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  • Do you want to be an ALM Consultant?

    - by Martin Hinshelwood
    Northwest Cadence is looking for our next great consultant! At Northwest Cadence, we have created a work environment that emphasizes excellence, integrity, and out-of-the-box thinking.  Our customers have high expectations (rightfully so) and we wouldn’t have it any other way!   Northwest Cadence has some of the most exciting customers I have ever worked with and even though I have only been here just over a month I have already: Provided training/consulting for 3 government departments Created and taught courseware for delivering Scrum to teams within a high profile multinational company Started presenting Microsoft's ALM Engagement Program  So if you are interested in helping companies build better software more efficiently, then.. Enquire at [email protected] Application Lifecycle Management (ALM) Consultant An ALM Consultant with a minimum of 8 years of relevant experience with Application Lifecycle Management, Visual Studio (including Visual Studio Team System) and software design is needed. Must provide thought leadership on best practices for enterprise architecture, understand the Microsoft technology solution stack, and have a thorough understanding of enterprise application integration. The ALM Practice Lead will play a central role in designing and implementing the overall ALM Practice strategy, including creating, updating, and delivering ALM courseware and consultancy engagements. This person will also provide project support, deliverables, and quality solutions on Visual Studio Team System that exceed client expectations. Engagements will vary and will involve providing expert training, consulting, mentoring, formulating technical strategies and policies and acting as a “trusted advisor” to customers and internal teams. Sound sense of business and technical strategy required. Strong interpersonal skills as well as solid strategic thinking are key. The ideal candidate will be capable of envisioning the solution based on the early client requirements, communicating the vision to both technical and business stakeholders, leading teams through implementation, as well as training, mentoring, and hands-on software development. The ideal candidate will demonstrate successful use of both agile and formal software development methods, enterprise application patterns, and effective leadership on prior projects. Job Requirements Minimum Education: Bachelor’s Degree (computer science, engineering, or math preferred). Locale / Travel: The Practice Lead position requires estimated 50% travel, most of which will be in the Continental US (a valid national Passport must be maintained).  This is a full time position and will be based in the Kirkland office. Preferred Education: Master’s Degree in Information Technology or Software Engineering; Premium Microsoft Certifications on .NET (MCSD) or MCPD or relevant experience; Microsoft Certified Trainer (MCT) or relevant experience. Minimum Experience and Skills: 7+ years experience with business information systems integration or custom business application design and development in a professional technology consulting, corporate MIS or software development environment. Essential Duties & Responsibilities: Provide training, consulting, and mentoring to organizations on topics that include Visual Studio Team System and ALM. Create content, including labs and demonstrations, to be delivered as training classes by Northwest Cadence employees. Lead development teams through the complete ALM and/or Visual Studio Team System solution. Be able to communicate in detail how a solution will integrate into the larger technical problem space for large, complex enterprises. Define technical solution requirements. Provide guidance to the customer and project team with respect to technical feasibility, complexity, and level of effort required to deliver a custom solution. Ensure that the solution is designed, developed and deployed in accordance with the agreed upon development work plan. Create and deliver weekly status reports of training and/or consulting progress. Engagement Responsibilities: · Provide a strong desire to provide thought leadership related to technology and to help grow the business. · Work effectively and professionally with employees at all levels of a customer’s organization. · Have strong verbal and written communication skills. · Have effective presentation, organizational and planning skills. · Have effective interpersonal skills and ability to work in a team environment. Enquire at [email protected]

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  • problem with frustum AABB culling in DirectX

    - by Matthew Poole
    Hi, I am currently working on a project with a few friends, and I am trying to get frustum culling working. Every single tutorial or article I go to shows that my math is correct and that this should be working. I thought maybe posting here, somebody would catch something I could not. Thank you. Here are the important code snippets /create the projection matrix void CD3DCamera::SetLens(float fov, float aspect, float nearZ, float farZ) { D3DXMatrixPerspectiveFovLH(&projMat, D3DXToRadian(fov), aspect, nearZ, farZ); } //build the view matrix after changes have been made to camera void CD3DCamera::BuildView() { //keep axes orthoganal D3DXVec3Normalize(&look, &look); //up D3DXVec3Cross(&up, &look, &right); D3DXVec3Normalize(&up, &up); //right D3DXVec3Cross(&right, &up, &look); D3DXVec3Normalize(&right, &right); //fill view matrix float x = -D3DXVec3Dot(&position, &right); float y = -D3DXVec3Dot(&position, &up); float z = -D3DXVec3Dot(&position, &look); viewMat(0,0) = right.x; viewMat(1,0) = right.y; viewMat(2,0) = right.z; viewMat(3,0) = x; viewMat(0,1) = up.x; viewMat(1,1) = up.y; viewMat(2,1) = up.z; viewMat(3,1) = y; viewMat(0,2) = look.x; viewMat(1,2) = look.y; viewMat(2,2) = look.z; viewMat(3,2) = z; viewMat(0,3) = 0.0f; viewMat(1,3) = 0.0f; viewMat(2,3) = 0.0f; viewMat(3,3) = 1.0f; } void CD3DCamera::BuildFrustum() { D3DXMATRIX VP; D3DXMatrixMultiply(&VP, &viewMat, &projMat); D3DXVECTOR4 col0(VP(0,0), VP(1,0), VP(2,0), VP(3,0)); D3DXVECTOR4 col1(VP(0,1), VP(1,1), VP(2,1), VP(3,1)); D3DXVECTOR4 col2(VP(0,2), VP(1,2), VP(2,2), VP(3,2)); D3DXVECTOR4 col3(VP(0,3), VP(1,3), VP(2,3), VP(3,3)); // Planes face inward frustum[0] = (D3DXPLANE)(col2); // near frustum[1] = (D3DXPLANE)(col3 - col2); // far frustum[2] = (D3DXPLANE)(col3 + col0); // left frustum[3] = (D3DXPLANE)(col3 - col0); // right frustum[4] = (D3DXPLANE)(col3 - col1); // top frustum[5] = (D3DXPLANE)(col3 + col1); // bottom // Normalize the frustum for( int i = 0; i < 6; ++i ) D3DXPlaneNormalize( &frustum[i], &frustum[i] ); } bool FrustumCheck(D3DXVECTOR3 max, D3DXVECTOR3 min, const D3DXPLANE* frustum) { // Test assumes frustum planes face inward. D3DXVECTOR3 P; D3DXVECTOR3 Q; bool ret = false; for(int i = 0; i < 6; ++i) { // For each coordinate axis x, y, z... for(int j = 0; j < 3; ++j) { // Make PQ point in the same direction as the plane normal on this axis. if( frustum[i][j] > 0.0f ) { P[j] = min[j]; Q[j] = max[j]; } else { P[j] = max[j]; Q[j] = min[j]; } } if(D3DXPlaneDotCoord(&frustum[i], &Q) < 0.0f ) ret = false; } return true; }

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  • My Dog, Cross-Channel Shopping, and Fusion SCM

    - by Kathryn Perry
    A guest post by Mark Carson, Director, Oracle Fusion Supply Chain Management I was walking my dog Max in an open space behind my house. As we tromped through the tall weeds I remembered it is tick season and that I should get Max some protection. While he sniffed merrily in the tick infested brush, I started shopping in the middle of an open field on my phone. I thought it would be convenient to pick up the tick medicine from a pet store on the way home. Searching the pet store website I saw that they had the medicine, but there was no information on whether the store had any in stock and there were no options for shipping it to the store for pickup. I could return it, but not pick it up which seamed kind of odd. I really didn't feel like making calls to the local stores to find out if they had it. Since the product is popular, I tried one of the large 'everything' stores. Browsing its website I could see that it could be shipped to me, shipped to the store for free, and that the store nearest to me had it in stock. Needless to say, this store became a better option. This experience is a small example of why retailers, distributors, and manufactures have placed a high priority on enabling 'cross-channel commerce.' Shoppers like you and me expect to be able to search, compare, buy and return products on-line and over the phone using a variety of devices including PDAs, tablets and in-store kiosks. The pet store lost my business because its web channel had limited information about its stores. I have spoken with many customers and prospects about cross-channel commerce. They all realize the business implications and urgency behind cross-channel commerce but recognize there are challenges to enable it. New and existing applications must be integrated together globally through a consistent cross-channel business process. Integration is required between applications that provide the initial shopping experience and delivery applications associated with warehouses, stores, and partners. The enablement must be accomplished in a flexible way to react to fast-changing product portfolios and new acquisitions, while at the same time minimizing costs through reuse of existing systems. Meanwhile, the business must continue to grow and decision makers need to balance new capability with peak seasons. The challenges above are not unique to retail. Any customer in any industry who has multiple points for capturing orders and multiple points for fulfilling orders will face these challenges. With this in mind, we had a unique opportunity in Fusion SCM to re-think how to build a set of modular and flexible applications in the order management space that would make these challenges easier to conquer. The results are Fusion Distributed Order Orchestration and Global Order Promising. These applications can help companies, such as the pet store, enable true cross-channel commerce. The apps provide highly adaptable and flexible business processes to automate order orchestration across multiple cross-channel systems. They also show a global view of supply across warehouses, stores, and partners for real-time availability and more accurate order promising. Additional capability includes a standards-based integration framework for seamless execution and the ability to reuse existing systems for faster and lower cost implementations. OK, that was a mouthful of features and benefits. As Max waited to cross the street (he can do basic math too), I wondered if he could relate. He does not care about leash laws, pick-up courtesy, where he can/can't walk, what time of day it is, or even ticks. He does not care about how all these things could make walking complicated. He just wants to walk. Similarly, customers just want to shop and companies just want to make it easier to sell and deliver. You can learn more about Distributed Order Orchestration and Global Order Promising in cross-channel here.

