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• What Is The Formula for the 3 of 9 Bar Code Alphabet?

  - by Chris Moschini

  Background: 3 of 9 Barcode Alphabet A simple syntax for 3 of 9 bar codes What is the formula behind the alphabet and digits in a 3 of 9 bar code? For example, ASCII has a relatively clear arrangement. Numbers start at 33, capitals at 65, lowercase at 97. From these starting points you can infer the ASCII code for any number or letter. The start point for each range is also a multiple of 32 + 1. Bar codes seem random and lacking sequence. If we use the syntax from the second link, this is the first six characters in 3 of 9: A 100-01 B 010-01 C 110-00 D 001-01 E 101-00 F 011-00 I see no pattern here; what is it? I'm as much interested in the designer's intended pattern behind these as I am in someone devising an algorithm of their own that can give you the above code for a given character based on its sequence. I struggled with where to put this question; is it history, computer science, information science? I chose Programmers because a StackExchange search had the most barcode hits here, and because I wanted to specifically relate it to ASCII to explain what sort of formula/explanation I'm looking for.

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• Microeconomical simulation: coordination/planning between self-interested trading agents

  - by Milton Manfried

  In a typical perfect-information strategy game like Chess, an agent can calculate its best move by searching the state tree for the best possible move, while assuming that the opponent will also make the best possible move (i.e. Mini-max). I would like to use this approach in a "game" modeling economic activity, where the possible "moves" would be to buy or sell for a given price, and the goal, rather than a specific class of states (e.g. Checkmate), would be to maximize some function F of the agent's state (e.g. F(money, widget) = 10*money + widget). How to handle buy/sell actions that require coordination between both parties, at the very least agreement upon a price? The cheap way out would be to set the price beforehand, maybe based upon the current supply -- but the idea of this simulation is to examine how prices emerge when freely determined by "perfectly rational" agents. A great example of what I do not want is the trading algorithm in SugarScape -- paraphrasing from Growing Artificial Societies p101-102: when a pair of agents interact to trade, they each compute their internal valuations of the goods, then a bargaining process is conducted and a price is agreed to. If this price makes both agents better off, they complete the transaction The protocol itself is beautiful, but what it cannot capture (as far as I can tell) is the ability for an agent to pay more than it might otherwise for a good, because it knows that it can sell it for even more at a later date -- what appears to be called "strategic thinking" in this pape at Google Books Multi-Agent-Based Simulation III: 4th International Workshop, MABS 2003... to get realistic behavior like that, it seems one would either (1) have to build an outrageously-complex internal valuation system which could at best only cover situations that were planned for at compile-time, or otherwise (2) have some mechanism to search the state tree... which would require some way of planning future trades. Note: The chess analogy only works as far as the state-space search goes; the simulation isn't intended to be "zero sum", so a literal mini-max search wouldn't be appropriate -- and ideally, it should work with more than two agents.

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• Proper updating of GeoClipMaps

  - by thr

  I have been working on an implementation of gpu-based geo clip maps, but there is a section of the GPU Gems 2 article that i just can't seem to understand, specifically this paragraph and more precisely the bolded part: The choice of grid size n = 2k-1 has the further advantage that the finer level is never exactly centered with respect to its parent next-coarser level. In other words, it is always offset by 1 grid unit either left or right, as well as either top or bottom (see Figure 2-4), depending on the position of the viewpoint. In fact, it is necessary to allow a finer level to shift while its next-coarser level stays fixed, and therefore the finer level must sometimes be off-center with respect to the next-coarser level. An alternative choice of grid size, such as n = 2k-3, would provide the possibility for exact centering Let's take an example image from the article: My "understanding" of the way the clip maps were update was that you floor the position of the viewpoint to an int, and such get the center vertex point if this is not the same as the previous center point, you update the entire map. Now, this obviously is not the case - but what I am failing to understand is this: If you look at the image above, if the viewpoint was to move one unit to the right, then the inner ring (the one just around the view point + white center square) would end up getting a 1 unit space on both the left and right side of itself. But there is nothing in the paper that deals with this, what i mean is that it would end up looking like this (excuse my crummy cut-and-paste editing of the above image): This is obviously not a valid state of the. So, would the solution be that a clip ring (layer) can only move in increments of the ring/layer it's contained within? Wouldn't this end up being very restrictive? I feel like I am missing some crucial understanding of parts of the algorithm, but I have been over both this paper and the original paper from 2004 and I just can't see what I am not getting.

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• Trouble with SAT style vector projection in C#/XNA

  - by ssb

  Simply put I'm having a hard time working out how to work with XNA's Vector2 types while maintaining spatial considerations. I'm working with separating axis theorem and trying to project vectors onto an arbitrary axis to check if those projections overlap, but the severe lack of XNA-specific help online combined with pseudo code everywhere that omits key parts of the algorithm, googling has left me little help. I'm aware of HOW to project a vector, but the way that I know of doing it involves the two vectors starting from the same point. Particularly here: http://www.metanetsoftware.com/technique/tutorialA.html So let's say I have a simple rectangle, and I store each of its corners in a list of Vector2s. How would I go about projecting that onto an arbitrary axis? The crux of my problem is that taking the dot product of say, a vector2 of (1, 0) and a vector2 of (50, 50) won't get me the dot product I'm looking for.. or will it? Because that (50, 50) won't be the vector of the polygon's vertex but from whatever XNA calculates. It's getting the calculation from the right starting point that's throwing me off. I'm sorry if this is unclear, but my brain is fried from trying to think about this. I need a better understanding of how XNA calculates Vector2s as actual vectors and not just as random points.

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• How to improve Minecraft-esque voxel world performance?

  - by SomeXnaChump

  After playing Minecraft I marveled a bit at its large worlds but at the same time I found them extremely slow to navigate, even with a quad core and meaty graphics card. Now I assume Minecraft is fairly slow because: A) It's written in Java, and as most of the spatial partitioning and memory management activities happen in there, it would naturally be slower than a native C++ version. B) It doesn't partition its world very well. I could be wrong on both assumptions; however it got me thinking about the best way to manage large voxel worlds. As it is a true 3D world, where a block can exist in any part of the world, it is basically a big 3D array [x][y][z], where each block in the world has a type (i.e BlockType.Empty = 0, BlockType.Dirt = 1 etc.) Now, I am assuming to make this sort of world perform well you would need to: A) Use a tree of some variety (oct/kd/bsp) to split all the cubes out; it seems like an oct/kd would be the better option as you can just partition on a per cube level not a per triangle level. B) Use some algorithm to work out which blocks can currently be seen, as blocks closer to the user could obfuscate the blocks behind, making it pointless to render them. C) Keep the block object themselves lightweight, so it is quick to add and remove them from the trees. I guess there is no right answer to this, but I would be interested to see peoples' opinions on the subject. How would you improve performance in a large voxel-based world?

