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  • Microsoft Introduces WebMatrix

    - by Rick Strahl
    originally published in CoDe Magazine Editorial Microsoft recently released the first CTP of a new development environment called WebMatrix, which along with some of its supporting technologies are squarely aimed at making the Microsoft Web Platform more approachable for first-time developers and hobbyists. But in the process, it also provides some updated technologies that can make life easier for existing .NET developers. Let’s face it: ASP.NET development isn’t exactly trivial unless you already have a fair bit of familiarity with sophisticated development practices. Stick a non-developer in front of Visual Studio .NET or even the Visual Web Developer Express edition and it’s not likely that the person in front of the screen will be very productive or feel inspired. Yet other technologies like PHP and even classic ASP did provide the ability for non-developers and hobbyists to become reasonably proficient in creating basic web content quickly and efficiently. WebMatrix appears to be Microsoft’s attempt to bring back some of that simplicity with a number of technologies and tools. The key is to provide a friendly and fully self-contained development environment that provides all the tools needed to build an application in one place, as well as tools that allow publishing of content and databases easily to the web server. WebMatrix is made up of several components and technologies: IIS Developer Express IIS Developer Express is a new, self-contained development web server that is fully compatible with IIS 7.5 and based on the same codebase that IIS 7.5 uses. This new development server replaces the much less compatible Cassini web server that’s been used in Visual Studio and the Express editions. IIS Express addresses a few shortcomings of the Cassini server such as the inability to serve custom ISAPI extensions (i.e., things like PHP or ASP classic for example), as well as not supporting advanced authentication. IIS Developer Express provides most of the IIS 7.5 feature set providing much better compatibility between development and live deployment scenarios. SQL Server Compact 4.0 Database access is a key component for most web-driven applications, but on the Microsoft stack this has mostly meant you have to use SQL Server or SQL Server Express. SQL Server Compact is not new-it’s been around for a few years, but it’s been severely hobbled in the past by terrible tool support and the inability to support more than a single connection in Microsoft’s attempt to avoid losing SQL Server licensing. The new release of SQL Server Compact 4.0 supports multiple connections and you can run it in ASP.NET web applications simply by installing an assembly into the bin folder of the web application. In effect, you don’t have to install a special system configuration to run SQL Compact as it is a drop-in database engine: Copy the small assembly into your BIN folder (or from the GAC if installed fully), create a connection string against a local file-based database file, and then start firing SQL requests. Additionally WebMatrix includes nice tools to edit the database tables and files, along with tools to easily upsize (and hopefully downsize in the future) to full SQL Server. This is a big win, pending compatibility and performance limits. In my simple testing the data engine performed well enough for small data sets. This is not only useful for web applications, but also for desktop applications for which a fully installed SQL engine like SQL Server would be overkill. Having a local data store in those applications that can potentially be accessed by multiple users is a welcome feature. ASP.NET Razor View Engine What? Yet another native ASP.NET view engine? We already have Web Forms and various different flavors of using that view engine with Web Forms and MVC. Do we really need another? Microsoft thinks so, and Razor is an implementation of a lightweight, script-only view engine. Unlike the Web Forms view engine, Razor works only with inline code, snippets, and markup; therefore, it is more in line with current thinking of what a view engine should represent. There’s no support for a “page model” or any of the other Web Forms features of the full-page framework, but just a lightweight scripting engine that works with plain markup plus embedded expressions and code. The markup syntax for Razor is geared for minimal typing, plus some progressive detection of where a script block/expression starts and ends. This results in a much leaner syntax than the typical ASP.NET Web Forms alligator (<% %>) tags. Razor uses the @ sign plus standard C# (or Visual Basic) block syntax to delineate code snippets and expressions. Here’s a very simple example of what Razor markup looks like along with some comment annotations: <!DOCTYPE html> <html>     <head>         <title></title>     </head>     <body>     <h1>Razor Test</h1>          <!-- simple expressions -->     @DateTime.Now     <hr />     <!-- method expressions -->     @DateTime.Now.ToString("T")          <!-- code blocks -->     @{         List<string> names = new List<string>();         names.Add("Rick");         names.Add("Markus");         names.Add("Claudio");         names.Add("Kevin");     }          <!-- structured block statements -->     <ul>     @foreach(string name in names){             <li>@name</li>     }     </ul>           <!-- Conditional code -->        @if(true) {                        <!-- Literal Text embedding in code -->        <text>         true        </text>;    }    else    {        <!-- Literal Text embedding in code -->       <text>       false       </text>;    }    </body> </html> Like the Web Forms view engine, Razor parses pages into code, and then executes that run-time compiled code. Effectively a “page” becomes a code file with markup becoming literal text written into the Response stream, code snippets becoming raw code, and expressions being written out with Response.Write(). The code generated from Razor doesn’t look much different from similar Web Forms code that only uses script tags; so although the syntax may look different, the operational model is fairly similar to the Web Forms engine minus the overhead of the large Page object model. However, there are differences: -Razor pages are based on a new base class, Microsoft.WebPages.WebPage, which is hosted in the Microsoft.WebPages assembly that houses all the Razor engine parsing and processing logic. Browsing through the assembly (in the generated ASP.NET Temporary Files folder or GAC) will give you a good idea of the functionality that Razor provides. If you look closely, a lot of the feature set matches ASP.NET MVC’s view implementation as well as many of the helper classes found in MVC. It’s not hard to guess the motivation for this sort of view engine: For beginning developers the simple markup syntax is easier to work with, although you obviously still need to have some understanding of the .NET Framework in order to create dynamic content. The syntax is easier to read and grok and much shorter to type than ASP.NET alligator tags (<% %>) and also easier to understand aesthetically what’s happening in the markup code. Razor also is a better fit for Microsoft’s vision of ASP.NET MVC: It’s a new view engine without the baggage of Web Forms attached to it. The engine is more lightweight since it doesn’t carry all the features and object model of Web Forms with it and it can be instantiated directly outside of the HTTP environment, which has been rather tricky to do for the Web Forms view engine. Having a standalone script parser is a huge win for other applications as well – it makes it much easier to create script or meta driven output generators for many types of applications from code/screen generators, to simple form letters to data merging applications with user customizability. For me personally this is very useful side effect and who knows maybe Microsoft will actually standardize they’re scripting engines (die T4 die!) on this engine. Razor also better fits the “view-based” approach where the view is supposed to be mostly a visual representation that doesn’t hold much, if any, code. While you can still use code, the code you do write has to be self-contained. Overall I wouldn’t be surprised if Razor will become the new standard view engine for MVC in the future – and in fact there have been announcements recently that Razor will become the default script engine in ASP.NET MVC 3.0. Razor can also be used in existing Web Forms and MVC applications, although that’s not working currently unless you manually configure the script mappings and add the appropriate assemblies. It’s possible to do it, but it’s probably better to wait until Microsoft releases official support for Razor scripts in Visual Studio. Once that happens, you can simply drop .cshtml and .vbhtml pages into an existing ASP.NET project and they will work side by side with classic ASP.NET pages. WebMatrix Development Environment To tie all of these three technologies together, Microsoft is shipping WebMatrix with an integrated development environment. An integrated gallery manager makes it easy to download and load existing projects, and then extend them with custom functionality. It seems to be a prominent goal to provide community-oriented content that can act as a starting point, be it via a custom templates or a complete standard application. The IDE includes a project manager that works with a single project and provides an integrated IDE/editor for editing the .cshtml and .vbhtml pages. A run button allows you to quickly run pages in the project manager in a variety of browsers. There’s no debugging support for code at this time. Note that Razor pages don’t require explicit compilation, so making a change, saving, and then refreshing your page in the browser is all that’s needed to see changes while testing an application locally. It’s essentially using the auto-compiling Web Project that was introduced with .NET 2.0. All code is compiled during run time into dynamically created assemblies in the ASP.NET temp folder. WebMatrix also has PHP Editing support with syntax highlighting. You can load various PHP-based applications from the WebMatrix Web Gallery directly into the IDE. Most of the Web Gallery applications are ready to install and run without further configuration, with Wizards taking you through installation of tools, dependencies, and configuration