projection matrix - Page 85

CodePlex Daily Summary for Tuesday, October 09, 2012

CodePlex Daily Summary for Tuesday, October 09, 2012Popular ReleasesScript SQL Server Configuration: Release 3.0.9: Release 3.0.9 Rewrote trigger scripting. If encrypted triggers are encountered they are listed in a commented line. Scripts event notifications Added an option to script a single database (in addition to the instance) using the /scriptdb parameter. Script user-defined end points Script Service Broker objects Skip database mail on Express EditionMicrosoft Ajax Minifier: Microsoft Ajax Minifier 4.69: Fix for issue #18766: build task should not build the output if it's newer than all the input files. Fix for Issue #18764: build taks -res switch not working. update build task to concatenate input source and then minify, rather than minify and then concatenate. include resource string-replacement root name in the assumed globals list. Stop replacing new Date().getTime() with +new Date -- the latter is smaller, but turns out it executes up to 45% slower. add CSS support for single-...D3 Loot Tracker: 1.5.2: now recording server ip for each drop.WinRT XAML Toolkit: WinRT XAML Toolkit - 1.3.3: WinRT XAML Toolkit based on the Windows 8 RTM SDK. Download the latest source from the SOURCE CODE page. For compiled version use NuGet. You can add it to your project in Visual Studio by going to View/Other Windows/Package Manager Console and entering: PM> Install-Package winrtxamltoolkit Features Attachable Behaviors AwaitableUI extensions Controls Converters Debugging helpers Extension methods Imaging helpers IO helpers VisualTree helpers Samples Recent changes NOTE:...DevLib: 69721 binary dll: 69721 binary dllVidCoder: 1.4.4 Beta: Fixed inability to create new presets with "Save As".MCEBuddy 2.x: MCEBuddy 2.3.2: Changelog for 2.3.2 (32bit and 64bit) 1. Added support for generating XBMC XML NFO files for files in the conversion queue (store it along with the source video with source video name.nfo). Right click on the file in queue and select generate XML 2. UI bugifx, start and end trim box locations interchanged 3. Added support for removing commercials from non DVRMS/WTV files (MP4, AVI etc) 4. Now checking for Firewall port status before enabling (might help with some firewall problems) 5. User In...Sandcastle Help File Builder: SHFB v1.9.5.0 with Visual Studio Package: General InformationIMPORTANT: On some systems, the content of the ZIP file is blocked and the installer may fail to run. Before extracting it, right click on the ZIP file, select Properties, and click on the Unblock button if it is present in the lower right corner of the General tab in the properties dialog. This release supports the Sandcastle October 2012 Release (v2.7.1.0). It includes full support for generating, installing, and removing MS Help Viewer files. This new release suppor...Sofire Suite v1.6: XSqlModelGenerator.AddIn: 1、?? VS2010/2012 2、?? .NET FRAMEWORK 2.0 3、?? SOFIRE V1.6ClosedXML - The easy way to OpenXML: ClosedXML 0.68.0: ClosedXML now resolves formulas! Yes it finally happened. If you call cell.Value and it has a formula the library will try to evaluate the formula and give you the result. For example: var wb = new XLWorkbook(); var ws = wb.AddWorksheet("Sheet1"); ws.Cell("A1").SetValue(1).CellBelow().SetValue(1); ws.Cell("B1").SetValue(1).CellBelow().SetValue(1); ws.Cell("C1").FormulaA1 = "\"The total value is: \" & SUM(A1:B2)"; var...Json.NET: Json.NET 4.5 Release 10: New feature - Added Portable build to NuGet package New feature - Added GetValue and TryGetValue with StringComparison to JObject Change - Improved duplicate object reference id error message Fix - Fixed error when comparing empty JObjects Fix - Fixed SecAnnotate warnings Fix - Fixed error when comparing DateTime JValue with a DateTimeOffset JValue Fix - Fixed serializer sometimes not using DateParseHandling setting Fix - Fixed error in JsonWriter.WriteToken when writing a DateT...Readable Passphrase Generator: KeePass Plugin 0.7.2: Changes: Tested against KeePass 2.20.1 Tested under Ubuntu 12.10 (and KeePass 2.20) Added GenerateAsUtf8 method returning the encrypted passphrase as a UTF8 byte array.patterns & practices: Prism: Prism for .NET 4.5: This is a release does not include any functionality changes over Prism 4.1 Desktop. These assemblies target .NET 4.5. These assemblies also were compiled against updated dependencies: Unity 3.0 and Common Service Locator (Portable Class Library).Snoop, the WPF Spy Utility: Snoop 2.8.0: Snoop 2.8.0Announcing Snoop 2.8.0! It's been exactly six months since the last release, and this one has a bunch of goodies in it. In particular, there is now a PowerShell scripting tab, compliments of Bailey Ling. With this tab, the possibilities are limitless. It basically lets you automate/script the application that you are Snooping. Bailey has a couple blog posts (one and two) on his tab already, and I am sure more is to come. Please note that if you do not have PowerShell installed, y...Z3: Z3 4.1.2: Minor fixes. Now, z3 compiles with gcc 4.7.x.NET Micro Framework: .NET MF 4.3 (Beta): This is the 4.3 Beta version of the .NET Micro Framework. Feature List for v4.3 Support for Visual Studio 2012 (including the Windows Desktop Express version) All v4.2 QFEs features and bug fixes (PWM enhancements, lwIP and network driver reliability improvements, Analog Output, WinUSB and latest GCC support) Improved diagnostic information for deployment Decreased boot time Bug fixes Work Item 1736 - Create link for MFDeploy under start menu Work Item 1504 - Customizing lwIP o...NTCPMSG: V1.2.0.0: Allocate an identify cableid for each single connection cable. * Server can asend to specified cableid directly.Team Foundation Server Word Add-in: Version 1.0.12.0622: Welcome to the Visual Studio Team Foundation Server Word Add-in Supported Environments Microsoft Office Word 2007 and 2010 X86 (32-bit) Team Foundation Server 2010 Object Model TFS 2010, 2012 and TFS Service supported, using TFS OM / Explorer 2010. Quality-Bar Details Tool has been reviewed by Visual Studio ALM Rangers Tool has been through an independent technical and quality review All critical bugs have been resolved Known Issues / Bugs WI#43553 - The Acceptance criteria is not pu...UMD????? - PC?: UMDEditor?????V2.7: ??：http://jianyun.org/archives/948.html =============================================================================== UMD??? ???? =============================================================================== 2.7.0 (2012-10-3) ???????“UMD???.exe”??“UMDEditor.exe” ?????????；????????，??????。??????，????！ ??64????，??????????????bug ?????????????，???? ???????????????? ???????????????，??????????bug ------------------------------------------------------- ?? reg.bat ????????????。 ????，??????txt/u...Untangler: Untangler 1.0.0: Add a missing file from first releaseNew Projects3dBuzz: Denise's website for 3d projection mapping artists to develop a web community to show and discuss their work.Advanced DataGridView with Excel-like auto filter: Windows Forms DataGridView Control with Excel-Like auto-filter context menu Windows Forms DataGridView ??????? ? Excel-???????? ????-????????azure media services admin panel: Simple azure media services dashboard. Upload media assets, queue encoder tasks and stream your audio\video assets.BackupCleaner.Net: A C#.Net-based tool for automatically removing old backups selectively. It can be used when you already make daily backups on disk, and want to clean them up while still keeping some of the ones made weeks, months or years ago.Bible Lib: BibleLib is a .net compatible library containing information for books, chapters and verses in the Old Testament.CRM 4.0 to CRM 2011 Queues Upgrades: for more information and documentation, please refer to http://mayankp.wordpress.com/2012/05/25/crm-4-0-to-crm-2011-queues-upgrades/ CSV File Reader and Writer for .NET: C# classes for reading and writing CSV files. Support for multi-line fields, custom delimiter and quote characters, options for how empty lines are handled.DotNetNuke Boards: DNN Boards is a task management solution that allows each user to have their own task board or social group members can collaborate within a single board.FarmaciasCruzAzul: Sistema Cruz AzulFindValueInDatabase: This solution finds the value you input in the hole given database and tells you which columns of which tables have the value you are looking for.Fish Tank: Social networking site for Aquarium enthusiasts.GSBA Apps: GSBA App for Windows 8Heuristics for the Vehicle Routing Problem: This is the code for our class, IEMS 482.Icaro - UPN: Icaro UPN es la recopilación de todos los preyectos realizados en clases de los diferentes proyectos que Enseño, espero les Sirva.JSLogger - free logging library for JavaScript: JSLogger is a free JavaScript Library for log information during the duration of your client script. The target is very easy >>Find every javasvript error<<Just little strategy: Just little strategy writen in C# using XNA Game Studio Now under developmentLightweight Medata Reader: The Lightweight Metadata Reader (LMR) is a tooling friendly version of the CLR Reflection APIs that takes no dependency on the CLR Loader.My Solution: No description for it nowoden????: ???????????????＾＾ooaavee.net: TODOPath Splitter: Path Splitter uses Roslyn to convert a method into a set of methods each equivalent to a distinct execution path. Assume annotations are added for use with Pex.Planning Poker for Azure: Planning Poker application allows distributed teams to play planning poker just using web browser. It can be deployed to IIS or Azure cloud service.plasmatrim.net: A library for controlling the USB PlasmaTrim from a .net application.powersaver: A simple utility, which will turn off your monitor when you lock your work station.Project13251008: gterProject13261008: asdsaProject13271008: sdfPyfus Reload: Server-side framework for Dofus 1.29.1 gameRei do Biscuit: E-commerce do rei do biscuitSofire Suite v1.6: Sofire Suite v1.6Sofire XSql: Sofire XSqlSosa Analysis Module (SAM): Numerical Analysis and data visualization program for SOSA psychological experiment software.SyncProject: The summary is coming soon... Just be patient ! Tistory Syntax Highlighter: ???? SyntaxHighlighter ????TJBHJJ: this is a website for company!tricogol App: nonetuts: My first SVNWatchr Change Control Management: Change control management for development and administrative teams focused on lean or agile processes.WCF Simple multi chat: This is a simple Windows form application that it's like a 'chat room'. Multiple users can login and chat with others users. The chat's core is powered by WCFWindows Event Log Email Notification: This will read the windows event logs based on the supplied xpath filters and email the specified addresses if there are matches.

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Corsair Hackers Reboot

It wasn't easy for me to attend but it was absolutely worth to go. The Linux User Group of Mauritius (LUGM) organised another get-together for any open source enthusiast here on the island. Strangely named "Corsair Hackers Reboot" but it stands for a positive cause: "Corsair Hackers Reboot Event A collaborative activity involving LUGM, UoM Computer Club, Fortune Way Shopping Mall and several geeks from around the island, striving to put FOSS into homes & offices. The public is invited to discover and explore Free Software & Open Source." And it was a good opportunity for me and the kids to visit the east coast of Mauritius, too. Perfect timing It couldn't have been better... Why? Well, for two important reasons (in terms of IT): End of support for Microsoft Windows XP - 08.04.2014 Release of Ubuntu 14.04 Long Term Support - 17.04.2014 Quite funnily, those two IT dates weren't the initial reasons and only during the weeks of preparations we put those together. And therefore it was even more positive to promote the use of Linux and open source software in general to a broader audience. Getting there ... Thanks to the new motor way M3 and all the additional road work which has been completed recently it was very simple to get across the island in a very quick and relaxed manner. Compared to my trips in the early days of living in Mauritius (and riding on a scooter) it was very smooth and within less than an hour we hit Centrale de Flacq. Well, being in the city doesn't necessarily mean that one has arrived at the destination. But thanks to modern technology I had a quick look on Google Maps, and we finally managed to get a parking behind the huge bus terminal in Flacq. From there it was just a short walk to Fortune Way. The children were trying to count the number of buses... Well, lots and lots of buses - really impressive actually. What was presented? There were different areas set up. Right at the entrance one's attention was directly drawn towards the elevated hacker's stage. Similar to rock stars performing their gig there was bunch of computers, laptops and networking equipment in order to cater the right working conditions for coding/programming challenge(s) on the one hand and for the pen-testing or system hacking competition on the other hand. Personally, I was very impresses that actually Nitin took care of the pen-testing competition. He hardly started one year back with Linux in general, and Kali Linux specifically. Seeing his personal development from absolute newbie to a decent Linux system administrator within such a short period of time, is really impressive. His passion to open source software made him a living. Next, clock-wise seen, was the Kid's Corner with face-painting as the main attraction. Additionally, there were numerous paper print outs to colour. Plus a decent workstation with the educational suite GCompris. Of course, my little ones were into that. They already know GCompris since a while as they are allowed to use it on an IGEL thin client terminal here at home. To simplify my life, I set up GCompris as full-screen guest session on the server, and they can pass the login screen without any further obstacles. And because it's a thin client hooked up to a XDMCP remote session I don't have to worry about the hardware on their desk, too. The next section was the main attraction of the event: BYOD - Bring Your Own Device Well, compared to the usual context of BYOD the corsairs had a completely different intention. Here, you could bring your own laptop and a team of knowledgeable experts - read: geeks and so on - offered to fully convert your system on any Linux distribution of your choice. And even though I came later, I was told that the USB pen drives had been in permanent use. From being prepared via dd command over launching LiveCD session to finally installing a fresh Linux system on bare metal. Most interestingly, I did a similar job already a couple of months ago, while upgrading an existing Windows XP system to Xubuntu 13.10. So far, the female owner is very happy and enjoys her system almost every evening to go shopping online, checking mails, and reading latest news from the Anime world. Back to the Hackers event, Ish told me that they managed approximately 20 conversion during the day. Furthermore, Ajay and others gladly assisted some visitors with some tricky issues and by the end of the day you can call is a success. While I was around, there was a elderly male visitor that got a full-fledged system conversion to a Linux system running completely in French language. A little bit more to the centre it was Yasir's turn to demonstrate his Arduino hardware that he hooked up with an experimental electrical circuit board connected to an LCD matrix display. That's the real spirit of hacking, and he showed some minor adjustments on the fly while demo'ing the system. Also, very interesting there was a thermal sensor around. Personally, I think that platforms like the Arduino as well as the Raspberry Pi have a great potential at a very affordable price in order to bring a better understanding of electronics as well as computer programming to a broader audience. It would be great to see more of those experiments during future activities. And last but not least there were a small number of vendors. Amongst them was Emtel - once again as sponsor of the general internet connectivity - and another hardware supplier from Riche Terre shopping mall. They had a good collection of Android related gimmicks, like a autonomous web cam that can convert any TV with HDMI connector into an online video chat system given WiFi. It's actually kind of awesome to have a Skype or Google hangout video session on the big screen rather than on the laptop. Some pictures of the event LUGM: Great conversations on Linux, open source and free software during the Corsair Hackers Reboot LUGM: Educational workstation running GCompris suite attracted the youngest attendees of the day. Of course, face painting had to be done prior to hacking... LUGM: Nadim demoing some Linux specifics to interested visitors. Everyone was pretty busy during the whole day LUGM: The hacking competition, here pen-testing a wireless connection and access point between multiple machines LUGM: Well prepared workstations to be able to 'upgrade' visitors' machines to any Linux operating system Final thoughts Gratefully, during the preparations of the event I was invited to leave some comments or suggestions, and the team of the LUGM did a great job. The outdoor banner was a eye-catcher, the various flyers and posters for the event were clearly written and as far as I understood from the quick chats I had with Ish, Nadim, Nitin, Ajay, and of course others all were very happy about the event execution. Great job, LUGM! And I'm already looking forward to the next Corsair Hackers Reboot event ... Crossing fingers: Very soon and hopefully this year again :) Update: In the media The event had been announced in local media, too. L'Express: Salon informatique: Hacking Challenge à Flacq

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Free Document/Content Management System Using SharePoint 2010

