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• Rob Blackwell on interoperability and Azure

  - by Eric Nelson

  At QCon in March we had a sample Azure application implemented in both Java and Ruby to demonstrate that the Windows Azure Platform is not just about .NET. The following is an interesting interview with Rob Blackwell, the R&D director of the partner who implemented the application. UK Interoperability Team Interviews Rob Blackwell, R&D Director at Active Web Solutions. Is Microsoft taking interoperability seriously? Yes. In the past, I think Microsoft has, quite rightly come in for criticism, but architects and developers should look at this again. The Interoperability Bridges site (http://www.interoperabilitybridges.com/ ) shows a wide range of projects that allow interoperability from Java, Ruby and PHP for example. The Windows Azure platform has been architected with interoperable APIs in mind. It's straightforward to access the various storage facilities from just about any language or platform. Azure compute is capable of running more than just C# applications! Why is interoperability important to you? My company provides consultancy and bespoke development services. We're a Microsoft Gold Partner, but we live in the real world where companies have a mix of technologies provided by a variety of vendors. When developing an enterprise software solution, you rarely have a completely blank canvas. We often see integration scenarios where we need to exchange data with legacy systems. It's not unusual to see modern Silverlight applications being built on top of Java or Mainframe based back ends. Could you give us some examples of where interoperability has been important for your projects? We developed an innovative Sea Safety system for the RNLI Lifeboats here in the UK. Commercial Fishing is one of the most dangerous professions and we helped developed the MOB Guardian System which uses satellite technology and man overboard devices to raise the alarm when a fisherman gets into trouble. The solution is implemented in .NET running on Windows, but without interoperable standards, it would have been impossible to communicate with the satellite gateway technology. For more information, please see the case study: http://www.microsoft.com/casestudies/Case_Study_Detail.aspx?CaseStudyID=4000005892 More recently, we were asked to build a web site to accompany the QCon 2010 conference in London to help demonstrate and promote interoperability. We built the site using Java and Restlet and hosted it in Windows Azure Compute. The site accepts feedback from visitors and all the data is stored in Windows Azure Storage. We also ported the application to Ruby on Rails for demonstration purposes. Visitors to the stand were surprised that this was even possible. Why should Java developers be interested in Windows Azure? Windows Azure Storage consists of Blobs, Queues and Tables. The storage is scalable, durable, secure and cost-effective. Using the WindowsAzure4j library, it's easy to use, and takes just a few lines of code. If you are writing an application with large data storage requirements, or you want an offsite backup, it makes a lot of sense. Running Java applications in Azure Compute is straightforward with tools like the Tomcat Solution Accelerator (http://code.msdn.microsoft.com/winazuretomcat )and AzureRunMe (http://azurerunme.codeplex.com/ ). The Windows Azure AppFabric Service Bus can also be used to connect heterogeneous systems running on different networks and in different data centres. How can The Service Bus be considered an interoperability solution? I think that the Windows Azure AppFabric Service Bus is one of Microsoft’s best kept secrets. Think of it as “a globally scalable application plumbing kit in the sky”. If you have used Enterprise Service Buses before, you’ll be familiar with the concept. Applications can connect to the service bus to securely exchange data – these can be point to point or multicast links. With the AppFabric Service Bus, the applications can exist anywhere that has access to the Internet and the connections can traverse firewalls. This makes it easy to extend or scale your application or reach out to other networks and technologies. For example, let’s say you have a SQL Server database running on premises and you want to expose the data to a Java application running in the cloud. You could set up a point to point Service Bus connection and use JDBC. Traditionally this would have been difficult or impossible without punching holes in firewalls and compromising security. Rob Blackwell is R&D Director at Active Web Solutions, www.aws.net , a Microsoft Gold Partner specialising in leading edge software solutions. He is an occasional writer and conference speaker and blogs at www.robblackwell.org.uk Related Links: UK Azure Online Community – join today. UK Windows Azure Site Start working with Windows Azure

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• SQL SERVER – 4 Tips for ETL Software IDE Developers

  - by pinaldave

  In a previous blog, I introduced the notion of Semantic Types. To an end-user, a seamlessly integrated semantic typing engine significantly increases the ease of use of an ETL IDE (integrated development environment, or developer studio). This led me to think about other ease-of-use issues I have encountered while building ETL applications. When I get stumped while programming, I find myself asking the variations on these questions: “How do I…?” “Now what?” “Why isn’t this working?” “Why do I have to redo the work I just did?” It seems to me that a good ETL IDE will anticipate these questions and seek to answer them before they are even asked. So here are my tips to help software vendors build developer IDEs that actually make development easier. How do I…? While developing an ETL application, have you ever asked yourself: “How do I set up the connection to my SQL Server database?”,“How do I import my table definitions from Access?”, etc. An easy answer might be “read the manual” but sometimes product manuals are not robust or easily accessible. So, integrating robust how-to instructions directly into your ETLstudio would help users get the information they need at the time they need it. Now what? IDEs in general know where you last clicked or performed an action using an input device such as a keyboard; so they should be able to reasonably predict the design context you are in and suggest the next steps accordingly. Context-sensitive suggestions based on the state of the user’s work will help users move forward in ETL application development. Why isn’t this working? Or why do I have to wait till I compile to be told about a critical design issue? If an ETL IDE is smart enough to signal to users what in their design structures is left to be completed or has been completed incorrectly, then the developer can spend much less time in the designàcompileàerror-correct loop. Just-in-time validation helps users detect and correct programming errors earlier in the ETL development life cycle. Why do I have to redo the work I just did? In ETL development, schemas, transformation rules, connectivity objects, etc., can be reused in various situations. Using mouse-clicks to build and manage libraries of reusable design objects implies that the application development effort should decrease over time and as the library acquires more objects. I met a great company at SQL Pass that is trying to address many of these usability issues. Check them out at www.expressor-software.com. What other ease-of-use suggestions do you have for ETL software vendors? Please post your valuable comments. ?Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: Best Practices, Pinal Dave, PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology Tagged: ETL

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• Unstructured Data - The future of Data Administration

