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  • What issues lead people to use Japanese-specific encodings rather than Unicode?

    - by Nicolas Raoul
    At work I come across a lot of Japanese text files in Shift-JIS and other encodings. It causes many mojibake (unreadable character) problems for all computer users. Unicode was intended to solve this sort of problem by defining a single character set for all languages, and the UTF-8 serialization is recommended for use on the Internet. So why doesn't everybody switch from Japanese-specific encodings to UTF-8? What issues with or disadvantages of UTF-8 are holding people back? EDIT: The W3C lists some known problems with Unicode, could this be a reason too?

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  • samplerCubeShadow and texture offset

    - by Irbis
    I use sampler2DShadow when accessing a single shadow map. I create PCF in this way: result += textureProjOffset(ShadowSampler, ShadowCoord, ivec2(-1,-1)); result += textureProjOffset(ShadowSampler, ShadowCoord, ivec2(-1,1)); result += textureProjOffset(ShadowSampler, ShadowCoord, ivec2(1,1)); result += textureProjOffset(ShadowSampler, ShadowCoord, ivec2(1,-1)); result = result * 0.25; For a cube map I use samplerCubeShadow: result = texture(ShadowCubeSampler, vec4(normalize(position), depth)); How to adopt above PCF when accessing a cube map ?

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  • Breaking 1NF to model subset constraints. Does this sound sane?

    - by Chris Travers
    My first question here. Appologize if it is in the wrong forum but this seems pretty conceptual. I am looking at doing something that goes against conventional wisdom and want to get some feedback as to whether this is totally insane or will result in problems, so critique away! I am on PostgreSQL 9.1 but may be moving to 9.2 for this part of this project. To re-iterate: Does it seem sane to break 1NF in this way? I am not looking for debugging code so much as where people see problems that this might lead. The Problem In double entry accounting, financial transactions are journal entries with an arbitrary number of lines. Each line has either a left value (debit) or a right value (credit) which can be modelled as a single value with negatives as debits and positives as credits or vice versa. The sum of all debits and credits must equal zero (so if we go with a single amount field, sum(amount) must equal zero for each financial journal entry). SQL-based databases, pretty much required for this sort of work, have no way to express this sort of constraint natively and so any approach to enforcing it in the database seems rather complex. The Write Model The journal entries are append only. There is a possibility we will add a delete model but it will be subject to a different set of restrictions and so is not applicable here. If and when we allow deletes, we will probably do them using a simple ON DELETE CASCADE designation on the foreign key, and require that deletes go through a dedicated stored procedure which can enforce the other constraints. So inserts and selects have to be accommodated but updates and deletes do not for this task. My Proposed Solution My proposed solution is to break first normal form and model constraints on arrays of tuples, with a trigger that breaks the rows out into another table. CREATE TABLE journal_line ( entry_id bigserial primary key, account_id int not null references account(id), journal_entry_id bigint not null, -- adding references later amount numeric not null ); I would then add "table methods" to extract debits and credits for reporting purposes: CREATE OR REPLACE FUNCTION debits(journal_line) RETURNS numeric LANGUAGE sql IMMUTABLE AS $$ SELECT CASE WHEN $1.amount < 0 THEN $1.amount * -1 ELSE NULL END; $$; CREATE OR REPLACE FUNCTION credits(journal_line) RETURNS numeric LANGUAGE sql IMMUTABLE AS $$ SELECT CASE WHEN $1.amount > 0 THEN $1.amount ELSE NULL END; $$; Then the journal entry table (simplified for this example): CREATE TABLE journal_entry ( entry_id bigserial primary key, -- no natural keys :-( journal_id int not null references journal(id), date_posted date not null, reference text not null, description text not null, journal_lines journal_line[] not null ); Then a table method and and check constraints: CREATE OR REPLACE FUNCTION running_total(journal_entry) returns numeric language sql immutable as $$ SELECT sum(amount) FROM unnest($1.journal_lines); $$; ALTER TABLE journal_entry ADD CONSTRAINT CHECK (((journal_entry.running_total) = 0)); ALTER TABLE journal_line ADD FOREIGN KEY journal_entry_id REFERENCES journal_entry(entry_id); And finally we'd have a breakout trigger: CREATE OR REPLACE FUNCTION je_breakout() RETURNS TRIGGER LANGUAGE PLPGSQL AS $$ BEGIN IF TG_OP = 'INSERT' THEN INSERT INTO journal_line (journal_entry_id, account_id, amount) SELECT NEW.id, account_id, amount FROM unnest(NEW.journal_lines); RETURN NEW; ELSE RAISE EXCEPTION 'Operation Not Allowed'; END IF; END; $$; And finally CREATE TRIGGER AFTER INSERT OR UPDATE OR DELETE ON journal_entry FOR EACH ROW EXECUTE_PROCEDURE je_breaout(); Of course the example above is simplified. There will be a status table that will track approval status allowing for separation of duties, etc. However the goal here is to prevent unbalanced transactions. Any feedback? Does this sound entirely insane? Standard Solutions? In getting to this point I have to say I have looked at four different current ERP solutions to this problems: Represent every line item as a debit and a credit against different accounts. Use of foreign keys against the line item table to enforce an eventual running total of 0 Use of constraint triggers in PostgreSQL Forcing all validation here solely through the app logic. My concerns are that #1 is pretty limiting and very hard to audit internally. It's not programmer transparent and so it strikes me as being difficult to work with in the future. The second strikes me as being very complex and required a series of contraints and foreign keys against self to make work, and therefore it strikes me as complex, hard to sort out at least in my mind, and thus hard to work with. The fourth could be done as we force all access through stored procedures anyway and this is the most common solution (have the app total things up and throw an error otherwise). However, I think proof that a constraint is followed is superior to test cases, and so the question becomes whether this in fact generates insert anomilies rather than solving them. If this is a solved problem it isn't the case that everyone agrees on the solution....

