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• How do I properly implement zooming in my game?

  - by Rudy_TM

  I'm trying to implement a zoom feature but I have a problem. I am zooming in and out a camera with a pinch gesture, I update the camera each time in the render, but my sprites keep their original position and don't change with the zoom in or zoom out. The Libraries are from libgdx. What am I missing? private void zoomIn() { ((OrthographicCamera)this.stage.getCamera()).zoom += .01; } public boolean pinch(Vector2 arg0, Vector2 arg1, Vector2 arg2, Vector2 arg3) { // TODO Auto-generated method stub zoomIn(); return false; } public void render(float arg0) { this.gl.glClear(GL10.GL_DEPTH_BUFFER_BIT | GL10.GL_COLOR_BUFFER_BIT); ((OrthographicCamera)this.stage.getCamera()).update(); this.stage.draw(); } public boolean touchDown(int arg0, int arg1, int arg2) { this.stage.toStageCoordinates(arg0, arg1, point); Actor actor = this.stage.hit(point.x, point.y); if(actor instanceof Group) { ((LevelSelect)((Group) actor).getActors().get(0)).touched(); } return true; } Zoom In Zoom Out

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• The architecture and technologies to use for a secure, fast, reliable and easily scalable web application

  - by DSoul

  ^ For actual questions, skip to the lists down below I understand, that his is a vague topic, but please, before you turn the other way and disregard me, hear me out. I am currently doing research for a web application(I don't know if application is the correct word for it, but I will proceed w/ that for now), that one day might need to be everything mentioned in the title. I am bound by nothing. That means that every language, OS and framework is acceptable, but only if it proves it's usefulness. And if you are going to say, that scalability and speed depend on the code I write for this application, then I agree, but I am just trying to find something, that wouldn't stand in my way later on. I have done quite a bit reading on this subject, but I still don't have a clear picture, to what suits my needs, so I come to you, StackOverflow, to give me directions. I know you all must be wondering what I'm building, but I assure you, that it doesn't matter. I have heard of 12 factor app though, if you have any similar guidelines or what is, to suggest the please, go ahead. For the sake of keeping your answers as open as possible, I'm not gonna provide you my experience regarding anything written in this question. ^ Skippers, start here First off - the weights of the requirements are probably something like that (on a scale of 10): Security - 10 Speed - 5 Reliability (concurrency) - 7.5 Scalability - 10 Speed and concurrency are not a top priority, in the sense, that the program can be CPU intensive, and therefore slow, and only accept a not-that-high number of concurrent users, but both of these factors must be improvable by scaling the system Anyway, here are my questions: How many layers should the application have, so it would be future-proof and could best fulfill the aforementioned requirements? For now, what I have in mind is the most common version: Completely separated front end, that might be a web page or an MMI application or even both. Some middle-ware handling communication between the front and the back end. This is probably a server that communicates w/ the front end via HTTP. How the communication w/ the back end should be handled is probably dependent on the back end. The back end. Something that handles data through resources like DB and etc. and does various computations w/ the data. This, as the highest priority part of the software, must be easily spread to multiple computers later on and have no known security holes. I think ideally the middle-ware should send a request to a queue from where one of the back end processes takes this request, chops it up to smaller parts and buts these parts of the request back onto the same queue as the initial request, after what these parts will be then handled by other back end processes. Something *map-reduce*y, so to say. What frameworks, languages and etc. should these layers use? The technologies used here are not that important at this moment, you can ignore this part for now I've been pointed to node.js for this part. Do you guys know any better alternatives, or have any reasons why I should (not) use node.js for this particular job. I actually have no good idea, what to use for this job, there are too many options out there, so please direct me. This part (and the 2. one also, I think) depend a lot on the OS, so suggest any OSs alongside w/ the technologies/frameworks. Initially, all computers (or 1 for starters) hosting the back end are going to be virtual machines. Please do give suggestions to any part of the question, that you feel you have comprehensive knowledge and/or experience of. And also, point out if you feel that any part of the current set-up means an instant (or even distant) failure or if I missed a very important aspect to consider. I'm not looking for a definitive answer for how to achieve my goals, because there certainly isn't one, for I haven't provided you w/ all the required information. I'm just looking for recommendations and directions on what to look into. Also, bare in mind, that this isn't something that I have to get done quickly, to sell and let it be re-written by the new owner (which, I've been told for multiple times, is what I should aim for). I have all the time in the world and I really just want to learn doing something really high-end. Also, excuse me if my language isn't the best, I'm not a native. Anyway. Thanks in advance to anyone, who takes the time to help me out here. PS. When I do seem to come up w/ a good architecture/design for this project, I will certainly make it an open project and keep you guys up to date w/ it's development. As in what you could have told me earlier and etc. For obvious reasons the very same question got closed on SO, but could you guys still help me?.

