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  • Cocos2d Box2d how to shoot an object inside the screen

    - by Ahoura Ghotbi
    I have the code below : - (id) initWithGame:(mainGame*)game { if ((self = [super init])) { isTouchEnabled_ = YES; self.game = game; CGSize size = [[CCDirector sharedDirector] winSize]; screenH = size.height; screenW = size.width; character = [CCSprite spriteWithFile:@"o.png"]; character.position = ccp( size.width /2 , size.height/2 ); character.contentSize = CGSizeMake(72, 79); [self addChild:character z:10 tag:1]; _body = NULL; _radius = 14.0f; // Create ball body and shape b2BodyDef ballBodyDef; ballBodyDef.type = b2_dynamicBody; ballBodyDef.position.Set(100/PTM_RATIO, 100/PTM_RATIO); ballBodyDef.userData = character; _body = _game.world->CreateBody(&ballBodyDef); b2CircleShape circle; circle.m_radius = 26.0/PTM_RATIO; b2FixtureDef ballShapeDef; ballShapeDef.shape = &circle; ballShapeDef.density = 1.0f; ballShapeDef.friction = 0.2f; ballShapeDef.restitution = 0.8f; _body->CreateFixture(&ballShapeDef); [self schedule:@selector(gameChecker:)]; [self schedule:@selector(tick:)]; } return self; } - (void)gameChecker:(ccTime) dt{ if(character.position.y > 200){ [self unschedule:@selector(tick:)]; [self schedule:@selector(dropObject:)]; } } - (void)tick:(ccTime) dt { b2Vec2 force; force.Set(_body->GetLinearVelocity().x, _body->GetLinearVelocity().y+1.0f); for (b2Body* b = _game.world->GetBodyList(); b; b = b->GetNext()) { if (b->GetUserData() == character) { b->SetLinearVelocity(force); } } _game.world->Step(dt, 10, 10); for(b2Body *b = _game.world->GetBodyList(); b; b=b->GetNext()) { if (b->GetUserData() != NULL) { CCSprite *ballData = (CCSprite *)b->GetUserData(); ballData.position = ccp(b->GetPosition().x * PTM_RATIO, b->GetPosition().y * PTM_RATIO); ballData.rotation = -1 * CC_RADIANS_TO_DEGREES(b->GetAngle()); } } } -(void)dropObject:(ccTime) dt{ b2Vec2 force; force.Set(_body->GetLinearVelocity().x, _body->GetLinearVelocity().y-1.0f); for (b2Body* b = _game.world->GetBodyList(); b; b = b->GetNext()) { if (b->GetUserData() == character) { b->SetLinearVelocity(force); } } _game.world->Step(dt, 10, 10); for(b2Body *b = _game.world->GetBodyList(); b; b=b->GetNext()) { if (b->GetUserData() != NULL) { CCSprite *ballData = (CCSprite *)b->GetUserData(); ballData.position = ccp(b->GetPosition().x * PTM_RATIO, b->GetPosition().y * PTM_RATIO); ballData.rotation = -1 * CC_RADIANS_TO_DEGREES(b->GetAngle()); } } } I have been trying to get the effect that fruit ninja has when shooting the fruits. but it seems like its hard to get such animation so I was wondering if anyone can point me to the right direction and/or give me a sample code for a single object that gets thrown into the screen with a direction.

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  • Indexing data from multiple tables with Oracle Text

    - by Roger Ford
    It's well known that Oracle Text indexes perform best when all the data to be indexed is combined into a single index. The query select * from mytable where contains (title, 'dog') 0 or contains (body, 'cat') 0 will tend to perform much worse than select * from mytable where contains (text, 'dog WITHIN title OR cat WITHIN body') 0 For this reason, Oracle Text provides the MULTI_COLUMN_DATASTORE which will combine data from multiple columns into a single index. Effectively, it constructs a "virtual document" at indexing time, which might look something like: <title>the big dog</title> <body>the ginger cat smiles</body> This virtual document can be indexed using either AUTO_SECTION_GROUP, or by explicitly defining sections for title and body, allowing the query as expressed above. Note that we've used a column called "text" - this might have been a dummy column added to the table simply to allow us to create an index on it - or we could created the index on either of the "real" columns - title or body. It should be noted that MULTI_COLUMN_DATASTORE doesn't automatically handle updates to columns used by it - if you create the index on the column text, but specify that columns title and body are to be indexed, you will need to arrange triggers such that the text column is updated whenever title or body are altered. That works fine for single tables. But what if we actually want to combine data from multiple tables? In that case there are two approaches which work well: Create a real table which contains a summary of the information, and create the index on that using the MULTI_COLUMN_DATASTORE. This is simple, and effective, but it does use a lot of disk space as the information to be indexed has to be duplicated. Create our own "virtual" documents using the USER_DATASTORE. The user datastore allows us to specify a PL/SQL procedure which will be used to fetch the data to be indexed, returned in a CLOB, or occasionally in a BLOB or VARCHAR2. This PL/SQL procedure is called once for each row in the table to be indexed, and is passed the ROWID value of the current row being indexed. The actual contents of the procedure is entirely up to the owner, but it is normal to fetch data from one or more columns from database tables. In both cases, we still need to take care of updates - making sure that we have all the triggers necessary to update the indexed column (and, in case 1, the summary table) whenever any of the data to be indexed gets changed. I've written full examples of both these techniques, as SQL scripts to be run in the SQL*Plus tool. You will need to run them as a user who has CTXAPP role and CREATE DIRECTORY privilege. Part of the data to be indexed is a Microsoft Word file called "1.doc". You should create this file in Word, preferably containing the single line of text: "test document". This file can be saved anywhere, but the SQL scripts need to be changed so that the "create or replace directory" command refers to the right location. In the example, I've used C:\doc. multi_table_indexing_1.sql : creates a summary table containing all the data, and uses multi_column_datastore Download link / View in browser multi_table_indexing_2.sql : creates "virtual" documents using a procedure as a user_datastore Download link / View in browser

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  • Be the surgeon

    - by Rob Farley
    It’s a phrase I use often, especially when teaching, and I wish I had realised the concept years earlier. (And of course, fits with this month’s T-SQL Tuesday topic, hosted by Argenis Fernandez) When I’m sick enough to go to the doctor, I see a GP. I used to typically see the same guy, but he’s moved on now. However, when he has been able to roughly identify the area of the problem, I get referred to a specialist, sometimes a surgeon. Being a surgeon requires a refined set of skills. It’s why they often don’t like to be called “Doctor”, and prefer the traditional “Mister” (the history is that the doctor used to make the diagnosis, and then hand the patient over to the person who didn’t have a doctorate, but rather was an expert cutter, typically from a background in butchering). But if you ask the surgeon about the pain you have in your leg sometimes, you’ll get told to ask your GP. It’s not that your surgeon isn’t interested – they just don’t know the answer. IT is the same now. That wasn’t something that I really understood when I got out of university. I knew there was a lot to know about IT – I’d just done an honours degree in it. But I also knew that I’d done well in just about all my subjects, and felt like I had a handle on everything. I got into developing, and still felt that having a good level of understanding about every aspect of IT was a good thing. This got me through for the first six or seven years of my career. But then I started to realise that I couldn’t compete. I’d moved into management, and was spending my days running projects, rather than writing code. The kids were getting older. I’d had a bad back injury (ask anyone with chronic pain how it affects  your ability to concentrate, retain information, etc). But most of all, IT was getting larger. I knew kids without lives who knew more than I did. And I felt like I could easily identify people who were better than me in whatever area I could think of. Except writing queries (this was before I discovered technical communities, and people like Paul White and Dave Ballantyne). And so I figured I’d specialise. I wish I’d done it years earlier. Now, I can tell you plenty of people who are better than me at any area you can pick. But there are also more people who might consider listing me in some of their lists too. If I’d stayed the GP, I’d be stuck in management, and finding that there were better managers than me too. If you’re reading this, SQL could well be your thing. But it might not be either. Your thing might not even be in IT. Find out, and then see if you can be a world-beater at it. But it gets even better, because you can find other people to complement the things that you’re not so good at. My company, LobsterPot Solutions, has six people in it at the moment. I’ve hand-picked those six people, along with the one who quit. The great thing about it is that I’ve been able to pick people who don’t necessarily specialise in the same way as me. I don’t write their T-SQL for them – generally they’re good enough at that themselves. But I’m on-hand if needed. Consider Roger Noble, for example. He’s doing stuff in HTML5 and jQuery that I could never dream of doing to create an amazing HTML5 version of PivotViewer. Or Ashley Sewell, a guy who does project management far better than I do. I could go on. My team is brilliant, and I love them to bits. We’re all surgeons, and when we work together, I like to think we’re pretty good! @rob_farley

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  • WebLogic Server–Use the Execution Context ID in Applications–Lessons From Hansel and Gretel