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  • Moving monarchs and dragons: migrating the JDK bugs to JIRA

    - by darcy
    Among insects, monarch butterflies and dragonflies have the longest migrations; migrating JDK bugs involves a long journey as well! As previously announced by Mark back in March, we've been working according to a revised plan to transition the JDK bug management from Sun's legacy system to initially an Oracle-internal JIRA instance which is afterward made visible and usable externally. I've been busily working on this project for the last few months and the team has made good progress on many aspects of the effort: JDK bugs will be imported into JIRA regardless of age; bugs will also be imported regardless of state, including closed bugs. Consequently, the JDK bug project will start pre-populated with over 100,000 existing bugs, some dating all the way back to 1994. This will allow a continuity of information and allow new issues to be linked to old ones. Using a custom import process, the Sun bug numbers will be preserved in JIRA. For example, the Sun bug with bug number 4040458 will become "JDK-4040458" in JIRA. In JIRA the project name, "JDK" in our case, is part of the bug's identifier. Bugs created after the JIRA migration will be numbered starting at 8000000; bugs imported from the legacy system have numbers ranging between 1000000 and 79999999. We're working with the bugs.sun.com team to try to maintain continuity of the ability to both read JDK bug information as well as to file new incidents. At least for now, the overall architecture of bugs.sun.com will be the same as it is today: it will be a gateway bridging to an Oracle-internal system, but the internal system will change to JIRA from the legacy database. Generally we are aiming to preserve the visibility of bugs currently viewable on bugs.sun.com; however, bugs in areas not related to the JDK will not be visible after the transition to JIRA. New incoming incidents will be sent to a separate JIRA project for initial triage before possibly being moved into the JDK project. JDK bug management leans heavily on being able to track the state of bugs in multiple releases, especially to coordinate delivering synchronized security releases (known as CPUs, critital patch updates, in Oracle parlance). For a security release, it is common for half a dozen or more release trains to be affected (for example, JDK 5, JDK 6 update, OpenJDK 6, JDK 7 update, JDK 8, virtual releases for HotSpot express, etc.). We've determined we need to track at least the tuple of (release, responsible engineer/assignee for the release, status in the release) for the release trains a fix is going into. To do this in JIRA, we are creating a separate port/backport issue type along with a custom link type to allow the multiple release information to be easily grouped and presented together. The Sun legacy system had a three-level classification scheme, product, category, and subcategory. Out of the box, JIRA only has a one-level classification, component. We've implemented a custom second-level classification, subcomponent. As part of the bug migration we've taken the opportunity to think about how bugs should be grouped under a two-level system and we'll the new system will be simpler and more regular. The main top-level components of the JDK product will include: core-libs client-libs deploy install security-libs other-libs tools hotspot For the libs areas, the primary name of the subcomportment will be the package of the API in question. In the core-libs component, there will be subcomponents like: java.lang java.lang.class_loading java.math java.util java.util:i18n In the tools component, subcomponents will primarily correspond to command names in $JDK/bin like, jar, javac, and javap. The first several bulk imports of the JDK bugs into JIRA have gone well and we're continuing to refine the import to have greater fidelity to the current data, including by reconstructing information not brought over in a structured fashion during the previous large JDK bug system migration back in 2004. We don't currently have a firm timeline of when the new system will be usable externally, but as it becomes available, I'll share further information in follow-up blog posts.

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  • what differs a computer scientist/software engineer to regular people who learn programming language and APIs?

    - by Amumu
    In University, we learn and reinvent the wheel a lot to truly learn the programming concepts. For example, we may learn assembly language to understand, what happens inside the box, and how the system operates, when we execute our code. This helps understanding higher level concepts deeper. For example, memory management like in C is just an abstraction of manually managed memory contents and addresses. The problem is, when we're going to work, usually productivity is required more. I could program my own containers, or string class, or date/time (using POSIX with C system call) to do the job, but then, it would take much longer time to use existing STL or Boost library, which abstract all of those thing and very easy to use. This leads to an issue, that a regular person doesn't need to get through all the low level/under the hood stuffs, who learns only one programming language and using language-related APIs. These people may eventually compete with the mainstream graduates from computer science or software engineer and call themselves programmers. At first, I don't think it's valid to call them programmers. I used to think, a real programmer needs to understand the computer deeply (but not at the electronic level). But then I changed my mind. After all, they get the job done and satisfy all the test criteria (logic, performance, security...), and in business environment, who cares if you're an expert and understand how computer works or not. You may get behind the "amateurs" if you spend to much time learning about how things work inside. It is totally valid for those people to call themselves programmers. This makes me confuse. So, after all, programming should be considered an universal skill? Does programming language and concepts matter or the problems we solve matter? For example, many C/C++ vs Java and other high level language, one of the main reason is because C/C++ features performance, as well as accessing low level facility. One of the main reason (in my opinion), is coding in C/C++ seems complex, so people feel good about it (not trolling anyone, just my observation, and my experience as well. Try to google "C hacker syndrome"). While Java on the other hand, made for simplifying programming tasks to help developers concentrate on solving their problems. Based on Java rationale, if the programing language keeps evolve, one day everyone can map their logic directly with natural language. Everyone can program. On that day, maybe real programmers are mathematicians, who could perform most complex logic (including business logic and academic logic) without worrying about installing/configuring compiler, IDEs? What's our job as a computer scientist/software engineer? To solve computer specific problems or to solve problems in general? For example, take a look at this exame: http://cm.baylor.edu/ICPCWiki/attach/Problem%20Resources/2010WorldFinalProblemSet.pdf . The example requires only basic knowledge about the programming language, but focus more on problem solving with the language. In sum, what differs a computer scientist/software engineer to regular people who learn programming language and APIs? A mathematician can be considered a programmer, if he is good enough to use programming language to implement his formula. Can we programmer do this? Probably not for most of us, since we specialize about computer, not math. An electronic engineer, who learns how to use C to program for his devices, can be considered a programmer. If the programming languages keep being simplified, may one day the software engineers, who implements business logic and create softwares, be obsolete? (Not for computer scientist though, since many of the CS topics are scientific, and science won't change, but technology will).

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  • Library order is important

    - by Darryl Gove
    I've written quite extensively about link ordering issues, but I've not discussed the interaction between archive libraries and shared libraries. So let's take a simple program that calls a maths library function: #include <math.h int main() { for (int i=0; i<10000000; i++) { sin(i); } } We compile and run it to get the following performance: bash-3.2$ cc -g -O fp.c -lm bash-3.2$ timex ./a.out real 6.06 user 6.04 sys 0.01 Now most people will have heard of the optimised maths library which is added by the flag -xlibmopt. This contains optimised versions of key mathematical functions, in this instance, using the library doubles performance: bash-3.2$ cc -g -O -xlibmopt fp.c -lm bash-3.2$ timex ./a.out real 2.70 user 2.69 sys 0.00 The optimised maths library is provided as an archive library (libmopt.a), and the driver adds it to the link line just before the maths library - this causes the linker to pick the definitions provided by the static library in preference to those provided by libm. We can see the processing by asking the compiler to print out the link line: bash-3.2$ cc -### -g -O -xlibmopt fp.c -lm /usr/ccs/bin/ld ... fp.o -lmopt -lm -o a.out... The flag to the linker is -lmopt, and this is placed before the -lm flag. So what happens when the -lm flag is in the wrong place on the command line: bash-3.2$ cc -g -O -xlibmopt -lm fp.c bash-3.2$ timex ./a.out real 6.02 user 6.01 sys 0.01 If the -lm flag is before the source file (or object file for that matter), we get the slower performance from the system maths library. Why's that? If we look at the link line we can see the following ordering: /usr/ccs/bin/ld ... -lmopt -lm fp.o -o a.out So the optimised maths library is still placed before the system maths library, but the object file is placed afterwards. This would be ok if the optimised maths library were a shared library, but it is not - instead it's an archive library, and archive library processing is different - as described in the linker and library guide: "The link-editor searches an archive only to resolve undefined or tentative external references that have previously been encountered." An archive library can only be used resolve symbols that are outstanding at that point in the link processing. When fp.o is placed before the libmopt.a archive library, then the linker has an unresolved symbol defined in fp.o, and it will search the archive library to resolve that symbol. If the archive library is placed before fp.o then there are no unresolved symbols at that point, and so the linker doesn't need to use the archive library. This is why libmopt needs to be placed after the object files on the link line. On the other hand if the linker has observed any shared libraries, then at any point these are checked for any unresolved symbols. The consequence of this is that once the linker "sees" libm it will resolve any symbols it can to that library, and it will not check the archive library to resolve them. This is why libmopt needs to be placed before libm on the link line. This leads to the following order for placing files on the link line: Object files Archive libraries Shared libraries If you use this order, then things will consistently get resolved to the archive libraries rather than to the shared libaries.

