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  • Alternatives to multiple inheritance for my architecture (NPCs in a Realtime Strategy game)?

    - by Brettetete
    Coding isn't that hard actually. The hard part is to write code that makes sense, is readable and understandable. So I want to get a better developer and create some solid architecture. So I want to do create an architecture for NPCs in a video-game. It is a Realtime Strategy game like Starcraft, Age of Empires, Command & Conquers, etc etc.. So I'll have different kinds of NPCs. A NPC can have one to many abilities (methods) of these: Build(), Farm() and Attack(). Examples: Worker can Build() and Farm() Warrior can Attack() Citizen can Build(), Farm() and Attack() Fisherman can Farm() and Attack() I hope everything is clear so far. So now I do have my NPC Types and their abilities. But lets come to the technical / programmatical aspect. What would be a good programmatic architecture for my different kinds of NPCs? Okay I could have a base class. Actually I think this is a good way to stick with the DRY principle. So I can have methods like WalkTo(x,y) in my base class since every NPC will be able to move. But now lets come to the real problem. Where do I implement my abilities? (remember: Build(), Farm() and Attack()) Since the abilities will consists of the same logic it would be annoying / break DRY principle to implement them for each NPC (Worker,Warrior, ..). Okay I could implement the abilities within the base class. This would require some kind of logic that verifies if a NPC can use ability X. IsBuilder, CanBuild, .. I think it is clear what I want to express. But I don't feel very well with this idea. This sounds like a bloated base class with too much functionality. I do use C# as programming language. So multiple inheritance isn't an opinion here. Means: Having extra base classes like Fisherman : Farmer, Attacker won't work.

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  • Naming your unit tests

    - by kerry
    When you create a test for your class, what kind of naming convention do you use for the tests? How thorough are your tests? I have lately switched from the conventional camel case test names to lower case letters with underscores. I have found this increases the readability and causes me to write better tests. A simple utility class: public class ArrayUtils { public static T[] gimmeASlice(T[] anArray, Integer start, Integer end) { // implementation (feeling lazy today) } } I have seen some people who would write a test like this: public class ArrayUtilsTest { @Test public void testGimmeASliceMethod() { // do some tests } } A more thorough and readable test would be: public class ArrayUtilsTest { @Test public void gimmeASlice_returns_appropriate_slice() { // ... } @Test public void gimmeASlice_throws_NullPointerException_when_passed_null() { // ... } @Test public void gimmeASlice_returns_end_of_array_when_slice_is_partly_out_of_bounds() { // ... } @Test public void gimmeASlice_returns_empty_array_when_slice_is_completely_out_of_bounds() { // ... } } Looking at this test, you have no doubt what the method is supposed to do. And, when one fails, you will know exactly what the issue is.

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  • BeanInfo Editor in NetBeans Rocks

    - by Geertjan
    Impressed by a cool feature I didn't know about. If you have some JavaBean, like my Event class below, you can right-click it and choose "BeanInfo Editor": Now, as you can see above, I don't have a BeanInfo class. So I am now asked whether the IDE should create one for me. So I say OK and then I have a new BeanInfo class, generated from my Event class, as well as a multiview editor for visually editing the BeanInfo class: Thanks Eric and Nicklas from Artificial Solutions in Stockholm for pointing this out to me today. It comes in very handy in NetBeans Platform applications when you're working with a BeanNode and want to customize the display of your properties.

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  • Oracle R Distribution 2-13.2 Update Available

