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  • XNA running slow when making a texture

    - by Anthony
    I'm using XNA to test an image analysis algorithm for a robot. I made a simple 3D world that has a grass, a robot, and white lines (that are represent the course). The image analysis algorithm is a modification of the Hough line detection algorithm. I have the game render 2 camera views to a render target in memory. One camera is a top down view of the robot going around the course, and the second camera is the view from the robot's perspective as it moves along. I take the rendertarget of the robot camera and convert it to a Color[,] so that I can do image analysis on it. private Color[,] TextureTo2DArray(Texture2D texture, Color[] colors1D, Color[,] colors2D) { texture.GetData(colors1D); for (int x = 0; x < texture.Width; x++) { for (int y = 0; y < texture.Height; y++) { colors2D[x, y] = colors1D[x + (y * texture.Width)]; } } return colors2D; } I want to overlay the results of the image analysis on the robot camera view. The first part of the image analysis is finding the white pixels. When I find the white pixels I create a bool[,] array showing which pixels were white and which were black. Then I want to convert it back into a texture so that I can overlay on the robot view. When I try to create the new texture showing which ones pixels were white, then the game goes super slow (around 10 hz). Can you give me some pointers as to what to do to make the game go faster. If I comment out this algorithm, then it goes back up to 60 hz. private Texture2D GenerateTexturesFromBoolArray(bool[,] boolArray,Color[] colorMap, Texture2D textureToModify) { for(int i =0;i < screenWidth;i++) { for(int j =0;j<screenHeight;j++) { if (boolArray[i, j] == true) { colorMap[i+(j*screenWidth)] = Color.Red; } else { colorMap[i + (j * screenWidth)] = Color.Transparent; } } } textureToModify.SetData<Color>(colorMap); return textureToModify; } Each Time I run draw, I must set the texture to null, so that I can modify it. public override void Draw(GameTime gameTime) { Vector2 topRightVector = ((SimulationMain)Game).spriteRectangleManager.topRightVector; Vector2 scaleFactor = ((SimulationMain)Game).config.scaleFactorScreenSizeToWindow; this.spriteBatch.Begin(); // Start the 2D drawing this.spriteBatch.Draw(this.textureFindWhite, topRightVector, null, Color.White, 0, Vector2.Zero, scaleFactor, SpriteEffects.None, 0); this.spriteBatch.End(); // Stop drawing. GraphicsDevice.Textures[0] = null; } Thanks for the help, Anthony G.

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  • Problem booting Windows after failed installation Ubuntu 12.04 alongside Windows 7

    - by Tassos
    I tried to install in my laptop Ubuntu 12.04 so that I can dual-boot with Windows 7. I made some mistakes during this process and I didn't manage to install Ubuntu. But my real problem now is that I'm afraid that I also destroyed the installation of Windows 7. Your help would be precious for me. Here are the details of what I did: 1) I followed these instructions to dual boot Ubuntu 12.04 and Windows 7: http://www.linuxbsdos.com/2012/05/17/how-to-dual-boot-ubuntu-12-04-and-windows-7/ The only difference from what is described above, is that in my case the device names where: /dev/mapper/isw_fdjdhbadc_Volume0* instead of: /dev/sda* Note that I had created a bootable USB stick to do that. 2) The installation proceeded normally, but in the end I got a fatal error because the grub-install failed. 3) Then, after googling this problem, I runned ubuntu from the USB stick and run this command: sudo grub-install --root-directory=/home/ubuntu/temp /dev/mapper/isw_fdjdhbadc_Volume0p5 (/isw_fdjdhbadc_Volume0p5 was the partition that I had made for /boot) but this command also failed. 4) Then, I did something stupid (I think): I run the above command as: sudo grub-install --root-directory=/home/ubuntu/temp /dev/mapper/isw_fdjdhbadc_Volume0 namely I tried to install grub in the device isw_fdjdhbadc_Volume0 instead of the boot partition isw_fdjdhbadc_Volume0p5 The above command did not fail and was executed ok. 5) After that, I tried to boot my laptop, but it seemed that I had no operation system. Not even windows were detected. 6) I thought that I should uninstall grub from isw_fdjdhbadc_Volume0. So following some online instructions that I found, I booted again Ubuntu from the USB stick and run the following command (this was stupid since the instructions were for a totally different case than mine): sudo dd if=/dev/zero of=/dev/mapper/isw_fdjdhbadc_Volume0 bs=446 count=1 Afte that, I was still unable to boot Windows. I realize that I deleted something that I shouldn't, but I'm hope that this is not crucial and I can recover somehow. When I boot Ubuntu from the USB, I can see that the partition with Windows is still there, with all the directories, Windows files, my data etc. So, my question is: Is there a way to undo the mistakes that I desribed above and recover Windows 7? This is my major question. After solving that, I'd also like to know what I did wrong with the installation of Ubuntu. Thanks in advance for you valuable help!

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  • OpenGL - have object follow mouse

    - by kevin james
    I want to have an object follow around my mouse on the screen in OpenGL. (I am also using GLEW, GLFW, and GLM). The best idea I've come up with is: Get the coordinates within the window with glfwGetCursorPos. The window was created with window = glfwCreateWindow( 1024, 768, "Test", NULL, NULL); and the code to get coordinates is double xpos, ypos; glfwGetCursorPos(window, &xpos, &ypos); Next, I use GLM unproject, to get the coordinates in "object space" glm::vec4 viewport = glm::vec4(0.0f, 0.0f, 1024.0f, 768.0f); glm::vec3 pos = glm::vec3(xpos, ypos, 0.0f); glm::vec3 un = glm::unProject(pos, View*Model, Projection, viewport); There are two potential problems I can already see. The viewport is fine, as the initial x,y, coordinates of the lower left are indeed 0,0, and it's indeed a 1024*768 window. However, the position vector I create doesn't seem right. The Z coordinate should probably not be zero. However, glfwGetCursorPos returns 2D coordinates, and I don't know how to go from there to the 3D window coordinates, especially since I am not sure what the 3rd dimension of the window coordinates even means (since computer screens are 2D). Then, I am not sure if I am using unproject correctly. Assume the View, Model, Projection matrices are all OK. If I passed in the correct position vector in Window coordinates, does the unproject call give me the coordinates in Object coordinates? I think it does, but the documentation is not clear. Finally, to each vertex of the object I want to follow the mouse around, I just increment the x coordinate by un[0], the y coordinate by -un[1], and the z coordinate by un[2]. However, since my position vector that is being unprojected is likely wrong, this is not giving good results; the object does move as my mouse moves, but it is offset quite a bit (i.e. moving the mouse a lot doesn't move the object that much, and the z coordinate is very large). I actually found that the z coordinate un[2] is always the same value no matter where my mouse is, probably because the position vector I pass into unproject always has a value of 0.0 for z. Edit: The (incorrectly) unprojected x-values range from about -0.552 to 0.552, and the y-values from about -0.411 to 0.411.

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  • Textures do not render on ATI graphics cards?