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• Working Qt controls in a 3d environment

  - by Jay

  I need some advice from a Qt expert. The background: I have a 3D engine (ogre3d) working in concert with Qt. The 3D Content is displayed in a widget (using a custom OS window in the client area). I'm able to overlay arbitrary Qt widgets onto the 3d world using the widget render() method and a shared bitmap. This makes a great "heads up display". I can use the standard Qt style sheets and animation using this technique. My goal I'd like to go a step further and allow the user to move these rendered widgets using the mouse. I'd like some advice on the best way to implement this. Possible solutions: The widgets in the HUD are not part of the inheritance chain. I render them manually. They don't get events though. I could add them to the inheritance chain so they get events in the usual way. Then I would need to change them to render to my shared bitmap instead of to the operating system. I looked at this once but couldn't find enough information to implement it. Capture mouse events in the 3D display widget and EMIT them to child controls. I basically create my own event handling chain. Any suggestions on how to implement this? I'm also considering switching to Qt5. I'm not sure how that might affect this decision.

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• What do ptLineDist and relativeCCW do?

  - by Fasih Khatib

  I saw these methods in the Line2D Java Docs but did not understand what they do? Javadoc for ptLineDist says: Returns the distance from a point to this line. The distance measured is the distance between the specified point and the closest point on the infinitely-extended line defined by this Line2D. If the specified point intersects the line, this method returns 0.0 Doc for relativeCCW says: Returns an indicator of where the specified point (PX, PY) lies with respect to the line segment from (X1, Y1) to (X2, Y2). The return value can be either 1, -1, or 0 and indicates in which direction the specified line must pivot around its first endpoint, (X1, Y1), in order to point at the specified point (PX, PY). A return value of 1 indicates that the line segment must turn in the direction that takes the positive X axis towards the negative Y axis. In the default coordinate system used by Java 2D, this direction is counterclockwise. A return value of -1 indicates that the line segment must turn in the direction that takes the positive X axis towards the positive Y axis. In the default coordinate system, this direction is clockwise. A return value of 0 indicates that the point lies exactly on the line segment. Note that an indicator value of 0 is rare and not useful for determining colinearity because of floating point rounding issues. If the point is colinear with the line segment, but not between the endpoints, then the value will be -1 if the point lies "beyond (X1, Y1)" or 1 if the point lies "beyond (X2, Y2)".

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• How to gun shots sounds right in game development?

  - by G3tinmybelly

  So I am now trying to find sounds for my guns but when I grab a gun sound effect and play it in my game a lot of the sounds are either terrible sounding or have this horrible echoing effect because as a gun shoots sometimes the previous sound is playing still. public void shoot(float x, float y, float direction){ if(empty){ PlayHUD.message = "No more bullets!"; return; } if(reloading){ return; } if(System.currentTimeMillis() - lastShot < fireRate){ //AssetsLoader.lmgSound.stop(); return; } float dx = (float) (-13 * Math.cos(direction) + 75 * Math.sin(direction)); float dy = (float) (-14 * -Math.sin(direction) + 75 * Math.cos(direction)); float dx1 = (float) (-13 * Math.cos(direction) + 75 * Math.sin(direction)); float dy1 = (float) (-14 * -Math.sin(direction) + 75 * Math.cos(direction)); PlayState.effects.add(new MuzzleFlashEffect(x + dx1, y + dy1, (float) Math.toDegrees(-direction))); PlayState.projectiles.add(new Bullet(this, x + dx, y + dy, (float) (direction + (Math.toRadians(MathUtils.random(-accuracy, accuracy)))))); if(OptionState.soundOn){ AssetsLoader.lmgSound.play(OptionState.volume); } bulletsInClip--; lastShot = System.currentTimeMillis(); } Here is the code for where the sound plays. Every time this method is called the sound is called but it happens so often in this case that there is this terrible echoing. Any idea on how to fix this?

