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  • "Optimal" game loop for 2D side-scroller

    - by MrDatabase
    Is it possible to describe an "optimal" (in terms of performance) layout for a 2D side-scroller's game loop? In this context the "game loop" takes user input, updates the states of game objects and draws the game objects. For example having a GameObject base class with a deep inheritance hierarchy could be good for maintenance... you can do something like the following: foreach(GameObject g in gameObjects) g.update(); However I think this approach can create performance issues. On the other hand all game objects' data and functions could be global. Which would be a maintenance headache but might be closer to an optimally performing game loop. Any thoughts? I'm interested in practical applications of near optimal game loop structure... even if I get a maintenance headache in exchange for great performance.

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  • Extreme Optimization – Numerical Algorithm Support

    - by JoshReuben
    Function Delegates Many calculations involve the repeated evaluation of one or more user-supplied functions eg Numerical integration. The EO MathLib provides delegate types for common function signatures and the FunctionFactory class can generate new delegates from existing ones. RealFunction delegate - takes one Double parameter – can encapsulate most of the static methods of the System.Math class, as well as the classes in the Extreme.Mathematics.SpecialFunctions namespace: var sin = new RealFunction(Math.Sin); var result = sin(1); BivariateRealFunction delegate - takes two Double parameters: var atan2 = new BivariateRealFunction (Math.Atan2); var result = atan2(1, 2); TrivariateRealFunction delegate – represents a function takes three Double arguments ParameterizedRealFunction delegate - represents a function taking one Integer and one Double argument that returns a real number. The Pow method implements such a function, but the arguments need order re-arrangement: static double Power(int exponent, double x) { return ElementaryFunctions.Pow(x, exponent); } ... var power = new ParameterizedRealFunction(Power); var result = power(6, 3.2); A ComplexFunction delegate - represents a function that takes an Extreme.Mathematics.DoubleComplex argument and also returns a complex number. MultivariateRealFunction delegate - represents a function that takes an Extreme.Mathematics.LinearAlgebra.Vector argument and returns a real number. MultivariateVectorFunction delegate - represents a function that takes a Vector argument and returns a Vector. FastMultivariateVectorFunction delegate - represents a function that takes an input Vector argument and an output Matrix argument – avoiding object construction  The FunctionFactory class RealFromBivariateRealFunction and RealFromParameterizedRealFunction helper methods - transform BivariateRealFunction or a ParameterizedRealFunction into a RealFunction delegate by fixing one of the arguments, and treating this as a new function of a single argument. var tenthPower = FunctionFactory.RealFromParameterizedRealFunction(power, 10); var result = tenthPower(x); Note: There is no direct way to do this programmatically in C# - in F# you have partial value functions where you supply a subset of the arguments (as a travelling closure) that the function expects. When you omit arguments, F# generates a new function that holds onto/remembers the arguments you passed in and "waits" for the other parameters to be supplied. let sumVals x y = x + y     let sumX = sumVals 10     // Note: no 2nd param supplied.     // sumX is a new function generated from partially applied sumVals.     // ie "sumX is a partial application of sumVals." let sum = sumX 20     // Invokes sumX, passing in expected int (parameter y from original)  val sumVals : int -> int -> int val sumX : (int -> int) val sum : int = 30 RealFunctionsToVectorFunction and RealFunctionsToFastVectorFunction helper methods - combines an array of delegates returning a real number or a vector into vector or matrix functions. The resulting vector function returns a vector whose components are the function values of the delegates in the array. var funcVector = FunctionFactory.RealFunctionsToVectorFunction(     new MultivariateRealFunction(myFunc1),     new MultivariateRealFunction(myFunc2));  The IterativeAlgorithm<T> abstract base class Iterative algorithms are common in numerical computing - a method is executed repeatedly until a certain condition is reached, approximating the result of a calculation with increasing accuracy until a certain threshold is reached. If the desired accuracy is achieved, the algorithm is said to converge. This base class is derived by many classes in the Extreme.Mathematics.EquationSolvers and Extreme.Mathematics.Optimization namespaces, as well as the ManagedIterativeAlgorithm class which contains a driver method that manages the iteration process.  The ConvergenceTest abstract base class This class is used to specify algorithm Termination , convergence and results - calculates an estimate for the error, and signals termination of the algorithm when the error is below a specified tolerance. Termination Criteria - specify the success condition as the difference between some quantity and its actual value is within a certain tolerance – 2 ways: absolute error - difference between the result and the actual value. relative error is the difference between the result and the actual value relative to the size of the result. Tolerance property - specify trade-off between accuracy and execution time. The lower the tolerance, the longer it will take for the algorithm to obtain a result within that tolerance. Most algorithms in the EO NumLib have a default value of MachineConstants.SqrtEpsilon - gives slightly less than 8 digits of accuracy. ConvergenceCriterion property - specify under what condition the algorithm is assumed to converge. Using the ConvergenceCriterion enum: WithinAbsoluteTolerance / WithinRelativeTolerance / WithinAnyTolerance / NumberOfIterations Active property - selectively ignore certain convergence tests Error property - returns the estimated error after a run MaxIterations / MaxEvaluations properties - Other Termination Criteria - If the algorithm cannot achieve the desired accuracy, the algorithm still has to end – according to an absolute boundary. Status property - indicates how the algorithm terminated - the AlgorithmStatus enum values:NoResult / Busy / Converged (ended normally - The desired accuracy has been achieved) / IterationLimitExceeded / EvaluationLimitExceeded / RoundOffError / BadFunction / Divergent / ConvergedToFalseSolution. After the iteration terminates, the Status should be inspected to verify that the algorithm terminated normally. Alternatively, you can set the ThrowExceptionOnFailure to true. Result property - returns the result of the algorithm. This property contains the best available estimate, even if the desired accuracy was not obtained. IterationsNeeded / EvaluationsNeeded properties - returns the number of iterations required to obtain the result, number of function evaluations.  Concrete Types of Convergence Test classes SimpleConvergenceTest class - test if a value is close to zero or very small compared to another value. VectorConvergenceTest class - test convergence of vectors. This class has two additional properties. The Norm property specifies which norm is to be used when calculating the size of the vector - the VectorConvergenceNorm enum values: EuclidianNorm / Maximum / SumOfAbsoluteValues. The ErrorMeasure property specifies how the error is to be measured – VectorConvergenceErrorMeasure enum values: Norm / Componentwise ConvergenceTestCollection class - represent a combination of tests. The Quantifier property is a ConvergenceTestQuantifier enum that specifies how the tests in the collection are to be combined: Any / All  The AlgorithmHelper Class inherits from IterativeAlgorithm<T> and exposes two methods for convergence testing. IsValueWithinTolerance<T> method - determines whether a value is close to another value to within an algorithm's requested tolerance. IsIntervalWithinTolerance<T> method - determines whether an interval is within an algorithm's requested tolerance.