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  • Know a little of a lot or a lot of a little? [closed]

    - by Jeff V
    Possible Duplicate: Is it better to specialize in a single field I like, or expand into other fields to broaden my horizons? My buddy and I who have been programming for 13 years or so were talking this morning and a question that came up was is it better to know a little of a lot (i.e. web, desktop, VB.Net, C#, jQuery, PHP, Java etc.) or is it better to know a lot of a little (meaning expert in something). The context of this question is what makes someone a senior programmer? Is it someone that has been around the block a few times and has been in many different situations or one that is locked in to a specific technology that is super knowledgeable in that one technology? I see pro's and con's of both scenarios.. Just wondering what others thought.

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  • How many tiers should my models have in a DB driven web app?

    - by Hanno Fietz
    In my experience, the "Model" in MVC is often not really a single layer. I would regularly have "backend" models and "frontend" models, where the backend ones would have properties that I want to hide from the UI code, and the frontend ones have derived or composite properties which are more meaningful in the context of the UI. Recently, I have started to introduce a third layer in between when database normalization created tables that did not really match the conceptual domain objects anymore. In those projects I have model classes that are equivalent with the DB structure, these become components of objects that represent the domain model, and finally these are filtered and amended for displaying information to the user. Are there patterns or guidelines for how, when and why to organize the data model across application layers?

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  • How do you set up PhysFS for use in a game?

    - by ThePlan
    After my recent question on GD I've been advised to use PhysFS to pack all my game data in 1 file. So I have, and the decission wasn't light, because I've tried out every library in my answers but none contained a single good tutorial whatsoever, in fact PhysFS is the poorest documented library I've ever seen. After attempting to set up PhysFS in my game I realized it's not as simple as adding the headers to the project, it appears something much more complicated, in fact after my first attempt to install PhysFS the compiler ran out of memory to display errors, it reached the critical count of 50 errors. So basically what I'm asking here is: How can I set up PhysFS on my game? I'm using Code::Blocks IDE on Windows XP SP3;

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  • Developing Schema Compare for Oracle (Part 5): Query Snapshots