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• How do I find actors in an area on a poly-precise basis?

  - by Almo

  Ok, I've been asking various questions and getting some good answers, but I think I need to rethink my method, so I'll describe the problem. I have a player who has a big blue box in front of him. This box shows which KActors will be pushed when he pulls the trigger: Currently, the blue box spawns a descendant of Actor which checks collision to see which KActors are touching it: foreach Owner.TouchingActors(class'DynamicSMActor', DynamicActorItt) { // do stuff } The problem is, if you check for touching between Actors and KActors, it looks like it does a plain axis-aligned bounding-box collision. The power will push the box on the lower right, when it's clear it's not touching the blue box. How should I do this properly? I just need a way to find out which KActors are touching that area, on a poly-by-poly level. These collisions are only done with rectangular boxes and simple sphere collision; we are aware of the potential for performance issues with complex objects and poly-collision. I've tried making the collision checker a KActor, but it doesn't report any TouchingActors. This issue is causing us trouble in a lot of other places as well. So solving this problem is a core issue in our game.

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• What is a good way to refactor a large, terribly written code base by myself? [closed]

  - by AgentKC

  Possible Duplicate: Techniques to re-factor garbage and maintain sanity? I have a fairly large PHP code base that I have been writing for the past 3 years. The problem is, I wrote this code when I was a terrible programmer and now it's tens of thousands of lines of conditionals and random MySQL queries everywhere. As you can imagine, there are a ton of bugs and they are extremely hard to find and fix. So I would like a good method to refactor this code so that it is much more manageable. The source code is quite bad; I did not even use classes or functions when I originally wrote it. At this point, I am considering rewriting the whole thing. I am the only developer and my time is pretty limited. I would like to get this done as quickly as possible, so I can get back to writing new features. Since rewriting the code would take a long time, I am looking for some methods that I can use to clean up the code as quickly as possible without leaving more bad architecture that will come back to haunt me later. So this is the basic question: What is a good way for a single developer to take a fairly large code base that has no architecture and refactor it into something with reasonable architecture that is not a nightmare to maintain and expand?

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• Android Bitmap: Collision Detecting

  - by Aekasitt Guruvanich

  I am writing an Android game right now and I would need some help in the collision of the Pawns on screen. I figured I could run a for loop on the Player class with all Pawn objects on the screen checking whether or not Width*Height intersects with each other, but is there a more efficient way to do this? And if you do it this way, many of the transparent pixel inside the rectangular area will also be considered as collision as well. Is there a way to check for collision between Bitmap on a Canvas that disregard transparent pixels? The class for player is below and the Pawn class uses the same method of display. Class Player { private Resources res; // Used for referencing Bitmap from predefined location private Bounds bounds; // Class that holds the boundary of the screen private Bitmap image; private float x, y; private Matrix position; private int width, height; private float velocity_x, velocity_y; public Player (Resources resources, Bounds boundary) { res = resources; bounds = boundary; image = BitmapFactory.decodeResource(res, R.drawable.player); width = image.getWidth(); height = image.getHeight(); position = new Matrix(); x = bounds.xMax / 2; // Initially puts the Player in the middle of screen y = bounds.yMax / 2; position.preTranslate(x,y); } public void draw(Canvas canvas) { canvas.drawBitmap(image, position, null); } }

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• Change spacing of icons in Indicator Applet Complete, preferably by editing a config file?