  Some have claimed that there is a problem with the way data is currently managed using the relational paradigm do to the rise of unstructured data in modern business. PCMag.com defines unstructured data as data that does not reside in a fixed location. They further explain that unstructured data refers to data in a free text form that is not bound to any specific structure. With the rise of unstructured data in the form of emails, spread sheets, images and documents the critics have a right to argue that the relational paradigm is not as effective as the object oriented data paradigm in managing this type of data. The relational paradigm relies heavily on structure and relationships in and between items of data. This type of paradigm works best in a relation database management system like Microsoft SQL, MySQL, and Oracle because data is forced to conform to a structure in the form of tables and relations can be derived from the existence of one or more tables. These critics also claim that database administrators have not kept up with reality because their primary focus in regards to data administration deals with structured data and the relational paradigm. The relational paradigm was developed in the 1970’s as a way to improve data management when compared to standard flat files. Little has changed since then, and modern database administrators need to know more than just how to handle structured data. That is why critics claim that today’s data professionals do not have the proper skills in order to store and maintain data for modern systems when compared to the skills of system designers, programmers , software engineers, and data designers  due to the industry trend of object oriented design and development. I think that they are wrong. I do not disagree that the industry is moving toward an object oriented approach to development with the potential to use more of an object oriented approach to data.   However, I think that it is business itself that is limiting database administrators from changing how data is stored because of the potential costs, and impact that might occur by altering any part of stored data. Furthermore, database administrators like all technology workers constantly are trying to improve their technical skills in order to excel in their job, so I think that accusing data professional is not just when the root cause of the lack of innovation is controlled by business, and it is business that will suffer for their inability to keep up with technology. One way for database professionals to better prepare for the future of database management is start working with data in the form of objects and so that they can extract data from the objects so that the stored information within objects can be used in relation to the data stored in a using the relational paradigm. Furthermore, I think the use of pattern matching will increase with the increased use of unstructured data because object can be selected, filtered and altered based on the existence of a pattern found within an object.

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• Upgrading 13.04 to 13.10, could not calculate the upgrade

  - by topless

  I am running sudo update-manager -d and start the upgrade process. I select upgrade option and when then manager enters Setting new software channels it throws an error. Could not calculate the upgrade An unresolvable problem occurred while calculating the upgrade. This can be caused by: * Upgrading to a pre-release version of Ubuntu * Running the current pre-release version of Ubuntu * Unofficial software packages not provided by Ubuntu If none of this applies, then please report this bug using the command 'ubuntu-bug ubuntu-release-upgrader-core' in a terminal. I have disabled all unofficial and third party packages, I am not running a pre-release version since I am at 13.04 and I am trying to update to beta 2 which is not a pre-release. Before I fill a bug report, since its happening to both of my systems I would like to figure out if anyone else had same issues.

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• What Functional features are worth a little OOP confusion for the benefits they bring?

  - by bonomo

  After learning functional programming in Haskell and F#, the OOP paradigm seems ass-backwards with classes, interfaces, objects. Which aspects of FP can I bring to work that my co-workers can understand? Are any FP styles worth talking to my boss about retraining my team so that we can use them? Possible aspects of FP: Immutability Partial Application and Currying First Class Functions (function pointers / Functional Objects / Strategy Pattern) Lazy Evaluation (and Monads) Pure Functions (no side effects) Expressions (vs. Statements - each line of code produces a value instead of, or in addition to causing side effects) Recursion Pattern Matching Is it a free-for-all where we can do whatever the programming language supports to the limit that language supports it? Or is there a better guideline?

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• Oracle Coherence & Oracle Service Bus: REST API Integration

