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  • Finding the normals of an oriented bounding box?

    - by Milo
    Here is my problem. I'm working on the physics for my 2D game. All objects are oriented bounding boxes (OBB) based on the separate axis theorem. In order to do collision resolution, I need to be able to get an object out out of the object it is penetrating. To do this I need to find the normal of the face(s) that the other OBB is touching. Example: The small red OBB is a car lets say, and the big OBB is a static building. I need to determine the unit vector that is the normal of the building edge(s) the car is penetrating to get the car out of there. Here are my questions: How do I determine which edges the car is penetrating. I know how to determine the normal of an edge, but how do I know if I need (-dy, dx) or (dy, -dx)? In the case I'm demonstrating the car is penetrating 2 edges, which edge(s) do I use to get it out? Answers or help with any or all of these is greatly appreciated. Thank you

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  • Phishing attack stuck with jsp loginAction.do page?

    - by user970533
    I'm testing a phishing website on a staged replica of an jsp web-application. I'm doing the usual attack which involves changing the post and action field of source code to divert to my own written jsp script capture the logins and redirect the victim to the original website. It looks easy, but trust me, it's has been me more then 2 weeks and I cannot write the logins to the text file. I have tested the jsp page on my local wamp server it works fine. In staged, when I click on the ok button for user/password field I'm taken to loginAction.do script. I checked this using the tamper data add-on on Firefox. The only way I was able to make my script run was to use burp proxy intercept the request and change action parameter to refer my uploaded script. I want to know what does an loginAction.do? I have googled it - it's quite common to see it in jsp application. I have checked the code; there is nothing that tells me why the page always points to the .do script instead of mine. Is there some kind of redirection in Tomcat? I like to know. I'm unable to exploit this attack vector? I need the community's help.

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  • Java Spotlight Episode 87: Nandini Ramani on Java FX and Embedded Java

    - by Roger Brinkley
    Interview with Nandini Ramani on JavaFX and Embedded Java. Joining us this week on the Java All Star Developer Panel is Arun Gupta, Java EE Guy. Right-click or Control-click to download this MP3 file. You can also subscribe to the Java Spotlight Podcast Feed to get the latest podcast automatically. If you use iTunes you can open iTunes and subscribe with this link:  Java Spotlight Podcast in iTunes. Show Notes News JFXtras Project: There’s an app for that! JavaOne 2012 content catalog is online Native packaging for JavaFX in 2.2 EL 3.0 Public Review (JSR 341) el-spec.java.net Events June 18-20, QCon, New York City June 19, CJUG, Chicago June 20, 1871, Chicago June 26-28, Jazoon, Zurich, Switzerland Jun 27, Houston JUG July 5, Java Forum, Stuttgart, Germany Jul 13-14, IndicThreads, Delhi July 30-August 1, JVM Language Summit, Santa Clara Feature InterviewNandini Ramani is Vice President of Development at Oracle in the Fusion Middleware Group. She is responsible for the Java Client Platform and has a long history of creating innovation and futures at Sun Microsystems.Nandini launched the JavaFX Platform and tools and had been actively involved in JavaFX since its inception in May 2007. Prior to joining the client group, Nandini was in the Software CTO Office driving the emerging technologies group for incubation projects. She has a background in both hardware and software, having worked in hardware architecture and simulation team in the Accelerated Graphics group and the graphics and media team in the JavaME group. She was involved in the development of XML standards, as Co-Chair of the W3C Scalable Vector Graphics working group and as a member of the W3C Compound Document Formats working group. She was also a member of several graphics and UI related expert groups in the JCP. Mail Bag What’s Cool "OpenJDK is now the heart of a vital piece of technology that runs large parts of our entire civilization.” Java Magazine PetStore using Java EE 6 - Antonio Goncalves

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  • Is there ever a reason to use C++ in a Mac-only application?

    - by Emil Eriksson
    Is there ever a reason to use C++ in a Mac-only application? I not talking about integrating external libraries which are C++, what I mean is using C++ because of any advantages in a particular application. While the UI code must be written in Obj-C, what about logic code? Because of the dynamic nature of Objective-C, C++ method calls tend to be ever so slightly faster but does this have any effect in any imaginable real life scenario? For example, would it make sense to use C++ over Objective-C for simulating large particle systems where some methods would need to be called over and over in short time? I can also see some cases where C++ has a more appropriate "feel". For example when doing graphics, it's nice to have vector and matrix types with appropriate operator overloads and methods. This, to me, seems like it would be a bit clunkier to implement in Objective-C. Also, Objective-C objects can never be treated plain old data structures in the same manner as C++ types since Objective-C objects always have an isa-pointer. Wouldn't it make sense to use C++ instead in something like this? Does anyone have a real life example of a situation where C++ was chosen for some parts of an application? Does Apple use any C++ except for the kernel? (I don't want to start a flame war here, both languages have their merits and I use both equally though in different applications.)

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  • CodePlex Daily Summary for Tuesday, August 28, 2012