  - by PeaTearGriffin

  Changing icon spacing within Application Indicator Complete. If at all possible, I'd like to space them with about 1-3px between each one. https://launchpad.net/indicator-applet [Website] I'm using 12.04, and in GNOME Classic (No Effects). I'm working from a netbook (1024x600), and am trying to fit everything into one panel for the sake of screen conservation. Ironically, my netbook is often without reliable net access, and so a way to simply edit a config file or the like would be ideal, as opposed to downloading patches, modified packages, etc., but anything would be helpful. Even pointing me in the direction of how to start rebuilding the indicator to meet my needs (if need-be) would be welcome. Does anyone know of a method that would serve my purpose? EDIT: I've downloaded v0.4.93 from the site mentioned above, and took a look inside the archive. Couldn't find anything clearly alluding to object placement/size and such. Maybe just a pointer on where to find those params would do? EDIT 2: Some more info on my WM/DE: I'm pretty sure GNOME classic is gtk2 not gtk3, and equally sure my windows manager is metacity, as opposed to compiz. "equally sure" meaning i could be horribly wrong, but when I edit the metacity css file for my theme (which ive switched to "Adawaita"), it takes effect after logout/login. My inability to modify the spacing persists. Im gonna see if i can contact someone involved in its dev to get their input, will post results here if fruitful.

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• Interfaces on an abstract class

  - by insta

  My coworker and I have different opinions on the relationship between base classes and interfaces. I'm of the belief that a class should not implement an interface unless that class can be used when an implementation of the interface is required. In other words, I like to see code like this: interface IFooWorker { void Work(); } abstract class BaseWorker { ... base class behaviors ... public abstract void Work() { } protected string CleanData(string data) { ... } } class DbWorker : BaseWorker, IFooWorker { public void Work() { Repository.AddCleanData(base.CleanData(UI.GetDirtyData())); } } The DbWorker is what gets the IFooWorker interface, because it is an instantiatable implementation of the interface. It completely fulfills the contract. My coworker prefers the nearly identical: interface IFooWorker { void Work(); } abstract class BaseWorker : IFooWorker { ... base class behaviors ... public abstract void Work() { } protected string CleanData(string data) { ... } } class DbWorker : BaseWorker { public void Work() { Repository.AddCleanData(base.CleanData(UI.GetDirtyData())); } } Where the base class gets the interface, and by virtue of this all inheritors of the base class are of that interface as well. This bugs me but I can't come up with concrete reasons why, outside of "the base class cannot stand on its own as an implementation of the interface". What are the pros & cons of his method vs. mine, and why should one be used over another?

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• Repository query conditions, dependencies and DRY

  - by vFragosop

  To keep it simple, let's suppose an application which has Accounts and Users. Each account may have any number of users. There's also 3 consumers of UserRepository: An admin interface which may list all users Public front-end which may list all users An account authenticated API which should only list it's own users Assuming UserRepository is something like this: class UsersRepository extends DatabaseAbstraction { private function query() { return $this->database()->select('users.*'); } public function getAll() { return $this->query()->exec(); } // IMPORTANT: // Tons of other methods for searching, filtering, // joining of other tables, ordering and such... } Keeping in mind the comment above, and the necessity to abstract user querying conditions, How should I handle querying of users filtering by account_id? I can picture three possible roads: 1. Should I create an AccountUsersRepository? class AccountUsersRepository extends UserRepository { public function __construct(Account $account) { $this->account = $account; } private function query() { return parent::query() ->where('account_id', '=', $this->account->id); } } This has the advantage of reducing the duplication of UsersRepository methods, but doesn't quite fit into anything I've read about DDD so far (I'm rookie by the way) 2. Should I put it as a method on AccountsRepository? class AccountsRepository extends DatabaseAbstraction { public function getAccountUsers(Account $account) { return $this->database() ->select('users.*') ->where('account_id', '=', $account->id) ->exec(); } } This requires the duplication of all UserRepository methods and may need another UserQuery layer, that implements those querying logic on chainable way. 3. Should I query UserRepository from within my account entity? class Account extends Entity { public function getUsers() { return UserRepository::findByAccountId($this->id); } } This feels more like an aggregate root for me, but introduces dependency of UserRepository on Account entity, which may violate a few principles. 4. Or am I missing the point completely? Maybe there's an even better solution? Footnotes: Besides permissions being a Service concern, in my understanding, they shouldn't implement SQL query but leave that to repositories since those may not even be SQL driven.