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  • Multiple Object Instantiation

    - by Ricky Baby
    I am trying to get my head around object oriented programming as it pertains to web development (more specifically PHP). I understand inheritance and abstraction etc, and know all the "buzz-words" like encapsulation and single purpose and why I should be doing all this. But my knowledge is falling short with actually creating objects that relate to the data I have in my database, creating a single object that a representative of a single entity makes sense, but what are the best practises when creating 100, 1,000 or 10,000 objects of the same type. for instance, when trying to display a list of the items, ideally I would like to be consistent with the objects I use, but where exactly should I run the query/get the data to populate the object(s) as running 10,000 queries seems wasteful. As an example, say I have a database of cats, and I want a list of all black cats, do I need to set up a FactoryObject which grabs the data needed for each cat from my database, then passes that data into each individual CatObject and returns the results in a array/object - or should I pass each CatObject it's identifier and let it populate itself in a separate query.

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  • Auto-Configuring SSIS Packages

    - by Davide Mauri
    SSIS Package Configurations are very useful to make packages flexible so that you can change objects properties at run-time and thus make the package configurable without having to open and edit it. In a complex scenario where you have dozen of packages (even in in the smallest BI project I worked on I had 50 packages), each package may have its own configuration needs. This means that each time you have to run the package you have to pass the correct Package Configuration. I usually use XML configuration files and I also force everyone that works with me to make sure that an object that is used in several packages has the same name in all package where it is used, in order to simplify configurations usage. Connection Managers are a good example of one of those objects. For example, all the packages that needs to access to the Data Warehouse database must have a Connection Manager named DWH. Basically we define a set of “global” objects so that we can have a configuration file for them, so that it can be used by all packages. If a package as some specific configuration needs, we create a specific – or “local” – XML configuration file or we set the value that needs to be configured at runtime using DTLoggedExec’s Package Parameters: http://dtloggedexec.davidemauri.it/Package%20Parameters.ashx Now, how we can improve this even more? I’d like to have a package that, when it’s run, automatically goes “somewhere” and search for global or local configuration, loads it and applies it to itself. That’s the basic idea of Auto-Configuring Packages. The “somewhere” is a SQL Server table, defined in this way In this table you’ll put the values that you want to be used at runtime by your package: The ConfigurationFilter column specify to which package that configuration line has to be applied. A package will use that line only if the value specified in the ConfigurationFilter column is equal to its name. In the above sample. only the package named “simple-package” will use the line number two. There is an exception here: the $$Global value indicate a configuration row that has to be applied to any package. With this simple behavior it’s possible to replicate the “global” and the “local” configuration approach I’ve described before. The ConfigurationValue contains the value you want to be applied at runtime and the PackagePath contains the object to which that value will be applied. The ConfiguredValueType column defined the data type of the value and the Checksum column is contains a calculated value that is simply the hash value of