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• How often is your "Go-To" language the same as your favorite??

  - by K-RAN

  I know that there's already a question asking for your favorite programming language here. I'm curious though, what's your go-to language? The two can be very different. For example, I love Haskell. I learned it this past semester and I fell in love with it's very concise solutions and awesome syntax (I love theoretical math so something like fib = 1 : 1 : [ f | f <- zipWith (+) fibSeq (tail fibSeq)] makes my inner mathematician and computer scientist jump with joy!). However, the majority of my projects for classes and jobs have been in C/C++ & Java. As a result, most of the time when I'm testing something like an algorithm or Data Structure I go straight to C++. What about you guys? What languages do you love and why? What about your go-to language? What language do you use most often to get things done for work or personal projects and why? How often does a language fall into both categories??

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• Top 25 security issues for developers of web sites

  - by BizTalk Visionary

  Sourced from: CWE This is a brief listing of the Top 25 items, using the general ranking. NOTE: 16 other weaknesses were considered for inclusion in the Top 25, but their general scores were not high enough. They are listed in the On the Cusp focus profile. Rank Score ID Name [1] 346 CWE-79 Failure to Preserve Web Page Structure ('Cross-site Scripting') [2] 330 CWE-89 Improper Sanitization of Special Elements used in an SQL Command ('SQL Injection') [3] 273 CWE-120 Buffer Copy without Checking Size of Input ('Classic Buffer Overflow') [4] 261 CWE-352 Cross-Site Request Forgery (CSRF) [5] 219 CWE-285 Improper Access Control (Authorization) [6] 202 CWE-807 Reliance on Untrusted Inputs in a Security Decision [7] 197 CWE-22 Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal') [8] 194 CWE-434 Unrestricted Upload of File with Dangerous Type [9] 188 CWE-78 Improper Sanitization of Special Elements used in an OS Command ('OS Command Injection') [10] 188 CWE-311 Missing Encryption of Sensitive Data [11] 176 CWE-798 Use of Hard-coded Credentials [12] 158 CWE-805 Buffer Access with Incorrect Length Value [13] 157 CWE-98 Improper Control of Filename for Include/Require Statement in PHP Program ('PHP File Inclusion') [14] 156 CWE-129 Improper Validation of Array Index [15] 155 CWE-754 Improper Check for Unusual or Exceptional Conditions [16] 154 CWE-209 Information Exposure Through an Error Message [17] 154 CWE-190 Integer Overflow or Wraparound [18] 153 CWE-131 Incorrect Calculation of Buffer Size [19] 147 CWE-306 Missing Authentication for Critical Function [20] 146 CWE-494 Download of Code Without Integrity Check [21] 145 CWE-732 Incorrect Permission Assignment for Critical Resource [22] 145 CWE-770 Allocation of Resources Without Limits or Throttling [23] 142 CWE-601 URL Redirection to Untrusted Site ('Open Redirect') [24] 141 CWE-327 Use of a Broken or Risky Cryptographic Algorithm [25] 138 CWE-362 Race Condition Cross-site scripting and SQL injection are the 1-2 punch of security weaknesses in 2010. Even when a software package doesn't primarily run on the web, there's a good chance that it has a web-based management interface or HTML-based output formats that allow cross-site scripting. For data-rich software applications, SQL injection is the means to steal the keys to the kingdom. The classic buffer overflow comes in third, while more complex buffer overflow variants are sprinkled in the rest of the Top 25.

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• CodePlex Daily Summary for Tuesday, June 10, 2014

