a set of two tuples (this would not require to have a table): SELECT VALUES('james', 'dean'), ('tom', 'cruisse'); Why I would need that? Because of the same reasons that we can define constants (not only basic types, but objects and arrays also) in any advanced programming language. Workarounds, Yes, I could create a temporal table, fill the data, and SELECT from that table. This is a hack, to overcome the drawbacks of the poor SQL language. I think that I read about this somewhere in "The Third Manifesto", but I don't find the paragraph/example talking about this concrete drawback anymore. Do you know a reference about it?

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  • Using visitor pattern with large object hierarchy

    - by T. Fabre
    Context I've been using with a hierarchy of objects (an expression tree) a "pseudo" visitor pattern (pseudo, as in it does not use double dispatch) : public interface MyInterface { void Accept(SomeClass operationClass); } public class MyImpl : MyInterface { public void Accept(SomeClass operationClass) { operationClass.DoSomething(); operationClass.DoSomethingElse(); // ... and so on ... } } This design was, however questionnable, pretty comfortable since the number of implementations of MyInterface is significant (~50 or more) and I didn't need to add extra operations. Each implementation is unique (it's a different expression or operator), and some are composites (ie, operator nodes that will contain other operator/leaf nodes). Traversal is currently performed by calling the Accept operation on the root node of the tree, which in turns calls Accept on each of its child nodes, which in turn... and so on... But the time has come where I need to add a new operation, such as pretty printing : public class MyImpl : MyInterface { // Property does not come from MyInterface public string SomeProperty { get; set; } public void Accept(SomeClass operationClass) { operationClass.DoSomething(); operationClass.DoSomethingElse(); // ... and so on ... } public void Accept(SomePrettyPrinter printer) { printer.PrettyPrint(this.SomeProperty); } } I basically see two options : Keep the same design, adding a new method for my operation to each derived class, at the expense of maintainibility (not an option, IMHO) Use the "true" Visitor pattern, at the expense of extensibility (not an option, as I expect to have more implementations coming along the way...), with about 50+ overloads of the Visit method, each one matching a specific implementation ? Question Would you recommand using the Visitor pattern ? Is there any other pattern that could help solve this issue ?

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  • C++ and SDL Trouble Creating a STL Vector of a Game Object

    - by Jackson Blades
    I am trying to create a Space Invaders clone using C++ and SDL. The problem I am having is in trying to create Waves of Enemies. I am trying to model this by making my Waves a vector of 8 Enemy objects. My Enemy constructor takes two arguments, an x and y offset. My Wave constructor also takes two arguments, an x and y offset. What I am trying to do is have my Wave constructor initialize a vector of Enemies, and have each enemy given a different x offset so that they are spaced out appropriately. Enemy::Enemy(int x, int y) { box.x = x; box.y = y; box.w = ENEMY_WIDTH; box.h = ENEMY_HEIGHT; xVel = ENEMY_WIDTH / 2; } Wave::Wave(int x, int y) { box.x = x; box.y = y; box.w = WAVE_WIDTH; box.y = WAVE_HEIGHT; xVel = (-1)*ENEMY_WIDTH; yVel = 0; std::vector<Enemy> enemyWave; for (int i = 0; i < enemyWave.size(); i++) { Enemy temp(box.x + ((ENEMY_WIDTH + 16) * i), box.y); enemyWave.push_back(temp); } } I guess what I am asking is if there is a cleaner, more elegant way to do this sort of initialization with vectors, or if this is right at all. Any help is greatly appreciated.

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  • Deferred rendering order?

    - by Nick Wiggill
    There are some effects for which I must do multi-pass rendering. I've got the basics set up (FBO rendering etc.), but I'm trying to get my head around the most suitable setup. Here's what I'm thinking... The framebuffer objects: FBO 1 has a color attachment and a depth attachment. FBO 2 has a color attachment. The render passes: Render g-buffer: normals and depth (used by outline & DoF blur shaders); output to FBO no. 1. Render solid geometry, bold outlines (as in toon shader), and fog; output to FBO no. 2. (can all render via a single fragment shader -- I think.) (optional) DoF blur the scene; output to the default frame buffer OR ELSE render FBO2 directly to default frame buffer. (optional) Mesh wireframes; composite over what's already in the default framebuffer. Does this order seem viable? Any obvious mistakes?

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  • How can I replicate the look and limitations of the Super NES?