ConfigurationFilter plus PackagePath so that it can be used as a Primary Key to guarantee uniqueness of configuration rows. As you may have noticed the table is very similar to the table originally used by SSIS in order to put DTS Configuration into SQL Server tables: SQL Server SSIS Configuration Type: http://msdn.microsoft.com/en-us/library/ms141682.aspx Now, how it works? It’s very easy: you just have to call DTLoggedExec with the /AC option: DTLoggedExec.exe /FILE:”mypackage.dtsx” /AC:"localhost;ssis_auto_configuration;ssiscfg.configuration" the AC option expects a string with the following format: <database_server>;<database_name>;<table_name>; only Windows Authentication is supported. When DTLoggedExec finds an Auto-Configuration request, it injects a new connection manager in the loaded package. The injected connection manager is named $$DTLoggedExec_AutoConfigure and is used by the two SQL Server DTS Configuration ($$DTLoggedExec_Global and $$DTLoggedExec_Local) also injected by DTLoggedExec, used to load “local” and “global” configuration. Now, you may start to wonder why this approach cannot be used without having all this stuff going around, but just passing to a package always two XML DTS Configuration files, (to have to “local” and the “global” configurations) doing something like this: DTLoggedExec.exe /FILE:”mypackage.dtsx” /CONF:”global.dtsConfig” /CONF:”mypackage.dtsConfig” The problem is that this approach doesn’t work if you have, in one of the two configuration file, a value that has to be applied to an object that doesn’t exists in the loaded package. This situation will raise an error that will halt package execution. To solve this problem, you may want to create a configuration file for each package. Unfortunately this will make deployment and management harder, since you’ll have to deal with a great number of configuration files. The Auto-Configuration approach solve all these problems at once! We’re using it in a project where we have hundreds of packages and I can tell you that deployment of packages and their configuration for the pre-production and production environment has never been so easy! To use the Auto-Configuration option you have to download the latest DTLoggedExec release: http://dtloggedexec.codeplex.com/releases/view/62218 Feedback, as usual, are very welcome!

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  • C Problem with Compiler?

    - by Solomon081
    I just started learning C, and wrote my hello world program: #include <stdio.h> main() { printf("Hello World"); return 0; } When I run the code, I get a really long error: Apple Mach-O Linker (id) Error Ld /Users/Solomon/Library/Developer/Xcode/DerivedData/CProj-cwosspupvengheeaapmkrhxbxjvk/Build/Products/Debug/CProj normal x86_64 cd /Users/Solomon/Desktop/C/CProj setenv MACOSX_DEPLOYMENT_TARGET 10.7 /Developer/usr/bin/clang -arch x86_64 -isysroot /Developer/SDKs/MacOSX10.7.sdk -L/Users/Solomon/Library/Developer/Xcode/DerivedData/CProj-cwosspupvengheeaapmkrhxbxjvk/Build/Products/Debug -F/Users/Solomon/Library/Developer/Xcode/DerivedData/CProj-cwosspupvengheeaapmkrhxbxjvk/Build/Products/Debug -filelist /Users/Solomon/Library/Developer/Xcode/DerivedData/CProj-cwosspupvengheeaapmkrhxbxjvk/Build/Intermediates/CProj.build/Debug/CProj.build/Objects-normal/x86_64/CProj.LinkFileList -mmacosx-version-min=10.7 -o /Users/Solomon/Library/Developer/Xcode/DerivedData/CProj-cwosspupvengheeaapmkrhxbxjvk/Build/Products/Debug/CProj ld: duplicate symbol _main in /Users/Solomon/Library/Developer/Xcode/DerivedData/CProj-cwosspupvengheeaapmkrhxbxjvk/Build/Intermediates/CProj.build/Debug/CProj.build/Objects-normal/x86_64/helloworld.o and /Users/Solomon/Library/Developer/Xcode/DerivedData/CProj-cwosspupvengheeaapmkrhxbxjvk/Build/Intermediates/CProj.build/Debug/CProj.build/Objects-normal/x86_64/main.o for architecture x86_64 Command /Developer/usr/bin/clang failed with exit code 1 I am running xCode Should I reinstall DevTools?