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• using NetBeans for rotate a figure in a label [migrated]

  - by user134812

  I was reading this post: http://forums.netbeans.org/post-8864.html and what I have done so far is to make a jFrame in NetBeans, on it I have drawn a jPanel and inisde the panel I have drawn a jLabel on it and use the icon property to put an image on it; until now all is so far so good. I would like to make a program that everytime I click on the figure it rotates it to the right. Actually I have found the following code: public class RotateImage extends JPanel{ // Declare an Image object for us to use. Image image; // Create a constructor method public RotateImage(){ super(); // Load an image to play with. image = Toolkit.getDefaultToolkit().getImage("Duke_Blocks.gif"); } public void paintComponent(Graphics g){ Graphics2D g2d=(Graphics2D)g; // Create a Java2D version of g. g2d.translate(170, 0); // Translate the center of our coordinates. g2d.rotate(1); // Rotate the image by 1 radian. g2d.drawImage(image, 0, 0, 200, 200, this); } but for what I see this code is for making the panel and other components from scratch, for my purposes it is not so good because I need to put several figures on my jFrame. Could somebody can give me a hint how to do this?

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• How to fundamentally approach creating a 'financial planner' application?

  - by Anonymous -

  I want to create a financial planning application (for personal use), for which the overall functionality will be this: User (me..) can create different 'scenarios'. Each scenario is configured with different incomings/outgoings. Scenarios can be 'explored' in a calendar format with projections taking into account tax, interest (on both debt and savings) and so on and so forth. My problem lies in how to fundamentally approach the project. I've considered: When creating incomings/outgoings for a script to apply them to each day in a 'days' table of a database, acting as a method of caching. This means that if I wanted to look at January 14th, 2074 there aren't thousands of cycles of calculations to run through and the result can just be pulled. Do each calculation dynamically, but again, I'm finding it hard to visuallize how I would handle different tax allowances (I'm based in the UK by the way), payrises and 'changes' to my incomings/outgoings. I've sat on this for a couple of days and am struggling to come up with an elegant approach to my problem. There may well be software out there that does what I'm looking to do (in fact I'm sure it is) but I would like to develop this myself for learning purposes, to be able to add it to my personal life 'toolset' and to allow me to expand on it in the future. Many thanks to all who have any input on my dilemna.

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• Approaches for a clickable map of nations (such as a Risk game) with Spritekit

  - by Vukovitch

  I would like to create a political map where each country is clickable by tapping but I'm not sure the best way to determine which nation was selected. Imagine Risk where each country can be individually clicked to bring up additional information. My current approach is to make a sprite for each nation where every image is the size of the screen The images are mostly transparent except for the country, that way when all of the images are displayed the countries are in the correct place relative to one another. To determine if a click occurs on an individual country I look to see if the tapped location is a non transparent pixel and check that the sprite's name is one of the countries. Additionally the nation needs to glow or something when tapped as an indicator, however my current solution is yet another sprite that is displayed. This seems like a terrible approach and I was wondering what other solutions might achieve the same results. I'm pretty new to SpriteKit so I'm not entirely sure. The other idea I had was creating a single texture where each country is a different shade of gray, then when I get the tap location I do a lookup on the color at that location and get the corresponding country. However, I'm not sure how to create a hilight or glowing country effect with that method.

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• How to work with processes?

  - by Viesturs

  I have seen similar questions here, but I didn't get my answer. Maybe it's because I am new to all this and just don't understand. I want my app to work mostly as an indicator. And if user would start it again it would check if it is already running, if it is then give all the input data to that process and quit. So first I need to check if it is running. I saw the answer where you can make a file witch when the program starts and then check if it exists... But what if someone would delete it? Can't I just ask the OS if there is process named "myApp" or something? The next thing I don't really get is how to communicate with the process. How do I give it the input data and what is it going to do with it? Does it work just like starting a new app, through the main() method? I am trying to create this using Quickly. So it would be nice if you can give me some python examples or link to something like that.

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• Is there a PROPRIETARY driver (NVIDIA or ATI) that actually works with 12.10?