  - by Nino Guarnacci

  This post aims to highlight one of the features found in Oracle Coherence which allows it to be easily added and integrated inside a wider variety of projects.  The features in question are the REST API exposed by the Coherence nodes, with which you can interact in the wider mode in memory data grid.Oracle Coherence and Oracle Service Bus are natively integrated through a feature found in the Oracle Service Bus, which allows you to use the coherence grid cache during the configuration phase of a business service. This feature allows you to use an intermediate layer of cache to retrieve the answers from previous invocations of the same service, without necessarily having to invoke the real business service again. Directly from the web console of Oracle Service Bus, you can decide the policies of eviction of the objects / answers and define the discriminating parameters that identify their uniqueness.The coherence REST APIs, however, allow you to integrate both products for other necessities enabling realization of new architectures design.  Consider coherence’s node as a simple service which interoperates through the stardard services and in particular REST (with JSON and XML). Thinking of coherence as a company’s shared service, able to have an implementation of a centralized “map and reduce” which you can access  by a huge variety of protocols (transport and envelopes).An amazing step forward for those who still imagine connectors and code. This type of integration does not require writing custom code or complex implementation to be self-supported. The added value is made unique by the incredible value of both products independently, and still more out of their simple and robust integration.As already mentioned this scenario discovers a hidden new door behind the columns of these two products. The door leads to new ideas and perspectives for enterprise architectures that increasingly wink to next-generation applications: simple and dynamic, perhaps towards the mobile and web 2.0.Below, a small and simple demo useful to demonstrate how easily is to integrate these two products using the Coherence REST API. This demo is also intended to imagine new enterprise architectures using this approach.The idea is to create a centralized system of alerting, fed easily from any company’s application, regardless of the technology with which they were built . Then use a representation standard protocol: RSS, using a service exposed by the service bus; So you can browse and search only the alerts that you are interested on, by category, author, title, date, etc etc.. The steps needed to implement this system are very simple and very few. Here they are listed below and described to be easily replicated within your environment. I would remind you that the demo is only meant to demonstrate how easily is to integrate Oracle Coherence and the Oracle Service Bus, and stimulate your imagination to new technological approaches.1) Install the two products: In this demo used (if necessary, consult the installation guides of 2 products)  - Oracle Service Bus ver. 11.1.1.5.0 http://www.oracle.com/technetwork/middleware/service-bus/downloads/index.html - Oracle Coherence ver. 3.7.1 http://www.oracle.com/technetwork/middleware/coherence/downloads/index.html 2) Because you choose to create a centralized alerting system, we need to define a structure type containing some alerting attributes useful to preserve and organize the information of the various alerts sent by the different applications. Here, then it was built a java class named Alert containing the canonical properties of an alarm information:- Title- Description- System- Time- Severity 3) Therefore, we need to create two configuration files for the coherence node, in order to save the Alert objects within the grid, through the rest/http protocol (more than the native API for Java, C + +, C,. Net). Here are the two minimal configuration files for Coherence:coherence-rest-config.xml resty-server-config.xml This minimum configuration allows me to use a distributed cache named "alerts" that can  also be accessed via http - rest on the host "localhost" over port "8080", objects are of type “oracle.cohsb.Alert”. 4) Below  a simple Java class that represents the type of alert messages: 5) At this point we just need to startup our coherence node, able to listen on http protocol to manage the “alerts” cache, which will receive incoming XML or JSON objects of type Alert. Remember to include in the classpath of the coherence node, the Alert java class and the following coherence libraries and configuration files:  At this point, just run the coherence class node “com.tangosol.net.DefaultCacheServer”advising you to set the following parameters:-Dtangosol.coherence.log.level=9 -Dtangosol.coherence.log=stdout -Dtangosol.coherence.cacheconfig=[PATH_TO_THE_FILE]\resty-server-config.xml 6) Let's create a procedure to test our configuration of Coherence and in order to insert some custom alerts in our cache. The technology with which you want to achieve this functionality is fully not considerable: Javascript, Python, Ruby, Scala, C + +, Java.... Because the protocol to communicate with Coherence is simply HTTP / JSON or XML. For this little demo i choose Java: A method to send/put the alert to the cache: A method to query and view the content of the cache: Finally the main method that execute our methods:  No special library added in the classpath for our class (json struct static defined), when it will be executed, it asks some information such as title, description,... in order to compose and send an alert to the cache and then it will perform an inquiry, to the same cache. At this point, a good exercise at this point, may be to create the same procedure using other technologies, such as a simple html page containing some JavaScript code, and then using Python, Ruby, and so on.7) Now we are ready to start configuring the Oracle Service Bus in order to integrate the two products. First integrate the internal alerting system of Oracle Service Bus with our centralized alerting system based on coherence node. This ensures that by monitoring, or directly from within our Proxy Message Flow, we can throw alerts and save them directly into the Coherence node. To do this I choose to use the jms technology, natively present inside the Oracle Weblogic / Service Bus. Access to the Oracle WebLogic Administration console and create and configure a new JMS connection factory and a new jms destination (queue). Now we should create a new resource of type “alert destination” within our Oracle Service Bus project. The new “alert destination” resource should be configured using the newly created connection factory jms and jms destination. Finally, in order to withdraw the message alert enqueued in our JMS destination and send it to our coherence node, we just need to create a new business service and proxy service within our Oracle Service Bus project.Our business service is responsible for sending a message to our REST service Coherence using as a method action: PUT Finally our proxy service have to collect all messages enqueued on the destination, execute an xquery transformation on those messages  in order to translate them into valid XML / alert objects useful to be sent to our coherence service, through the newly created business service. The message flow pipeline containing the xquery transformation: Incredibly,  we just did a basic first integration between the native alerting system of Oracle Service Bus and our centralized alerting system by simply configuring our coherence node without developing anything.It's time to test it out. To do this I create a proxy service able to generate an alert using our "alert destination", whenever the proxy is invoked. After some invocation to our proxy that generates fake alerts, we could open an Internet browser and type the URL  http://localhost: 8080/alerts/  so we could see what has been inserted within the coherence node. 8) We are ready for the final step.  We would create a new message flow, that can be used to search and display the results in standard mode. To do this I choosen the standard representation of RSS, to display a formatted result on a huge variety of devices such as readers for the iPhone and Android. The inquiry may be defined already at the time of the request able to return only feed / items related to our needs. To do this we need to create a new business service, a new proxy service, and finally a new XQuery Transformation to take care of translating the collection of alerts that will be return from our coherence node in a nicely formatted RSS standard document.So we start right from this resource (xquery), which has the task of transforming a collection of alerts / xml returned from the node coherence in a type well-formatted feed RSS 2.0 our new business service that will search the alerts on our coherence node using the Rest API. And finally, our last resource, the proxy service that will be exposed as an RSS / feeds to various mobile devices and traditional web readers, in which we will intercept any search query, and transform the result returned by the business service in an RSS feed 2.0. The message flow with the transformation phase (Alert TO Feed Items): Finally some little tricks to follow during the routing to the business service, - check for any queries present in the url to require a subset of alerts  - the http header "Accept" to help get an answer XML instead of JSON: In our little demo we also static added some coherence parameters to the request:sort=time:desc;start=0;count=100I would like to get from Coherence that the results will be sorted by date, and starting from 1 up to a maximum of 100.Done!!Just incredible, our centralized alerting system is ready. Inheriting all the qualities and capabilities of the two products involved Oracle Coherence & Oracle Service Bus: - RASP (Reliability, Availability, Scalability, Performance)Now try to use your mobile device, or a normal Internet browser by accessing the RSS just published: Some urls you may test: Search for the last 100 alerts : http://localhost:7001/alarmsSearch for alerts that do not have time set to null (time is not null):http://localhost:7001/alarms?q=time+is+not+nullSearch for alerts that the system property is “Web Browser” (system = ‘Web Browser’):http://localhost:7001/alarms?q=system+%3D+%27Web+Browser%27Search for alerts that the system property is “Web Browser” and the severity property is “Fatal” and the title property contain the word “Javascript”  (system = ‘Web Broser’ and severity = ‘Fatal’ and title like ‘%Javascript%’)http://localhost:8080/alerts?q=system+%3D+%27Web+Browser%27+AND+severity+%3D+%27Fatal%27+AND+title+LIKE+%27%25Javascript%25%27 To compose more complex queries about your need I would suggest you to read the chapter in the coherence documentation inherent the Cohl language (Coherence Query Language) http://download.oracle.com/docs/cd/E24290_01/coh.371/e22837/api_cq.htm . Some useful links: - Oracle Coherence REST API Documentation http://download.oracle.com/docs/cd/E24290_01/coh.371/e22839/rest_intro.htm - Oracle Service Bus Documentation http://download.oracle.com/docs/cd/E21764_01/soa.htm#osb - REST explanation from Wikipedia http://en.wikipedia.org/wiki/Representational_state_transfer At this URL could be downloaded the whole materials of this demo http://blogs.oracle.com/slc/resource/cosb/coh-sb-demo.zip Author: Nino Guarnacci.