    - by Simon Cooper
    If you've emailed us about a bug you've encountered with the EAP or beta versions of Schema Compare for Oracle, we probably asked you to send us a query snapshot of your databases. Here, I explain what a query snapshot is, and how it helps us fix your bug. Problem 1: Debugging users' bug reports When we started the Schema Compare project, we knew we were going to get problems with users' databases - configurations we hadn't considered, features that weren't installed, unicode issues, wierd dependencies... With SQL Compare, users are generally happy to send us a database backup that we can restore using a single RESTORE DATABASE command on our test servers and immediately reproduce the problem. Oracle, on the other hand, would be a lot more tricky. As Oracle generally has a 1-to-1 mapping between instances and databases, any databases users sent would have to be restored to their own instance. Furthermore, the number of steps required to get a properly working database, and the size of most oracle databases, made it infeasible to ask every customer who came across a bug during our beta program to send us their databases. We also knew that there would be lots of issues with data security that would make it hard to get backups. So we needed an easier way to be able to debug customers issues and sort out what strange schema data Oracle was returning. Problem 2: Test execution time Another issue we knew we would have to solve was the execution time of the tests we would produce for the Schema Compare engine. Our initial prototype showed that querying the data dictionary for schema information was going to be slow (at least 15 seconds per database), and this is generally proportional to the size of the database. If you're running thousands of tests on the same databases, each one registering separate schemas, not only would the tests would take hours and hours to run, but the test servers would be hammered senseless. The solution To solve these, we needed to be able to populate the schema of a database without actually connecting to it. Well, the IDataReader interface is the primary way we read data from an Oracle server. The data dictionary queries we use return their data in terms of simple strings and numbers, which we then process and reconstruct into an object model, and the results of these queries are identical for identical schemas. So, we can record the raw results of the queries once, and then replay these results to construct the same object model as many times as required without needing to actually connect to the original database. This is what query snapshots do. They are binary files containing the raw unprocessed data we get back from the oracle server for all the queries we run on the data dictionary to get schema information. The core of the query snapshot generation takes the results of the IDataReader we get from running queries on Oracle, and passes the row data to a BinaryWriter that writes it straight to a file. The query snapshot can then be replayed to create the same object model; when the results of a specific query is needed by the population code, we can simply read the binary data stored in the file on disk and present it through an IDataReader wrapper. This is far faster than querying the server over the network, and allows us to run tests in a reasonable time. They also allow us to easily debug a customers problem; using a simple snapshot generation program, users can generate a query snapshot that could be sent along with a bug report that we can immediately replay on our machines to let us debug the issue, rather than having to obtain database backups and restore databases to test systems. There are also far fewer problems with data security; query snapshots only contain schema information, which is generally less sensitive than table data. Query snapshots implementation However, actually implementing such a feature did have a couple of 'gotchas' to it. My second blog post detailed the development of the dependencies algorithm we use to ensure we get all the dependencies in the database, and that algorithm uses data from both databases to find all the needed objects - what database you're comparing to affects what objects get populated from both databases. We get information on these additional objects using an appropriate WHERE clause on all the population queries. So, in order to accurately replay the results of querying the live database, the query snapshot needs to be a snapshot of a comparison of two databases, not just populating a single database. Furthermore, although the code population queries (eg querying all_tab_cols to get column information) can simply be passed straight from the IDataReader to the BinaryWriter, we need to hook into and run the live dependencies algorithm while we're creating the snapshot to ensure we get the same WHERE clauses, and the same query results, as if we were populating straight from a live system. We also need to store the results of the dependencies queries themselves, as the resulting dependency graph is stored within the OracleDatabase object that is produced, and is later used to help order actions in synchronization scripts. This is significantly helped by the dependencies algorithm being a deterministic algorithm - given the same input, it will always return the same output. Therefore, when we're replaying a query snapshot, and processing dependency information, we simply have to return the results of the queries in the order we got them from the live database, rather than trying to calculate the contents of all_dependencies on the fly. Query snapshots are a significant feature in Schema Compare that really helps us to debug problems with the tool, as well as making our testers happier. Although not really user-visible, they are very useful to the development team to help us fix bugs in the product much faster than we otherwise would be able to.

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  • What constitutes proper use of threads in programming?

    - by Smith
    I am tired of hearing people recommend that you should use only one thread per process, while many programs use up to 100 per process! take for example some common programs vb.net ide uses about 25 thread when not debugging System uses about 100 chrome uses about 19 Avira uses more than about 50 Any time I post a thread related question, I am reminded almost every time that I should not use more that one thread per process, and all the programs I mention above are ruining on my system with a single processor. What constitutes proper use of threads in programming? Please make general comment, but I'd prefer .NET framework thanks EDIT changed processor to process

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  • How would you represent an object that can be of multiple types, when storing it as a document in MongoDB?