  - by DS13

  NOTE: I see many similar topics on this, but I've tried all their suggestions, and nothing has worked. THE MAIN DIFFERENCE SEEMS TO BE: I always get a black screen with a blinking cursor, while others seem to get through the boot-up and see distorted graphics or just their wallpaper. ISSUE: I do a clean install of Ubuntu 12.10. Boots fine with the “nouveau” graphics driver – graphics (even just menus) are very slow, choppy, and distorted. The three other driver options in Ubuntu (official NVIDIA drivers), all result in a variation of the black screen on boot up. There will be NO access to a command line/GUI in anyway what-so-ever (tried every option recommended out there, but the system is unusable at this stage). I can only reinstall, and try different drivers…and I only ever get one shot at it. QUESTIONS: -Does anyone know of a PROPRIETARY driver that will actually work on 12.10 with a NVIDIA or ATI card? -Should I just buy a newer graphics card to put in as a replacement? MORE INFO: This is my second computer, and I’m just trying to get a working install of Ubuntu on it. I don’t want to put much money into it, as I have seen Ubuntu run great on much older/less capable machines. I’ve got a decent'ish Core2Duo Intel processor (2.13Ghz), 2GB of RAM, 320GB hard drive, 32-bit architecture, and there is no other O/S installed. It appears as if the graphics card (NVIDIA Geforce 7350 LE) is holding me back. TRIED SO FAR: -all drivers available in Ubuntu *all fail -manual install of some different NVIDIA drivers *all fail -also tried installing the generic kernel, Nvidia driver doesn't work in 12.10 *no difference -tried installing 12.04 *same results -every method suggested to at least get a command line after switching to a NVIDIA driver *all fail -UPDATE- Re-tried everything above with a new NVIDIA Geforce 210...same results for everything. -UPDATE #2- Re-tried everything above with a new AMD Radeon HD 6450...installed the proprietary driver from Ubuntu's "Software Sources" menu...EVERYTHING NOW WORKS. See "answer" below for summary.

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• Is it reasonable to null guard every single dereferenced pointer?

  - by evadeflow

  At a new job, I've been getting flagged in code reviews for code like this: PowerManager::PowerManager(IMsgSender* msgSender) : msgSender_(msgSender) { } void PowerManager::SignalShutdown() { msgSender_->sendMsg("shutdown()"); } I'm told that last method should read: void PowerManager::SignalShutdown() { if (msgSender_) { msgSender_->sendMsg("shutdown()"); } } i.e., I must put a NULL guard around the msgSender_ variable, even though it is a private data member. It's difficult for me to restrain myself from using expletives to describe how I feel about this piece of 'wisdom'. When I ask for an explanation, I get a litany of horror stories about how some junior programmer, some-year, got confused about how a class was supposed to work and accidentally deleted a member he shouldn't have (and set it to NULL afterwards, apparently), and things blew up in the field right after a product release, and we've "learned the hard way, trust us" that it's better to just NULL check everything. To me, this feels like cargo cult programming, plain and simple. A few well-meaning colleagues are earnestly trying to help me 'get it' and see how this will help me write more robust code, but... I can't help feeling like they're the ones who don't get it. Is it reasonable for a coding standard to require that every single pointer dereferenced in a function be checked for NULL first—even private data members? (Note: To give some context, we make a consumer electronics device, not an air traffic control system or some other 'failure-equals-people-die' product.) EDIT: In the above example, the msgSender_ collaborator isn't optional. If it's ever NULL, it indicates a bug. The only reason it is passed into the constructor is so PowerManager can be tested with a mock IMsgSender subclass.

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• Create new terminal commands

  - by sleort

  I recently installed eclipse the manual way. Extracting the file, setting up eclipse.desktop etc. It all works flawlessly. I also know it is possible to install eclipsee using sudo apt-get install eclipse-platform. If I use this method I can use the command eclipse in the terminal, and the program will start. Now the manual way I used does not enable the eclipse-command in the terminal. Instead if I use eclipse-command it asks me to install eclipse from the Softwarecenter (sudo apt-get install eclipse-platform). I wondered if there was some way of setting up a command like this to start eclipse? If so, can I do it for other programs like Apache-Maven mvn-command? I don't want to use "aliases" because I cannot setup and eclipse alias, when "eclipse" is listed in the apt repository. It seems as if only if I install the eclipse from apt-get install I can start eclipse from a single command in the terminal. I appreciate any help, and thanks in advance!

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• Could a singleton type replace static methods and classes?