of the database as needed. WebMatrix leverages the Web Platform installer to pull the pieces down from websites in a tight integration of tools that worked nicely for the four or five applications I tried this out on. Click a couple of check boxes and fill in a few simple configuration options and you end up with a running application that’s ready to be customized. Nice! You can easily deploy completed applications via WebDeploy (to an IIS server) or FTP directly from within the development environment. The deploy tool also can handle automatically uploading and installing the database and all related assemblies required, making deployment a simple one-click install step. Simplified Database Access The IDE contains a database editor that can edit SQL Compact and SQL Server databases. There is also a Database helper class that facilitates database access by providing easy-to-use, high-level query execution and iteration methods: @{       var db = Database.OpenFile("FirstApp.sdf");     string sql = "select * from customers where Id > @0"; } <ul> @foreach(var row in db.Query(sql,1)){         <li>@row.FirstName @row.LastName</li> } </ul> The query function takes a SQL statement plus any number of positional (@0,@1 etc.) SQL parameters by simple values. The result is returned as a collection of rows which in turn have a row object with dynamic properties for each of the columns giving easy (though untyped) access to each of the fields. Likewise Execute and ExecuteNonQuery allow execution of more complex queries using similar parameter passing schemes. Note these queries use string-based queries rather than LINQ or Entity Framework’s strongly typed LINQ queries. While this may seem like a step back, it’s also in line with the expectations of non .NET script developers who are quite used to writing and using SQL strings in code rather than using OR/M frameworks. The only question is why was something not included from the beginning in .NET and Microsoft made developers build custom implementations of these basic building blocks. The implementation looks a lot like a DataTable-style data access mechanism, but to be fair, this is a common approach in scripting languages. This type of syntax that uses simple, static, data object methods to perform simple data tasks with one line of code are common in scripting languages and are a good match for folks working in PHP/Python, etc. Seems like Microsoft has taken great advantage of .NET 4.0’s dynamic typing to provide this sort of interface for row iteration where each row has properties for each field. FWIW, all the examples demonstrate using local SQL Compact files - I was unable to get a SQL Server connection string to work with the Database class (the connection string wasn’t accepted). However, since the code in the page is still plain old .NET, you can easily use standard ADO.NET code or even LINQ or Entity Framework models that are created outside of WebMatrix in separate assemblies as required. The good the bad the obnoxious - It’s still .NET The beauty (or curse depending on how you look at it :)) of Razor and the compilation model is that, behind it all, it’s still .NET. Although the syntax may look foreign, it’s still all .NET behind the scenes. You can easily access existing tools, helpers, and utilities simply by adding them to the project as references or to the bin folder. Razor automatically recognizes any assembly reference from assemblies in the bin folder. In the default configuration, Microsoft provides a host of helper functions in a Microsoft.WebPages assembly (check it out in the ASP.NET temp folder for your application), which includes a host of HTML Helpers. If you’ve used ASP.NET MVC before, a lot of the helpers should look familiar. Documentation at the moment is sketchy-there’s a very rough API reference you can check out here: http://www.asp.net/webmatrix/tutorials/asp-net-web-pages-api-reference Who needs WebMatrix? Uhm… good Question Clearly Microsoft is trying hard to create an environment with WebMatrix that is easy to use for newbie developers. The goal seems to be simplicity in providing a minimal development environment and an easy-to-use script engine/language that makes it easy to get started with. There’s also some focus on community features that can be used as starting points, such as Web Gallery applications and templates. The community features in particular are very nice and something that would be nice to eventually see in Visual Studio as well. The question is whether this is too little too late. Developers who have been clamoring for a simpler development environment on the .NET stack have mostly left for other simpler platforms like PHP or Python which are catering to the down and dirty developer. Microsoft will be hard pressed to win those folks-and other hardcore PHP developers-back. Regardless of how much you dress up a script engine fronted by the .NET Framework, it’s still the .NET Framework and all the complexity that drives it. While .NET is a fine solution in its breadth and features once you get a basic handle on the core features, the bar of entry to being productive with the .NET Framework is still pretty high. The MVC style helpers Microsoft provides are a good step in the right direction, but I suspect it’s not enough to shield new developers from having to delve much deeper into the Framework to get even basic applications built. Razor and its helpers is trying to make .NET more accessible but the reality is that in order to do useful stuff that goes beyond the handful of simple helpers you still are going to have to write some C# or VB or other .NET code. If the target is a hobby/amateur/non-programmer the learning curve isn’t made any easier by WebMatrix it’s just been shifted a tad bit further along in your development endeavor when you run out of canned components that are supplied either by Microsoft or the community. The database helpers are interesting and actually I’ve heard a lot of discussion from various developers who’ve been resisting .NET for a really long time perking up at the prospect of easier data access in .NET than the ridiculous amount of code it takes to do even simple data access with raw ADO.NET. It seems sad that such a simple concept and implementation should trigger this sort of response (especially since it’s practically trivial to create helpers like these or pick them up from countless libraries available), but there it is. It also shows that there are plenty of developers out there who are more interested in ‘getting stuff done’ easily than necessarily following the latest and greatest practices which are overkill for many development scenarios. Sometimes it seems that all of .NET is focused on the big life changing issues of development, rather than the bread and butter scenarios that many developers are interested in to get their work accomplished. And that in the end may be WebMatrix’s main raison d'être: To bring some focus back at Microsoft that simpler and more high level solutions are actually needed to appeal to the non-high end developers as well as providing the necessary tools for the high end developers who want to follow the latest and greatest trends. The current version of WebMatrix hits many sweet spots, but it also feels like it has a long way to go before it really can be a tool that a beginning developer or an accomplished developer can feel comfortable with. Although there are some really good ideas in the environment (like the gallery for downloading apps and components) which would be a great addition for Visual Studio as well, the rest of the development environment just feels like crippleware with required functionality missing especially debugging and Intellisense, but also general editor support. It’s not clear whether these are because the product is still in an early alpha release or whether it’s simply designed that way to be a really limited development environment. While simple can be good, nobody wants to feel left out when it comes to necessary tool support and WebMatrix just has that left out feeling to it. If anything WebMatrix’s technology pieces (which are really independent of the WebMatrix product) are what are interesting to developers in general. The compact IIS implementation is a nice improvement for development scenarios and SQL Compact 4.0 seems to address a lot of concerns that people have had and have complained about for some time with previous SQL Compact implementations. By far the most interesting and useful technology though seems to be the Razor view engine for its light weight implementation and it’s decoupling from the ASP.NET/HTTP pipeline to provide a standalone scripting/view engine that is pluggable. The first winner of this is going to be ASP.NET MVC which can now have a cleaner view model that isn’t inconsistent due to the baggage of non-implemented WebForms features that don’t work in MVC. But I expect that Razor will end up in many other applications as a scripting and code generation engine eventually. Visual Studio integration for Razor is currently missing, but is promised for a later release. The ASP.NET MVC team has already mentioned that Razor will eventually become the default MVC view engine, which will guarantee continued growth and development of this tool along those lines. And the Razor engine and support tools actually inherit many of the features that MVC pioneered, so there’s some synergy flowing both ways between Razor and MVC. As an existing ASP.NET developer who’s already familiar with Visual Studio and ASP.NET development, the WebMatrix IDE doesn’t give you anything that you want. The tools provided are minimal and provide nothing that you can’t get in Visual Studio today, except the minimal Razor syntax highlighting, so there’s little need to take a step back. With Visual Studio integration coming later there’s little reason to look at WebMatrix for tooling. It’s good to see that Microsoft is giving some thought about the ease of use of .NET as a platform For so many years, we’ve been piling on more and more new features without trying to take a step back and see how complicated the development/configuration/deployment process has become. Sometimes it’s good to take a step - or several steps - back and take another look and realize just how far we’ve come. WebMatrix is one of those reminders and one that likely will result in some positive changes on the platform as a whole. © Rick Strahl, West Wind Technologies, 2005-2010Posted in ASP.NET   IIS7  