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• OpenGL ES 2.0: Using VBOs?

  - by Bunkai.Satori

  OpenGL VBOs (vertex buffer objects) have been developed to improve performance of OpenGL (OpenGL ES 2.0 in my case). The logic is that with the help of VBOs, the data does not need to be copied from client memory to graphics card on per frame basis. However, as I see it, the game scene changes continuously: position of objects change, their scaling and rotating change, they get animated, they explode, they get spawn or disappear. In such highly dynamic environment, such as computer game scene is, what is the point of using VBOs, if the VBOs would need to be constructed on per-frame basis anyway? Can you please help me to understand how to practically take beneif of VBOs in computer games? Can there be more vertex based VBOs (say one per one object) or there must be always exactly only one VBO present for each draw cycle?

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• Replication Services in a BI environment

  - by jorg

  In this blog post I will explain the principles of SQL Server Replication Services without too much detail and I will take a look on the BI capabilities that Replication Services could offer in my opinion. SQL Server Replication Services provides tools to copy and distribute database objects from one database system to another and maintain consistency afterwards. These tools basically copy or synchronize data with little or no transformations, they do not offer capabilities to transform data or apply business rules, like ETL tools do. The only “transformations” Replication Services offers is to filter records or columns out of your data set. You can achieve this by selecting the desired columns of a table and/or by using WHERE statements like this: SELECT <published_columns> FROM [Table] WHERE [DateTime] >= getdate() - 60 There are three types of replication: Transactional Replication This type replicates data on a transactional level. The Log Reader Agent reads directly on the transaction log of the source database (Publisher) and clones the transactions to the Distribution Database (Distributor), this database acts as a queue for the destination database (Subscriber). Next, the Distribution Agent moves the cloned transactions that are stored in the Distribution Database to the Subscriber. The Distribution Agent can either run at scheduled intervals or continuously which offers near real-time replication of data! So for example when a user executes an UPDATE statement on one or multiple records in the publisher database, this transaction (not the data itself) is copied to the distribution database and is then also executed on the subscriber. When the Distribution Agent is set to run continuously this process runs all the time and transactions on the publisher are replicated in small batches (near real-time), when it runs on scheduled intervals it executes larger batches of transactions, but the idea is the same. Snapshot Replication This type of replication makes an initial copy of database objects that need to be replicated, this includes the schemas and the data itself. All types of replication must start with a snapshot of the database objects from the Publisher to initialize the Subscriber. Transactional replication need an initial snapshot of the replicated publisher tables/objects to run its cloned transactions on and maintain consistency. The Snapshot Agent copies the schemas of the tables that will be replicated to files that will be stored in the Snapshot Folder which is a normal folder on the file system. When all the schemas are ready, the data itself will be copied from the Publisher to the snapshot folder. The snapshot is generated as a set of bulk copy program (BCP) files. Next, the Distribution Agent moves the snapshot to the Subscriber, if necessary it applies schema changes first and copies the data itself afterwards. The application of schema changes to the Subscriber is a nice feature, when you change the schema of the Publisher with, for example, an ALTER TABLE statement, that change is propagated by default to the Subscriber(s). Merge Replication Merge replication is typically used in server-to-client environments, for example when subscribers need to receive data, make changes offline, and later synchronize changes with the Publisher and other Subscribers, like with mobile devices that need to synchronize one in a while. Because I don’t really see BI capabilities here, I will not explain this type of replication any further. Replication Services in a BI environment Transactional Replication can be very useful in BI environments. In my opinion you never want to see users to run custom (SSRS) reports or PowerPivot solutions directly on your production database, it can slow down the system and can cause deadlocks in the database which can cause errors. Transactional Replication can offer a read-only, near real-time database for reporting purposes with minimal overhead on the source system. Snapshot Replication can also be useful in BI environments, if you don’t need a near real-time copy of the database, you can choose to use this form of replication. Next to an alternative for Transactional Replication it can be used to stage data so it can be transformed and moved into the data warehousing environment afterwards. In many solutions I have seen developers create multiple SSIS packages that simply copies data from one or more source systems to a staging database that figures as source for the ETL process. The creation of these packages takes a lot of (boring) time, while Replication Services can do the same in minutes. It is possible to filter out columns and/or records and it can even apply schema changes automatically so I think it offers enough features here. I don’t know how the performance will be and if it really works as good for this purpose as I expect, but I want to try this out soon!

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• No Wi-Fi after system reboot

  - by ILya

  Something strange is happening... I've installed a Wi-Fi card into my Ubuntu Server 11.04 machine. To configure it I do the following: sudo vi /etc/network/interfaces add: iface wlan0 inet dhcp wpa-driver wext wpa-ssid "Sweet Home" wpa-ap-scan 1 wpa-proto WPA wpa-pairwise TKIP wpa-group TKIP wpa-key-mgmt WPA-PSK wpa-psk <A KEY> auto wlan0 then: $ sudo /etc/init.d/networking restart * Running /etc/init.d/networking restart is deprecated because it may not enable again some interfaces * Reconfiguring network interfaces... ssh stop/waiting ssh start/running, process 1522 ssh stop/waiting ssh start/running, process 1590 And my machine successfully gets an ip to my wireless adapter. But after reboot it doesn't get any ip in wireless network. To fix it I run /etc/init.d/networking restart again and all is fine again - it gets an ip. I understand that I simply should add it to my startup scripts to make it work properly, but maybe there is a better way to configure it?