    CodePlex Daily Summary for Tuesday, August 28, 2012Popular ReleasesImageServer: v1.1: This is the first version releasedChristoc's DotNetNuke Module Development Template: DotNetNuke Project Templates V1.1 for VS2012: This release is specifically for Visual Studio 2012 Support, distributed through the Visual Studio Extensions gallery at http://visualstudiogallery.msdn.microsoft.com/ Check out the blog post for all of the details about this release. http://www.dotnetnuke.com/Resources/Blogs/EntryId/3471/New-Visual-Studio-2012-Project-Templates-for-DotNetNuke.aspx If you need a project template for older versions of Visual Studio check out our previous releases.Home Access Plus+: v8.0: v8.0828.1800 RELEASE CHANGED TO BETA Any issues, please log them on http://www.edugeek.net/forums/home-access-plus/ This is full release, NO upgrade ZIP will be provided as most files require replacing. To upgrade from a previous version, delete everything but your AppData folder, extract all but the AppData folder and run your HAP+ install Documentation is supplied in the Web Zip The Quota Services require executing a script to register the service, this can be found in there install di...Math.NET Numerics: Math.NET Numerics v2.2.0: Major linear algebra rework since v2.1, now available on Codeplex as well (previous versions were only available via NuGet). Also available as NuGet packages: PM> Install-Package MathNet.Numerics PM> Install-Package MathNet.Numerics.FSharp New: instead of the special Silverlight build we now provide a portable version supporting .Net 4, Silverlight 5 and .Net Core (WinRT) 4.5: PM> Install-Package MathNet.Numerics.PortablePhalanger - The PHP Language Compiler for the .NET Framework: 3.0.0.3391 (September 2012): New features: Extended ReflectionClass libxml error handling, constants TreatWarningsAsErrors MSBuild option OnlyPrecompiledCode configuration option; allows to use only compiled code Fixes: ArgsAware exception fix accessing .NET properties bug fix ASP.NET session handler fix for OutOfProc mode Phalanger Tools for Visual Studio: Visual Studio 2010 & 2012 New debugger engine, PHP-like debugging Lot of fixes of project files, formatting, smart indent, colorization etc. Improved ...WatchersNET CKEditor™ Provider for DotNetNuke®: CKEditor Provider 1.14.06: Whats New Added CKEditor 3.6.4 oEmbed Plugin can now handle short urls changes The Template File can now parsed from an xml file instead of js (More Info...) Style Sets can now parsed from an xml file instead of js (More Info...) Fixed Showing wrong Pages in Child Portal in the Link Dialog Fixed Urls in dnnpages Plugin Fixed Issue #6969 WordCount Plugin Fixed Issue #6973 File-Browser: Fixed Deleting of Files File-Browser: Improved loading time File-Browser: Improved the loa...MabiCommerce: MabiCommerce 1.0.1: What's NewSetup now creates shortcuts Fix spelling errors Minor enhancement to the Map window.ScintillaNET: ScintillaNET 2.5.2: This release has been built from the 2.5 branch. Version 2.5.2 is functionally identical to the 2.5.1 release but also includes the XML documentation comments file generated by Visual Studio. It is not 100% comprehensive but it will give you Visual Studio IntelliSense for a large part of the API. Just make sure the ScintillaNET.xml file is in the same folder as the ScintillaNET.dll reference you're using in your projects. (The XML file does not need to be distributed with your application)....WinRT XAML Toolkit: WinRT XAML Toolkit - 1.2.0: WinRT XAML Toolkit based on the Windows 8 RTM SDK. Download the latest source from the SOURCE CODE page. For compiled version use NuGet. You can add it to your project in Visual Studio by going to View/Other Windows/Package Manager Console and entering: PM> Install-Package winrtxamltoolkit Features AsyncUI extensions Controls and control extensions Converters Debugging helpers Imaging IO helpers VisualTree helpers Samples Recent changes NOTE: Namespace changes DebugConsol...BlackJumboDog: Ver5.7.1: 2012.08.25 Ver5.7.1 (1)?????·?????LING?????????????? (2)SMTP???(????)????、?????\?????????????????????Visual Studio Team Foundation Server Branching and Merging Guide: v2 - Visual Studio 2012: Welcome to the Branching and Merging Guide Quality-Bar Details Documentation has been reviewed by Visual Studio ALM Rangers Documentation has been through an independent technical review Documentation has been reviewed by the quality and recording team All critical bugs have been resolved Known Issues / Bugs Spelling, grammar and content revisions are in progress. Hotfix will be published.Microsoft Ajax Minifier: Microsoft Ajax Minifier 4.62: Fix for issue #18525 - escaped characters in CSS identifiers get double-escaped if the character immediately after the backslash is not normally allowed in an identifier. fixed symbol problem with nuget package. 4.62 should have nuget symbols available again. Also want to highlight again the breaking change introduced in 4.61 regarding the renaming of the DLL from AjaxMin.dll to AjaxMinLibrary.dll to fix strong-name collisions between the DLL and the EXE. Please be aware of this change and...nopCommerce. Open source shopping cart (ASP.NET MVC): nopcommerce 2.65: As some of you may know we were planning to release version 2.70 much later (the end of September). But today we have to release this intermediate version (2.65). It fixes a critical issue caused by a third-party assembly when running nopCommerce on a server with .NET 4.5 installed. No major features have been introduced with this release as our development efforts were focused on further enhancements and fixing bugs. To see the full list of fixes and changes please visit the release notes p...MyRouter (Virtual WiFi Router): MyRouter 1.2.9: . Fix: Some missing changes for fixing the window subclassing crash. · Fix: fixed bug when Run MyRouter at the first Time. · Fix: Log File · Fix: improve performance speed application · fix: solve some Exception.Private cloud DMS: Essential server-client full package: Requirements: - SQL server >= 2008 (minimal Express - for Essential recommended) - .NET 4.0 (Server) - .NET 4.0 Client profile (Client) This version allow: - full file system functionality Restrictions: - Maximum 2 parallel users - No share spaces - No hosted business groups - No digital sign functionality - No ActiveDirectory connector - No Performance cache - No workflow - No messagingJavaScript Prototype Extensions: Release 1.1.0.0: Release 1.1.0.0 Add prototype extension for object. Add prototype extension for array.Glyphx: Version 1.2: This release includes the SdlDotNet.dll dependency in the setup, which you will need.TFS Project Test Migrator: TestPlanMigration v1.0.0: Release 1.0.0 This first version do not create the test cases in the target project because the goal was to restore a Test Plan + Test Suite hierarchy after a manual user deletion without restoring all the Project Collection Database. As I discovered, deleting a Test Plan will do the following : - Delete all TestSuiteEntry (the link between a Test Suite node and a Test Case) - Delete all TestSuite (the nodes in the test hierarchy), including root TestSuite - Delete the TestPlan Test c...ERPStore eCommerce FrontOffice: ERPStore.Core V4.0.0.2 MVC4 RTM: ERPStore.Core V4.0.0.2 MVC4 RTM (Code Source)ZXing.Net: ZXing.Net 0.8.0.0: sync with rev. 2393 of the java version improved API, direct support for multiple barcode decoding, wrapper for barcode generating many other improvements and fixes encoder and decoder command line clients demo client for emguCV dev documentation startedNew ProjectsA Constraint Propogation Solver in F#: An experimental implementation of the Variable Consistency "Bucket Elimination" algorithm for constraint propogationAirline Pilot Academy: Taller de Sistemas de Información - UCB ArchiveManageSys: Something about archive managementCriteria Workflow Engine: A C++ Workflow Engine: Desing and execute business process.DnnDash Service: The DnnDash project enables administrators of DotNetNuke websites to view any installed DotNetNuke Dashboard components via other devices.Dynamics NAV UniWPF Addin: This project is Addin control for Microsoft Dynamics NAV 2009, allowing developers to put WPF controls directly to NAV page.Essai Salon de Chat: petit projet de communication basé sur une structure server / client(multi)High performance C# byte array to hex string to byte array: The performance key point for each to/from conversion is the (perpetual) repetition of the same if blocks and calculations...ImageCloudLock Backup Solution: ImageCloudLock 2012 is designed to backup your important items, like photos, financial documents, PDFs, excel documents and personal items to the Cloud service.Login with Facebook in ASP.Net MVC3 & Get data from Facebook User: This project is useful for ASP.Net MVC developer. For login with Facebook in ASP.Net MVC3 & Get data from user's facebook account.Lucy2D: Projet for developing 2D Games based on WPF and XNA. The point is to minimize effort for developers and fast prototyping.Main Street: Human Resources software for small business. Using C# and SQL Server Express.ManagedZFS: A managed implementation of the ZFS filesystem. Reliability, performance, and manageability. Also, *block-pointer rewrite* !!!Metro English Persian Dictionary: This is an English - Persian (Farsi) dictionary designed and developed for Windows 8 Metro User Interface which contains over 50000 words. My Personal Site: My Personal SiteNeverball Framework: Neverball FrameworkSample code: This project is simple a common location for me to store project skeletons and snippets for help bootstrapping other projects.Smart Card Fuzzer: SCFuzz is a smart card middleware fuzz testing tool (fuzzer). Using API hooking, SCFuzz modifies data returned by the card in order to find bugs in the host.Test Activation: Start looking into it.Vector, a .net generic collection to use instead of a List - in niche cases.: The Vector can be used as a replacement for a List if a large number of elements must be stored, and element inserts and deletes are frequent.WCF duplex Message: This is test project uses WCF to implement message broadcast.WCF! WTF?: Getting to know WCFZune to Lync Now Playing: Zune to Lync Now Playing is a simple application that let you display on your Lync Personal Note, the current song playing in Zune Player.

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  • Stage3D: Camera pans the whole screen

    - by Thomas Versteeg
    I am trying to create a 2D Stage3D game where you can move the camera around the level in an RTS style. I thought about using Orthographic Matrix3D functions for this but when I try to scroll the whole "stage" also scrolls. This is the Camera code: public function Camera2D(width:int, height:int, zoom:Number = 1) { resize(width, height); _zoom = zoom; } public function resize(width:Number, height:Number):void { _width = width; _height = height; _projectionMatrix = makeMatrix(0, width, 0, height); _recalculate = true; } protected function makeMatrix(left:Number, right:Number, top:Number, bottom:Number, zNear:Number = 0, zFar:Number = 1):Matrix3D { return new Matrix3D(Vector.<Number>([ 2 / (right - left), 0, 0, 0, 0, 2 / (top - bottom), 0, 0, 0, 0, 1 / (zFar - zNear), 0, 0, 0, zNear / (zNear - zFar), 1 ])); } public function get viewMatrix():Matrix3D { if (_recalculate) { _recalculate = false; _viewMatrix.identity(); _viewMatrix.appendTranslation( -_width / 2 - _x, -_height / 2 - y, 0); _viewMatrix.appendScale(_zoom, _zoom, 1); _renderMatrix.identity(); _renderMatrix.append(_viewMatrix); _renderMatrix.append(_projectionMatrix); } return _renderMatrix; } And the camera is send directly to the GPU with: c3d.setProgramConstantsFromMatrix(Context3DProgramType.VERTEX, 0, cameraMatrix, true); And these are the shaders: ------Vertex Shader------ m44 op, va0, vc0 mov v0, va1.xy mov v0.z, va0.z ------Fragment Shader------ tex ft0, v0, fs0 <2d,linear,nomip> mov oc, ft1 Here is a example and here are two screenshots to show what I mean: How do I only let the inside of the stage3D scroll and not the whole stage?