    - by james.bayer
    I learned a neat trick this week.  Don’t let your breadcrumbs go to waste like Hansel and Gretel did!  Keep track of the code path, logs and errors for each request as they flow through the system.  Earlier this week an OTN forum post in the WLS – General category by Oracle Ace John Stegeman asked a question how to retrieve the Execution Context ID so that it could be used on an error page that a user could provide to a help desk or use to check with application administrators so they could look up what went wrong.  What is the Execution Context ID (ECID)?  Fusion Middleware injects an ECID as a request enters the system and it says with the request as it flows from Oracle HTTP Server to Oracle Web Cache to multiple WebLogic Servers to the Oracle Database. It’s a way to uniquely identify a request across tiers.  According to the documentation it’s: The value of the ECID is a unique identifier that can be used to correlate individual events as being part of the same request execution flow. For example, events that are identified as being related to a particular request typically have the same ECID value.  The format of the ECID string itself is determined by an internal mechanism that is subject to change; therefore, you should not have or place any dependencies on that format. The novel idea that I see John had was to extend this concept beyond the diagnostic information that is captured by Fusion Middleware.  Why not also use this identifier in your logs and errors so you can correlate even more information together!  Your logging might already identify the user, so why not identify the request so you filter down even more.  All you need to do inside of WebLogic Server to get ahold of this information is invoke DiagnosticConextHelper: weblogic.diagnostics.context.DiagnosticContextHelper.getContextId() This class has other helpful methods to see other values tracked by the diagnostics framework too.  This way I can see even more detail and get information across tiers. In performance profiling, this can be very handy to track down where time is being spent in code.  I’ve blogged and made videos about this before.  JRockit Flight Recorder can use the WLDF Diagnostic Volume in WLS 10.3.3+ to automatically capture and correlate lots of helpful information for each request without installing any special agents and with the out-of-the-box JRockit and WLS settings!  You can see here how information is displayed in JRockit Flight Recorder about a single request as it calls a Servlet, which calls an EJB, which gets a DB connection, which starts a transaction, etc.  You can get timings around everything and even see the SQL that is used. http://download.oracle.com/docs/cd/E21764_01/web.1111/e13714/using_flightrecorder.htm#WLDFC480 Recent versions of the WLS console also are able to visualize this data too, so it works with other JVMs besides JRockit when you turn on WLDF instrumentation. I wrote a little sample application that verified to myself that the ECID did actually cross JVM boundaries.  I invoked a Servlet in one JVM, which acted as an EJB client to Stateless Session Bean running in another JVM.  Each call returned the same ECID.  You need to turn on WLDF Instrumentation for this to work otherwise the framework returns null.  I’m glad John put me on to this API as I have some interesting ideas on how to correlate some information together.

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  • Subterranean IL: Compiling C# exception handlers

    - by Simon Cooper
    An exception handler in C# combines the IL catch and finally exception handling clauses into a single try statement: try { Console.WriteLine("Try block") // ... } catch (IOException) { Console.WriteLine("IOException catch") // ... } catch (Exception e) { Console.WriteLine("Exception catch") // ... } finally { Console.WriteLine("Finally block") // ... } How does this get compiled into IL? Initial implementation If you remember from my earlier post, finally clauses must be specified with their own .try clause. So, for the initial implementation, we take the try/catch/finally, and simply split it up into two .try clauses (I have to use label syntax for this): StartTry: ldstr "Try block" call void [mscorlib]System.Console::WriteLine(string) // ... leave.s End EndTry: StartIOECatch: ldstr "IOException catch" call void [mscorlib]System.Console::WriteLine(string) // ... leave.s End EndIOECatch: StartECatch: ldstr "Exception catch" call void [mscorlib]System.Console::WriteLine(string) // ... leave.s End EndECatch: StartFinally: ldstr "Finally block" call void [mscorlib]System.Console::WriteLine(string) // ... endfinally EndFinally: End: // ... .try StartTry to EndTry catch [mscorlib]System.IO.IOException handler StartIOECatch to EndIOECatch catch [mscorlib]System.Exception handler StartECatch to EndECatch .try StartTry to EndTry finally handler StartFinally to EndFinally However, the resulting program isn't verifiable, and doesn't run: [IL]: Error: Shared try has finally or fault handler. Nested try blocks What's with the verification error? Well, it's a condition of IL verification that all exception handling regions (try, catch, filter, finally, fault) of a single .try clause have to be completely contained within any outer exception region, and they can't overlap with any other exception handling clause. In other words, IL exception handling clauses must to be representable in the scoped syntax, and in this example, we're overlapping catch and finally clauses. Not only is this example not verifiable, it isn't semantically correct. The finally handler is specified round the .try. What happens if you were able to run this code, and an exception was thrown? Program execution enters top of try block, and exception is thrown within it CLR searches for an exception handler, finds catch Because control flow is leaving .try, finally block is run The catch block is run leave.s End inside the catch handler branches to End label. We're actually running the finally before the catch! What we do about it What we actually need to do is put the catch clauses inside the finally clause, as this will ensure the finally gets executed at the correct time (this time using scoped syntax): .try { .try { ldstr "Try block" call void [mscorlib]System.Console::WriteLine(string) // ... leave.s End } catch [mscorlib]System.IO.IOException { ldstr "IOException catch" call void [mscorlib]System.Console::WriteLine(string) // ... leave.s End } catch [mscorlib]System.Exception { ldstr "Exception catch" call void [mscorlib]System.Console::WriteLine(string) // ... leave.s End } } finally { ldstr "Finally block" call void [mscorlib]System.Console::WriteLine(string) // ... endfinally } End: ret Returning from methods There is a further semantic mismatch that the C# compiler has to deal with; in C#, you are allowed to return from within an exception handling block: public int HandleMethod() { try { // ... return 0; } catch (Exception) { // ... return -1; } } However, you can't ret inside an exception handling block in IL. So the C# compiler does a leave.s to a ret outside the exception handling area, loading/storing any return value to a local variable along the way (as leave.s clears the stack): .method public instance int32 HandleMethod() { .locals init ( int32 retVal ) .try { // ... ldc.i4.0 stloc.0 leave.s End } catch [mscorlib]System.Exception { // ... ldc.i4.m1 stloc.0 leave.s End } End: ldloc.0 ret } Conclusion As you can see, the C# compiler has quite a few hoops to jump through to translate C# code into semantically-correct IL, and hides the numerous conditions on IL exception handling blocks from the C# programmer. Next up: catch-all blocks, and how the runtime deals with non-Exception exceptions.

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  • Unity GUI not in build, but works fine in editor

    - by Darren
    I have: GUITexture attached to an object A script that has GUIStyles created for the Textfield and Buttons that are created in OnGUI(). This script is attached to the same object in number 1 3 GUIText objects each separate from the above. A script that enables the GUITexture and the script in number 1 and 2 respectively This is how it is supposed to work: When I cross the finish line, number 4 script enables number 1 GUITexture component and number 2 script component. The script component uses one of number 3's GUIText objects to show you your best lap time, and also makes a GUI.Textfield for name entry and 2 GUI.Buttons for "Submit" and "Skip". If you hit "Submit" the script will submit the time. No matter which button you press, The remaining 2 GUIText objects from number 3 will show you the top 10 best times. For some reason, when I run it in editor, everything works 100%, but when I'm in different kinds of builds, the results vary. When I am in a webplayer, The GUITexture and the textfield and buttons appear, but the textfield and buttons are plain and have no evidence of GUIStyles. When I click one of the buttons, the score gets submitted but I do not get the fastest times showing. When I am in a standalone build, the GUITexture shows up, but nothing else does. If I remove the GUIStyle parameter of the GUI.Textfield and GUI.Button, they show up. Why am I getting these variations and how can I fix it? Code below: void Start () { Names.text = ""; Times.text = ""; YourBestTime.text = "Your Best Lap: " + bestTime + "\nEnter your name:"; //StartCoroutine(GetTimes("Test")); } void Update() { if (!ShowButtons && !GettingTimes) { StartCoroutine(GetTimes()); GettingTimes = true; } } IEnumerator GetTimes () { Debug.Log("Getting times"); YourBestTime.text = "Loading Best Lap Times"; WWW times_get = new WWW(GetTimesUrl); yield return times_get; WWW names_get = new WWW(GetNamesUrl); yield return names_get; if(times_get.error != null || names_get.error != null) { print("There was an error retrieiving the data: " + names_get.error + times_get.error); } else { Times.text = times_get.text; Names.text = names_get.text; YourBestTime.text = "Your Best Lap: " + bestTime; } } IEnumerator PostLapTime (string Name, string LapTime) { string hash= MD5.Md5Sum(Name + LapTime + secretKey); string bestTime_url = SubmitTimeUrl + "&Name=" + WWW.EscapeURL(Name) + "&LapTime=" + LapTime + "&hash=" + hash; Debug.Log (bestTime_url); // Post the URL to the site and create a download object to get the result. WWW hs_post = new WWW(bestTime_url); //label = "Submitting..."; yield return hs_post; // Wait until the download is done if (hs_post.error != null) { print("There was an error posting the lap time: " + hs_post.error); //label = "Error: " + hs_post.error; //show = false; } else { Debug.Log("Posted: " + hs_post.text); ShowButtons = false; PostingTime = false; } } void OnGUI() { if (ShowButtons) { //makes text box nameString = GUI.TextField( new Rect((Screen.width/2)-111, (Screen.height/2)-130, 222, 25), nameString, 20, TextboxStyle); if (GUI.Button( new Rect( (Screen.width/2-74.0f), (Screen.height/2)- 90, 64, 32), "Submit", ButtonStyle)) { //SUBMIT TIME if (nameString == "") { nameString = "Player"; } if (!PostingTime) { StartCoroutine(PostLapTime(nameString, bestTime)); PostingTime = true; } } else if (GUI.Button( new Rect( (Screen.width/2+10.0f), (Screen.height/2)- 90, 64, 32), "Skip", ButtonStyle)) { ShowButtons = false; } } } }