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  • Refactoring existing PHP Project. I need some advices

    - by b0x
    i have a small SAS ERP that was written some years ago using PHP. At that time, it didn't used any framework, but the code isn't a mess as i will explain more detailed in the following lines. Nowadays, the project grow and I’m now working with 3 more programmers. Often, they ask to me why we don’t migrate to a framework such Laravel. Although I'd love trying Laravel, I’m a small business and i don't have time/money to stop and spend a whole year building everything from scratch. I need to live and pay the bills. So, I've read a lot about this matter, and I decided that doing a refactoring is the best way to do it. Also, I'm not so sure that a framework will make things easy. Business goals are: Make the code easier to new hired programmers I must separate the "view", because: I want to release different versions of this product (using the same code), but under different brands and websites at the minimum cost (just changing view) Release different versions to fit mobile/tablet. Make different types of this product, seeling packages as if it were plugins. Develop custom packages for some costumers (like plugins/addon's that they can buy to put on the main application). Code goals: Introduce best pratices, standards for everyone Try to build my own MVC structure Improve validation of data/forms (today they are mixed in both ajax and classes) Create automated testing rotines, to quality assurance. My actual structure project: class\ extra\ hd\ logs\ public_html\ public_html\includes\ public_html\css|js|images\ class\ There are three types of classes. They are all “autoloaded” with something similar with PSR-0, but I don’t use namespaces. 1. class.Something.php Connects to Database using specific methods. I.e: Costumer-list(); It uses “class.Db.php”, that it’s an abstraction of mysqli on every method. 2. class.SomethingProc.php Do things that “join” things that come from “class.Something.php”. Like IF/ELSE, math operations. 3. class.SomethingHTML.php The classes with “HTML” suffix implements only static methods and HTML code only. A real life example: All the programmers need to use $cSomething ($c to class) and $arrSomething (to array). Costumer.php (view) <?php $cCosumter = new Costumer(); $arrCostumer = $cCostumer->list(); echo CostumerHTML::table($arrCostumer); ?> Extra\ Store 3rdparty projects/classes from others, such MPDF, PHPMailer, etc. Hd\ Store user’s fies outsite wwwroot dir. Logs\ Store phplogs and the system itself logs (We have a static Log::error() method, that we put in every method of every class) Public_html\ Stores the files that people use. Public_html\includes\ Store the main “config.php” file and all files that do “ajax things” ajax.Costumer.php, for example. Help is needed ;) So, as you can see we have some standards, and also for database things. But i want to write a manual of our rules. Something that i can give to any new programmer at my companie and he can go on. This is not totally a mess, but It could be better seeing the new practices. What could I do to separate this as MVC, to have multiple VIEW’s. Could you gimme some tips considering my goals? Keep im mind the different products/custom things for specific costumers without breaking the main application. URL for tutorials, books, etc. It would be nice. Thanks!

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  • Advice on refactoring PHP Project

    - by b0x
    I have a small SAS ERP that was written some years ago using PHP. At that time, it didn't use any framework, but the code isn't a mess. Nowadays, the project grows and I’m now working with 3 more programmers. Often, they ask to me why we don’t migrate to a framework such as Laravel. Although I'd love trying Laravel, I’m a small business and I don't have time nor money to stop and spend a whole year building everything from scratch. I need to live and pay the bills. So, I've read a lot about this matter, and I decided that doing a refactoring is the best way to do it. Also, I'm not so sure that a framework will make things easy. Business goals are: Make the code easier to new hired programmers Separate the "view", in order to: release different versions of this product (using the same code), but under different brands and websites at the minimum cost (just changing view) release different versions to fit mobile/tablet. Make different types of this product, selling packages as if they were plugins. Develop custom packages for some costumers (like plugins/addon's that they can buy to put on the main application). Code goals: Introduce best pratices, standards for everyone Try to build my own MVC structure Improve validation of data/forms (today they are mixed in both ajax and classes) Create automated testing routines for quality assurance. My current structure project: class\ extra\ hd\ logs\ public_html\ public_html\includes\ public_html\css|js|images\ class\ There are three types of classes. They are all “autoloaded” with something similar with PSR-0, but I don’t use namespaces. 1. class.Something.php Connects to Database using specific methods. I.e: Costumer-list(); It uses “class.Db.php”, that it’s an abstraction of mysql on every method. 2. class.SomethingProc.php Do things that “join” things that come from “class.Something.php”. Like IF/ELSE, math operations. 3. class.SomethingHTML.php The classes with “HTML” suffix implements only static methods and HTML code only. A real life example: All the programmers need to use $cSomething ($c to class) and $arrSomething (to array). Costumer.php (view) <?php $cCosumter = new Costumer(); $arrCostumer = $cCostumer->list(); echo CostumerHTML::table($arrCostumer); ?> Extra\ Store 3rdparty projects/classes from others, such MPDF, PHPMailer, etc. Hd\ Store user’s files outsite wwwroot dir. Logs\ Store phplogs and the system itself logs (We have a static Log::error() method, that we put in every method of every class) Public_html\ Stores the files that people use. Public_html\includes\ Store the main “config.php” file and all files that do “ajax things” ajax.Costumer.php, for example. Help is needed ;) So, as you can see we have some standards, and also for database things. But I want to write a manual of our rules. Something that I can give to any new programmer at my company and he can go on. This is not totally a mess, but it could be better seeing the new practices. What could I do to separate this as MVC, to have multiple views. Could you give me some tips considering my goals? Keep im mind the different products/custom things for specific costumers without breaking the main application. URL for tutorials, books, etc, would be nice.

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  • Libgdx 2D Game, Random generated World of random size, how to get mouse coordinates?

    - by Solom
    I'm a noob and English is not my mothertongue, so please bear with me! I'm generating a map for a Sidescroller out of a 2D-array. That is, the array holds different values and I create blocks based on that value. Now, my problem is to match mouse coordinates on screen with the actual block the mouse is pointing at. public class GameScreen implements Screen { private static final int WIDTH = 100; private static final int HEIGHT = 70; private OrthographicCamera camera; private Rectangle glViewport; private Spritebatch spriteBatch; private Map map; private Block block; ... @Override public void show() { camera = new OrthographicCamera(WIDTH, HEIGHT); camera.position.set(WIDTH/2, HEIGHT/2, 0); glViewport = new Rectangle(0, 0, WIDTH, HEIGHT); map = new Map(16384, 256); map.printTileMap(); // Debugging only spriteBatch = new SpriteBatch(); } @Override public void render(float delta) { // Clear previous frame Gdx.gl.glClearColor(1, 1, 1, 1 ); Gdx.gl.glClear(GL20.GL_COLOR_BUFFER_BIT); GL30 gl = Gdx.graphics.getGL30(); // gl.glViewport((int) glViewport.x, (int) glViewport.y, (int) glViewport.width, (int) glViewport.height); spriteBatch.setProjectionMatrix(camera.combined); camera.update(); spriteBatch.begin(); // Draw Map this.drawMap(); // spriteBatch.flush(); spriteBatch.end(); } private void drawMap() { for(int a = 0; a < map.getHeight(); a++) { // Bounds check (y) if(camera.position.y + camera.viewportHeight < a)// || camera.position.y - camera.viewportHeight > a) break; for(int b = 0; b < map.getWidth(); b++) { // Bounds check (x) if(camera.position.x + camera.viewportWidth < b)// || camera.position.x > b) break; // Dynamic rendering via BlockManager int id = map.getTileMap()[a][b]; Block block = BlockManager.map.get(id); if(block != null) // Check if Air { block.setPosition(b, a); spriteBatch.draw(block.getTexture(), b, a, 1 ,1); } } } } As you can see, I don't use the viewport anywhere. Not sure if I need it somewhere down the road. So, the map is 16384 blocks wide. One block is 16 pixels in size. One of my naive approaches was this: if(Gdx.input.isButtonPressed(Input.Buttons.LEFT)) { Vector3 mousePos = new Vector3(); mousePos.set(Gdx.input.getX(), Gdx.input.getY(), 0); camera.unproject(mousePos); System.out.println(Math.round(mousePos.x)); // *16); // Debugging // TODO: round // map.getTileMap()[mousePos.x][mousePos.y] = 2; // Draw at mouse position } I confused myself somewhere down the road I fear. What I want to do is, update the "block" (or rather the information in the Map/2D-Array) so that in the next render() there is another block. Basically drawing on the spriteBatch g So if anyone could point me in the right direction this would be highly appreciated. Thanks!