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  • Constant game speed independent of variable FPS in OpenGL with GLUT?

    - by Nazgulled
    I've been reading Koen Witters detailed article about different game loop solutions but I'm having some problems implementing the last one with GLUT, which is the recommended one. After reading a couple of articles, tutorials and code from other people on how to achieve a constant game speed, I think that what I currently have implemented (I'll post the code below) is what Koen Witters called Game Speed dependent on Variable FPS, the second on his article. First, through my searching experience, there's a couple of people that probably have the knowledge to help out on this but don't know what GLUT is and I'm going to try and explain (feel free to correct me) the relevant functions for my problem of this OpenGL toolkit. Skip this section if you know what GLUT is and how to play with it. GLUT Toolkit: GLUT is an OpenGL toolkit and helps with common tasks in OpenGL. The glutDisplayFunc(renderScene) takes a pointer to a renderScene() function callback, which will be responsible for rendering everything. The renderScene() function will only be called once after the callback registration. The glutTimerFunc(TIMER_MILLISECONDS, processAnimationTimer, 0) takes the number of milliseconds to pass before calling the callback processAnimationTimer(). The last argument is just a value to pass to the timer callback. The processAnimationTimer() will not be called each TIMER_MILLISECONDS but just once. The glutPostRedisplay() function requests GLUT to render a new frame so we need call this every time we change something in the scene. The glutIdleFunc(renderScene) could be used to register a callback to renderScene() (this does not make glutDisplayFunc() irrelevant) but this function should be avoided because the idle callback is continuously called when events are not being received, increasing the CPU load. The glutGet(GLUT_ELAPSED_TIME) function returns the number of milliseconds since glutInit was called (or first call to glutGet(GLUT_ELAPSED_TIME)). That's the timer we have with GLUT. I know there are better alternatives for high resolution timers, but let's keep with this one for now. I think this is enough information on how GLUT renders frames so people that didn't know about it could also pitch in this question to try and help if they fell like it. Current Implementation: Now, I'm not sure I have correctly implemented the second solution proposed by Koen, Game Speed dependent on Variable FPS. The relevant code for that goes like this: #define TICKS_PER_SECOND 30 #define MOVEMENT_SPEED 2.0f const int TIMER_MILLISECONDS = 1000 / TICKS_PER_SECOND; int previousTime; int currentTime; int elapsedTime; void renderScene(void) { (...) // Setup the camera position and looking point SceneCamera.LookAt(); // Do all drawing below... (...) } void processAnimationTimer(int value) { // setups the timer to be called again glutTimerFunc(TIMER_MILLISECONDS, processAnimationTimer, 0); // Get the time when the previous frame was rendered previousTime = currentTime; // Get the current time (in milliseconds) and calculate the elapsed time currentTime = glutGet(GLUT_ELAPSED_TIME); elapsedTime = currentTime - previousTime; /* Multiply the camera direction vector by constant speed then by the elapsed time (in seconds) and then move the camera */ SceneCamera.Move(cameraDirection * MOVEMENT_SPEED * (elapsedTime / 1000.0f)); // Requests to render a new frame (this will call my renderScene() once) glutPostRedisplay(); } void main(int argc, char **argv) { glutInit(&argc, argv); (...) glutDisplayFunc(renderScene); (...) // Setup the timer to be called one first time glutTimerFunc(TIMER_MILLISECONDS, processAnimationTimer, 0); // Read the current time since glutInit was called currentTime = glutGet(GLUT_ELAPSED_TIME); glutMainLoop(); } This implementation doesn't fell right. It works in the sense that helps the game speed to be constant dependent on the FPS. So that moving from point A to point B takes the same time no matter the high/low framerate. However, I believe I'm limiting the game framerate with this approach. Each frame will only be rendered when the time callback is called, that means the framerate will be roughly around TICKS_PER_SECOND frames per second. This doesn't feel right, you shouldn't limit your powerful hardware, it's wrong. It's my understanding though, that I still need to calculate the elapsedTime. Just because I'm telling GLUT to call the timer callback every TIMER_MILLISECONDS, it doesn't mean it will always do that on time. I'm not sure how can I fix this and to be completely honest, I have no idea what is the game loop in GLUT, you know, the while( game_is_running ) loop in Koen's article. But it's my understanding that GLUT is event-driven and that game loop starts when I call glutMainLoop() (which never returns), yes? I thought I could register an idle callback with glutIdleFunc() and use that as replacement of glutTimerFunc(), only rendering when necessary (instead of all the time as usual) but when I tested this with an empty callback (like void gameLoop() {}) and it was basically doing nothing, only a black screen, the CPU spiked to 25% and remained there until I killed the game and it went back to normal. So I don't think that's the path to follow. Using glutTimerFunc() is definitely not a good approach to perform all movements/animations based on that, as I'm limiting my game to a constant FPS, not cool. Or maybe I'm using it wrong and my implementation is not right? How exactly can I have a constant game speed with variable FPS? More exactly, how do I correctly implement Koen's Constant Game Speed with Maximum FPS solution (the fourth one on his article) with GLUT? Maybe this is not possible at all with GLUT? If not, what are my alternatives? What is the best approach to this problem (constant game speed) with GLUT? I originally posted this question on Stack Overflow before being pointed out about this site. The following is a different approach I tried after creating the question in SO, so I'm posting it here too. Another Approach: I've been experimenting and here's what I was able to achieve now. Instead of calculating the elapsed time on a timed function (which limits my game's framerate) I'm now doing it in renderScene(). Whenever changes to the scene happen I call glutPostRedisplay() (ie: camera moving, some object animation, etc...) which will make a call to renderScene(). I can use the elapsed time in this function to move my camera for instance. My code has now turned into this: int previousTime; int currentTime; int elapsedTime; void renderScene(void) { (...) // Setup the camera position and looking point SceneCamera.LookAt(); // Do all drawing below... (...) } void renderScene(void) { (...) // Get the time when the previous frame was rendered previousTime = currentTime; // Get the current time (in milliseconds) and calculate the elapsed time currentTime = glutGet(GLUT_ELAPSED_TIME); elapsedTime = currentTime - previousTime; /* Multiply the camera direction vector by constant speed then by the elapsed time (in seconds) and then move the camera */ SceneCamera.Move(cameraDirection * MOVEMENT_SPEED * (elapsedTime / 1000.0f)); // Setup the camera position and looking point SceneCamera.LookAt(); // All drawing code goes inside this function drawCompleteScene(); glutSwapBuffers(); /* Redraw the frame ONLY if the user is moving the camera (similar code will be needed to redraw the frame for other events) */ if(!IsTupleEmpty(cameraDirection)) { glutPostRedisplay(); } } void main(int argc, char **argv) { glutInit(&argc, argv); (...) glutDisplayFunc(renderScene); (...) currentTime = glutGet(GLUT_ELAPSED_TIME); glutMainLoop(); } Conclusion, it's working, or so it seems. If I don't move the camera, the CPU usage is low, nothing is being rendered (for testing purposes I only have a grid extending for 4000.0f, while zFar is set to 1000.0f). When I start moving the camera the scene starts redrawing itself. If I keep pressing the move keys, the CPU usage will increase; this is normal behavior. It drops back when I stop moving. Unless I'm missing something, it seems like a good approach for now. I did find this interesting article on iDevGames and this implementation is probably affected by the problem described on that article. What's your thoughts on that? Please note that I'm just doing this for fun, I have no intentions of creating some game to distribute or something like that, not in the near future at least. If I did, I would probably go with something else besides GLUT. But since I'm using GLUT, and other than the problem described on iDevGames, do you think this latest implementation is sufficient for GLUT? The only real issue I can think of right now is that I'll need to keep calling glutPostRedisplay() every time the scene changes something and keep calling it until there's nothing new to redraw. A little complexity added to the code for a better cause, I think. What do you think?