    - by Sherry LaMonica
    Oracle has released an update to the Oracle R Distribution, an Oracle-supported distribution of open source R. Oracle R Distribution 2-13.2 now contains the ability to dynamically link the following libraries on both Windows and Linux: The Intel Math Kernel Library (MKL) on Intel chips The AMD Core Math Library (ACML) on AMD chips To take advantage of the performance enhancements provided by Intel MKL or AMD ACML in Oracle R Distribution, simply add the MKL or ACML shared library directory to the LD_LIBRARY_PATH system environment variable. This automatically enables MKL or ACML to make use of all available processors, vastly speeding up linear algebra computations and eliminating the need to recompile R.  Even on a single core, the optimized algorithms in the Intel MKL libraries are faster than using R's standard BLAS library. Open-source R is linked to NetLib's BLAS libraries, but they are not multi-threaded and only use one core. While R's internal BLAS are efficient for most computations, it's possible to recompile R to link to a different, multi-threaded BLAS library to improve performance on eligible calculations. Compiling and linking to R yourself can be involved, but for many, the significantly improved calculation speed justifies the effort. Oracle R Distribution notably simplifies the process of using external math libraries by enabling R to auto-load MKL or ACML. For R commands that don't link to BLAS code, taking advantage of database parallelism using embedded R execution in Oracle R Enterprise is the route to improved performance. For more information about rebuilding R with different BLAS libraries, see the linear algebra section in the R Installation and Administration manual. As always, the Oracle R Distribution is available as a free download to anyone. Questions and comments are welcome on the Oracle R Forum.

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  • Navigation in a #WP7 application with MVVM Light

    - by Laurent Bugnion
    In MVVM applications, it can be a bit of a challenge to send instructions to the view (for example a page) from a viewmodel. Thankfully, we have good tools at our disposal to help with that. In his excellent series “MVVM Light Toolkit soup to nuts”, Jesse Liberty proposes one approach using the MVVM Light messaging infrastructure. While this works fine, I would like to show here another approach using what I call a “view service”, i.e. an abstracted service that is invoked from the viewmodel, and implemented on the view. Multiple kinds of view services In fact, I use view services quite often, and even started standardizing them for the Windows Phone 7 applications I work on. If there is interest, I will be happy to show other such view services, for example Animation services, responsible to start/stop animations on the view. Dialog service, in charge of displaying messages to the user and gathering feedback. Navigation service, in charge of navigating to a given page directly from the viewmodel. In this article, I will concentrate on the navigation service. The INavigationService interface In most WP7 apps, the navigation service is used in quite a straightforward way. We want to: Navigate to a given URI. Go back. Be notified when a navigation is taking place, and be able to cancel. The INavigationService interface is quite simple indeed: public interface INavigationService { event NavigatingCancelEventHandler Navigating; void NavigateTo(Uri pageUri); void GoBack(); } Obviously, this interface can be extended if necessary, but in most of the apps I worked on, I found that this covers my needs. The NavigationService class It is possible to nicely pack the navigation service into its own class. To do this, we need to remember that all the PhoneApplicationPage instances use the same instance of the navigation service, exposed through their NavigationService property. In fact, in a WP7 application, it is the main frame (RootFrame, of type PhoneApplicationFrame) that is responsible for this task. So, our implementation of the NavigationService class can leverage this. First the class will grab the PhoneApplicationFrame and store a reference to it. Also, it registers a handler for the Navigating event, and forwards the event to the listening viewmodels (if any). Then, the NavigateTo and the GoBack methods are implemented. They are quite simple, because they are in fact just a gateway to the PhoneApplicationFrame. The whole class is as follows: public class NavigationService : INavigationService { private PhoneApplicationFrame _mainFrame; public event NavigatingCancelEventHandler Navigating; public void NavigateTo(Uri pageUri) { if (EnsureMainFrame()) { _mainFrame.Navigate(pageUri); } } public void GoBack() { if (EnsureMainFrame() && _mainFrame.CanGoBack) { _mainFrame.GoBack(); } } private bool EnsureMainFrame() { if (_mainFrame != null) { return true; } _mainFrame = Application.Current.RootVisual as PhoneApplicationFrame; if (_mainFrame != null) { // Could be null if the app runs inside a design tool _mainFrame.Navigating += (s, e) => { if (Navigating != null) { Navigating(s, e); } }; return true; } return false; } } Exposing URIs I find that it is a good practice to expose each page’s URI as a constant. In MVVM Light applications, a good place to do that is the ViewModelLocator, which already acts like a central point of setup for the views and their viewmodels. Note that in some cases, it is necessary to expose the URL as a string, for instance when a query string needs to be passed to the view. So for example we could have: public static readonly Uri MainPageUri = new Uri("/MainPage.xaml", UriKind.Relative); public const string AnotherPageUrl = "/AnotherPage.xaml?param1={0}&param2={1}"; Creating and using the NavigationService Normally, we only need one instance of the NavigationService class. In cases where you use an IOC container, it is easy to simply register a singleton instance. For example, I am using a modified version of a super simple IOC container, and so I can register the navigation service as follows: SimpleIoc.Register<INavigationService, NavigationService>(); Then, it can be resolved where needed with: SimpleIoc.Resolve<INavigationService>(); Or (more frequently), I simply declare a parameter on the viewmodel constructor of type INavigationService and let the IOC container do its magic and inject the instance of the NavigationService when the viewmodel is created. On supported platforms (for example Silverlight 4), it is also possible to use MEF. Or, of course, we can simply instantiate the NavigationService in the ViewModelLocator, and pass this instance as a parameter of the viewmodels’ constructor, injected as a property, etc… Once the instance has been passed to the viewmodel, it can be used, for example with: NavigationService.NavigateTo(ViewModelLocator.ComparisonPageUri); Testing Thanks to the INavigationService interface, navigation can be mocked and tested when the viewmodel is put under unit test. Simply implement and inject a mock class, and assert that the methods are called as they should by the viewmodel. Conclusion As usual, there are multiple ways to code a solution answering your needs. I find that view services are a really neat way to delegate view-specific responsibilities such as animation, dialogs and of course navigation to other classes through an abstracted interface. In some cases, such as the NavigationService class exposed here, it is even possible to standardize the implementation and pack it in a class library for reuse. I hope that this sample is useful! Happy coding. Laurent   Laurent Bugnion (GalaSoft) Subscribe | Twitter | Facebook | Flickr | LinkedIn