- by KunaalKapoor

That’s right, it’s true. You can use the free version of SharePoint 2010 to meet your document and content management needs and even run your public facing website or an internal knowledge bank. SharePoint Foundation 2010 is free. It may not have all the features that you get in the enterprise license but it still has enough to cater to your needs to build a document management system and replace age old file shares or folders. I’ve built a dozen content management sites for internal and public use exploiting SharePoint. There are hundreds of web content management systems out there (see CMS Matrix). On one hand we have commercial platforms like SharePoint, SiteCore, and Ektron etc. which are the most frequently used and on the other hand there are free options like WordPress, Drupal, Joomla, and Plone etc. which are pretty common popular as well. But I would be very surprised if anyone was able to find a single CMS platform that is all things to all people. Infact not a lot of people consider SharePoint’s free version under the free CMS side but its high time organizations benefit from this. Through this blog post I wanted to present SharePoint Foundation as an option for running a FREE CMS platform. Even if you knew that there is a free version of SharePoint, what most people don’t realize is that SharePoint Foundation is a great option for running web sites of all kinds – not just team sites. It is a great option for many reasons, but in reality it is supported by Microsoft, and above all it is FREE (yay!), and it is extremely easy to get started. From a functionality perspective – it’s hard to beat SharePoint. Even the free version, SharePoint Foundation, offers simple data connectivity (through BCS), cross browser support, accessibility, support for Office Web Apps, blogs, wikis, templates, document support, health analyzer, support for presence, and MUCH more.I often get asked: “Can I use SharePoint 2010 as a document management system?” The answer really depends on · What are your specific requirements? · What systems you currently have in place for managing documents. · And of course how much money you have J Benefits? Not many large organizations have benefited from SharePoint yet. For some it has been an IT project to see what they can achieve with it, for others it has been used as a collaborative platform or in many cases an extended intranet. SharePoint 2010 has changed the game slightly as the improvements that Microsoft have made have been noted by organizations, and we are seeing a lot of companies starting to build specific business applications using SharePoint as the basis, and nearly every business process will require documents at some stage. If you require a document management system and have SharePoint in place then it can be a relatively straight forward decision to use SharePoint, as long as you have reviewed the considerations just discussed. The collaborative nature of SharePoint 2010 is also a massive advantage, as specific departmental or project sites can be created quickly and easily that allow workers to interact in a variety of different ways using one source of information. This also benefits an organization with regards to how they manage the knowledge that they have, as if all of their information is in one source then it is naturally easier to search and manage. Is SharePoint right for your organization? As just discussed, this can only be determined after defining your requirements and also planning a longer term strategy for how you will manage your documents and information. A key factor to look at is how the users would interact with the system and how much value would it get for your organization. The amount of data and documents that organizations are creating is increasing rapidly each year. Therefore the ability to archive this information, whilst keeping the ability to know what you have and where it is, is vital to any organizations management of their information life cycle. SharePoint is best used for the initial life of business documents where they need to be referenced and accessed after time. It is often beneficial to archive these to overcome for storage and performance issues. FREE CMS – SharePoint, Really? In order to show some of the completely of what comes with this free version of SharePoint 2010, I thought it would make sense to use Wikipedia (since every one trusts it as a credible source). Wikipedia shows that a web content management system typically has the following components: Document Management: - CMS software may provide a means of managing the life cycle of a document from initial creation time, through revisions, publication, archive, and document destruction. SharePoint is king when it comes to document management. Version history, exclusive check-out, security, publication, workflow, and so much more. Content Virtualization: - CMS software may provide a means of allowing each user to work within a virtual copy of the entire Web site, document set, and/or code base. This enables changes to multiple interdependent resources to be viewed and/or executed in-context prior to submission. Through the use of versioning, each content manager can preview, publish, and roll-back content of pages, wiki entries, blog posts, documents, or any other type of content stored in SharePoint. The idea of each user having an entire copy of the website virtualized is a bit odd to me – not sure why anyone would need that for anything but the simplest of websites. Automated Templates: - Create standard output templates that can be automatically applied to new and existing content, allowing the appearance of all content to be changed from one central place. Through the use of Master Pages and Themes, SharePoint provides the ability to change the entire look and feel of site. Of course, the older brother version of SharePoint – SharePoint Server 2010 – also introduces the concept of Page Layouts which allows page template level customization and even switching the layout of an individual page using different page templates. I think many organizations really think they want this but rarely end up using this bit of functionality. Easy Edits: - Once content is separated from the visual presentation of a site, it usually becomes much easier and quicker to edit and manipulate. Most WCMS software includes WYSIWYG editing tools allowing non-technical individuals to create and edit content. This is probably easier described with a screen cap of a vanilla SharePoint Foundation page in edit mode. Notice the page editing toolbar, the multiple layout options… It’s actually easier to use than Microsoft Word. Workflow management: - Workflow is the process of creating cycles of sequential and parallel tasks that must be accomplished in the CMS. For example, a content creator can submit a story, but it is not published until the copy editor cleans it up and the editor-in-chief approves it. Workflow, it’s in there. In fact, the same workflow engine is running under SharePoint Foundation that is running under the other versions of SharePoint. The primary difference is that with SharePoint Foundation – you need to configure the workflows yourself. Web Standards: - Active WCMS software usually receives regular updates that include new feature sets and keep the system up to current web standards. SharePoint is in the fourth major iteration under Microsoft with the 2010 release. In addition to the innovation that Microsoft continuously adds, you have the entire global ecosystem available. Scalable Expansion: - Available in most modern WCMSs is the ability to expand a single implementation (one installation on one server) across multiple domains. SharePoint Foundation can run multiple sites using multiple URLs on a single server install. Even more powerful, SharePoint Foundation is scalable and can be part of a multi-server farm to ensure that it will handle any amount of traffic that can be thrown at it. Delegation & Security: - Some CMS software allows for various user groups to have limited privileges over specific content on the website, spreading out the responsibility of content management. SharePoint Foundation provides very granular security capabilities. Read @ http://msdn.microsoft.com/en-us/library/ee537811.aspx Content Syndication: - CMS software often assists in content distribution by generating RSS and Atom data feeds to other systems. They may also e-mail users when updates are available as part of the workflow process. SharePoint Foundation nails it. With RSS syndication and email alerts available out of the box, content syndication is already in the platform. Multilingual Support: - Ability to display content in multiple languages. SharePoint Foundation 2010 supports more than 40 languages. Read More Read more @ http://msdn.microsoft.com/en-us/library/dd776256(v=office.12).aspxYou can download the free version from http://www.microsoft.com/en-us/download/details.aspx?id=5970

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GLSL: Strange light reflections [Solved]

- by Tom

According to this tutorial I'm trying to make a normal mapping using GLSL, but something is wrong and I can't find the solution. The output render is in this image: Image1 in this image is a plane with two triangles and each of it is different illuminated (that is bad). The plane has 6 vertices. In the upper left side of this plane are 2 identical vertices (same in the lower right). Here are some vectors same for each vertice: normal vector = 0, 1, 0 (red lines on image) tangent vector = 0, 0,-1 (green lines on image) bitangent vector = -1, 0, 0 (blue lines on image) here I have one question: The two identical vertices does need to have the same tangent and bitangent? I have tried to make other values to the tangents but the effect was still similar. Here are my shaders Vertex shader: #version 130 // Input vertex data, different for all executions of this shader. in vec3 vertexPosition_modelspace; in vec2 vertexUV; in vec3 vertexNormal_modelspace; in vec3 vertexTangent_modelspace; in vec3 vertexBitangent_modelspace; // Output data ; will be interpolated for each fragment. out vec2 UV; out vec3 Position_worldspace; out vec3 EyeDirection_cameraspace; out vec3 LightDirection_cameraspace; out vec3 LightDirection_tangentspace; out vec3 EyeDirection_tangentspace; // Values that stay constant for the whole mesh. uniform mat4 MVP; uniform mat4 V; uniform mat4 M; uniform mat3 MV3x3; uniform vec3 LightPosition_worldspace; void main(){ // Output position of the vertex, in clip space : MVP * position gl_Position = MVP * vec4(vertexPosition_modelspace,1); // Position of the vertex, in worldspace : M * position Position_worldspace = (M * vec4(vertexPosition_modelspace,1)).xyz; // Vector that goes from the vertex to the camera, in camera space. // In camera space, the camera is at the origin (0,0,0). vec3 vertexPosition_cameraspace = ( V * M * vec4(vertexPosition_modelspace,1)).xyz; EyeDirection_cameraspace = vec3(0,0,0) - vertexPosition_cameraspace; // Vector that goes from the vertex to the light, in camera space. M is ommited because it's identity. vec3 LightPosition_cameraspace = ( V * vec4(LightPosition_worldspace,1)).xyz; LightDirection_cameraspace = LightPosition_cameraspace + EyeDirection_cameraspace; // UV of the vertex. No special space for this one. UV = vertexUV; // model to camera = ModelView vec3 vertexTangent_cameraspace = MV3x3 * vertexTangent_modelspace; vec3 vertexBitangent_cameraspace = MV3x3 * vertexBitangent_modelspace; vec3 vertexNormal_cameraspace = MV3x3 * vertexNormal_modelspace; mat3 TBN = transpose(mat3( vertexTangent_cameraspace, vertexBitangent_cameraspace, vertexNormal_cameraspace )); // You can use dot products instead of building this matrix and transposing it. See References for details. LightDirection_tangentspace = TBN * LightDirection_cameraspace; EyeDirection_tangentspace = TBN * EyeDirection_cameraspace; } Fragment shader: #version 130 // Interpolated values from the vertex shaders in vec2 UV; in vec3 Position_worldspace; in vec3 EyeDirection_cameraspace; in vec3 LightDirection_cameraspace; in vec3 LightDirection_tangentspace; in vec3 EyeDirection_tangentspace; // Ouput data out vec3 color; // Values that stay constant for the whole mesh. uniform sampler2D DiffuseTextureSampler; uniform sampler2D NormalTextureSampler; uniform sampler2D SpecularTextureSampler; uniform mat4 V; uniform mat4 M; uniform mat3 MV3x3; uniform vec3 LightPosition_worldspace; void main(){ // Light emission properties // You probably want to put them as uniforms vec3 LightColor = vec3(1,1,1); float LightPower = 40.0; // Material properties vec3 MaterialDiffuseColor = texture2D( DiffuseTextureSampler, vec2(UV.x,-UV.y) ).rgb; vec3 MaterialAmbientColor = vec3(0.1,0.1,0.1) * MaterialDiffuseColor; //vec3 MaterialSpecularColor = texture2D( SpecularTextureSampler, UV ).rgb * 0.3; vec3 MaterialSpecularColor = vec3(0.5,0.5,0.5); // Local normal, in tangent space. V tex coordinate is inverted because normal map is in TGA (not in DDS) for better quality vec3 TextureNormal_tangentspace = normalize(texture2D( NormalTextureSampler, vec2(UV.x,-UV.y) ).rgb*2.0 - 1.0); // Distance to the light float distance = length( LightPosition_worldspace - Position_worldspace ); // Normal of the computed fragment, in camera space vec3 n = TextureNormal_tangentspace; // Direction of the light (from the fragment to the light) vec3 l = normalize(LightDirection_tangentspace); // Cosine of the angle between the normal and the light direction, // clamped above 0 // - light is at the vertical of the triangle -> 1 // - light is perpendicular to the triangle -> 0 // - light is behind the triangle -> 0 float cosTheta = clamp( dot( n,l ), 0,1 ); // Eye vector (towards the camera) vec3 E = normalize(EyeDirection_tangentspace); // Direction in which the triangle reflects the light vec3 R = reflect(-l,n); // Cosine of the angle between the Eye vector and the Reflect vector, // clamped to 0 // - Looking into the reflection -> 1 // - Looking elsewhere -> < 1 float cosAlpha = clamp( dot( E,R ), 0,1 ); color = // Ambient : simulates indirect lighting MaterialAmbientColor + // Diffuse : "color" of the object MaterialDiffuseColor * LightColor * LightPower * cosTheta / (distance*distance) + // Specular : reflective highlight, like a mirror MaterialSpecularColor * LightColor * LightPower * pow(cosAlpha,5) / (distance*distance); //color.xyz = E; //color.xyz = LightDirection_tangentspace; //color.xyz = EyeDirection_tangentspace; } I have replaced the original color value by EyeDirection_tangentspace vector and then I got other strange effect but I can not link the image (not eunogh reputation) Is it possible that with this shaders is something wrong, or maybe in other place in my code e.g with my matrices?

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Per-pixel displacement mapping GLSL

- by Chris

Im trying to implement a per-pixel displacement shader in GLSL. I read through several papers and "tutorials" I found and ended up with trying to implement the approach NVIDIA used in their Cascade Demo (http://www.slideshare.net/icastano/cascades-demo-secrets) starting at Slide 82. At the moment I am completly stuck with following problem: When I am far away the displacement seems to work. But as more I move closer to my surface, the texture gets bent in x-axis and somehow it looks like there is a little bent in general in one direction. EDIT: I added a video: click I added some screen to illustrate the problem: Well I tried lots of things already and I am starting to get a bit frustrated as my ideas run out. I added my full VS and FS code: VS: #version 400 layout(location = 0) in vec3 IN_VS_Position; layout(location = 1) in vec3 IN_VS_Normal; layout(location = 2) in vec2 IN_VS_Texcoord; layout(location = 3) in vec3 IN_VS_Tangent; layout(location = 4) in vec3 IN_VS_BiTangent; uniform vec3 uLightPos; uniform vec3 uCameraDirection; uniform mat4 uViewProjection; uniform mat4 uModel; uniform mat4 uView; uniform mat3 uNormalMatrix; out vec2 IN_FS_Texcoord; out vec3 IN_FS_CameraDir_Tangent; out vec3 IN_FS_LightDir_Tangent; void main( void ) { IN_FS_Texcoord = IN_VS_Texcoord; vec4 posObject = uModel * vec4(IN_VS_Position, 1.0); vec3 normalObject = (uModel * vec4(IN_VS_Normal, 0.0)).xyz; vec3 tangentObject = (uModel * vec4(IN_VS_Tangent, 0.0)).xyz; //vec3 binormalObject = (uModel * vec4(IN_VS_BiTangent, 0.0)).xyz; vec3 binormalObject = normalize(cross(tangentObject, normalObject)); // uCameraDirection is the camera position, just bad named vec3 fvViewDirection = normalize( uCameraDirection - posObject.xyz); vec3 fvLightDirection = normalize( uLightPos.xyz - posObject.xyz ); IN_FS_CameraDir_Tangent.x = dot( tangentObject, fvViewDirection ); IN_FS_CameraDir_Tangent.y = dot( binormalObject, fvViewDirection ); IN_FS_CameraDir_Tangent.z = dot( normalObject, fvViewDirection ); IN_FS_LightDir_Tangent.x = dot( tangentObject, fvLightDirection ); IN_FS_LightDir_Tangent.y = dot( binormalObject, fvLightDirection ); IN_FS_LightDir_Tangent.z = dot( normalObject, fvLightDirection ); gl_Position = (uViewProjection*uModel) * vec4(IN_VS_Position, 1.0); } The VS just builds the TBN matrix, from incoming normal, tangent and binormal in world space. Calculates the light and eye direction in worldspace. And finally transforms the light and eye direction into tangent space. FS: #version 400 // uniforms uniform Light { vec4 fvDiffuse; vec4 fvAmbient; vec4 fvSpecular; }; uniform Material { vec4 diffuse; vec4 ambient; vec4 specular; vec4 emissive; float fSpecularPower; float shininessStrength; }; uniform sampler2D colorSampler; uniform sampler2D normalMapSampler; uniform sampler2D heightMapSampler; in vec2 IN_FS_Texcoord; in vec3 IN_FS_CameraDir_Tangent; in vec3 IN_FS_LightDir_Tangent; out vec4 color; vec2 TraceRay(in float height, in vec2 coords, in vec3 dir, in float mipmap){ vec2 NewCoords = coords; vec2 dUV = - dir.xy * height * 0.08; float SearchHeight = 1.0; float prev_hits = 0.0; float hit_h = 0.0; for(int i=0;i<10;i++){ SearchHeight -= 0.1; NewCoords += dUV; float CurrentHeight = textureLod(heightMapSampler,NewCoords.xy, mipmap).r; float first_hit = clamp((CurrentHeight - SearchHeight - prev_hits) * 499999.0,0.0,1.0); hit_h += first_hit * SearchHeight; prev_hits += first_hit; } NewCoords = coords + dUV * (1.0-hit_h) * 10.0f - dUV; vec2 Temp = NewCoords; SearchHeight = hit_h+0.1; float Start = SearchHeight; dUV *= 0.2; prev_hits = 0.0; hit_h = 0.0; for(int i=0;i<5;i++){ SearchHeight -= 0.02; NewCoords += dUV; float CurrentHeight = textureLod(heightMapSampler,NewCoords.xy, mipmap).r; float first_hit = clamp((CurrentHeight - SearchHeight - prev_hits) * 499999.0,0.0,1.0); hit_h += first_hit * SearchHeight; prev_hits += first_hit; } NewCoords = Temp + dUV * (Start - hit_h) * 50.0f; return NewCoords; } void main( void ) { vec3 fvLightDirection = normalize( IN_FS_LightDir_Tangent ); vec3 fvViewDirection = normalize( IN_FS_CameraDir_Tangent ); float mipmap = 0; vec2 NewCoord = TraceRay(0.1,IN_FS_Texcoord,fvViewDirection,mipmap); //vec2 ddx = dFdx(NewCoord); //vec2 ddy = dFdy(NewCoord); vec3 BumpMapNormal = textureLod(normalMapSampler, NewCoord.xy, mipmap).xyz; BumpMapNormal = normalize(2.0 * BumpMapNormal - vec3(1.0, 1.0, 1.0)); vec3 fvNormal = BumpMapNormal; float fNDotL = dot( fvNormal, fvLightDirection ); vec3 fvReflection = normalize( ( ( 2.0 * fvNormal ) * fNDotL ) - fvLightDirection ); float fRDotV = max( 0.0, dot( fvReflection, fvViewDirection ) ); vec4 fvBaseColor = textureLod( colorSampler, NewCoord.xy,mipmap); vec4 fvTotalAmbient = fvAmbient * fvBaseColor; vec4 fvTotalDiffuse = fvDiffuse * fNDotL * fvBaseColor; vec4 fvTotalSpecular = fvSpecular * ( pow( fRDotV, fSpecularPower ) ); color = ( fvTotalAmbient + (fvTotalDiffuse + fvTotalSpecular) ); } The FS implements the displacement technique in TraceRay method, while always using mipmap level 0. Most of the code is from NVIDIA sample and another paper I found on the web, so I guess there cannot be much wrong in here. At the end it uses the modified UV coords for getting the displaced normal from the normal map and the color from the color map. I looking forward for some ideas. Thanks in advance! Edit: Here is the code loading the heightmap: glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, mWidth, mHeight, 0, GL_RGBA, GL_UNSIGNED_BYTE, mImageData); glGenerateMipmap(GL_TEXTURE_2D); //glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR_MIPMAP_LINEAR); //glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR); //glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT); //glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT); Maybe something wrong in here?