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  • Read only array, deep copy or retrieve copies one by one? (Performance and Memory)

    - by Arthur Wulf White
    In a garbage collection based system, what is the most effective way to handle a read only array if such a structure does not exist natively in the language. Is it better to return a copy of an array or allow other classes to retrieve copies of the objects stored in the array one by one? @JustinSkiles: It is not very broad. It is performance related and can actually be answered specifically for two general cases. You only need very few items: in this situation it's more effective to retrieve copies of the objects one by one. You wish to iterate over 30% or more objects. In this cases it is superior to retrieve all the array at once. This saves on functions calls. Function calls are very expansive when compared to reading directly from an array. A good specific answer could include performance, reading from an array and reading indirectly through a function. It is a simple performance related question.

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  • How can I create and animate 2D skeletons for HTML5 Javascript games? [on hold]

    - by user414209
    I'm trying to make a 2D fighting game in HTML5(somewhat like street fighter). So basically there are two players, one AI and one Human. The players need to have animations for the body movements. Also, there needs to be some collision detection system. I'm using createjs for coding but to design models/objects/animations, I need some other software. So I'm looking for a software that can: easily make custom animation of 2d objects. The objects structure(skeleton etc.) will be same once defined but need to be defined once. Can export the animations and models in a js readable format(preferably json) Collision detection can be done easily after the exported format is loaded in a game engine. For point 1, I'm looking for some generic skeleton based animation. Sprite-sheet based animations will be difficult for collision detection.

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  • Solving 2D Collision Detection Issues with Relative Velocities

    - by Jengerer
    Imagine you have a situation where two objects are moving parallel to one-another and are both within range to collide with a static wall, like this: A common method used in dynamic collision detection is to loop through all objects in arbitrary order, solve for pair-wise collision detection using relative velocities, and then move the object to the nearest collision, if any. However, in this case, if the red object is checked first against the blue one, it would see that the relative velocity to the blue object is -20 m/s (and would thereby not collide this time frame). Then it would see that the red object would collide with the static wall, and the solution would be: And the red object passes through the blue one. So it appears to be a matter of choosing the right order in which you check collisions; but how can you determine which order is correct? How can this passing through of objects be avoided? Is ignoring relative velocity and considering every object as static during pair-wise checks a better idea for this reason?

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  • Is there really Object-relational impedance mismatch?

    - by user52763
    It is always stated that it is hard to store applications objects in relational databases - the object-relational impedance mismatch - and that is why Document databases are better. However, is there really an impedance mismatch? And object has a key (albeit it may be hidden away by the runtime as a pointer to memory), a set of values, and foreign keys to other objects. Objects are as much made up of tables as it is a document. Neither really fit. I can see a use for databases to model the data into specific shapes for scenarios in the application - e.g. to speed up database lookup and avoid joins, etc., but won't it be better to keep the data as normalized as possible at the core, and transform as required?

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  • XNA Transparency depending on drawing order?

    - by DarthRoman
    I am drawing two 3D objects, both of them can fade from opaque to transparent independently, and they can intersect between them (so you cannot say when one of them is before the other one). Look at the image for a better understanding (one of the object is a terrain and the other one an area): Now, if I apply transparency to both of them, and draw the terrain before the area, the terrain is not transparent respecting to the area, but the area is: And finally, if I draw the area before the terrain, then the area is not transparent respecting of the terrain: QUESTION: How can I make all the objects transparent to the rest of objects without depending on the drawing order?