  CodePlex Daily Summary for Tuesday, June 10, 2014Popular ReleasesBell Open Imaging package: 1.0: First release at Codeplex.Australia Income and Tax Calculator: Australia Income and Tax Calculator 1.4: 1. added 2014 financial year 2. refactored the codeCS-Script Source: Release v3.8.1: Improved ConfigConsole AdvancedShell extensions support cs-script.7z - CS-Script Suite (binaries, documentation, samples) cs-script.ExtensionPack.7z - CS-Script Extension Pack (additional binaries and samples) cs-scriptDocs.7z - CS-Script DocumentationPapercut: Papercut v3.0.0.0: Papercut has switched to semantic versioning! That means you will have to uninstall old "clickonce" versions to get the latest as it will see it as an older version. Latest Has Tons of New Features: Modern UI MVVM Architecture Watch Directories for New Messages Optional Backend Papercut Service Load on Windows Startup Attachments/Mime SectionsExperfwiz (Exchange Performance Data Collection tool): Experfwiz 1.3.8: List of updates in 1.3.8 Added support for Windows 2012 & 2012 R2 (for future use) Added support for Exchange 2013 Full is now enabled by default. To disable full mode, use 'nofull'. Exchange 2013 requires full. Added "\Processor Information()\" counters to Exchange 2010 full Blocked Exmon execution on Exchange 2013BugNET Issue Tracker: BugNET 1.6: Version 1.6 is a major upgrade to the latest frameworks and components by Microsoft. It includes a major UI overhaul using the bootstrap framework to have a modern, mobile friendly and easily customized layout. Upgrade to .NET 4.5 ASP.NET social auth Add script bundling and optimization Improvements for mobile devices Bootstrap (UI overhaul) Rewritten / friendly URL's Please read our release notes for BugNET 1.6: http://blog.bugnetproject.com/2014/06/08/bugnet-1-6-and-bugnet-pro-1...NDataTable: NDataTable Source Code: Source codeWindows System API in Visual Basic: DataTools Merged Beta 2.4: Added FileSystemWatcher and demonstration to this release..NET Memory Tools: DataTools Merged Beta 2.4: Added FileSystemWatcher and demonstration to this release.freeasyExplorer: 3. Alpha: This is the 3th alpha release. Please inform me if you find some issues or problems. Fixes: - add assembly informations - set list view to list mode and add custom icon - add settings window - update Mahapp.Metro Framework - add drag&drop functionality - change target .net versionkbvault-mysql: V0.16a: Additions for SEO friendly pages,printer friendly view option and tag cloud on landing pageSFDL.NET: SFDL.NET (2.2.9.3): Changelog: Retry Bugfix (Error Counter wurde nicht korrekt zurückgesetzt) Neue Einstellung: Retry Wartezeit ist nun Einstellbarbabelua: 1.5.7.0: V1.5.7.0 - 2014.6.6Stability improvement: use "lua scripts folder" as lua search path when debugging;SEToolbox: SEToolbox 01.033.007 Release 1: Fixed breaking changes in Space Engineers in latest update. Installation of this version will replace older version.Virto Commerce Enterprise Open Source eCommerce Platform (asp.net mvc): Virto Commerce 1.10: Virto Commerce Community Edition version 1.10. To install the SDK package, please refer to SDK getting started documentation To configure source code package, please refer to Source code getting started documentation This release includes bug fixes and improvements (including Commerce Manager localization and https support). More details about this release can be found on our blog at http://blog.virtocommerce.com.NPOI: NPOI 2.1: Assembly Version: 2.1.0 New Features a. XSSFSheet.CopySheet b. Excel2Html for XSSF c. insert picture in word 2007 d. Implement IfError function in formula engine Bug Fixes a. fix conditional formatting issue b. fix ctFont order issue c. fix vertical alignment issue in XSSF d. add IndexedColors to NPOI.SS.UserModel e. fix decimal point issue in non-English culture f. fix SetMargin issue in XSSF g.fix multiple images insert issue in XSSF h.fix rich text style missing issue in XSSF i. fix cell...51Degrees - Device Detection and Redirection: 3.1.2.3: Version 3.1 HighlightsDevice detection algorithm is over 100 times faster. Regular expressions and levenshtein distance calculations are no longer used. The device detection algorithm performance is no longer limited by the number of device combinations contained in the dataset. Two modes of operation are available: Memory – the detection data set is loaded into memory and there is no continuous connection to the source data file. Slower initialisation time but faster detection performanc...CS-Script for Notepad++ (C# intellisense and code execution): Release v1.0.27.0: CodeMap now indicates the type name for all members Implemented running scripts 'as administrator'. Just add '//css_npp asadmin' to the script and run it as usual. 'Prepare script for distribution' now aggregates script dependency assemblies. Various improvements in CodeSnipptet, Autcompletion and MethodInfo interactions with each other. Added printing line number for the entries in CodeMap (subject of configuration value) Improved debugging step indication for classless scripts ...ClosedXML - The easy way to OpenXML: ClosedXML 0.72.3: 70426e13c415 ClosedXML for .Net 4.0 now uses Open XML SDK 2.5 b9ef53a6654f Merge branch 'master' of https://git01.codeplex.com/forks/vbjay/closedxml 727714e86416 Fix range.Merge(Boolean) for .Net 3.5 eb1ed478e50e Make public range.Merge(Boolean checkIntersects) 6284cf3c3991 More performance improvements when saving.DNN Blog: 06.00.07: Highlights: Enhancement: Option to show management panel on child modules Fix: Changed SPROC and code to ensure the right people are notified of pending comments. (CP-24018) Fix: Fix to have notification actions authentication assume the right module id so these will work from the messaging center (CP-24019) Fix: Fix to issue in categories in a post that will not save when no categories and no tags selectedNew ProjectsATC FSX Console: Flight Simulator CodeCRM 2011 Duplicate Detection Sample: CRM 2011 Duplicate Detection Plug-in SampleCustomisation tool for Visual Studio projects: This tool is used to speedup the setting up of a Visual Studio projects and suppress any repetitive manual tasks.D3 Focus: A basic tool for people with trouble deciding what to do with their time in Diablo 3.EPS - PowerShell templating: EPS (Embedded PowerShell), inspired by erb, is a templating system that embeds PowerShell code into a text document such as HTML files. Export Bugs: Export Bugs is an application using the TFS API. Killer Bytes Pack: project of class visual studioMagickViewer: An application that uses the Magick.NET library to display images.Mario Card: https://drive.google.com/?authuser=0#folders/0B0VMM5klwOkwLXptMVV6b3NhRVEOZone: OZonePlexApp PowerShell Module: PoSH4PlexApp is an in-development PowerShell module for querying and managing PlexApp libraries via Plex Media Server's HTTP listener. Contributions welcomeProduct Usage Tracker: This project is about creating a tool/mechanism to capture and record the usage volume and usage patterns of any application.Project C²: A simple lightweight C-style programming language for near-hardware system development using GNU GAS as a back-end.Random Execute: Random Execute is a command wrapper that randomizes the start time of a processes execution.RuLaw.NET: .NET library for official Russian State Duma API web service for querying and searching information of laws, deputies, authorities, sessions, votings, etcTest_DB_Name_Check: Latestweb_gioman_proyecto: proyecto de lucas gioiaWPF Globalization and Multi-language Application: Multilingual User Interfaces providing support for switching UIs from one language to another. ??????-??????【??】: ????????,??????:?????,?????,??????,??????????,????????。????????!??????-??????【??】: ?????????????????????????????,??????????,????,????,?????????、??????,??????。?????-?????【??】: ???????????????????,??????????,????????、????,??????????,??????????。?????-?????【??】: ?????????????????、????,??100%????,??????,????????????,???????????!?????-?????【??】: ??????????????????????:????、????、??????????????,????????。????????!??????-??????【??】: ??????????????????????????,????,????,??????????。???????????????,??,??,??????????,????????????-??????【??】: ???????????????????,?????????????,????,?????????,?????????????,?????,?????!??????-??????【??】: ??????????????????,???????????,??????????????,??????????，??????????????！?????-?????【??】: ????【??:13406937288 ??? QQ:798761615】???????????????,???,??????????、???????????????????。??????,????、????，??????！ ?????-?????【??】: ???????????????,?????????????? ??。????????、????、????、?????????? ???????。?????-?????【??】: ????????????????,???????????????。???????????,??????:????、????、????????????-?????【??】: ???????【??:13406937288 ??? QQ:798761615】?????????????????,????,????“???、???、???”?????,?????,?????????????????。??????！?????-?????【??】: ?????????【??:13406937288 ??? QQ:798761615】,???????????,??????????,????:??,????,???????? ??????????,????????。??????！?????-?????【??】: ?????【??:13406937288 ??? QQ:798761615】????:?????,??????!???????????????,???????、?????、??????“??”????,????,????!?????-?????【??】: ???????【??:13406937288 ??? QQ:798761615】???????,??????,??????,??????、??????,??????、??，????，????????????-??????【??】: ?????????【??:13406937288 ??? QQ:798761615】????????????????????,???????????,??????,??????????????...????????。??????！?????-?????【??】: ???????【??:13406937288 ??? QQ:798761615】?????????、?????????,??????、??????????????????,???????.??????????,????????。??????-??????【??】: ?????????????????,??????????、??????,??????????、????、????、???????。??????-??????【??】: ??????????????????????,???????????????,???????,?????,?????,????? !!!?????-?????【??】: ???????【??:13406937288 ??? QQ:798761615】????????,????,?????、???、?????,???????,?????,???????????100%。??????！????-????【??】: ???????????、??????????????????,????????,?????,??????,????,????,????!?????-?????【??】: ?????????????????????,???????????????,????????????????????!?????-?????【??】: ?????????【??:13406937288 ??? QQ:798761615】???2005?,????????????????????,??????????,??????。?????,???????????????????，??????！?????-?????【??】: ???????【??:13406937288 ??? QQ:798761615】???????:??????!?????!???:????、????、????、????。??,??????????!??????.?????-?????【??】: ???????【??:13406937288 ??? QQ:798761615】??????????,????????????,????????,???,???????????,????,????。?????,??????. ?????-?????【??】: ?????????????????:??????!?????!???:????、????、????、????。??,??????????!??????.?????-?????【??】: ???????【??:13406937288 ??? QQ:798761615】 ?????????????????,????,????“???、???、???”?????,?????,?????????????????。??????！?????-?????【??】: ???????【??:13406937288 ??? QQ:798761615】?????????????,??????,???????????,????????????????,????????.??????.?????-?????【??】: ???????【??:13406937288 ??? QQ:798761615】???1992?,????????????????。??????????????????????。????????????,????，????????！?????-?????【??】: ?????【??:13406937288 ??? QQ:798761615】??????:?????,??????!???????????????,???????、?????、??????“??”????,????,????! ?????-?????【??】: ???????【??:13406937288 ??? QQ:798761615】????????,????,?????、???、?????,???????,?????,???????????100%。??????！??????-??????【??】: ????????【??:13406937288 ??? QQ:798761615】?????????、?????????,??????、??????????????????,???????.??????????,????????。?????-?????【??】: ???????【??:13406937288 ??? QQ:798761615】???1992?,????????????????。??????????????????????。????????????,????，????????！ ?????-?????【??】: ?????????【??:13406937288 ??? QQ:798761615】???2005?,????????????????????,??????????,??????。?????,???????????????????，??????！?????-?????【??】: ???????【??:13406937288 ??? QQ:798761615】??????????????????,???????????,??????,??????????????...????????。??????！?????-?????【??】: ?????????????【??:13406937288 ??? QQ:798761615】?????????????,??????,???????????,????????????????,????????.??????.??????-??????【??】: ???????????,?????,???????????,???????,????,????,????,?????。??????-??????【??】: ????????????????8?，????????,????????,??????????,?????,????? ,????????!??????-??????【??】: ????????????????6?,???????????????????????????,??????????????,?????????！?????-?????【??】: ?????????????【??:13406937288 ??? QQ:798761615】???????,??????,??????,??????、??????,??????、??，????，??????！?????-?????【??】: ???????????、???、??、??????????????????????????????,????????????????!?????-?????【??】: ????????????????????????????、????、????、???????????,????,????!?????-?????【??】: ???????【??:13406937288 ??? QQ:798761615】?????????????????,????,????“???、???、???”?????,?????,?????????????????。??????！?????-?????【??】: ???????【??:13406937288 ??? QQ:798761615】??????????,????????????,????????,???,???????????,????,????。?????,??????.