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CodePlex Daily Summary for Monday, September 03, 2012

CodePlex Daily Summary for Monday, September 03, 2012Popular ReleasesMetodología General Ajustada - MGA: 03.01.03: Cambios Aury: Ajuste del margen del reporte. Visualización de la columna de Supuestos en la parte del módulo de Decisión. Cambios John: Integración de código con cambios enviados por Aury Niño. Generación de instaladores. Soporte técnico por correo electrónico y telefónico.Iveely Search Engine: Iveely Search Engine （0.2.0）: ????ISE?0.1.0??，?????，ISE?0.2.0?????????，???????，????????20???follow?ISE，????，??ISE??????????，??????????，?????????，?????????0.2.0??????，??????????。 Iveely Search Engine ?0.2.0?????????“??????????”，??????，?????????，???????，???????????????????，????、????????????。???0.1.0????????????： 1. ??“????” ??。??????????，?????????，???????????????????。??：????????，????????????，??????????????????。??????。 2. ??“????”??。?0.1.0??????，???????，???????????????，?????????????，????????，?0.2.0?，???????...Thisismyusername's codeplex page.: HTML5 Mulititouch Fruit Ninja Proof of Concept: This is an example of how you could create a game such as Fruit Ninja using HTML5's multitouch capabilities. Sorry this example doesn't have great graphics. If I had my own webpage, I could store some graphics and upload the game there and it might look halfway decent, but since I'm only using a Codeplex page and most mobile devices can't open .zip files, the fruits are just circles. I hope you enjoy reading the source code anyway.GmailDefaultMaker: GmailDefaultMaker 3.0.0.2: Add QQ Mail BugfixSmart Data Access layer: Smart Data access Layer Ver 3: In this version support executing inline query is added. Check Documentation section for detail.TSQL Code Smells Finder: POC 1.01: Proof of concept 1.01 TSQLDomTest.ps1 and Errors.Txt are requiredConfuser: Confuser build 76542: This is a build of changeset 76542.Reactive State Machine: ReactiveStateMachine-beta: TouchStateMachine now supports Microsoft Surface 2.0 SDK. The TouchStateMachine is an extension to the Reactive State Machine. Reactive State Machine uses NuGet for dependency managementSharePoint Column & View Permission: SharePoint Column and View Permission v1.2: Version 1.2 of this project. If you will find any bugs please let me know at enti@zoznam.sk or post your findings in Issue TrackerMihmojsos OS: Mihmojsos OS 3 (Smart Rabbit): !Mihmojsos OS 3 Smart Rabbit Mihmojsos Smart Rabbit is now availableDotNetNuke Translator: 01.00.00 Beta: First release of the project.YNA: YNA 0.2 alpha: Wath's new since 0.1 alpha ? A lot of changes but there are the most interresting : StateManager is now better and faster Mouse events for all YnObjects (Sprites, Images, texts) A really big improvement for YnGroup Gamepad support And the news : Tiled Map support (need refactoring) Isometric tiled map support (need refactoring) Transition effect like "FadeIn" and "FadeOut" (YnTransition) Timers (YnTimer) Path management (YnPath, need more refactoring) Downloads All downloads...Audio Pitch & Shift: Audio Pitch And Shift 5.1.0.2: fixed several issues with streaming modeUrlPager: UrlPager 1.2: Fixed bug in which url parameters will lost after paging; ????????url???bug；Sofire Suite: Sofire v1.5.0.0: Sofire v1.5.0.0 ?? ???????? ?????： 1、?? 2、????EntLib.com????????: EntLib.com???????? v3.0: EntLib eCommerce Solution ???Microsoft .Net Framework?????????????????????。Coevery - Free CRM: Coevery 1.0.0.24: Add a sample database, and installation instructions.Math.NET Numerics: Math.NET Numerics v2.2.1: Major linear algebra rework since v2.1, now available on Codeplex as well (previous versions were only available via NuGet). Since v2.2.0: Student-T density more robust for very large degrees of freedom Sparse Kronecker product much more efficient (now leverages sparsity) Direct access to raw matrix storage implementations for advanced extensibility Now also separate package for signed core library with a strong name (we dropped strong names in v2.2.0) Also available as NuGet packages...Microsoft SQL Server Product Samples: Database: AdventureWorks Databases – 2012, 2008R2 and 2008: About this release This release consolidates AdventureWorks databases for SQL Server 2012, 2008R2 and 2008 versions to one page. Each zip file contains an mdf database file and ldf log file. This should make it easier to find and download AdventureWorks databases since all OLTP versions are on one page. There are no database schema changes. For each release of the product, there is a light-weight and full version of the AdventureWorks sample database. The light-weight version is denoted by ...Christoc's DotNetNuke Module Development Template: DotNetNuke Project Templates V1.1 for VS2012: This release is specifically for Visual Studio 2012 Support, distributed through the Visual Studio Extensions gallery at http://visualstudiogallery.msdn.microsoft.com/ After you build in Release mode the installable packages (source/install) can be found in the INSTALL folder now, within your module's folder, not the packages folder anymore Check out the blog post for all of the details about this release. http://www.dotnetnuke.com/Resources/Blogs/EntryId/3471/New-Visual-Studio-2012-Projec...New ProjectsBPVote4PPT: BPVote For PowerPointCosmo OS: La semplicità in un OSFinancial Analytic Tools: C#.Net Financial Analytic ToolsGeminiMVC: An Open Source CMS written in ASP.net MVC 4 with speed, extensibility, and ease-of-us in mind.JQuery SharePoint Autocomplete People Picker: This JQUery bundle provides an autocomplete people picker based on SharePoint profiles. It can be hosted on the SharePoint itself or on remote applications.Kerbal Space Program PartModule Library: This project is designed to add various functionalities to custom parts for the space program simulation game Kerbal Space Program.KeyboardRemapper: This tool to remaps keys in the keyboard. If you have more than one keyboard or an additional keypad, you can remap the keys of the each keyboard independentlyKHStudent: ??????Localized DataAnnotations with T4 templates: Simplified DataAnnotations localization using T4 templates.MfcLightToolkit: Supports development for small and simple MFC application. Provides asynchronous programming model like .NET, file download, easy control resizing, and so on.Müslüm ÖZTÜRK Code Lib: Test amaçli olusturulan projemdirPolska: Testproject in how a polish grammerprogram can look like.QueueLessApp: Here is the codeRusIS.CMS: aaaSGPS: Projeto de controle de produtos e serviçosStemmersNet: Stemmers pack for .Net FrameworkTrabajo Final de Ingenieria - Javier Vallejos: Tesis Final de la carrera de Ingenieria - Universidad Abierta Interamericana.TSQL Code Smells Finder: TSQL 'smells' findersXNA and Data Driven Design: This project includes links for XNA and Data Driven DesignXNA and System Testing: This project includes code for XNA and System TestingYUGI-AR Project: an open source project for yugioh based augmented reality???????? ? ?????????????: ???? ??????? ??????? ?????????????? ??????????? ?????????? ??? ? ????? ?????? ? ? ??? ??? ????? ? ??? ?????????? ????????????.

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GLSL: Strange light reflections

- by Tom

According to this tutorial I'm trying to make a normal mapping using GLSL, but something is wrong and I can't find the solution. The output render is in this image: Image1 in this image is a plane with two triangles and each of it is different illuminated (that is bad). The plane has 6 vertices. In the upper left side of this plane are 2 identical vertices (same in the lower right). Here are some vectors same for each vertice: normal vector = 0, 1, 0 (red lines on image) tangent vector = 0, 0,-1 (green lines on image) bitangent vector = -1, 0, 0 (blue lines on image) here I have one question: The two identical vertices does need to have the same tangent and bitangent? I have tried to make other values to the tangents but the effect was still similar. Here are my shaders Vertex shader: #version 130 // Input vertex data, different for all executions of this shader. in vec3 vertexPosition_modelspace; in vec2 vertexUV; in vec3 vertexNormal_modelspace; in vec3 vertexTangent_modelspace; in vec3 vertexBitangent_modelspace; // Output data ; will be interpolated for each fragment. out vec2 UV; out vec3 Position_worldspace; out vec3 EyeDirection_cameraspace; out vec3 LightDirection_cameraspace; out vec3 LightDirection_tangentspace; out vec3 EyeDirection_tangentspace; // Values that stay constant for the whole mesh. uniform mat4 MVP; uniform mat4 V; uniform mat4 M; uniform mat3 MV3x3; uniform vec3 LightPosition_worldspace; void main(){ // Output position of the vertex, in clip space : MVP * position gl_Position = MVP * vec4(vertexPosition_modelspace,1); // Position of the vertex, in worldspace : M * position Position_worldspace = (M * vec4(vertexPosition_modelspace,1)).xyz; // Vector that goes from the vertex to the camera, in camera space. // In camera space, the camera is at the origin (0,0,0). vec3 vertexPosition_cameraspace = ( V * M * vec4(vertexPosition_modelspace,1)).xyz; EyeDirection_cameraspace = vec3(0,0,0) - vertexPosition_cameraspace; // Vector that goes from the vertex to the light, in camera space. M is ommited because it's identity. vec3 LightPosition_cameraspace = ( V * vec4(LightPosition_worldspace,1)).xyz; LightDirection_cameraspace = LightPosition_cameraspace + EyeDirection_cameraspace; // UV of the vertex. No special space for this one. UV = vertexUV; // model to camera = ModelView vec3 vertexTangent_cameraspace = MV3x3 * vertexTangent_modelspace; vec3 vertexBitangent_cameraspace = MV3x3 * vertexBitangent_modelspace; vec3 vertexNormal_cameraspace = MV3x3 * vertexNormal_modelspace; mat3 TBN = transpose(mat3( vertexTangent_cameraspace, vertexBitangent_cameraspace, vertexNormal_cameraspace )); // You can use dot products instead of building this matrix and transposing it. See References for details. LightDirection_tangentspace = TBN * LightDirection_cameraspace; EyeDirection_tangentspace = TBN * EyeDirection_cameraspace; } Fragment shader: #version 130 // Interpolated values from the vertex shaders in vec2 UV; in vec3 Position_worldspace; in vec3 EyeDirection_cameraspace; in vec3 LightDirection_cameraspace; in vec3 LightDirection_tangentspace; in vec3 EyeDirection_tangentspace; // Ouput data out vec3 color; // Values that stay constant for the whole mesh. uniform sampler2D DiffuseTextureSampler; uniform sampler2D NormalTextureSampler; uniform sampler2D SpecularTextureSampler; uniform mat4 V; uniform mat4 M; uniform mat3 MV3x3; uniform vec3 LightPosition_worldspace; void main(){ // Light emission properties // You probably want to put them as uniforms vec3 LightColor = vec3(1,1,1); float LightPower = 40.0; // Material properties vec3 MaterialDiffuseColor = texture2D( DiffuseTextureSampler, vec2(UV.x,-UV.y) ).rgb; vec3 MaterialAmbientColor = vec3(0.1,0.1,0.1) * MaterialDiffuseColor; //vec3 MaterialSpecularColor = texture2D( SpecularTextureSampler, UV ).rgb * 0.3; vec3 MaterialSpecularColor = vec3(0.5,0.5,0.5); // Local normal, in tangent space. V tex coordinate is inverted because normal map is in TGA (not in DDS) for better quality vec3 TextureNormal_tangentspace = normalize(texture2D( NormalTextureSampler, vec2(UV.x,-UV.y) ).rgb*2.0 - 1.0); // Distance to the light float distance = length( LightPosition_worldspace - Position_worldspace ); // Normal of the computed fragment, in camera space vec3 n = TextureNormal_tangentspace; // Direction of the light (from the fragment to the light) vec3 l = normalize(LightDirection_tangentspace); // Cosine of the angle between the normal and the light direction, // clamped above 0 // - light is at the vertical of the triangle -> 1 // - light is perpendicular to the triangle -> 0 // - light is behind the triangle -> 0 float cosTheta = clamp( dot( n,l ), 0,1 ); // Eye vector (towards the camera) vec3 E = normalize(EyeDirection_tangentspace); // Direction in which the triangle reflects the light vec3 R = reflect(-l,n); // Cosine of the angle between the Eye vector and the Reflect vector, // clamped to 0 // - Looking into the reflection -> 1 // - Looking elsewhere -> < 1 float cosAlpha = clamp( dot( E,R ), 0,1 ); color = // Ambient : simulates indirect lighting MaterialAmbientColor + // Diffuse : "color" of the object MaterialDiffuseColor * LightColor * LightPower * cosTheta / (distance*distance) + // Specular : reflective highlight, like a mirror MaterialSpecularColor * LightColor * LightPower * pow(cosAlpha,5) / (distance*distance); //color.xyz = E; //color.xyz = LightDirection_tangentspace; //color.xyz = EyeDirection_tangentspace; } I have replaced the original color value by EyeDirection_tangentspace vector and then I got other strange effect but I can not link the image (not eunogh reputation) Is it possible that with this shaders is something wrong, or maybe in other place in my code e.g with my matrices? SOLVED Solved... 3 days needed for changing one letter from this: glBindBuffer(GL_ARRAY_BUFFER, vbo); glVertexAttribPointer ( 4, // attribute 3, // size GL_FLOAT, // type GL_FALSE, // normalized? sizeof(VboVertex), // stride (void*)(12*sizeof(float)) // array buffer offset ); to this: glBindBuffer(GL_ARRAY_BUFFER, vbo); glVertexAttribPointer ( 4, // attribute 3, // size GL_FLOAT, // type GL_FALSE, // normalized? sizeof(VboVertex), // stride (void*)(11*sizeof(float)) // array buffer offset ); see difference? :)

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HLSL/XNA Ambient light texture mixed up with multi pass lighting

- by Manu-EPITA

I've been having some troubles lately with lighting. I have found a source on google which is working pretty good on the example. However, when I try to implement it to my current project, I am getting some very weird bugs. The main one is that my textures are "mixed up" when I only activate the ambient light, which means that a model gets the texture of another one . I am using the same effect for every meshes of my models. I guess this could be the problem, but I don't really know how to "reset" an effect for a new model. Is it possible? Here is my shader: float4x4 WVP; float4x4 WVP; float3x3 World; float3 Ke; float3 Ka; float3 Kd; float3 Ks; float specularPower; float3 globalAmbient; float3 lightColor; float3 eyePosition; float3 lightDirection; float3 lightPosition; float spotPower; texture2D Texture; sampler2D texSampler = sampler_state { Texture = <Texture>; MinFilter = anisotropic; MagFilter = anisotropic; MipFilter = linear; MaxAnisotropy = 16; }; struct VertexShaderInput { float4 Position : POSITION0; float2 Texture : TEXCOORD0; float3 Normal : NORMAL0; }; struct VertexShaderOutput { float4 Position : POSITION0; float2 Texture : TEXCOORD0; float3 PositionO: TEXCOORD1; float3 Normal : NORMAL0; }; VertexShaderOutput VertexShaderFunction(VertexShaderInput input) { VertexShaderOutput output; output.Position = mul(input.Position, WVP); output.Normal = input.Normal; output.PositionO = input.Position.xyz; output.Texture = input.Texture; return output; } float4 PSAmbient(VertexShaderOutput input) : COLOR0 { return float4(Ka*globalAmbient + Ke,1) * tex2D(texSampler,input.Texture); } float4 PSDirectionalLight(VertexShaderOutput input) : COLOR0 { //Difuze float3 L = normalize(-lightDirection); float diffuseLight = max(dot(input.Normal,L), 0); float3 diffuse = Kd*lightColor*diffuseLight; //Specular float3 V = normalize(eyePosition - input.PositionO); float3 H = normalize(L + V); float specularLight = pow(max(dot(input.Normal,H),0),specularPower); if(diffuseLight<=0) specularLight=0; float3 specular = Ks * lightColor * specularLight; //sum all light components float3 light = diffuse + specular; return float4(light,1) * tex2D(texSampler,input.Texture); } technique MultiPassLight { pass Ambient { VertexShader = compile vs_3_0 VertexShaderFunction(); PixelShader = compile ps_3_0 PSAmbient(); } pass Directional { PixelShader = compile ps_3_0 PSDirectionalLight(); } } And here is how I actually apply my effects: public void ApplyLights(ModelMesh mesh, Matrix world, Texture2D modelTexture, Camera camera, Effect effect, GraphicsDevice graphicsDevice) { graphicsDevice.BlendState = BlendState.Opaque; effect.CurrentTechnique.Passes["Ambient"].Apply(); foreach (ModelMeshPart part in mesh.MeshParts) { graphicsDevice.SetVertexBuffer(part.VertexBuffer); graphicsDevice.Indices = part.IndexBuffer; // Texturing graphicsDevice.BlendState = BlendState.AlphaBlend; if (modelTexture != null) { effect.Parameters["Texture"].SetValue( modelTexture ); } graphicsDevice.DrawIndexedPrimitives( PrimitiveType.TriangleList, part.VertexOffset, 0, part.NumVertices, part.StartIndex, part.PrimitiveCount ); // Applying our shader to all the mesh parts effect.Parameters["WVP"].SetValue( world * camera.View * camera.Projection ); effect.Parameters["World"].SetValue(world); effect.Parameters["eyePosition"].SetValue( camera.Position ); graphicsDevice.BlendState = BlendState.Additive; // Drawing lights foreach (DirectionalLight light in DirectionalLights) { effect.Parameters["lightColor"].SetValue(light.Color.ToVector3()); effect.Parameters["lightDirection"].SetValue(light.Direction); // Applying changes and drawing them effect.CurrentTechnique.Passes["Directional"].Apply(); graphicsDevice.DrawIndexedPrimitives( PrimitiveType.TriangleList, part.VertexOffset, 0, part.NumVertices, part.StartIndex, part.PrimitiveCount ); } } I am also applying this when loading the effect: effect.Parameters["lightColor"].SetValue(Color.White.ToVector3()); effect.Parameters["globalAmbient"].SetValue(Color.White.ToVector3()); effect.Parameters["Ke"].SetValue(0.0f); effect.Parameters["Ka"].SetValue(0.01f); effect.Parameters["Kd"].SetValue(1.0f); effect.Parameters["Ks"].SetValue(0.3f); effect.Parameters["specularPower"].SetValue(100); Thank you very much UPDATE: I tried to load an effect for each model when drawing, but it doesn't seem to have changed anything. I suppose it is because XNA detects that the effect has already been loaded before and doesn't want to load a new one. Any idea why?