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  • Two more Entity Framework videos on Pluralsight

    Two new videos that I have created for Visual Studio 2010 have just been published to Pluralsight On-Demand. If you dont have a Pluralsight subscription (yet), these videos are available as part of PODs free guest pass along with lots of other great content. The new vids are Exploring the Classes Generated from an Entity Data Model and Consuming an Entity Data Model from a Separate .NET Project. Theyll be available on the MSDN Data Developer center as well (msdn.microsoft.com/data) in the very...Did you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.

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  • Stumbling Through: Making a case for the K2 Case Management Framework

    I have recently attended a three-day training session on K2s Case Management Framework (CMF), a free framework built on top of K2s blackpearl workflow product, and I have come away with several different impressions for some of the different aspects of the framework.  Before we get into the details, what is the Case Management Framework?  It is essentially a suite of tools that, when used together, solve many common workflow scenarios.  The tool has been developed over time by K2 consultants that have realized they tend to solve the same problems over and over for various clients, so they attempted to package all of those common solutions into one framework.  Most of these common problems involve workflow process that arent necessarily direct and would tend to be difficult to model.  Such solutions could be achieved in blackpearl alone, but the workflows would be complex and difficult to follow and maintain over time.  CMF attempts to simplify such scenarios not so much by black-boxing the workflow processes, but by providing different points of entry to the processes allowing them to be simpler, moving the complexity to a middle layer.  It is not a solution in and of itself, development is still required to tie the pieces together. CMF is under continuous development, both a plus and a minus in that bugs are fixed quickly and features added regularly, but it may be difficult to know which versions are the most stable.  CMF is not an officially supported K2 product, which means you will not get technical support but you will get access to the source code. The example given of a business process that would fit well into CMF is that of a file cabinet, where each folder in said file cabinet is a case that contains all of the data associated with one complaint/customer/incident/etc. and various users can access that case at any time and take one of a set of pre-determined actions on it.  When I was given that example, my first thought was that any workflow I have ever developed in the past could be made to fit this model there must be more than just this model to help decide if CMF is the right solution.  As the training went on, we learned that one of the key features of CMF is SharePoint integration as each case gets a SharePoint site created for it, and there are a number of excellent web parts that can be used to design a portal for users to get at all the information on their cases.  While CMF does not require SharePoint, without it you will be missing out on a huge portion of functionality that CMF offers.  My opinion is that without SharePoint integration, you may as well write your workflows and other components the old fashioned way. When I heard that each case gets its own SharePoint site created for it, warning bells immediately went off in my head as I felt that depending on the data load, a CMF enabled solution could quickly overwhelm SharePoint with thousands of sites so we have yet another deciding factor for CMF:  Just how many cases will your solution be creating?  While it is not necessary to use the site-per-case model, it is one of the more useful parts of the framework.  Without it, you are losing a big chunk of what CMF has to offer. When it comes to developing on top of the Case Management Framework, it becomes a matter of configuring what makes up a case, what can be done to a case, where each action on a case should take the user, and then typing up actions to case statuses.  This last step is one that I immediately warmed up to, as just about every workflow Ive designed in the past needed some sort of mapping table to set the status of a work item based on the action being taken definitely one of those common solutions that it is good to see rolled up into a re-useable entity (and it gets a nice configuration UI to boot!).  This concept is a little different than traditional workflow design, in that you dont have to think of an end-to-end process around passing a case along a path, rather, you must envision the case as central object with workflow threads branching off of it and doing their own thing with the case data.  Certainly there can be certain workflow threads that get rather complex, but the idea is that they RELATE to the case, they dont BECOME the case (though it is still possible with action->status mappings to prevent certain actions in certain cases, so it isnt always a wide-open free for all of actions on a case). I realize that this description of the Case Management Framework merely scratches the surface on what the product actually can do, and I dont think Ive conclusively defined for what sort of business scenario you can make a case for Case Management Framework.  What I do hope to have accomplished with this post is to raise awareness of CMF there is a (free!) product out there that could potentially simplify a tangled workflow process and give (for free!) a very useful set of SharePoint web parts and a nice set of (free!) reports.  The best way to see if it will truly fit your needs is to give it a try did I mention it is FREE?  Er, ok, so it is free, but only obtainable at this time for K2 partnersDid you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.

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  • HDWF [was OHDF]

    - by Glen McCallum
    Acronyms, acronyms ... same name (Oracle Healthcare Data Warehouse Foundation). Now it goes by HDWF. Don't ask me why. HDWF Version 2.0 was released quietly on 12 May. I'm told it is available on eDelivery. I've been spending more time working on HDWF this month. There's no question Oracle is moving at full-steam on this one. I've even spent a few nights this week working on India time with the team over there. We're busy moving Oracle's Operating Room Analytics application onto the new HDWF enterprise healthcare model. It's really been a great illustration of the comprehensiveness of the model. It was easily able accomodate all of the information required by ORA downstream.

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  • How to make custom shaped holes in terrain

    - by Guy Ben-Moshe
    So I'm trying to create a game where you fit certain shaped objects into the hole that fits them (similar to the young children's game with different shaped blocks) in Unity 3D. I've encountered a problem, how do I make the holes in the terrain? Or what type of object should I use for making holes in? So far I've tried to make a 3d model in unity by using other cubes and planes, it just doesn't feel right. I guess I need to create a model in another software and import to unity, I don't know any other software I can use. Tips would help.

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  • How do I draw a scene with 2 nested frames