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  • Motivation and use of move constructors in C++

    - by Giorgio
    I recently have been reading about move constructors in C++ (see e.g. here) and I am trying to understand how they work and when I should use them. As far as I understand, a move constructor is used to alleviate the performance problems caused by copying large objects. The wikipedia page says: "A chronic performance problem with C++03 is the costly and unnecessary deep copies that can happen implicitly when objects are passed by value." I normally address such situations by passing the objects by reference, or by using smart pointers (e.g. boost::shared_ptr) to pass around the object (the smart pointers get copied instead of the object). What are the situations in which the above two techniques are not sufficient and using a move constructor is more convenient?

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  • What is a correct step by step logic of exporting scene with baked occlusion for loading it at runtime?

    - by myWallJSON
    I wonder what is a correct step by step logic of exporting scene with baked occlusion (Culling data) for loading that scene at runtime (on fly from the internet for example))? So currently my plan looks like this: I create prefabs Place them onto my scene (into Hierarchy) (say create 20 buffolows and some hourses and some buildings) Create empty prefab and drag all my scene objects from hierarchy onto it Export prefab So generally I put all my scene objects into one large prefab and export it but it seems that all objects that were marked as static get this property turned off when loading them at runtime and so no Frustrum Culling, and no Occlusion culling happens. So I wonder what is a correct way of exporting Sceen + Objecrts + Occlusion (and onther culing) data for future load of such scene at runtime? I wonder about current 3.5.2 Pro and future 4 Pro versions of U3D.

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  • 2D vector graphic html5 framework

    - by Yury
    I trying to find html5 game framework by following criteria: 1)Real good performance. 2)Good support of vector graphic( objects which contains canvas elements -line, rec,bezierCurve etc.) 3)Easy port to mobile. Optional- Physics Engine. I found 1)Pixi.js- it looks like real good, but i didn't find any info about "vector objects" support. 2) i found "vector objects" support in paper.js I need something like these: http://paperjs.org/examples/chain/ and http://paperjs.org/examples/path-intersections/. But it looks like paper.js- not so good performance as pixi.js. And it is not game engine. Is there any good framework meets these requirements? P.S. I found similar question here Which free HTML5-based game engine meets these requirements?. But it was a long time ago. A lot of new things were created since 2011.

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  • ADF Business Components

    - by Arda Eralp
    ADF Business Components and JDeveloper simplify the development, delivery, and customization of business applications for the Java EE platform. With ADF Business Components, developers aren't required to write the application infrastructure code required by the typical Java EE application to: Connect to the database Retrieve data Lock database records Manage transactions   ADF Business Components addresses these tasks through its library of reusable software components and through the supporting design time facilities in JDeveloper. Most importantly, developers save time using ADF Business Components since the JDeveloper design time makes typical development tasks entirely declarative. In particular, JDeveloper supports declarative development with ADF Business Components to: Author and test business logic in components which automatically integrate with databases Reuse business logic through multiple SQL-based views of data, supporting different application tasks Access and update the views from browser, desktop, mobile, and web service clients Customize application functionality in layers without requiring modification of the delivered application The goal of ADF Business Components is to make the business services developer more productive.   ADF Business Components provides a foundation of Java classes that allow your business-tier application components to leverage the functionality provided in the following areas: Simplifying Data Access Design a data model for client displays, including only necessary data Include master-detail hierarchies of any complexity as part of the data model Implement end-user Query-by-Example data filtering without code Automatically coordinate data model changes with business services layer Automatically validate and save any changes to the database   Enforcing Business Domain Validation and Business Logic Declaratively enforce required fields, primary key uniqueness, data precision-scale, and foreign key references Easily capture and enforce both simple and complex business rules, programmatically or declaratively, with multilevel validation support Navigate relationships between business domain objects and enforce constraints related to compound components   Supporting Sophisticated UIs with Multipage Units of Work Automatically reflect changes made by business service application logic in the user interface Retrieve reference information from related tables, and automatically maintain the information when the user changes foreign-key values Simplify multistep web-based business transactions with automatic web-tier state management Handle images, video, sound, and documents without having to use code Synchronize pending data changes across multiple views of data Consistently apply prompts, tooltips, format masks, and error messages in any application Define custom metadata for any business components to support metadata-driven user interface or application functionality Add dynamic attributes at runtime to simplify per-row state management   Implementing High-Performance Service-Oriented Architecture Support highly functional web service interfaces for business integration without writing code Enforce best-practice interface-based programming style Simplify application security with automatic JAAS integration and audit maintenance "Write once, run anywhere": use the same business service as plain Java class, EJB session bean, or web service   Streamlining Application Customization Extend component functionality after delivery without modifying source code Globally substitute delivered components with extended ones without modifying the application   ADF Business Components implements the business service through the following set of cooperating components: Entity object An entity object represents a row in a database table and simplifies modifying its data by handling all data manipulation language (DML) operations for you. These are basically your 1 to 1 representation of a database table. Each table in the database will have 1 and only 1 EO. The EO contains the mapping between columns and attributes. EO's also contain the business logic and validation. These are you core data services. They are responsible for updating, inserting and deleting records. The Attributes tab displays the actual mapping between attributes and columns, the mapping has following fields: Name : contains the name of the attribute we expose in our data model. Type : defines the data type of the attribute in our application. Column : specifies the column to which we want to map the attribute with Column Type : contains the type of the column in the database   View object A view object represents a SQL query. You use the full power of the familiar SQL language to join, filter, sort, and aggregate data into exactly the shape required by the end-user task. The attributes in the View Objects are actually coming from the Entity Object. In the end the VO will generate a query but you basically build a VO by selecting which EO need to participate in the VO and which attributes of those EO you want to use. That's why you have the Entity Usage column so you can see the relation between VO and EO. In the query tab you can clearly see the query that will be generated for the VO. At this stage we don't need it and just use it for information purpose. In later stages we might use it. Application module An application module is the controller of your data layer. It is responsible for keeping hold of the transaction. It exposes the data model to the view layer. You expose the VO's through the Application Module. This is the abstraction of your data layer which you want to show to the outside word.It defines an updatable data model and top-level procedures and functions (called service methods) related to a logical unit of work related to an end-user task. While the base components handle all the common cases through built-in behavior, customization is always possible and the default behavior provided by the base components can be easily overridden or augmented. When you create EO's, a foreign key will be translated into an association in our model. It defines the type of relation and who is the master and child as well as how the visibility of the association looks like. A similar concept exists to identify relations between view objects. These are called view links. These are almost identical as association except that a view link is based upon attributes defined in the view object. It can also be based upon an association. Here's a short summary: Entity Objects: representations of tables Association: Relations between EO's. Representations of foreign keys View Objects: Logical model View Links: Relationships between view objects Application Model: interface to your application  