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  • Review&ndash;Build Android and iOS apps in Visual Studio with Nomad

    - by Bill Osuch
    Nomad is a Visual Studio extension that allows you build apps for both Android and iOS platforms in Visual Studio using HTML5. There is no need to switch between .Net, Java and Objective-C to target different platforms - write your code once in HTML5 and build for all common mobile platforms and tablets. You have access to the native hardware functions (such as camera and GPS) through the PhoneGap library, UI libraries such as jQuery mobile allow you to create an impressive UI with minimal work. Nomad is still in an early access beta stage, so the documentation is a bit sparse. In fact, the only documentation is a simple series of steps on how to install the plug-in, set up a project, build and deploy it. You're going to want to be a least a little familiar with the PhoneGap library and jQuery mobile to really tap into the power of this. The sample project included with the download shows you just how simple it is to create projects in Visual Studio. The sample solution comes with an index.html file containing the HTML5 code, the Cordova (PhoneGap) library, jQuery libraries, and a JQuery style sheet: The html file is pretty straightforward. If you haven't experimented with JQuery mobile before, some of the attributes (such as data-role) might be new to you, but some quick Googling will fill in everything you need to know. The first part of the file builds a simple (but attractive) list with some links in it: The second part of the file is where things get interesting and it taps into the PhoneGap library. For instance, it gets the geolocation position by calling position.coords.latitude and position.coords.longitude: ...and then displays it in a simple span: Building is pretty simple, at least for Android (I'm not an iOS developer so I didn't look at that feature) - just configure the display name, version number, and package ID. There's no need to specify Android version; Nomad supports 2.2 and later. Enter these bits of information, click the new "Build for Android" button (not the regular Visual Studio Build link...) and you get a dialog box saying that your code is being built by their cloud build service (so no building while away from a WiFi signal apparently). After a couple minutes you wind up with a .apk file that can be copied over to your device. Applications built with Nomad for Android currently use a temporary certificate, so you can test the app on your devices but you cannot publish them in the Google Play Store (yet). And I love the "success" dialog box: Since Nomad is still in Beta, no pricing plans have been announced yet, so I'll be curious to see if this becomes a cost-effective solution to mobile app development. If it is, I may even be tempted to spring for the $99 iOS membership fee! In the meantime, I plan to work on porting some of my apps over to it and seeing how they work. My only quibble at this time is the lack of a centralized documentation location - I'd like to at least see which (if any) features of JQuery and PhoneGap are limited or not supported. Also, some notes on targeting different Android screen sizes would be nice, but it's relatively easy to find jQuery examples out on the InterWebs. Oh well, trial and error! You can download the Nomad extension for Visual Studio by going to their web site: www.vsnomad.com. Technorati Tags: Android, Nomad

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  • Oracle MDM Maturity Model

    - by David Butler
    A few weeks ago, I discussed the results of a survey conducted by Oracle’s Insight team. The survey was based on the data management maturity model that the Oracle Insight team has developed over the years as they analyzed customer IT organizations to help them get more out of everything they already have. I thought you might like to learn more about the maturity model itself. It can help you figure out where you stand when it comes to getting your organizations data management act together. The model covers maturity levels around five key areas: Profiling data sources; Defining a data strategy; Defining a data consolidation plan; Data maintenance; and Data utilization. Profile data sources: Profiling data sources involves taking an inventory of all data sources from across your IT landscape. Then evaluate the quality of the data in each source system. This enables the scoping of what data to collect into an MDM hub and what rules are needed to insure data harmonization across systems. Define data strategy: A data strategy requires an understanding of the data usage. Given data usage, various data governance requirements need to be developed. This includes data controls and security rules as well as data structure and usage policies. Define data consolidation strategy: Consolidation requires defining your operational data model. How integration is to be accomplished. Cross referencing common data attributes from multiple systems is needed. Synchronization policies also need to be developed. Data maintenance: The desired standardization needs to be defined, including what constitutes a ‘match’ once the data has been standardized. Cleansing rules are a part of this methodology. Data quality monitoring requirements also need to be defined. Utilize the data: What data gets published, and who consumes the data must be determined. How to get the right data to the right place in the right format given its intended use must be understood. Validating the data and insuring security rules are in place and enforced are crucial aspects for full no-risk data utilization. For each of the above data management areas, a maturity level needs to be assessed. Where your organization wants to be should also be identified using the same maturity levels. This results in a sound gap analysis your organization can use to create action plans to achieve the ultimate goals. Marginal is the lowest level. It is characterized by manually maintaining trusted sources; lacking or inconsistent, silo’d structures with limited integration, and gaps in automation. Stable is the next leg up the MDM maturity staircase. It is characterized by tactical MDM implementations that are limited in scope and target a specific division.  It includes limited data stewardship capabilities as well. Best Practice is a serious MDM maturity level characterized by process automation improvements. The scope is enterprise wide. It is a business solution that provides a single version of the truth, with closed-loop data quality capabilities. It is typically driven by an enterprise architecture group with both business and IT representation.   Transformational is the highest MDM maturity level. At this level, MDM is quantitatively managed. It is integrated with Business Intelligence, SOA, and BPM. MDM is leveraged in business process orchestration. Take an inventory using this MDM Maturity Model and see where you are in your journey to full MDM maturity with all the business benefits that accrue to organizations who have mastered their data for the benefit of all operational applications, business processes, and analytical systems. To learn more, Trevor Naidoo and I have written the Oracle MDM Maturity Model whitepaper. It’s free, so go ahead and download it and use it as you see fit.

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  • Educational, well-written FOSS projects to read, study or discuss

    - by Godot
    Before you say it: yes, this "question" has been asked other times. However, I could not fine many of such questions and not that easily, and those I found had similar results. What I'm trying to say that there are no comprehensive lists of well written Open Source projects, so I decided to set some requirements for the entries (one or possibly more): Idiomatic use of the language in which they are written The project should be lightweight. Not as in "a few kbs", as in "clean" and possibly following the UNIX philosophy, making an efficient use of resources and performing its duty and nothing more. No code bloat, most importantly. Projects like Firefox and GNOME wouldn't qualify, for example. Minimal reliance on external, non-standard libraries, with exceptions for some common FOSS libraries (curses, Xlib, OpenGL and possibly "usual suspects" like gtk+, webkit and Boost). Reliance on well-written libraries is welcome. No reliance on proprietary software - for obvious reasons (programs that rely on XNA, DirectX, Cocoa and similar, for example). Well-documented code is welcome. Include link to web interfaces to their repositories if possible. Here are some sample projects that often pop up in these threads: Operating Systems Plan 9 from Bell Labs: More or less, the official "sequel" to UNIX. Written in C by the same people who invented C! NetBSD: The most portable BSD implementation, written in C and also a good example of portable and organized code. Network and Databases Sqlite: Extremely lightweight and extremely efficient, one of the best pieces of C software I've seen. Count the lines yourself! Lighttpd: A small but pretty reliable web server written in C. Programming languages and VMs Lua: extremely lightweight multi-paradigm programming language. Written in C. Tiny C Compiler: Really tiny C compiler. Not really comparable to GCC or Clang but does its job. PyPy: A Python implementation written in Python. Pharo: OK, I admit it, I'm not really a Smalltalk expert but Pharo is a fork of Squeak and looked rather interesting. Stackless Python - An implementation of Python that doesn't rely on the C call stack - written in C (with some parts in Python) Games and 3D: Angband: One of the most accessible roguelike codebases around here, written in C. Ogre3D: Cross-platform 3D engine. Gets bloated if you don't skip the platform-specific implementation code, otherwise is a pretty solid example of good C++ OO. Simon Tatham's Portable Puzzle Collection: Title says it all. Other - dwm: Lightweight window manager. Written in C. Emulation and Reverse Engineering - Bochs: x86 emulator, written in C++ and tiny enough. - MAME: If you want to see C at one of its lowest levels, MAME is for you. May not be as clean as the other projects but it can teach you A LOT. Before you ask: I didn't mention Linux because it has become quite bloated in the last few years, Linus has also confirmed it. Nonetheless, it'd be a great educational read the same, even if for other reasons. Same for GCC. Feel free to edit or wikify my post. I hope you won't lock my question, I'm only trying to organize a little community effort for the good of all those people who want to enhance their coding skills.