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• LOD in modern games

  - by Firas Assaad

  I'm currently working on my master's thesis about LOD and mesh simplification, and I've been reading many academic papers and articles about the subject. However, I can't find enough information about how LOD is being used in modern games. I know many games use some sort of dynamic LOD for terrain, but what about elsewhere? Level of Detail for 3D Graphics for example points out that discrete LOD (where artists prepare several models in advance) is widely used because of the performance overhead of continuous LOD. That book was published in 2002 however, and I'm wondering if things are different now. There has been some research in performing dynamic LOD using the geometry shader (this paper for example, with its implementation in ShaderX6), would that be used in a modern game? To summarize, my question is about the state of LOD in modern video games, what algorithms are used and why? In particular, is view dependent continuous simplification used or does the runtime overhead make using discrete models with proper blending and impostors a more attractive solution? If discrete models are used, is an algorithm used (e.g. vertex clustering) to generate them offline, do artists manually create the models, or perhaps a combination of both methods is used?

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• Is there a shell-independent HUD-like menu search tool for Xfce/GNOME/Cinnamon?

  - by Redsandro

  The Ubuntu Heads-Up Display (HUD) - you love it or you hate it. Personally I rather like a classic desktop, so I use Xfce or GNOME-fork Cinnamon, and I'd like to keep those menu's where they are. But the HUD is pretty awesome when your menus are complex and you forgot where an option sits. This makes that search trick very interesting. I know the HUD is Unity specific. I am looking for a HUD-like tool to complement the menu in shells other than Unity. There is Appmenu Runner for KDE that does this. There is also appmenu-qt for KDE. Problem with the above is that it uses KDE libs, and it only works for KDE apps. This is Linux, there aught to be something like this for GNOME/GTK apps, right? Looking for any tool that can search the menus. I already use(d) Synapse, Kupfer and GNOME Do, but those are simply app-launchers (with some tricks). Something like that would suffice if only they included searching the menus for the currently focused application. The HUD allows users to activate menu items by typing part of the name. It uses a fuzzy search algorithm that will highlight partial matches. It can match menu items that are multiple layers deep in an application's menu hierarchy. The feature, which replaces traditional menu accelerators, is activated by pressing the alt key. Similar questions: Is there a way to search a menu bar in Debian? - Unix.StackExchange How can I access menu bar items alike hud (unity)? - Unix.StackExchange HUD in other window managers (especially xmonad) - AskUbuntu

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• Efficiently rendering to 3D texture

  - by TravisG

  I have an existing depth texture and some other color textures, and want to process the information in them by rendering to a 3D texture (based on the depth contained in the depth texture, i.e. a point at (x/y) in the depth texture will be rendered to (x/y/texture(depth,uv)) in the 3D texture). Simply doing one manual draw call for each slice of the 3D texture (via glFramebufferTextureLayer) is terribly slow, since I don't know beforehand to what slice of the 3D texture a given texel from one of the color textures or the depth texture belongs. This means the entire process is effectively for each slice for each texel in depth texture process color textures and render to slice So I have to sample the depth texture completely per each slice, and I also have to go through the processing (at least until to discard;) for all texels in it. It would be much faster if I could rearrange the process to for each texel in depth texture figure out what slice it should end up in process color textures and render to slice Is this possible? If so, how? What I'm actually trying to do: the color textures contain lighting information (as seen from light view, it's a reflective shadow map). I want to accumulate that information in the 3D texture and then later use it to light the scene. More specifically I'm trying to implement Cryteks Light Propagation Volumes algorithm.