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• Rotate to a set degree then reverse and repeat in Unity

  - by Ryan

  and thank you for your time. I'm making my first project in Unity, a simple game where touching objects adds points to the players score. I'd like the objects to have a pleasant back and forth swaying animation on the Z axis. Nodding to the right 30 degrees, then to the left 30 degrees, on and on. Here's what I've got... public class Rotator : MonoBehaviour { void Update () { transform.Rotate(new Vector3(0,0,12)*Time.deltaTime); } } This gives me a nice slow rotation. But I am clueless how to tell Unity to stop at +30 degrees, reverse to -30 degrees, rotate again to +30, stop and repeat, etc, etc. I'd really appreciate any help. Maybe there is a thread like this that I was not able to find? I assume it will involve some kind of 'if than' function? Thank you, Ryan

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• Simultaneously calling multiple methods on a WCF service from silverlight

  - by ola karlsson

  A while back I had to debug some performance issues in an existing Silverlight app, as the problem / solution was a bit obscure and finding info about it was quite tricky, I thought I’d share, maybe it can help the next person with this problem. The App On start, the app would do a number of calls to different methods on a WCF service, this to populate the UI with the necessary data. Recently one of those services had been changed and was now taking quite a bit longer than it used to. This was resulting in quite a long loading time for the whole UI, which was set up so it wouldn’t let the user interact with anything, until all the service calls had finished. First I broke out the longer running service call from the others, then removed the constraint that it had to be loaded for the UI in general to become responsive. I also added a loading indicator just on that area of the UI, thinking that the main UI would load while this particular section could keep loading independently. The Problem However this is where things started to get a bit strange. I found that even after these changes, the main UI wouldn’t activate until the long running call returned. So now, I did what I should have done to start with, I got Fiddler out and had a look at what was really happening. What I found was that, once the call to the long running service method was placed, all subsequent call were waiting for that one to return before executing. Not having really worked with WCF previously or knowing much about it in general, I was stumped… I knew of the issues where Silverlight is restricted by the browsers networking features in regards to number of simultaneous connections etc. However that just didn’t seem to be the issue here, you can clearly see in Fiddler that there’s numerous calls, but they’re just not returning. I thought of the problem maybe being in the WCF service, but the calls were really not that complicated and surely the service should be able to handle a lot more than what I was throwing at it! So I did what every developer does in this type of scenario, I hit the search engines. I did a whole bunch of searching on things like “multiple simultaneous WCF calls from Silverlight” and “Calling long running WCF services from Silverlight” etc. etc. This however, pretty much got me nowhere, I found a whole heap of resources on how to do WCF calls from Silverlight but most of them were very basic and of no use what so ever. The fog is clearing It wasn’t until I came across the term “ WCF blocking calls” and started incorporating that in my searches I started to get somewhere. Those searches quite quickly brought me to the following thread in the Silverlight forum “Long-running WCF call blocking subsequent calls” which discussed the exact problem I was facing and the best part, one of the guys there had the solution! The short answer is in the forum post and the guys answering, has also done a more extensive blog post about it called “Silverlight, WCF, and ASP.Net Configuration Gotchas” which covers it very well.  So come on what’s the solution?! I heard you ask, unless you’ve already gone to the links and looked it up ;) The Solution Well, it turns out that the issue is founded in a mix of Silverlight, Asp.Net and WCF, basically if you’re doing multiple calls to a single WCF web-service and you have Asp.Net session state enabled, the calls will be executed sequentially by the service, hence any long running calls will block subsequent ones. So why is Asp.Net session state effecting us, we’re working in Silverlight, right? We'll as mentioned earlier, by default Silverlight uses the browsers networking stack when doing service calls, hence to the WCF service, the call looks like it might as well be coming from a normal Asp.Net. To get around this, we look to a feature introduced in Silverlight 3, namely the Client HTTP Stack. The Client HTTP Stack to the rescue By using the following syntax (for example in our App.xaml.cs, Application_Startup method) WebRequest.RegisterPrefix("http://", WebRequestCreator.ClientHttp); we can set our Silverlight application to use the Client HTTP Stack, which incidentally solves our problem! By using Silverlights own networking stack, rather than that of the browser, we get around the Asp.Net - WCF session state issue. The above code specifies that all calls to addresses starting with “http://” should go through the client stack, this can actually be set more granular and you can specify it to be used only for certain domains etc. Summary The actual solution is well covered in the forum and blog posts I link to above. This post is more about sharing my experience, hopefully helping to spread the word about this and maybe make it a bit easier for the next poor guy with this issue to find the solution. Until next time, Ola

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• Enable remote VNC from the commandline?

  - by Stefan Lasiewski

  I have one computer running Ubuntu 10.04, and is running Vino, the default VNC server. I have a second Windows box which is running a VNC client, but does not have any X11 capabilities. I am ssh'd into the Ubuntu host from the Windows host, but I forgot to enable VNC access on the Ubuntu host. On the Ubuntu host, is there a way for me to enable VNC connections from the Ubuntu commandline? Update: As @koanhead says below, there is no man page for vino (e.g. man -k vino and info vino return nothing), and vino --help doesn't show any help).

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• How to Automate your Database Documentation