    - by Guido Granobles
    I have been trying for long time to figure out this: I have loaded a model from a directx file (I am using opengl and Java) the model have a hierarchical system of nested reference frames (there are not bones). There are just 2 frames, one of them is called x3ds_Torso and it has a child frame called x3ds_Arm_01. Each one of them has a mesh. The thing is that I can't draw the arm connected to the body. Sometimes the body is in the center of the screen and the arm is at the top. Sometimes they are both in the center. I know that I have to multiply the matrix transformation of every frame by its parent frame starting from the top to the bottom and after that I have to multiply every vertex of every mesh by its final transformation matrix. So I have this: public void calculeFinalMatrixPosition(Bone boneParent, Bone bone) { System.out.println("-->" + bone.name); if (boneParent != null) { bone.matrixCombined = bone.matrixTransform.multiply(boneParent.matrixCombined); } else { bone.matrixCombined = bone.matrixTransform; } bone.matrixFinal = bone.matrixCombined; for (Bone childBone : bone.boneChilds) { calculeFinalMatrixPosition(bone, childBone); } } Then I have to multiply every vertex of the mesh: public void transformVertex(Bone bone) { for (Iterator<Mesh> iterator = meshes.iterator(); iterator.hasNext();) { Mesh mesh = iterator.next(); if (mesh.boneName.equals(bone.name)) { float[] vertex = new float[4]; double[] newVertex = new double[3]; if (mesh.skinnedVertexBuffer == null) { mesh.skinnedVertexBuffer = new FloatDataBuffer( mesh.numVertices, 3); } mesh.vertexBuffer.buffer.rewind(); while (mesh.vertexBuffer.buffer.hasRemaining()) { vertex[0] = mesh.vertexBuffer.buffer.get(); vertex[1] = mesh.vertexBuffer.buffer.get(); vertex[2] = mesh.vertexBuffer.buffer.get(); vertex[3] = 1; newVertex = bone.matrixFinal.transpose().multiply(vertex); mesh.skinnedVertexBuffer.buffer.put(((float) newVertex[0])); mesh.skinnedVertexBuffer.buffer.put(((float) newVertex[1])); mesh.skinnedVertexBuffer.buffer.put(((float) newVertex[2])); } mesh.vertexBuffer = new FloatDataBuffer( mesh.numVertices, 3); mesh.skinnedVertexBuffer.buffer.rewind(); mesh.vertexBuffer.buffer.put(mesh.skinnedVertexBuffer.buffer); } } for (Bone childBone : bone.boneChilds) { transformVertex(childBone); } } I know this is not the more efficient code but by now I just want to understand exactly how a hierarchical model is organized and how I can draw it on the screen. Thanks in advance for your help.

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  • Rotate sprite to face 3D camera

    - by omikun
    I am trying to rotate a sprite so it is always facing a 3D camera. shaders->setUniform("camera", gCamera.matrix()); glm::mat4 scale = glm::scale(glm::mat4(), glm::vec3(5e5, 5e5, 5e5)); glm::vec3 look = gCamera.position(); glm::vec3 right = glm::cross(gCamera.up(), look); glm::vec3 up = glm::cross(look, right); glm::mat4 newTransform = glm::lookAt(glm::vec3(0), gCamera.position(), up) * scale; shaders->setUniform("model", newTransform); In the vertex shader: gl_Position = camera * model * vec4(vert, 1); The object will track the camera if I move the camera up or down, but if I rotate the camera around it, it will rotate in the other direction so I end up seeing its front twice and its back twice as I rotate around it 360. What am I doing wrong?

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  • Builder Pattern: When to fail?

    - by skiwi
    When implementing the Builder Pattern, I often find myself confused with when to let building fail and I even manage to take different stands on the matter every few days. First some explanation: With failing early I mean that building an object should fail as soon as an invalid parameter is passed in. So inside the SomeObjectBuilder. With failing late I mean that building an object only can fail on the build() call that implicitely calls a constructor of the object to be built. Then some arguments: In favor of failing late: A builder class should be no more than a class that simply holds values. Moreover, it leads to less code duplication. In favor of failing early: A general approach in software programming is that you want to detect issues as early as possible and therefore the most logical place to check would be in the builder class' constructor, 'setters' and ultimately in the build method. What is the general concensus about this?

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  • What exactly is UV and UVW Mapping?

    - by Michael Stum
    Trying to understand some basic 3D concepts, at the moment I'm trying to figure out how textures actually work. I know that UV and UVW mapping are techniques that map 2D Textures to 3D Objects - Wikipedia told me as much. I googled for explanations but only found tutorials that assumed that I already know what it is. From my understanding, each 3D Model is made out of Points, and several points create a face? Does each point or face have a secondary coordinate that maps to a x/y position in the 2D Texture? Or how does unwrapping manipulate the model? Also, what does the W in UVW really do, what does it offer over UV? As I understand it, W maps to the Z coordinate, but in what situation would I have different textures for the same X/Y and different Z, wouldn't the Z part be invisible? Or am I completely misunderstanding this?

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  • Designing binary operations(AND, OR, NOT) in graphs DB's like neo4j

    - by Nicholas
    I'm trying to create a recipe website using a graph database, specifically neo4j using spring-data-neo4j, to try and see what can be done in Graph Databases. My model so far is: (Chef)-[HAS_INGREDIENT]->(Ingredient) (Chef)-[HAS_VALUE]->(Value) (Ingredient)-[HAS_INGREDIENT_VALUE]->(Value) (Recipe)-[REQUIRES_INGREDIENT]->(Ingredient) (Recipe)-[REQUIRES_VALUE]->(Value) I have this set up so I can do things like have the "chef" enter ingredients they have on hand, and suggest recipes, as well as suggest recipes that are close matches, but missing one ingredient. Some recipes can get complex, utilizing AND, OR, and NOT type logic, something like (Milk AND (Butter OR spread OR (vegetable oil OR olive oil))) and I'm wondering if it would be sane to model this in a graph using a tree type representation? An example of what I was thinking is to create three "node" types of AND, OR, and NOT and have each of them connect to the nodes value underneath. How else might this be represented in a Graph Database or is my example above a decent representation?

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  • Nagging As A Strategy For Better Linking: -z guidance