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  • converting a mouse click to a ray

    - by Will
    I have a perspective projection. When the user clicks on the screen, I want to compute the ray between the near and far planes that projects from the mouse point, so I can do some ray intersection code with my world. I am using my own matrix and vector and ray classes and they all work as expected. However, when I try and convert the ray to world coordinates my far always ends up as 0,0,0 and so my ray goes from the mouse click to the centre of the object space, rather than through it. (The x and y coordinates of near and far are identical, they differ only in the z coordinates where they are negatives of each other) GLint vp[4]; glGetIntegerv(GL_VIEWPORT,vp); matrix_t mv, p; glGetFloatv(GL_MODELVIEW_MATRIX,mv.f); glGetFloatv(GL_PROJECTION_MATRIX,p.f); const matrix_t inv = (mv*p).inverse(); const float unit_x = (2.0f*((float)(x-vp[0])/(vp[2]-vp[0])))-1.0f, unit_y = 1.0f-(2.0f*((float)(y-vp[1])/(vp[3]-vp[1]))); const vec_t near(vec_t(unit_x,unit_y,-1)*inv); const vec_t far(vec_t(unit_x,unit_y,1)*inv); ray = ray_t(near,far-near); What have I got wrong? (How do you unproject the mouse-point?)

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  • Drawing lines in 3D space

    - by DeadMG
    When attempting to draw a line in 3D space with D3DPT_LINELIST, then Direct3D gives me an error about an invalid vertex declaration, saying that it cannot be converted to an FVF. I am using the same vertex declaration and shader/stream setup as for my D3DPT_TRIANGLELIST rendering which works absolutely correctly. How can I use D3DPT_LINELIST to render some lines in 3D space? Edit: Oopsie, forgot my codeses. Here's my raw Draw call. D3DCALL(device->SetStreamSource(1, PerBoneBuffer.get(), 0, sizeof(PerInstanceData))); D3DCALL(device->SetStreamSourceFreq(1, D3DSTREAMSOURCE_INSTANCEDATA | 1)); D3DCALL(device->SetStreamSource(0, LineVerts, 0, sizeof(D3DXVECTOR3))); D3DCALL(device->SetStreamSourceFreq(0, D3DSTREAMSOURCE_INDEXEDDATA | lines.size())); D3DCALL(device->SetIndices(LineIndices)); PerInstanceData* data; std::vector<Wide::Render::Line*> lines_vec(lines.begin(), lines.end()); D3DCALL(PerBoneBuffer->Lock(0, lines.size() * sizeof(PerInstanceData), reinterpret_cast<void**>(&data), D3DLOCK_DISCARD)); std::for_each(lines.begin(), lines.end(), [&](Wide::Render::Line* ptr) { data->Color = D3DXColor(ptr->Colour); D3DXMATRIXA16 Translate, Scale, Rotate; D3DXMatrixTranslation(&Translate, ptr->Start.x, ptr->Start.y, ptr->Start.z); D3DXMatrixScaling(&Scale, ptr->Scale, 1, 1); D3DXMatrixRotationQuaternion(&Rotate, &D3DQuaternion(ptr->Rotation)); data->World = Scale * Rotate * Translate; }); D3DCALL(PerBoneBuffer->Unlock()); D3DCALL(device->DrawIndexedPrimitive(D3DPRIMITIVETYPE::D3DPT_LINELIST, 0, 0, 2, 0, 1)); Here's my vertex declaration: D3DVERTEXELEMENT9 BasicMeshVertices[] = { {0, 0, D3DDECLTYPE_FLOAT3, D3DDECLMETHOD_DEFAULT, D3DDECLUSAGE_POSITION, 0}, {1, 0, D3DDECLTYPE_FLOAT4, D3DDECLMETHOD_DEFAULT, D3DDECLUSAGE_TEXCOORD, 0}, {1, 16, D3DDECLTYPE_FLOAT4, D3DDECLMETHOD_DEFAULT, D3DDECLUSAGE_TEXCOORD, 1}, {1, 32, D3DDECLTYPE_FLOAT4, D3DDECLMETHOD_DEFAULT, D3DDECLUSAGE_TEXCOORD, 2}, {1, 48, D3DDECLTYPE_FLOAT4, D3DDECLMETHOD_DEFAULT, D3DDECLUSAGE_TEXCOORD, 3}, {1, 64, D3DDECLTYPE_FLOAT4, D3DDECLMETHOD_DEFAULT, D3DDECLUSAGE_COLOR, 0}, D3DDECL_END() }; The LineIndices are just 0, 1 and the LineVerts are just {0,0,0} and {1,0,0}, to represent a unit 3D line along the X axis.

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  • Internet Explorer 9 Preview 2 link + webcasts for developers

    - by Eric Nelson
    At Web Directions last week in London (10th and 11th June 2010) I promised several folks I would put up a blog post to more information on IE 9.0. True to my word (albeit a little later than I had hoped), here is what I was thinking of: Install First up, Install Preview 2 and try out the demos I was showing at the conference. Remember that IE9 Preview installs side by side with IE8/7 etc. It is not a beta nor is it intended to be a full browser. It is a … preview :-)   Including good old SVG-oids :-) Learn And then check out the following webcasts which were recorded in March this year at MIX: In-Depth Look At Internet Explorer 9 Presenter:  Ted Johnson & John Hrvatin VisitMIX URL: http://live.visitmix.com/MIX10/Sessions/CL28 Slides: Download Videos: MP4 Small WMV Large WMV High Performance Best Practices For Web Sites Presenter: Jason Weber VisitMIX URL: http://live.visitmix.com/MIX10/Sessions/CL29 Slides: Download Videos: MP4 Small WMV Large WMV HTML5: Cross Browser Best Practices Presenter: Tony Ross VisitMIX URL: http://live.visitmix.com/MIX10/Sessions/CL27 Slides: Download Videos: MP4 Small WMV Large WMV Internet Explorer Developer Tools Presenter: Jon Seitel VisitMIX URL: http://live.visitmix.com/MIX10/Sessions/FT51 Slides: Download Videos: MP4 Small WMV Large WMV SVG: The Past, Present And Future of Vector Graphics For The Web Presenter: Patrick Dengler, Doug Schepers VisitMIX URL: http://live.visitmix.com/MIX10/Sessions/EX30 Slides: Download Videos: MP4 Small WMV Large WMV Day 2 Keynote containing IE9 Presenter: Dean Hachamovitch VisitMIX URL: http://live.visitmix.com/MIX10/Sessions/KEY02 Slides: Download Videos: MP4 Small WMV Large WMV

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  • LWJGL Determining whether or not a polygon is on-screen.

    - by Brandon oubiub
    Not sure whether this is an LWJGL or math question. I want to check whether a shape is on-screen, so that I don't have to render it if it isn't. First of all, is there any simple way to do this that I am overlooking? Like some method or something that I haven't found? I'm going to assume there isn't. I tried using my trigonometry skills, but it is hard to do this because of how glRotate also distorts the image a little for perspective and realism. Or, is there any way to easily determine if a ray starting from the camera, and going outward in a straight line intersects a shape? (I can probably do it with my math skillz, but is there an easier way?) By the way, I can easily determine the angle at which the camera is facing around the x and y axis. EDIT: Or, possibly, I could get the angles of a vector from the camera to the object, and compare those angles to my camera angles. But I have a feeling that the distorts from glRotate and glTranslate would be an issue. I'll try it though.