    - by Mathias Lykkegaard Lorenzen
    I'm rendering textured quads to an orthographic view in XNA through hardware instancing. On Nvidia graphics cards, this all works, tested on 3 machines. On ATI cards, it doesn't work at all, tested on 2 machines. How come? Culling perhaps? My orthographic view is set up like this: Matrix projection = Matrix.CreateOrthographicOffCenter(0, graphicsDevice.Viewport.Width, -graphicsDevice.Viewport.Height, 0, 0, 1); And my elements are rendered with the Z-coordinate 0. Edit: I just figured out something weird. If I do not call this spritebatch code above doing my textured quad rendering code, then it won't work on Nvidia cards either. Could that be due to culling information or something like that? Batch.Instance.SpriteBatch.Begin(SpriteSortMode.Immediate, BlendState.AlphaBlend, SamplerState.LinearClamp, DepthStencilState.Default, RasterizerState.CullNone); ... spriteBatch.End(); Edit 2: Here's the full code for my instancing call. public void DrawTextures() { Batch.Instance.SpriteBatch.Begin(SpriteSortMode.Texture, BlendState.AlphaBlend, SamplerState.LinearClamp, DepthStencilState.Default, RasterizerState.CullNone, textureEffect); while (texturesToDraw.Count > 0) { TextureJob texture = texturesToDraw.Dequeue(); spriteBatch.Draw(texture.Texture, texture.DestinationRectangle, texture.TintingColor); } spriteBatch.End(); #if !NOTEXTUREINSTANCING // no work to do if (positionInBufferTextured > 0) { device.BlendState = BlendState.Opaque; textureEffect.CurrentTechnique = textureEffect.Techniques["Technique1"]; textureEffect.Parameters["Texture"].SetValue(darkTexture); textureEffect.CurrentTechnique.Passes[0].Apply(); if ((textureInstanceBuffer == null) || (positionInBufferTextured > textureInstanceBuffer.VertexCount)) { if (textureInstanceBuffer != null) textureInstanceBuffer.Dispose(); textureInstanceBuffer = new DynamicVertexBuffer(device, texturedInstanceVertexDeclaration, positionInBufferTextured, BufferUsage.WriteOnly); } if (positionInBufferTextured > 0) { textureInstanceBuffer.SetData(texturedInstances, 0, positionInBufferTextured, SetDataOptions.Discard); } device.Indices = textureIndexBuffer; device.SetVertexBuffers(textureGeometryBuffer, new VertexBufferBinding(textureInstanceBuffer, 0, 1)); device.DrawInstancedPrimitives(PrimitiveType.TriangleStrip, 0, 0, textureGeometryBuffer.VertexCount, 0, 2, positionInBufferTextured); // now that we've drawn, it's ok to reset positionInBuffer back to zero, // and write over any vertices that may have been set previously. positionInBufferTextured = 0; } #endif }

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  • XNA 2D line-of-sight check

    - by bionicOnion
    I'm working on a top-down shooter in XNA, and I need to implement line-of-sight checking. I've come up with a solution that seems to work, but I get the nagging feeling that it won't be efficient enough to do every frame for multiple calls (the game already hiccups slightly at about 10 calls per frame). The code is below, but my general plan was to create a series of rectangles with a width and height of zero to act as points along the sight line, and then check to see if any of these rectangles intersects a ClutterObject (an interface I defined for things like walls or other obstacles) after first screening for any that can't possibly be in the line of sight (i.e. behind the viewer) or are too far away (a concession I made for efficiency). public static bool LOSCheck(Vector2 pos1, Vector2 pos2) { Vector2 currentPos = pos1; Vector2 perMove = (pos2 - pos1); perMove.Normalize(); HashSet<ClutterObject> clutter = new HashSet<ClutterObject>(); foreach (Room r in map.GetRooms()) { if (r != null) { foreach (ClutterObject c in r.GetClutter()) { if (c != null &&!(c.GetRectangle().X * perMove.X < 0) && !(c.GetRectangle().Y * perMove.Y < 0)) { Vector2 cVector = new Vector2(c.GetRectangle().X, c.GetRectangle().Y); if ((cVector - pos1).Length() < 1500) clutter.Add(c); } } } } while (currentPos != pos2 && ((currentPos - pos1).Length() < 1500)) { Rectangle position = new Rectangle((int)currentPos.X, (int)currentPos.Y, 0, 0); foreach (ClutterObject c in clutter) { if (position.Intersects(c.GetRectangle())) return false; } currentPos += perMove; } return true; } I'm sure that there's a better way to do this (or at least a way to make this method more efficient), but I'm not too used to XNA yet, so I figured it couldn't hurt to bring it here. At the very least, is there an efficient to determine which objects may be in front of the viewer with greater precision than the rather broad 90 degree window I've given myself?

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  • Safely deploying changes to production servers

    - by oazabir
    When you deploy incremental changes on a production server, which is running and live all the time, you some times see error messages like “Compiler Error Message: The Type ‘XXX’ exists in both…”. Sometimes you find Application_Start event not firing although you shipped a new class, dll or web.config. Sometimes you find static variables not getting initialized and so on. There are so many weird things happen on webservers when you incrementally deploy changes to the server and the server has been up and running for several weeks. So, I came up with a full proof house keeping steps that we always do whenever we deploy some incremental change to our websites. These steps ensure that the web sites are properly recycled , cached are cleared, all the data stored at Application level is initialized. First of all you should have multiple web servers behind load balancer. This way you can take one server our of the production traffic, do your deployment and house keeping tasks like restarting IIS, and then put it back. Then you can do it for the second server and so on. This ensures there’s no outage for customer. If you can do it reasonable fast, hopefully customers won’t notice discrepancy between the servers some having new code and some having old code. You should only do this when your changes aren’t drastic. For ex, you aren’t delivering a complete revamped UI. In that case, some users hitting server1 with latest UI will suddenly get a completely different experience and then on next page refresh, they might hit server2 with old code and get a totally different experience. This works for incremental non-dramatic changes only.   During deployment you should follow these steps: Take server X out of load balancer so that it does not get any traffic. Stop all windows services on the server. Stop IIS. Delete the Temporary ASP.NET folders of all .NET versions incase you have multiple .NET versions running. You can follow this link. Deploy the changes. Flush any distributed cache you have, for ex, Velocity or Memcached. Start IIS. Start the windows services on the server. Warm up all websites by hitting major URLs on the websites. You should have some automated script to do this. You can use tinyget to hit some major URLs, especially pages that take a lot of time to compile. Read my post on keeping websites warm with zero coding. Put server X back to load balancer so that it starts receiving traffic. That’s it. It should give you a clean deployment and prevent unexpected errors. You should print these steps and hang on the desk of your deployment guys so that they never forget during deployment pressure.

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  • Atmospheric scattering sky from space artifacts

    - by ollipekka
    I am in the process of implementing atmospheric scattering of a planets from space. I have been using Sean O'Neil's shaders from http://http.developer.nvidia.com/GPUGems2/gpugems2_chapter16.html as a starting point. I have pretty much the same problem related to fCameraAngle except with SkyFromSpace shader as opposed to GroundFromSpace shader as here: http://www.gamedev.net/topic/621187-sean-oneils-atmospheric-scattering/ I get strange artifacts with sky from space shader when not using fCameraAngle = 1 in the inner loop. What is the cause of these artifacts? The artifacts disappear when fCameraAngle is limtied to 1. I also seem to lack the hue that is present in O'Neil's sandbox (http://sponeil.net/downloads.htm) Camera position X=0, Y=0, Z=500. GroundFromSpace on the left, SkyFromSpace on the right. Camera position X=500, Y=500, Z=500. GroundFromSpace on the left, SkyFromSpace on the right. I've found that the camera angle seems to handled very differently depending the source: In the original shaders the camera angle in SkyFromSpaceShader is calculated as: float fCameraAngle = dot(v3Ray, v3SamplePoint) / fHeight; Whereas in ground from space shader the camera angle is calculated as: float fCameraAngle = dot(-v3Ray, v3Pos) / length(v3Pos); However, various sources online tinker with negating the ray. Why is this? Here is a C# Windows.Forms project that demonstrates the problem and that I've used to generate the images: https://github.com/ollipekka/AtmosphericScatteringTest/ Update: I have found out from the ScatterCPU project found on O'Neil's site that the camera ray is negated when the camera is above the point being shaded so that the scattering is calculated from point to the camera. Changing the ray direction indeed does remove artifacts, but introduces other problems as illustrated here: Furthermore, in the ScatterCPU project, O'Neil guards against situations where optical depth for light is less than zero: float fLightDepth = Scale(fLightAngle, fScaleDepth); if (fLightDepth < float.Epsilon) { continue; } As pointed out in the comments, along with these new artifacts this still leaves the question, what is wrong with the images where camera is positioned at 500, 500, 500? It feels like the halo is focused on completely wrong part of the planet. One would expect that the light would be closer to the spot where the sun should hits the planet, rather than where it changes from day to night. The github project has been updated to reflect changes in this update.