    - by user9154181
    The link-editor (ld) in Solaris 11 has a new feature that we call guidance that is intended to help you build better objects. The basic idea behind guidance is that if (and only if) you request it, the link-editor will issue messages suggesting better options and other changes you might make to your ld command to get better results. You can choose to take the advice, or you can disable specific types of guidance while acting on others. In some ways, this works like an experienced friend leaning over your shoulder and giving you advice — you're free to take it or leave it as you see fit, but you get nudged to do a better job than you might have otherwise. We use guidance to build the core Solaris OS, and it has proven to be useful, both in improving our objects, and in making sure that regressions don't creep back in later. In this article, I'm going to describe the evolution in thinking and design that led to the implementation of the -z guidance option, as well as give a brief description of how it works. The guidance feature issues non-fatal warnings. However, experience shows that once developers get used to ignoring warnings, it is inevitable that real problems will be lost in the noise and ignored or missed. This is why we have a zero tolerance policy against build noise in the core Solaris OS. In order to get maximum benefit from -z guidance while maintaining this policy, I added the -z fatal-warnings option at the same time. Much of the material presented here is adapted from the arc case: PSARC 2010/312 Link-editor guidance The History Of Unfortunate Link-Editor Defaults The Solaris link-editor is one of the oldest Unix commands. It stands to reason that this would be true — in order to write an operating system, you need the ability to compile and link code. The original link-editor (ld) had defaults that made sense at the time. As new features were needed, command line option switches were added to let the user use them, while maintaining backward compatibility for those who didn't. Backward compatibility is always a concern in system design, but is particularly important in the case of the tool chain (compilers, linker, and related tools), since it is a basic building block for the entire system. Over the years, applications have grown in size and complexity. Important concepts like dynamic linking that didn't exist in the original Unix system were invented. Object file formats changed. In the case of System V Release 4 Unix derivatives like Solaris, the ELF (Extensible Linking Format) was adopted. Since then, the ELF system has evolved to provide tools needed to manage today's larger and more complex environments. Features such as lazy loading, and direct bindings have been added. In an ideal world, many of these options would be defaults, with rarely used options that allow the user to turn them off. However, the reality is exactly the reverse: For backward compatibility, these features are all options that must be explicitly turned on by the user. This has led to a situation in which most applications do not take advantage of the many improvements that have been made in linking over the last 20 years. If their code seems to link and run without issue, what motivation does a developer have to read a complex manpage, absorb the information provided, choose the features that matter for their application, and apply them? Experience shows that only the most motivated and diligent programmers will make that effort. We know that most programs would be improved if we could just get you to use the various whizzy features that we provide, but the defaults conspire against us. We have long wanted to do something to make it easier for our users to use the linkers more effectively. There have been many conversations over the years regarding this issue, and how to address it. They always break down along the following lines: Change ld Defaults Since the world would be a better place the newer ld features were the defaults, why not change things to make it so? This idea is simple, elegant, and impossible. Doing so would break a large number of existing applications, including those of ISVs, big customers, and a plethora of existing open source packages. In each case, the owner of that code may choose to follow our lead and fix their code, or they may view it as an invitation to reconsider their commitment to our platform. Backward compatibility, and our installed base of working software, is one of our greatest assets, and not something to be lightly put at risk. Breaking backward compatibility at this level of the system is likely to do more harm than good. But, it sure is tempting. New Link-Editor One might create a new linker command, not called 'ld', leaving the old command as it is. The new one could use the same code as ld, but would offer only modern options, with the proper defaults for features such as direct binding. The resulting link-editor would be a pleasure to use. However, the approach is doomed to niche status. There is a vast pile of exiting code in the world built around the existing ld command, that reaches back to the 1970's. ld use is embedded in large and unknown numbers of makefiles, and is used by name by compilers that execute it. A Unix link-editor that is not named ld will not find a majority audience no matter how good it might be. Finally, a new linker command will eventually cease to be new, and will accumulate its own burden of backward compatibility issues. An Option To Make ld Do The Right Things Automatically This line of reasoning is best summarized by a CR filed in 2005, entitled 6239804 make it easier for ld(1) to do what's best The idea is to have a '-z best' option that unchains ld from its backward compatibility commitment, and allows it to turn on the "best" set of features, as determined by the authors of ld. The specific set of features enabled by -z best would be subject to change over time, as requirements change. This idea is more realistic than the other two, but was never implemented because it has some important issues that we could never answer to our satisfaction: The -z best proposal assumes that the user can turn it on, and trust it to select good options without the user needing to be aware of the options being applied. This is a fallacy. Features such as direct bindings require the user to do some analysis to ensure that the resulting program will still operate properly. A user who is willing to do the work to verify that what -z best does will be OK for their application is capable of turning on those features directly, and therefore gains little added benefit from -z best. The intent is that when a user opts into -z best, that they understand that z best is subject to sometimes incompatible evolution. Experience teaches us that this won't work. People will use this feature, the meaning of -z best will change, code that used to build will fail, and then there will be complaints and demands to retract the change. When (not if) this occurs, we will of course defend our actions, and point at the disclaimer. We'll win some of those debates, and lose others. Ultimately, we'll end up with -z best2 (-z better), or other compromises, and our goal of simplifying the world will have failed. The -z best idea rolls up a set of features that may or may not be related to each other into a unit that must be taken wholesale, or not at all. It could be that only a subset of what it does is compatible with a given application, in which case the user is expected to abandon -z best and instead set the options that apply to their application directly. In doing so, they lose one of the benefits of -z best, that if you use it, future versions of ld may choose a different set of options, and automatically improve the object through the act of rebuilding it. I drew two conclusions from the above history: For a link-editor, backward compatibility is vital. If a given command line linked your application 10 years ago, you have every reason to expect that it will link today, assuming that the libraries you're linking against are still available and compatible with their previous interfaces. For an application of any size or complexity, there is no substitute for the work involved in examining the code and determining which linker options apply and which do not. These options are largely orthogonal to each other, and it can be reasonable not to use any or all of them, depending on the situation, even in modern applications. It is a mistake to tie them together. The idea for -z guidance came from consideration of these points. By decoupling the advice from the act of taking the advice, we can retain the good aspects of -z best while avoiding its pitfalls: -z guidance gives advice, but the decision to take that advice remains with the user who must evaluate its merit and make a decision to take it or not. As such, we are free to change the specific guidance given in future releases of ld, without breaking existing applications. The only fallout from this will be some new warnings in the build output, which can be ignored or dealt with at the user's convenience. It does not couple the various features given into a single "take it or leave it" option, meaning that there will never be a need to offer "-zguidance2", or other such variants as things change over time. Guidance has the potential to be our final word on this subject. The user is given the flexibility to disable specific categories of guidance without losing the benefit of others, including those that might be added to future versions of the system. Although -z fatal-warnings stands on its own as a useful feature, it is of particular interest in combination with -z guidance. Used together, the guidance turns from advice to hard requirement: The user must either make the suggested change, or explicitly reject the advice by specifying a guidance exception token, in order to get a build. This is valuable in environments with high coding standards. ld Command Line Options The guidance effort resulted in new link-editor options for guidance and for turning warnings into fatal errors. Before I reproduce that text here, I'd like to highlight the strategic decisions embedded in the guidance feature: In order to get guidance, you have to opt in. We hope you will opt in, and believe you'll get better objects if you do, but our default mode of operation will continue as it always has, with full backward compatibility, and without judgement. Guidance suggestions always offers specific advice, and not vague generalizations. You can disable some guidance without turning off the entire feature. When you get guidance warnings, you can choose to take the advice, or you can specify a keyword to disable guidance for just that category. This allows you to get guidance for things that are useful to you, without being bothered about things that you've already considered and dismissed. As the world changes, we will add new guidance to steer you in the right direction. All such new guidance will come with a keyword that let's you turn it off. In order to facilitate building your code on different versions of Solaris, we quietly ignore any guidance keywords we don't recognize, assuming that they are intended for newer versions of the link-editor. If you want to see what guidance tokens ld does and does not recognize on your system, you can use the ld debugging feature as follows: % ld -Dargs -z guidance=foo,nodefs debug: debug: Solaris Linkers: 5.11-1.2275 debug: debug: arg[1] option=-D: option-argument: args debug: arg[2] option=-z: option-argument: guidance=foo,nodefs debug: warning: unrecognized -z guidance item: foo The -z fatal-warning option is straightforward, and generally useful in environments with strict coding standards. Note that the GNU ld already had this feature, and we accept their option names as synonyms: -z fatal-warnings | nofatal-warnings --fatal-warnings | --no-fatal-warnings The -z fatal-warnings and the --fatal-warnings option cause the link-editor to treat warnings as fatal errors. The -z nofatal-warnings and the --no-fatal-warnings option cause the link-editor to treat warnings as non-fatal. This is the default behavior. The -z guidance option is defined as follows: -z guidance[=item1,item2,...] Provide guidance messages to suggest ld options that can improve the quality of the resulting object, or which are otherwise considered to be beneficial. The specific guidance offered is subject to change over time as the system evolves. Obsolete guidance offered by older versions of ld may be dropped in new versions. Similarly, new guidance may be added to new versions of ld. Guidance therefore always represents current best practices. It is possible to enable guidance, while preventing specific guidance messages, by providing a list of item tokens, representing the class of guidance to be suppressed. In this way, unwanted advice can be suppressed without losing the benefit of other guidance. Unrecognized item tokens are quietly ignored by ld, allowing a given ld command line to be executed on a variety of older or newer versions of Solaris. The guidance offered by the current version of ld, and the item tokens used to disable these messages, are as follows. Specify Required Dependencies Dynamic executables and shared objects should explicitly define all of the dependencies they require. Guidance recommends the use of the -z defs option, should any symbol references remain unsatisfied when building dynamic objects. This guidance can be disabled with -z guidance=nodefs. Do Not Specify Non-Required Dependencies Dynamic executables and shared objects should not define any dependencies that do not satisfy the symbol references made by the dynamic object. Guidance recommends that unused dependencies be removed. This guidance can be disabled with -z guidance=nounused. Lazy Loading Dependencies should be identified for lazy loading. Guidance recommends the use of the -z lazyload option should any dependency be processed before either a -z lazyload or -z nolazyload option is encountered. This guidance can be disabled with -z guidance=nolazyload. Direct Bindings Dependencies should be referenced with direct bindings. Guidance recommends the use of the -B direct, or -z direct options should any dependency be processed before either of these options, or the -z nodirect option is encountered. This guidance can be disabled with -z guidance=nodirect. Pure Text Segment Dynamic objects should not contain relocations to non-writable, allocable sections. Guidance recommends compiling objects with Position Independent Code (PIC) should any relocations against the text segment remain, and neither the -z textwarn or -z textoff options are encountered. This guidance can be disabled with -z guidance=notext. Mapfile Syntax All mapfiles should use the version 2 mapfile syntax. Guidance recommends the use of the version 2 syntax should any mapfiles be encountered that use the version 1 syntax. This guidance can be disabled with -z guidance=nomapfile. Library Search Path Inappropriate dependencies that are encountered by ld are quietly ignored. For example, a 32-bit dependency that is encountered when generating a 64-bit object is ignored. These dependencies can result from incorrect search path settings, such as supplying an incorrect -L option. Although benign, this dependency processing is wasteful, and might hide a build problem that should be solved. Guidance recommends the removal of any inappropriate dependencies. This guidance can be disabled with -z guidance=nolibpath. In addition, -z guidance=noall can be used to entirely disable the guidance feature. See Chapter 7, Link-Editor Quick Reference, in the Linker and Libraries Guide for more information on guidance and advice for building better objects. Example The following example demonstrates how the guidance feature is intended to work. We will build a shared object that has a variety of shortcomings: Does not specify all it's dependencies Specifies dependencies it does not use Does not use direct bindings Uses a version 1 mapfile Contains relocations to the readonly allocable text (not PIC) This scenario is sadly very common — many shared objects have one or more of these issues. % cat hello.c #include <stdio.h> #include <unistd.h> void hello(void) { printf("hello user %d\n", getpid()); } % cat mapfile.v1 # This version 1 mapfile will trigger a guidance message % cc hello.c -o hello.so -G -M mapfile.v1 -lelf As you can see, the operation completes without error, resulting in a usable object. However, turning on guidance reveals a number of things that could be better: % cc hello.c -o hello.so -G -M mapfile.v1 -lelf -zguidance ld: guidance: version 2 mapfile syntax recommended: mapfile.v1 ld: guidance: -z lazyload option recommended before first dependency ld: guidance: -B direct or -z direct option recommended before first dependency Undefined first referenced symbol in file getpid hello.o (symbol belongs to implicit dependency /lib/libc.so.1) printf hello.o (symbol belongs to implicit dependency /lib/libc.so.1) ld: warning: symbol referencing errors ld: guidance: -z defs option recommended for shared objects ld: guidance: removal of unused dependency recommended: libelf.so.1 warning: Text relocation remains referenced against symbol offset in file .rodata1 (section) 0xa hello.o getpid 0x4 hello.o printf 0xf hello.o ld: guidance: position independent (PIC) code recommended for shared objects ld: guidance: see ld(1) -z guidance for more information Given the explicit advice in the above guidance messages, it is relatively easy to modify the example to do the right things: % cat mapfile.v2 # This version 2 mapfile will not trigger a guidance message $mapfile_version 2 % cc hello.c -o hello.so -Kpic -G -Bdirect -M mapfile.v2 -lc -zguidance There are situations in which the guidance does not fit the object being built. For instance, you want to build an object without direct bindings: % cc -Kpic hello.c -o hello.so -G -M mapfile.v2 -lc -zguidance ld: guidance: -B direct or -z direct option recommended before first dependency ld: guidance: see ld(1) -z guidance for more information It is easy to disable that specific guidance warning without losing the overall benefit from allowing the remainder of the guidance feature to operate: % cc -Kpic hello.c -o hello.so -G -M mapfile.v2 -lc -zguidance=nodirect Conclusions The linking guidelines enforced by the ld guidance feature correspond rather directly to our standards for building the core Solaris OS. I'm sure that comes as no surprise. It only makes sense that we would want to build our own product as well as we know how. Solaris is usually the first significant test for any new linker feature. We now enable guidance by default for all builds, and the effect has been very positive. Guidance helps us find suboptimal objects more quickly. Programmers get concrete advice for what to change instead of vague generalities. Even in the cases where we override the guidance, the makefile rules to do so serve as documentation of the fact. Deciding to use guidance is likely to cause some up front work for most code, as it forces you to consider using new features such as direct bindings. Such investigation is worthwhile, but does not come for free. However, the guidance suggestions offer a structured and straightforward way to tackle modernizing your objects, and once that work is done, for keeping them that way. The investment is often worth it, and will replay you in terms of better performance and fewer problems. I hope that you find guidance to be as useful as we have.