    - by blueberryfields
    Somewhat related to this question, say that I have an object category which, depending on which type of object I have, has different restrictions on what it contains. (if you can reword the previous sentence to make more sense I'd appreciate it) For example var SomeSchema = new Schema({ _id: ObjectID, [... large number of common fields ...] type: //Restricted somehow to members of a fixed array data: //depending on type, this might be restricted - sometimes an integer, sometimes array, etc... }); What's the idiosyncratic method for defining this type of schema? Is it appropriate to define a single schema, and handle the types inside of it's members, or am I better off with separate schema for each type?

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  • Dynamic tests with mstest and T4

    - by Victor Hurdugaci
    If you used mstest and NUnit you might be aware of the fact that the former doesn't support dynamic, data driven test cases. For example, the following scenario cannot be achieved with the out-of-box mstest: given a dataset, create distinct test cases for each entry in it, using a predefined generic test case. The best result that can be achieved using mstest is a single testcase that will iterate through the dataset. There is one disadvantage: if the test fails for one entry in the dataset, the whole test case fails. So, in order to overcome the previously mentioned limitation, I decided to create a text template that will generate the test cases for me. As an example, I will write some tests for an integer multiplication function that has 2 bugs in it: Read more >> [Cross post from victorhurdugaci.com]

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  • Movement of body after applying weld joint

    - by ved
    I have two rectangular bodies. I've applied Weldjoint successfully on these bodies. I want to move that joined body by applying linear impulse. After weld joint, these two bodies becomes single body right? How do I apply force/impulse on the joined body? I am using Box2D with LibGDX. I've tried this: polygon1.applyLinearImpulse(new Vector2(-5, 0), polygon1.getWorldCenter(), true); I thought that if I move polygon1 then polygon2 will also move due to my weld joint but it is not working properly. Why don't they move together after being welded?

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  • WebLogic Application Server: free for developers!

    - by Bruno.Borges
    Great news! Oracle WebLogic Server is now free for developers! What does this mean for you? That you as a developer are permited to: "[...] deploy the programs only on your single developer desktop computer (of any type, including physical, virtual or remote virtual), to be used and accessed by only (1) named developer." But the most interesting part of the license change is this one: "You may continue to develop, test, prototype and demonstrate your application with the programs under this license after you have deployed the application for any internal data processing, commercial or production purposes" (Read the full license agreement here) If you want to take advantage of this licensing change and start developing Java EE applications with the #1 Application Server in the world, read now the previous post, How To Install WebLogic Zip on Linux!

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  • How do I implement Unreal-like object serialization?

    - by MrWiggels
    Recently, I've been working on the core of my engine, and as I'm moving forward I find myself developing throwaway code to read files and simple data into the engine. This got me thinking about how I should implement a file management system. After a bit of googleing I came across the Unreal Package format, and boy does it look like the perfect one. I think it's good because the way how it allows you to separate different assets into different packages and allow something like a level to reference the different packages. I was just wondering, is this possible with C#? Because the built-in serialization API in .NET does not seem to support any form of this, only reading and writing to a single file.