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Matplotlib plotting non uniform data in 3D surface

- by Raj Tendulkar

I have a simple code to plot the points in 3D for Matplotlib as below - from mpl_toolkits.mplot3d import axes3d import matplotlib.pyplot as plt import numpy as np from numpy import genfromtxt import csv fig = plt.figure() ax = fig.add_subplot(111, projection='3d') my_data = genfromtxt('points1.csv', delimiter=',') points1X = my_data[:,0] points1Y = my_data[:,1] points1Z = my_data[:,2] ## I remove the header of the CSV File. points1X = np.delete(points1X, 0) points1Y = np.delete(points1Y, 0) points1Z = np.delete(points1Z, 0) # Convert the array to 1D array points1X = np.reshape(points1X,points1X.size) points1Y = np.reshape(points1Y,points1Y.size) points1Z = np.reshape(points1Z,points1Z.size) my_data = genfromtxt('points2.csv', delimiter=',') points2X = my_data[:,0] points2Y = my_data[:,1] points2Z = my_data[:,2] ## I remove the header of the CSV File. points2X = np.delete(points2X, 0) points2Y = np.delete(points2Y, 0) points2Z = np.delete(points2Z, 0) # Convert the array to 1D array points2X = np.reshape(points2X,points2X.size) points2Y = np.reshape(points2Y,points2Y.size) points2Z = np.reshape(points2Z,points2Z.size) ax.plot(points1X, points1Y, points1Z, 'd', markersize=8, markerfacecolor='red', label='points1') ax.plot(points2X, points2Y, points2Z, 'd', markersize=8, markerfacecolor='blue', label='points2') plt.show() My problem is that I tried to make a decent surface plot out of these data points that I have. I already tried to use ax.plot_surface() function to make it look nice. For this I eliminated some points, and recalculated the matrix kind of input needed by this function. However, the graph I generated was far more difficult to interpret and understand. So there might be 2 possibilities: either I am not using the function correctly, or otherwise, the data I am trying to plot is not good for the surface plot. What I was expecting was 3D graph which would have an effect similar to that we have of 3D pie chart. We see that one piece (that which is extracted out) is part of another piece. I was not expecting it to be exactly same like that, but some kind of effect like that. What I would like to ask is: Do you think it will be possible to make such 3D graph? Is there any way better, I could express my data in 3 dimension? Here are the 2 files - points1.csv Dim1,Dim2,Dim3 3,8,1 3,8,2 3,8,3 3,8,4 3,8,5 3,9,1 3,9,2 3,9,3 3,9,4 3,9,5 3,10,1 3,10,2 3,10,3 3,10,4 3,10,5 3,11,1 3,11,2 3,11,3 3,11,4 3,11,5 3,12,1 3,12,2 3,13,1 3,13,2 3,14,1 3,14,2 3,15,1 3,15,2 3,16,1 3,16,2 3,17,1 3,17,2 3,18,1 3,18,2 4,8,1 4,8,2 4,8,3 4,8,4 4,8,5 4,9,1 4,9,2 4,9,3 4,9,4 4,9,5 4,10,1 4,10,2 4,10,3 4,10,4 4,10,5 4,11,1 4,11,2 4,11,3 4,11,4 4,11,5 4,12,1 4,13,1 4,14,1 4,15,1 4,16,1 4,17,1 4,18,1 5,8,1 5,8,2 5,8,3 5,8,4 5,8,5 5,9,1 5,9,2 5,9,3 5,9,4 5,9,5 5,10,1 5,10,2 5,10,3 5,10,4 5,10,5 5,11,1 5,11,2 5,11,3 5,11,4 5,11,5 5,12,1 5,13,1 5,14,1 5,15,1 5,16,1 5,17,1 5,18,1 6,8,1 6,8,2 6,8,3 6,8,4 6,8,5 6,9,1 6,9,2 6,9,3 6,9,4 6,9,5 6,10,1 6,11,1 6,12,1 6,13,1 6,14,1 6,15,1 6,16,1 6,17,1 6,18,1 7,8,1 7,8,2 7,8,3 7,8,4 7,8,5 7,9,1 7,9,2 7,9,3 7,9,4 7,9,5 and points2.csv Dim1,Dim2,Dim3 3,12,3 3,12,4 3,12,5 3,13,3 3,13,4 3,13,5 3,14,3 3,14,4 3,14,5 3,15,3 3,15,4 3,15,5 3,16,3 3,16,4 3,16,5 3,17,3 3,17,4 3,17,5 3,18,3 3,18,4 3,18,5 4,12,2 4,12,3 4,12,4 4,12,5 4,13,2 4,13,3 4,13,4 4,13,5 4,14,2 4,14,3 4,14,4 4,14,5 4,15,2 4,15,3 4,15,4 4,15,5 4,16,2 4,16,3 4,16,4 4,16,5 4,17,2 4,17,3 4,17,4 4,17,5 4,18,2 4,18,3 4,18,4 4,18,5 5,12,2 5,12,3 5,12,4 5,12,5 5,13,2 5,13,3 5,13,4 5,13,5 5,14,2 5,14,3 5,14,4 5,14,5 5,15,2 5,15,3 5,15,4 5,15,5 5,16,2 5,16,3 5,16,4 5,16,5 5,17,2 5,17,3 5,17,4 5,17,5 5,18,2 5,18,3 5,18,4 5,18,5 6,10,2 6,10,3 6,10,4 6,10,5 6,11,2 6,11,3 6,11,4 6,11,5 6,12,2 6,12,3 6,12,4 6,12,5 6,13,2 6,13,3 6,13,4 6,13,5 6,14,2 6,14,3 6,14,4 6,14,5 6,15,2 6,15,3 6,15,4 6,15,5 6,16,2 6,16,3 6,16,4 6,16,5 6,17,2 6,17,3 6,17,4 6,17,5 6,18,2 6,18,3 6,18,4 6,18,5 7,10,1 7,10,2 7,10,3 7,10,4 7,10,5 7,11,1 7,11,2 7,11,3 7,11,4 7,11,5 7,12,1 7,12,2 7,12,3 7,12,4 7,12,5 7,13,1 7,13,2 7,13,3 7,13,4 7,13,5 7,14,1 7,14,2 7,14,3 7,14,4 7,14,5 7,15,1 7,15,2 7,15,3 7,15,4 7,15,5 7,16,1 7,16,2 7,16,3 7,16,4 7,16,5 7,17,1 7,17,2 7,17,3 7,17,4 7,17,5 7,18,1 7,18,2 7,18,3 7,18,4 7,18,5

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How to find and fix performance problems in ORM powered applications

- by FransBouma

Once in a while we get requests about how to fix performance problems with our framework. As it comes down to following the same steps and looking into the same things every single time, I decided to write a blogpost about it instead, so more people can learn from this and solve performance problems in their O/R mapper powered applications. In some parts it's focused on LLBLGen Pro but it's also usable for other O/R mapping frameworks, as the vast majority of performance problems in O/R mapper powered applications are not specific for a certain O/R mapper framework. Too often, the developer looks at the wrong part of the application, trying to fix what isn't a problem in that part, and getting frustrated that 'things are so slow with <insert your favorite framework X here>'. I'm in the O/R mapper business for a long time now (almost 10 years, full time) and as it's a small world, we O/R mapper developers know almost all tricks to pull off by now: we all know what to do to make task ABC faster and what compromises (because there are almost always compromises) to deal with if we decide to make ABC faster that way. Some O/R mapper frameworks are faster in X, others in Y, but you can be sure the difference is mainly a result of a compromise some developers are willing to deal with and others aren't. That's why the O/R mapper frameworks on the market today are different in many ways, even though they all fetch and save entities from and to a database. I'm not suggesting there's no room for improvement in today's O/R mapper frameworks, there always is, but it's not a matter of 'the slowness of the application is caused by the O/R mapper' anymore. Perhaps query generation can be optimized a bit here, row materialization can be optimized a bit there, but it's mainly coming down to milliseconds. Still worth it if you're a framework developer, but it's not much compared to the time spend inside databases and in user code: if a complete fetch takes 40ms or 50ms (from call to entity object collection), it won't make a difference for your application as that 10ms difference won't be noticed. That's why it's very important to find the real locations of the problems so developers can fix them properly and don't get frustrated because their quest to get a fast, performing application failed. Performance tuning basics and rules Finding and fixing performance problems in any application is a strict procedure with four prescribed steps: isolate, analyze, interpret and fix, in that order. It's key that you don't skip a step nor make assumptions: these steps help you find the reason of a problem which seems to be there, and how to fix it or leave it as-is. Skipping a step, or when you assume things will be bad/slow without doing analysis will lead to the path of premature optimization and won't actually solve your problems, only create new ones. The most important rule of finding and fixing performance problems in software is that you have to understand what 'performance problem' actually means. Most developers will say "when a piece of software / code is slow, you have a performance problem". But is that actually the case? If I write a Linq query which will aggregate, group and sort 5 million rows from several tables to produce a resultset of 10 rows, it might take more than a couple of milliseconds before that resultset is ready to be consumed by other logic. If I solely look at the Linq query, the code consuming the resultset of the 10 rows and then look at the time it takes to complete the whole procedure, it will appear to me to be slow: all that time taken to produce and consume 10 rows? But if you look closer, if you analyze and interpret the situation, you'll see it does a tremendous amount of work, and in that light it might even be extremely fast. With every performance problem you encounter, always do realize that what you're trying to solve is perhaps not a technical problem at all, but a perception problem. The second most important rule you have to understand is based on the old saying "Penny wise, Pound Foolish": the part which takes e.g. 5% of the total time T for a given task isn't worth optimizing if you have another part which takes a much larger part of the total time T for that same given task. Optimizing parts which are relatively insignificant for the total time taken is not going to bring you better results overall, even if you totally optimize that part away. This is the core reason why analysis of the complete set of application parts which participate in a given task is key to being successful in solving performance problems: No analysis -> no problem -> no solution. One warning up front: hunting for performance will always include making compromises. Fast software can be made maintainable, but if you want to squeeze as much performance out of your software, you will inevitably be faced with the dilemma of compromising one or more from the group {readability, maintainability, features} for the extra performance you think you'll gain. It's then up to you to decide whether it's worth it. In almost all cases it's not. The reason for this is simple: the vast majority of performance problems can be solved by implementing the proper algorithms, the ones with proven Big O-characteristics so you know the performance you'll get plus you know the algorithm will work. The time taken by the algorithm implementing code is inevitable: you already implemented the best algorithm. You might find some optimizations on the technical level but in general these are minor. Let's look at the four steps to see how they guide us through the quest to find and fix performance problems. Isolate The first thing you need to do is to isolate the areas in your application which are assumed to be slow. For example, if your application is a web application and a given page is taking several seconds or even minutes to load, it's a good candidate to check out. It's important to start with the isolate step because it allows you to focus on a single code path per area with a clear begin and end and ignore the rest. The rest of the steps are taken per identified problematic area. Keep in mind that isolation focuses on tasks in an application, not code snippets. A task is something that's started in your application by either another task or the user, or another program, and has a beginning and an end. You can see a task as a piece of functionality offered by your application. Analyze Once you've determined the problem areas, you have to perform analysis on the code paths of each area, to see where the performance problems occur and which areas are not the problem. This is a multi-layered effort: an application which uses an O/R mapper typically consists of multiple parts: there's likely some kind of interface (web, webservice, windows etc.), a part which controls the interface and business logic, the O/R mapper part and the RDBMS, all connected with either a network or inter-process connections provided by the OS or other means. Each of these parts, including the connectivity plumbing, eat up a part of the total time it takes to complete a task, e.g. load a webpage with all orders of a given customer X. To understand which parts participate in the task / area we're investigating and how much they contribute to the total time taken to complete the task, analysis of each participating task is essential. Start with the code you wrote which starts the task, analyze the code and track the path it follows through your application. What does the code do along the way, verify whether it's correct or not. Analyze whether you have implemented the right algorithms in your code for this particular area. Remember we're looking at one area at a time, which means we're ignoring all other code paths, just the code path of the current problematic area, from begin to end and back. Don't dig in and start optimizing at the code level just yet. We're just analyzing. If your analysis reveals big architectural stupidity, it's perhaps a good idea to rethink the architecture at this point. For the rest, we're analyzing which means we collect data about what could be wrong, for each participating part of the complete application. Reviewing the code you wrote is a good tool to get deeper understanding of what is going on for a given task but ultimately it lacks precision and overview what really happens: humans aren't good code interpreters, computers are. We therefore need to utilize tools to get deeper understanding about which parts contribute how much time to the total task, triggered by which other parts and for example how many times are they called. There are two different kind of tools which are necessary: .NET profilers and O/R mapper / RDBMS profilers. .NET profiling .NET profilers (e.g. dotTrace by JetBrains or Ants by Red Gate software) show exactly which pieces of code are called, how many times they're called, and the time it took to run that piece of code, at the method level and sometimes even at the line level. The .NET profilers are essential tools for understanding whether the time taken to complete a given task / area in your application is consumed by .NET code, where exactly in your code, the path to that code, how many times that code was called by other code and thus reveals where hotspots are located: the areas where a solution can be found. Importantly, they also reveal which areas can be left alone: remember our penny wise pound foolish saying: if a profiler reveals that a group of methods are fast, or don't contribute much to the total time taken for a given task, ignore them. Even if the code in them is perhaps complex and looks like a candidate for optimization: you can work all day on that, it won't matter. As we're focusing on a single area of the application, it's best to start profiling right before you actually activate the task/area. Most .NET profilers support this by starting the application without starting the profiling procedure just yet. You navigate to the particular part which is slow, start profiling in the profiler, in your application you perform the actions which are considered slow, and afterwards you get a snapshot in the profiler. The snapshot contains the data collected by the profiler during the slow action, so most data is produced by code in the area to investigate. This is important, because it allows you to stay focused on a single area. O/R mapper and RDBMS profiling .NET profilers give you a good insight in the .NET side of things, but not in the RDBMS side of the application. As this article is about O/R mapper powered applications, we're also looking at databases, and the software making it possible to consume the database in your application: the O/R mapper. To understand which parts of the O/R mapper and database participate how much to the total time taken for task T, we need different tools. There are two kind of tools focusing on O/R mappers and database performance profiling: O/R mapper profilers and RDBMS profilers. For O/R mapper profilers, you can look at LLBLGen Prof by hibernating rhinos or the Linq to Sql/LLBLGen Pro profiler by Huagati. Hibernating rhinos also have profilers for other O/R mappers like NHibernate (NHProf) and Entity Framework (EFProf) and work the same as LLBLGen Prof. For RDBMS profilers, you have to look whether the RDBMS vendor has a profiler. For example for SQL Server, the profiler is shipped with SQL Server, for Oracle it's build into the RDBMS, however there are also 3rd party tools. Which tool you're using isn't really important, what's important is that you get insight in which queries are executed during the task / area we're currently focused on and how long they took. Here, the O/R mapper profilers have an advantage as they collect the time it took to execute the query from the application's perspective so they also collect the time it took to transport data across the network. This is important because a query which returns a massive resultset or a resultset with large blob/clob/ntext/image fields takes more time to get transported across the network than a small resultset and a database profiler doesn't take this into account most of the time. Another tool to use in this case, which is more low level and not all O/R mappers support it (though LLBLGen Pro and NHibernate as well do) is tracing: most O/R mappers offer some form of tracing or logging system which you can use to collect the SQL generated and executed and often also other activity behind the scenes. While tracing can produce a tremendous amount of data in some cases, it also gives insight in what's going on. Interpret After we've completed the analysis step it's time to look at the data we've collected. We've done code reviews to see whether we've done anything stupid and which parts actually take place and if the proper algorithms have been implemented. We've done .NET profiling to see which parts are choke points and how much time they contribute to the total time taken to complete the task we're investigating. We've performed O/R mapper profiling and RDBMS profiling to see which queries were executed during the task, how many queries were generated and executed and how long they took to complete, including network transportation. All this data reveals two things: which parts are big contributors to the total time taken and which parts are irrelevant. Both aspects are very important. The parts which are irrelevant (i.e. don't contribute significantly to the total time taken) can be ignored from now on, we won't look at them. The parts which contribute a lot to the total time taken are important to look at. We now have to first look at the .NET profiler results, to see whether the time taken is consumed in our own code, in .NET framework code, in the O/R mapper itself or somewhere else. For example if most of the time is consumed by DbCommand.ExecuteReader, the time it took to complete the task is depending on the time the data is fetched from the database. If there was just 1 query executed, according to tracing or O/R mapper profilers / RDBMS profilers, check whether that query is optimal, uses indexes or has to deal with a lot of data. Interpret means that you follow the path from begin to end through the data collected and determine where, along the path, the most time is contributed. It also means that you have to check whether this was expected or is totally unexpected. My previous example of the 10 row resultset of a query which groups millions of rows will likely reveal that a long time is spend inside the database and almost no time is spend in the .NET code, meaning the RDBMS part contributes the most to the total time taken, the rest is compared to that time, irrelevant. Considering the vastness of the source data set, it's expected this will take some time. However, does it need tweaking? Perhaps all possible tweaks are already in place. In the interpret step you then have to decide that further action in this area is necessary or not, based on what the analysis results show: if the analysis results were unexpected and in the area where the most time is contributed to the total time taken is room for improvement, action should be taken. If not, you can only accept the situation and move on. In all cases, document your decision together with the analysis you've done. If you decide that the perceived performance problem is actually expected due to the nature of the task performed, it's essential that in the future when someone else looks at the application and starts asking questions you can answer them properly and new analysis is only necessary if situations changed. Fix After interpreting the analysis results you've concluded that some areas need adjustment. This is the fix step: you're actively correcting the performance problem with proper action targeted at the real cause. In many cases related to O/R mapper powered applications it means you'll use different features of the O/R mapper to achieve the same goal, or apply optimizations at the RDBMS level. It could also mean you apply caching inside your application (compromise memory consumption over performance) to avoid unnecessary re-querying data and re-consuming the results. After applying a change, it's key you re-do the analysis and interpretation steps: compare the results and expectations with what you had before, to see whether your actions had any effect or whether it moved the problem to a different part of the application. Don't fall into the trap to do partly analysis: do the full analysis again: .NET profiling and O/R mapper / RDBMS profiling. It might very well be that the changes you've made make one part faster but another part significantly slower, in such a way that the overall problem hasn't changed at all. Performance tuning is dealing with compromises and making choices: to use one feature over the other, to accept a higher memory footprint, to go away from the strict-OO path and execute queries directly onto the RDBMS, these are choices and compromises which will cross your path if you want to fix performance problems with respect to O/R mappers or data-access and databases in general. In most cases it's not a big issue: alternatives are often good choices too and the compromises aren't that hard to deal with. What is important is that you document why you made a choice, a compromise: which analysis data, which interpretation led you to the choice made. This is key for good maintainability in the years to come. Most common performance problems with O/R mappers Below is an incomplete list of common performance problems related to data-access / O/R mappers / RDBMS code. It will help you with fixing the hotspots you found in the interpretation step. SELECT N+1: (Lazy-loading specific). Lazy loading triggered performance bottlenecks. Consider a list of Orders bound to a grid. You have a Field mapped onto a related field in Order, Customer.CompanyName. Showing this column in the grid will make the grid fetch (indirectly) for each row the Customer row. This means you'll get for the single list not 1 query (for the orders) but 1+(the number of orders shown) queries. To solve this: use eager loading using a prefetch path to fetch the customers with the orders. SELECT N+1 is easy to spot with an O/R mapper profiler or RDBMS profiler: if you see a lot of identical queries executed at once, you have this problem. Prefetch paths using many path nodes or sorting, or limiting. Eager loading problem. Prefetch paths can help with performance, but as 1 query is fetched per node, it can be the number of data fetched in a child node is bigger than you think. Also consider that data in every node is merged on the client within the parent. This is fast, but it also can take some time if you fetch massive amounts of entities. If you keep fetches small, you can use tuning parameters like the ParameterizedPrefetchPathThreshold setting to get more optimal queries. Deep inheritance hierarchies of type Target Per Entity/Type. If you use inheritance of type Target per Entity / Type (each type in the inheritance hierarchy is mapped onto its own table/view), fetches will join subtype- and supertype tables in many cases, which can lead to a lot of performance problems if the hierarchy has many types. With this problem, keep inheritance to a minimum if possible, or switch to a hierarchy of type Target Per Hierarchy, which means all entities in the inheritance hierarchy are mapped onto the same table/view. Of course this has its own set of drawbacks, but it's a compromise you might want to take. Fetching massive amounts of data by fetching large lists of entities. LLBLGen Pro supports paging (and limiting the # of rows returned), which is often key to process through large sets of data. Use paging on the RDBMS if possible (so a query is executed which returns only the rows in the page requested). When using paging in a web application, be sure that you switch server-side paging on on the datasourcecontrol used. In this case, paging on the grid alone is not enough: this can lead to fetching a lot of data which is then loaded into the grid and paged there. Keep note that analyzing queries for paging could lead to the false assumption that paging doesn't occur, e.g. when the query contains a field of type ntext/image/clob/blob and DISTINCT can't be applied while it should have (e.g. due to a join): the datareader will do DISTINCT filtering on the client. this is a little slower but it does perform paging functionality on the data-reader so it won't fetch all rows even if the query suggests it does. Fetch massive amounts of data because blob/clob/ntext/image fields aren't excluded. LLBLGen Pro supports field exclusion for queries. You can exclude fields (also in prefetch paths) per query to avoid fetching all fields of an entity, e.g. when you don't need them for the logic consuming the resultset. Excluding fields can greatly reduce the amount of time spend on data-transport across the network. Use this optimization if you see that there's a big difference between query execution time on the RDBMS and the time reported by the .NET profiler for the ExecuteReader method call. Doing client-side aggregates/scalar calculations by consuming a lot of data. If possible, try to formulate a scalar query or group by query using the projection system or GetScalar functionality of LLBLGen Pro to do data consumption on the RDBMS server. It's far more efficient to process data on the RDBMS server than to first load it all in memory, then traverse the data in-memory to calculate a value. Using .ToList() constructs inside linq queries. It might be you use .ToList() somewhere in a Linq query which makes the query be run partially in-memory. Example: var q = from c in metaData.Customers.ToList() where c.Country=="Norway" select c; This will actually fetch all customers in-memory and do an in-memory filtering, as the linq query is defined on an IEnumerable<T>, and not on the IQueryable<T>. Linq is nice, but it can often be a bit unclear where some parts of a Linq query might run. Fetching all entities to delete into memory first. To delete a set of entities it's rather inefficient to first fetch them all into memory and then delete them one by one. It's more efficient to execute a DELETE FROM ... WHERE query on the database directly to delete the entities in one go. LLBLGen Pro supports this feature, and so do some other O/R mappers. It's not always possible to do this operation in the context of an O/R mapper however: if an O/R mapper relies on a cache, these kind of operations are likely not supported because they make it impossible to track whether an entity is actually removed from the DB and thus can be removed from the cache. Fetching all entities to update with an expression into memory first. Similar to the previous point: it is more efficient to update a set of entities directly with a single UPDATE query using an expression instead of fetching the entities into memory first and then updating the entities in a loop, and afterwards saving them. It might however be a compromise you don't want to take as it is working around the idea of having an object graph in memory which is manipulated and instead makes the code fully aware there's a RDBMS somewhere. Conclusion Performance tuning is almost always about compromises and making choices. It's also about knowing where to look and how the systems in play behave and should behave. The four steps I provided should help you stay focused on the real problem and lead you towards the solution. Knowing how to optimally use the systems participating in your own code (.NET framework, O/R mapper, RDBMS, network/services) is key for success as well as knowing what's going on inside the application you built. I hope you'll find this guide useful in tracking down performance problems and dealing with them in a useful way.