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  • Improving the efficiency of frustum culling

    - by DeadMG
    I've got some code which performs frustum culling. However, this defines the "frustum" way too broadly- when I have ~10 objects on screen, the code returns 42 objects to be rendered. I've tried taking "slices" through the frustum to attempt to increase the accuracy of the technique, but it doesn't seem to have made much impact. I also significantly reduced the far plane, so that the objects are barely at the edge. Here's my code (where size is the size in screen space- the resolution of the client area of the window I'm rendering into). Any suggestions? auto&& size = GetDimensions(); D3DVIEWPORT9 vp = { 0, 0, size.x, size.y, 0, 1 }; D3DCALL(device->SetViewport(&vp)); static const int slices = 10; std::vector<Object*> result; for(int i = 0; i < slices; i++) { D3DXVECTOR3 WorldSpaceFrustrumPoints[8] = { D3DXVECTOR3(0, size.y, static_cast<float>(i) / slices), D3DXVECTOR3(size.x, 0, static_cast<float>(i) / slices), D3DXVECTOR3(size.x, size.y, static_cast<float>(i) / slices), D3DXVECTOR3(0, 0, static_cast<float>(i) / slices), D3DXVECTOR3(0, 0, static_cast<float>(i + 1) / slices), D3DXVECTOR3(size.x, 0, static_cast<float>(i + 1) / slices), D3DXVECTOR3(size.x, size.y, static_cast<float>(i + 1) / slices), D3DXVECTOR3(0, size.y, static_cast<float>(i + 1) / slices) }; D3DXMATRIXA16 Identity; D3DXMatrixIdentity(&Identity); D3DXVec3UnprojectArray( WorldSpaceFrustrumPoints, sizeof(D3DXVECTOR3), WorldSpaceFrustrumPoints, sizeof(D3DXVECTOR3), &vp, &Projection, &View, &Identity, 8 ); Math::AABB Frustrum; auto world_begin = std::begin(WorldSpaceFrustrumPoints); auto world_end = std::end(WorldSpaceFrustrumPoints); auto world_initial = WorldSpaceFrustrumPoints[0]; Frustrum.BottomLeftClosest.x = std::accumulate(world_begin, world_end, world_initial, [](D3DXVECTOR3 lhs, D3DXVECTOR3 rhs) { return lhs.x < rhs.x ? lhs : rhs; }).x; Frustrum.BottomLeftClosest.y = std::accumulate(world_begin, world_end, world_initial, [](D3DXVECTOR3 lhs, D3DXVECTOR3 rhs) { return lhs.y < rhs.y ? lhs : rhs; }).y; Frustrum.BottomLeftClosest.z = std::accumulate(world_begin, world_end, world_initial, [](D3DXVECTOR3 lhs, D3DXVECTOR3 rhs) { return lhs.z < rhs.z ? lhs : rhs; }).z; Frustrum.TopRightFurthest.x = std::accumulate(world_begin, world_end, world_initial, [](D3DXVECTOR3 lhs, D3DXVECTOR3 rhs) { return lhs.x > rhs.x ? lhs : rhs; }).x; Frustrum.TopRightFurthest.y = std::accumulate(world_begin, world_end, world_initial, [](D3DXVECTOR3 lhs, D3DXVECTOR3 rhs) { return lhs.y > rhs.y ? lhs : rhs; }).y; Frustrum.TopRightFurthest.z = std::accumulate(world_begin, world_end, world_initial, [](D3DXVECTOR3 lhs, D3DXVECTOR3 rhs) { return lhs.z > rhs.z ? lhs : rhs; }).z; auto slices_result = ObjectTree.collision(Frustrum); result.insert(result.end(), slices_result.begin(), slices_result.end()); } return result;

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  • Using HTML5 Today part 3&ndash; Using Polyfills

    - by Steve Albers
    Shims helps when adding semantic tags to older IE browsers, but there is a huge range of other new HTML5 features that having varying support on browsers.  Polyfills are JavaScript code and/or browser plug-ins that can provide older or less featured browsers with API support.  The best polyfills will detect the whether the current browser has native support, and only adds the functionality if necessary.  The Douglas Crockford JSON2.js library is an example of this approach: if the browser already supports the JSON object, nothing changes.  If JSON is not available, the library adds a JSON property in the global object. This approach provides some big benefits: It lets you add great new HTML5 features to your web sites sooner. It lets the developer focus on writing to the up-and-coming standard rather than proprietary APIs. Where most one-off legacy code fixes tends to break down over time, well done polyfills will stop executing over time (as customer browsers natively support the feature) meaning polyfill code may not need to be tested against new browsers since they will execute the native methods instead. Your should also remember that Polyfills represent an entirely separate code path (and sometimes plug-in) that requires testing for support.  Also Polyfills tend to run on older browsers, which often have slower JavaScript performance.  As a result you might find that performance on older browsers is not comparable. When looking for Polyfills you can start by checking the Modernizr GitHub wiki or the HTML5 Please site. For an example of a polyfill consider a page that writes a few geometric shapes on a <canvas> <script src="jquery-1.7.1.min.js"><script> <script> $(document).ready(function () { drawCanvas(); }); function drawCanvas() { var context = $("canvas")[0].getContext('2d'); //background context.fillStyle = "#8B0000"; context.fillRect(5, 5, 300, 100); // emptybox context.strokeStyle = "#B0C4DE"; context.lineWidth = 4; context.strokeRect(20, 15, 80, 80); // circle context.arc(160, 55, 40, 0, Math.PI * 2, false); context.fillStyle = "#4B0082"; context.fill(); </script>   The result is a simple static canvas with a box & a circle:   …to enable this functionality on a pre-canvas browser we can find a polyfill.  A check on html5please.com references  FlashCanvas.  Pull down the zip and extract the files (flashcanvas.js, flash10canvas.swf, etc) to a directory on your site.  Then based on the documentation you need to add a single line to your original HTML file: <!--[if lt IE 9]><script src="flashcanvas.js"></script><![endif]—> …and you have canvas functionality!  The IE conditional comments ensure that the library is only loaded in browsers where it is useful, improving page load & processing time. Like all Polyfills, you should test to verify the functionality matches your expectations across browsers you need to support.  For instance the Flash Canvas home page advertises 70% support of HTML5 Canvas spec tests.

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  • Resolving collisions between dynamic game objects

    - by TheBroodian
    I've been building a 2D platformer for some time now, I'm getting to the point where I am adding dynamic objects to the stage for testing. This has prompted me to consider how I would like my character and other objects to behave when they collide. A typical staple in many 2D platformer type games is that the player takes damage upon touching an enemy, and then essentially becomes able to pass through enemies during a period of invulnerability, and at the same time, enemies are able to pass through eachother freely. I personally don't want to take this approach, it feels strange to me that the player should receive arbitrary damage for harmless contact to an enemy, despite whether the enemy is attacking or not, and I would like my enemies' interactions between each other (and my player) to be a little more organic, so to speak. In my head I sort of have this idea where a game object (player, or non player) would be able to push other game objects around by manner of 'pushing' each other out of one anothers' bounding boxes if there is an intersection, and maybe correlate the repelling force to how much their bounding boxes are intersecting. The problem I'm experiencing is I have no idea what the math might look like for something like this? I'll show what work I've done so far, it sort of works, but it's jittery, and generally not quite what I would pass in a functional game: //Clears the anti-duplicate buffer collisionRecord.Clear(); //pick a thing foreach (GameObject entity in entities) { //pick another thing foreach (GameObject subject in entities) { //check to make sure both things aren't the same thing if (!ReferenceEquals(entity, subject)) { //check to see if thing2 is in semi-near proximity to thing1 if (entity.WideProximityArea.Intersects(subject.CollisionRectangle) || entity.WideProximityArea.Contains(subject.CollisionRectangle)) { //check to see if thing2 and thing1 are colliding. if (entity.CollisionRectangle.Intersects(subject.CollisionRectangle) || entity.CollisionRectangle.Contains(subject.CollisionRectangle) || subject.CollisionRectangle.Contains(entity.CollisionRectangle)) { //check if we've already resolved their collision or not. if (!collisionRecord.ContainsKey(entity.GetHashCode())) { //more duplicate resolution checking. if (!collisionRecord.ContainsKey(subject.GetHashCode())) { //if thing1 is traveling right... if (entity.Velocity.X > 0) { //if it isn't too far to the right... if (subject.CollisionRectangle.Contains(new Microsoft.Xna.Framework.Rectangle(entity.CollisionRectangle.Right, entity.CollisionRectangle.Y, 1, entity.CollisionRectangle.Height)) || subject.CollisionRectangle.Intersects(new Microsoft.Xna.Framework.Rectangle(entity.CollisionRectangle.Right, entity.CollisionRectangle.Y, 1, entity.CollisionRectangle.Height))) { //Find how deep thing1 is intersecting thing2's collision box; float offset = entity.CollisionRectangle.Right - subject.CollisionRectangle.Left; //Move both things in opposite directions half the length of the intersection, pushing thing1 to the left, and thing2 to the right. entity.Velocities.Add(new Vector2(-(((offset * 4) * (float)gameTime.ElapsedGameTime.TotalMilliseconds)), 0)); subject.Velocities.Add(new Vector2((((offset * 4) * (float)gameTime.ElapsedGameTime.TotalMilliseconds)), 0)); } } //if thing1 is traveling left... if (entity.Velocity.X < 0) { //if thing1 isn't too far left... if (entity.CollisionRectangle.Contains(new Microsoft.Xna.Framework.Rectangle(subject.CollisionRectangle.Right, subject.CollisionRectangle.Y, 1, subject.CollisionRectangle.Height)) || entity.CollisionRectangle.Intersects(new Microsoft.Xna.Framework.Rectangle(subject.CollisionRectangle.Right, subject.CollisionRectangle.Y, 1, subject.CollisionRectangle.Height))) { //Find how deep thing1 is intersecting thing2's collision box; float offset = subject.CollisionRectangle.Right - entity.CollisionRectangle.Left; //Move both things in opposite directions half the length of the intersection, pushing thing1 to the right, and thing2 to the left. entity.Velocities.Add(new Vector2((((offset * 4) * (float)gameTime.ElapsedGameTime.TotalMilliseconds)), 0)); subject.Velocities.Add(new Vector2(-(((offset * 4) * (float)gameTime.ElapsedGameTime.TotalMilliseconds)), 0)); } } //Make record that thing1 and thing2 have interacted and the collision has been solved, so that if thing2 is picked next in the foreach loop, it isn't checked against thing1 a second time before the next update. collisionRecord.Add(entity.GetHashCode(), subject.GetHashCode()); } } } } } } } } One of the biggest issues with my code aside from the jitteriness is that if one character were to land on top of another character, it very suddenly and abruptly resolves the collision, whereas I would like a more subtle and gradual resolution. Any thoughts or ideas are incredibly welcome and helpful.