    - by Mikalichov
    I am looking to produce graphics with the same limitations / look that in the Super Nes era. I am specifically looking for graphics similar to Chrono Trigger / FF6. It would be a lot easier to do if I had an idea of the resolution / dpi I am supposed to use. I found that the technical specs for the SNES are: Progressive: 256 × 224, 512 × 224, 256 × 239, 512 × 239 Interlaced: 512 × 448, 512 × 478 But even by using these resolutions, it is pointless if I set it at 72dpi, as I will still have possibly very detailed graphics (that is the main thing, I don't want detailed graphics, I want to go pixelated). I figured it might be related to the sprite size limit, i.e.: Sprites can be 8 × 8, 16 × 16, 32 × 32, or 64 × 64 pixels, each using one of eight 16-color palettes and tiles from one of two blocks of 256 in VRAM. Up to 32 sprites and 34 8 × 8 sprite tiles may appear on any one line. This would work for sprites (characters, objects), but what about maps? Are they built entirely from 8x8 tiles? And then, at what resolution is the end result displayed? It might seem like I am giving the question and answers at the same time, but all of these are suppositions I am making, so could someone confirm or correct them?

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  • Must all AI states be able to react to any event?

    - by Prog
    FSMs implemented with the State design pattern are a common way to design AI agents. I am familiar with the State design pattern and know how to implement it. How is this used in games to design AI agents? Consider a simplified class Monster, representing an AI agent: class Monster { State state; // other fields omitted public void update(){ // called every game-loop cycle state.execute(this); } public void setState(State state){ this.state = state; } // irrelevant stuff omitted } There are several State subclasses implementing execute() differently. So far, classic State pattern. AI agents are subject to environmental effects and other objects communicating with them. For example, an AI agent might tell another AI agent to attack (i.e. agent.attack()). Or a fireball might tell an AI agent to fall down. This means that the agent must have methods such as attack() and fallDown(), or commonly some message receiving mechanism to understand such messages. With an FSM, the current State of the agent should be the one taking care of such method calls - i.e. the agent delegates to the current state upon every event. Is this correct? If correct, how is this done? Are all states obligated by their superclass to implement methods such as attack(), fallDown() etc., so the agent can always delegate to them on almost every event? Or is it done in some other way?

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  • Tools for game script / storyboard

    - by Pietro Polsinelli
    I am searching for a tool that will help in writing a game script. By "script" I mean the text core of a storyboard - without the drawing drafts, which may or may not be there (yet). What I'm thinking of will let write a piece of text of the script, define a simplified workflow from that step, and then define the text of next steps, and so on. Searching online, I found Inform http://inform7.com/ ("A Design System for Interactive Fiction Based on Natural Language") which in theory is exactly what I am searching for, but trying to use it it has this model of a space (a dungeon, a library) where you are picking up objects and exploring them. In my case I am designing more a Sims like game, the flow is entirely different. Considering non specific software, mind mapping tools miss the linearity of the process. What I am writing is a directed graph - simply a work-flow, but the way I want to design it is more text based than work-flow based. SO what I'm doing now is using a text editor, which I'll transform directly in code. Any suggestions?