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  • grub problem after grub-repair

    - by alireza
    I had two OS,win 7 and Ubuntu, I was working with win and went out of the room and when came back I saw Grub Rescue!!! I booted live and did grub_repaire and it still says multiple active partitions.operating system not found I feel that it can not find the ubuntu hard drive at all! ! ubuntu@ubuntu:/dev$ sudo fdisk -l Disk /dev/sda: 320.1 GB, 320072933376 bytes 255 heads, 63 sectors/track, 38913 cylinders, total 625142448 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0xde771741 Device Boot Start End Blocks Id System /dev/sda1 * 61 61 0 0 Empty /dev/sda2 2048 30146559 15072256 27 Hidden NTFS WinRE /dev/sda3 * 30146560 30351359 102400 7 HPFS/NTFS/exFAT /dev/sda4 30351360 334483299 152065970 7 HPFS/NTFS/exFAT ubuntu@ubuntu:/dev$ ls autofs dvdrw loop4 ppp ram5 shm tty15 tty29 tty42 tty56 ttyS10 ttyS24 uinput vcsa1 block ecryptfs loop5 psaux ram6 snapshot tty16 tty3 tty43 tty57 ttyS11 ttyS25 urandom vcsa2 bsg fb0 loop6 ptmx ram7 snd tty17 tty30 tty44 tty58 ttyS12 ttyS26 usbmon0 vcsa3 btrfs-control fd loop7 pts ram8 sr0 tty18 tty31 tty45 tty59 ttyS13 ttyS27 usbmon1 vcsa4 bus full loop-control ram0 ram9 stderr tty19 tty32 tty46 tty6 ttyS14 ttyS28 usbmon2 vcsa5 cdrom fuse mapper ram1 random stdin tty2 tty33 tty47 tty60 ttyS15 ttyS29 v4l vcsa6 cdrw fw0 mcelog ram10 rfkill stdout tty20 tty34 tty48 tty61 ttyS16 ttyS3 vcs vcsa7 char hpet mei ram11 rtc tty tty21 tty35 tty49 tty62 ttyS17 ttyS30 vcs1 vga_arbiter console input mem ram12 rtc0 tty0 tty22 tty36 tty5 tty63 ttyS18 ttyS31 vcs2 video0 core kmsg net ram13 sda tty1 tty23 tty37 tty50 tty7 ttyS19 ttyS4 vcs3 zero cpu log network_latency ram14 sda2 tty10 tty24 tty38 tty51 tty8 ttyS2 ttyS5 vcs4 cpu_dma_latency loop0 network_throughput ram15 sda3 tty11 tty25 tty39 tty52 tty9 ttyS20 ttyS6 vcs5 disk loop1 null ram2 sda4 tty12 tty26 tty4 tty53 ttyprintk ttyS21 ttyS7 vcs6 dri loop2 oldmem ram3 sg0 tty13 tty27 tty40 tty54 ttyS0 ttyS22 ttyS8 vcs7 dvd loop3 port ram4 sg1 tty14 tty28 tty41 tty55 ttyS1 ttyS23 ttyS9 vcsa ubuntu@ubuntu:/dev$ someone said { Remove the boot flag from sda1, by typing in a terminal: sudo fdisk /dev/sda1 Then press the 'a' key, and 'Enter'. Then press the '1' key, and 'Enter'. Then press the 'w' key, and 'Enter'. } but after grub-repair I got this log: http://paste.ubuntu.com/1371297/ then I try sudo fdisk /dev/sda1 and But It says unable to open /dev/sda1! which is right as sda1 is not in dev folder (look at the picture!) Can anybody help me? I need to work on my windows for the rest of the semester and don't care of my ubuntu. thank you

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  • The Oracle Cash Management Secret Very Few Customers Know About

    - by Theresa Hickman
    Did you know that Oracle Cash Management has a robust positioning feature? I had no idea. I was under the mistaken impression that Oracle Cash Management only did bank statement reconciliations. It seems I am not alone. In fact, many Oracle Financials customers are also not aware of this even though it is delivered for free with the Oracle Financials license. Even better, last week, Oracle released an enhancement to Oracle Cash Management for Release 12 that will greatly help customers with their cash positioning needs. As we all know, credit is tight these days. Companies need better visibility of their cash and other liquidity positions to make better use of their cash resources. Today, many customers are managing their cash positions manually using spreadsheets. We also hear how many of them are maintaining larger than normal balances in numerous bank accounts because they just do not have the visibility, and therefore the comfort they need. Although spreadsheets may work in the short-term, they are not the best way to manage your cash positions for the long-term especially if you have dozens, or even hundreds of bank and brokerage accounts. Also, spreadsheets are a lot more risky because they can be overwritten, deleted, difficult to audit, etc. With the newly enhanced positioning feature in Oracle Cash Management, customers can manage their daily cash positions using an excel-like interface that is very flexible and user-configurable. You can link the worksheet to an unlimited number of bank accounts to automatically retrieve your opening balances, the current/intra-day cash inflows and outflows, as well as your expected cash flows from your Fx, Investment and Debt positions if you have Oracle's Treasury module . Oracle Cash Management also has direct integration with Oracle Receivables, Oracle Payables, and Payroll, which adds to the comprehensive picture of what's happening with your organizations' cash in real-time. Here's a screen shot of what the cash positioning page looks like: View image As you can see, your Treasurers can obtain a holistic view of all cash positions across any number of bank accounts as well as other sources of cash flow movements. Depending on how they manage their accounts, they can also use this feature to initiate or monitor bank account sweeps or transfers between their zero balance accounts (ZBA) or cash pools. The cash position worksheet provide drill down for more detail and the ability to manually enter items directly into the worksheet for even greater flexibility and control. The enhancements to this feature were released last week. The following list the patches for Release 12.0.6 and 12.1.1: For more information, visit the following website. http://launch.oracle.com. PIN: yes2try

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  • Tips on ensuring Model Quality

    - by [email protected]
    Given enough data that represents well the domain and models that reflect exactly the decision being optimized, models usually provide good predictions that ensure lift. Nevertheless, sometimes the modeling situation is less than ideal. In this blog entry we explore the problems found in a few such situations and how to avoid them.1 - The Model does not reflect the problem you are trying to solveFor example, you may be trying to solve the problem: "What product should I recommend to this customer" but your model learns on the problem: "Given that a customer has acquired our products, what is the likelihood for each product". In this case the model you built may be too far of a proxy for the problem you are really trying to solve. What you could do in this case is try to build a model based on the result from recommendations of products to customers. If there is not enough data from actual recommendations, you could use a hybrid approach in which you would use the [bad] proxy model until the recommendation model converges.2 - Data is not predictive enoughIf the inputs are not correlated with the output then the models may be unable to provide good predictions. For example, if the input is the phase of the moon and the weather and the output is what car did the customer buy, there may be no correlations found. In this case you should see a low quality model.The solution in this case is to include more relevant inputs.3 - Not enough cases seenIf the data learned does not include enough cases, at least 200 positive examples for each output, then the quality of recommendations may be low. The obvious solution is to include more data records. If this is not possible, then it may be possible to build a model based on the characteristics of the output choices rather than the choices themselves. For example, instead of using products as output, use the product category, price and brand name, and then combine these models.4 - Output leaking into input giving the false impression of good quality modelsIf the input data in the training includes values that have changed or are available only because the output happened, then you will find some strong correlations between the input and the output, but these strong correlations do not reflect the data that you will have available at decision (prediction) time. For example, if you are building a model to predict whether a web site visitor will succeed in registering, and the input includes the variable DaysSinceRegistration, and you learn when this variable has already been set, you will probably see a big correlation between having a Zero (or one) in this variable and the fact that registration was successful.The solution is to remove these variables from the input or make sure they reflect the value as of the time of decision and not after the result is known. 