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  • Performance triage

    - by Dave
    Folks often ask me how to approach a suspected performance issue. My personal strategy is informed by the fact that I work on concurrency issues. (When you have a hammer everything looks like a nail, but I'll try to keep this general). A good starting point is to ask yourself if the observed performance matches your expectations. Expectations might be derived from known system performance limits, prototypes, and other software or environments that are comparable to your particular system-under-test. Some simple comparisons and microbenchmarks can be useful at this stage. It's also useful to write some very simple programs to validate some of the reported or expected system limits. Can that disk controller really tolerate and sustain 500 reads per second? To reduce the number of confounding factors it's better to try to answer that question with a very simple targeted program. And finally, nothing beats having familiarity with the technologies that underlying your particular layer. On the topic of confounding factors, as our technology stacks become deeper and less transparent, we often find our own technology working against us in some unexpected way to choke performance rather than simply running into some fundamental system limit. A good example is the warm-up time needed by just-in-time compilers in Java Virtual Machines. I won't delve too far into that particular hole except to say that it's rare to find good benchmarks and methodology for java code. Another example is power management on x86. Power management is great, but it can take a while for the CPUs to throttle up from low(er) frequencies to full throttle. And while I love "turbo" mode, it makes benchmarking applications with multiple threads a chore as you have to remember to turn it off and then back on otherwise short single-threaded runs may look abnormally fast compared to runs with higher thread counts. In general for performance characterization I disable turbo mode and fix the power governor at "performance" state. Another source of complexity is the scheduler, which I've discussed in prior blog entries. Lets say I have a running application and I want to better understand its behavior and performance. We'll presume it's warmed up, is under load, and is an execution mode representative of what we think the norm would be. It should be in steady-state, if a steady-state mode even exists. On Solaris the very first thing I'll do is take a set of "pstack" samples. Pstack briefly stops the process and walks each of the stacks, reporting symbolic information (if available) for each frame. For Java, pstack has been augmented to understand java frames, and even report inlining. A few pstack samples can provide powerful insight into what's actually going on inside the program. You'll be able to see calling patterns, which threads are blocked on what system calls or synchronization constructs, memory allocation, etc. If your code is CPU-bound then you'll get a good sense where the cycles are being spent. (I should caution that normal C/C++ inlining can diffuse an otherwise "hot" method into other methods. This is a rare instance where pstack sampling might not immediately point to the key problem). At this point you'll need to reconcile what you're seeing with pstack and your mental model of what you think the program should be doing. They're often rather different. And generally if there's a key performance issue, you'll spot it with a moderate number of samples. I'll also use OS-level observability tools to lock for the existence of bottlenecks where threads contend for locks; other situations where threads are blocked; and the distribution of threads over the system. On Solaris some good tools are mpstat and too a lesser degree, vmstat. Try running "mpstat -a 5" in one window while the application program runs concurrently. One key measure is the voluntary context switch rate "vctx" or "csw" which reflects threads descheduling themselves. It's also good to look at the user; system; and idle CPU percentages. This can give a broad but useful understanding if your threads are mostly parked or mostly running. For instance if your program makes heavy use of malloc/free, then it might be the case you're contending on the central malloc lock in the default allocator. In that case you'd see malloc calling lock in the stack traces, observe a high csw/vctx rate as threads block for the malloc lock, and your "usr" time would be less than expected. Solaris dtrace is a wonderful and invaluable performance tool as well, but in a sense you have to frame and articulate a meaningful and specific question to get a useful answer, so I tend not to use it for first-order screening of problems. It's also most effective for OS and software-level performance issues as opposed to HW-level issues. For that reason I recommend mpstat & pstack as my the 1st step in performance triage. If some other OS-level issue is evident then it's good to switch to dtrace to drill more deeply into the problem. Only after I've ruled out OS-level issues do I switch to using hardware performance counters to look for architectural impediments.

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  • ESSO Webcast Replay with Live Q&A

    - by B Shashikumar
    In our ESSO webcast on Oct 19th, we discussed how Oracle Enterprise Single-Sign On Suite can not only eliminate your password reset and helpdesk headaches but also offers a healthy ROI which enterprises just cannot overlook. In our webcast we discussed how Oracle ESSO Suite can deliver an ROI of 140% within the first year of deployment. Due to popular demand, we are now doing a re-broadcast of this webcast in the European time zone. The webcast will be followed by live Q&A. Matt Berzinski, Product Manager for Oracle ESSO Suite will be on air to answer all of your ESSO and Identity Management questions.  Join us on this webcast to find out how Oracle ESSO Suite Plus can deliver quick wins for your organization. Register here for this webcast.

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  • How should I handle using two databases with a legacy PHP application?

    - by Toby Allen
    I have a legacy PHP application that was written in 2004 and uses MSSQL as a database backend. At this stage MSSQL is still supported by PHP but only just via a Microsoft driver. I have looked at converting to mysql via automated tools, which work quite well, but I have quite complex views which need a lot of individual work to convert. I don't have a great deal of time to do this. Many tools I wish to use and frameworks I would like to move the application to, don't support MSSQL, so I was considering adding new features using a new mysql database and wondered if anyone had opinions on the pros and cons of using two seperate database backends in a single application?