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• How does the new google maps make buildings and cityscapes 3D?

  - by Aerovistae

  Anyone who's seen the new Google maps has no doubt taken note of the incredible amount of three-dimensional detail in select American cities such as Boston, New York, Chicago, and San Francisco. They've even modeled the trees, bridges and some of the boats in the harbor! Minor architectural details are present. It's crazy. Looking at it up close, I've found there's a rectangular area around each of those cities, and anything within them is 3Dified, but it cuts off hard and fast at the edge, even if it's in the middle of a building. The edge of the rectangle is where the 3D stops. This leads me to think it's being done algorithmically (which would make sense, given the scale of the project, how many trees and buildings and details there are), and yet I can't imagine how that's possible. How could an algorithm model all these things without extensive data on their shapes and contours? How could it model the individual wires of a bridge, or the statues in a park? It must be done by hand, and yet how could it be for so much detail! Does anyone have any insight on this?

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• How to make it so units don't stack up in one location?

  - by Daggio

  So I'm making a game in AS3, it's a strategy DotA-like game (for flash game equivalent, there's UDE) so far so good, I have the A* pathfinding algorithm all sorted out and the minion units move to the desired location as I want them to be. The problem a rise when a unit stops in a node that has already occupied by another friendly unit. Both (or more than two) of them stacks up in one location, it looks like they're one unit. I want to add collision detection so when they collide they don't stack up together. But now they stop when they collide on they way to a node. This isn't good because they won't move at all midway (they won't respond to enemy attacks like that). I've added a deltatime so they only stopped for 2 seconds before they move again to their designated designation. This moves them again but they flicker. Not how I want it. So, like the title said. How to make more than one units don't stack up in a node? And if possible, how to make them not flicker while moving (it's good if they can tell other friendly units on the way and avoid them accordingly)?

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• Problem inserting pre-ordered values to quadtree

  - by Lucas Corrêa Feijó

  There's this string containing B, W and G (standing for black, white and gray). It defines the pre-ordered path of the quadtree I want to build. I wrote this method for filling the QuadTree class I also wrote but it doesn't work, it inserts correctly until it reaches a point in the algorithm it needs to "return". I use math quadrants convention order for insertion, such as northeast, northwest, southwest and southeast. A quadtree has all it's leafs black or white and all the other nodes gray The node used in the tree is called Node4T and has a char as data and 4 references to other nodes like itself, called, respectively NE, NW, SW, SE. public void insert(char val) { if(root==null) { root = new Node4T(val); } else { insert(root, val); } } public void insert(Node4T n, char c) { if(n.data=='G') // possible to insert { if(n.NE==null) { n.NE = new Node4T(c); return; } else { insert(n.NE,c); } if(n.NW==null) { n.NW = new Node4T(c); return; } else { insert(n.NW,c); } if(n.SW==null) { n.SW = new Node4T(c); return; } else { insert(n.SW,c); } if(n.SE==null) { n.SE = new Node4T(c); return; } else { insert(n.SE,c); } } else // impossible to insert { } } The input "GWGGWBWBGBWBWGWBWBWGGWBWBWGWBWBGBWBWGWWWB" is given a char at a time to the insert method and then the print method is called, pre-ordered, and the result is "GWGGWBWBWBWGWBWBW". How do I make it import the string correctly? Ignore the string reading process, suppose the method is called and it has to do it's job.

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• Processing Kinect v2 Color Streams in Parallel