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  • QuadTree: store only points, or regions?

    - by alekop
    I am developing a quadtree to keep track of moving objects for collision detection. Each object has a bounding shape, let's say they are all circles. (It's a 2D top-down game) I am unsure whether to store only the position of each object, or the whole bounding shape. If working with points, insertion and subdivision is easy, because objects will never span multiple nodes. On the other hand, a proximity query for an object may miss collisions, because it won't take the objects' dimensions into account. How to calculate the query region when you only have points? If working with regions, how to handle an object that spans multiple nodes? Should it be inserted in the nearest parent node that completely contains it, even if this exceeds the node's capacity? Thanks.

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  • Passing data between engine layers

    - by spaceOwl
    I am building a software system (game engine with networking support ) that is made up of (roughly) these layers: Game Layer Messaging Layer Networking Layer Game related data is passed to the messaging layer (this could be anything that is game specific), where they are to be converted to network specific messages (which are then serialized to byte arrays). I'm looking for a way to be able to convert "game" data into "network" data, such that no strong coupling between these layers will exist. As it looks now, the Messaging layer sits between both layers (game and network) and "knows" both of them (it contains Converter objects that know how to translate between data objects of both layers back and forth). I am not sure this is the best solution. Is there a good design for passing objects between layers? I'd like to learn more about the different options.

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  • Find Nearest Object

    - by ultifinitus
    I have a fairly sizable game engine created, and I'm adding some needed features, such as this, how do I find the nearest object from a list of points? In this case, I could simply use the Pythagorean theorem to find the distance, and check the results. I know I can't simply add x and y, because that's the distance to the object, if you only took right angle turns. However I'm wondering if there's something else I could do? I also have a collision system, where essentially I turn objects into smaller objects on a smaller grid, kind of like a minimap, and only if objects exist in the same gridspace do I check for collisions, I could do the same thing, only make the gridspace larger to check for closeness. (rather than checking every. single. object) however that would take additional setup in my base class and clutter up the already cluttered object. TL;DR Question: Is there something efficient and accurate that I can use to detect which object is closest, based on a list of points and sizes?