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  • jerky walljump in unity rigidbody2d

    - by Lilz Votca Love
    hey there i know people have encountered issues with it before i looked upon the different solutions provided but i couldnt get any fix at all.im making a 2d game and am stuck with the walljump.i detect the wall wonderfully i also detect the jump and it works the player jumps off the wall when facing right with the use of rigidbody.addforce(new vector2(-1,2)*jumpforce) now when jumping on the oposite wall using the same vector with the sign in x axis changed to 1,the player jumps too but it goes more in the y axis than it should.Here is an image to show you the curves it(the player) follows. check the following url to see the behaviour https://scontent-b-mad.xx.fbcdn.net/hphotos-xpf1/t1.0-9/1470386_10152415957141154_156025539179003805_n.jpg voila the green one is happennig when player faces right and the other one happens when he is not here is the section of code if (wall) { if (wallJump) { if (facingRight) { rigidbody2D.velocity = Vector2.zero; flip (); rigidbody2D.AddForce (new Vector2 (-1f, 2f) * Jumpforce / 1.5f); Debug.Log ("saut mural gauche" + new Vector2 (-1f, 2f) * Jumpforce / 1.5f); } else { rigidbody2D.velocity = Vector2.zero; flip (); rigidbody2D.AddForce (new Vector2 (1f, 2f) * Jumpforce / 1.5f); Debug.Log ("saut mural droit--" + new Vector2 (Mathf.Sign (1f), 2f) * Jumpforce / 1.5f + "jump" + jump); } } } else { wallJump = false; } here the code is not optimized yet but i assure you it works so guys any help would be so awesome!! thanks

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  • Camera Collision inside the room model

    - by sanddy
    I am having a problem in Calculating the camera collision for my Room model which consists of sofa, tables and other models. The users shall be moving the camera front, back, rotating so i need to make sure that the camera does not collide with any of the models with in the room. I have treated all my models inside the room by BoundingBox[] and the camera by BoundingSphere. So, far i have implemented collision by looking into the tutorial from http://www.toymaker.info/Games/XNA/html/xna_model_collisions.html which was great. But, I guess the problem lies in the Transformation part. I debugged and found some points to be at Vector(-XXX,-XXX,-XXX) where X is digit. Also i found my radius of some models where too large(in thousand, i just looked into its radius value before converting to BoundingBox). Do I need to scale the model for collision??? Below are my code:- On My LoadContent(): Matrix[] transforms = new Matrix[myModel.Bones.Count]; myModel.CopyAbsoluteBoneTransformsTo(transforms); int index = 0; box = new List<BoundingBox>(); BoundingBox worldModel = Utility.CalculateBoundingBox(myModel); foreach (ModelMesh mesh in myModel.Meshes) { Vector3[] obb = new Vector3[8]; worldModel.GetCorners(obb); Vector3[] asdf = (Vector3[])obb.Clone(); Vector3.Transform(obb, ref transforms[mesh.ParentBone.Index], obb); BoundingBox worldBox = BoundingBox.CreateFromPoints(obb); box.Add(worldBox); index++; } On CameraPosition Update: BoundingSphere bs = new BoundingSphere(this.cameraPos, 5.0f); if (RoomWalkthrough.Utility.CheckCollision(bs, bb)) { // Do Something } Please Help.

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  • The next next C++ [closed]

    - by Roger Pate
    It's entirely too early for speculation on what C++ will be like after C++0x, but idle hands make for wild predictions. What features would you find useful and why? Is there anything in another language that would fit nicely into the state of C++ after 0x? What should be considered for the next TC and TR? (Mostly TR, as the TC would depend more on what actually becomes the next standard.) Export was removed, rather than merely deprecated, in 0x. (It remains a keyword.) What other features carry so much baggage to also be more harmful than helpful? ISO Standards' process I'm not involved in the C++ committee, but it's also a mystery, unfortunately, to most programmers using C++. A few things worth keeping in mind: There will be 10 years between standards, barring extremely exceptional circumstances. The standard can get "bug fixes" in the form of a Technical Corrigendum. This happened to C++98 with TC1, named C++03. It fixed "simple" issues such as making the explicit guarantee that std::vector stores items contiguously, which was always intended. The committee can issue reports which can add to the language. This happened to C++98/03 with TR1 in 2005, which introduced the std::tr1 namespace.

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  • A Look Inside JSR 360 - CLDC 8