  - by MKO

  In C# Static methods has long served a purpose allowing us to call them without instantiating classes. Only in later year have we became more aware of the problems of using static methods and classes. They can’t use interfaces They can’t use inheritance They are hard to test because you can’t make mocks and stubs Is there a better way ? Obviously we need to be able to access library methods without instantiated classes all the time otherwise our code would become pretty cluttered One possibly solution is to use a new keyword for an old concept: the singleton. Singleton’s are global instances of a class, since they are instances we can use them as we would normal classes. In order to make their use nice and practical we'd need some syntactic sugar however Say that the Math class would be of type singleton instead of an actual class. The actual class containing all the default methods for the Math singleton is DefaultMath, which implements the interface IMath. The singleton would be declared as singleton Math : IMath { public Math { this = new DefaultMath(); } } If we wanted to substitute our own class for all math operations we could make a new class MyMath that inherits DefaultMath, or we could just inherit from the interface IMath and create a whole new Class. To make our class the active Math class, you'd do a simple assignment Math = new MyMath(); and voilá! the next time we call Math.Floor it will call your method. Note that for a normal singleton we'd have to write something like Math.Instance.Floor but the compiler eliminates the need for the Instance property Another idea would be to be able to define a singletons as Lazy so they get instantiated only when they're first called, like lazy singleton Math : IMath What do you think, would it have been a better solution that static methods and classes? Is there any problems with this approach?

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• Tile sizes in 2D games

  - by Ephismen

  While developing a small game using tile-mapping method a question came to my mind: I would develop the game on Windows but wouldn't exclude adapting it to another platform. What size(in pixels) would you recommend using for creating the tiles of a tile-mapped game(ie: RPG) with the following requirements? Have an acceptable level of detail without having too many tiles. Having a decent map size. Allow adaptation of the game on a handheld(ie: PSP), smartphone or a computer without too much loss of detail or slowdowns. Allow more or less important zoom-in / zoom-out. Have a resolution of tile that permits either pixel-perfect collision or block-collision. Anything from a good explanation to a game example is useful as long as it can fit the requirements. This question may seem a bit simplistic, but I noticed that many Indies game developer were using inappropriate scales scenery. Also sorry for the poor syntax and the lack of vocabulary of my question, being a non-native English speaker doesn't help when talking about computers programming.

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• Storing a pass-by-reference parameter as a pointer - Bad practice?

  - by Karl Nicoll

  I recently came across the following pattern in an API I've been forced to use: class SomeObject { public: // Constructor. SomeObject(bool copy = false); // Set a value. void SetValue(const ComplexType &value); private: bool m_copy; ComplexType *m_pComplexType; ComplexType m_complexType; }; // ------------------------------------------------------------ SomeObject::SomeObject(bool copy) : m_copy(copy) { } // ------------------------------------------------------------ void SomeObject::SetValue(const ComplexType &value) { if (m_copy) m_complexType.assign(value); else m_pComplexType = const_cast<ComplexType *>(&value); } The background behind this pattern is that it is used to hold data prior to it being encoded and sent to a TCP socket. The copy weirdness is designed to make the class SomeObject efficient by only holding a pointer to the object until it needs to be encoded, but also provide the option to copy values if the lifetime of the SomeObject exceeds the lifetime of a ComplexType. However, consider the following: SomeObject SomeFunction() { ComplexType complexTypeInstance(1); // Create an instance of ComplexType. SomeObject encodeHelper; encodeHelper.SetValue(complexTypeInstance); // Okay. return encodeHelper; // Uh oh! complexTypeInstance has been destroyed, and // now encoding will venture into the realm of undefined // behaviour! } I tripped over this because I used the default constructor, and this resulted in messages being encoded as blank (through a fluke of undefined behaviour). It took an absolute age to pinpoint the cause! Anyway, is this a standard pattern for something like this? Are there any advantages to doing it this way vs overloading the SetValue method to accept a pointer that I'm missing? Thanks!

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• Why does printf report an error on all but three (ASCII-range) Unicode Codepoints, yet is fine with all others?