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TemplateBinding with Converter - what is wrong?

- by MartyIX

I'm creating a game desk. I wanted to specify field size (one field is a square) as a attached property and with this data set value of ViewPort which would draw 2x2 matrix (and tile mode would do the rest of game desk). I'm quite at loss what is wrong because the binding doesn't work. Testing line in XAML for the behaviour I would like to have: <DrawingBrush Viewport="0,0,100,100" ViewportUnits="Absolute" TileMode="None"> The game desk is based on this sample of DrawingPaint: http://msdn.microsoft.com/en-us/library/aa970904.aspx (an image is here) XAML: <Window x:Class="Sokoban.Window1" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:local="clr-namespace:Sokoban" Title="Window1" Height="559" Width="419"> <Window.Resources> <local:FieldSizeToRectConverter x:Key="fieldSizeConverter" /> <Style x:Key="GameDesk" TargetType="{x:Type Rectangle}"> <Setter Property="local:GameDeskProperties.FieldSize" Value="50" /> <Setter Property="Fill"> <Setter.Value>  <DrawingBrush Viewport="{TemplateBinding local:GameDeskProperties.FieldSize, Converter={StaticResource fieldSizeConverter}}" ViewportUnits="Absolute" TileMode="None"> <DrawingBrush.Drawing> <DrawingGroup> <GeometryDrawing Brush="CornflowerBlue"> <GeometryDrawing.Geometry> <RectangleGeometry Rect="0,0,100,100" /> </GeometryDrawing.Geometry> </GeometryDrawing> <GeometryDrawing Brush="Azure"> <GeometryDrawing.Geometry> <GeometryGroup> <RectangleGeometry Rect="0,0,50,50" /> <RectangleGeometry Rect="50,50,50,50" /> </GeometryGroup> </GeometryDrawing.Geometry> </GeometryDrawing> </DrawingGroup> </DrawingBrush.Drawing> </DrawingBrush> </Setter.Value> </Setter> </Style> </Window.Resources> <StackPanel> <Rectangle Style="{StaticResource GameDesk}" Width="300" Height="150" /> </StackPanel> </Window> Converter and property definition: using System; using System.Collections.Generic; using System.Text; using System.Windows.Controls; using System.Windows; using System.Diagnostics; using System.Windows.Data; namespace Sokoban { public class GameDeskProperties : Panel { public static readonly DependencyProperty FieldSizeProperty; static GameDeskProperties() { PropertyChangedCallback fieldSizeChanged = new PropertyChangedCallback(OnFieldSizeChanged); PropertyMetadata fieldSizeMetadata = new PropertyMetadata(50, fieldSizeChanged); FieldSizeProperty = DependencyProperty.RegisterAttached("FieldSize", typeof(int), typeof(GameDeskProperties), fieldSizeMetadata); } public static int GetFieldSize(DependencyObject target) { return (int)target.GetValue(FieldSizeProperty); } public static void SetFieldSize(DependencyObject target, int value) { target.SetValue(FieldSizeProperty, value); } static void OnFieldSizeChanged(DependencyObject target, DependencyPropertyChangedEventArgs e) { Debug.WriteLine("FieldSize just changed: " + e.NewValue); } } [ValueConversion(/* sourceType */ typeof(int), /* targetType */ typeof(Rect))] public class FieldSizeToRectConverter : IValueConverter { public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture) { Debug.Assert(targetType == typeof(int)); int fieldSize = int.Parse(value.ToString()); return new Rect(0, 0, 2 * fieldSize, 2 * fieldSize); } public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture) { // should not be called in our example throw new NotImplementedException(); } } }

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Rendering a random generated maze in WinForms.NET

- by Claus Jørgensen

Hi I'm trying to create a maze-generator, and for this I have implemented the Randomized Prim's Algorithm in C#. However, the result of the generation is invalid. I can't figure out if it's my rendering, or the implementation that's invalid. So for starters, I'd like to have someone take a look at the implementation: maze is a matrix of cells. var cell = maze[0, 0]; cell.Connected = true; var walls = new HashSet<MazeWall>(cell.Walls); while (walls.Count > 0) { var randomWall = walls.GetRandom(); var randomCell = randomWall.A.Connected ? randomWall.B : randomWall.A; if (!randomCell.Connected) { randomWall.IsPassage = true; randomCell.Connected = true; foreach (var wall in randomCell.Walls) walls.Add(wall); } walls.Remove(randomWall); } Here's a example on the rendered result: Edit Ok, lets have a look at the rendering part then: private void MazePanel_Paint(object sender, PaintEventArgs e) { int size = 20; int cellSize = 10; MazeCell[,] maze = RandomizedPrimsGenerator.Generate(size); mazePanel.Size = new Size( size * cellSize + 1, size * cellSize + 1 ); e.Graphics.DrawRectangle(Pens.Blue, 0, 0, size * cellSize, size * cellSize ); for (int y = 0; y < size; y++) for (int x = 0; x < size; x++) { foreach(var wall in maze[x, y].Walls.Where(w => !w.IsPassage)) { if (wall.Direction == MazeWallOrientation.Horisontal) { e.Graphics.DrawLine(Pens.Blue, x * cellSize, y * cellSize, x * cellSize + cellSize, y * cellSize ); } else { e.Graphics.DrawLine(Pens.Blue, x * cellSize, y * cellSize, x * cellSize, y * cellSize + cellSize ); } } } } And I guess, to understand this we need to see the MazeCell and MazeWall class: namespace MazeGenerator.Maze { class MazeCell { public int Column { get; set; } public int Row { get; set; } public bool Connected { get; set; } private List<MazeWall> walls = new List<MazeWall>(); public List<MazeWall> Walls { get { return walls; } set { walls = value; } } public MazeCell() { this.Connected = false; } public void AddWall(MazeCell b) { walls.Add(new MazeWall(this, b)); } } enum MazeWallOrientation { Horisontal, Vertical, Undefined } class MazeWall : IEquatable<MazeWall> { public IEnumerable<MazeCell> Cells { get { yield return CellA; yield return CellB; } } public MazeCell CellA { get; set; } public MazeCell CellB { get; set; } public bool IsPassage { get; set; } public MazeWallOrientation Direction { get { if (CellA.Column == CellB.Column) { return MazeWallOrientation.Horisontal; } else if (CellA.Row == CellB.Row) { return MazeWallOrientation.Vertical; } else { return MazeWallOrientation.Undefined; } } } public MazeWall(MazeCell a, MazeCell b) { this.CellA = a; this.CellB = b; a.Walls.Add(this); b.Walls.Add(this); IsPassage = false; } #region IEquatable<MazeWall> Members public bool Equals(MazeWall other) { return (this.CellA == other.CellA) && (this.CellB == other.CellB); } #endregion } }

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Is this question too hard for a seasoned C++ architect?

- by Monomer

Background Information We're looking to hire a seasoned C++ architect (10+years dev, of which at least 6years must be C++ ) for a high frequency trading platform. Job advert says STL, Boost proficiency is a must with preferences to modern uses of C++. The company I work for is a Fortune 500 IB (aka finance industry), it requires passes in all the standard SHL tests (numeric, vocab, spatial etc) before interviews can commence. Everyone on the team was given the task of coming up with one question to ask the candidates during a written/typed test, please note this is the second test provided to the candidates, the first being Advanced IKM C++ test, done in the offices supervised and without internet access. People passing that do the second test. After roughly 70 candidates, my question has been determined to be statistically the worst performing - aka least number of people attempted it, furthermore even less people were able to give meaningful answers. Please note, the second test is not timed, the candidate can literally take as long as they like (we've had one person take roughly 10.5hrs) My question to SO is this, after SHL and IKM adv c++ tests, backed up with at least 6+ years C++ development experience, is it still ok not to be able to even comment about let alone come up with some loose strategy for solving the following question. The Question There is a class C with methods foo, boo, boo_and_foo and foo_and_boo. Each method takes i,j,k and l clock cycles respectively, where i < j, k < i+j and l < i+j. class C { public: int foo() {...} int boo() {...} int boo_and_foo() {...} int foo_and_boo() {...} }; In code one might write: C c; . . int i = c.foo() + c.boo(); But it would be better to have: int i = c.foo_and_boo(); What changes or techniques could one make to the definition of C, that would allow similar syntax of the original usage, but instead have the compiler generate the latter. Note that foo and boo are not commutative. Possible Solution We were basically looking for an expression templates based approach, and were willing to give marks to anyone who had even hinted or used the phrase or related terminology. We got only two people that used the wording, but weren't able to properly describe how they accomplish the task in detail. We use such techniques all over the place, due to the use of various mathematical operators for matrix and vector based calculations, for example to decide when to use IPP or hand woven implementations at compile time for a particular architecture and many other things. The particular area of software development requires microsecond response times. I believe could/should be able to teach a junior such techniques, but given the assumed caliber of candidates I expected a little more. Is this really a difficult question? Should it be removed? Or are we just not seeing the right candidates?