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  • What Counts For a DBA – Depth

    - by Louis Davidson
    SQL Server offers very simple interfaces to many of its features. Most people could open up SSMS, connect to a server, write a simple query and see the results. Even several of the core DBA tasks are deceptively straightforward. It doesn’t take a rocket scientist to perform a basic database backup or run a trace (even using the newfangled Extended Events!). However, appearances can be deceptive, and often times it is really important that a DBA understands not just the basics of how to perform a task, but why we do a task, and how that task works. As an analogy, consider a child walking into a darkened room. Most would know that they need to turn on the light, and how to do it, so they flick the switch. But what happens if light fails to shine forth. Most would immediately tell you that you need to consider changing the light bulb. So you hop in the car and take them to the local home store and instruct them to buy a replacement. Confronted with a 40 foot display of light bulbs, how will they decide which of the hundreds of types of bulbs, of different types, fittings, shapes, colors, power and efficiency ratings, is the right choice? Obviously the main lesson the child is going to learn this day is how to use their cell phone as a flashlight so they don’t have to ask for help the next time. Likewise, when the metaphorical toddlers who use your database server have issues, they will instinctively know something is wrong, and may even have some idea what caused it, but will have no depth of knowledge to figure out the right solution. That is where the DBA comes in and attempts to save the day. However, when one looks beneath the shiny UI, SQL Server has its own “40 foot display of light bulbs”, in the form of the tremendous number of tools and the often-bewildering amount of information they can present to the DBA, to help us find issues. Unfortunately, resorting to guesswork, to trying different “bulbs” over and over, hoping to stumble on the answer. This is where the right depth of knowledge goes a long way. If we need to write a SELECT statement, then knowing the syntax and where to find the data is not enough. Knowledge of indexes and query plans is essential. Without it, we might hit on a query that “works”, but we are basically still a user, not a programmer, because we have no real control over our platform. Is that level of knowledge deep enough? Probably not, since knowledge of the underlying metadata and structures would be very useful in helping us make sense of any query plan. Understanding the structure of an index makes the “key lookup” operator not sound like what you do when someone tapes your car key to the ceiling. So is even this level of understanding deep enough? Do we need to understand the memory architecture used to process the query? It might be a comforting level of knowledge, and will doubtless come in handy at some point, but is not strictly necessary in most cases. Beyond that lies (more or less) full knowledge of SQL language and the intricacies of every step the SQL Server engine takes to process our query. My personal theory is that, as a professional, our knowledge of a given task should extend, at a minimum, one level deeper than is strictly necessary to perform the task. Anything deeper can be left to the ridiculously smart, or obsessive, or both. As an example. tasked with storing an integer value between 0 and 99999999, it’s essential that I know that choosing an Integer over Decimal(8,0) will likely offer performance benefits. It is then useful that I also understand the value of adding a CHECK constraint, to make sure the values are valid to the desired range; and comforting that I know a little about the underlying processors, registers and computer math. Anything further, I leave to the likes of Joe Chang, whose recent blog post on the topic offers depth by the bucketful!  

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  • Problem with sprite direction and rotation

    - by user2236165
    I have a sprite called Tool that moves with a speed represented as a float and in a direction represented as a Vector2. When I click the mouse on the screen the sprite change its direction and starts to move towards the mouseclick. In addition to that I rotate the sprite so that it is facing in the direction it is heading. However, when I add a camera that is suppose to follow the sprite so that the sprite is always centered on the screen, the sprite won't move in the given direction and the rotation isn't accurate anymore. This only happens when I add the Camera.View in the spriteBatch.Begin(). I was hoping anyone could maybe shed a light on what I am missing in my code, that would be highly appreciated. Here is the camera class i use: public class Camera { private const float zoomUpperLimit = 1.5f; private const float zoomLowerLimit = 0.1f; private float _zoom; private Vector2 _pos; private int ViewportWidth, ViewportHeight; #region Properties public float Zoom { get { return _zoom; } set { _zoom = value; if (_zoom < zoomLowerLimit) _zoom = zoomLowerLimit; if (_zoom > zoomUpperLimit) _zoom = zoomUpperLimit; } } public Rectangle Viewport { get { int width = (int)((ViewportWidth / _zoom)); int height = (int)((ViewportHeight / _zoom)); return new Rectangle((int)(_pos.X - width / 2), (int)(_pos.Y - height / 2), width, height); } } public void Move(Vector2 amount) { _pos += amount; } public Vector2 Position { get { return _pos; } set { _pos = value; } } public Matrix View { get { return Matrix.CreateTranslation(new Vector3(-_pos.X, -_pos.Y, 0)) * Matrix.CreateScale(new Vector3(Zoom, Zoom, 1)) * Matrix.CreateTranslation(new Vector3(ViewportWidth * 0.5f, ViewportHeight * 0.5f, 0)); } } #endregion public Camera(Viewport viewport, float initialZoom) { _zoom = initialZoom; _pos = Vector2.Zero; ViewportWidth = viewport.Width; ViewportHeight = viewport.Height; } } And here is my Update and Draw-method: protected override void Update (GameTime gameTime) { float elapsed = (float)gameTime.ElapsedGameTime.TotalSeconds; TouchCollection touchCollection = TouchPanel.GetState (); foreach (TouchLocation tl in touchCollection) { if (tl.State == TouchLocationState.Pressed || tl.State == TouchLocationState.Moved) { //direction the tool shall move towards direction = touchCollection [0].Position - toolPos; if (direction != Vector2.Zero) { direction.Normalize (); } //change the direction the tool is moving and find the rotationangle the texture must rotate to point in given direction toolPos += (direction * speed * elapsed); RotationAngle = (float)Math.Atan2 (direction.Y, direction.X); } } if (direction != Vector2.Zero) { direction.Normalize (); } //move tool in given direction toolPos += (direction * speed * elapsed); //change cameracentre to the tools position Camera.Position = toolPos; base.Update (gameTime); } protected override void Draw (GameTime gameTime) { graphics.GraphicsDevice.Clear (Color.Blue); spriteBatch.Begin (SpriteSortMode.BackToFront, BlendState.AlphaBlend, null, null, null, null, Camera.View); spriteBatch.Draw (tool, new Vector2 (toolPos.X, toolPos.Y), null, Color.White, RotationAngle, originOfToolTexture, 1, SpriteEffects.None, 1); spriteBatch.End (); base.Draw (gameTime); }

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  • Software and/(x)or Hardware Projects for Pre-School Kids