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  • Oracle Enterprise Manager 12c Delivers Advanced Self-Service Automation for Oracle Database 12c Multitenant

    - by Javier Puerta
    Broadens Support for Managing Full Lifecycle of New Pluggable Database as a Service Redwood Shores, Calif. – November 4, 2013 News Summary Database as a Service (DBaaS) offers organizations accelerated deployment, elastic capacity, greater consolidation efficiency, higher availability and lower overall operational cost and complexity. Oracle Database 12c provides an innovative multitenant architecture featuring pluggable databases that makes it easy to offer DBaaS and consolidate databases on clouds. To support customers’ move to this model, Oracle Enterprise Manager 12c adds new automation capabilities to enable quick provisioning of database clouds through self-service, saving administrators time and effort. These new capabilities can help customers adopt Oracle Database 12c faster and pave the way to a DBaaS delivery model. News Facts Oracle today announced a new release of Oracle Enterprise Manager 12c, which provides a turnkey, full lifecycle DBaaS management solution for Oracle Multitenant, an option for Oracle Database 12c Enterprise Edition. Read full press release here

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  • Oracle Enterprise Manager 12c Delivers Advanced Self-Service Automation for Oracle Database 12c Multitenant

    - by Javier Puerta
    Broadens Support for Managing Full Lifecycle of New Pluggable Database as a Service Redwood Shores, Calif. – November 4, 2013 News Summary Database as a Service (DBaaS) offers organizations accelerated deployment, elastic capacity, greater consolidation efficiency, higher availability and lower overall operational cost and complexity. Oracle Database 12c provides an innovative multitenant architecture featuring pluggable databases that makes it easy to offer DBaaS and consolidate databases on clouds. To support customers’ move to this model, Oracle Enterprise Manager 12c adds new automation capabilities to enable quick provisioning of database clouds through self-service, saving administrators time and effort. These new capabilities can help customers adopt Oracle Database 12c faster and pave the way to a DBaaS delivery model. News Facts Oracle today announced a new release of Oracle Enterprise Manager 12c, which provides a turnkey, full lifecycle DBaaS management solution for Oracle Multitenant, an option for Oracle Database 12c Enterprise Edition. Read full press release here

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  • Handling permissions in a MVP application