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  • How can I access bitmaps created in another activity?

    - by user22241
    I am currently loading my game bitmaps when the user presses 'start' in my animated splash screen activity (the first / launch activity) and the app progresses from my this activity to the main game activity, This is causing choppy animation in the splashscreen while it loads/creates the bitmaps for the new activity. I've been told that I should load all my bitmaps in one go at the very beginning. However, I can't work out how to do this - could anyone please point me in the right direction? I have 2 activities, a splash screen and the main game. Each consist of a class that extends activity and a class that extends SurfaceView (with an inner class for the rendering / logic updating). So, for example at the moment I am creating my bitmaps in the constructor of my SurfaceView class like so: public class OptionsScreen extends SurfaceView implements SurfaceHolder.Callback { //Create variables here public OptionsScreen(Context context) { Create bitmaps here } public void intialise(){ //This method is called from onCreate() of corresponding application context // Create scaled bitmaps here (from bitmaps previously created) }

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  • PHP OOP: Am i following right way?

    - by sineverba
    I'm learning OOP (PHP). I've realized my own CRUD Class, that performs some kind of queries SQL. Btw, a Gasoline asked us to realize a smart, simple web-app where he can update prices of his gasoline (gasoline, diesel, lpg) and via an API i could recall them and display in his site. So, I did create a new Class Gasoline but it perform some methods of CRUD Class public function getPrezzoBenzina($id) { $prezzo_benzina = $this->distributore->sql('SELECT prezzo_benzina FROM prezzi WHERE id = '.$id); return $prezzo_benzina } And so on (code is pseudocode, just to explain). I could perform all my code only with help of Crud Class... without necessity of Class Gasoline. So, what I'm missing about OOP? Where am I wrong?