    - by Roger Brinkley
    If you didn't notice during JavaOne the Java Micro Edition took a major step forward in its consolidation with Java Standard Edition when JSR 360 was proposed to the JCP community. Over the last couple of years there has been a focus to move Java ME back in line with it's big brother Java SE. We see evidence of this in JCP itself which just recently merged the ME and SE/EE Executive Committees into a single Java Executive Committee. But just before that occurred JSR 360 was proposed and approved for development on October 29. So let's take a look at what changes are now being proposed. In a way JSR 360 is returning back to the original roots of Java ME when it was first introduced. It was indeed a subset of the JDK 4 language, but as Java progressed many of the language changes were not implemented in the Java ME. Back then the tradeoff was still a functionality, footprint trade off but the major market was feature phones. Today the market has changed and CLDC, while it will still target feature phones, will have it primary emphasis on embedded devices like wireless modules, smart meters, health care monitoring and other M2M devices. The major changes will come in three areas: language feature changes, library changes, and consolidating the Generic Connection Framework.  There have been three Java SE versions that have been implemented since JavaME was first developed so the language feature changes can be divided into changes that came in JDK 5 and those in JDK 7, which mostly consist of the project Coin changes. There were no language changes in JDK 6 but the changes from JDK 5 are: Assertions - Assertions enable you to test your assumptions about your program. For example, if you write a method that calculates the speed of a particle, you might assert that the calculated speed is less than the speed of light. In the example code below if the interval isn't between 0 and and 1,00 the an error of "Invalid value?" would be thrown. private void setInterval(int interval) { assert interval > 0 && interval <= 1000 : "Invalid value?" } Generics - Generics add stability to your code by making more of your bugs detectable at compile time. Code that uses generics has many benefits over non-generic code with: Stronger type checks at compile time. Elimination of casts. Enabling programming to implement generic algorithms. Enhanced for Loop - the enhanced for loop allows you to iterate through a collection without having to create an Iterator or without having to calculate beginning and end conditions for a counter variable. The enhanced for loop is the easiest of the new features to immediately incorporate in your code. In this tip you will see how the enhanced for loop replaces more traditional ways of sequentially accessing elements in a collection. void processList(Vector<string> list) { for (String item : list) { ... Autoboxing/Unboxing - This facility eliminates the drudgery of manual conversion between primitive types, such as int and wrapper types, such as Integer.  Hashtable<Integer, string=""> data = new Hashtable<>(); void add(int id, String value) { data.put(id, value); } Enumeration - Prior to JDK 5 enumerations were not typesafe, had no namespace, were brittle because they were compile time constants, and provided no informative print values. JDK 5 added support for enumerated types as a full-fledged class (dubbed an enum type). In addition to solving all the problems mentioned above, it allows you to add arbitrary methods and fields to an enum type, to implement arbitrary interfaces, and more. Enum types provide high-quality implementations of all the Object methods. They are Comparable and Serializable, and the serial form is designed to withstand arbitrary changes in the enum type. enum Season {WINTER, SPRING, SUMMER, FALL}; } private Season season; void setSeason(Season newSeason) { season = newSeason; } Varargs - Varargs eliminates the need for manually boxing up argument lists into an array when invoking methods that accept variable-length argument lists. The three periods after the final parameter's type indicate that the final argument may be passed as an array or as a sequence of arguments. Varargs can be used only in the final argument position. void warning(String format, String... parameters) { .. for(String p : parameters) { ...process(p);... } ... } Static Imports -The static import construct allows unqualified access to static members without inheriting from the type containing the static members. Instead, the program imports the members either individually or en masse. Once the static members have been imported, they may be used without qualification. The static import declaration is analogous to the normal import declaration. Where the normal import declaration imports classes from packages, allowing them to be used without package qualification, the static import declaration imports static members from classes, allowing them to be used without class qualification. import static data.Constants.RATIO; ... double r = Math.cos(RATIO * theta); Annotations - Annotations provide data about a program that is not part of the program itself. They have no direct effect on the operation of the code they annotate. There are a number of uses for annotations including information for the compiler, compiler-time and deployment-time processing, and run-time processing. They can be applied to a program's declarations of classes, fields, methods, and other program elements. @Deprecated public void clear(); The language changes from JDK 7 are little more familiar as they are mostly the changes from Project Coin: String in switch - Hey it only took us 18 years but the String class can be used in the expression of a switch statement. Fortunately for us it won't take that long for JavaME to adopt it. switch (arg) { case "-data": ... case "-out": ... Binary integral literals and underscores in numeric literals - Largely for readability, the integral types (byte, short, int, and long) can also be expressed using the binary number system. and any number of underscore characters (_) can appear anywhere between digits in a numerical literal. byte flags = 0b01001111; long mask = 0xfff0_ff08_4fff_0fffl; Multi-catch and more precise rethrow - A single catch block can handle more than one type of exception. In addition, the compiler performs more precise analysis of rethrown exceptions than earlier releases of Java SE. This enables you to specify more specific exception types in the throws clause of a method declaration. catch (IOException | InterruptedException ex) { logger.log(ex); throw ex; } Type Inference for Generic Instance Creation - Otherwise known as the diamond operator, the type arguments required to invoke the constructor of a generic class can be replaced with an empty set of type parameters (<>) as long as the compiler can infer the type arguments from the context.  map = new Hashtable<>(); Try-with-resource statement - The try-with-resources statement is a try statement that declares one or more resources. A resource is an object that must be closed after the program is finished with it. The try-with-resources statement ensures that each resource is closed at the end of the statement.  try (DataInputStream is = new DataInputStream(...)) { return is.readDouble(); } Simplified varargs method invocation - The Java compiler generates a warning at the declaration site of a varargs method or constructor with a non-reifiable varargs formal parameter. Java SE 7 introduced a compiler option -Xlint:varargs and the annotations @SafeVarargs and @SuppressWarnings({"unchecked", "varargs"}) to supress these warnings. On the library side there are new features that will be added to satisfy the language requirements above and some to improve the currently available set of APIs.  The library changes include: Collections update - New Collection, List, Set and Map, Iterable and Iteratator as well as implementations including Hashtable and Vector. Most of the work is too support generics String - New StringBuilder and CharSequence as well as a Stirng formatter. The javac compiler  now uses the the StringBuilder instead of String Buffer. Since StringBuilder is synchronized there is a performance increase which has necessitated the wahat String constructor works. Comparable interface - The comparable interface works with Collections, making it easier to reuse. Try with resources - Closeable and AutoCloseable Annotations - While support for Annotations is provided it will only be a compile time support. SuppressWarnings, Deprecated, Override NIO - There is a subset of NIO Buffer that have been in use on the of the graphics packages and needs to be pulled in and also support for NIO File IO subset. Platform extensibility via Service Providers (ServiceLoader) - ServiceLoader interface dos late bindings of interface to existing implementations. It helpe to package an interface and behavior of the implementation at a later point in time.Provider classes must have a zero-argument constructor so that they can be instantiated during loading. They are located and instantiated on demand and are identified via a provider-configuration file in the METAINF/services resource directory. This is a mechansim from Java SE. import com.XYZ.ServiceA; ServiceLoader<ServiceA> sl1= new ServiceLoader(ServiceA.class); Resources: META-INF/services/com.XYZ.ServiceA: ServiceAProvider1 ServiceAProvider2 ServiceAProvider3 META-INF/services/ServiceB: ServiceBProvider1 ServiceBProvider2 From JSR - I would rather use this list I think The Generic Connection Framework (GCF) was previously specified in a number of different JSRs including CLDC, MIDP, CDC 1.2, and JSR 197. JSR 360 represents a rare opportunity to consolidated and reintegrate parts that were duplicated in other specifications into a single specification, upgrade the APIs as well provide new functionality. The proposal is to specify a combined GCF specification that can be used with Java ME or Java SE and be backwards compatible with previous implementations. Because of size limitations as well as the complexity of the some features like InvokeDynamic and Unicode 6 will not be included. Additionally, any language or library changes in JDK 8 will be not be included. On the upside, with all the changes being made, backwards compatibility will still be maintained. JSR 360 is a major step forward for Java ME in terms of platform modernization, language alignment, and embedded support. If you're interested in following the progress of this JSR see the JSR's java.net project for details of the email lists, discussions groups.

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  • Bad DMA/do_IRQ errors on suspend/resume, with occasional freezing

    - by Steve Kroon
    Every time I suspend or resume my laptop (Dell Latitude E6520, bought this year), I get 2 messages of the form displayed on the console just before shutting down/starting up: [ 407.107610] ehci_hcd 0000:00:1d.0: dma_pool_free buffer-128, f6f18000/36f18000 (bad dma) On occasion, I get a message of the form: [ 3753.979066] do_IRQ: 0.177 No irq handler for vector (irq -1) On occasion, my machine freezes with a flashing Caps Lock button when suspending, after which I need to do a hard shutdown. This never happened before the messages started appearing (a while back), and I think it never happens without a do_IRQ message appearing (although I'm not sure about that). [There's nothing in the owner's manual on a flashing Caps Lock button; apparently it may be a kernel panic if the scroll lock also flashes, but the laptop doesn't have a scroll lock light, and there's no message on the console saying kernel panic.] Are these bad DMA/do IRQ messages serious, and what can I do to investigate/troubleshoot them and the freezing? Edit: I've also now received the following error messages a few times: [246943.023908] JBD: I/O error detected when updating journal superblock for sdb1. [246943.023958] Buffer I/O error on device sdb1, logical block 0 [246943.023996] EXT3-fs (sdb1): I/O error while writing superblock Edit: Output of dmesg at http://pastebin.com/ra7MTQEj ; contents of /var/log/kern.log at http://pastebin.com/i6jf0Md9 Edit: the output of some smartctl (-a, -x, --log=error, --log=xerror) instructions is available at http://paste.ubuntu.com/1088488/ . Edit (31/8/2012): Output of dmesg|grep -i ehci available at http://paste.ubuntu.com/1177246/ .

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  • Using orientation to calculate position on Windows Phone 7

    - by Lavinski
    I'm using the motion API and I'm trying to figure out a control scheme for the game I'm currently developing. What I'm trying to achive is for a orienation of the device to correlate directly to a position. Such that tilting the phone forward and to the left represents the top left position and back to the right would be the bottom right position. Photos to make it clearer (the red dot would be the calculated position). Forward and Left Back and Right Now for the tricky bit. I also have to make sure that the values take into account left landscape and right landscape device orientations (portrait is the default so no calculations would be needed for it). Has anyone done anything like this? Notes: I've tried using the yaw, pitch, roll and Quaternion readings. Sample: // Get device facing vector public static Vector3 GetState() { lock (lockable) { var down = Vector3.Forward; var direction = Vector3.Transform(down, state); switch (Orientation) { case Orientation.LandscapeLeft: return Vector3.TransformNormal(direction, Matrix.CreateRotationZ(-rightAngle)); case Orientation.LandscapeRight: return Vector3.TransformNormal(direction, Matrix.CreateRotationZ(rightAngle)); } return direction; } }

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  • Solving Big Problems with Oracle R Enterprise, Part I