    - by Chathuranga
    In a windows forms payroll application employing MVP pattern (for a small scale client) I'm planing user permission handling as follows (permission based) as basically its implementation should be less complicated and straight forward. NOTE : System could be simultaneously used by few users (maximum 3) and the database is at the server side. This is my UserModel. Each user has a list of permissions given for them. class User { string UserID { get; set; } string Name { get; set; } string NIC {get;set;} string Designation { get; set; } string PassWord { get; set; } List <string> PermissionList = new List<string>(); bool status { get; set; } DateTime EnteredDate { get; set; } } When user login to the system it will keep the current user in memory. For example in BankAccountDetailEntering view I control the controller permission as follows. public partial class BankAccountDetailEntering : Form { bool AccountEditable {get; set;} private void BankAccountDetailEntering_Load(object sender, EventArgs e) { cmdEditAccount.enabled = false; OnLoadForm (sender, e); // Event fires... If (AccountEditable ) { cmdEditAccount.enabled=true; } } } In this purpose my all relevant presenters (like BankAccountDetailPresenter) should aware of UserModel as well in addition to the corresponding business Model it is presenting to the View. class BankAccountDetailPresenter { BankAccountDetailEntering _View; BankAccount _Model; User _UserModel; DataService _DataService; BankAccountDetailPresenter( BankAccountDetailEntering view, BankAccount model, User userModel, DataService dataService ) { _View=view; _Model = model; _UserModel = userModel; _DataService = dataService; WireUpEvents(); } private void WireUpEvents() { _View.OnLoadForm += new EventHandler(_View_OnLoadForm); } private void _View_OnLoadForm(Object sender, EventArgs e) { foreach(string s in _UserModel.PermissionList) { If( s =="CanEditAccount") { _View.AccountEditable =true; return; } } } public Show() { _View.ShowDialog(); } } So I'm handling the user permissions in the presenter iterating through the list. Should this be performed in the Presenter or View? Any other more promising ways to do this? Thanks.

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  • Benefits and features of different requirements-management systems and tools available?

    - by Gnark
    I am looking for a good comparision of different available professionial requirement managment tools. I am especially interested in the the features available within the different software solutions. Additionally to the "obvious" features I am looking for a proffesional Requirement Management System that supports for: multi-lingual customizable generation of documentation & history (graphs) search features (e.g. fulltext for comments), ordering, priorities version history bi-directional traceability of changes, artefacts, requirements, changes in requirements, etc. Any kind of integration of V-Model XT would be a really-nice-to-have-feature... Besides, I'd like to hear any personal motivated recommendations and/or experiences with different requirement management systems. Any input is highly appreciated. content consulted : similar question reqm tool with v-model nice, but too old paper (pdf) Tools Journal

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  • Benefits and features of different requirements-management systems and tools available?

    - by DevDevDave
    I am looking for a good comparision of different available professional requirement management tools. I am especially interested in the the features available within the different software solutions. Additionally to the "obvious" features I am looking for a proffesional Requirement Management System that supports for: multi-lingual customizable generation of documentation & history (graphs) search features (e.g. fulltext for comments), ordering, priorities version history bi-directional traceability of changes, artefacts, requirements, changes in requirements, etc. Any kind of integration of V-Model XT would be a really-nice-to-have-feature. Besides, I'd like to hear any personal motivated recommendations and/or experiences with different requirement management systems. Any input is highly appreciated. Content consulted: similar question reqm tool with v-model ToolsJournal.com nice, but too old paper (pdf)

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  • How should calculations be handled in a document database

    - by Morten
    Ok, so I have a program that basically logs errors into a nosql database. Right now there is just a single model for an error and its stored as a document in the nosql database. Basically I want to summarize across different errors and produce a summary of the "types" of errors that occured. Traditionally in a SQL database the this normalization would work with groupings, sums and averages but in a NoSQL database I assume I need to use mapreduce. My current model seems unfit for the task, how should I change the way I store "models" in order to make statistical analysis easy? Would a NoSQL database even be the right tool for this type of problem? I'm storing things in Google AppEngine's BigTable, so there are some limitations to think of as well.

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  • FigurePrint Brings Your Minecraft Creations to Life

    - by Jason Fitzpatrick
    If you love Minecraft so much you wish your finest creations could sit on your desk, FigurePrint is happy to oblige with a little 3D printing magic. Using their helper app you can export a section of your Minecraft world, big or small, upload it to their servers, and receive a full-color 3D printed model of it in the mail. The pricing is based on the size and complexity of model. Hit up the link to read more about their Minecraft printing services (as well as their Xbox Live avatar printing and World of War Craft printing). FigurePrint: Minecraft [via Wired] How To Delete, Move, or Rename Locked Files in Windows HTG Explains: Why Screen Savers Are No Longer Necessary 6 Ways Windows 8 Is More Secure Than Windows 7

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  • Clean way to use mutable implementation of Immutable interfaces for encapsulation

    - by dsollen
    My code is working on some compost relationship which creates a tree structure, class A has many children of type B, which has many children of type C etc. The lowest level class, call it bar, also points to a connected bar class. This effectively makes nearly every object in my domain inter-connected. Immutable objects would be problematic due to the expense of rebuilding almost all of my domain to make a single change to one class. I chose to go with an interface approach. Every object has an Immutable interface which only publishes the getter methods. I have controller objects which constructs the domain objects and thus has reference to the full objects, thus capable of calling the setter methods; but only ever publishes the immutable interface. Any change requested will go through the controller. So something like this: public interface ImmutableFoo{ public Bar getBar(); public Location getLocation(); } public class Foo implements ImmutableFoo{ private Bar bar; private Location location; @Override public Bar getBar(){ return Bar; } public void setBar(Bar bar){ this.bar=bar; } @Override public Location getLocation(){ return Location; } } public class Controller{ Private Map<Location, Foo> fooMap; public ImmutableFoo addBar(Bar bar){ Foo foo=fooMap.get(bar.getLocation()); if(foo!=null) foo.addBar(bar); return foo; } } I felt the basic approach seems sensible, however, when I speak to others they always seem to have trouble envisioning what I'm describing, which leaves me concerned that I may have a larger design issue then I'm aware of. Is it problematic to have domain objects so tightly coupled, or to use the quasi-mutable approach to modifying them? Assuming that the design approach itself isn't inherently flawed the particular discussion which left me wondering about my approach had to do with the presence of business logic in the domain objects. Currently I have my setter methods in the mutable objects do error checking and all other logic required to verify and make a change to the object. It was suggested that this should be pulled out into a service class, which applies all the business logic, to simplify my domain objects. I understand the advantage in mocking/testing and general separation of logic into two classes. However, with a service method/object It seems I loose some of the advantage of polymorphism, I can't override a base class to add in new error checking or business logic. It seems, if my polymorphic classes were complicated enough, I would end up with a service method that has to check a dozen flags to decide what error checking and business logic applies. So, for example, if I wanted to have a childFoo which also had a size field which should be compared to bar before adding par my current approach would look something like this. public class Foo implements ImmutableFoo{ public void addBar(Bar bar){ if(!getLocation().equals(bar.getLocation()) throw new LocationException(); this.bar=bar; } } public interface ImmutableChildFoo extends ImmutableFoo{ public int getSize(); } public ChildFoo extends Foo implements ImmutableChildFoo{ private int size; @Override public int getSize(){ return size; } @Override public void addBar(Bar bar){ if(getSize()<bar.getSize()){ throw new LocationException(); super.addBar(bar); } My colleague was suggesting instead having a service object that looks something like this (over simplified, the 'service' object would likely be more complex). public interface ImmutableFoo{ ///original interface, presumably used in other methods public Location getLocation(); public boolean isChildFoo(); } public interface ImmutableSizedFoo implements ImmutableFoo{ public int getSize(); } public class Foo implements ImmutableSizedFoo{ public Bar bar; @Override public void addBar(Bar bar){ this.bar=bar; } @Override public int getSize(){ //default size if no size is known return 0; } @Override public boolean isChildFoo return false; } } public ChildFoo extends Foo{ private int size; @Override public int getSize(){ return size; } @Override public boolean isChildFoo(); return true; } } public class Controller{ Private Map<Location, Foo> fooMap; public ImmutableSizedFoo addBar(Bar bar){ Foo foo=fooMap.get(bar.getLocation()); service.addBarToFoo(foo, bar); returned foo; } public class Service{ public static void addBarToFoo(Foo foo, Bar bar){ if(foo==null) return; if(!foo.getLocation().equals(bar.getLocation())) throw new LocationException(); if(foo.isChildFoo() && foo.getSize()<bar.getSize()) throw new LocationException(); foo.setBar(bar); } } } Is the recommended approach of using services and inversion of control inherently superior, or superior in certain cases, to overriding methods directly? If so is there a good way to go with the service approach while not loosing the power of polymorphism to override some of the behavior?