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  • XPath & XML EDI B2B

    - by PearlFactory
    GoodToGo :) Best XML Editor is Altova XMLSpy 2011 http://www.torrenthound.com/hash/bfdbf55baa4ca6f8e93464c9a42cbd66450bb950/torrent-info/Altova-XMLSpy-Enterprise-Edition-SP1-2011-v13-0-1-0-h33t-com-Full For whatever reason Piratebay has trojans and other nasties..Search in torrent.eu for Altova XMLSpy Enterprise Edition SP1 2011 v13.0.1.0 Also if you like the product purchase it in a Commercial Enviroment Any well structured/complex XML can be parsed @ the speed of light using XPATH querys and not the C# objects XPathNodeIterator and others etc ....Never do loops  or Genirics or whatever highlevel language technology. Use the power of XPATH i.e Will use a Simple (Do while) as an example. We could have many different techs all achieveing the same result Instead of   xmlNI2 = xmlNav.Select("/p:BookShop")         if (xmlNI2.Count != 0)            {                                 while ((xmlNI2.MoveNext()))              string aNode =xmlNI2.SelectSingleNode('Book', nsmgr); if (aNode =="The Book I am after")       Console.WriteLine("Found My Book);   This lengthy cumbersome task can be achieved with a simple XPATH query Console.WriteLine((xmlNavg.SelectSingleNode("/p:BookShop/Book[.='The Book I am aFter ']", nsmgr)).Value.ToString()); Use the power of the parser and eliminate the middleman C#/MSIL/JIT etc etc Get Started Fast and use the parser as Outlined 1) Open XML and goto Grid Mode 2) Select XPATH tab on the bottom viewer/window as shown  From here you get intellisense and can quickly learn how to navigate/find the data using XPATH A key component to Navigation with XPATH is to use the "../ " command . This basically says from where I am now go up 1 level . With Xpath all commands are cumalative. i.e you can search for a book title @ the 2nd level of the XML and from there traverse 15 layers to paragraphs or words on a page with expression validation occuring throughout this process etc  (So in essence you may have arrived @ a node within the XML and have met 15 conditions along the way ) Given 1-2 days with XmlSpy and XPATH you unlock a technology that is super fast and simple to use. XML is a core component to what lays under the hood of so many techs. So it is no wonder that you want to be able to goto  the atomic level to achieve the result you want Justin P.S For a long time I saw XML as slow and a bit boring but now converted

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  • OOP implementation of BUFFS and Stats. Suggestion

    - by Mattia Manzo Manzati
    I am developing an MMORPG server using NodeJS. I am not sure how to implement Buffs, i mean, equipped objects or used skills have effects on the Player() which has many Stats(), some of them have a max cap... Effects can change the Stat value, increasing or decreasing it by a value, a percentage or completly rewrite the value of the stat. After a while I have decided to create a base class for buffs, which can be hidden (if they are casted from an equipped object) or shown if they came from an ability (Spell). Anyway I need suggestion how to implement it, use an array for all active buffs for a stat and have a function calculate the value of the stat affected by buffs each time I need the value of the stat or...? Other more OOP's ways to do it? I have read this What's a way to implement a flexible buff/debuff system? but this implements only a percentage system, which buffs can only say "+10%, +20%, etc...", but I would love to have an hybrid system, which can have percentage values or static values (like WoW does), and using modifiers it's hard to implement, because modifiers refers to the current value of stat :/ Thanks for suggestions :)

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  • How to manage many mobile device users at server side?

    - by Rami
    I built a social Android application in which users can see other users around them by GPS location. At the beginning thing went well as I had low number of users, but now that I have increasing number of users (about 1500 +100 every day) it has revealed a major problem in my design. In my Google App Engine servlet I have static HashMap that holds all the users profiles objects, currently 1500 and this number will increase as more users register. Why I'm doing it? Every user that requests for the users around him compares his GPS with other users and checks if they are in his 10km radius. This happens every five minutes on average. Consequently, I can't get the users from db every time because GAE read/write operation quota will tear me apart. The problem with this design is? As the number of users increases, the Hashmap turns to null every 4-6 hours, I think that this time is getting shorter, but I'm not sure. I'm fixing this by reloading the users from the db every time I detect that it becomes null, but this causes DOS to my users for 30 sec, so I'm looking for better solution. I'm guessing that it happens because the size of the hashmap. Am I right? I have been advised to use a spatial database, but that means that I can't work with GAE any more and it means that I need to build my big server all over again and lose my existing DB. Is there something I can do with the existing tools? Thanks.

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  • Should I build a multi-threaded system that handles events from a game and sorts them, independently, into different threads based on priority?

    - by JonathonG
    Can I build a multi-threaded system that handles events from a game and sorts them, independently, into different threads based on priority, and is it a good idea? Here's more info: I am about to begin work on porting a mid-sized game from Flash/AS3 to Java so that I can continue development with multi-threading capabilities. Here's a small bit of background about the game: The game contains numerous asynchronous activities, such as "world updating" (the game environment is constantly changing based on a set of natural laws and forces), procedural generation of terrain, NPCs, quests, items, etc., and on top of that, the effects of all of the player's interactions with his environment are programmatically calculated in real time, based on a set of constantly changing "stats" and once again, natural laws and forces. All of these things going on at once, in an asynchronous manner, seem to lend themselves to multi-threading very well. My question is: Can I build some kind of central engine that handles the "stacking" of all of these events as they are triggered, and dynamically sorts them out amongst the available threads, and would it be a good idea? As an example: Essentially, every time something happens (IE, a magic missile being generated by a spell, or a bunch of plants need to grow to their next stage), instead of just processing that task right then and adding the new object(s) to a list of managed objects, send a reference to that event to a core "event handler" that throws it into a stack of all other currently queued events, which then sorts them out and orders them according to urgency, splits them between a number of available threads for as-fast-as-possible multithreaded execution.