    - by haylem
    I offered to participate at my kid's pre-school for various activities (yes, I'm crazy like that), and one of them is to help them discover extra-curricular (big word for a pre-school, but by lack of a better one... :)) hobbies, which may or may not relate to a professional activity. At first I thought that it wouldn't be really easy to have pre-schoolers relate to programming or the internal workings of a computer system in general (and I'm more used to teaching middle-school to university-level students), but then I thought there must be a way. So I'm trying to figure out ways to introduce very young kids (3yo) to computer systems in a fun and preferably educational way. Of course, I don't expect them to start smashing the stack for fun and profit right away (or at least not voluntarily, though I could use the occasion for some toddler tests...), but I'm confident there must be ways to get them interested in both: using the systems, becoming curious about understanding what they do, interacting with the systems to modify them. I guess this setting is not really relevant after all, it's pretty much the same as if you were aiming to achieve the same for your own kids at home. Ideas Considering we're talking 3yo pre-schoolers here, and that at this age some kids are already quite confident using a mouse (some even a keyboard, if not for typing, at least to press some buttons they've come to associate with actions) while others have not yet had any interaction with computers of any kind, it needs to be: rather basic, demonstrated and played with in less then 5 or 10 minutes, doable in in groups or alone, scalable and extendable in complexity to accommodate their varying abilities. The obvious options are: basic smallish games to play with, interactive systems like LOGO, Kojo, Squeak and clones (possibly even simpler than that), or thngs like Lego Systems. I guess it can be a thing to reflect on both at the software and the hardware levels: it could be done with a desktop or laptop machine, a tablet, a smartphone (or a crap-phone, for that matter, as long as you can modify it), or even get down to building something from scratch (Raspberry Pi and Arduino being popular options at the moment). I can probably be in the form of games, funny visualizations (which are pretty much games) w/ Prototype, virtual worlds to explore. I also thought on the moment (and I hope this won't offend anyone) that some approaches to teaching pets could work (reward systems, haptic feedback and such things could quickly point a kid in the right direction to understanding how things work, in a similar fashion - I'm not suggesting to shock the kids!). Hmm, Is There an Actual Question in There? What type of systems do you think might be a good fit, both in terms of hardware and software? Do you have seen such systems, or have anything in mind to work on? Are you aware of some research in this domain, with tangible results? Any input is welcome. It's not that I don't see options: there are tons, but I have a harder time pinpointing a more concrete and definite type of project/activity, so I figure some have valuable ideas or existing ones. Note: I am not advocating that every kid should learn to program, be interested in computer systems, or that all of them in a class would even care enough to follow such an introduction with more than a blank stare. I don't buy into the "everybody would benefit from learning to program" thing. Wouldn't hurt, but not necessary in any way. But if I can walk out of there with a few of them having smiled using the thing (or heck, cried because others took them away from them), that'd be good enough. Related Questions I've seen and that seem to complement what I'm looking for, but not exactly for the same age groups or with the same goals: Teaching Programming to Kids Recommendations for teaching kids math concepts & skills for programming?

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  • Slide 2d Vector to destination over a period of time

    - by SchautDollar
    I am making a library of GUI controls for games I make with XNA. I am currently developing the library as I make a game so I can test the features and find errors/bugs and hopefully smash them right away. My current issue is on a slide feature I want to implement for my base class that all controls inherit. My goal is to get the control to slide to a specified point over a specified amount of time. Here is the #region containing the code #region Slide private bool sliding; private Vector2 endPoint; private float slideTimeLeft; private float speed; private bool wasEnabled; private Vector2 slideDirection; private float slideDistance; public void Slide(Vector2 startPoint, Vector2 endPoint, float slideTime) { this.location = startPoint; Slide(endPoint,slideTime); } public void Slide(Vector2 endPoint, float slideTime) { this.wasEnabled = this.enabled; this.enabled = false; this.sliding = true; Vector2 tempLength = endPoint - this.location; this.slideDistance = tempLength.Length(); //Was this.slideDistance = (float)Math.Sqrt(tempLength.LengthSquared()); this.speed = slideTime / this.slideDistance; this.endPoint = endPoint; this.slideTimeLeft = slideTime; } private void UpdateSlide(GameTime gameTime) { if (this.sliding) { this.slideTimeLeft -= gameTime.ElapsedGameTime.Milliseconds; if (this.slideTimeLeft >= 0 ) { if ((this.endPoint-this.location).Length() != 0){//Was if (this.endPoint.LengthSquared() > 0 || this.location.LengthSquared() > 0) { this.slideDirection = Vector2.Normalize(this.endPoint - this.location); } this.location += this.slideDirection * speed * gameTime.ElapsedGameTime.Milliseconds;//This is where I believe the issue is, but I'm not sure. It seems right to me... (Even though it doesn't work) } else { this.enabled = this.wasEnabled; this.location = this.endPoint;//After time, the controls position will get set to be the endpoint. this.sliding = false; } } } #endregion this.location is the location of the control elsewhere defined in the class. I have looked at this blog as a huge reference and have googled around quite and have looked on many forums but can't find anything that shows how to implement it. Please and Thanks for your time! EDIT: I have switched this line "this.location += this.slideDirection * speed * gameTime.ElapsedGameTime.Milliseconds;" several times to see what it does. My issue is getting the control to smoothly move to the end location. It moves after the time has expired, but It doesn't move other then that except flash in my face. EDIT2: I have used the first slide method with 3 parameters and it works except it doesn't do it in a period of time and once it gets to its destination, it starts moving randomly towards the previous location and the end location.

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  • Why is 0 false?

    - by Morwenn
    This question may sound dumb, but why does 0 evaluates to false and any other [integer] value to true is most of programming languages? String comparison Since the question seems a little bit too simple, I will explain myself a little bit more: first of all, it may seem evident to any programmer, but why wouldn't there be a programming language - there may actually be, but not any I used - where 0 evaluates to true and all the other [integer] values to false? That one remark may seem random, but I have a few examples where it may have been a good idea. First of all, let's take the example of strings three-way comparison, I will take C's strcmp as example: any programmer trying C as his first language may be tempted to write the following code: if (strcmp(str1, str2)) { // Do something... } Since strcmp returns 0 which evaluates to false when the strings are equal, what the beginning programmer tried to do fails miserably and he generally does not understand why at first. Had 0 evaluated to true instead, this function could have been used in its most simple expression - the one above - when comparing for equality, and the proper checks for -1 and 1 would have been done only when needed. We would have considered the return type as bool (in our minds I mean) most of the time. Moreover, let's introduce a new type, sign, that just takes values -1, 0 and 1. That can be pretty handy. Imagine there is a spaceship operator in C++ and we want it for std::string (well, there already is the compare function, but spaceship operator is more fun). The declaration would currently be the following one: sign operator<=>(const std::string& lhs, const std::string& rhs); Had 0 been evaluated to true, the spaceship operator wouldn't even exist, and we could have declared operator== that way: sign operator==(const std::string& lhs, const std::string& rhs); This operator== would have handled three-way comparison at once, and could still be used to perform the following check while still being able to check which string is lexicographically superior to the other when needed: if (str1 == str2) { // Do something... } Old errors handling We now have exceptions, so this part only applies to the old languages where no such thing exist (C for example). If we look at C's standard library (and POSIX one too), we can see for sure that maaaaany functions return 0 when successful and any integer otherwise. I have sadly seen some people do this kind of things: #define TRUE 0 // ... if (some_function() == TRUE) { // Here, TRUE would mean success... // Do something } If we think about how we think in programming, we often have the following reasoning pattern: Do something Did it work? Yes -> That's ok, one case to handle No -> Why? Many cases to handle If we think about it again, it would have made sense to put the only neutral value, 0, to yes (and that's how C's functions work), while all the other values can be there to solve the many cases of the no. However, in all the programming languages I know (except maybe some experimental esotheric languages), that yes evaluates to false in an if condition, while all the no cases evaluate to true. There are many situations when "it works" represents one case while "it does not work" represents many probable causes. If we think about it that way, having 0 evaluate to true and the rest to false would have made much more sense. Conclusion My conclusion is essentially my original question: why did we design languages where 0 is false and the other values are true, taking in account my few examples above and maybe some more I did not think of? Follow-up: It's nice to see there are many answers with many ideas and as many possible reasons for it to be like that. I love how passionate you seem to be about it. I originaly asked this question out of boredom, but since you seem so passionate, I decided to go a little further and ask about the rationale behind the Boolean choice for 0 and 1 on Math.SE :)

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  • getting a job in game industry as a developer, just knowing a game engine

    - by numerical25
    I recently enrolled at a community college for game developement. But I am skeptical about the circulum. I have no experience in the gaming industry so I wouldnt be able to tell rather its a good investment or not. So I am asking you. I dont want to get too much into detail of all the classes I am taking so I will try to be brief. By the time I graduate, I should have a understanding of how a game engine works. I will be working with the unreal engine to develop a Multiplayer game from scratch. So in the process of my final project, I will learn how to work within the unreal engine, Learn python and learn how to use it's API to connect to a remote server and build game mechanics. Overall I will also recieve a associates degree in game development. I learn c++ but not c. The director said he was trying to implement c in the program as well. What I notice is I will not learn how to build a 3d game engine from scratch. They do not teach any AI. I will not learn how to work with the graphics card using a graphic's api such as DirectX or OpenGL. I know building a game engine from scratch is a little complex, but at the same time the track is requireing me to take some advances math courses such a calculus and geotomtry 1 and 2. I also got to take a physic class. I just think thats a little much for just learning how to use the unreal engine but not actually build one or try to learn the anatomy of a game engine. Is this good enough to possibly land my a job in the insdustry. If I left anything out or was not detail, please feel free to ask more questions. Thanks Guys!!