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  • Optimizing hierarchical transform

    - by Geotarget
    I'm transforming objects in 3D space by transforming each vector with the object's 4x4 transform matrix. In order to achieve hierarchical transform, I transform the child by its own matrix, and then the child by the parent matrix. This becomes costly because objects deeper in the display tree have to be transformed by all the parent objects. This is what's happening, in summary: Root -- transform its verts by Root matrix Parent -- transform its verts by Parent, Root matrix Child -- transform its verts by Child, Parent, Root matrix Is there a faster way to transform vertices to achieve hierarchical transform? What If I first concatenated each transform matrix with the parent matrices, and then transform verts by that final resulting matrix, would that work and wouldn't that be faster? Root -- transform its verts by Root matrix Parent -- concat Parent, Root matrices, transform its verts by Concated matrix Child -- concat Child, Parent, Root matrices, transform its verts by Concated matrix

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  • Coherence Data Guarantees for Data Reads - Basic Terminology

    - by jpurdy
    When integrating Coherence into applications, each application has its own set of requirements with respect to data integrity guarantees. Developers often describe these requirements using expressions like "avoiding dirty reads" or "making sure that updates are transactional", but we often find that even in a small group of people, there may be a wide range of opinions as to what these terms mean. This may simply be due to a lack of familiarity, but given that Coherence sits at an intersection of several (mostly) unrelated fields, it may be a matter of conflicting vocabularies (e.g. "consistency" is similar but different in transaction processing versus multi-threaded programming). Since almost all data read consistency issues are related to the concept of concurrency, it is helpful to start with a definition of that, or rather what it means for two operations to be concurrent. Rather than implying that they occur "at the same time", concurrency is a slightly weaker statement -- it simply means that it can't be proven that one event precedes (or follows) the other. As an example, in a Coherence application, if two client members mutate two different cache entries sitting on two different cache servers at roughly the same time, it is likely that one update will precede the other by a significant amount of time (say 0.1ms). However, since there is no guarantee that all four members have their clocks perfectly synchronized, and there is no way to precisely measure the time it takes to send a given message between any two members (that have differing clocks), we consider these to be concurrent operations since we can not (easily) prove otherwise. So this leads to a question that we hear quite frequently: "Are the contents of the near cache always synchronized with the underlying distributed cache?". It's easy to see that if an update on a cache server results in a message being sent to each near cache, and then that near cache being updated that there is a window where the contents are different. However, this is irrelevant, since even if the application reads directly from the distributed cache, another thread update the cache before the read is returned to the application. Even if no other member modifies a cache entry prior to the local near cache entry being updated (and subsequently read), the purpose of reading a cache entry is to do something with the result, usually either displaying for consumption by a human, or by updating the entry based on the current state of the entry. In the former case, it's clear that if the data is updated faster than a human can perceive, then there is no problem (and in many cases this can be relaxed even further). For the latter case, the application must assume that the value might potentially be updated before it has a chance to update it. This almost aways the case with read-only caches, and the solution is the traditional optimistic transaction pattern, which requires the application to explicitly state what assumptions it made about the old value of the cache entry. If the application doesn't want to bother stating those assumptions, it is free to lock the cache entry prior to reading it, ensuring that no other threads will mutate the entry, a pessimistic approach. The optimistic approach relies on what is sometimes called a "fuzzy read". In other words, the application assumes that the read should be correct, but it also acknowledges that it might not be. (I use the qualifier "sometimes" because in some writings, "fuzzy read" indicates the situation where the application actually sees an original value and then later sees an updated value within the same transaction -- however, both definitions are roughly equivalent from an application design perspective). If the read is not correct it is called a "stale read". Going back to the definition of concurrency, it may seem difficult to precisely define a stale read, but the practical way of detecting a stale read is that is will cause the encompassing transaction to roll back if it tries to update that value. The pessimistic approach relies on a "coherent read", a guarantee that the value returned is not only the same as the primary copy of that value, but also that it will remain that way. In most cases this can be used interchangeably with "repeatable read" (though that term has additional implications when used in the context of a database system). In none of cases above is it possible for the application to perform a "dirty read". A dirty read occurs when the application reads a piece of data that was never committed. In practice the only way this can occur is with multi-phase updates such as transactions, where a value may be temporarily update but then withdrawn when a transaction is rolled back. If another thread sees that value prior to the rollback, it is a dirty read. If an application uses optimistic transactions, dirty reads will merely result in a lack of forward progress (this is actually one of the main risks of dirty reads -- they can be chained and potentially cause cascading rollbacks). The concepts of dirty reads, fuzzy reads, stale reads and coherent reads are able to describe the vast majority of requirements that we see in the field. However, the important thing is to define the terms used to define requirements. A quick web search for each of the terms in this article will show multiple meanings, so I've selected what are generally the most common variations, but it never hurts to state each definition explicitly if they are critical to the success of a project (many applications have sufficiently loose requirements that precise terminology can be avoided).