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  • Simple solution now to a problem from 8 years ago. Use SQL windowing function

    - by Kevin Shyr
    Originally posted on: http://geekswithblogs.net/LifeLongTechie/archive/2014/06/10/simple-solution-now-to-a-problem-from-8-years-ago.aspxI remember having this problem 8 years ago. We had to find the top 5 donor per month and send out some awards. The SQL we came up with was clunky and had lots of limitation (can only do one year at a time), then switch the where clause and go again. Fast forward 8 years, I got a similar problem where we had to find the top 3 combination of 2 fields for every single day. And the solution is this elegant: SELECT CAST(eff_dt AS DATE) AS "RecordDate" , status_cd , nbr , COUNT(*) AS occurance , ROW_NUMBER() OVER (PARTITION BY CAST(eff_dt AS DATE) ORDER BY COUNT(*) DESC) RowNum FROM table1 WHERE RowNum < 4 GROUP BY CAST(eff_dt AS DATE) , status_cd , nbr If only I had this 8 years ago. :) Life is good now!

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  • How i can sign and/or group a specific set of vertices in a 3D file container like OBJ ? - in Blender

    - by user827992
    I would like to export a 3D model with each part having a name or a label if you will. For example i would like to export a model of an human body and name each part in specifics vertex groups like: left hand, right hand, right foot, head, ears, ... and you got the idea; so i can have a single 3D model that i can explode in various parts if needed. If there is a better technique about how to mark vertex groups in a 3D file please share your solution. As 3D editor i use Blender.

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  • J2ME character animation with multiple sprite sheets

    - by Alex
    I'm working on a J2ME game and I want to have walking animations. Each direction of walking has a separate sprite sheet (i.e. one for walking up, one for walking right etc), I also have a static idle image for each direction held together in a single file. I've tried to hold an array of sprites in my player class and then just drawing the sprite corresponding to the current direction, but this doesn't seem to work. I'm aware that if I combine all the animations into one sprite sheet I could set up different animation sequences, but I want to be able to do it with separate images for each animation. Is there a way that anyone knows of to achieve this? And ideally without too much extra code (as opposed to combining the sprites into one sheet)

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  • 'dock' working in simple words

    - by Shirish11
    I would like to know the idea behind the working of 'docking' in applications. I have worked with applications where components from individual forms are docked on a single main form to provide the necessary GUI. But I don't have any idea whats happening in the background. According to Wikipedia A dock is a graphical user interface element that typically provides the user with a way of launching, switching between, and monitoring running programs or applications. Now I am a bit confused if it is some component or an event or a property or something else. EDIT : The applications was developed in Delphi on windows platform. There is something more in Delphi (manual dock and automatic dock).

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  • Running a compiled Java program

    - by Roshan George
    I have a question on a compiled Java program that I have written. I have a Java file that has three classes defined within it. When I compiled the program I got a total of four classes. How do I make this into a form where I can run my application just by clicking an icon or something, or by issuing just a single command. For example, if I make it as an exe file, it could run only on Windows, how do I make it into a form compatible with all Oses. And hoe?

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  • Install Ubuntu 12.04 LTS 64bit in Lenovo S205 Failed

    - by Zakiul Fuady
    I had ever installed Ubuntu 12.04 in Lenovo S205 twice, but it could not boot like an ordinary laptop. how i can fix this problem.? i tried to install dual boot. windows and Ubuntu. but it could not work properly. even, when i installed single boot. it could not too. installation was okay, but it could not boot to Ubuntu. just stuck in blank screen. like what I posted in my blog below http://fzakiul.wordpress.com/2012/05/11/lenovo-ideapad-s205-vs-ubuntu/ extremely need a help.

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  • OpenGL ES 2. How do I Create a Basic Fading Streak Effect?

    - by dugla
    For the iPad app I am writing using OpenGL ES 2 I have a single quad - shaded using GLSL - that is dragged around the screen. Very basic. This works fine. But is rather boring. I want to increase the coolness a bit in the following way: when the user drags the quad it leaves a streak behind that fades over time. Continuous dragging would be a bit like a streaking comet across the night sky. What is the simplest way to implement this? Thanks.