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  • Programming Windows 8 Apps with HTML, CSS, and JavaScript - All you need in one title

    It took me a while to work through the 800+ pages of this title. And yes, I really mean working not reading... Since the release of Windows 8 it should be obvious to any Windows software developer that there are new ways to develop, deploy and market applications for a broader audience. Interestingly, Microsoft started to narrow the technological gap between the various platforms - desktop, web, smartphone and XBox - and development of modern apps with HTML, CSS and JavaScript couldn't be easier. Kraig covers all facets of modern Windows 8 apps from the basic building blocks and project templates in Visual Studio 2012 over to the thoughtful use of specific APIs to finally proper deployment in the App Store and potential monetization. The organisation of the book is lied out like step by step instructions or a tutorial. Kraig literally takes the reader by the hand and explains in detail in his examples about the reasons, the pros, and the cons of a certain way of implementation. Thanks to cross-references to other chapters he leaves the choice to the reader to dig deeper right now or to catch up at some time later. Personally, I have to admit that I really enjoyed the relaxed writing style. App development is not dust-dry rocket science and it should be joyful to learn about new technologies. And thanks to the richness of the various chapters and samples you could easily adapt and transfer the knowledge gained in this title to other platforms like Windows Phone 8. And last but not least: The ebook is freely available at Amazon, Microsoft Press and O'Reilly. Don't think about it, just get the book. Now. Update: I already mentioned this title in other blog entries which are related to Microsoft certification. Feel free to read on and to discover more online resources: Learning content for MCSDs: Web Applications and Windows Store Apps using HTML5 More content for MCSDs: Web Applications and Windows Store Apps using HTML5 O'Reilly offers free webcasts on their site, too. And in case that you would like to know more about Kraig's book and his experience with various development teams, please checkout this one: Zero to App in Two Weeks: Programming Windows 8 Apps in HTML, CSS, and JavaScript. The recording should be available soon.

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  • Given the presentation model pattern, is the view, presentation model, or model responsible for adding child views to an existing view at runtime?

    - by Ryan Taylor
    I am building a Flex 4 based application using the presentation model design pattern. This application will have several different components to it as shown in the image below. The MainView and DashboardView will always be visible and they each have corresponding presentation models and models as necessary. These views are easily created by declaring their MXML in the application root. <s:HGroup width="100%" height="100%"> <MainView width="75% height="100%"/> <DashboardView width="25%" height="100%"/> </s:HGroup> There will also be many WidgetViewN views that can be added to the DashboardView by the user at runtime through a simple drop down list. This will need to be accomplished via ActionScript. The drop down list should always show what WidgetViewN has already been added to the DashboardView. Therefore some state about which WidgetViewN's have been created needs to be stored. Since the list of available WidgetViewN and which ones are added to the DashboardView also need to be accessible from other components in the system I think this needs to be stored in a Model object. My understanding of the presentation model design pattern is that the view is very lean. It contains as close to zero logic as is practical. The view communicates/binds to the presentation model which contains all the necessary view logic. The presentation model is effectively an abstract representation of the view which supports low coupling and eases testability. The presentation model may have one or more models injected in in order to display the necessary information. The models themselves contain no view logic whatsoever. So I have a several questions around this design. Who should be responsible for creating the WidgetViewN components and adding these to the DashboardView? Is this the responsibility of the DashboardView, DashboardPresentationModel, DashboardModel or something else entirely? It seems like the DashboardPresentationModel would be responsible for creating/adding/removing any child views from it's display but how do you do this without passing in the DashboardView to the DashboardPresentationModel? The list of available and visible WidgetViewN components needs to be accessible to a few other components as well. Is it okay for a reference to a WidgetViewN to be stored/referenced in a model? Are there any good examples of the presentation model pattern online in Flex that also include creating child views at runtime?

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  • Fast programmatic compare of "timetable" data

    - by Brendan Green
    Consider train timetable data, where each service (or "run") has a data structure as such: public class TimeTable { public int Id {get;set;} public List<Run> Runs {get;set;} } public class Run { public List<Stop> Stops {get;set;} public int RunId {get;set;} } public class Stop { public int StationId {get;set;} public TimeSpan? StopTime {get;set;} public bool IsStop {get;set;} } We have a list of runs that operate against a particular line (the TimeTable class). Further, whilst we have a set collection of stations that are on a line, not all runs stop at all stations (that is, IsStop would be false, and StopTime would be null). Now, imagine that we have received the initial timetable, processed it, and loaded it into the above data structure. Once the initial load is complete, it is persisted into a database - the data structure is used only to load the timetable from its source and to persist it to the database. We are now receiving an updated timetable. The updated timetable may or may not have any changes to it - we don't know and are not told whether any changes are present. What I would like to do is perform a compare for each run in an efficient manner. I don't want to simply replace each run. Instead, I want to have a background task that runs periodically that downloads the updated timetable dataset, and then compares it to the current timetable. If differences are found, some action (not relevant to the question) will take place. I was initially thinking of some sort of checksum process, where I could, for example, load both runs (that is, the one from the new timetable received and the one that has been persisted to the database) into the data structure and then add up all the hour components of the StopTime, and all the minute components of the StopTime and compare the results (i.e. both the sum of Hours and sum of Minutes would be the same, and differences introduced if a stop time is changed, a stop deleted or a new stop added). Would that be a valid way to check for differences, or is there a better way to approach this problem? I can see a problem that, for example, one stop is changed to be 2 minutes earlier, and another changed to be 2 minutes later would have a net zero change. Or am I over thinking this, and would it just be simpler to brute check all stops to ensure that The updated run stops at the same stations; and Each stop is at the same time

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  • Video stutter when using external drive

    - by psion
    When using boxee to play video files off of an external western digital 1TB drive formatted NTFS, I notice a slight stutter in the video every 5-10 seconds. When using mplayer, it doesn't stutter as often, but it still stutters occasionally. If I play the video off of the local sata drive, it plays fine even in boxee. I use this computer as my HTPC and I just switched from windows to linux on it. In windows, I never had any sort of stutter playing movies from the drive. I am using the latest intel graphics drivers (for the intel GMA 950) root@eee-htpc:/home/htpc# grep wd /etc/mtab /dev/sdb1 /mnt/wd2 fuseblk rw,nosuid,nodev,allow_other,blksize=512 0 0 I notice that despite trying to use ntfs or ntfs-3g, ubuntu uses ntfs-fuse which I've heard is slower. /dev/sdb1: Timing buffered disk reads: 80 MB in 3.07 seconds = 26.08 MB/sec root@eee-htpc:/mnt/wd2# dd if=/dev/zero of=./120mb bs=1024 count=120000 root@eee-htpc:/mnt/wd2# time mv ./120mb /home/htpc real 0m2.095s user 0m0.016s sys 0m0.736s Even though fuse has a reputation for being slow, it should easily be fast enough for playing standard definition video files. So why the video stutter? edit: The issue seems to be overhead cpu usage from either playing off of a usb device or ntfs/fuse. Watching CPU usage with top, local files use 10-40% CPU. Watching the same video on the external formatted ntfs, it spikes to 170% (over 100% because of hyperthreading). To me it seems like it must be overhead from the fuse driver, though I don't know if it has more or less overhead than ntfs-3g. It's a EEEBox B202 that has an atom 270, so not exactly the most powerful out there. edit2: I believe the solution would be to use non-fuse drivers or different fuse drivers. so far I have not been able to. edit3: I've probably edited this more times than I should, but as an update I have upgraded ntfs drivers to ntfs-3g 2010.8.8 external FUSE 28 - Third Generation NTFS Driver using the following PPA - ppa:x3lectric/team-iquik-releases. When first opening a video file in boxee that's on ntfs there's still the same amount of lag. After a few minutes of video, the lag seems to go away and the cpu usage comes down to 10-40%. Every so often though, it begins to stutter again. Also, if I skip ahead/back in the file, it begins to stutter a lot.