  - by Jonathan Hickford

  In my previous post, “Automating Deployments with SQL Compare command line” I looked at how teams can automate the deployment and post deployment validation of SQL Server databases using the command line versions of Red Gate tools. In this post I’m looking at another use for the command line tools, namely using them to generate up-to-date documentation with every database change. There are many reasons why up-to-date documentation is valuable. For example when somebody new has to work on or administer a database for the first time, or when a new database comes into service. Having database documentation reduces the risks of making incorrect decisions when making changes. Documentation is very useful to business intelligence analysts when writing reports, for example in SSRS. There are a couple of great examples talking about why up to date documentation is valuable on this site:  Database Documentation – Lands of Trolls: Why and How? and Database Documentation Using SQL Doc. The short answer is that it can save you time and reduce risk when you need that most! SQL Doc is a fast simple tool that automatically generates database documentation. It can create documents in HTML, Word or pdf files. The documentation contains information about object definitions and dependencies, along with any other information you want to associate with each object. The SQL Doc GUI, which is included in Red Gate’s SQL Developer Bundle and SQL Toolbelt, allows you to add additional notes to objects, and customise which objects are shown in the docs.  These settings can be saved as a .sqldoc project file. The SQL Doc command line can use this project file to automatically update the documentation every time the database is changed, ensuring that documentation that is always up to date. The simplest way to keep documentation up to date is probably to use a scheduled task to run a script every day. However if you have a source controlled database, or are using a Continuous Integration (CI) server or a build server, it may make more sense to use that instead. If  you’re using SQL Source Control or SSDT Database Projects to help version control your database, you can automatically update the documentation after each change is made to the source control repository that contains your database. To get this automation in place,  you can use the functionality of a Continuous Integration (CI) server, which can trigger commands to run when a source control repository has changed. A CI server will also capture and save the documentation that is created as an artifact, so you can always find the exact documentation for a specific version of the database. This forms an always up to date data dictionary. If you don’t already have a CI server in place there are several you can use, such as the free open source Jenkins or the free starter editions of TeamCity. I won’t cover setting these up in this article, but there is information about using CI servers for automating database tasks on the Red Gate Database Delivery webpage. You may be interested in Red Gate’s SQL CI utility (part of the SQL Automation Pack) which is an easy way to update a database with the latest changes from source control. The PowerShell example below shows how to create the documentation from a database. That database might be your integration database or a shared development database that is always up to date with the latest changes. $serverName = "server\instance" $databaseName = "databaseName" # If you want to document multiple databases use a comma separated list $userName = "username" $password = "password" # Path to SQLDoc.exe $SQLDocPath = "C:\Program Files (x86)\Red Gate\SQL Doc 3\SQLDoc.exe" $arguments = @( "/server:$($serverName)", "/database:$($databaseName)", "/username:$($userName)", "/password:$($password)", "/filetype:html", "/outputfolder:.", # "/project:$args[0]", # If you already have a .sqldoc project file you can pass it as an argument to this script. Values in the project will be overridden with any options set on the command line "/name:$databaseName Report", "/copyrightauthor:$([Environment]::UserName)" ) write-host $arguments & $SQLDocPath $arguments There are several options you can set on the command line to vary how your documentation is created. For example, you can document multiple databases or exclude certain types of objects. In the example above, we set the name of the report to match the database name, and use the current Windows user as the documentation author. For more examples of how you can customise the report from the command line please see the SQL Doc command line documentation If you already have a .sqldoc project file, or wish to further customise the report by including or excluding specific objects, you can use this project on the command line. Any settings you specify on the command line will override the defaults in the project. For details of what you can customise in the project please see the SQL Doc project documentation. In the example above, the line to use a project is commented out, but you can uncomment this line and then pass a path to a .sqldoc project file as an argument to this script.  Conclusion Keeping documentation about your databases up to date is very easy to set up using SQL Doc and PowerShell. By using a CI server to run this process you can trigger the documentation to be run on every change to a source controlled database, and keep historic documentation available. If you are considering more advanced database automation, e.g. database unit testing, change script generation, deploying to large numbers of targets and backup/verification, please email me at [email protected] for further script samples or if you have any questions.

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• Shell script issue: cron job script to Restart MySQL server when it stops accidentally

  - by Straw Hat

  I have this script, I am using it to setup CRON job to execute this script, so it can check if MySQL service is running; if not then it restart the MySQL service: #!/bin/bash service mysql status| grep 'mysql start/running' > /dev/null 2>&1 if [ $? != 0 ] then sudo service mysql restart fi I have setup cron job as. sudo crontab -e and then added, */1 * * * * /home/ubuntu/mysql-check.sh Problem is that it restart MySQL on every cron job execution.. even if server is running it restart the MySQL service what is correction in the script to do that.

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• Using Tree(Map,Set) in Collections

  To add objects to a Tree(Map, Set), implement the Comparable.compareTo method.

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• Using Tree(Map,Set) in Collections

  To add objects to a Tree(Map, Set), implement the Comparable.compareTo method.

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• Backup Azure Tables, schedule Azure scripts&hellip; and more

  - by Herve Roggero

  Well – months of effort are now officially over… or should I say it’s just the beginning?   Enzo Cloud Backup 2.0 (beta) is now officially out!!! This tool will let you do the following: * Backup SQL Database (and SQL Server to a limited extend) * Backup Azure Tables * Restore SQL Backups into another SQL environment * Restore Azure Tables in Azure Storage, or SQL Environment * Manage and schedule database maintenance scripts * Drop database schema containers (with preview) for SaaS environments * Receive alerts (SMTP) when operations complete or fail That’s it at a high level… but you need to see the flexibility around these features. For example you can select a specific backup strategy for Azure Tables allowing faster backup operations when partition keys use GUIDs. You can also call custom stored procedures during the restore operation of Azure Tables, allowing you to transform the data along the way. You can also set a performance threshold during Azure Table backup operations to help you control possible throttling conditions in your Storage Account. Regarding database scripts, you can now define T-SQL scripts and schedule them for execution in a specific order. You can also tell Enzo to execute a pre and post script during Azure Table restore operations against a SQL environment. The backup operation now supports backing up to multiple devices at the same time. So you can execute a backup request to both a local file, and a blob at the same time, guaranteeing that both will contain the exact same data. And due to the level of options that are available, you can save backup definitions for later reuse. The screenshot below backs up Azure Tables to two devices (a blob and a SQL Database). You can also manage your database schemas for SaaS environments that use schema containers to separate customer data. This new edition allows you to see how many objects you have in each schema, backup specific schemas, and even drop all objects in a given schema. For example the screenshot below shows that the EnzoLog database has 4 user-defined schemas, and the AFA schema has 5 tables and 1 module (stored proc, function, view…). Selecting the AFA schema and trying to delete it will prompt another screen to show which objects will be deleted. As you can see, Enzo Cloud Backup provides amazing capabilities that can help you safeguard your data in SQL Database and Azure Tables, and give you advanced management functions for your Azure environment. Download a free trial today at http://www.bluesyntax.net.

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• Ubuntu 12.04 transmission-daemon and zfsonlinux: bad file descriptor and corrupt pieces

  - by Ivailo Karamanolev

  I'm running a Ubuntu 12.04 with zfsonlinux and transmission-daemon. The issues: sporadic Bad File Descriptor and Piece #xxx is corrupt errors. After I recheck the torrent, everything seems fine. That happens only when downloading: once it's in seeding mode. This only happens after the torrent client has been running for some time. I installed zfsonlinux from the offical stable ppa (https://launchpad.net/~zfs-native/+archive/stable). I previously tried running transmission-daemon from the Ubuntu repository, but since I've switched to building the latest transmission from source with the latest libevent (all stable) - same thing. I've seen bug reports (https://trac.transmissionbt.com/ticket/4147) for that issue, but none of them seem to have a solution. How can I fix these errors, or at least understand where they come from and what I can do to rectify the issue?