  - by fred.bear

  The 'printf' I refer to is the standard-issue "program" (not the built-in): /usr/bin/printf I was testing printf out as a viable method of convert a Unicode Codepoint Hex-literal into its Unicoder character representation, I was looking good, and seemed flawless..(btw. the built-in printf can't do this at all (I think)... I then thought to test it at the lower extreme end of the code-spectrum, and it failed with an avalanche of errors.. All in the ASCII range (= 7 bits) The strangest thing was that 3 value printed normally; they are: $ \u0024 @ \u0040 ` \u0060 I'd like to know what is going on here. The ASCII character-set is most definitely part of the Unicode Code-point sequence.... I am puzzled, and still without a good way to bash script this particular converion.. Suggestions are welcome. To be entertained by that same avalanche of errors, paste the following code into a terminal... # Here is one of the error messages # /usr/bin/printf: invalid universal character name \u0041 # ...for them all, run the following script ( for nib1 in {0..9} {A..F}; do for nib0 in {0..9} {A..F}; do [[ $nib1 < A ]] && nl="\n" || nl=" " $(type -P printf) "\u00$nib1$nib0$nl" done done echo )

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• Will Ubuntu Live CD move MFT to resize NTFS volumes?

  - by irwazr

  I have a feeling some will consider this a duplicate, but please hear me out. I've been reading tons of questions and threads around this but have never really found an answer for this specifically. I want to shrink my NTFS partition to make room for a Ubuntu install, so I can dual boot them. However when shrinking the NTFS volume in Windows disk management, it will only go so far as the MFT is sitting near the end of the volume. I've read plenty of posts about why it does this, and how difficult/dangerous it is to move the MFT etc. I've also read that Perfect Disk can apparently do it under it's trial period, but I remain cautious to try this method. I was wondering however if the disk partitioning utility included in the Ubuntu install wizard handles the moving of the MFT when dragging the partition boundaries. It all seems too simple that you simply tell it the new size you want it to be. Would it tell me if it couldn't resize by the amount you requested if the MFT was an issue, or move it for you if it were able. I'm concerned it might corrupt the MFT and the volume, even though I doubt the install wizard would be so daft. So what exactly is the deal with the partition resizing tool in the Ubuntu install wizard? Will it safely resize my NTFS volume despite the location of my MFT? Thanks in advance.

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• HTTP PHP Authentication and Android

  - by edc598

  I am working on a website for which I hope to have an application for as well. Because of this, I am creating PHP API's which will go into my Database and serve specific data based on the method/function called. I want to protect these API's from misuse however, and I plan on implementing Authentication Digest to do so. However one of the OS's I want to support is Android. And I know that a malicious user would be able to reverse engineer the Android app and figure out my authentication scheme. I am left wondering: 1. Is there a better way to protect these API's from misuse? 2. Is there a way to prevent a malicious user from reverse engineering the app and potentially seeing the source code for it, enabling them to see my authentication scheme? 3. If none of these are preventable, then is my only option to have a Username/Password cred specifically for the Android app, and when eventually hacked, change the creds and issue an update for the app? I apologize if this is not the place to post such a question. Still pretty new to StackOverflow. Thanks in advance for any insight, it would be quite helpful.

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• F# Objects &ndash; Part 3 &ndash; it&rsquo;s time to overload&hellip;

  - by MarkPearl

  Okay, some basic examples of overloading in F# Overloading Constructors Assume you have a F# object called person… type Person (firstname : string, lastname : string) = member v.Fullname = firstname + " " + lastname   This only has one constructor. To add additional constructors to the object by explicitly declaring them using the method member new. type Person (firstname : string, lastname : string) = new () = Person("Unknown", "Unknown") member v.Fullname = firstname + " " + lastname   In the code above I added another constructor to the Person object that takes no parameters and then refers to the primary constructor. Using the same technique in the code below I have created another constructor that accepts only the firstname as a parameter to create an object. type Person (firstname : string, lastname : string) = new () = Person("Unknown", "Unknown") new (firstname : string) = Person(firstname, "Unknown") member v.Fullname = firstname + " " + lastname   Overloading Operators So, you can overload operators of objects in F# as well… let’s look at example code… type Person(name : string) = member v.name = name static member (+) (person1 : Person , person2 : Person) = Person(person1.name + " " + person2.name)   In the code above we have overloaded the “+” operator. Whenever we add to Person objects together, it will now create a new object with the combined names…

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