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  • Node.js Lockstep Multiplayer Architecture

    - by Wakaka
    Background I'm using the lockstep model for a multiplayer Node.js/Socket.IO game in a client-server architecture. User input (mouse or keypress) is parsed into commands like 'attack' and 'move' on the client, which are sent to the server and scheduled to be executed on a certain tick. This is in contrast to sending state data to clients, which I don't wish to use due to bandwidth issues. Each tick, the server will send the list of commands on that tick (possibly empty) to each client. The server and all clients will then process the commands and simulate that tick in exactly the same way. With Node.js this is actually quite simple due to possibility of code sharing between server and client. I'll just put the deterministic simulator in the /shared folder which can be run by both server and client. The server simulation is required so that there is an authoritative version of the simulation which clients cannot alter. Problem Now, the game has many entity classes, like Unit, Item, Tree etc. Entities are created in the simulator. However, for each class, it has some methods that are shared and some that are client-specific. For instance, the Unit class has addHp method which is shared. It also has methods like getSprite (gets the image of the entity), isVisible (checks if unit can be seen by the client), onDeathInClient (does a bunch of stuff when it dies only on the client like adding announcements) and isMyUnit (quick function to check if the client owns the unit). Up till now, I have been piling all the client functions into the shared Unit class, and adding a this.game.isServer() check when necessary. For instance, when the unit dies, it will call if (!this.game.isServer()) { this.onDeathInClient(); }. This approach has worked pretty fine so far, in terms of functionality. But as the codebase grew bigger, this style of coding seems a little strange. Firstly, the client code is clearly not shared, and yet is placed under the /shared folder. Secondly, client-specific variables for each entity are also instantiated on the server entity (like unit.sprite) and can run into problems when the server cannot instantiate the variable (it doesn't have Image class like on browsers). So my question is, is there a better way to organize the client code, or is this a common way of doing things for lockstep multiplayer games? I can think of a possible workaround, but it does have its own problems. Possible workaround (with problems) I could use Javascript mixins that are only added when in a browser. Thus, in the /shared/unit.js file in the /shared folder, I would have this code at the end: if (typeof exports !== 'undefined') module.exports = Unit; else mixin(Unit, LocalUnit); Then I would have /client/localunit.js store an object LocalUnit of client-side methods for Unit. Now, I already have a publish-subscribe system in place for events in the simulator. To remove the this.game.isServer() checks, I could publish entity-specific events whenever I want the client to do something. For instance, I would do this.publish('Death') in /shared/unit.js and do this.subscribe('Death', this.onDeathInClient) in /client/localunit.js. But this would make the simulator's event listeners list on the server and the client different. Now if I want to clear all subscribed events only from the shared simulator, I can't. Of course, it is possible to create two event subscription systems - one client-specific and one shared - but now the publish() method would have to do if (!this.game.isServer()) { this.publishOnClient(event); }. All in all, the workaround off the top of my head seems pretty complicated for something as simple as separating the client and shared code. Thus, I wonder if there is an established and simpler method for better code organization, hopefully specific to Node.js games.

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  • How to write simple code using TDD [migrated]

    - by adeel41
    Me and my colleagues do a small TDD-Kata practice everyday for 30 minutes. For reference this is the link for the excercise http://osherove.com/tdd-kata-1/ The objective is to write better code using TDD. This is my code which I've written public class Calculator { public int Add( string numbers ) { const string commaSeparator = ","; int result = 0; if ( !String.IsNullOrEmpty( numbers ) ) result = numbers.Contains( commaSeparator ) ? AddMultipleNumbers( GetNumbers( commaSeparator, numbers ) ) : ConvertToNumber( numbers ); return result; } private int AddMultipleNumbers( IEnumerable getNumbers ) { return getNumbers.Sum(); } private IEnumerable GetNumbers( string separator, string numbers ) { var allNumbers = numbers .Replace( "\n", separator ) .Split( new string[] { separator }, StringSplitOptions.RemoveEmptyEntries ); return allNumbers.Select( ConvertToNumber ); } private int ConvertToNumber( string number ) { return Convert.ToInt32( number ); } } and the tests for this class are [TestFixture] public class CalculatorTests { private int ArrangeAct( string numbers ) { var calculator = new Calculator(); return calculator.Add( numbers ); } [Test] public void Add_WhenEmptyString_Returns0() { Assert.AreEqual( 0, ArrangeAct( String.Empty ) ); } [Test] [Sequential] public void Add_When1Number_ReturnNumber( [Values( "1", "56" )] string number, [Values( 1, 56 )] int expected ) { Assert.AreEqual( expected, ArrangeAct( number ) ); } [Test] public void Add_When2Numbers_AddThem() { Assert.AreEqual( 3, ArrangeAct( "1,2" ) ); } [Test] public void Add_WhenMoreThan2Numbers_AddThemAll() { Assert.AreEqual( 6, ArrangeAct( "1,2,3" ) ); } [Test] public void Add_SeparatorIsNewLine_AddThem() { Assert.AreEqual( 6, ArrangeAct( @"1 2,3" ) ); } } Now I'll paste code which they have written public class StringCalculator { private const char Separator = ','; public int Add( string numbers ) { const int defaultValue = 0; if ( ShouldReturnDefaultValue( numbers ) ) return defaultValue; return ConvertNumbers( numbers ); } private int ConvertNumbers( string numbers ) { var numberParts = GetNumberParts( numbers ); return numberParts.Select( ConvertSingleNumber ).Sum(); } private string[] GetNumberParts( string numbers ) { return numbers.Split( Separator ); } private int ConvertSingleNumber( string numbers ) { return Convert.ToInt32( numbers ); } private bool ShouldReturnDefaultValue( string numbers ) { return String.IsNullOrEmpty( numbers ); } } and the tests [TestFixture] public class StringCalculatorTests { [Test] public void Add_EmptyString_Returns0() { ArrangeActAndAssert( String.Empty, 0 ); } [Test] [TestCase( "1", 1 )] [TestCase( "2", 2 )] public void Add_WithOneNumber_ReturnsThatNumber( string numberText, int expected ) { ArrangeActAndAssert( numberText, expected ); } [Test] [TestCase( "1,2", 3 )] [TestCase( "3,4", 7 )] public void Add_WithTwoNumbers_ReturnsSum( string numbers, int expected ) { ArrangeActAndAssert( numbers, expected ); } [Test] public void Add_WithThreeNumbers_ReturnsSum() { ArrangeActAndAssert( "1,2,3", 6 ); } private void ArrangeActAndAssert( string numbers, int expected ) { var calculator = new StringCalculator(); var result = calculator.Add( numbers ); Assert.AreEqual( expected, result ); } } Now the question is which one is better? My point here is that we do not need so many small methods initially because StringCalculator has no sub classes and secondly the code itself is so simple that we don't need to break it up too much that it gets confusing after having so many small methods. Their point is that code should read like english and also its better if they can break it up earlier than doing refactoring later and third when they will do refactoring it would be much easier to move these methods quite easily into separate classes. My point of view against is that we never made a decision that code is difficult to understand so why we are breaking it up so early. So I need a third person's opinion to understand which option is much better.

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  • Sprinkle Some Magik on that Java Virtual Machine

    - by Jim Connors
    GE Energy, through its Smallworld subsidiary, has been providing geospatial software solutions to the utility and telco markets for over 20 years.  One of the fundamental building blocks of their technology is a dynamically-typed object oriented programming language called Magik.  Like Java, Magik source code is compiled down to bytecodes that run on a virtual machine -- in this case the Magik Virtual Machine. Throughout the years, GE has invested considerable engineering talent in the support and maintenance of this virtual machine.  At the same time vast energy and resources have been invested in the Java Virtual Machine. The question for GE has been whether to continue to make that investment on its own or to leverage massive effort provided by the Java community? Utilizing the Java Virtual Machine instead of maintaining its own virtual machine would give GE more opportunity to focus on application solutions.   At last count, there are dozens, perhaps hundreds of examples of programming languages that have been hosted atop the Java Virtual Machine.  Prior to the release of Java 7, that effort, although certainly possible, was generally less than optimal for languages like Magik because of its dynamic nature.  Java, as a statically typed language had little use for this capability.  In the quest to be a more universal virtual machine, Java 7, via JSR-292, introduced a new bytecode called invokedynamic.  In short, invokedynamic affords a more flexible method call mechanism needed by dynamic languages like Magik. With this new capability GE Energy has succeeded in hosting their Magik environment on top of the Java Virtual Machine.  So you may ask, why would GE wish to do such a thing?  The benefits are many: Competitors to GE Energy claimed that the Magik environment was proprietary.  By utilizing the Java Virtual Machine, that argument gets put to bed.  JVM development is done in open source, where contributions are made world-wide by all types of organizations and individuals. The unprecedented wealth of class libraries and applications written for the Java platform are now opened up to Magik/JVM platform as first class citizens. In addition, the Magik/JVM solution vastly increases the developer pool to include the 9 million Java developers -- the largest developer community on the planet. Applications running on the JVM showed substantial performance gains, in some cases as much as a 5x speed up over the original Magik platform. Legacy Magik applications can still run on the original platform.  They can be seamlessly migrated to run on the JVM by simply recompiling the source code. GE can now leverage the huge Java community.  Undeniably the best virtual machine ever created, hundreds if not thousands of world class developers continually improve, poke, prod and scrutinize all aspects of the Java platform.  As enhancements are made, GE automatically gains access to these. As Magik has little in the way of support for multi-threading, GE will benefit from current and future Java offerings (e.g. lambda expressions) that aim to further facilitate multi-core/multi-threaded application development. As the JVM is available for many more platforms, it broadens the reach of Magik, including the potential to run on a class devices never envisioned just a few short years ago.  For example, Java SE compatible runtime environments are available for popular embedded ARM/Intel/PowerPC configurations that could theoretically host this software too. As compared to other JVM language projects, the Magik integration differs in that it represents a serious commercial entity betting a sizable part of its business on the success of this effort.  Expect to see announcements not only from General Electric, but other organizations as they realize the benefits of utilizing the Java Virtual Machine.