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  • Error loading libGL.so.1

    - by jdp407
    When attempting to run various pieces of software (notably Steam and Yenka), I have come across an error similar to this: enter code here error while loading shared libraries: libGL.so.1: cannot open shared object file: No such file or directory I'm running a 64 bit system, with an NVidia Optimus card (I dual boot for certain windows only software that requires a dedicated graphics card). I have bumblebee installed, and I am using the nvidia-current driver, rather that one downloaded from NVidia, as recommended. The library (libGL.so.1) is not present in the top directory of /usr/lib, however it is present in /usr/lib32/nvidia-current, as a softlink to /usr/lib32/nvidia-current/libGL.so.304.64. A section of the output from ldconfig -p: libGL.so.1 (libc6,x86-64, OS ABI: Linux 2.4.20) => /usr/lib/x86_64-linux-gnu/mesa/libGL.so.1 libGL.so (libc6,x86-64, OS ABI: Linux 2.4.20) => /usr/lib/x86_64-linux-gnu/libGL.so libGL.so (libc6,x86-64, OS ABI: Linux 2.4.20) => /usr/lib/x86_64-linux-gnu/mesa/libGL.so Obviously a library with that name is being loaded, but they are located in /usr/lib/x86_64-linux-gnu, however installed software doesn't seem to able to 'see' it. For Steam, running it with optirun causes it to work, but this is not the case for Yenka. I assume that optirun causes the library stored in /usr/lib32/nvidia-current to be used, which allows Steam to run, so I can't understant why Yenka won't run. Can anyone explain why software can't see the normal mesa library, and why Yenka refuses to run with the nvidia-current library?

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  • Does a code inherit GNU GPL if it just link to GPL librrary?

    - by user14284
    Sorry for bad English. Suppose there is a library xxx under GNU GPL, that provide a function yyy. Suppose my code links to the library and use this function. Does my code inherit GPL license? IANAL, but my thoughts are conflicting: On other hand, my code is derivative from the library, so it should inherit GPL. On other hand, my code just use link to the xxx. Maybe there are other libraries, that has the same interface (particularly, they provide yyy function with same functionality, but different implementation). My code may link to any. My code really doesn't directly derived from xxx, it just use its interface. So, my code shouldn't inherit GPL. I'm confused. ADDED. The question is absolutely abstract. I don't mean any concrete GPL library.

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  • How to configure path or set environment variables for installation?

    - by Orr22
    I'm aiming to install APE in Ubuntu 14.04 LTS, a simple code for pseudopotential generation. I'm having this error message while running ./configure: checking for gsl-config... no checking for GSL - version >= 1.0... no *** The gsl-config script installed by GSL could not be found *** If GSL was installed in PREFIX, make sure PREFIX/bin is in *** your path, or set the GSL_CONFIG environment variable to the *** full path to gsl-config. configure: error: could not find required gsl library I checked and I have the GSL already installed: :~/Programas/ape-2.2.0$ dpkg -l | grep gsl ii libgsl0ldbl 1.16+dfsg-1ubuntu1 i386 GNU Scientific Library (GSL) -- library package So I have the library but the program installation isn't finding it. Any help? Thanks in advance

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  • Homebrew build with different arch?

    - by StasM
    I tried to install mysql-connector-c recipe via homebrew, and it builds just fine, but produces x86_64 library: $file ~/brew/lib/libmysql.dylib .../brew/lib/libmysql.dylib: Mach-O 64-bit dynamically linked shared library x86_64 I however need i386 library for my project. I tried to give it CFLAGS and LDFLAGS like this: CFLAGS="-arch i386 -arch x86_64" LDFLAGS="-arch i386 -arch x86_64" brew install mysql-connector-c but nothing changes - it still builds x86_64 only binary. Is there any way to make homebrew build either dual arch library or i386 library? I have kernel architecture set to x86_64, if it matters.

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  • Attaching new animations onto skeleton via props, a good idea?