  - by Chris Gardner

  Originally posted on: http://geekswithblogs.net/freestylecoding/archive/2014/08/20/processing-kinect-v2-color-streams-in-parallel.aspxProcessing Kinect v2 Color Streams in Parallel I've really been enjoying being a part of the Kinect for Windows Developer's Preview. The new hardware has some really impressive capabilities. However, with great power comes great system specs. Unfortunately, my little laptop that could is not 100% up to the task; I've had to get a little creative. The most disappointing thing I've run into is that I can't always cleanly display the color camera stream in managed code. I managed to strip the code down to what I believe is the bear minimum: using( ColorFrame _ColorFrame = e.FrameReference.AcquireFrame() ) { if( null == _ColorFrame ) return;   BitmapToDisplay.Lock(); _ColorFrame.CopyConvertedFrameDataToIntPtr( BitmapToDisplay.BackBuffer, Convert.ToUInt32( BitmapToDisplay.BackBufferStride * BitmapToDisplay.PixelHeight ), ColorImageFormat.Bgra ); BitmapToDisplay.AddDirtyRect( new Int32Rect( 0, 0, _ColorFrame.FrameDescription.Width, _ColorFrame.FrameDescription.Height ) ); BitmapToDisplay.Unlock(); } With this snippet, I'm placing the converted Bgra32 color stream directly on the BackBuffer of the WriteableBitmap. This gives me pretty smooth playback, but I still get the occasional freeze for half a second. After a bit of profiling, I discovered there were a few problems. The first problem is the size of the buffer along with the conversion on the buffer. At this time, the raw image format of the data from the Kinect is Yuy2. This is great for direct video processing. It would be ideal if I had a WriteableVideo object in WPF. However, this is not the case. Further digging led me to the real problem. It appears that the SDK is converting the input serially. Let's think about this for a second. The color camera is a 1080p camera. As we should all know, this give us a native resolution of 1920 x 1080. This produces 2,073,600 pixels. Yuy2 uses 4 bytes per 2 pixel, for a buffer size of 4,147,200 bytes. Bgra32 uses 4 bytes per pixel, for a buffer size of 8,294,400 bytes. The SDK appears to be doing this on one thread. I started wondering if I chould do this better myself. I mean, I have 8 cores in my system. Why can't I use them all? The first problem is converting a Yuy2 frame into a Bgra32 frame. It is NOT trivial. I spent a day of research of just how to do this. In the end, I didn't even produce the best algorithm possible, but it did work. After I managed to get that to work, I knew my next step was the get the conversion operation off the UI Thread. This was a simple process of throwing the work into a Task. Of course, this meant I had to marshal the final write to the WriteableBitmap back to the UI thread. Finally, I needed to vectorize the operation so I could run it safely in parallel. This was, mercifully, not quite as hard as I thought it would be. I had my loop return an index to a pair of pixels. From there, I had to tell the loop to do everything for this pair of pixels. If you're wondering why I did it for pairs of pixels, look back above at the specification for the Yuy2 format. I won't go into full detail on why each 4 bytes contains 2 pixels of information, but rest assured that there is a reason why the format is described in that way. The first working attempt at this algorithm successfully turned my poor laptop into a space heater. I very quickly brought and maintained all 8 cores up to about 97% usage. That's when I remembered that obscure option in the Task Parallel Library where you could limit the amount of parallelism used. After a little trial and error, I discovered 4 parallel tasks was enough for most cases. This yielded the follow code: private byte ClipToByte( int p_ValueToClip ) { return Convert.ToByte( ( p_ValueToClip < byte.MinValue ) ? byte.MinValue : ( ( p_ValueToClip > byte.MaxValue ) ? byte.MaxValue : p_ValueToClip ) ); }   private void ColorFrameArrived( object sender, ColorFrameArrivedEventArgs e ) { if( null == e.FrameReference ) return;   // If you do not dispose of the frame, you never get another one... using( ColorFrame _ColorFrame = e.FrameReference.AcquireFrame() ) { if( null == _ColorFrame ) return;   byte[] _InputImage = new byte[_ColorFrame.FrameDescription.LengthInPixels * _ColorFrame.FrameDescription.BytesPerPixel]; byte[] _OutputImage = new byte[BitmapToDisplay.BackBufferStride * BitmapToDisplay.PixelHeight]; _ColorFrame.CopyRawFrameDataToArray( _InputImage );   Task.Factory.StartNew( () => { ParallelOptions _ParallelOptions = new ParallelOptions(); _ParallelOptions.MaxDegreeOfParallelism = 4;   Parallel.For( 0, Sensor.ColorFrameSource.FrameDescription.LengthInPixels / 2, _ParallelOptions, ( _Index ) => { // See http://msdn.microsoft.com/en-us/library/windows/desktop/dd206750(v=vs.85).aspx int _Y0 = _InputImage[( _Index << 2 ) + 0] - 16; int _U = _InputImage[( _Index << 2 ) + 1] - 128; int _Y1 = _InputImage[( _Index << 2 ) + 2] - 16; int _V = _InputImage[( _Index << 2 ) + 3] - 128;   byte _R = ClipToByte( ( 298 * _Y0 + 409 * _V + 128 ) >> 8 ); byte _G = ClipToByte( ( 298 * _Y0 - 100 * _U - 208 * _V + 128 ) >> 8 ); byte _B = ClipToByte( ( 298 * _Y0 + 516 * _U + 128 ) >> 8 );   _OutputImage[( _Index << 3 ) + 0] = _B; _OutputImage[( _Index << 3 ) + 1] = _G; _OutputImage[( _Index << 3 ) + 2] = _R; _OutputImage[( _Index << 3 ) + 3] = 0xFF; // A   _R = ClipToByte( ( 298 * _Y1 + 409 * _V + 128 ) >> 8 ); _G = ClipToByte( ( 298 * _Y1 - 100 * _U - 208 * _V + 128 ) >> 8 ); _B = ClipToByte( ( 298 * _Y1 + 516 * _U + 128 ) >> 8 );   _OutputImage[( _Index << 3 ) + 4] = _B; _OutputImage[( _Index << 3 ) + 5] = _G; _OutputImage[( _Index << 3 ) + 6] = _R; _OutputImage[( _Index << 3 ) + 7] = 0xFF; } );   Application.Current.Dispatcher.Invoke( () => { BitmapToDisplay.WritePixels( new Int32Rect( 0, 0, Sensor.ColorFrameSource.FrameDescription.Width, Sensor.ColorFrameSource.FrameDescription.Height ), _OutputImage, BitmapToDisplay.BackBufferStride, 0 ); } ); } ); } } This seemed to yield a results I wanted, but there was still the occasional stutter. This lead to what I realized was the second problem. There is a race condition between the UI Thread and me locking the WriteableBitmap so I can write the next frame. Again, I'm writing approximately 8MB to the back buffer. Then, I started thinking I could cheat. The Kinect is running at 30 frames per second. The WPF UI Thread runs at 60 frames per second. This made me not feel bad about exploiting the Composition Thread. I moved the bulk of the code from the FrameArrived handler into CompositionTarget.Rendering. Once I was in there, I polled from a frame, and rendered it if it existed. Since, in theory, I'm only killing the Composition Thread every other hit, I decided I was ok with this for cases where silky smooth video performance REALLY mattered. This ode looked like this: private byte ClipToByte( int p_ValueToClip ) { return Convert.ToByte( ( p_ValueToClip < byte.MinValue ) ? byte.MinValue : ( ( p_ValueToClip > byte.MaxValue ) ? byte.MaxValue : p_ValueToClip ) ); }   void CompositionTarget_Rendering( object sender, EventArgs e ) { using( ColorFrame _ColorFrame = FrameReader.AcquireLatestFrame() ) { if( null == _ColorFrame ) return;   byte[] _InputImage = new byte[_ColorFrame.FrameDescription.LengthInPixels * _ColorFrame.FrameDescription.BytesPerPixel]; byte[] _OutputImage = new byte[BitmapToDisplay.BackBufferStride * BitmapToDisplay.PixelHeight]; _ColorFrame.CopyRawFrameDataToArray( _InputImage );   ParallelOptions _ParallelOptions = new ParallelOptions(); _ParallelOptions.MaxDegreeOfParallelism = 4;   Parallel.For( 0, Sensor.ColorFrameSource.FrameDescription.LengthInPixels / 2, _ParallelOptions, ( _Index ) => { // See http://msdn.microsoft.com/en-us/library/windows/desktop/dd206750(v=vs.85).aspx int _Y0 = _InputImage[( _Index << 2 ) + 0] - 16; int _U = _InputImage[( _Index << 2 ) + 1] - 128; int _Y1 = _InputImage[( _Index << 2 ) + 2] - 16; int _V = _InputImage[( _Index << 2 ) + 3] - 128;   byte _R = ClipToByte( ( 298 * _Y0 + 409 * _V + 128 ) >> 8 ); byte _G = ClipToByte( ( 298 * _Y0 - 100 * _U - 208 * _V + 128 ) >> 8 ); byte _B = ClipToByte( ( 298 * _Y0 + 516 * _U + 128 ) >> 8 );   _OutputImage[( _Index << 3 ) + 0] = _B; _OutputImage[( _Index << 3 ) + 1] = _G; _OutputImage[( _Index << 3 ) + 2] = _R; _OutputImage[( _Index << 3 ) + 3] = 0xFF; // A   _R = ClipToByte( ( 298 * _Y1 + 409 * _V + 128 ) >> 8 ); _G = ClipToByte( ( 298 * _Y1 - 100 * _U - 208 * _V + 128 ) >> 8 ); _B = ClipToByte( ( 298 * _Y1 + 516 * _U + 128 ) >> 8 );   _OutputImage[( _Index << 3 ) + 4] = _B; _OutputImage[( _Index << 3 ) + 5] = _G; _OutputImage[( _Index << 3 ) + 6] = _R; _OutputImage[( _Index << 3 ) + 7] = 0xFF; } );   BitmapToDisplay.WritePixels( new Int32Rect( 0, 0, Sensor.ColorFrameSource.FrameDescription.Width, Sensor.ColorFrameSource.FrameDescription.Height ), _OutputImage, BitmapToDisplay.BackBufferStride, 0 ); } }