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  • MIX 2010 Covert Operations Day 3

    - by GeekAgilistMercenary
    I rolled over to the Mandalay for breakfast.  There I met a couple guys that were really excited about the new Windows 7 Phone.  They, as I, are also hopeful that the phone really gets a big push and some penetration into the market.  Not because we don’t like any other of the phones, but because this phone is so much better in many ways.  From a developer's perspective creating applications in Windows 7 Mobile will be vastly superior in ease, capabilities, and other aspects.  The architectural, existing code base, examples, and provisions to create things on the 7 Mobile Device are already existing as of RIGHT NOW.  There is no reason, except for fickle market conditions, for this phone to not just explode onto the market.  But alas, I won't hold my breath. Day three keynote had a whole new slew of things provided.  It also seemed that things got a lot more technical on this second keynote.  The oData was one of the very technical bits, yet it included almost no code.  Starting with a Netflix example and all the way to the Codename "Dallas" effort the oData Services provide some expansive possibilities. A mash up going 4 ways was then shown for finding a movie, finding local places to have a viewing, and information about the movie and were to prospectively find and buy additional movie bits.  The display was of course, in a Windows 7 Mobile device with literally a click to view each set of data.  The backend and the front end of this was beautifully smooth. The Dallas Project has a lot of potential for analytics in dashboard and scorecard creation also.  If there is a need or reason to provide data to a vast and wide range of clients, Dallas is a prime example of how to do that. Azure Clouds After the main keynote I checked out (while developing a working WPF & Silverlight Application for work) the session on deploying ASP.NET Applications, services, etc, into the cloud.  The session was pretty good, but I'll admit I got a little unfocused from it a few times.  It is after all hard to do two things at one time. I did take note that the cloud still is a multiple step process for deploying to.  This is a good thing and a bad thing.  There needs to be more checks and verifications when deploying something into the cloud just for technical reasons.  However, I feel that there should be some streamlining to the process.  Going back and forth between web and Visual Studio as the interface also seems kind of clunky.  Deployment should be able to be completed from within Visual Studio in my perspective.  Overall, the cloud is getting more and more impressive in function as well as theory. That's it from me so far on the third day of MIX.  I'll be note taking and studying hard to have more good tidbits to provide. Thanks for reading, if you're curious about more of my writing, check out this original entry at my other blog Agilist Mercenary.

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  • Is This Your Idea of Disaster Recovery?

    - by rickramsey
    Don't just make do with less. Protect what you've got. By, for instance, deploying Oracle Solaris 10 inside a zone cluster. "Wait," you say, "what is a zone cluster?" It is a zone deployed across different physical servers. "Who would do that!" you ask in a mild panic. Why, an upstanding sysadmin citizen interested in protecting his or her employer's investment with appropriate high availability and disaster recovery. If one server gets wiped out by Hurricane Sandy along with pretty much the entire East Coast of the USA, your zone continues to run on the other server(s). Provided you set them up in Edinburgh. This white paper (pdf) explains what a zone cluster is and how to use it. If a white paper reminds you of having to read War and Peace in school, just use this Oracle RAC and Solaris Cluster Cheat Sheet, instead. "But wait!" you exclaim. "I didn't realize Solaris 10 offered zone clusters!" I didn't, either! And in an earlier version of this blog post I said that zone clusters were only available with Oracle Solaris 11. But Karoly Vegh pointed me to the documentation for Oracle Solaris Cluster 3.3, which explains how to manage zone clusters in Oracle Solaris 10. Bite my fist! So, the point I was trying to make is not just that you can run Oracle Solaris 10 zone clusters, but that you can run them in an Oracle Solaris 11 environment. Now let's return to our conversation and pick up where we left off ... "Oh no! Whatever shall I do?" Fear not. Remember how Oracle Solaris 11 lets you create a Solaris 10 branded zone inside a system running Oracle Solaris 11? Well, the Solaris Cluster engineers thought that was a bang-up idea, and decided to extend Oracle Solaris Cluster so that you could run your Solaris 10 applications inside the protective cocoon of an Oracle Solaris 11 zone cluster. Take advantage of the installation improvements and network virtualization capabilities of Oracle Solaris 11 while still running your application on Oracle Solaris 10. You Luddite, you. That capability is in the latest release of Oracle Solaris Cluster, version 4.1, which became available last Friday. "Last Friday! Is it too late to get a copy?" You can still get a free copy from our download center (see below). And, if you'd like to know what other goodies the 4.1 release of Oracle Solaris Cluster provides, see: What's New In Oracle Solaris Cluster 4.1 (pdf) Free download Oracle Solaris Cluster 4.1 (SPARC or x86) Tech Article: How to Upgrade to Oracle Solaris Cluster 4.0, by Tim Read. As always, you can get the latest information about Oracle Solaris Cluster, plus technical how-to articles, documentation, and more from Oracle Solaris Cluster Resource Page for Sysadmins and Developers. And don't forget about the online launch of Oracle Solaris 11.1 and Oracle Solaris Cluster 4.1, scheduled for Nov 7. "I feel so much better, now!" Think nothing of it. That's what we're here for. - Rick Website Newsletter Facebook Twitter

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  • Be the surgeon

    - by Rob Farley
    It’s a phrase I use often, especially when teaching, and I wish I had realised the concept years earlier. (And of course, fits with this month’s T-SQL Tuesday topic, hosted by Argenis Fernandez) When I’m sick enough to go to the doctor, I see a GP. I used to typically see the same guy, but he’s moved on now. However, when he has been able to roughly identify the area of the problem, I get referred to a specialist, sometimes a surgeon. Being a surgeon requires a refined set of skills. It’s why they often don’t like to be called “Doctor”, and prefer the traditional “Mister” (the history is that the doctor used to make the diagnosis, and then hand the patient over to the person who didn’t have a doctorate, but rather was an expert cutter, typically from a background in butchering). But if you ask the surgeon about the pain you have in your leg sometimes, you’ll get told to ask your GP. It’s not that your surgeon isn’t interested – they just don’t know the answer. IT is the same now. That wasn’t something that I really understood when I got out of university. I knew there was a lot to know about IT – I’d just done an honours degree in it. But I also knew that I’d done well in just about all my subjects, and felt like I had a handle on everything. I got into developing, and still felt that having a good level of understanding about every aspect of IT was a good thing. This got me through for the first six or seven years of my career. But then I started to realise that I couldn’t compete. I’d moved into management, and was spending my days running projects, rather than writing code. The kids were getting older. I’d had a bad back injury (ask anyone with chronic pain how it affects  your ability to concentrate, retain information, etc). But most of all, IT was getting larger. I knew kids without lives who knew more than I did. And I felt like I could easily identify people who were better than me in whatever area I could think of. Except writing queries (this was before I discovered technical communities, and people like Paul White and Dave Ballantyne). And so I figured I’d specialise. I wish I’d done it years earlier. Now, I can tell you plenty of people who are better than me at any area you can pick. But there are also more people who might consider listing me in some of their lists too. If I’d stayed the GP, I’d be stuck in management, and finding that there were better managers than me too. If you’re reading this, SQL could well be your thing. But it might not be either. Your thing might not even be in IT. Find out, and then see if you can be a world-beater at it. But it gets even better, because you can find other people to complement the things that you’re not so good at. My company, LobsterPot Solutions, has six people in it at the moment. I’ve hand-picked those six people, along with the one who quit. The great thing about it is that I’ve been able to pick people who don’t necessarily specialise in the same way as me. I don’t write their T-SQL for them – generally they’re good enough at that themselves. But I’m on-hand if needed. Consider Roger Noble, for example. He’s doing stuff in HTML5 and jQuery that I could never dream of doing to create an amazing HTML5 version of PivotViewer. Or Ashley Sewell, a guy who does project management far better than I do. I could go on. My team is brilliant, and I love them to bits. We’re all surgeons, and when we work together, I like to think we’re pretty good! @rob_farley