    - by Cardin
    I'm thinking of coding a game with an idea of mine. I've coded 2D games before, but I'm new to 3D programming, so I'd like to ask if this idea of mine is feasible or out of my depth. I'm making a game where there are many different characters for the player to choose from (JRPG style). So to save time, I have an idea of creating many different varied characters using a completely naked body mesh and animation skeleton, standardised across all characters. For example, by placing different hair, boots, armor props on the character mesh, new characters can be formed. Kinda like playing dress-up with a barbie doll. I'm thinking this can be done by having a bone on the prop that I can programmically attach to the main mesh. Also, I plan to have some props add new animations to the base skeleton, so equipping some particular props would give it new attack, damage, idle animations. This is because I can't expect the character to have the same swinging animation if he had a big sword or an axe. I think this might be possible if the prop has its own instance of the animation skeleton with just only the new animations, and parenting the base body mesh to this new skeleton. So all the base body mesh has are just the basic animations, other animations come from the props. My concerns are, 1) the props might not attach to the mesh properly and jitter a lot, 2) since prop and body are animated differently, the props and base mesh will cause visual artefacts, like the naked thighs showing through the pants when the character walks, 3) a custom pipeline have to be developed to export skeletons without mesh, and also to attach the base body mesh to a new skeleton during runtime in the game. So my question: are these features considered 'easy' to code? Or am I trying to do something few have ever succeeded with on their own? It feels like all these can be done given enough time and I know I definitely have to do a bit of bone matrix calculations, but I really don't want to drag out the development timeline unnecessarily from coding mathematically intense things or analyzing how to parse 3D export formats. I'm currently only at the Game Design stage, so if these features aren't a good idea, I can simply change the design of the game. (Unrelated to question) I could always, as last resort, have the characters have predetermined outfit and weapon selections so as to animate everything manually.

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  • Using static in PHP

    - by nischayn22
    I have a few functions in PHP that read data from functions in a class readUsername(int userId){ $reader = getReader(); return $reader->getname(userId); } readUserAddress(){ $reader = getReader(); return $reader->getaddress(userId); } All these make a call to getReader() { require_once("Reader.php"); static $reader = new Reader(); return $reader; } An overview of Reader class Reader{ getname(int id) { //if in-memory cache exists for this id return that //else get from db and cache it } getaddress(int id) { $this->getname(int id); //get address from name here } /*Other stuff*/ } Why is class Reader needed The Reader class does some in-memory caching of user details. So, I need only one object of class Reader and it will cache the user details instead of making multiple db calls. I am using static so that it the object gets created only once. Is this the right approach or should I do something else?

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  • CI tests to enforce specific development rules - good practice?

    - by KeithS
    The following is all purely hypothetical and any particular portion of it may or may not accurately describe real persons or situations, whether living, dead or just pretending. Let's say I'm a senior dev or architect in charge of a dev team working on a project. This project includes a security library for user authentication/authorization of the application under development. The library must be available for developers to edit; however, I wish to "trust but verify" that coders are not doing things that could compromise the security of the finished system, and because this isn't my only responsibility I want it to be done in an automated way. As one example, let's say I have an interface that represents a user which has been authenticated by the system's security library. The interface exposes basic user info and a list of things the user is authorized to do (so that the client app doesn't have to keep asking the server "can I do this?"), all in an immutable fashion of course. There is only one implementation of this interface in production code, and for the purposes of this post we can say that all appropriate measures have been taken to ensure that this implementation can only be used by the one part of our code that needs to be able to create concretions of the interface. The coders have been instructed that this interface and its implementation are sacrosanct and any changes must go through me. However, those are just words; the security library's source is open for editing by necessity. Any of my devs could decide that this secured, private, hash-checked implementation needs to be public so that they could do X, or alternately they could create their own implementation of this public interface in a different library, exposing the hashing algorithm that provides the secure checksum, in order to do Y. I may not be made aware of these changes so that I can beat the developer over the head for it. An attacker could then find these little nuggets in an unobfuscated library of the compiled product, and exploit it to provide fake users and/or falsely-elevated administrative permissions, bypassing the entire security system. This possibility keeps me awake for a couple of nights, and then I create an automated test that reflectively checks the codebase for types deriving from the interface, and fails if it finds any that are not exactly what and where I expect them to be. I compile this test into a project under a separate folder of the VCS that only I have rights to commit to, have CI compile it as an external library of the main project, and set it up to run as part of the CI test suite for user commits. Now, I have an automated test under my complete control that will tell me (and everyone else) if the number of implementations increases without my involvement, or an implementation that I did know about has anything new added or has its modifiers or those of its members changed. I can then investigate further, and regain the opportunity to beat developers over the head as necessary. Is this considered "reasonable" to want to do in situations like this? Am I going to be seen in a negative light for going behind my devs' backs to ensure they aren't doing something they shouldn't?