    - by dbayard
    Abstract: This blog post will show how we used Oracle R Enterprise to tackle a customer’s big calculation problem across a big data set. Overview: Databases are great for managing large amounts of data in a central place with rigorous enterprise-level controls.  R is great for doing advanced computations.  Sometimes you need to do advanced computations on large amounts of data, subject to rigorous enterprise-level concerns.  This blog post shows how Oracle R Enterprise enables R plus the Oracle Database enabled us to do some pretty sophisticated calculations across 1 million accounts (each with many detailed records) in minutes. The problem: A financial services customer of mine has a need to calculate the historical internal rate of return (IRR) for its customers’ portfolios.  This information is needed for customer statements and the online web application.  In the past, they had solved this with a home-grown application that pulled trade and account data out of their data warehouse and ran the calculations.  But this home-grown application was not able to do this fast enough, plus it was a challenge for them to write and maintain the code that did the IRR calculation. IRR – a problem that R is good at solving: Internal Rate of Return is an interesting calculation in that in most real-world scenarios it is impractical to calculate exactly.  Rather, IRR is a calculation where approximation techniques need to be used.  In this blog post, we will discuss calculating the “money weighted rate of return” but in the actual customer proof of concept we used R to calculate both money weighted rate of returns and time weighted rate of returns.  You can learn more about the money weighted rate of returns here: http://www.wikinvest.com/wiki/Money-weighted_return First Steps- Calculating IRR in R We will start with calculating the IRR in standalone/desktop R.  In our second post, we will show how to take this desktop R function, deploy it to an Oracle Database, and make it work at real-world scale.  The first step we did was to get some sample data.  For a historical IRR calculation, you have a balances and cash flows.  In our case, the customer provided us with several accounts worth of sample data in Microsoft Excel.      The above figure shows part of the spreadsheet of sample data.  The data provides balances and cash flows for a sample account (BMV=beginning market value. FLOW=cash flow in/out of account. EMV=ending market value). Once we had the sample spreadsheet, the next step we did was to read the Excel data into R.  This is something that R does well.  R offers multiple ways to work with spreadsheet data.  For instance, one could save the spreadsheet as a .csv file.  In our case, the customer provided a spreadsheet file containing multiple sheets where each sheet provided data for a different sample account.  To handle this easily, we took advantage of the RODBC package which allowed us to read the Excel data sheet-by-sheet without having to create individual .csv files.  We wrote ourselves a little helper function called getsheet() around the RODBC package.  Then we loaded all of the sample accounts into a data.frame called SimpleMWRRData. Writing the IRR function At this point, it was time to write the money weighted rate of return (MWRR) function itself.  The definition of MWRR is easily found on the internet or if you are old school you can look in an investment performance text book.  In the customer proof, we based our calculations off the ones defined in the The Handbook of Investment Performance: A User’s Guide by David Spaulding since this is the reference book used by the customer.  (One of the nice things we found during the course of this proof-of-concept is that by using R to write our IRR functions we could easily incorporate the specific variations and business rules of the customer into the calculation.) The key thing with calculating IRR is the need to solve a complex equation with a numerical approximation technique.  For IRR, you need to find the value of the rate of return (r) that sets the Net Present Value of all the flows in and out of the account to zero.  With R, we solve this by defining our NPV function: where bmv is the beginning market value, cf is a vector of cash flows, t is a vector of time (relative to the beginning), emv is the ending market value, and tend is the ending time. Since solving for r is a one-dimensional optimization problem, we decided to take advantage of R’s optimize method (http://stat.ethz.ch/R-manual/R-patched/library/stats/html/optimize.html). The optimize method can be used to find a minimum or maximum; to find the value of r where our npv function is closest to zero, we wrapped our npv function inside the abs function and asked optimize to find the minimum.  Here is an example of using optimize: where low and high are scalars that indicate the range to search for an answer.   To test this out, we need to set values for bmv, cf, t, emv, tend, low, and high.  We will set low and high to some reasonable defaults. For example, this account had a negative 2.2% money weighted rate of return. Enhancing and Packaging the IRR function With numerical approximation methods like optimize, sometimes you will not be able to find an answer with your initial set of inputs.  To account for this, our approach was to first try to find an answer for r within a narrow range, then if we did not find an answer, try calling optimize() again with a broader range.  See the R help page on optimize()  for more details about the search range and its algorithm. At this point, we can now write a simplified version of our MWRR function.  (Our real-world version is  more sophisticated in that it calculates rate of returns for 5 different time periods [since inception, last quarter, year-to-date, last year, year before last year] in a single invocation.  In our actual customer proof, we also defined time-weighted rate of return calculations.  The beauty of R is that it was very easy to add these enhancements and additional calculations to our IRR package.)To simplify code deployment, we then created a new package of our IRR functions and sample data.  For this blog post, we only need to include our SimpleMWRR function and our SimpleMWRRData sample data.  We created the shell of the package by calling: To turn this package skeleton into something usable, at a minimum you need to edit the SimpleMWRR.Rd and SimpleMWRRData.Rd files in the \man subdirectory.  In those files, you need to at least provide a value for the “title” section. Once that is done, you can change directory to the IRR directory and type at the command-line: The myIRR package for this blog post (which has both SimpleMWRR source and SimpleMWRRData sample data) is downloadable from here: myIRR package Testing the myIRR package Here is an example of testing our IRR function once it was converted to an installable package: Calculating IRR for All the Accounts So far, we have shown how to calculate IRR for a single account.  The real-world issue is how do you calculate IRR for all of the accounts?This is the kind of situation where we can leverage the “Split-Apply-Combine” approach (see http://www.cscs.umich.edu/~crshalizi/weblog/815.html).  Given that our sample data can fit in memory, one easy approach is to use R’s “by” function.  (Other approaches to Split-Apply-Combine such as plyr can also be used.  See http://4dpiecharts.com/2011/12/16/a-quick-primer-on-split-apply-combine-problems/). Here is an example showing the use of “by” to calculate the money weighted rate of return for each account in our sample data set.  Recap and Next Steps At this point, you’ve seen the power of R being used to calculate IRR.  There were several good things: R could easily work with the spreadsheets of sample data we were given R’s optimize() function provided a nice way to solve for IRR- it was both fast and allowed us to avoid having to code our own iterative approximation algorithm R was a convenient language to express the customer-specific variations, business-rules, and exceptions that often occur in real-world calculations- these could be easily added to our IRR functions The Split-Apply-Combine technique can be used to perform calculations of IRR for multiple accounts at once. However, there are several challenges yet to be conquered at this point in our story: The actual data that needs to be used lives in a database, not in a spreadsheet The actual data is much, much bigger- too big to fit into the normal R memory space and too big to want to move across the network The overall process needs to run fast- much faster than a single processor The actual data needs to be kept secured- another reason to not want to move it from the database and across the network And the process of calculating the IRR needs to be integrated together with other database ETL activities, so that IRR’s can be calculated as part of the data warehouse refresh processes In our next blog post in this series, we will show you how Oracle R Enterprise solved these challenges.

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  • How can I resolve collisions at different speeds, depending on the direction?

    - by Raven Dreamer
    I have, for all intents and purposes, a Triangle class that objects in my scene can collide with (In actuality, the right side of a parallelogram). My collision detection and resolution code works fine for the purposes of preventing a gameobject from entering into the space of the Triangle, instead directing the movement along the edge. The trouble is, the maximum speed along the x and y axis is not equivalent in my game, and moving along the Y axis (up or down) should take twice as long as an equivalent distance along the X axis (left or right). Unfortunately, these speeds apply to the collision resolution too, and movement along the blue path above progresses twice as fast. What can I do in my collision resolution to make sure that the speedlimit for Y axis movement is obeyed in the latter case? Collision Resolution for this case below (vecInput and velocity are the position and velocity vectors of the game object): // y = mx+c // solve for y. M = 2, x = input's x coord, c = rightYIntercept lowY = 2*vecInput.x + parag.rightYIntercept ; ... else { // y = mx+c // vecInput.y = 2(x) + RightYIntercept // (vecInput.y - RightYIntercept) / 2 = x; //if velocity.Y (positive) greater than velocity.X (negative) //pushing from bottom, so push right. if(velocity.y > -1*velocity.x) { //change the input vector's x position to match the //y position on the shape's edge. Formula for line: Y = MX+C // M is 2, C is rightYIntercept, y is the input y, solve for X. vecInput = new Vector2((vecInput.y - parag.rightYIntercept)/2, vecInput.y); Debug.Log("adjusted rightwards"); } else { vecInput = new Vector2( vecInput.x, lowY); Debug.Log("adjusted downwards"); } }