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  • links for 2010-12-23

    - by Bob Rhubart
    Oracle VM Virtualbox 4.0 extension packs (Wim Coekaerts Blog) Wim Coekaerts describes the the new extension pack in Oracle VM Virtualbox 4.0 and how it's different from 3.2 and earlier releases. (tags: oracle otn virtualization virtualbox) Oracle Fusion Middleware Security: Creating OES SM instances on 64 bit systems "I've already opened a bug on this against OES 10gR3 CP5, but in case anyone else runs into it before it gets fixed I wanted to blog it too. (NOTE: CP5 is when official support was introduced for running OES on a 64 bit system with a 64 bit JVM)" - Chris Johnson (tags: oracle otn fusionmiddleware security) Oracle Enterprise Manager Grid Control: Shared loader directory, RAC and WebLogic Clustering "RAC is optional. Even the load balancer is optional. The feed from the agents also goes to the load balancer on a different port and it is routed to the available management server. In normal case, this is ok." - Porus Homi Havewala (tags: WebLogic oracle otn grid clustering) Magic Web Doctor: Thought Process on Upgrading WebLogic Server to 11g "Upgrading to new versions can be challenging task, but it's done for linear scalability, continuous enhanced availability, efficient manageability and automatic/dynamic infrastructure provisioning at a low cost." - Chintan Patel (tags: oracle otn weblogic upgrading) InfoQ: Using a Service Bus to Connect the Supply Chain Peter Paul van de Beek presents a case study of using a service bus in a supply channel connecting a wholesale supplier with hundreds of retailers, the overall context and challenges faced – including the integration of POS software coming from different software providers-, the solution chosen and its implementation, how it worked out and the lessons learned along the way. (tags: ping.fm) Oracle VM VirtualBox 4.0 is released! - The Fat Bloke Sings The Fat Bloke spreads the news and shares some screenshots.  (tags: oracle otn virtualization virtualbox) Leaks on Wikis: "Corporations...You're Next!" Oracle Desktop Virtualization Can Help. (Oracle's Virtualization Blog) "So what can you do to guard against these types of breaches where there is no outsider (or even insider) intrusion to detect per se, but rather someone with malicious intent is physically walking out the door with data that they are otherwise allowed to access in their daily work?" - Adam Hawley (tags: oracle otn virtualization security) OTN ArchBeat Podcast Guest Roster As the OTN ArchBeat Podcast enters its third year, it's time to acknowledge the invaluable contributions of the guests who have participated in ArchBeat programs. Check out this who's who of ArchBeat podcast panelists, with links to their respective interviews and more. (tags: oracle otn oracleace podcast archbeat) Show Notes: Architects in the Cloud (ArchBeat) Now available! Part 2 (of 4) of the ArchBeat interview with Stephen G. Bennett and Archie Reed, the authors of "Silver Clouds, Dark Linings: A Concise Guide to Cloud Computing." (tags: oracle otn podcast cloud) A Cautionary Tale About Multi-Source JNDI Configuration (Scott Nelson's Portal Productivity Ponderings) "I ran into this issue after reading that p13nDataSource and cgDataSource-NonXA should not be configured as multi-source. There were some issues changing them to use the basic JDBC connection string and when rolling back to the bad configuration the server went 'Boom.'" - Scott Nelson (tags: weblogic jdbc oracle jndi)

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  • Two Candidates + One Job = Two Different Outcomes

    - by david.talamelli
    Recruiters have always headhunted (sidenote: I do not like this word, in general I think the type of people who use the phrase “headhunting” are the ones who are trying to sound more important than what they likely are). Any serious Recruiter engages in direct recruiting activity, it is part and parcel of the business it is not something unique. With the uptake in Social Media the past 4-5 years, we have seen an increase in the number of Recruiters proactively reaching out to people about job opportunities. We have also seen this activity increase across all levels of hire, from help desk roles to C-Level Executives. While getting approached about a role can be a nice boost to a person’s ego, do not let it give you an inflated sense of entitlement. It is The way that people handle themselves during these calls and subsequent interviews will have a large impact on their potential to land that job. Last week I spoke to two very different candidates, both about the same position and both with very different outcomes. On paper, Candidate #1 looked fantastic; they ticked many of the boxes that we were looking for. The person is working at global IT company and working in a similar role as the one we were hiring for but not in as senior as the role we had. This role would have been the perfect step to getting involved in more complex work for the person. Candidate #2 had less polished IT experience, ticked some of the boxes we were looking for and on paper in comparison to Candidate #1 was not as close a fit as Candidate #1 was. It seemed like I was comparing apples and oranges. After speaking to both candidates it turns out I was comparing apples and oranges except the person better suited for our role was not the one I was expecting it would be. The first candidate on paper looked great – they had the experience we were looking for and appeared to be just right for the role, but after talking to them, they gave me the impression that they thought the world owed them. The impression I was left with was that they did not equate success with hard work, they seemed more interested in “what is in it for me”. Rather than having a proper conversation with me, I was often cut off and asked to hurry it up when explaining our business, what we are doing, etc... . This person seemed more interested in the job title and money than how rather than think about ways to make the role successful. Candidate #2 who had limited experience, made up for any perceived lack of experience and them some with a demonstrated motivation to succeed and do the things needed to make that happen. Candidate #2 made a great first impression, they did not seem afraid of hard work and demonstrated a “team player” attitude. In talking to them they kept me engaged, listened and asked thoughtful questions that made me think this is the type of person who creates their own luck and who would thrive in a place like Oracle. Skills, capabilities, experience and a good resume can certainly get your foot in the door, but the wrong attitude or approach to work can close those opportunities just as easily. On the other hand, hard work, effort and a genuine work ethic may help open those doors that would otherwise closed for you. A resume with all the credentials gets you in the front door but that is just the beginning of the process. It is not how we start the race that is important, it’s how things end that matter most.

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  • Big Data – Interacting with Hadoop – What is Sqoop? – What is Zookeeper? – Day 17 of 21

    - by Pinal Dave
    In yesterday’s blog post we learned the importance of the Pig and Pig Latin in Big Data Story. In this article we will understand what is Sqoop and Zookeeper in Big Data Story. There are two most important components one should learn when learning about interacting with Hadoop – Sqoop and Zookper. What is Sqoop? Most of the business stores their data in RDBMS as well as other data warehouse solutions. They need a way to move data to the Hadoop system to do various processing and return it back to RDBMS from Hadoop system. The data movement can happen in real time or at various intervals in bulk. We need a tool which can help us move this data from SQL to Hadoop and from Hadoop to SQL. Sqoop (SQL to Hadoop) is such a tool which extract data from non-Hadoop data sources and transform them into the format which Hadoop can use it and later it loads them into HDFS. Essentially it is ETL tool where it Extracts, Transform and Load from SQL to Hadoop. The best part is that it also does extract data from Hadoop and loads them to Non-SQL (or RDBMS) data stores. Essentially, Sqoop is a command line tool which does SQL to Hadoop and Hadoop to SQL. It is a command line interpreter. It creates MapReduce job behinds the scene to import data from an external database to HDFS. It is very effective and easy to learn tool for nonprogrammers. What is Zookeeper? ZooKeeper is a centralized service for maintaining configuration information, naming, providing distributed synchronization, and providing group services. In other words Zookeeper is a replicated synchronization service with eventual consistency. In simpler words – in Hadoop cluster there are many different nodes and one node is master. Let us assume that master node fails due to any reason. In this case, the role of the master node has to be transferred to a different node. The main role of the master node is managing the writers as that task requires persistence in order of writing. In this kind of scenario Zookeeper will assign new master node and make sure that Hadoop cluster performs without any glitch. Zookeeper is the Hadoop’s method of coordinating all the elements of these distributed systems. Here are few of the tasks which Zookeepr is responsible for. Zookeeper manages the entire workflow of starting and stopping various nodes in the Hadoop’s cluster. In Hadoop cluster when any processes need certain configuration to complete the task. Zookeeper makes sure that certain node gets necessary configuration consistently. In case of the master node fails, Zookeepr can assign new master node and make sure cluster works as expected. There many other tasks Zookeeper performance when it is about Hadoop cluster and communication. Basically without the help of Zookeeper it is not possible to design any new fault tolerant distributed application. Tomorrow In tomorrow’s blog post we will discuss about very important components of the Big Data Ecosystem – Big Data Analytics. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: Big Data, PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL

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  • Clever memory usage through the years

    - by Ben Emmett
    A friend and I were recently talking about the really clever tricks people have used to get the most out of memory. I thought I’d share my favorites, and would love to hear yours too! Interleaving on drum memory Back in the ye olde days before I’d been born (we’re talking the 50s / 60s here), working memory commonly took the form of rotating magnetic drums. These would spin at a constant speed, and a fixed head would read from memory when the correct part of the drum passed it by, a bit like a primitive platter disk. Because each revolution took a few milliseconds, programmers took to manually arranging information non-sequentially on the drum, timing when an instruction or memory address would need to be accessed, then spacing information accordingly around the edge of the drum, thus reducing the access delay. Similar techniques were still used on hard disks and floppy disks into the 90s, but have become irrelevant with modern disk technologies. The Hashlife algorithm Conway’s Game of Life has attracted numerous implementations over the years, but Bill Gosper’s Hashlife algorithm is particularly impressive. Taking advantage of the repetitive nature of many cellular automata, it uses a quadtree structure to store the hashes of pieces of the overall grid. Over time there are fewer and fewer new structures which need to be evaluated, so it starts to run faster with larger grids, drastically outperforming other algorithms both in terms of speed and the size of grid which can be simulated. The actual amount of memory used is huge, but it’s used in a clever way, so makes the list . Elite’s procedural generation Ok, so this isn’t exactly a memory optimization – more a storage optimization – but it gets an honorable mention anyway. When writing Elite, David Braben and Ian Bell wanted to build a rich world which gamers could explore, but their 22K memory was something of a limitation (for comparison that’s about the size of my avatar picture at the top of this page). They procedurally generated all the characteristics of the 2048 planets in their virtual universe, including the names, which were stitched together using a lookup table of parts of names. In fact the original plans were for 2^52 planets, but it was decided that that was probably too many. Oh, and they did that all in assembly language. Other games of the time used similar techniques too – The Sentinel’s landscape generation algorithm being another example. Modern Garbage Collectors Garbage collection in managed languages like Java and .NET ensures that most of the time, developers stop needing to care about how they use and clean up memory as the garbage collector handles it automatically. Achieving this without killing performance is a near-miraculous feet of software engineering. Much like when learning chemistry, you find that every time you think you understand how the garbage collector works, it turns out to be a mere simplification; that there are yet more complexities and heuristics to help it run efficiently. Of course introducing memory problems is still possible (and there are tools like our memory profiler to help if that happens to you) but they’re much, much rarer. A cautionary note In the examples above, there were good and well understood reasons for the optimizations, but cunningly optimized code has usually had to trade away readability and maintainability to achieve its gains. Trying to optimize memory usage without being pretty confident that there’s actually a problem is doing it wrong. So what have I missed? Tell me about the ingenious (or stupid) tricks you’ve seen people use. Ben