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  • Windows Azure : Storage Client Exception Unhandled

    - by veda
    I am writing a code for upload large files into the blobs using blocks... When I tested it, it gave me an StorageClientException It stated: One of the request inputs is out of range. I got this exception in this line of the code: blob.PutBlock(block, ms, null); Here is my code: protected void ButUploadBlocks_click(object sender, EventArgs e) { // store upladed file as a blob storage if (uplFileUpload.HasFile) { name = uplFileUpload.FileName; byte[] byteArray = uplFileUpload.FileBytes; Int64 contentLength = byteArray.Length; int numBytesPerBlock = 250 *1024; // 250KB per block int blocksCount = (int)Math.Ceiling((double)contentLength / numBytesPerBlock); // number of blocks MemoryStream ms ; List<string>BlockIds = new List<string>(); string block; int offset = 0; // get refernce to the cloud blob container CloudBlobContainer blobContainer = cloudBlobClient.GetContainerReference("documents"); // set the name for the uploading files string UploadDocName = name; // get the blob reference and set the metadata properties CloudBlockBlob blob = blobContainer.GetBlockBlobReference(UploadDocName); blob.Properties.ContentType = uplFileUpload.PostedFile.ContentType; for (int i = 0; i < blocksCount; i++, offset = offset + numBytesPerBlock) { block = Convert.ToBase64String(BitConverter.GetBytes(i)); ms = new MemoryStream(); ms.Write(byteArray, offset, numBytesPerBlock); blob.PutBlock(block, ms, null); BlockIds.Add(block); } blob.PutBlockList(BlockIds); blob.Metadata["FILETYPE"] = "text"; } } Can anyone tell me how to solve it...

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  • Silverlight 4 WriteableBitmap ScaleTransform Exception but was working in v3

    - by Imran
    I am getting the following exception for code that used to work in silverlight 3 but has stopped working since upgrading to silverlight 4: System.AccessViolationException was unhandled Message=Attempted to read or write protected memory. This is often an indication that other memory is corrupt. namespace SilverlightApplication1 { public partial class MainPage : UserControl { public MainPage() { InitializeComponent(); } private void button1_Click(object sender, RoutedEventArgs e) { var OpenFileDialog = new OpenFileDialog(); OpenFileDialog.Filter = "*.jpg|*.jpg"; if (OpenFileDialog.ShowDialog() == true) { var file = OpenFileDialog.Files.ToArray()[0]; ScaleStreamAsBitmap(file.OpenRead(), 200); } } public static WriteableBitmap ScaleStreamAsBitmap(Stream file, int maxEdgeLength) { file.Position = 0; var src = new BitmapImage(); var uiElement = new System.Windows.Controls.Image(); WriteableBitmap b = null; var t = new ScaleTransform(); src.SetSource(file); uiElement.Source = src; //force render uiElement.Effect = new DropShadowEffect() { ShadowDepth = 0, BlurRadius = 0 }; ; //calc scale double scaleX = 1; double scaleY = 1; if (src.PixelWidth > maxEdgeLength) scaleX = ((double)maxEdgeLength) / src.PixelWidth; if (src.PixelHeight > maxEdgeLength) scaleY = ((double)maxEdgeLength) / src.PixelHeight; double scale = Math.Min(scaleX, scaleY); t.ScaleX = scale; t.ScaleY = scale; b = new WriteableBitmap(uiElement, t); return b; } } } Thanks

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  • How to implement progress bar and backgroundworker for database calls C#?

    - by go-goo-go
    How to implement progress bar and backgroundworker for database calls C#? I do have some methods that deal with large amounts of data. They do last a lot, so in my windows application, i wanna do something to tell users that the data are being processed. So i thought of using progress bar or status strip label, but since there is a single ui thread, the thread where the database-dealing methods are executed, ui controls are not updated, so progress bar or status strip label are useless to me. I've already seen some examples, but they deal with for-loops, ex: for(int i = 0; i < count; i++){ System.Threading.Thread.Sleep(70); // ... do analysis ... bgWorker.ReportProgress((100 * i) / count);} private void bgWorker_ProgressChanged(object sender, ProgressChangedEventArgs e){ progressBar.Value = Math.Min(e.ProgressPercentage, 100);} Can anybody give an example where I can use a method call, not a for-loop, and let the progress bar run while this method is executing??? thnx in advance, any help and hint is highly appreciated.

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  • MP3 Decoding on Android

    - by Rob Szumlakowski
    Hi. We're implementing a program for Android phones that plays audio streamed from the internet. Here's approximately what we do: Download a custom encrypted format. Decrypt to get chunks of regular MP3 data. Decode MP3 data to raw PCM data in a memory buffer. Pipe the raw PCM data to an AudioTrack Our target devices so far are Droid and Nexus One. Everything works great on Nexus One, but the MP3 decode is too slow on Droid. The audio playback starts to skip if we put the Droid under load. We are not permitted to decode the MP3 data to SD card, but I know that's not our problem anyways. We didn't write our own MP3 decoder, but used MPADEC (http://sourceforge.net/projects/mpadec/). It's free and was easy to integrate with our program. We compile it with the NDK. After exhaustive analysis with various profiling tools, we're convinced that it's this decoder that is falling behind. Here's the options we're thinking about: Find another MP3 decoder that we can compile with the Android NDK. This MP3 decoder would have to be either optimized to run on mobile ARM devices or maybe use integer-only math or some other optimizations to increase performance. Since the built-in Android MediaPlayer service will take URLs, we might be able to implement a tiny HTTP server in our program and serve the MediaPlayer with the decrypted MP3s. That way we can take advantage of the built-in MP3 decoder. Get access to the built-in MP3 decoder through the NDK. I don't know if this is possible. Does anyone have any suggestions on what we can do to speed up our MP3 decoding? -- Rob Sz

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  • Can aptitude for learning Programming paradigms be influenced by culture or native language's gramma

    - by DVK
    It is well known that different people have different aptitudes regarding various programming paradigms (e.g. some people have trouble learning non-procedural, especially functional languages. Some people have trouble understanding pointers - see Joel Spolsky's blog for musings on that. Some people have trouble grasping recursion). I was recently reading about a study that looked at how the grammar of someone's native language affected their speed of learning math. Can't find that article now but a quick googling found this reference. That led me to wondering whether someone's native culture or first language might affect their aptitude towards various programming paradigms. I'm more curious about positive influences - e.g. some trait that make it easier/faster for someone to learn a particular paradigm, for example native language grammar being very recursion-oriented. To be clear, I'm looking for how culture/language grammare may affect the difference between aptitude of the same person towards various paradigms as opposed to how it affects overall aptitude towards programming between different persons. Important: the only answers I'm interested in are either references to scientific studies, or personal observations from someone intimately familiar with a particular culture/language, including from their own experience. E.g. I'm not interested in your opinion of how Chinese being your first language affects anything unless you speak Chinese or worked with extremely large set of Chinese-native programmers extensively. I'm OK with your guesstimates not based on scientific studies, but please be sure to supply your reasoning about plausible causes of your observation. I'm not interested in culture-bashing (any such commends will be deleted or flagged for deletion). I'm also not particularly interested in culture-building - we all know Linus is from Finland and Tetris was written in Russia and Larry Wall is an American. Any culture/nation can produce a brilliant mind in any discipline. I'm interested in averages.

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  • Parsing concatenated, non-delimited XML messages from TCP-stream using C#