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  • Sprites rendering blurry with velocity

    - by ashes999
    After adding velocity to my game, I feel like my textures are twitching. I thought it was just my eyes, until I finally captured it in a screenshot: The one on the left is what renders in my game; the one on the right is the original sprite, pasted over. (This is a screenshot from Photoshop, zoomed in 6x.) Notice the edges are aliasing -- it looks almost like sub-pixel rendering. In fact, if I had not forced my sprites (which have position and velocity as ints) to draw using integer values, I would swear that MonoGame is drawing with floating point values. But it isn't. What could be the cause of these things appearing blurry? It doesn't happen without velocity applied. To be precise, my SpriteComponent class has a Vector2 Position field. When I call Draw, I essentially use new Vector2((int)Math.Round(this.Position.X), (int)Math.Round(this.Position.Y)) for the position. I had a bug before where even stationary objects would jitter -- that was due to me using the straight Position vector and not rounding the values to ints. If I use Floor/Ceiling instead of round, the sprite sinks/hovers (one pixel difference either way) but still draws blurry.

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  • What is a technique for 2D ray-box intersection that is suitable for old console hardware?

    - by DJCouchyCouch
    I'm working on a Sega Genesis homebrew game (it has a 7mhz 68000 CPU). I'm looking for a way to find the intersection between a particle sprite and a background tile. Particles are represented as a point with a movement vector. Background tiles are 8 x 8 pixels, with an (X,Y) position that is always located at a multiple of 8. So, really, I need to find the intersection point for a ray-box collision; I need to find out where along the edge of the tile the ray/particle hits. I have these two hard constraints: I'm working with pixel locations (integers). Floating point is too expensive. It doesn't have to be super exact, just close enough. Multiplications, divisions, dot products, et cetera, are incredibly expensive and are to be avoided. So I'm looking for an efficient algorithm that would fit those constraints. Any ideas? I'm writing it in C, so that would work, but assembly should be good as well.

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  • How do I classify using SVM Classifier in Matlab?

    - by Gomathi
    I'm on a project of liver tumor segmentation and classification. I used Region Growing and FCM for liver and tumor segmentation respectively. Then, I used Gray Level Co-occurence matrix for texture feature extraction. I have to use Support Vector Machine for Classification. But I don't know how to normalize the feature vectors. Can anyone tell how to program it in Matlab? To the GLCM program, I gave the tumor segmented image as input. Was I correct? If so, I think, then, my output will also be correct. I gave the parameters exactly as in the example provided in the documentation itself. The output I obtained was stats = autoc: [1.857855266614132e+000 1.857955341199538e+000] contr: [5.103143332457753e-002 5.030548650257343e-002] corrm: [9.512661919561399e-001 9.519459060378332e-001] corrp: [9.512661919561385e-001 9.519459060378338e-001] cprom: [7.885631654779597e+001 7.905268525471267e+001] cshad: [1.219440700252286e+001 1.220659371449108e+001] dissi: [2.037387269065756e-002 1.935418927908687e-002] energ: [8.987753042491253e-001 8.988459843719526e-001] entro: [2.759187341212805e-001 2.743152140681436e-001] homom: [9.930016927881388e-001 9.935307908219834e-001] homop: [9.925660617240367e-001 9.930960070222014e-001] maxpr: [9.474275457490587e-001 9.474466930429607e-001] sosvh: [1.847174384255155e+000 1.846913030238459e+000] savgh: [2.332207337361002e+000 2.332108469591401e+000] svarh: [6.311174784234007e+000 6.314794324825067e+000] senth: [2.663144677055123e-001 2.653725436772341e-001] dvarh: [5.103143332457753e-002 5.030548650257344e-002] denth: [7.573115918713391e-002 7.073380266499811e-002] inf1h: [-8.199645492654247e-001 -8.265514568489666e-001] inf2h: [5.643539051044213e-001 5.661543271625117e-001] indnc: [9.980238521073823e-001 9.981394883569174e-001] idmnc: [9.993275086521848e-001 9.993404634013308e-001] The thing is, I run the program for three images. But all three gave me the same output. When I used graycoprops() stat = Contrast: 4.721877658740964e+005 Correlation: -3.282870417955449e-003 Energy: 8.647689474127760e-006 Homogeneity: 8.194621855726478e-003 stat = Contrast: 2.817160447307697e+004 Correlation: 2.113032196952781e-005 Energy: 4.124904827799189e-004 Homogeneity: 2.513567163994905e-002 stat = Contrast: 7.086638436309059e+004 Correlation: 2.459637878221028e-002 Energy: 4.640677159445994e-004 Homogeneity: 1.158305728309460e-002 The images are:

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  • Make an object slide around an obstacle

    - by Isaiah
    I have path areas set up in a game I'm making for canvas/html5 and have got it working to keep the player within these areas. I have a function isOut(boundary, x, y) that returns true if the point is outside the boundary. What I do is check only the new position x/y separately with the corresponding old position x/y. Then if each one is out I assign them the past value from the frame before. The old positions are kept in a variable from a closure I made. like this: opos = [x,y];//old position npos = [x,y];//new position if(isOut(bound, npos[0], opos[1])){ npos[0] = opos[0]; //assign it the old x position } if(isOut(bound, opos[0], npos[1])){ npos[1] = opos[1]; //assign it the old y position } It looks nice and works good at certain angles, but if your boundary has diagonal regions it results in jittery motion. What's happening is the y pos exits the area while x doesn't and continues pushing the player to the side, once it has moved the player to the side a bit the player can move forward and then the y exits again and the whole process repeats. Anyone know how I may be able to achieve a smoother slide? I have access to the player's velocity vector, the angle, and the speed(when used with the angle). I can move the play with either angle/speed or x/yvelocities as I've built in backups to translate one to the other if either have been altered manually.

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  • Collision within a poly

    - by G1i1ch
    For an html5 engine I'm making, for speed I'm using a path poly. I'm having trouble trying to find ways to get collision with the walls of the poly. To make it simple I just have a vector for the object and an array of vectors for the poly. I'm using Cartesian vectors and they're 2d. Say poly = [[550,0],[169,523],[-444,323],[-444,-323],[169,-523]], it's just a pentagon I generated. The object that will collide is object, object.pos is it's position and object.vel is it's velocity. They're both 2d vectors too. I've had some success to get it to find a collision, but it's just black box code I ripped from a c++ example. It's very obscure inside and all it does though is return true/false and doesn't return what vertices are collided or collision point, I'd really like to be able to understand this and make my own so I can have more meaningful collision. I'll tackle that later though. Again the question is just how does one find a collision to walls of a poly given you know the poly vertices and the object's position + velocity? If more info is needed please let me know. And if all anyone can do is point me to the right direction that's great.

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  • Does F# kill C++?

    - by MarkPearl
    Okay, so the title may be a little misleading… but I am currently travelling and so have had very little time and access to resources to do much fsharping – this has meant that I am right now missing my favourite new language. I was interested to see this post on Stack Overflow this evening concerning the performance of the F# language. The person posing the question asked 8 key points about the F# language, namely… How well does it do floating-point? Does it allow vector instructions How friendly is it towards optimizing compilers? How big a memory foot print does it have? Does it allow fine-grained control over memory locality? Does it have capacity for distributed memory processors, for example Cray? What features does it have that may be of interest to computational science where heavy number processing is involved? Are there actual scientific computing implementations that use it? Now, I don’t have much time to look into a decent response and to be honest I don’t know half of the answers to what he is asking, but it was interesting to see what was put up as an answer so far and would be interesting to get other peoples feedback on these questions if they know of anything other than what has been covered in the answer section already.

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