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  • As a person getting into mobile development, what's the best mobile platform in terms of profitability? [closed]

    - by Kyle Loman
    I realize this question can range very far so would love to hear any and all opinions on this. However, I'll be honest and say that I have been thinking of this in terms of most profitable. I know how this may sound either way but this is one of my main sticking points. I realize that I'm not guaranteed a single cent and success is never guaranteed but I'm going into this with the thought of making something out of it both financially and also for my own interest. I know that iOS gets a lot of attention on this front but Android commands a lot more market share. However, I know there are drawbacks to Android too, whether it's in the actual development process and programming (though I've heard conflicting reports on this, such as how easy/difficult it is for to address screen res in different devices) or the app ecosystem being flooded. But iOS's app ecosystem has been described as too saturated and harder to compete in for that reason. Since Windows Phone has fewer apps than both of those two, that might be the best place to start in order to be closer to the ground floor of the store and be noticed more? Less saturation = better chances of sales or differentiating? Something like the gold rush during the first years of the iOS App Store (not exactly but at least in concept)? Would it be that despite fewer users on the platform, there's more exposure due to less competition so that may translate to better success at sales? Plus, I know MS is in it for the long haul so I'm not too fearful of something like WebOS going away. Obviously RIM isn't very popular nowadays but I read a recent article that says Blackberry actually has the apps that make the most money, any thoughts on that: http://gigaom.com/mobile/which-mobile-oss-apps-make-most-money-surprise-its-blackberry/ Again, this is all I've heard or known about so if there's anything to add or correct here, please do. In addition, this has actually affected my next personal phone upgrade. I'm eligible for a carrier discount now and I've had my eye on the iPhone 5. However, the Lumia 920 is the one I'm holding out for and I'm open to trying an Android but I'm not sure I can wait that long for any new Nexus or even the Razr HD. Even the new Lumia in November is making me antsy, I'm so close to just getting an iPhone 5. But when I say this has affected my phone choice, I'd want to be able to carry the apps I write with me so that I'm able to pull my phone out to show people without having to carry around a second device to do so. So that's why I'd like to make my personal phone match the main platform I'm developing for. Of course, I will likely expand to other platforms if I gain any decent success but the one I target now would serve well as my personal phone I carry around so that I can use it as a marketing tool, in a sense, showing people my apps if the opportunity presents itself. So what's the best mobile platform to choose, and especially in regards to most lucrative? As said previously, this would influence my personal phone choice greatly. Thanks in advance and I hope this isn't taken the wrong way - I understand there are trade-offs and other factors that may balance this out but making some revenue is key among that. For some background, I have done software development and know programming language concepts so I'm not entirely new to it and I do get the notion of being familiar with these things so that I can translate this skill among a variety of languages but I'm currently just having difficulty choosing my first main mobile platform based on the criteria I've outlined above.

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  • Why Is Hibernation Still Used?

    - by Jason Fitzpatrick
    With the increased prevalence of fast solid-state hard drives, why do we still have system hibernation? Today’s Question & Answer session comes to us courtesy of SuperUser—a subdivision of Stack Exchange, a community-driven grouping of Q&A web sites. The Question SuperUser reader Moses wants to know why he should use hibernate on a desktop machine: I’ve never quite understood the original purpose of the Hibernation power state in Windows. I understand how it works, what processes take place, and what happens when you boot back up from Hibernate, but I’ve never truly understood why it’s used. With today’s technology, most notably with SSDs, RAM and CPUs becoming faster and faster, a cold boot on a clean/efficient Windows installation can be pretty fast (for some people, mere seconds from pushing the power button). Standby is even faster, sometimes instantaneous. Even SATA drives from 5-6 years ago can accomplish these fast boot times. Hibernation seems pointless to me [on desktop computers] when modern technology is considered, but perhaps there are applications that I’m not considering. What was the original purpose behind hibernation, and why do people still use it? Quite a few people use hibernate, so what is Moses missing in the big picture? The Answer SuperUser contributor Vignesh4304 writes: Normally hibernate mode saves your computer’s memory, this includes for example open documents and running applications, to your hard disk and shuts down the computer, it uses zero power. Once the computer is powered back on, it will resume everything where you left off. You can use this mode if you won’t be using the laptop/desktop for an extended period of time, and you don’t want to close your documents. Simple Usage And Purpose: Save electric power and resuming of documents. In simple terms this comment serves nice e.g (i.e. you will sleep but your memories are still present). Why it’s used: Let me describe one sample scenario. Imagine your battery is low on power in your laptop, and you are working on important projects on your machine. You can switch to hibernate mode – it will result your documents being saved, and when you power on, the actual state of application gets restored. Its main usage is like an emergency shutdown with an auto-resume of your documents. MagicAndre1981 highlights the reason we use hibernate everyday: Because it saves the status of all running programs. I leave all my programs open and can resume working the next day very easily. Doing a real boot would require to start all programs again, load all the same files into those programs, get to the same place that I was at before, and put all my windows in exactly the same place. Hibernating saves a lot of work pulling these things back up again. It’s not unusual to find computers around the office here that have been hibernated day in and day out for months without an actual full system shutdown and restart. It’s enormously convenient to freeze your work space at the exact moment you stopped working and to turn right around and resume there the next morning. Have something to add to the explanation? Sound off in the the comments. Want to read more answers from other tech-savvy Stack Exchange users? Check out the full discussion thread here.     

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  • Oracle Retail Mobile Point-of-Service

    - by David Dorf
    When most people discuss mobile in retail, they immediately go to shopping applications.  While I agree the consumer side of mobile is huge, I believe its also important to arm store associates with mobile tools.  There are around a dozen major roll-outs of mobile POS to chain retailers, and all have been successful.  This does not, however, signal the demise of traditional registers.  Retailers will adopt mobile POS slowly and reduce the number of fixed registers over time, but there's likely to be a combination of both for the foreseeable future.  Even Apple retains at least one fixed register in every store, you just have to know where to look. The business benefits for mobile POS are pretty straightforward: 1. Faster checkout.  Walmart's CFO recently reported that for every second they shave off the average transaction time, they can potentially save $12M a year in labor.  I think its more likely that labor will be redeployed to enhance the customer experience. 2. Smarter associates.  The sales associates on the floor need the same access to information that consumers have, if not more.  They need ready access to product details, reviews, inventory, etc. to meet consumer expectations.  In a recent study, 40% of consumers said a savvy store associate can impact their final product selection more than a website. 3. Lower costs.  Mobile POS hardware (iPod touch + sled) costs about a fifth of fixed registers, not to mention the reclaimed space that can be used for product displays. But almost all Mobile POS solutions can claim those benefits equally.  Where there's differentiation is on the technical side.  Oracle recently announced availability of the Oracle Retail Mobile Point-of-Service, and it has three big technology advantages in the market: 1. Portable. We used a popular open-source component called PhoneGap that abstracts the app from the underlying OS and hardware so that iOS, Android, and other platforms could be supported.  Further, we used Web technologies such as HTML5 and JavaScript, which are commonly known by many programmers, as opposed to ObjectiveC which is more difficult to find.  The screen can adjust to different form-factors and sizes, just like you see with browsers.  In the future when a new, zippy device gets released, retailers will have the option to move to that device more easily than if they used a native app. 2. Flexible.  Our Mobile POS is free with the Oracle Retail Point-of-Service product.  Retailers can use any combination of fixed and mobile registers, and those ratios can change as required.  Perhaps start with 1 mobile and 4 fixed per store, then transition over time to 4 mobile and 1 fixed without any additional software licenses.  Our scalable solution supports lots of combinations. 3. Consistent.  Because our Mobile POS is fully integrated to our traditional POS, the same business logic is reused.  Third-party Mobile POS solutions often handle pricing, promotions, and tax calculations separately leading to possible inconsistencies within the store.  That won't happen with Oracle's solution. For many retailers, Mobile POS can lower costs, increase customer service, and generally enhance a consumer's in-store experience.  Apple led the way, but lots of other retailers are discovering the many benefits of adding mobile capabilities in their stores.  Just be sure to examine both the business and technology benefits so you get the most value from your solution for the longest period of time.