    - by thaller
    I am trying to parse XML messages which are send to my C# application over TCP. Unfortunately, the protocol can not be changed and the XML messages are not delimited and no length prefix is used. Moreover the character encoding is not fixed but each message starts with an XML declaration <?xml>. The question is, how can i read one XML message at a time, using C#. Up to now, I tried to read the data from the TCP stream into a byte array and use it through a MemoryStream. The problem is, the buffer might contain more than one XML messages or the first message may be incomplete. In these cases, I get an exception when trying to parse it with XmlReader.Read or XmlDocument.Load, but unfortunately the XmlException does not really allow me to distinguish the problem (except parsing the localized error string). I tried using XmlReader.Read and count the number of Element and EndElement nodes. That way I know when I am finished reading the first, entire XML message. However, there are several problems. If the buffer does not yet contain the entire message, how can I distinguish the XmlException from an actually invalid, non-well-formed message? In other words, if an exception is thrown before reading the first root EndElement, how can I decide whether to abort the connection with error, or to collect more bytes from the TCP stream? If no exception occurs, the XmlReader is positioned at the start of the root EndElement. Casting the XmlReader to IXmlLineInfo gives me the current LineNumber and LinePosition, however it is not straight forward to get the byte position where the EndElement really ends. In order to do that, I would have to convert the byte array into a string (with the encoding specified in the XML declaration), seek to LineNumber,LinePosition and convert that back to the byte offset. I try to do that with StreamReader.ReadLine, but the stream reader gives no public access to the current byte position. All this seams very inelegant and non robust. I wonder if you have ideas for a better solution. Thank you. EDIT: I looked around and think that the situation is as follows (I might be wrong, corrections are welcome): I found no method so that the XmlReader can continue parsing a second XML message (at least not, if the second message has an XmlDeclaration). XmlTextReader.ResetState could do something similar, but for that I would have to assume the same encoding for all messages. Therefor I could not connect the XmlReader directly to the TcpStream. After closing the XmlReader, the buffer is not positioned at the readers last position. So it is not possible to close the reader and use a new one to continue with the next message. I guess the reason for this is, that the reader could not successfully seek on every possible input stream. When XmlReader throws an exception it can not be determined whether it happened because of an premature EOF or because of a non-wellformed XML. XmlReader.EOF is not set in case of an exception. As workaround I derived my own MemoryBuffer, which returns the very last byte as a single byte. This way I know that the XmlReader was really interested in the last byte and the following exception is likely due to a truncated message (this is kinda sloppy, in that it might not detect every non-wellformed message. However, after appending more bytes to the buffer, sooner or later the error will be detected. I could cast my XmlReader to the IXmlLineInfo interface, which gives access to the LineNumber and the LinePosition of the current node. So after reading the first message I remember these positions and use it to truncate the buffer. Here comes the really sloppy part, because I have to use the character encoding to get the byte position. I am sure you could find test cases for the code below where it breaks (e.g. internal elements with mixed encoding). But up to now it worked for all my tests. The parser class follows here -- may it be useful (I know, its very far from perfect...) class XmlParser { private byte[] buffer = new byte[0]; public int Length { get { return buffer.Length; } } // Append new binary data to the internal data buffer... public XmlParser Append(byte[] buffer2) { if (buffer2 != null && buffer2.Length > 0) { // I know, its not an efficient way to do this. // The EofMemoryStream should handle a List<byte[]> ... byte[] new_buffer = new byte[buffer.Length + buffer2.Length]; buffer.CopyTo(new_buffer, 0); buffer2.CopyTo(new_buffer, buffer.Length); buffer = new_buffer; } return this; } // MemoryStream which returns the last byte of the buffer individually, // so that we know that the buffering XmlReader really locked at the last // byte of the stream. // Moreover there is an EOF marker. private class EofMemoryStream: Stream { public bool EOF { get; private set; } private MemoryStream mem_; public override bool CanSeek { get { return false; } } public override bool CanWrite { get { return false; } } public override bool CanRead { get { return true; } } public override long Length { get { return mem_.Length; } } public override long Position { get { return mem_.Position; } set { throw new NotSupportedException(); } } public override void Flush() { mem_.Flush(); } public override long Seek(long offset, SeekOrigin origin) { throw new NotSupportedException(); } public override void SetLength(long value) { throw new NotSupportedException(); } public override void Write(byte[] buffer, int offset, int count) { throw new NotSupportedException(); } public override int Read(byte[] buffer, int offset, int count) { count = Math.Min(count, Math.Max(1, (int)(Length - Position - 1))); int nread = mem_.Read(buffer, offset, count); if (nread == 0) { EOF = true; } return nread; } public EofMemoryStream(byte[] buffer) { mem_ = new MemoryStream(buffer, false); EOF = false; } protected override void Dispose(bool disposing) { mem_.Dispose(); } } // Parses the first xml message from the stream. // If the first message is not yet complete, it returns null. // If the buffer contains non-wellformed xml, it ~should~ throw an exception. // After reading an xml message, it pops the data from the byte array. public Message deserialize() { if (buffer.Length == 0) { return null; } Message message = null; Encoding encoding = Message.default_encoding; //string xml = encoding.GetString(buffer); using (EofMemoryStream sbuffer = new EofMemoryStream (buffer)) { XmlDocument xmlDocument = null; XmlReaderSettings settings = new XmlReaderSettings(); int LineNumber = -1; int LinePosition = -1; bool truncate_buffer = false; using (XmlReader xmlReader = XmlReader.Create(sbuffer, settings)) { try { // Read to the first node (skipping over some element-types. // Don't use MoveToContent here, because it would skip the // XmlDeclaration too... while (xmlReader.Read() && (xmlReader.NodeType==XmlNodeType.Whitespace || xmlReader.NodeType==XmlNodeType.Comment)) { }; // Check for XML declaration. // If the message has an XmlDeclaration, extract the encoding. switch (xmlReader.NodeType) { case XmlNodeType.XmlDeclaration: while (xmlReader.MoveToNextAttribute()) { if (xmlReader.Name == "encoding") { encoding = Encoding.GetEncoding(xmlReader.Value); } } xmlReader.MoveToContent(); xmlReader.Read(); break; } // Move to the first element. xmlReader.MoveToContent(); // Read the entire document. xmlDocument = new XmlDocument(); xmlDocument.Load(xmlReader.ReadSubtree()); } catch (XmlException e) { // The parsing of the xml failed. If the XmlReader did // not yet look at the last byte, it is assumed that the // XML is invalid and the exception is re-thrown. if (sbuffer.EOF) { return null; } throw e; } { // Try to serialize an internal data structure using XmlSerializer. Type type = null; try { type = Type.GetType("my.namespace." + xmlDocument.DocumentElement.Name); } catch (Exception e) { // No specialized data container for this class found... } if (type == null) { message = new Message(); } else { // TODO: reuse the serializer... System.Xml.Serialization.XmlSerializer ser = new System.Xml.Serialization.XmlSerializer(type); message = (Message)ser.Deserialize(new XmlNodeReader(xmlDocument)); } message.doc = xmlDocument; } // At this point, the first XML message was sucessfully parsed. // Remember the lineposition of the current end element. IXmlLineInfo xmlLineInfo = xmlReader as IXmlLineInfo; if (xmlLineInfo != null && xmlLineInfo.HasLineInfo()) { LineNumber = xmlLineInfo.LineNumber; LinePosition = xmlLineInfo.LinePosition; } // Try to read the rest of the buffer. // If an exception is thrown, another xml message appears. // This way the xml parser could tell us that the message is finished here. // This would be prefered as truncating the buffer using the line info is sloppy. try { while (xmlReader.Read()) { } } catch { // There comes a second message. Needs workaround for trunkating. truncate_buffer = true; } } if (truncate_buffer) { if (LineNumber < 0) { throw new Exception("LineNumber not given. Cannot truncate xml buffer"); } // Convert the buffer to a string using the encoding found before // (or the default encoding). string s = encoding.GetString(buffer); // Seek to the line. int char_index = 0; while (--LineNumber > 0) { // Recognize \r , \n , \r\n as newlines... char_index = s.IndexOfAny(new char[] {'\r', '\n'}, char_index); // char_index should not be -1 because LineNumber>0, otherwise an RangeException is // thrown, which is appropriate. char_index++; if (s[char_index-1]=='\r' && s.Length>char_index && s[char_index]=='\n') { char_index++; } } char_index += LinePosition - 1; var rgx = new System.Text.RegularExpressions.Regex(xmlDocument.DocumentElement.Name + "[ \r\n\t]*\\>"); System.Text.RegularExpressions.Match match = rgx.Match(s, char_index); if (!match.Success || match.Index != char_index) { throw new Exception("could not find EndElement to truncate the xml buffer."); } char_index += match.Value.Length; // Convert the character offset back to the byte offset (for the given encoding). int line1_boffset = encoding.GetByteCount(s.Substring(0, char_index)); // remove the bytes from the buffer. buffer = buffer.Skip(line1_boffset).ToArray(); } else { buffer = new byte[0]; } } return message; } }

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  • Drag Panel Extender in Ajax?

    - by Surya sasidhar
    hi, i am working on dragpanel extender i write the code for drag panel, it is coming nice but when i drag the panel it going back to the same position where it is initially. This is my code... Untitled Page <style type="text/css"> .outerPanel { border: solid 1px #C0C0C0; background-color: #e1e1e1; width: 200px; height: 300px; z-index:20; padding: 2px; } .dragPanel { border: solid 1px #FFFFFF; background-color: #C0C0C0; width: 194px; height: 15px; color: #FFFFFF; font-weight:bold; padding: 2px; cursor: move; } function setBodyHeightToContentHeight() { document.body.style.height = Math.max(document.documentElement.scrollHeight, document.body.scrollHeight) + "px"; } setBodyHeightToContentHeight(); // Uncomment the line below if you are having problem while resizing the browser window. window.attachEvent('onresize', setBodyHeightToContentHeight); <asp:Panel ID="Panel1" runat="server" CssClass="outerPanel"> <asp:Panel ID="Panel2" runat="server" CssClass="dragPanel"> <b>Dragable Panel</b> </asp:Panel> <p> Surya Sasidhar surya sasidhar Surya Sasidhar surya sasidhar Surya sasidhar surya sasidhar </p> <cc1:DragPanelExtender ID="DragPanelExtender1" TargetControlID="Panel1" DragHandleID ="Panel2" runat="server"> </cc1:DragPanelExtender> </div> </form> and it is ging some javascript error like object required

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