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  • World to Pixel Transformation

    - by D00d
    My objects have a location in world coordinates (basically 1.0f is a meter). If I simply draw my objects using their world coordinates, each meter will correspond to a pixel. Obviously that's not what I want. Now, I don't want to have to apply a transformation to each and every object's position when I draw them. As I happen to be using XNA, and spritebatch allows a Matrix to be passed in as an argument in it's begin method, I was wondering if there is a way to pass the World to Pixel transformation in there. Any suggestions? So far Matrix.CreateScale(new Vector3(zoom, zoom, 1)) puts the objects in their proper spot, but it also scales up the sprites. Is there a way to transform the position without enlarging the sprite? Thanks

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  • What would be a good game making engine supporting Vector images?

    - by Qqwy
    I want to create a simple platforming game, in which you are a square in a wonderful world. I would like this game to be able to be played in browsers. Basically I am searching for something similar to "Flixel", but with the following features: Support Vector Graphics Allow zooming/rotating objects without producing huge amounts of lag as soon as you are using more objects. (Because I want to rotate the map around the player) So in other words, preferably zoom the viewport/camera instead of the objects themselves. Does an engine like that exist?

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  • EBS Applications Technology Group (ATG) Advisor Webcast December 2012

    - by LuciaC
    Invitation : Advisor Webcast December 2012 In December 2012 we have scheduled an Advisor Webcast, where we want to give you a closer look into the invalid objects in an E-Business Suite Environment. E-Business Suite - Troubleshooting invalid objectsAgenda : Introduction Activities that generate invalid objects EBS Architecture EBS Patching Concepts Troubleshooting Invalid Objects References EMEA Session : Tuesday December 11th, 2012 at 09:00 AM UK / 10:00 AM CET / 13:30 India / 17:00 Japan / 18:00 Australia Details & Registration : Doc ID 1501696.1Direct link to register in WebExUS Session : Wednesday December 12th, 2012 at 18:00 UK / 19:00 CET / 10:00 AM Pacific / 11:00 AM Mountain/ 01:00 PM Eastern Details & Registration : Doc ID 1501697.1Direct link to register in WebExIf you have any question about the schedules or if you have a suggestion for an Advisor Webcast to be planned in future, please send an E-Mail to Ruediger Ziegler.

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  • Generic Handler vs Direct Reference

    - by JNF
    In a project where I'm working on the data access layer I'm trying to make a decision how to send data and objects to the next layer (and programmer). Is it better to tell him to reference my dll, OR should I build a generic handler and let him take the objects from there (i.e. json format) If I understand correctly, In case of 2. he would have to handle the objects on his own, whereas in case 1. he will have the entities I've built. Note: It is very probable that other people would need to take the same data, though, we're not up to that yet. Same question here - should I make it into a webservice, or have them access the handler?

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  • Should Business Interfaces be part of the Model layer?

    - by Mik378
    In an oriented-services enterprise application, isn't it an antipattern to mix Service APIs (containing interface that external users depends on) with Model objects (entities, custom exceptions objects etc...) ? According to me, Services should only depends on Model layer but never mixed with it. In fact, my colleague told me that it doesn't make sense to separate it since client need both. (model and service interfaces) But I notice that everytime a client asks for some changes, like adding a new method in some interface (means a new service), Model layer has to be also delivered... Thus, client who has not interested by this "addition" is constrained to be concerned by this update of Model... and in a large enterprise application, this kind of delivery is known to be very risked... What is the best practice ? Separate services(only interfaces so) and model objects or mix it ?

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  • F# - When do you use a class instead of a record when you do not want to use mutable fields?

    - by fairflow
    I'm imagining a situation where you are creating an F# module in a purely functional style. This means objects do not have mutable fields and are not modified in place. I'm assuming for simplicity that there is no need to use .NET objects or other kinds of objects. There are two possible ways of implementing an object-oriented kind of solution: the first is to use type classes and the second to use records which have fields of functional type, to implement methods. I imagine you'd use classes when you want to use inheritance but that otherwise records would be adequate, if perhaps clumsier to express. Or do you find classes more convenient than records in any case?

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