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• Item 2, Scott Myers Effective C++ question

  - by user619818

  In Item2 on page 16, (Prefer consts, enums, and inlines to #defines), Scott says: 'Also, though good compilers won't set aside storage for const objects of integer types'. I don't understand this. If I define a const object, eg const int myval = 5; then surely the compiler must set aside some memory (of int size) to store the value 5? Or is const data stored in some special way? This is more a question of computer storage I suppose. Basically, how does the computer store const objects so that no storage is set aside?

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• setting up mod_proxy - plesk, apache, .htacess?

  - by sam

  I want to set up mod_proxy to work so that my blog is running under a subdirectory of my site rather than subdomain so i get the seo backlink benefit. What im looking to do is get my tumblr blog which is running at blog.mysite.com (which is in turn mapped from myblog.tumblr.com) will be running on mysite.com/blog How can i set up mod_proxy to do this, is it just something that i can setup from inside of my .htacess file ? Ive got my site hosted on an apache server, using plesk as a controll panel. I contacted my webhost and they told me mod_rewrite could acheve it, they gave me this but said they wont provide me further support regarding mod_rewrite as its somthing they dont support <IfModule mod_rewrite.c> RewriteEngine On RewriteCond %{HTTP_HOST} ^example.co.uk/blog$ RewriteCond %{REQUEST_URI} !/standard RewriteRule ^(.*)$ http://example.tumblr.com$1 [R] </IfModule> ideally id like to use the mod_proxy method as it recomended from an seo point of view from this article http://www.seomoz.org/blog/what-is-a-reverse-proxy-and-how-can-it-help-my-seo

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• How to implement Undo and Redo feature in as3

  - by Swati Singh

  I am going to create an application in that i have to implement an Undo and Redo feature. In the application there will be multiple objects located on stage and user can customize the position of the objects. But when user clicks on Undo the object go back to their default position and after clicking on redo object will move on the new position. So my question is how can i apply these feature in my application? Is there any library or any third party classes? Can some one help me? Thanks in advance.

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• teamviewer in "client only" mode

  - by Tommy

  I have a remote PC with the teamviewer on it. I want to use my local teamviewer installation only for connecting to that remote PC, and I don't want any services (teamviewerd) running on my local Ubuntu 14.04. I've tried to disable the service by doing sudo teamviewer --daemon disable but after that I'm not able to connect to the remote PC, because teamviewer reports an error "The Teamviewer daemon is not running!" on start, and I'm not able to access the gui. Is there a way to connect to the remote PC with teamviewer with no teamviewerd running?

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• Liskov Substitution Principle and the Oft Forgot Third Wheel

  - by Stacy Vicknair

  Liskov Substitution Principle (LSP) is a principle of object oriented programming that many might be familiar with from the SOLID principles mnemonic from Uncle Bob Martin. The principle highlights the relationship between a type and its subtypes, and, according to Wikipedia, is defined by Barbara Liskov and Jeanette Wing as the following principle:   Let be a property provable about objects of type . Then should be provable for objects of type where is a subtype of .   Rectangles gonna rectangulate The iconic example of this principle is illustrated with the relationship between a rectangle and a square. Let’s say we have a class named Rectangle that had a property to set width and a property to set its height. 1: Public Class Rectangle 2: Overridable Property Width As Integer 3: Overridable Property Height As Integer 4: End Class   We all at some point here that inheritance mocks an “IS A” relationship, and by gosh we all know square IS A rectangle. So let’s make a square class that inherits from rectangle. However, squares do maintain the same length on every side, so let’s override and add that behavior. 1: Public Class Square 2: Inherits Rectangle 3:  4: Private _sideLength As Integer 5:  6: Public Overrides Property Width As Integer 7: Get 8: Return _sideLength 9: End Get 10: Set(value As Integer) 11: _sideLength = value 12: End Set 13: End Property 14:  15: Public Overrides Property Height As Integer 16: Get 17: Return _sideLength 18: End Get 19: Set(value As Integer) 20: _sideLength = value 21: End Set 22: End Property 23: End Class   Now, say we had the following test: 1: Public Sub SetHeight_DoesNotAffectWidth(rectangle As Rectangle) 2: 'arrange 3: Dim expectedWidth = 4 4: rectangle.Width = 4 5:  6: 'act 7: rectangle.Height = 7 8:  9: 'assert 10: Assert.AreEqual(expectedWidth, rectangle.Width) 11: End Sub   If we pass in a rectangle, this test passes just fine. What if we pass in a square?   This is where we see the violation of Liskov’s Principle! A square might "IS A” to a rectangle, but we have differing expectations on how a rectangle should function than how a square should! Great expectations Here’s where we pat ourselves on the back and take a victory lap around the office and tell everyone about how we understand LSP like a boss. And all is good… until we start trying to apply it to our work. If I can’t even change functionality on a simple setter without breaking the expectations on a parent class, what can I do with subtyping? Did Liskov just tell me to never touch subtyping again? The short answer: NO, SHE DIDN’T. When I first learned LSP, and from those I’ve talked with as well, I overlooked a very important but not appropriately stressed quality of the principle: our expectations. Our inclination is to want a logical catch-all, where we can easily apply this principle and wipe our hands, drop the mic and exit stage left. That’s not the case because in every different programming scenario, our expectations of the parent class or type will be different. We have to set reasonable expectations on the behaviors that we expect out of the parent, then make sure that those expectations are met by the child. Any expectations not explicitly expected of the parent aren’t expected of the child either, and don’t register as a violation of LSP that prevents implementation. You can see the flexibility mentioned in the Wikipedia article itself: A typical example that violates LSP is a Square class that derives from a Rectangle class, assuming getter and setter methods exist for both width and height. The Square class always assumes that the width is equal with the height. If a Square object is used in a context where a Rectangle is expected, unexpected behavior may occur because the dimensions of a Square cannot (or rather should not) be modified independently. This problem cannot be easily fixed: if we can modify the setter methods in the Square class so that they preserve the Square invariant (i.e., keep the dimensions equal), then these methods will weaken (violate) the postconditions for the Rectangle setters, which state that dimensions can be modified independently. Violations of LSP, like this one, may or may not be a problem in practice, depending on the postconditions or invariants that are actually expected by the code that uses classes violating LSP. Mutability is a key issue here. If Square and Rectangle had only getter methods (i.e., they were immutable objects), then no violation of LSP could occur. What this means is that the above situation with a rectangle and a square can be acceptable if we do not have the expectation for width to leave height unaffected, or vice-versa, in our application. Conclusion – the oft forgot third wheel Liskov Substitution Principle is meant to act as a guidance and warn us against unexpected behaviors. Objects can be stateful and as a result we can end up with unexpected situations if we don’t code carefully. Specifically when subclassing, make sure that the subclass meets the expectations held to its parent. Don’t let LSP think you cannot deviate from the behaviors of the parent, but understand that LSP is meant to highlight the importance of not only the parent and the child class, but also of the expectations WE set for the parent class and the necessity of meeting those expectations in order to help prevent sticky situations.   Code examples, in both VB and C# Technorati Tags: LSV,Liskov Substitution Principle,Uncle Bob,Robert Martin,Barbara Liskov,Liskov