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  • Using the jQuery UI Library in a MVC 3 Application to Build a Dialog Form

    - by ChrisD
    Using a simulated dialog window is a nice way to handle inline data editing. The jQuery UI has a UI widget for a dialog window that makes it easy to get up and running with it in your application. With the release of ASP.NET MVC 3, Microsoft included the jQuery UI scripts and files in the MVC 3 project templates for Visual Studio. With the release of the MVC 3 Tools Update, Microsoft implemented the inclusion of those with NuGet as packages. That means we can get up and running using the latest version of the jQuery UI with minimal effort. To the code! Another that might interested you about JQuery Mobile and ASP.NET MVC 3 with C#. If you are starting with a new MVC 3 application and have the Tools Update then you are a NuGet update and a <link> and <script> tag away from adding the jQuery UI to your project. If you are using an existing MVC project you can still get the jQuery UI library added to your project via NuGet and then add the link and script tags. Assuming that you have pulled down the latest version (at the time of this publish it was 1.8.13) you can add the following link and script tags to your <head> tag: < link href = "@Url.Content(" ~ / Content / themes / base / jquery . ui . all . css ")" rel = "Stylesheet" type = "text/css" /> < script src = "@Url.Content(" ~ / Scripts / jquery-ui-1 . 8 . 13 . min . js ")" type = "text/javascript" ></ script > The jQuery UI library relies upon the CSS scripts and some image files to handle rendering of its widgets (you can choose a different theme or role your own if you like). Adding these to the stock _Layout.cshtml file results in the following markup: <!DOCTYPE html> < html > < head >     < meta charset = "utf-8" />     < title > @ViewBag.Title </ title >     < link href = "@Url.Content(" ~ / Content / Site . css ")" rel = "stylesheet" type = "text/css" />     <link href="@Url.Content("~/Content/themes/base/jquery.ui.all.css")" rel="Stylesheet" type="text/css" />     <script src="@Url.Content("~/Scripts/jquery-1.5.1.min.js")" type="text/javascript"></script>     <script src="@Url.Content("~/Scripts/modernizr-1.7.min . js ")" type = "text/javascript" ></ script >     < script src = "@Url.Content(" ~ / Scripts / jquery-ui-1 . 8 . 13 . min . js ")" type = "text/javascript" ></ script > </ head > < body >     @RenderBody() </ body > </ html > Our example will involve building a list of notes with an id, title and description. Each note can be edited and new notes can be added. The user will never have to leave the single page of notes to manage the note data. The add and edit forms will be delivered in a jQuery UI dialog widget and the note list content will get reloaded via an AJAX call after each change to the list. To begin, we need to craft a model and a data management class. We will do this so we can simulate data storage and get a feel for the workflow of the user experience. The first class named Note will have properties to represent our data model. namespace Website . Models {     public class Note     {         public int Id { get ; set ; }         public string Title { get ; set ; }         public string Body { get ; set ; }     } } The second class named NoteManager will be used to set up our simulated data storage and provide methods for querying and updating the data. We will take a look at the class content as a whole and then walk through each method after. using System . Collections . ObjectModel ; using System . Linq ; using System . Web ; namespace Website . Models {     public class NoteManager     {         public Collection < Note > Notes         {             get             {                 if ( HttpRuntime . Cache [ "Notes" ] == null )                     this . loadInitialData ();                 return ( Collection < Note >) HttpRuntime . Cache [ "Notes" ];             }         }         private void loadInitialData ()         {             var notes = new Collection < Note >();             notes . Add ( new Note                           {                               Id = 1 ,                               Title = "Set DVR for Sunday" ,                               Body = "Don't forget to record Game of Thrones!"                           });             notes . Add ( new Note                           {                               Id = 2 ,                               Title = "Read MVC article" ,                               Body = "Check out the new iwantmymvc.com post"                           });             notes . Add ( new Note                           {                               Id = 3 ,                               Title = "Pick up kid" ,                               Body = "Daughter out of school at 1:30pm on Thursday. Don't forget!"                           });             notes . Add ( new Note                           {                               Id = 4 ,                               Title = "Paint" ,                               Body = "Finish the 2nd coat in the bathroom"                           });             HttpRuntime . Cache [ "Notes" ] = notes ;         }         public Collection < Note > GetAll ()         {             return Notes ;         }         public Note GetById ( int id )         {             return Notes . Where ( i => i . Id == id ). FirstOrDefault ();         }         public int Save ( Note item )         {             if ( item . Id <= 0 )                 return saveAsNew ( item );             var existingNote = Notes . Where ( i => i . Id == item . Id ). FirstOrDefault ();             existingNote . Title = item . Title ;             existingNote . Body = item . Body ;             return existingNote . Id ;         }         private int saveAsNew ( Note item )         {             item . Id = Notes . Count + 1 ;             Notes . Add ( item );             return item . Id ;         }     } } The class has a property named Notes that is read only and handles instantiating a collection of Note objects in the runtime cache if it doesn't exist, and then returns the collection from the cache. This property is there to give us a simulated storage so that we didn't have to add a full blown database (beyond the scope of this post). The private method loadInitialData handles pre-filling the collection of Note objects with some initial data and stuffs them into the cache. Both of these chunks of code would be refactored out with a move to a real means of data storage. The GetAll and GetById methods access our simulated data storage to return all of our notes or a specific note by id. The Save method takes in a Note object, checks to see if it has an Id less than or equal to zero (we assume that an Id that is not greater than zero represents a note that is new) and if so, calls the private method saveAsNew . If the Note item sent in has an Id , the code finds that Note in the simulated storage, updates the Title and Description , and returns the Id value. The saveAsNew method sets the Id , adds it to the simulated storage, and returns the Id value. The increment of the Id is simulated here by getting the current count of the note collection and adding 1 to it. The setting of the Id is the only other chunk of code that would be refactored out when moving to a different data storage approach. With our model and data manager code in place we can turn our attention to the controller and views. We can do all of our work in a single controller. If we use a HomeController , we can add an action method named Index that will return our main view. An action method named List will get all of our Note objects from our manager and return a partial view. We will use some jQuery to make an AJAX call to that action method and update our main view with the partial view content returned. Since the jQuery AJAX call will cache the call to the content in Internet Explorer by default (a setting in jQuery), we will decorate the List, Create and Edit action methods with the OutputCache attribute and a duration of 0. This will send the no-cache flag back in the header of the content to the browser and jQuery will pick that up and not cache the AJAX call. The Create action method instantiates a new Note model object and returns a partial view, specifying the NoteForm.cshtml view file and passing in the model. The NoteForm view is used for the add and edit functionality. The Edit action method takes in the Id of the note to be edited, loads the Note model object based on that Id , and does the same return of the partial view as the Create method. The Save method takes in the posted Note object and sends it to the manager to save. It is decorated with the HttpPost attribute to ensure that it will only be available via a POST. It returns a Json object with a property named Success that can be used by the UX to verify everything went well (we won't use that in our example). Both the add and edit actions in the UX will post to the Save action method, allowing us to reduce the amount of unique jQuery we need to write in our view. The contents of the HomeController.cs file: using System . Web . Mvc ; using Website . Models ; namespace Website . Controllers {     public class HomeController : Controller     {         public ActionResult Index ()         {             return View ();         }         [ OutputCache ( Duration = 0 )]         public ActionResult List ()         {             var manager = new NoteManager ();             var model = manager . GetAll ();             return PartialView ( model );         }         [ OutputCache ( Duration = 0 )]         public ActionResult Create ()         {             var model = new Note ();             return PartialView ( "NoteForm" , model );         }         [ OutputCache ( Duration = 0 )]         public ActionResult Edit ( int id )         {             var manager = new NoteManager ();             var model = manager . GetById ( id );             return PartialView ( "NoteForm" , model );         }         [ HttpPost ]         public JsonResult Save ( Note note )         {             var manager = new NoteManager ();             var noteId = manager . Save ( note );             return Json ( new { Success = noteId > 0 });         }     } } The view for the note form, NoteForm.cshtml , looks like so: @model Website . Models . Note @using ( Html . BeginForm ( "Save" , "Home" , FormMethod . Post , new { id = "NoteForm" })) { @Html . Hidden ( "Id" ) < label class = "Title" >     < span > Title < /span><br / >     @Html . TextBox ( "Title" ) < /label> <label class="Body">     <span>Body</ span >< br />     @Html . TextArea ( "Body" ) < /label> } It is a strongly typed view for our Note model class. We give the <form> element an id attribute so that we can reference it via jQuery. The <label> and <span> tags give our UX some structure that we can style with some CSS. The List.cshtml view is used to render out a <ul> element with all of our notes. @model IEnumerable < Website . Models . Note > < ul class = "NotesList" >     @foreach ( var note in Model )     {     < li >         @note . Title < br />         @note . Body < br />         < span class = "EditLink ButtonLink" noteid = "@note.Id" > Edit < /span>     </ li >     } < /ul> This view is strongly typed as well. It includes a <span> tag that we will use as an edit button. We add a custom attribute named noteid to the <span> tag that we can use in our jQuery to identify the Id of the note object we want to edit. The view, Index.cshtml , contains a bit of html block structure and all of our jQuery logic code. @ {     ViewBag . Title = "Index" ; } < h2 > Notes < /h2> <div id="NoteListBlock"></ div > < span class = "AddLink ButtonLink" > Add New Note < /span> <div id="NoteDialog" title="" class="Hidden"></ div > < script type = "text/javascript" >     $ ( function () {         $ ( "#NoteDialog" ). dialog ({             autoOpen : false , width : 400 , height : 330 , modal : true ,             buttons : {                 "Save" : function () {                     $ . post ( "/Home/Save" ,                         $ ( "#NoteForm" ). serialize (),                         function () {                             $ ( "#NoteDialog" ). dialog ( "close" );                             LoadList ();                         });                 },                 Cancel : function () { $ ( this ). dialog ( "close" ); }             }         });         $ ( ".EditLink" ). live ( "click" , function () {             var id = $ ( this ). attr ( "noteid" );             $ ( "#NoteDialog" ). html ( "" )                 . dialog ( "option" , "title" , "Edit Note" )                 . load ( "/Home/Edit/" + id , function () { $ ( "#NoteDialog" ). dialog ( "open" ); });         });         $ ( ".AddLink" ). click ( function () {             $ ( "#NoteDialog" ). html ( "" )                 . dialog ( "option" , "title" , "Add Note" )                 . load ( "/Home/Create" , function () { $ ( "#NoteDialog" ). dialog ( "open" ); });         });         LoadList ();     });     function LoadList () {         $ ( "#NoteListBlock" ). load ( "/Home/List" );     } < /script> The <div> tag with the id attribute of "NoteListBlock" is used as a container target for the load of the partial view content of our List action method. It starts out empty and will get loaded with content via jQuery once the DOM is loaded. The <div> tag with the id attribute of "NoteDialog" is the element for our dialog widget. The jQuery UI library will use the title attribute for the text in the dialog widget top header bar. We start out with it empty here and will dynamically change the text via jQuery based on the request to either add or edit a note. This <div> tag is given a CSS class named "Hidden" that will set the display:none style on the element. Since our call to the jQuery UI method to make the element a dialog widget will occur in the jQuery document ready code block, the end user will see the <div> element rendered in their browser as the page renders and then it will hide after that jQuery call. Adding the display:hidden to the <div> element via CSS will ensure that it is never rendered until the user triggers the request to open the dialog. The jQuery document load block contains the setup for the dialog node, click event bindings for the edit and add links, and a call to a JavaScript function called LoadList that handles the AJAX call to the List action method. The .dialog() method is called on the "NoteDialog" <div> element and the options are set for the dialog widget. The buttons option defines 2 buttons and their click actions. The first is the "Save" button (the text in quotations is used as the text for the button) that will do an AJAX post to our Save action method and send the serialized form data from the note form (targeted with the id attribute "NoteForm"). Upon completion it will close the dialog widget and call the LoadList to update the UX without a redirect. The "Cancel" button simply closes the dialog widget. The .live() method handles binding a function to the "click" event on all elements with the CSS class named EditLink . We use the .live() method because it will catch and bind our function to elements even as the DOM changes. Since we will be constantly changing the note list as we add and edit we want to ensure that the edit links get wired up with click events. The function for the click event on the edit links gets the noteid attribute and stores it in a local variable. Then it clears out the HTML in the dialog element (to ensure a fresh start), calls the .dialog() method and sets the "title" option (this sets the title attribute value), and then calls the .load() AJAX method to hit our Edit action method and inject the returned content into the "NoteDialog" <div> element. Once the .load() method is complete it opens the dialog widget. The click event binding for the add link is similar to the edit, only we don't need to get the id value and we load the Create action method. This binding is done via the .click() method because it will only be bound on the initial load of the page. The add button will always exist. Finally, we toss in some CSS in the Content/Site.css file to style our form and the add/edit links. . ButtonLink { color : Blue ; cursor : pointer ; } . ButtonLink : hover { text - decoration : underline ; } . Hidden { display : none ; } #NoteForm label { display:block; margin-bottom:6px; } #NoteForm label > span { font-weight:bold; } #NoteForm input[type=text] { width:350px; } #NoteForm textarea { width:350px; height:80px; } With all of our code in place we can do an F5 and see our list of notes: If we click on an edit link we will get the dialog widget with the correct note data loaded: And if we click on the add new note link we will get the dialog widget with the empty form: The end result of our solution tree for our sample:

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  • ray collision with rectangle and floating point accuracy

    - by phq
    I'm trying to solve a problem with a ray bouncing on a box. Actually it is a sphere but for simplicity the box dimensions are expanded by the sphere radius when doing the collision test making the sphere a single ray. It is done by projecting the ray onto all faces of the box and pick the one that is closest. However because I'm using floating point variables I fear that the projected point onto the surface might be interpreted as being below in the next iteration, also I will later allow the sphere to move which might make that scenario more likely. Also the bounce coefficient might be as low as zero, making the sphere continue along the surface. So my naive solution is to project not only forwards but backwards to catch those cases. That is where I got into problems shown in the figure: In the first iteration the first black arrow is calculated and we end up at a point on the surface of the box. In the second iteration the "back projection" hits the other surface making the second black arrow bounce on the wrong surface. If there are several boxes close to each other this has further consequences making the sphere fall through them all. So my main question is how to handle possible floating point accuracy when placing the sphere on the box surface so it does not fall through. In writing this question I got the idea to have a threshold to only accept back projections a certain amount much smaller than the box but larger than the possible accuracy limitation, this would only cause the "false" back projection when the sphere hit the box on an edge which would appear naturally. To clarify my original approach, the arrows shown in the image is not only the path the sphere travels but is also representing a single time step in the simulation. In reality the time step is much smaller about 0.05 of the box size. The path traveled is projected onto possible sides to avoid traveling past a thinner object at higher speeds. In normal situations the floating point accuracy is not an issue but there are two situations where I have the concern. When the new position at the end of the time step is located very close to the surface, very unlikely though. When using a bounce factor of 0, here it happens every time the sphere hit a box. To add some loss of accuracy, the motivation for my concern, is that the sphere and box are in different coordinate systems and thus the sphere location is transformed for every test. This last one is why I'm not willing to stand on luck that one floating point value lying on top of the box always will be interpreted the same. I did not know voronoi regions by name, but looking at it I'm not sure how it would be used in a projection scenario that I'm using here.