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  • How to price code reviews to encourage good behavior?

    - by Chris Clark
    I work for a company that has a hosted .net internet application with many clients. Those clients often want to write customizations for our application. We have APIs to hook into the app, but the customizations themselves are written in .net. This is a shared, secure hosting environment and we have to code review these customizations before we can deploy them in our datacenter to ensure that they don't degrade performance, crash our servers, or open any security vulnerabilities. We charge for these code reviews. The current pricing model is simply a function of the number of lines of code. I think this is a bad idea for a variety of reasons, but primarily because, if we are interested in verifying that the code works as expected, we should be incentivizing good, readable code, not compaction. I would like to propose a pricing model that incorporates some, or all of the following as inputs: Lines of code Cyclomatic complexity Avg function length # of functions Are there any other metrics I should incorporate, or other ideas for how we can reasonably create pricing for code reviews that encourages safe and understandable code?

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  • Building a database class in PHP

    - by Sprottenwels
    I wonder if I should write a database class for my application, and if so, how to accomplish it? Over there on SO, a guy mentioned it should be written as an abstract class. However, I can't understand why this would be a benefit. Do I understand correctly, that if I would write an abstract class, every other class that methods will need a database connection, could simply extend this abstract class and have it's own database object? If so, how is this different from a "normal" class where I could instantiate an database object? Another method would be to completely forget about my own class and to instantiate a mysqli object on demand. What do you recommend?

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  • Problem using glm::lookat

    - by omikun
    I am trying to rotate a sprite so it is always facing a 3D camera. Object GLfloat vertexData[] = { // X Y Z U V 0.0f, 0.8f, 0.0f, 0.5f, 1.0f, -0.8f,-0.8f, 0.0f, 0.0f, 0.0f, 0.8f,-0.8f, 0.0f, 1.0f, 0.0f, }; Per frame transform glm::mat4 newTransform = glm::lookAt(glm::vec3(0), gCamera.position(), gCamera.up()); shaders->setUniform("camera", gCamera.matrix()); shaders->setUniform("model", newTransform); In the vertex shader: gl_Position = camera * model * vec4(vert, 1); The object will track the camera if I move the camera up or down, but if I move the camera left/right (spin the camera around the object's y axis), it will rotate in the other direction so I end up seeing its front twice and its back twice as I rotate around it 360. If I use -gCamera.up() instead, it would track the camera side to side, but spin the opposite direction when I move the camera up/down. What am I doing wrong?

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  • Closing the gap between strategy and execution with Oracle Business Intelligence 11g

    - by manan.goel(at)oracle.com
    Wikipedia defines strategy as a plan of action designed to achieve a particular goal. An example of this is General Electric's acquisitions and divestiture strategy (plan) designed to propel GE to number 1 or 2 place (goal) in every business segment that it operated in. Execution on the other hand can be defined as the actions taken to getting things done. In GE's case execution will be steps followed for mergers/acquisitions or divestiture. Business press has written extensively about the importance of both strategy and execution in achieving desired business objectives. Perhaps the quote from Thomas Edison says it best - "vision without execution is hallucination". Conversely, it can be said that "execution without vision" is well may be "wishful thinking". Research overwhelmingly point towards the wide gap between strategy and execution. According to a published study, 49% of surveyed executives perceive a gap between their organizations' ability to develop and communicate sound strategies and their ability to implement those strategies. Further, of these respondents, 64% don't have full confidence that their companies will be able to close the gap. Having established the severity and importance of the problem let's talk about the reasons for the strategy-execution gap. The common reasons include: -        Lack of clearly defined goals -        Lack of consistent measure of success -        Lack of ownership -        Lack of alignment -        Lack of communication -        Lack of proper execution -        Lack of monitoring       There are multiple approaches to solving the problem including organizational development practices, technology enablement etc. In most cases a combination of approaches is required to achieve the desired result. For the purposes of this discussion, I'll focus on technology.  Imagine an integrated closed loop technology platform that automates the entire management cycle from defining strategy to assigning ownership to communicating goals to achieving alignment to collaboration to taking actions to monitoring progress and achieving mid course corrections. Besides, for best ROI and lowest TCO such a system should also have characteristics like:  Complete -        Full functionality -        Rich end user access Open -        Any data source -        Any business application -        Any technology stack  Integrated -        Common metadata -        Common security -        Common system management From a capabilities perspective the system should provide the following capabilities: Define -        Strategy -        Objectives -        Ownership -        KPI's Communicate -        Pervasive -        Collaborative -        Role based -        Secure Execute -        Integrated -        Intuitive -        Secure -        Ubiquitous Monitor -        Multiple styles and formats -        Exception based -        Push & Pull Having talked about the business problem and outlined the blueprint for a technology solution, let's talk about how Oracle Business Intelligence 11g can help. Oracle Business Intelligence is a comprehensive business intelligence solution for reporting, ad hoc query and analysis, OLAP, dashboards and scorecards. Oracle's best in class BI platform is based on an architecturally integrated technology foundation that provides a unified end user experience and features a Common Enterprise Information Model, with common security, query request generation and optimization, and system management. The BI platform is ·         Complete - meaning it delivers all modes and styles of BI including reporting, ad hoc query and analysis, OLAP, dashboards and scorecards with a rich end user experience that includes visualization, collaboration, alerts and notifications, search and mobile access. ·         Open - meaning the BI platform integrates with any data source, ETL tool, business application, application server, security infrastructure, portal technology as well as any ODBC compliant third party analytical tool. The suite accesses data from multiple heterogeneous sources--including popular relational and multidimensional data sources and major ERP and CRM applications from Oracle and SAP. ·         Integrated - meaning the BI platform is based on an architecturally integrated technology foundation built on an open, standards based service oriented architecture.  The platform features a common enterprise information model, common security model and a common configuration, deployment and systems management framework. To summarize, Oracle Business Intelligence is a comprehensive, integrated BI platform that lets you define strategy, identify objectives, assign ownership, define KPI's, collaborate, take action, monitor, report and do course corrections all form a single interface and a single system. The platform's integrated metadata model and task based design ensures that the entire workflow from defining strategy to execution to monitoring is completely integrated delivering end to end visibility, transparency and agility. Click here to learn more about Oracle BI 11g. 

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  • android: How to apply pinch zoom and pan to 2D GLSurfaceView

    - by mak_just4anything
    I want to apply pinch zoom and panning effect on GLSurfaceView. It is Image editor, so It would not be 3D object. I tried to implement using these following links: https://groups.google.com/forum/#!topic/android-developers/EVNRDNInVRU Want to apply pinch and zoom to GLSurfaceView(3d Object) http://www.learnopengles.com/android-lesson-one-getting-started/ These all are links for 3D object rendering. I can not use ImageView as I need to work out with OpenGL so, had to implement it on GLSurfaceView. Suggest me or any reference links are there for such implementation. **I need it for 2D only.

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