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  • How to convince management of making our project open source?

    - by MrSoundless
    Xamarin 3 was released last week with a great new addition: Xamarin.Forms . This triggered our attention because we've been using such a system for a couple of years now. We've developed it by ourselves and used it for a bunch of projects. We've been looking for a way to make this project open source but we didn't manage to convince the management. They believe we should not make it open source because we won't win anything with it and all that will happen is that the competition will be able to build apps quicker with our library. We believe open sourcing our library will make the world a better place and that it will make our library much more stable and complete. So my question to all you people out there: How can we convince the management to open source our library?

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  • A Better Way to Plan, Execute and Manage Enterprise Architecture

    - by JuergenKress
    IT Strategies from Oracle is an authorized library of guidelines and reference architectures that will help you better plan, execute, and manage your enterprise architecture and IT initiatives. The IT Strategies from Oracle library offers two types of best practice documents: practitioner guides containing pragmatic advice and approaches, and reference architectures containing the proven technology patterns to jumpstart your initiative. The IT Strategies from Oracle library can help you establish a reliable set of principles and standards to guide your use of Oracle technology. We will expand this library over time across all of Oracle's technologies. Today, you can access: Overview documents providing an introduction to all the resources available in the library and best practices maturity models Oracle Reference Architectures covering the application infrastructure foundation, management and monitoring, security, software engineering, service-oriented integration, service orientation, user interaction, engineered systems, and a master glossary. Enterprise Technology Strategies for Service-Oriented Architecture offering practitioner guides on creating a SOA roadmap, frameworks for governance, determining ROI, identifying services, software engineering, and white papers. Enterprise Technology Strategies for Event-Driven Architecture offering practitioner guides on creating an EDA roadmap and reference architectures on an EDA foundation and EDA infrastructure. Enterprise Technology Strategies for Business Process Management including practitioner guides on creating a BPM roadmap, business process engineering, governance, and reference architectures on a BPM foundation and BPM infrastructure. Enterprise Technology Strategies for Cloud Computing including reference architectures on a Cloud foundation and Cloud infrastructure. Enterprise Technology Strategies for Business Analytics includes a practitioner guide for creating a BA roadmap, and reference architectures for a BA foundation and BA infrastructure. Get the Oracle Enterprise Architecture content here. SOA & BPM Partner Community For regular information on Oracle SOA Suite become a member in the SOA & BPM Partner Community for registration please visit www.oracle.com/goto/emea/soa (OPN account required) If you need support with your account please contact the Oracle Partner Business Center. Blog Twitter LinkedIn Facebook Wiki Mix Forum Technorati Tags: Architecture,SOA Community,Oracle SOA,Oracle BPM,Community,OPN,Jürgen Kress

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  • align to the bottom of the div [closed]

    - by dole
    I need to arange the value and the lorem ipsum text to the bottom of the div as in the following image, but everything I've tryed until now doesn't work. My html looks like this: <div class="product"> <span class="title">Lorem Ipsum</span> <div class="values"> <span class="price">$29,225</span> <span class="description">Lorem ipsum dolor sit amet, consectetur ...</span> </div> </div>

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  • MS TechDays &ndash; My WP7 Talk&rsquo;s Links and Notes

    - by D'Arcy Lussier
    I hope those that attended my Windows Phone 7 talk this morning at Winnipeg TechDays enjoyed it! As promised, below are relevant links and info from my session. Differences Between Silverlight on Windows and Windows Phone http://msdn.microsoft.com/en-us/library/ff426930(VS.96).aspx#Controls Isolated Storage Best Practices for Windows Phone http://msdn.microsoft.com/en-us/library/ff769544(v=VS.92).aspx Class Library Support for Windows Phone http://msdn.microsoft.com/en-us/library/dd470087(v=VS.96).aspx AppHub and Windows Phone 7 Development Tools http://create.msdn.com Windows Phone 7 Application Certification Requirements (PDF Document) http://go.microsoft.com/fwlink/?LinkID=183220 My Blog Post on WP7 and Micro SD Cards – What You Need To Know http://geekswithblogs.net/dlussier/archive/2010/11/10/142667.aspx If there’s anything else from my presentation that you’d like to know, please comment and let me know!