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  • GUVCVIEW errors

    - by Brian Snapp
    I had GUVCVIEW working once before. it suddenly quit working. This is the error I receive........ bt_audio_service_open: connect() failed: Connection refused (111) bt_audio_service_open: connect() failed: Connection refused (111) bt_audio_service_open: connect() failed: Connection refused (111) bt_audio_service_open: connect() failed: Connection refused (111) video device: /dev/video0 /dev/video0 - device 1 Init. Intergrated Webcam (location: usb-0000:00:1a.7-2) { pixelformat = 'YUYV', description = 'YUV 4:2:2 (YUYV)' } { discrete: width = 640, height = 480 } Time interval between frame: 1/30, 1/20, 1/15, 1/10, 1/5, { discrete: width = 352, height = 288 } Time interval between frame: 1/30, 1/20, 1/15, 1/10, 1/5, { discrete: width = 320, height = 240 } Time interval between frame: 1/30, 1/20, 1/15, 1/10, 1/5, { discrete: width = 176, height = 144 } Time interval between frame: 1/30, 1/20, 1/15, 1/10, 1/5, { discrete: width = 160, height = 120 } Time interval between frame: 1/30, 1/20, 1/15, 1/10, 1/5, { discrete: width = 1024, height = 768 } Time interval between frame: 1/9, 1/5, { discrete: width = 1280, height = 1024 } Time interval between frame: 1/9, 1/5, checking format: 1196444237 Format unavailable: 1196444237. Init v4L2 failed !! Init video returned -2 trying minimum setup ... video device: /dev/video0 /dev/video0 - device 1 Init. Intergrated Webcam (location: usb-0000:00:1a.7-2) { pixelformat = 'YUYV', description = 'YUV 4:2:2 (YUYV)' } { discrete: width = 640, height = 480 } Time interval between frame: 1/30, 1/20, 1/15, 1/10, 1/5, { discrete: width = 352, height = 288 } Time interval between frame: 1/30, 1/20, 1/15, 1/10, 1/5, { discrete: width = 320, height = 240 } Time interval between frame: 1/30, 1/20, 1/15, 1/10, 1/5, { discrete: width = 176, height = 144 } Time interval between frame: 1/30, 1/20, 1/15, 1/10, 1/5, { discrete: width = 160, height = 120 } Time interval between frame: 1/30, 1/20, 1/15, 1/10, 1/5, { discrete: width = 1024, height = 768 } Time interval between frame: 1/9, 1/5, { discrete: width = 1280, height = 1024 } Time interval between frame: 1/9, 1/5, checking format: 1448695129 Requested Format unavailable: get width 640 height 480 vid:0c45 pid:6410 driver:uvcvideo (guvcview:4079): Gtk-CRITICAL **: gtk_hscale_new_with_range: assertion `min < max' failed (guvcview:4079): Gtk-CRITICAL **: gtk_scale_set_draw_value: assertion `GTK_IS_SCALE (scale)' failed Segmentation fault I suppose the problem lies in the fact, that I cannot locate a configuration file to edit. Any help in where this file may lie? I have tried searching for any/everything related to guvcview, and have had zero success. Thank you for taking the time to read this, and hopefully providing a solution..

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  • Arrive steering behavior

    - by dbostream
    I bought a book called Programming game AI by example and I am trying to implement the arrive steering behavior. The problem I am having is that my objects oscillate around the target position; after oscillating less and less for awhile they finally come to a stop at the target position. Does anyone have any idea why this oscillating behavior occur? Since the examples accompanying the book are written in C++ I had to rewrite the code into C#. Below is the relevant parts of the steering behavior: private enum Deceleration { Fast = 1, Normal = 2, Slow = 3 } public MovingEntity Entity { get; private set; } public Vector2 SteeringForce { get; private set; } public Vector2 Target { get; set; } public Vector2 Calculate() { SteeringForce.Zero(); SteeringForce = SumForces(); SteeringForce.Truncate(Entity.MaxForce); return SteeringForce; } private Vector2 SumForces() { Vector2 force = new Vector2(); if (Activated(BehaviorTypes.Arrive)) { force += Arrive(Target, Deceleration.Slow); if (!AccumulateForce(force)) return SteeringForce; } return SteeringForce; } private Vector2 Arrive(Vector2 target, Deceleration deceleration) { Vector2 toTarget = target - Entity.Position; double distance = toTarget.Length(); if (distance > 0) { //because Deceleration is enumerated as an int, this value is required //to provide fine tweaking of the deceleration.. double decelerationTweaker = 0.3; double speed = distance / ((double)deceleration * decelerationTweaker); speed = Math.Min(speed, Entity.MaxSpeed); Vector2 desiredVelocity = toTarget * speed / distance; return desiredVelocity - Entity.Velocity; } return new Vector2(); } private bool AccumulateForce(Vector2 forceToAdd) { double magnitudeRemaining = Entity.MaxForce - SteeringForce.Length(); if (magnitudeRemaining <= 0) return false; double magnitudeToAdd = forceToAdd.Length(); if (magnitudeToAdd > magnitudeRemaining) magnitudeToAdd = magnitudeRemaining; SteeringForce += Vector2.NormalizeRet(forceToAdd) * magnitudeToAdd; return true; } This is the update method of my objects: public void Update(double deltaTime) { Vector2 steeringForce = Steering.Calculate(); Vector2 acceleration = steeringForce / Mass; Velocity = Velocity + acceleration * deltaTime; Velocity.Truncate(MaxSpeed); Position = Position + Velocity * deltaTime; } If you want to see the problem with your own eyes you can download a minimal example here. Thanks in advance.

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  • x axis detection issues platformer starter kit

    - by dbomb101
    I've come across a problem with the collision detection code in the platformer starter kit for xna.It will send up the impassible flag on the x axis despite being nowhere near a wall in either direction on the x axis, could someone could tell me why this happens ? Here is the collision method. /// <summary> /// Detects and resolves all collisions between the player and his neighboring /// tiles. When a collision is detected, the player is pushed away along one /// axis to prevent overlapping. There is some special logic for the Y axis to /// handle platforms which behave differently depending on direction of movement. /// </summary> private void HandleCollisions() { // Get the player's bounding rectangle and find neighboring tiles. Rectangle bounds = BoundingRectangle; int leftTile = (int)Math.Floor((float)bounds.Left / Tile.Width); int rightTile = (int)Math.Ceiling(((float)bounds.Right / Tile.Width)) - 1; int topTile = (int)Math.Floor((float)bounds.Top / Tile.Height); int bottomTile = (int)Math.Ceiling(((float)bounds.Bottom / Tile.Height)) - 1; // Reset flag to search for ground collision. isOnGround = false; // For each potentially colliding tile, for (int y = topTile; y <= bottomTile; ++y) { for (int x = leftTile; x <= rightTile; ++x) { // If this tile is collidable, TileCollision collision = Level.GetCollision(x, y); if (collision != TileCollision.Passable) { // Determine collision depth (with direction) and magnitude. Rectangle tileBounds = Level.GetBounds(x, y); Vector2 depth = RectangleExtensions.GetIntersectionDepth(bounds, tileBounds); if (depth != Vector2.Zero) { float absDepthX = Math.Abs(depth.X); float absDepthY = Math.Abs(depth.Y); // Resolve the collision along the shallow axis. if (absDepthY < absDepthX || collision == TileCollision.Platform) { // If we crossed the top of a tile, we are on the ground. if (previousBottom <= tileBounds.Top) isOnGround = true; // Ignore platforms, unless we are on the ground. if (collision == TileCollision.Impassable || IsOnGround) { // Resolve the collision along the Y axis. Position = new Vector2(Position.X, Position.Y + depth.Y); // Perform further collisions with the new bounds. bounds = BoundingRectangle; } } //This is the section which deals with collision on the x-axis else if (collision == TileCollision.Impassable) // Ignore platforms. { // Resolve the collision along the X axis. Position = new Vector2(Position.X + depth.X, Position.Y); // Perform further collisions with the new bounds. bounds = BoundingRectangle; } } } } } // Save the new bounds bottom. previousBottom = bounds.Bottom; }

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  • Oracle Gave Me a Chance - ECEMEA Internship Programme