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• Player sprite moving slower on iPhone 4

  - by nvillec

  I just finished getting movement/jump animation for a player sprite in Xcode using Cocos2D. The basic movement algorithm is a timer that updates every 0.01 sec, changing the sprite position to (sprite.position.x + xVel, sprite.position.y + yVel). Each time a movement button is tapped, the appropriate velocity (initialized to 0) is changed to whatever speed I choose, then a stop movement button returns the velocity to 0. It's not an ideal solution but I'm very new at this and stoked to at least have that working with little help from the internet. So I may not have explained that perfectly, but it is in fact working to my satisfaction in Xcode's iPhone Simulator, however when I build it for my device and run it on my phone, the sprite's movement speed is noticeably slower than in Xcode. At first I thought it must have to do with the resolution of the iPhone 4, making the sprite's movement path twice as long, but I found that if I pull up the multitask bar, then return to the app the speed will sometimes jump back to normal. My second theory was that the code is just inefficient and is bogging the processes down, but I would see this reflected in the frame rate wouldn't I? It stays at 59-60 the whole time, and the spritesheet animation runs at the correct speed. Has anyone experienced this? Is this a really obvious issue that I'm completely missing? Any help (or tips for optimizing my approach to movement) would be much appreciated!

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• What is a Coding Dojo?

  - by huwyss

  Recently i found out that there is a thing called "coding dojo". The point behind it is that software developers want to have a space to learn new stuff like processes, methods, coding details, languages, and whatnot in an environment without stress. Just for fun. No competition. No results required. No deadlines.Some days ago I joined the Zurich coding dojo. We were three programmers with different backgrounds.We gave ourselves the task to develop a method that takes an input value and returns its prime factors. We did pair programming and every few minutes we switched positions. We used test driven development. The chosen programming language was Ruby.I haven't really done TDD before. It was pretty interesting to see the algorithm develop following the testcases.We started with the first test input=1 then developed the most simple productive program that passed this very first test. Then we added the next test input=2 and implemented the productive code. We kept adding tests and made sure all tests are passed until we had the general solution.When we improved the performance of our code we saw the value of the tests we wrote before. Of course our first performance improvement broke several tests.It was a very interesting experience to see how other developers think and how they work. I will participate at the dojo again and can warmly recommend it to anyone. There are  coding dojos all over the world.Have fun!

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• What technical test should I give to a job candidate

  - by Romain Braun

  I'm not sure if this is the right stackexhange website, but : I have three candidates coming in tomorrow. One has 15 years of experience in PHP, and the two others have about 1 year of experience in PHP/ frontend development. For the last ones I was thinking about a test where they would have to develop a web app allowing users to manage other users, as in : Display a list of users, display a single user, modify an user, and add extended properties to an user. This way it would feature html, css, js, ajax, php and SQL. Do you think this would be a good test? What test should I give to the first one? He needs something much more difficult, I guess. I'm also listening, if you have any advice/ideas about what makes a good developer, and what I should pay attention to in the guys' codes. I was also considering thinking outside of the box, more algorithm-related, and asked him to make the fastest function to tell if a number is a prime number, because there are a lot of optimizations you can apply to such a function. They have one day to do it.

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• Get 100 highest numbers from an infinite list

  - by Sachin Shanbhag

  One of my friend was asked this interview question - "There is a constant flow of numbers coming in from some infinite list of numbers out of which you need to maintain a datastructure as to return the top 100 highest numbers at any given point of time. Assume all the numbers are whole numbers only." This is simple, you need to keep a sorted list in descending order and keep a track on lowest number in that list. If new number obtained is greater than that lowest number then you have to remove that lowest number and insert the new number in sorted list as required. Then question was extended - "Can you make sure that the Order for insertion should be O(1)? Is it possible?" As far as I knew, even if you add a new number to list and sort it again using any sort algorithm, it would by best be O(logn) for quicksort (I think). So my friend told it was not possible. But he was not convinced, he asked to maintain any other data structure rather than a list. I thought of balanced Binary tree, but even there you will not get the insertion with order of 1. So the same question I have too now. Wanted to know if there is any such data structure which can do insertion in Order of 1 for above problem or it is not possible at all.

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• A Star Path finding endless loop

  - by PoeHaH

  I have implemented A* algorithm. Sometimes it works, sometimes it doesn't, and it goes through an endless loop. After days of debugging and googling, I hope you can come to the rescue. This is my code: The algorythm: public ArrayList<Coordinate> findClosestPathTo(Coordinate start, Coordinate goal) { ArrayList<Coordinate> closed = new ArrayList<Coordinate>(); ArrayList<Coordinate> open = new ArrayList<Coordinate>(); ArrayList<Coordinate> travelpath = new ArrayList<Coordinate>(); open.add(start); while(open.size()>0) { Coordinate current = searchCoordinateWithLowestF(open); if(current.equals(goal)) { return travelpath; } travelpath.add(current); open.remove(current); closed.add(current); ArrayList<Coordinate> neighbors = current.calculateCoordAdjacencies(true, rowbound, colbound); for(Coordinate n:neighbors) { if(closed.contains(n) || map.isWalkeable(n)) { continue; } int gScore = current.getGvalue() + 1; boolean gScoreIsBest = false; if(!open.contains(n)) { gScoreIsBest = true; n.setHvalue(manhattanHeuristic(n,goal)); open.add(n); } else { if(gScore<n.getGvalue()) { gScoreIsBest = true; } } if(gScoreIsBest) { n.setGvalue(gScore); n.setFvalue(n.getGvalue()+n.getHvalue()); } } } return null; } What I have found out is that it always fails whenever there's an obstacle in the path. If I'm running it on 'open terrain', it seems to work. It seems to be affected by this part: || map.isWalkeable(n) Though, the isWalkeable function seems to work fine. If additional code is needed, I will provide it. Your help is greatly appreciated, Thanks :)