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  • Z-index preventing on hover attribute on another element [migrated]

    - by user18294
    I have two different elements (div class="") within a larger container. Let's call them div class="overlay_container" and div class="title." The div class="overlay_container" has a subclass, .image, which creates an overlay over the entire larger container on hover. The div class="title" has a z-index of 10,000 and lies over .image and therefore over the overlay. Unfortunately, when you hover over "title," the subclass overlay image underneath disappears. I know the problem is obviously that the "title" div is right over the other divs and therefore the on hover will disappear due to the z-index. But how do I fix this? How do I make it so that when you hover over the "title," the .image overlay still appears? If your answer involves jQuery, could you please tell me where to put the script (before the /head tag)? Thanks!

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  • C++ strongly typed typedef

    - by Kian
    I've been trying to think of a way of declaring strongly typed typedefs, to catch a certain class of bugs in the compilation stage. It's often the case that I'll typedef an int into several types of ids, or a vector to position or velocity: typedef int EntityID; typedef int ModelID; typedef Vector3 Position; typedef Vector3 Velocity; This can make the intent of code more clear, but after a long night of coding one might make silly mistakes like comparing different kinds of ids, or adding a position to a velocity perhaps. EntityID eID; ModelID mID; if ( eID == mID ) // <- Compiler sees nothing wrong { /*bug*/ } Position p; Velocity v; Position newP = p + v; // bug, meant p + v*s but compiler sees nothing wrong Unfortunately, suggestions I've found for strongly typed typedefs include using boost, which at least for me isn't a possibility (I do have c++11 at least). So after a bit of thinking, I came upon this idea, and wanted to run it by someone. First, you declare the base type as a template. The template parameter isn't used for anything in the definition, however: template < typename T > class IDType { unsigned int m_id; public: IDType( unsigned int const& i_id ): m_id {i_id} {}; friend bool operator==<T>( IDType<T> const& i_lhs, IDType<T> const& i_rhs ); }; Friend functions actually need to be forward declared before the class definition, which requires a forward declaration of the template class. We then define all the members for the base type, just remembering that it's a template class. Finally, when we want to use it, we typedef it as: class EntityT; typedef IDType<EntityT> EntityID; class ModelT; typedef IDType<ModelT> ModelID; The types are now entirely separate. Functions that take an EntityID will throw a compiler error if you try to feed them a ModelID instead, for example. Aside from having to declare the base types as templates, with the issues that entails, it's also fairly compact. I was hoping anyone had comments or critiques about this idea? One issue that came to mind while writing this, in the case of positions and velocities for example, would be that I can't convert between types as freely as before. Where before multiplying a vector by a scalar would give another vector, so I could do: typedef float Time; typedef Vector3 Position; typedef Vector3 Velocity; Time t = 1.0f; Position p = { 0.0f }; Velocity v = { 1.0f, 0.0f, 0.0f }; Position newP = p + v*t; With my strongly typed typedef I'd have to tell the compiler that multypling a Velocity by a Time results in a Position. class TimeT; typedef Float<TimeT> Time; class PositionT; typedef Vector3<PositionT> Position; class VelocityT; typedef Vector3<VelocityT> Velocity; Time t = 1.0f; Position p = { 0.0f }; Velocity v = { 1.0f, 0.0f, 0.0f }; Position newP = p + v*t; // Compiler error To solve this, I think I'd have to specialize every conversion explicitly, which can be kind of a bother. On the other hand, this limitation can help prevent other kinds of errors (say, multiplying a Velocity by a Distance, perhaps, which wouldn't make sense in this domain). So I'm torn, and wondering if people have any opinions on my original issue, or my approach to solving it.

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