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• openGL migration from SFML to glut, vertices arrays or display lists are not displayed

  - by user3714670

  Due to using quad buffered stereo 3D (which i have not included yet), i need to migrate my openGL program from a SFML window to a glut window. With SFML my vertices and display list were properly displayed, now with glut my window is blank white (or another color depending on the way i clear it). Here is the code to initialise the window : int type; int stereoMode = 0; if ( stereoMode == 0 ) type = GLUT_DOUBLE | GLUT_RGB | GLUT_DEPTH; else type = GLUT_DOUBLE | GLUT_RGB | GLUT_DEPTH | GLUT_STEREO; glutInitDisplayMode(type); int argc = 0; char *argv = ""; glewExperimental = GL_TRUE; glutInit(&argc, &argv); bool fullscreen = false; glutInitWindowSize(width,height); int win = glutCreateWindow(title.c_str()); glutSetWindow(win); assert(win != 0); if ( fullscreen ) { glutFullScreen(); width = glutGet(GLUT_SCREEN_WIDTH); height = glutGet(GLUT_SCREEN_HEIGHT); } GLenum err = glewInit(); if (GLEW_OK != err) { fprintf(stderr, "Error: %s\n", glewGetErrorString(err)); } glutDisplayFunc(loop_function); This is the only code i had to change for now, but here is the code i used with sfml and displayed my objects in the loop, if i change the value of glClearColor, the window's background does change color : glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); glClearColor(255.0f, 255.0f, 255.0f, 0.0f); glLoadIdentity(); sf::Time elapsed_time = clock.getElapsedTime(); clock.restart(); camera->animate(elapsed_time.asMilliseconds()); camera->look(); for (auto i = objects->cbegin(); i != objects->cend(); ++i) (*i)->draw(camera); glutSwapBuffers(); Is there any other changes i should have done switching to glut ? that would be great if someone could enlighten me on the subject. In addition to that, i found out that adding too many objects (that were well handled before with SFML), openGL gives error 1285: out of memory. Maybe this is related. EDIT : Here is the code i use to draw each object, maybe it is the problem : GLuint LightID = glGetUniformLocation(this->shaderProgram, "LightPosition_worldspace"); if(LightID ==-1) cout << "LightID not found ..." << endl; GLuint MaterialAmbientID = glGetUniformLocation(this->shaderProgram, "MaterialAmbient"); if(LightID ==-1) cout << "LightID not found ..." << endl; GLuint MaterialSpecularID = glGetUniformLocation(this->shaderProgram, "MaterialSpecular"); if(LightID ==-1) cout << "LightID not found ..." << endl; glm::vec3 lightPos = glm::vec3(0,150,150); glUniform3f(LightID, lightPos.x, lightPos.y, lightPos.z); glUniform3f(MaterialAmbientID, MaterialAmbient.x, MaterialAmbient.y, MaterialAmbient.z); glUniform3f(MaterialSpecularID, MaterialSpecular.x, MaterialSpecular.y, MaterialSpecular.z); // Get a handle for our "myTextureSampler" uniform GLuint TextureID = glGetUniformLocation(shaderProgram, "myTextureSampler"); if(!TextureID) cout << "TextureID not found ..." << endl; glActiveTexture(GL_TEXTURE0); sf::Texture::bind(texture); glUniform1i(TextureID, 0); // 2nd attribute buffer : UVs GLuint vertexUVID = glGetAttribLocation(shaderProgram, "color"); if(vertexUVID==-1) cout << "vertexUVID not found ..." << endl; glEnableVertexAttribArray(vertexUVID); glBindBuffer(GL_ARRAY_BUFFER, color_array_buffer); glVertexAttribPointer(vertexUVID, 2, GL_FLOAT, GL_FALSE, 0, 0); GLuint vertexNormal_modelspaceID = glGetAttribLocation(shaderProgram, "normal"); if(!vertexNormal_modelspaceID) cout << "vertexNormal_modelspaceID not found ..." << endl; glEnableVertexAttribArray(vertexNormal_modelspaceID); glBindBuffer(GL_ARRAY_BUFFER, normal_array_buffer); glVertexAttribPointer(vertexNormal_modelspaceID, 3, GL_FLOAT, GL_FALSE, 0, 0 ); GLint posAttrib; posAttrib = glGetAttribLocation(shaderProgram, "position"); if(!posAttrib) cout << "posAttrib not found ..." << endl; glEnableVertexAttribArray(posAttrib); glBindBuffer(GL_ARRAY_BUFFER, position_array_buffer); glVertexAttribPointer(posAttrib, 3, GL_FLOAT, GL_FALSE, 0, 0); glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, elements_array_buffer); glDrawElements(GL_TRIANGLES, indices.size(), GL_UNSIGNED_INT, 0); GLuint error; while ((error = glGetError()) != GL_NO_ERROR) { cerr << "OpenGL error: " << error << endl; } disableShaders();

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• Dynamic Memory Allocation and Memory Management

  - by Bunkai.Satori

  In an average game, there are hundreds or maybe thousands of objects in the scene. Is it completely correct to allocate memory for all objects, including gun shots (bullets), dynamically via default new()? Should I create any memory pool for dynamic allocation, or is there no need to bother with this? What if the target platform are mobile devices? Is there a need for a memory manager in a mobile game, please? Thank you. Language Used: C++; Currently developed under Windows, but planned to be ported later.

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