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Matlab: Optimization by perturbing variable

- by S_H

My main script contains following code: %# Grid and model parameters nModel=50; nModel_want=1; nI_grid1=5; Nth=1; nRow.Scale1=5; nCol.Scale1=5; nRow.Scale2=5^2; nCol.Scale2=5^2; theta = 90; % degrees a_minor = 2; % range along minor direction a_major = 5; % range along major direction sill = var(reshape(Deff_matrix_NthModel,nCell.Scale1,1)); % variance of the coarse data matrix of size nRow.Scale1 X nCol.Scale1 %# Covariance computation % Scale 1 for ihRow = 1:nRow.Scale1 for ihCol = 1:nCol.Scale1 [cov.Scale1(ihRow,ihCol),heff.Scale1(ihRow,ihCol)] = general_CovModel(theta, ihCol, ihRow, a_minor, a_major, sill, 'Exp'); end end % Scale 2 for ihRow = 1:nRow.Scale2 for ihCol = 1:nCol.Scale2 [cov.Scale2(ihRow,ihCol),heff.Scale2(ihRow,ihCol)] = general_CovModel(theta, ihCol/(nCol.Scale2/nCol.Scale1), ihRow/(nRow.Scale2/nRow.Scale1), a_minor, a_major, sill/(nRow.Scale2*nCol.Scale2), 'Exp'); end end %# Scale-up of fine scale values by averaging [covAvg.Scale2,var_covAvg.Scale2,varNorm_covAvg.Scale2] = general_AverageProperty(nRow.Scale2/nRow.Scale1,nCol.Scale2/nCol.Scale1,1,nRow.Scale1,nCol.Scale1,1,cov.Scale2,1); I am using two functions, general_CovModel() and general_AverageProperty(), in my main script which are given as following: function [cov,h_eff] = general_CovModel(theta, hx, hy, a_minor, a_major, sill, mod_type) % mod_type should be in strings angle_rad = theta*(pi/180); % theta in degrees, angle_rad in radians R_theta = [sin(angle_rad) cos(angle_rad); -cos(angle_rad) sin(angle_rad)]; h = [hx; hy]; lambda = a_minor/a_major; D_lambda = [lambda 0; 0 1]; h_2prime = D_lambda*R_theta*h; h_eff = sqrt((h_2prime(1)^2)+(h_2prime(2)^2)); if strcmp(mod_type,'Sph')==1 || strcmp(mod_type,'sph') ==1 if h_eff<=a cov = sill - sill.*(1.5*(h_eff/a_minor)-0.5*((h_eff/a_minor)^3)); else cov = sill; end elseif strcmp(mod_type,'Exp')==1 || strcmp(mod_type,'exp') ==1 cov = sill-(sill.*(1-exp(-(3*h_eff)/a_minor))); elseif strcmp(mod_type,'Gauss')==1 || strcmp(mod_type,'gauss') ==1 cov = sill-(sill.*(1-exp(-((3*h_eff)^2/(a_minor^2))))); end and function [PropertyAvg,variance_PropertyAvg,NormVariance_PropertyAvg]=... general_AverageProperty(blocksize_row,blocksize_col,blocksize_t,... nUpscaledRow,nUpscaledCol,nUpscaledT,PropertyArray,omega) % This function computes average of a property and variance of that averaged % property using power averaging PropertyAvg=zeros(nUpscaledRow,nUpscaledCol,nUpscaledT); %# Average of property for k=1:nUpscaledT, for j=1:nUpscaledCol, for i=1:nUpscaledRow, sum=0; for a=1:blocksize_row, for b=1:blocksize_col, for c=1:blocksize_t, sum=sum+(PropertyArray((i-1)*blocksize_row+a,(j-1)*blocksize_col+b,(k-1)*blocksize_t+c).^omega); % add all the property values in 'blocksize_x','blocksize_y','blocksize_t' to one variable end end end PropertyAvg(i,j,k)=(sum/(blocksize_row*blocksize_col*blocksize_t)).^(1/omega); % take average of the summed property end end end %# Variance of averageed property variance_PropertyAvg=var(reshape(PropertyAvg,... nUpscaledRow*nUpscaledCol*nUpscaledT,1),1,1); %# Normalized variance of averageed property NormVariance_PropertyAvg=variance_PropertyAvg./(var(reshape(... PropertyArray,numel(PropertyArray),1),1,1)); Question: Using Matlab, I would like to optimize covAvg.Scale2 such that it matches closely with cov.Scale1 by perturbing/varying any (or all) of the following variables 1) a_minor 2) a_major 3) theta Thanks.

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Which option do you like the most?

- by spderosso

I need to show a list of movies ordered by the date they were registered in the system and the amount of comments users have made about them. E.g: Title | Register Date | # of comments Gladiator | 02-01-2010 | 30 Matrix | 01-02-2010 | 20 It is a web application that follows MVC. So, I have the object "Movie", there is a MovieManager interface that is used for retrieving/persisting data to the database and a servlet RecentlyAddedMovies.java that forwards to a .jsp to render the list. I will explain my problem by showing an example of how I am doing another similar task: Showing top ranked movies. Regarding the MovieManager: /** * Returns a collection of the x best-ranked movies * @param x the amount of movies to return * @return A collection of movies * @throws SQLException */ public Collection<Movie> getTopX(int x) throws SQLException; The servlet: public class Top5 extends HttpServlet{ @Override protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { MovieManager movManager = JDBCMovieManager.getInstance(); try { req.setAttribute("movies", movManager.getTopX(5)); } catch (SQLException e) { // TODO Auto-generated catch block e.printStackTrace(); } req.getRequestDispatcher("listMovies.jsp").forward(req, resp); } } And the listMovies.jsp has is some place something like: <c:forEach var="movie" items="${movies}"> ... <c:out value="${movie.title}"/> ... </c:forEach> The difference between the top5 problem and the problem I am trying to solve is that with the top5 thing all the data I needed to show in the view where part of the "Movie" object, so the MovieManager simply returned a Collection of Movies. Now, the MovieManager must retrieve an ordered list of (Movie, # of comments). The Movie object has a collection of Comment associated but of course, it lacks an instance variable with the length of that collection. The following things came into my mind: a) Create a MovieView object or something like that, that is only used by the "View" and "Controller" layer of the MVC which is not part of the "Model" in the sense that is used only for easy retrieval and display of information. This MovieView object will have a title, registerDate and # of Comments so the thing would look something like this: /** * Returns a collection of the x most recently added movies * @param x the amount of movies to return * @return A collection of movies * @throws SQLException */ public Collection<Movie2> getXRecentlyAddedMovies(int x) throws SQLException; The .jsp: <c:forEach var="movie2" items="${movies2}"> ... <c:out value="${movie2.title}"/> <c:out value="${movie2.registerDate}"/> <c:out value="${movie2.noOfComments}"/> ... </c:forEach> b) Add to the Collection the movie has, empty Comments (there is no actual need to retrieve all the comment data from the database) so that the comment's collection.size() will show the number of comments that movie has. (This sounds horrible to me) c) Add to the "Movie" object an instance field noOfComments with the setter and getter that will help with this type of cases even if, looking only from the object point of view, it is a redundant field since it already has a Collection that is ".size()"able . d) Make the MovieManager retrieve some structure like a Map or a Collection of a two component array or something like that that will contain both a Movie object and the associated number of comments and with JSLT iterate over it and show it accordingly.

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Why a graphics overflow problem as a result of a for loop?

- by sonny5

using System; using System.Drawing; using System.Collections; using System.ComponentModel; using System.Windows.Forms; using System.Data; using System.Drawing.Imaging; using System.Drawing.Drawing2D; public class Form1 : System.Windows.Forms.Form { public static float WXmin; public static float WYmin; public static float WXmax; public static float WYmax; public static int VXmin; public static int VYmin; public static int VXmax; public static int VYmax; public static float Wx; public static float Wy; public static float Vx; public static float Vy; public Form1() { InitializeComponent(); } private void InitializeComponent() { this.ClientSize = new System.Drawing.Size(400, 300); this.Text="Pass Args"; this.Paint += new System.Windows.Forms.PaintEventHandler(this.doLine); //this.Paint += new System.PaintEventHandler(this.eachCornerPix); //eachCornerPix(out Wx, out Wy, out Vx, out Vy); } static void Main() { Application.Run(new Form1()); } private void doLine(object sender, System.Windows.Forms.PaintEventArgs e) { Graphics g = e.Graphics; g.FillRectangle(Brushes.White, this.ClientRectangle); Pen p = new Pen(Color.Black); g.DrawLine(p, 0, 0, 100, 100); // draw DOWN in y, which is positive since no matrix called eachCornerPix(sender, e, out Wx, out Wy, out Vx, out Vy); p.Dispose(); } private void eachCornerPix (object sender, System.EventArgs e, out float Wx, out float Wy, out float Vx, out float Vy) { Wx = 0.0f; Wy = 0.0f; Vx = 0.0f; Vy = 0.0f; Graphics g = this.CreateGraphics(); Pen penBlu = new Pen(Color.Blue, 2); SolidBrush redBrush = new SolidBrush(Color.Red); int width = 2; // 1 pixel wide in x int height = 2; float [] Wxc = {0.100f, 5.900f, 5.900f, 0.100f}; float [] Wyc = {0.100f, 0.100f, 3.900f, 3.900f}; Console.WriteLine("Wxc[0] = {0}", Wxc[0]); Console.WriteLine("Wyc[3] = {0}", Wyc[3]); /* for (int i = 0; i<3; i++) { Wx = Wxc[i]; Wy = Wyc[i]; Vx = ((Wx - WXmin)*((VXmax-VXmin)+VXmin)/(WXmax-WXmin)); Vy = ((Wy - WYmin)*(VYmax-VYmin)/(WYmax-WYmin)+VYmin); Console.WriteLine("eachCornerPix Vx= {0}", Vx); Console.WriteLine("eachCornerPix Vy= {0}", Vy); g.FillRectangle(redBrush, Vx, Vy, width, height); } */ // What is there about this for loop that will not run? // When the comments above and after the for loop are removed, it gets an overflow? g.Dispose(); } }

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iPhone multi-touch scale and rotate, how to prevent scale?

- by russhill

I have existing code for tracking multi-touch positions and then rotating and scaling the item - in this case an image - appropriately. The code works really well and in itself is perfect, however for this particular task, I need the rotation ONLY. I have spent time trying to work out what is going on in this routine, but maths is not my strong point so wanted to see if anyone could assist? - (CGAffineTransform)incrementalTransformWithTouches:(NSSet *)touches { NSArray *sortedTouches = [[touches allObjects] sortedArrayUsingSelector:@selector(compareAddress:)]; NSInteger numTouches = [sortedTouches count]; // No touches if (numTouches == 0) { return CGAffineTransformIdentity; } // Single touch if (numTouches == 1) { UITouch *touch = [sortedTouches objectAtIndex:0]; CGPoint beginPoint = *(CGPoint *)CFDictionaryGetValue(touchBeginPoints, touch); CGPoint currentPoint = [touch locationInView:self.superview]; return CGAffineTransformMakeTranslation(currentPoint.x - beginPoint.x, currentPoint.y - beginPoint.y); } // If two or more touches, go with the first two (sorted by address) UITouch *touch1 = [sortedTouches objectAtIndex:0]; UITouch *touch2 = [sortedTouches objectAtIndex:1]; CGPoint beginPoint1 = *(CGPoint *)CFDictionaryGetValue(touchBeginPoints, touch1); CGPoint currentPoint1 = [touch1 locationInView:self.superview]; CGPoint beginPoint2 = *(CGPoint *)CFDictionaryGetValue(touchBeginPoints, touch2); CGPoint currentPoint2 = [touch2 locationInView:self.superview]; double layerX = self.center.x; double layerY = self.center.y; double x1 = beginPoint1.x - layerX; double y1 = beginPoint1.y - layerY; double x2 = beginPoint2.x - layerX; double y2 = beginPoint2.y - layerY; double x3 = currentPoint1.x - layerX; double y3 = currentPoint1.y - layerY; double x4 = currentPoint2.x - layerX; double y4 = currentPoint2.y - layerY; // Solve the system: // [a b t1, -b a t2, 0 0 1] * [x1, y1, 1] = [x3, y3, 1] // [a b t1, -b a t2, 0 0 1] * [x2, y2, 1] = [x4, y4, 1] double D = (y1-y2)*(y1-y2) + (x1-x2)*(x1-x2); if (D < 0.1) { return CGAffineTransformMakeTranslation(x3-x1, y3-y1); } double a = (y1-y2)*(y3-y4) + (x1-x2)*(x3-x4); double b = (y1-y2)*(x3-x4) - (x1-x2)*(y3-y4); double tx = (y1*x2 - x1*y2)*(y4-y3) - (x1*x2 + y1*y2)*(x3+x4) + x3*(y2*y2 + x2*x2) + x4*(y1*y1 + x1*x1); double ty = (x1*x2 + y1*y2)*(-y4-y3) + (y1*x2 - x1*y2)*(x3-x4) + y3*(y2*y2 + x2*x2) + y4*(y1*y1 + x1*x1); return CGAffineTransformMake(a/D, -b/D, b/D, a/D, tx/D, ty/D); } I have tried to read up on the way matrix's work, but cannot figure it out entirely. More likely to be the issue is the calculations, which as I mention is not my strong point. What I need from this routine is a transform that performs my rotation but ignores scale - so the distance between the 2 finger touch points is ignored and scale is not affected. I have looked at other routines on the internet to handle multi-touch rotation but all the ones I tried had issues in some way or other, whereas the above code is spot on for scale and rotate actions. Any help appreciated!

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convert pixels into image

- by Zeta Op

what i am trying to do is to convert a pixel from a video cam, into an image to expalin it better imagine a 3d model so.. the pixels would be each polying, and i want to do is to conver each polyigon into an image. what i have so far is this ** import processing.video.*; PImage hoja; Capture cam; boolean uno, dos, tres, cuatro; import ddf.minim.*; Minim minim; AudioPlayer audio; float set; void setup() { //audio minim = new Minim(this); // audio = minim.loadFile("audio"); // audio.loop(); // uno=false; dos=false; tres=false; cuatro=true; size(640, 480); hoja=loadImage("hoja.gif"); cam = new Capture(this, width, height); cam.start(); } void draw() { if (cam.available() == true) { cam.read(); if (uno==true) { filtroUno(); image(cam, 0, 0, 640, 480); } if (dos==true) { filtroDos(); } if(tres==true){ filtroTres(); } if(cuatro==true){ filtroCuatro(); image(cam, set, 0,640,480); } } // The following does the same, and is faster when just drawing the image // without any additional resizing, transformations, or tint. //set(0, 0, cam); } void filtroUno() { cam.loadPixels(); hoja.loadPixels(); for (int i=0;i<cam.pixels.length;i++) { if (brightness(cam.pixels[i])>110) { cam.pixels[i]=color(0, 255, 255); } else { cam.pixels[i]=color(255, 0, 0); } } for (int i=0;i<cam.width;i+=10) { for (int j=0;j<cam.height;j+=10) { int loc=i+(j*cam.width); if (cam.pixels[loc]==color(255, 0, 0)) { for (int x=i;x<i+10;x++) { for (int y=j;y<j+10;y++) { // println("bla"); int locDos=i+(j*cam.width); cam.pixels[locDos]=hoja.get(x, y); } } } } } cam.updatePixels(); } ** the broblem is that each pixel is creating me a matrix, so.. is not recreating what id that to do. i had the method filtroUno but it wasn't showing ok.. and was the result void filtroUno() { cam.loadPixels(); hoja.loadPixels(); for (int i=0;i<cam.pixels.length;i++) { if (brightness(cam.pixels[i])>110) { cam.pixels[i]=color(0, 255, 255); } else { cam.pixels[i]=color(255, 0, 0); } } for (int i=0;i<cam.width;i+=10) { for (int j=0;j<cam.height;j+=10) { int loc=i+j*hoja.width*10; if (cam.pixels[loc]==color(255, 0, 0)) { for (int x=i;x<i+10;x++) { for (int y=j;y<j+10;y++) { // println("bla"); int locDos=x+y*hoja.height*10; cam.pixels[locDos]=hoja.get(x, y); } } } } } cam.updatePixels(); } i hope you can help me thanks note: each red pixel should be the gif image the imge size is 10x10

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iPhone multi-touch move, scale and rotate, how to prevent scale?

- by russhill

I have existing code for tracking multi-touch positions and then moving, rotating and scaling the item - in this case an image - appropriately. The code works really well and in itself is perfect, however for this particular task, I need the movement and rotation ONLY. I have spent time trying to work out what is going on in this routine, but maths is not my strong point so wanted to see if anyone could assist? - (CGAffineTransform)incrementalTransformWithTouches:(NSSet *)touches { NSArray *sortedTouches = [[touches allObjects] sortedArrayUsingSelector:@selector(compareAddress:)]; NSInteger numTouches = [sortedTouches count]; // No touches if (numTouches == 0) { return CGAffineTransformIdentity; } // Single touch if (numTouches == 1) { UITouch *touch = [sortedTouches objectAtIndex:0]; CGPoint beginPoint = *(CGPoint *)CFDictionaryGetValue(touchBeginPoints, touch); CGPoint currentPoint = [touch locationInView:self.superview]; return CGAffineTransformMakeTranslation(currentPoint.x - beginPoint.x, currentPoint.y - beginPoint.y); } // If two or more touches, go with the first two (sorted by address) UITouch *touch1 = [sortedTouches objectAtIndex:0]; UITouch *touch2 = [sortedTouches objectAtIndex:1]; CGPoint beginPoint1 = *(CGPoint *)CFDictionaryGetValue(touchBeginPoints, touch1); CGPoint currentPoint1 = [touch1 locationInView:self.superview]; CGPoint beginPoint2 = *(CGPoint *)CFDictionaryGetValue(touchBeginPoints, touch2); CGPoint currentPoint2 = [touch2 locationInView:self.superview]; double layerX = self.center.x; double layerY = self.center.y; double x1 = beginPoint1.x - layerX; double y1 = beginPoint1.y - layerY; double x2 = beginPoint2.x - layerX; double y2 = beginPoint2.y - layerY; double x3 = currentPoint1.x - layerX; double y3 = currentPoint1.y - layerY; double x4 = currentPoint2.x - layerX; double y4 = currentPoint2.y - layerY; // Solve the system: // [a b t1, -b a t2, 0 0 1] * [x1, y1, 1] = [x3, y3, 1] // [a b t1, -b a t2, 0 0 1] * [x2, y2, 1] = [x4, y4, 1] double D = (y1-y2)*(y1-y2) + (x1-x2)*(x1-x2); if (D < 0.1) { return CGAffineTransformMakeTranslation(x3-x1, y3-y1); } double a = (y1-y2)*(y3-y4) + (x1-x2)*(x3-x4); double b = (y1-y2)*(x3-x4) - (x1-x2)*(y3-y4); double tx = (y1*x2 - x1*y2)*(y4-y3) - (x1*x2 + y1*y2)*(x3+x4) + x3*(y2*y2 + x2*x2) + x4*(y1*y1 + x1*x1); double ty = (x1*x2 + y1*y2)*(-y4-y3) + (y1*x2 - x1*y2)*(x3-x4) + y3*(y2*y2 + x2*x2) + y4*(y1*y1 + x1*x1); return CGAffineTransformMake(a/D, -b/D, b/D, a/D, tx/D, ty/D); } I have tried to read up on the way matrix's work, but cannot figure it out entirely. More likely to be the issue is the calculations, which as I mention is not my strong point. What I need from this routine is a transform that performs my movement and rotation but ignores scale - so the distance between the 2 finger touch points is ignored and scale is not affected. I have looked at other routines on the internet to handle multi-touch rotation but all the ones I tried had issues in some way or other (smoothness, jumping when lifting fingers etc), whereas the above code is spot on for move, scale and rotate actions. Any help appreciated!