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  • How to perform game object smoothing in multiplayer games

    - by spaceOwl
    We're developing an infrastructure to support multiplayer games for our game engine. In simple terms, each client (player) engine sends some pieces of data regarding the relevant game objects at a given time interval. On the receiving end, we step the incoming data to current time (to compensate for latency), followed by a smoothing step (which is the subject of this question). I was wondering how smoothing should be performed ? Currently the algorithm is similar to this: Receive incoming state for an object (position, velocity, acceleration, rotation, custom data like visual properties, etc). Calculate a diff between local object position and the position we have after previous prediction steps. If diff doesn't exceed some threshold value, start a smoothing step: Mark the object's CURRENT POSITION and the TARGET POSITION. Linear interpolate between these values for 0.3 seconds. I wonder if this scheme is any good, or if there is any other common implementation or algorithm that should be used? (For example - should i only smooth out the position? or other values, such as speed, etc) any help will be appreciated.

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  • Moving characters on a grid [on hold]

    - by madmax1
    i am developing my first game with C++. My game uses a grid of rectangles. I have a class Board which manages the grid as a whole, initializes the terrain, places/removes characters, etc. It has a 2D vector of a class Field, which handles the Structure of the field, contained Objects, Characters, etc. Field again contains a vector of class Character, which are positioned on the field. Now i want to implement the functionality to move a character on the board, however dont know which is best practice to do so. Should i implement a moveCharacter(character, offset) function in Board, make it search for the character and move it? Or should i implement a function move(offset) in Character? This sure would be nicest, however makes characters necessary to know the board they are on, or the field which in turn knows the board. On the one hand i feel like i should avoid inclusion between classes as much as possible e.g. to increase portability of classes for different projects, on the other hand i think the character.move() functionality is most comfortable for further development. Im pretty new to "bigger" C++ projects and these kind of design questions pop up more and more often lately and i have troubles deciding. Thanks a lot for any advice!

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  • PhysX Capsule Character Controller floating above ground

    - by Jannie
    I am using PhysX Version 3.0.2 in the simulation package I'm working on, and I've encountered some bizarre behavior with the capsule character controller. When I set the controller's height and radius to the appropriate values (r = 0.25, h = 1.86)it behaves correctly (moving along the ground, colliding with other objects, and so on) except that the capsule itself is floating above the ground. The actor will then bump his head when trying to get through a door, since the capsule is the correct height but also floating above the ground. This image should illustrate what I'm going on about: One can clearly see that the rest of the scene has their collision bodies wrapped correctly, it's just the capsule that's going wrong! The stop-gap I've implemented is creating a smaller capsule and giving it an offset, but I need to implement ray-picking for the controller next so the capsule has to surround the character model properly. Here's my character creation code (with height = 1.86f and radius = 0.25f): NxController* D3DPhysXManager::CreateCharacterController( std::string l_stdsControllerName, float l_fHeight, float l_fRadius, D3DXVECTOR3 l_v3Position ) { NxCapsuleControllerDesc l_CapsuleControllerDescription; l_CapsuleControllerDescription.height = l_fHeight; l_CapsuleControllerDescription.radius = l_fRadius; l_CapsuleControllerDescription.position.set( l_v3Position.x, l_v3Position.y, l_v3Position.z ); l_CapsuleControllerDescription.callback = &this->m_ControllerHitReport; NxController* l_pController = this->m_pControllerManager->createController( this->m_pScene, l_CapsuleControllerDescription ); this->m_pControllerMap.insert( l_ControllerValuePair( l_stdsControllerName, l_pController ) ); return l_pController; } Any help at all would be appreciated, I just can't figure this one out! P.S. I've found a couple of (rather old) threads describing the same issue, but it seems they couldn't find a solution either. Here are the links: http://forum-archive.developer.nvidia.com/index.php?showtopic=6409 http://forum-archive.developer.nvidia.com/index.php?showtopic=3272 http://www.ogre3d.org/addonforums/viewtopic.php?f=8&t=23003

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