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  • Silverlight Cream for January 15, 2011 -- #1028

    - by Dave Campbell
    Note to #1024 Swag Winners: I'm sending emails to the vendors Sunday night, thanks for your patience (a few of you have not contacted me yet) In this Issue: Ezequiel Jadib, Daniel Egan(-2-), Page Brooks, Jason Zander, Andrej Tozon, Marlon Grech, Jonathan van de Veen, Walt Ritscher, Jesse Liberty, Jeremy Likness, Sacha Barber, William E. Burrows, and WindowsPhoneGeek. Above the Fold: Silverlight: "Building a Radar Control in Silverlight - Part 1" Page Brooks WP7: "Tutorial: Dynamic Tile Push Notification for Windows Phone 7" Jason Zander Training: "WP7 Unleashed Session I–Hands on Labs" Daniel Egan From SilverlightCream.com: Silverlight Rough Cut Editor SP1 Released Ezequiel Jadib has an announcement about the Rough Cut Editor SP1 release, and he walks you through the content, installation and a bit of the initial use. WP7 Unleashed Session I–Hands on Labs Daniel Egan posted Part 1 of 3 of a new WP7 HOL ... video online and material to download... get 'em while they're hot! WP7 Saving to Media Library Daniel Egan has another post up as well on saving an image to the media library... not the update from Tim Heuer... all good info Building a Radar Control in Silverlight - Part 1 This freakin' cool post from Page Brooks is the first one of a series on building a 'Radar Control' in Silverlight ... seriously, go to the bottom and run the demo... I pretty much guarantee you'll take the next link which is download the code... don't forget to read the article too! Tutorial: Dynamic Tile Push Notification for Windows Phone 7 Jason Zander has a nice-looking tutorial up on dynamic tile notifications... good diagrams and discussion and plenty of code. Reactive.buffering.from event. Andrej Tozon is continuing his Reactive Extensions posts with this one on buffering: BufferWithTime and BufferWIthCount ... good stuff, good write-up, and the start of a WP7 game? MEFedMVVM with PRISM 4 Marlon Grech combines his MEFedMVVM with Prism 4, and says it was easy... check out the post and the code. Adventures while building a Silverlight Enterprise application part #40 Jonathan van de Veen has a discussion up about things you need to pay attention to as your project gets close to first deployment... lots of good information to think about Silverlight or not. Customize Windows 7 Preview pane for XAML files Walt Ritscher has a (very easy) XAML extension for Windows 7 that allows previewing of XAML files in an explorer window... as our UK friends say "Brilliant!" Entity Framework Code-First, oData & Windows Phone Client From the never-ending stream of posts that is Jesse Liberty comes this one on EF Code-First... so Jesse's describing Code-First and OData all wrapped up about a WP7 app Sterling Silverlight and Windows Phone 7 Database Triggers and Auto-Identity Sterling and Database Triggers sitting in a tree... woot for WP7 from Jeremy Likness... provides database solutions including Validation, Data-specific concerns such as 'last modified', and post-save processing ... all good, Jeremy! A Look At Fluent APIs Sacha Barber has a great post up that isn't necessarily Silverlight, but is it? ... we've been hearing a lot about Fluent APIs... read on to see what the buzz is. Windows Phone 7 - Part 3 - Final Application William E. Burrows has Part 3 of his WP7 tutorial series up... this one completing the Golf Handicap app by giving the user the ability to manage scores. User Control vs Custom Control in Silverlight for WP7 WindowsPhoneGeek has a great diagram and description-filled post up on User Controls and Custom Controls in WP7... good external links too. Stay in the 'Light! Twitter SilverlightNews | Twitter WynApse | WynApse.com | Tagged Posts | SilverlightCream Join me @ SilverlightCream | Phoenix Silverlight User Group Technorati Tags: Silverlight    Silverlight 3    Silverlight 4    Windows Phone MIX10

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  • XNA RenderTarget2D Sample

    - by Michael B. McLaughlin
    I remember being scared of render targets when I first started with XNA. They seemed like weird magic and I didn’t understand them at all. There’s nothing to be frightened of, though, and they are pretty easy to learn how to use. The first thing you need to know is that when you’re drawing in XNA, you aren’t actually drawing to the screen. Instead you’re drawing to this thing called the “back buffer”. Internally, XNA maintains two sections of graphics memory. Each one is exactly the same size as the other and has all the same properties (such as surface format, whether there’s a depth buffer and/or a stencil buffer, and so on). XNA flips between these two sections of memory every update-draw cycle. So while you are drawing to one, it’s busy drawing the other one on the screen. Then the current update-draw cycle ends, it flips, and the section you were just drawing to gets drawn to the screen while the one that was being drawn to the screen before is now the one you’ll be drawing on. This is what’s meant by “double buffering”. If you drew directly to the screen, the player would see all of those draws taking place as they happened and that would look odd and not very good at all. Those two sections of graphics memory are render targets. All a render target is, is a section of graphics memory to which things can be drawn. In addition to the two that XNA maintains automatically, you can also create and set your own using RenderTarget2D and GraphicsDevice.SetRenderTarget. Using render targets lets you do all sorts of neat post-processing effects (like bloom) to make your game look cooler. It also just lets you do things like motion blur and lets you create mirrors in 3D games. There are quite a lot of things that render targets let you do. To go along with this post, I wrote up a simple sample for how to create and use a RenderTarget2D. It’s available under the terms of the Microsoft Public License and is available for download on my website here: http://www.bobtacoindustries.com/developers/utils/RenderTarget2DSample.zip . Other than the ‘using’ statements, every line is commented in detail so that it should (hopefully) be easy to follow along with and understand. If you have any questions, leave a comment here or drop me a line on Twitter. One last note. While creating the sample I came across an interesting quirk. If you start by creating a Windows Game, and then make a copy for Windows Phone 7, the drop-down that lets you choose between drawing to a WP7 device and the WP7 emulator stays grayed-out. To resolve this, you need to right click on the Windows Phone 7 version in the Solution Explorer, and choose “Set as StartUp Project”. The bar will then become active, letting you change the target you which to deploy to. If you want another version to be the one that starts up when you press F5 to start debugging, just go and right-click on that version and choose “Set as StartUp Project” for it once you’ve set the WP7 target (device or emulator) that you want.

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  • C++ OpenGL wireframe cube rendering blank

    - by caleb.breckon
    I'm just trying to draw a bunch of lines that make up a "cube". I can't for the life of me figure out why this is producing a black screen. The debugger does not break at any point. I'm sure it's a problem with my pointers, as I'm only decent at them in regular c++ and in OpenGL it gets even worse. const char* vertexSource = "#version 150\n" "in vec3 position;" "void main() {" " gl_Position = vec4(position, 1.0);" "}"; const char* fragmentSource = "#version 150\n" "out vec4 outColor;" "void main() {" " outColor = vec4(1.0, 1.0, 1.0, 1.0);" "}"; int main() { initializeGLFW(); // Initialize GLEW glewExperimental = GL_TRUE; glewInit(); // Create Vertex Array Object GLuint vao; glGenVertexArrays(1, &vao); glBindVertexArray(vao); // Create a Vertex Buffer Object and copy the vertex data to it GLuint vbo; glGenBuffers( 1, &vbo ); float vertices[] = { 1.0f, 1.0f, 1.0f, // Vertex 0 (X, Y, Z) -1.0f, 1.0f, 1.0f, // Vertex 1 (X, Y, Z) -1.0f, -1.0f, 1.0f, // Vertex 2 (X, Y, Z) 1.0f, -1.0f, 1.0f, // Vertex 3 (X, Y, Z) 1.0f, 1.0f, -1.0f, // Vertex 4 (X, Y, Z) -1.0f, 1.0f, -1.0f, // Vertex 5 (X, Y, Z) -1.0f, -1.0f, -1.0f, // Vertex 6 (X, Y, Z) 1.0f, -1.0f, -1.0f // Vertex 7 (X, Y, Z) }; GLuint indices[] = { 0, 1, 1, 2, 2, 3, 3, 0, 4, 5, 5, 6, 6, 7, 7, 4, 0, 4, 1, 5, 2, 6, 3, 7 }; glBindBuffer( GL_ARRAY_BUFFER, vbo ); glBufferData( GL_ARRAY_BUFFER, sizeof( vertices ), vertices, GL_STATIC_DRAW ); //glBindBuffer( GL_ELEMENT_ARRAY_BUFFER, vbo); //glBufferData( GL_ELEMENT_ARRAY_BUFFER, sizeof( indices ), indices, GL_STATIC_DRAW ); // Create and compile the vertex shader GLuint vertexShader = glCreateShader( GL_VERTEX_SHADER ); glShaderSource( vertexShader, 1, &vertexSource, NULL ); glCompileShader( vertexShader ); // Create and compile the fragment shader GLuint fragmentShader = glCreateShader( GL_FRAGMENT_SHADER ); glShaderSource( fragmentShader, 1, &fragmentSource, NULL ); glCompileShader( fragmentShader ); // Link the vertex and fragment shader into a shader program GLuint shaderProgram = glCreateProgram(); glAttachShader( shaderProgram, vertexShader ); glAttachShader( shaderProgram, fragmentShader ); glBindFragDataLocation( shaderProgram, 0, "outColor" ); glLinkProgram (shaderProgram); glUseProgram( shaderProgram); // Specify the layout of the vertex data GLint posAttrib = glGetAttribLocation( shaderProgram, "position" ); glEnableVertexAttribArray( posAttrib ); glVertexAttribPointer( posAttrib, 3, GL_FLOAT, GL_FALSE, 0, 0 ); // Main loop while(glfwGetWindowParam(GLFW_OPENED)) { // Clear the screen to black glClearColor( 0.0f, 0.0f, 0.0f, 1.0f ); glClear( GL_COLOR_BUFFER_BIT ); // Draw lines from 2 vertices glDrawElements(GL_LINES, sizeof(indices), GL_UNSIGNED_INT, indices ); // Swap buffers glfwSwapBuffers(); } // Clean up glDeleteProgram( shaderProgram ); glDeleteShader( fragmentShader ); glDeleteShader( vertexShader ); //glDeleteBuffers( 1, &ebo ); glDeleteBuffers( 1, &vbo ); glDeleteVertexArrays( 1, &vao ); glfwTerminate(); exit( EXIT_SUCCESS ); }

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