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Reordering Variadic Parameters

- by void-pointer

I have come across the need to reorder a variadic list of parameters that is supplied to the constructor of a struct. After being reordered based on their types, the parameters will be stored as a tuple. My question is how this can be done so that a modern C++ compiler (e.g. g++-4.7) will not generate unnecessary load or store instructions. That is, when the constructor is invoked with a list of parameters of variable size, it efficiently pushes each parameter into place based on an ordering over the parameters' types. Here is a concrete example. Assume that the base type of every parameter (without references, rvalue references, pointers, or qualifiers) is either char, int, or float. How can I make it so that all the parameters of base type char appear first, followed by all of those of base type int (which leaves the parameters of base type float last). The relative order in which the parameters were given should not be violated within sublists of homogeneous base type. Example: foo::foo() is called with arguments float a, char&& b, const float& c, int&& d, char e. The tuple tupe is std::tuple<char, char, int, float, float>, and it is constructed like so: tuple_type{std::move(b), e, std::move(d), a, c}. Consider the struct defined below, and assume that the metafunction deduce_reordered_tuple_type is already implemented. How would you write the constructor so that it works as intended? If you think that the code for deduce_reodered_tuple_type, would be useful to you, I can provide it; it's a little long. template <class... Args> struct foo { // Assume that the metafunction deduce_reordered_tuple_type is defined. typedef typename deduce_reordered_tuple_type<Args...>::type tuple_type; tuple_type t_; foo(Args&&... args) : t_{reorder_and_forward_parameters<Args>(args)...} {} }; Edit 1 The technique I describe above does have applications in mathematical frameworks that make heavy use of expression templates, variadic templates, and metaprogramming in order to perform aggressive inlining. Suppose that you wish to define an operator that takes the product of several expressions, each of which may be passed by reference, reference to const, or rvalue reference. (In my case, the expressions are conditional probability tables and the operation is the factor product, but something like matrix multiplication works suitably as well.) You need access to the data provided by each expression in order to evaluate the product. Consequently, you must move the expressions passed as rvalue references, copy the expressions passed by reference to const, and take the addresses of expressions passed by reference. Using the technique I describe above now poses several benefits. Other expressions can use uniform syntax to access data elements from this expression, since all of the heavy-lifting metaprogramming work is done beforehand, within the class. We can save stack space by grouping the pointers together and storing the larger expressions towards the end of the tuple. Implementing certain types of queries becomes much easier (e.g. check whether any of the pointers stored in the tuple aliases a given pointer). Thank you very much for your help!

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Generate SVG in Javascript

- by Shadowbob

I'm trying to load a SVG with Javascript. I did it quite often with success, but this time it has a strange return. Here is my JS var xmlns = 'http://www.w3.org/2000/svg'; var container = document.getElementById('svgContainer'); var svg = document.createElementNS(xmlns, 'svg'); svg.setAttribute('xmlns', xmlns); svg.setAttribute('version', '1.2'); var defs = document.createElementNS(xmlns, 'defs'); var lg = document.createElementNS(xmlns, 'linearGradient'); lg.setAttribute('id', 'lg'); defs.appendChild(lg); var stop1 = document.createElementNS(xmlns, 'stop'); stop1.setAttribute('offset', '0'); stop1.setAttribute('style', 'stop-color:#ffffff;stop-opacity:1'); lg.appendChild(stop1); var stop2 = document.createElementNS(xmlns, 'stop'); stop2.setAttribute('offset', '1'); stop2.setAttribute('style', 'stop-color:#000000;stop-opacity:1'); lg.appendChild(stop2); var rg = document.createElementNS(xmlns, 'radialGradient'); rg.setAttribute('cx', '171.20810'); rg.setAttribute('cy', '196.85463'); rg.setAttribute('r', '200.00000'); rg.setAttribute('fx', '171.20810'); rg.setAttribute('fy', '196.85463'); rg.setAttribute('id', 'rg'); rg.setAttribute('xlink:href', '#lg'); rg.setAttribute('gradientUnits', 'userSpaceOnUse'); rg.setAttribute('gradientTransform', 'matrix(1.040418,0.796229,-0.814518,1.064316,153.4218,-150.4353)'); defs.appendChild(rg); svg.appendChild(defs); var g = document.createElementNS (xmlns, 'g'); g.setAttribute('transform', 'scale(0.2,0.2)'); svg.appendChild(g); container.appendChild(svg); var path = document.createElementNS (xmlns, 'path'); path.setAttribute('d', 'M 450.00000 255.00000 A 200.00000 205.00000 0 1 1 50.000000,255.00000 A 200.00000 205.00000 0 1 1 450.00000 255.00000 z'); path.setAttribute('style', 'opacity:1.0000000;fill:url(#rg);fill-opacity:1.0000000;fill-rule:evenodd;stroke:none;stroke-width:8.0000000;stroke-linecap:round;stroke-linejoin:round;stroke-miterlimit:4;stroke-dasharray:none;stroke-dashoffset:0;stroke-opacity:1'); g.appendChild(path); So it generates the perfect HTML DOM elements in the proper order, but it doesn't show anything. When I copy the HTML from the source and paste it, it renders the HTML but not the Javascript, but it's the exact same code. You can see the source here. The weird thing is that when I put the radialGradient in the DOM, it works. You can see it in here. So how should I do this? This problem is on all browsers. Thank you for your help.

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Can i use a switch to hold a function?

- by TIMOTHY

I have a 3 file program, basically teaching myself c++. I have an issue. I made a switch to use the math function. I need and put it in a variable, but for some reason I get a zero as a result. Also another issue, when I select 4 (divide) it crashes... Is there a reason? Main file: #include <iostream> #include "math.h" #include <string> using namespace std; int opersel; int c; int a; int b; string test; int main(){ cout << "Welcome to Math-matrix v.34"<< endl; cout << "Shall we begin?" <<endl; //ASK USER IF THEY ARE READY TO BEGIN string answer; cin >> answer; if(answer == "yes" || answer == "YES" || answer == "Yes") { cout << "excellent lets begin..." << endl; cout << "please select a operator..." << endl << endl; cout << "(1) + " << endl; cout << "(2) - " << endl; cout << "(3) * " << endl; cout << "(4) / " << endl; cin >> opersel; switch(opersel){ case 1: c = add(a,b); break; case 2: c = sub(a,b); break; case 3: c = multi(a,b); break; case 4: c = divide(a,b); break; default: cout << "error... retry" << endl; }// end retry cout << "alright, how please select first digit?" << endl; cin >> a; cout << "excellent... and your second?" << endl; cin >> b; cout << c; cin >> test; }else if (answer == "no" || answer == "NO" || answer == "No"){ }//GAME ENDS }// end of int main Here is my math.h file #ifndef MATH_H #define MATH_H int add(int a, int b); int sub(int a, int b); int multi(int a, int b); int divide(int a, int b); #endif Here is my math.cpp: int add(int a, int b) { return a + b; } int sub(int a, int b) { return a - b; } int multi(int a, int b) { return a * b; } int divide(int a, int b) { return a / b; } }// end of int main

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Generating 2-dimensional vla ends in segmentation fault

- by Framester

Hi, further developing the code from yesterday (seg fault caused by malloc and sscanf in a function), I tried with the help of some tutorials I found on the net to generate a 2-dim vla. But I get a segmentation fault at (*data)[i][j]=atof(p);. The program is supposed to read a matrix out of a text file and load it into a 2d array (cols 1-9) and a 1D array (col 10) [Example code] #include<stdio.h> #include<stdlib.h> #include<math.h> #include<string.h> const int LENGTH = 1024; void read_data(float ***data, int **classes, int *nrow,int *ncol, char *filename){ FILE *pfile = NULL; char line[LENGTH]; if(!( pfile=fopen(filename,"r"))){ printf("Error opening %s.", filename); exit(1); } int numlines=0; int numcols=0; char *p; fgets(line,LENGTH,pfile); p = strtok (line," "); while (p != NULL){ p = strtok (NULL, ", "); numcols++; } while(fgets(line,LENGTH,pfile)){ numlines++; } rewind(pfile); int numfeats=numcols-1; *data=(float**) malloc(numlines*sizeof(float*)); *classes=(int *)malloc(numlines*sizeof(int)); if(*classes == NULL){ printf("\nOut of memory."); exit(1); } int i=0; while(fgets(line,LENGTH,pfile)){ p = strtok (line," "); for(int j=0;j<numfeats;j++) { (data)[i]=malloc(numfeats*sizeof(float)); printf("%i ",i); (*data)[i][j]=atof(p); p = strtok (NULL, ", "); } (*classes)[i]=atoi(p); i++; } fclose(pfile); *nrow=numlines; *ncol=numfeats; } int main() { char *filename="somedatafile.txt"; float **data2; int *classes2; int r,c; read_data(&data2,&classes2, &r, &c,filename) ; for(int i=0;i<r;i++){ printf("\n"); for(int j=0;j<c;j++){ printf("%f",data2[i][j]); } } return 1; } [Content of somedatafile.txt] 50 21 77 0 28 0 27 48 22 2 55 0 92 0 0 26 36 92 56 4 53 0 82 0 52 -5 29 30 2 1 37 0 76 0 28 18 40 48 8 1 37 0 79 0 34 -26 43 46 2 1 85 0 88 -4 6 1 3 83 80 5 56 0 81 0 -4 11 25 86 62 4 55 -1 95 -3 54 -4 40 41 2 1 53 8 77 0 28 0 23 48 24 4 37 0 101 -7 28 0 64 73 8 1 ...

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R concentrating data frame

- by user1631503

I have a data frame like this >X_com Day_1 Day_2 Day_3 Day_4 Day_5 Day_6 Day_7 Day_8 Day_9 Day_10 1 0 0 0 0 0 0 0 0 0 1 2 0 0 0 0 0 0 0 0 0 0 3 0 0 0 0 0 0 0 0 0 0 4 0 0 0 0 0 0 0 0 0 0 5 0 0 0 0 0 0 0 0 0 0 6 0 0 0 0 0 0 0 0 0 0 7 0 0 0 0 0 0 0 0 0 0 8 0 0 0 0 0 0 0 0 0 0 I need to concentrate all the values into one column and add another column with "1;" So I did this > X_new=matrix(1,8,2) > X_new[1,]=paste(X_com[1,1], X_com[1,2],X_com[1,3],X_com [1,4],X_com[1,5],X_com[1,6],X_com[1,7],X_com[1,8],X_com [1,9],X_com[1,10], sep="") > X_new[2,]=paste(X_com[2,1], X_com[2,2],X_com[2,3],X_com [2,4],X_com[2,5],X_com[2,6],X_com[2,7],X_com[2,8],X_com [2,9],X_com[2,10], sep="") > X_new[3,]=paste(X_com[3,1], X_com[3,2],X_com[3,3],X_com [3,4],X_com[3,5],X_com[3,6],X_com[3,7],X_com[3,8],X_com [3,9],X_com[3,10], sep="") > X_new[4,]=paste(X_com[4,1], X_com[4,2],X_com[4,3],X_com [4,4],X_com[4,5],X_com[4,6],X_com[4,7],X_com[4,8],X_com [4,9],X_com[4,10], sep="") > X_new[5,]=paste(X_com[5,1], X_com[5,2],X_com[5,3],X_com [5,4],X_com[5,5],X_com[5,6],X_com[5,7],X_com[5,8],X_com [5,9],X_com[5,10], sep="") > X_new[6,]=paste(X_com[6,1], X_com[6,2],X_com[6,3],X_com [6,4],X_com[6,5],X_com[6,6],X_com[6,7],X_com[6,8],X_com [6,9],X_com[6,10], sep="") > X_new[7,]=paste(X_com[7,1], X_com[7,2],X_com[7,3],X_com [7,4],X_com[7,5],X_com[7,6],X_com[7,7],X_com[7,8],X_com [7,9],X_com[7,10], sep="") > X_new[8,]=paste(X_com[8,1], X_com[8,2],X_com[8,3],X_com [8,4],X_com[8,5],X_com[8,6],X_com[8,7],X_com[8,8],X_com [8,9],X_com[8,10], sep="") > X_new[1:8,2]="1;" > as.data.frame(X_new) V1 V2 1 0000000001 1; 2 0000000000 1; 3 0000000000 1; 4 0000000000 1; 5 0000000000 1; 6 0000000000 1; 7 0000000000 1; 8 0000000000 1; I believe there's definitely a faster way of achieving this but have no clue. The other problem is, I have over a thousand of data frame like this needs to be concentrated. I'm still learning how to loop these repetitive steps but is progressing quite slowly. If the original data frames were named uniquely, does that mean I have no choice but to work on each of them individually? Thank you in advance.

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How LINQ to Object statements work