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  • Defining the track in a 2D racing game

    - by Ivan
    I am designing a top-down racing game using canvas (html5) which takes a lot of inspiration from Micro Machines. In MM, cars can move off the track, but they are reset/destroyed if they go too far. My maths knowledge isn't great, so I'm finding it hard to separate 3D/complex concepts from those which are directly relevant to my situation. For example, I have seen "splines" mentioned, is this something I should read up on or is that overkill for a 2D game? Could I use a single path which defines the centre of the track and check a car's distance from this line? A second path might be required as a "racing line" for AI. Any advice on methods/techniques/terms to read up on would be greatly appreciated.

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  • Why do I get an exception when playing multiple sound instances?

    - by Boreal
    Right now, I'm adding a rudimentary sound engine to my game. So far, I am able to load in a WAV file and play it once, then free up the memory when I close the game. However, the game crashes with a nice ArgumentOutOfBoundsException when I try to play another sound instance. Specified argument was out of the range of valid values. Parameter name: readLength I'm following this tutorial pretty much exactly, but I still keep getting the aforementioned error. Here's my sound-related code. /// <summary> /// Manages all sound instances. /// </summary> public static class Audio { static XAudio2 device; static MasteringVoice master; static List<SoundInstance> instances; /// <summary> /// The XAudio2 device. /// </summary> internal static XAudio2 Device { get { return device; } } /// <summary> /// Initializes the audio device and master track. /// </summary> internal static void Initialize() { device = new XAudio2(); master = new MasteringVoice(device); instances = new List<SoundInstance>(); } /// <summary> /// Releases all XA2 resources. /// </summary> internal static void Shutdown() { foreach(SoundInstance i in instances) i.Dispose(); master.Dispose(); device.Dispose(); } /// <summary> /// Registers a sound instance with the system. /// </summary> /// <param name="instance">Sound instance</param> internal static void AddInstance(SoundInstance instance) { instances.Add(instance); } /// <summary> /// Disposes any sound instance that has stopped playing. /// </summary> internal static void Update() { List<SoundInstance> temp = new List<SoundInstance>(instances); foreach(SoundInstance i in temp) if(!i.Playing) { i.Dispose(); instances.Remove(i); } } } /// <summary> /// Loads sounds from various files. /// </summary> internal class SoundLoader { /// <summary> /// Loads a .wav sound file. /// </summary> /// <param name="format">The decoded format will be sent here</param> /// <param name="buffer">The data will be sent here</param> /// <param name="soundName">The path to the WAV file</param> internal static void LoadWAV(out WaveFormat format, out AudioBuffer buffer, string soundName) { WaveStream wave = new WaveStream(soundName); format = wave.Format; buffer = new AudioBuffer(); buffer.AudioData = wave; buffer.AudioBytes = (int)wave.Length; buffer.Flags = BufferFlags.EndOfStream; } } /// <summary> /// Manages the data for a single sound. /// </summary> public class Sound : IAsset { WaveFormat format; AudioBuffer buffer; /// <summary> /// Loads a sound from a file. /// </summary> /// <param name="soundName">The path to the sound file</param> /// <returns>Whether the sound loaded successfully</returns> public bool Load(string soundName) { if(soundName.EndsWith(".wav")) SoundLoader.LoadWAV(out format, out buffer, soundName); else return false; return true; } /// <summary> /// Plays the sound. /// </summary> public void Play() { Audio.AddInstance(new SoundInstance(format, buffer)); } /// <summary> /// Unloads the sound from memory. /// </summary> public void Unload() { buffer.Dispose(); } } /// <summary> /// Manages a single sound instance. /// </summary> public class SoundInstance { SourceVoice source; bool playing; /// <summary> /// Whether the sound is currently playing. /// </summary> public bool Playing { get { return playing; } } /// <summary> /// Starts a new instance of a sound. /// </summary> /// <param name="format">Format of the sound</param> /// <param name="buffer">Buffer holding sound data</param> internal SoundInstance(WaveFormat format, AudioBuffer buffer) { source = new SourceVoice(Audio.Device, format); source.BufferEnd += (s, e) => playing = false; source.Start(); source.SubmitSourceBuffer(buffer); // THIS IS WHERE THE EXCEPTION IS THROWN playing = true; } /// <summary> /// Releases memory used by the instance. /// </summary> internal void Dispose() { source.Dispose(); } } The exception occurs on line 156 when I am playing the sound: source.SubmitSourceBuffer(buffer);

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