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• One Step-Ahead A-Star

  - by Jonathan Dickinson

  I am attempting to create a server-centric RTS (as opposed to usual parallel synchronised simulation route of most RTS games today) - however I am still leveraging the discreet N-turns-ahead paradigm discussed by one of the AOE developers on Gamasutra. I have [possibly questionably?] decided that the path finding should only ever find the next cell the entity needs to move to, and was wondering if anyone has any clever ideas on how to optimize the algorithm for this specific scenario - or any other ideas on how to keep the pathfinding as lean as possible on the server. I have investigated a few possible algorithms but could only come up with one appropriation: Tiered A-Star - Relatively large T1 tiles, work out (and cache) each cell as you enter it. Other than that: doing the full A-Star pass and caching the entire path, which might use too much memory if a large amount of units are present. I know about the existence of naive progressive pathfinding algorithms (if you hit a block, turn in the direction closer to your target etc.) but they suffer from infinite feedback loops - and very poor pathing even if visited blocks are memorised. Not an option. Many thanks.

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• Moving objects colliding when using unalligned collision avoidance (steering)

  - by James Bedford

  I'm having trouble with unaligned collision avoidance for what I think is a rare case. I have set two objects to move towards each other but with a slight offset, so one of the objects is moving slightly upwards, and one of the objects is moving slightly downwards. In my unaligned collision avoidance steering algorithm I'm finding the points on the object's forward line and the other object's forward line where these two lines are the closest. If these closest points are within a collision avoidance distance, and if the distance between them is smaller than the two radii of the two object's bounding spheres, then the objects should steer away in the appropriate direction. The problem is that for my case, the closest points on the lines are calculated to be really far away from the actual collision point. This is because the two forward lines for each object are moving away from each other as the objects pass. The problem is that because of this, no steering takes place, and the two objects partially collide. Does anyone have any suggestions as to how I can correctly calculate the point of collision? Perhaps by somehow taking into account the size of the two objects?

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• Why it is called "hash table", or "hash function"? Hash doesn't make any sense to me here

  - by Saeed Neamati

  It's now about 4 years of development that I'm using, hearing, talking about, and implementing hash tables and hash functions. But I really never understand why it's called hash? I remember the first days I started programming, this term was kind'of cumbersome terminology to me. I never figured out what is it, based on its name. I just experimentally understood what it does and why and when should we use it. However, I still sometimes try to figure out why it's called hash. I have no problem with table or function and to be honest, they are pretty deductive, rational terms. However, I think better words could be used instead of hash, like key, or uniqueness. Don't key table or uniqueness table. According to my dictionary, hash means: Fried dish of potato and meats (highly irrelevant) # symbol (AKA number sign, pound sign, etc.) (still irrelevant, maybe just a mis-nomenclature) Apply algorithm to character string (still has nothing to do with uniqueness, which is the most important feature of a hash table) Cut food Another term for hashish Does anyone know why it's called hash?

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• ArchBeat Link-o-Rama for December 4, 2012

  - by Bob Rhubart

  Exalogic 2.0.1 Tea Break Snippets - Creating and using Distribution Groups | The Old Toxophilist "Although in many cases we, as Cloud Users, may not be to worried how the Virtualisation Algorithm decides where to place our vServers," says The Old Toxopholist, "there are cases where it is extremely important that vServers run on distinct physical compute nodes." There's plenty more on the subject in his blog post. Oracle Endeca (2.3) Record Level Security | Adam Seed Adam Sneed's blog post covers "the basics of security within Endeca Information Discovery, as these basic security objects are required in order to explain the implementation of record level security." ODI Handling DQ | Gurcan Orhan Oracle ACE Director Gurcan Orhan suggests you have fun with these scripts for Oracle Data Integrator. Parleys Testimonial at GlassFish Community Event - JavaOne 2012 Video of Parley's webmaster Stephan Janssen's presentation at the GlassFish Community Event at JavaOne 2012, in which he explains why Parley's moved from Tomcat to GlassFish. Java Spotlight Episode 109: Pete Muir on CDI 1.1 This edition of Roger Brinkley's Java Spotlight Podcast features an interview with CDI 1.1 spec lead Pete Muir of JBoss/Red Hat. Muir talks about the features in CDI 1.1 and what to expect in the future. Webcast: Java Management Extensions with Oracle WebLogic Server 12c Dr. Frank Munz and Dave Cabelus do the talking in this on-demand webcast focused on Oracle WebLogic Server 12c with Java Management Extensions (JMX). Using the Coherence API to get Portable Object Format bytes | Bruno Borges Bruno Borges shares a code snippet that illustrates how easy it is to use the Coherence API. Thought for the Day "Experience is something you don't get until just after you need it." — Anonymous Source: SoftwareQuotes.com

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• How to store bitmaps in memory?

  - by Geotarget

  I'm working with general purpose image rendering, and high-performance image processing, and so I need to know how to store bitmaps in-memory. (24bpp/32bpp, compressed/raw, etc) I'm not working with 3D graphics or DirectX / OpenGL rendering and so I don't need to use graphics card compatible bitmap formats. My questions: What is the "usual" or "normal" way to store bitmaps in memory? (in C++ engines/projects?) How to store bitmaps for high-performance algorithms, such that read/write times are the fastest? (fixed array? with/without padding? 24-bpp or 32-bpp?) How to store bitmaps for applications handling a lot of bitmap data, to minimize memory usage? (JPEG? or a faster [de]compression algorithm?) Some possible methods: Use a fixed packed 24-bpp or 32-bpp int[] array and simply access pixels using pointer access, all pixels are allocated in one continuous memory chunk (could be 1-10 MB) Use a form of "sparse" data storage so each line of the bitmap is allocated separately, reusing more memory and requiring smaller contiguous memory segments Store bitmaps in its compressed form (PNG, JPG, GIF, etc) and unpack only when its needed, reducing the amount of memory used. Delete the unpacked data if its not used for 10 secs.

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