- by rajbk

This post goes into detail as to now LINQ statements work when querying a collection of objects. This topic assumes you have an understanding of how generics, delegates, implicitly typed variables, lambda expressions, object/collection initializers, extension methods and the yield statement work. I would also recommend you read my previous two posts: Using Delegates in C# Part 1 Using Delegates in C# Part 2 We will start by writing some methods to filter a collection of data. Assume we have an Employee class like so: 1: public class Employee { 2: public int ID { get; set;} 3: public string FirstName { get; set;} 4: public string LastName {get; set;} 5: public string Country { get; set; } 6: } and a collection of employees like so: 1: var employees = new List<Employee> { 2: new Employee { ID = 1, FirstName = "John", LastName = "Wright", Country = "USA" }, 3: new Employee { ID = 2, FirstName = "Jim", LastName = "Ashlock", Country = "UK" }, 4: new Employee { ID = 3, FirstName = "Jane", LastName = "Jackson", Country = "CHE" }, 5: new Employee { ID = 4, FirstName = "Jill", LastName = "Anderson", Country = "AUS" }, 6: }; Filtering We wish to find all employees that have an even ID. We could start off by writing a method that takes in a list of employees and returns a filtered list of employees with an even ID. 1: static List<Employee> GetEmployeesWithEvenID(List<Employee> employees) { 2: var filteredEmployees = new List<Employee>(); 3: foreach (Employee emp in employees) { 4: if (emp.ID % 2 == 0) { 5: filteredEmployees.Add(emp); 6: } 7: } 8: return filteredEmployees; 9: } The method can be rewritten to return an IEnumerable<Employee> using the yield return keyword. 1: static IEnumerable<Employee> GetEmployeesWithEvenID(IEnumerable<Employee> employees) { 2: foreach (Employee emp in employees) { 3: if (emp.ID % 2 == 0) { 4: yield return emp; 5: } 6: } 7: } We put these together in a console application. 1: using System; 2: using System.Collections.Generic; 3: //No System.Linq 4: 5: public class Program 6: { 7: [STAThread] 8: static void Main(string[] args) 9: { 10: var employees = new List<Employee> { 11: new Employee { ID = 1, FirstName = "John", LastName = "Wright", Country = "USA" }, 12: new Employee { ID = 2, FirstName = "Jim", LastName = "Ashlock", Country = "UK" }, 13: new Employee { ID = 3, FirstName = "Jane", LastName = "Jackson", Country = "CHE" }, 14: new Employee { ID = 4, FirstName = "Jill", LastName = "Anderson", Country = "AUS" }, 15: }; 16: var filteredEmployees = GetEmployeesWithEvenID(employees); 17: 18: foreach (Employee emp in filteredEmployees) { 19: Console.WriteLine("ID {0} First_Name {1} Last_Name {2} Country {3}", 20: emp.ID, emp.FirstName, emp.LastName, emp.Country); 21: } 22: 23: Console.ReadLine(); 24: } 25: 26: static IEnumerable<Employee> GetEmployeesWithEvenID(IEnumerable<Employee> employees) { 27: foreach (Employee emp in employees) { 28: if (emp.ID % 2 == 0) { 29: yield return emp; 30: } 31: } 32: } 33: } 34: 35: public class Employee { 36: public int ID { get; set;} 37: public string FirstName { get; set;} 38: public string LastName {get; set;} 39: public string Country { get; set; } 40: } Output: ID 2 First_Name Jim Last_Name Ashlock Country UK ID 4 First_Name Jill Last_Name Anderson Country AUS Our filtering method is too specific. Let us change it so that it is capable of doing different types of filtering and lets give our method the name Where ;-) We will add another parameter to our Where method. This additional parameter will be a delegate with the following declaration. public delegate bool Filter(Employee emp); The idea is that the delegate parameter in our Where method will point to a method that contains the logic to do our filtering thereby freeing our Where method from any dependency. The method is shown below: 1: static IEnumerable<Employee> Where(IEnumerable<Employee> employees, Filter filter) { 2: foreach (Employee emp in employees) { 3: if (filter(emp)) { 4: yield return emp; 5: } 6: } 7: } Making the change to our app, we create a new instance of the Filter delegate on line 14 with a target set to the method EmployeeHasEvenId. Running the code will produce the same output. 1: public delegate bool Filter(Employee emp); 2: 3: public class Program 4: { 5: [STAThread] 6: static void Main(string[] args) 7: { 8: var employees = new List<Employee> { 9: new Employee { ID = 1, FirstName = "John", LastName = "Wright", Country = "USA" }, 10: new Employee { ID = 2, FirstName = "Jim", LastName = "Ashlock", Country = "UK" }, 11: new Employee { ID = 3, FirstName = "Jane", LastName = "Jackson", Country = "CHE" }, 12: new Employee { ID = 4, FirstName = "Jill", LastName = "Anderson", Country = "AUS" } 13: }; 14: var filterDelegate = new Filter(EmployeeHasEvenId); 15: var filteredEmployees = Where(employees, filterDelegate); 16: 17: foreach (Employee emp in filteredEmployees) { 18: Console.WriteLine("ID {0} First_Name {1} Last_Name {2} Country {3}", 19: emp.ID, emp.FirstName, emp.LastName, emp.Country); 20: } 21: Console.ReadLine(); 22: } 23: 24: static bool EmployeeHasEvenId(Employee emp) { 25: return emp.ID % 2 == 0; 26: } 27: 28: static IEnumerable<Employee> Where(IEnumerable<Employee> employees, Filter filter) { 29: foreach (Employee emp in employees) { 30: if (filter(emp)) { 31: yield return emp; 32: } 33: } 34: } 35: } 36: 37: public class Employee { 38: public int ID { get; set;} 39: public string FirstName { get; set;} 40: public string LastName {get; set;} 41: public string Country { get; set; } 42: } Lets use lambda expressions to inline the contents of the EmployeeHasEvenId method in place of the method. The next code snippet shows this change (see line 15). For brevity, the Employee class declaration has been skipped. 1: public delegate bool Filter(Employee emp); 2: 3: public class Program 4: { 5: [STAThread] 6: static void Main(string[] args) 7: { 8: var employees = new List<Employee> { 9: new Employee { ID = 1, FirstName = "John", LastName = "Wright", Country = "USA" }, 10: new Employee { ID = 2, FirstName = "Jim", LastName = "Ashlock", Country = "UK" }, 11: new Employee { ID = 3, FirstName = "Jane", LastName = "Jackson", Country = "CHE" }, 12: new Employee { ID = 4, FirstName = "Jill", LastName = "Anderson", Country = "AUS" } 13: }; 14: var filterDelegate = new Filter(EmployeeHasEvenId); 15: var filteredEmployees = Where(employees, emp => emp.ID % 2 == 0); 16: 17: foreach (Employee emp in filteredEmployees) { 18: Console.WriteLine("ID {0} First_Name {1} Last_Name {2} Country {3}", 19: emp.ID, emp.FirstName, emp.LastName, emp.Country); 20: } 21: Console.ReadLine(); 22: } 23: 24: static bool EmployeeHasEvenId(Employee emp) { 25: return emp.ID % 2 == 0; 26: } 27: 28: static IEnumerable<Employee> Where(IEnumerable<Employee> employees, Filter filter) { 29: foreach (Employee emp in employees) { 30: if (filter(emp)) { 31: yield return emp; 32: } 33: } 34: } 35: } 36: The output displays the same two employees. Our Where method is too restricted since it works with a collection of Employees only. Lets change it so that it works with any IEnumerable<T>. In addition, you may recall from my previous post, that .NET 3.5 comes with a lot of predefined delegates including public delegate TResult Func<T, TResult>(T arg); We will get rid of our Filter delegate and use the one above instead. We apply these two changes to our code. 1: public class Program 2: { 3: [STAThread] 4: static void Main(string[] args) 5: { 6: var employees = new List<Employee> { 7: new Employee { ID = 1, FirstName = "John", LastName = "Wright", Country = "USA" }, 8: new Employee { ID = 2, FirstName = "Jim", LastName = "Ashlock", Country = "UK" }, 9: new Employee { ID = 3, FirstName = "Jane", LastName = "Jackson", Country = "CHE" }, 10: new Employee { ID = 4, FirstName = "Jill", LastName = "Anderson", Country = "AUS" } 11: }; 12: 13: var filteredEmployees = Where(employees, emp => emp.ID % 2 == 0); 14: 15: foreach (Employee emp in filteredEmployees) { 16: Console.WriteLine("ID {0} First_Name {1} Last_Name {2} Country {3}", 17: emp.ID, emp.FirstName, emp.LastName, emp.Country); 18: } 19: Console.ReadLine(); 20: } 21: 22: static IEnumerable<T> Where<T>(IEnumerable<T> source, Func<T, bool> filter) { 23: foreach (var x in source) { 24: if (filter(x)) { 25: yield return x; 26: } 27: } 28: } 29: } We have successfully implemented a way to filter any IEnumerable<T> based on a filter criteria. Projection Now lets enumerate on the items in the IEnumerable<Employee> we got from the Where method and copy them into a new IEnumerable<EmployeeFormatted>. The EmployeeFormatted class will only have a FullName and ID property. 1: public class EmployeeFormatted { 2: public int ID { get; set; } 3: public string FullName {get; set;} 4: } We could “project” our existing IEnumerable<Employee> into a new collection of IEnumerable<EmployeeFormatted> with the help of a new method. We will call this method Select ;-) 1: static IEnumerable<EmployeeFormatted> Select(IEnumerable<Employee> employees) { 2: foreach (var emp in employees) { 3: yield return new EmployeeFormatted { 4: ID = emp.ID, 5: FullName = emp.LastName + ", " + emp.FirstName 6: }; 7: } 8: } The changes are applied to our app. 1: public class Program 2: { 3: [STAThread] 4: static void Main(string[] args) 5: { 6: var employees = new List<Employee> { 7: new Employee { ID = 1, FirstName = "John", LastName = "Wright", Country = "USA" }, 8: new Employee { ID = 2, FirstName = "Jim", LastName = "Ashlock", Country = "UK" }, 9: new Employee { ID = 3, FirstName = "Jane", LastName = "Jackson", Country = "CHE" }, 10: new Employee { ID = 4, FirstName = "Jill", LastName = "Anderson", Country = "AUS" } 11: }; 12: 13: var filteredEmployees = Where(employees, emp => emp.ID % 2 == 0); 14: var formattedEmployees = Select(filteredEmployees); 15: 16: foreach (EmployeeFormatted emp in formattedEmployees) { 17: Console.WriteLine("ID {0} Full_Name {1}", 18: emp.ID, emp.FullName); 19: } 20: Console.ReadLine(); 21: } 22: 23: static IEnumerable<T> Where<T>(IEnumerable<T> source, Func<T, bool> filter) { 24: foreach (var x in source) { 25: if (filter(x)) { 26: yield return x; 27: } 28: } 29: } 30: 31: static IEnumerable<EmployeeFormatted> Select(IEnumerable<Employee> employees) { 32: foreach (var emp in employees) { 33: yield return new EmployeeFormatted { 34: ID = emp.ID, 35: FullName = emp.LastName + ", " + emp.FirstName 36: }; 37: } 38: } 39: } 40: 41: public class Employee { 42: public int ID { get; set;} 43: public string FirstName { get; set;} 44: public string LastName {get; set;} 45: public string Country { get; set; } 46: } 47: 48: public class EmployeeFormatted { 49: public int ID { get; set; } 50: public string FullName {get; set;} 51: } Output: ID 2 Full_Name Ashlock, Jim ID 4 Full_Name Anderson, Jill We have successfully selected employees who have an even ID and then shaped our data with the help of the Select method so that the final result is an IEnumerable<EmployeeFormatted>. Lets make our Select method more generic so that the user is given the freedom to shape what the output would look like. We can do this, like before, with lambda expressions. Our Select method is changed to accept a delegate as shown below. TSource will be the type of data that comes in and TResult will be the type the user chooses (shape of data) as returned from the selector delegate. 1: 2: static IEnumerable<TResult> Select<TSource, TResult>(IEnumerable<TSource> source, Func<TSource, TResult> selector) { 3: foreach (var x in source) { 4: yield return selector(x); 5: } 6: } We see the new changes to our app. On line 15, we use lambda expression to specify the shape of the data. In this case the shape will be of type EmployeeFormatted. 1: 2: public class Program 3: { 4: [STAThread] 5: static void Main(string[] args) 6: { 7: var employees = new List<Employee> { 8: new Employee { ID = 1, FirstName = "John", LastName = "Wright", Country = "USA" }, 9: new Employee { ID = 2, FirstName = "Jim", LastName = "Ashlock", Country = "UK" }, 10: new Employee { ID = 3, FirstName = "Jane", LastName = "Jackson", Country = "CHE" }, 11: new Employee { ID = 4, FirstName = "Jill", LastName = "Anderson", Country = "AUS" } 12: }; 13: 14: var filteredEmployees = Where(employees, emp => emp.ID % 2 == 0); 15: var formattedEmployees = Select(filteredEmployees, (emp) => 16: new EmployeeFormatted { 17: ID = emp.ID, 18: FullName = emp.LastName + ", " + emp.FirstName 19: }); 20: 21: foreach (EmployeeFormatted emp in formattedEmployees) { 22: Console.WriteLine("ID {0} Full_Name {1}", 23: emp.ID, emp.FullName); 24: } 25: Console.ReadLine(); 26: } 27: 28: static IEnumerable<T> Where<T>(IEnumerable<T> source, Func<T, bool> filter) { 29: foreach (var x in source) { 30: if (filter(x)) { 31: yield return x; 32: } 33: } 34: } 35: 36: static IEnumerable<TResult> Select<TSource, TResult>(IEnumerable<TSource> source, Func<TSource, TResult> selector) { 37: foreach (var x in source) { 38: yield return selector(x); 39: } 40: } 41: } The code outputs the same result as before. On line 14 we filter our data and on line 15 we project our data. What if we wanted to be more expressive and concise? We could combine both line 14 and 15 into one line as shown below. Assuming you had to perform several operations like this on our collection, you would end up with some very unreadable code! 1: var formattedEmployees = Select(Where(employees, emp => emp.ID % 2 == 0), (emp) => 2: new EmployeeFormatted { 3: ID = emp.ID, 4: FullName = emp.LastName + ", " + emp.FirstName 5: }); A cleaner way to write this would be to give the appearance that the Select and Where methods were part of the IEnumerable<T>. This is exactly what extension methods give us. Extension methods have to be defined in a static class. Let us make the Select and Where extension methods on IEnumerable<T> 1: public static class MyExtensionMethods { 2: static IEnumerable<T> Where<T>(this IEnumerable<T> source, Func<T, bool> filter) { 3: foreach (var x in source) { 4: if (filter(x)) { 5: yield return x; 6: } 7: } 8: } 9: 10: static IEnumerable<TResult> Select<TSource, TResult>(this IEnumerable<TSource> source, Func<TSource, TResult> selector) { 11: foreach (var x in source) { 12: yield return selector(x); 13: } 14: } 15: } The creation of the extension method makes the syntax much cleaner as shown below. We can write as many extension methods as we want and keep on chaining them using this technique. 1: var formattedEmployees = employees 2: .Where(emp => emp.ID % 2 == 0) 3: .Select (emp => new EmployeeFormatted { ID = emp.ID, FullName = emp.LastName + ", " + emp.FirstName }); Making these changes and running our code produces the same result. 1: using System; 2: using System.Collections.Generic; 3: 4: public class Program 5: { 6: [STAThread] 7: static void Main(string[] args) 8: { 9: var employees = new List<Employee> { 10: new Employee { ID = 1, FirstName = "John", LastName = "Wright", Country = "USA" }, 11: new Employee { ID = 2, FirstName = "Jim", LastName = "Ashlock", Country = "UK" }, 12: new Employee { ID = 3, FirstName = "Jane", LastName = "Jackson", Country = "CHE" }, 13: new Employee { ID = 4, FirstName = "Jill", LastName = "Anderson", Country = "AUS" } 14: }; 15: 16: var formattedEmployees = employees 17: .Where(emp => emp.ID % 2 == 0) 18: .Select (emp => 19: new EmployeeFormatted { 20: ID = emp.ID, 21: FullName = emp.LastName + ", " + emp.FirstName 22: } 23: ); 24: 25: foreach (EmployeeFormatted emp in formattedEmployees) { 26: Console.WriteLine("ID {0} Full_Name {1}", 27: emp.ID, emp.FullName); 28: } 29: Console.ReadLine(); 30: } 31: } 32: 33: public static class MyExtensionMethods { 34: static IEnumerable<T> Where<T>(this IEnumerable<T> source, Func<T, bool> filter) { 35: foreach (var x in source) { 36: if (filter(x)) { 37: yield return x; 38: } 39: } 40: } 41: 42: static IEnumerable<TResult> Select<TSource, TResult>(this IEnumerable<TSource> source, Func<TSource, TResult> selector) { 43: foreach (var x in source) { 44: yield return selector(x); 45: } 46: } 47: } 48: 49: public class Employee { 50: public int ID { get; set;} 51: public string FirstName { get; set;} 52: public string LastName {get; set;} 53: public string Country { get; set; } 54: } 55: 56: public class EmployeeFormatted { 57: public int ID { get; set; } 58: public string FullName {get; set;} 59: } Let’s change our code to return a collection of anonymous types and get rid of the EmployeeFormatted type. We see that the code produces the same output. 1: using System; 2: using System.Collections.Generic; 3: 4: public class Program 5: { 6: [STAThread] 7: static void Main(string[] args) 8: { 9: var employees = new List<Employee> { 10: new Employee { ID = 1, FirstName = "John", LastName = "Wright", Country = "USA" }, 11: new Employee { ID = 2, FirstName = "Jim", LastName = "Ashlock", Country = "UK" }, 12: new Employee { ID = 3, FirstName = "Jane", LastName = "Jackson", Country = "CHE" }, 13: new Employee { ID = 4, FirstName = "Jill", LastName = "Anderson", Country = "AUS" } 14: }; 15: 16: var formattedEmployees = employees 17: .Where(emp => emp.ID % 2 == 0) 18: .Select (emp => 19: new { 20: ID = emp.ID, 21: FullName = emp.LastName + ", " + emp.FirstName 22: } 23: ); 24: 25: foreach (var emp in formattedEmployees) { 26: Console.WriteLine("ID {0} Full_Name {1}", 27: emp.ID, emp.FullName); 28: } 29: Console.ReadLine(); 30: } 31: } 32: 33: public static class MyExtensionMethods { 34: public static IEnumerable<T> Where<T>(this IEnumerable<T> source, Func<T, bool> filter) { 35: foreach (var x in source) { 36: if (filter(x)) { 37: yield return x; 38: } 39: } 40: } 41: 42: public static IEnumerable<TResult> Select<TSource, TResult>(this IEnumerable<TSource> source, Func<TSource, TResult> selector) { 43: foreach (var x in source) { 44: yield return selector(x); 45: } 46: } 47: } 48: 49: public class Employee { 50: public int ID { get; set;} 51: public string FirstName { get; set;} 52: public string LastName {get; set;} 53: public string Country { get; set; } 54: } To be more expressive, C# allows us to write our extension method calls as a query expression. Line 16 can be rewritten a query expression like so: 1: var formattedEmployees = from emp in employees 2: where emp.ID % 2 == 0 3: select new { 4: ID = emp.ID, 5: FullName = emp.LastName + ", " + emp.FirstName 6: }; When the compiler encounters an expression like the above, it simply rewrites it as calls to our extension methods. So far we have been using our extension methods. The System.Linq namespace contains several extension methods for objects that implement the IEnumerable<T>. You can see a listing of these methods in the Enumerable class in the System.Linq namespace. Let’s get rid of our extension methods (which I purposefully wrote to be of the same signature as the ones in the Enumerable class) and use the ones provided in the Enumerable class. Our final code is shown below: 1: using System; 2: using System.Collections.Generic; 3: using System.Linq; //Added 4: 5: public class Program 6: { 7: [STAThread] 8: static void Main(string[] args) 9: { 10: var employees = new List<Employee> { 11: new Employee { ID = 1, FirstName = "John", LastName = "Wright", Country = "USA" }, 12: new Employee { ID = 2, FirstName = "Jim", LastName = "Ashlock", Country = "UK" }, 13: new Employee { ID = 3, FirstName = "Jane", LastName = "Jackson", Country = "CHE" }, 14: new Employee { ID = 4, FirstName = "Jill", LastName = "Anderson", Country = "AUS" } 15: }; 16: 17: var formattedEmployees = from emp in employees 18: where emp.ID % 2 == 0 19: select new { 20: ID = emp.ID, 21: FullName = emp.LastName + ", " + emp.FirstName 22: }; 23: 24: foreach (var emp in formattedEmployees) { 25: Console.WriteLine("ID {0} Full_Name {1}", 26: emp.ID, emp.FullName); 27: } 28: Console.ReadLine(); 29: } 30: } 31: 32: public class Employee { 33: public int ID { get; set;} 34: public string FirstName { get; set;} 35: public string LastName {get; set;} 36: public string Country { get; set; } 37: } 38: 39: public class EmployeeFormatted { 40: public int ID { get; set; } 41: public string FullName {get; set;} 42: } This post has shown you a basic overview of LINQ to Objects work by showning you how an expression is converted to a sequence of calls to extension methods when working directly with objects. It gets more interesting when working with LINQ to SQL where an expression tree is constructed – an in memory data representation of the expression. The C# compiler compiles these expressions into code that builds an expression tree at runtime. The provider can then traverse the expression tree and generate the appropriate SQL query. You can read more about expression trees in this MSDN article.

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