    - by FelixWehmeyer
    My name is Mohammad Raad and I started in the One Year Training program with Oracle on March 1, 2012. I graduated on September 2011 and started searching for a job. Starting your career, as you all know, is hard because some companies see you as a fresh graduate lacking experience and no one is willing to invest in you. I used to check the recruitment websites daily to see if there were openings to apply to, but unfortunately no one wanted to hire a zero year experience fresh graduate. One day I saw Oracle’s 1 year internship program advertised and that was what I needed. I applied but expected nothing to happen because I was used to applying and getting no replies, but they called and that was the start! I had my first interview over the phone and decided to go to Qatar and to continue to search for a job. Two weeks after arriving at Qatar, Oracle called me for a second interview in Lebanon so I booked a ticket on the same day because my interview was the next day I had my interview and went back to Qatar. On January 2012, I heard from Oracle that I was accepted and they choose me for this program, it was a day I will not forget! Starting on 1st March 2012, I was full of energy, willing to do anything to gain experience and prove that I can do it. What really give me a big push is my colleagues’ motivation and support especially from Youssef Halawi, my mentor and Rami Mattar because they believe in me and track my progress day-by-day. At Oracle, I meet customers, attend meetings, demos and presentations, partners’ events and online trainings. Now I’m focusing on a specific product that I really liked and aim to master by the end of my internship. So dear readers wish me good luck! I know that I will get the experience that I want, because from Oracle, a leader in its industry, you have the chance to grab experience as much as you can handle, simply because there are no limits to excellence. Do you want to find out more about the open roles within Oracle? Follow us on https://campus.oracle.com.

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  • GUI device for throwing a ball

    - by Fredrik Johansson
    The hero has a ball, which shall be thrown with accuracy in a court on iPhone/iPad. The player is seen from above, in a 2D view. In game play, the player reach is between 1/15 and 1/6 of the height of the iPhone screen. The player will run, and try to outmaneuver his opponent, and then throw the ball at a specific location, which is guarded by the opponent (which is also shown on the screen). The player is controlled by a joystick, and that works ok, but how shall I control the stick? Maybe someone can propose a third control method? I've tried the following two approaches: Joystick: Hero has a reach of 1 meter, and this reach is marked with a semi-opaque circle around the player. The ball can be moved by a joystick. When the joystick is moved south, the ball is moved south within the reach circle. There is a direct coupling with the joystick and the position of the ball. I.e. when the joystick is moved max south, the ball is max south within the player reach. At each touch update the speed is calculated, and the Box2d ball position and ball speed are updated. NB, the ball will never be moved outside the reach as long as the player push the joystick. The ball is thrown by swiping the joystick to make the ball move, and then releasing the joystick. At release, the ball will get a smoothed speed of the joystick. Joystick Problem: The throwing accuracy gets bad, because the joystick can not be that big, and a small movement results in quite a large movement of the ball. If the user does not release before the end of the joystick maximum end point, the ball will stop, and when the user releases the joystick the speed of the ball will be zero. Bad... Touch pad A force is applied to the ball by a sweep on a touchpad. The ball is released when the sweep is ended, or when the ball is moved outside the player reach. As there is no one to one mapping between the swipe and the ball position, the precision can be improved. A large swipe can result in a small ball movement. Touch Pad Problem A touchpad is less intuitive. Users do not seem to know what to do with the touch pad. Some tap the touchpad, and then the ball just falls to the ground. As there is no one-to-one mapping, the ball can be moved outside the reach, and then it will just fall to the ground. It's a bit hard to control the ball, especially if the player also moves.

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  • Where Are You on the Visualization Maturity Curve?

    - by Celine Beck
    The old phrase “A picture is worth a thousand words” is as true now as ever. Providing the right users with access to the right product data, at the right time, can provide significant benefits to a business. This is especially evident with increasing technical and product complexities, elongated supply chains, and growing pressure to bring innovative products to market faster. With this in mind, it is easy to understand why visualization is an integral part of any successful product lifecycle management (PLM) strategy. At a bare minimum, knowledge workers use multiple individual documents of different formats and structure, and leverage visualization solutions to access information; but the real value of visualization can be fully reaped when it is connected to enterprise applications like PLM and tied to the appropriate business context. The picture below illustrates this visualization maturity curve, as we presented during the last Oracle Open World and the transformational effect that visualization can have on PLM processes and performance (check out the post about AutoVue Key Highlights from Oracle Open World 2012 for more information). Organizations are likely to see greater positive impact on business performance when visualization is connected to enterprise systems, allowing access to information coming from multiple sources, such as PLM, supply chain management (SCM) and enterprise resource planning (ERP). This allows organizations to reach higher levels of collaboration and optimize decision-making capacity as users can benefit from in-context access to visual information. For instance, within a PLM system, a design engineer can access a product assembly and review digital annotations added by other users specific to the engineering change request he is reviewing rather than all historical annotations. The last stage on the curve is what we call augmented business visualization (ABV).  ABV is an innovative framework which lets structured data (from Oracle’s Agile PLM for instance) interact with unstructured data (documents, design, 3D models, etc). With this new level of integration, information coming from multiple sources can be presented in a highly visual fashion; color displays can be used in order to identify parts with specific characteristics (for example pending quality issues) and you can take actions directly from within the context of documents and designs, maximizing user productivity. Those who had the chance to attend our PLM session during Oracle Open World already got a sneak peek of our latest augmented business visualization for Oracle’s Agile PLM. The solution generated a lot of wows. Stephen Porter, CEO at Zero Wait State, indicated in a post entitled “The PLM State: the Manhattan Project-Oracle’s Next Big Secret Weapon” that “this kind of synergy between visualization and PLM could qualify as a powerful weapon differentiating Agile PLM from other solutions.” If you are interested in learning more about ABV for Oracle’s Agile PLM and hear about real examples of usage of visualization at all stages of the visualization maturity curve, don’t miss our Visual Decision Making to Optimize New Product Development and Introduction session during the Oracle Value Chain Summit (Feb. 4-6, 2013, San Francisco). We look forward to seeing you there!

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  • A Facelift for Fusion

    - by Richard Lefebvre
    It's simple. It's modern. It was the buzz at OpenWorld in San Francisco. See what the UX team has been up to and what customers are going to love. At OpenWorld 2012, the Oracle Applications User Experience (UX) team unveiled the new face of Fusion Applications. You might have seen it in sessions presented by Chris Leone, Anthony Lye, Jeremy Ashley and others or you may have gotten a look on the demogrounds. Why are we delivering a new face for Fusion Applications? "Because," says Ashley, vice president of the Oracle Applications User Experience team, "we want to provide a simple, modern, productive way for users to complete their top quick-entry tasks. The idea is to provide a clear, productive user experience that is backed by the full functionality of Fusion Applications." The first release of the new face of Fusion focuses on three types of users. It provides a fully functional gateway to Fusion Applications for: ·         New and casual users who need quick access to self-service tasks ·         Professional users who need fast access to quick-entry, high-volume tasks ·         Users who are looking for a way to quickly brand their portal for employees The new face of Fusion allows users to move easily from navigation to action, Ashley said, and it has been designed for any device -- Mac, PC, iPad, Android, SmartBoard -- in the browser. How Did We Build It? The new face of Fusion essentially is a custom shell, developed by the Apps UX team, and a set of page templates that embodies a simple design aesthetic. It's repeatable, providing consistency across its pages, and the need for training is little to zero. More specifically, the new face of Fusion has been built on ADF. The Applications UX team created pages in JDeveloper using local tasks flows bound to existing view objects. Three new components were commissioned from ADF and existing Fusion components were re-skinned to deliver a simple, modern user experience. It really is that simple - and to prove that point, we've been sharing our new face of Fusion story on several Oracle channels such as this one. If you want to learn more, check OpenWorld presentation on the Fusion Learning Center.

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  • Should UTF-16 be considered harmful?

    - by Artyom
    I'm going to ask what is probably quite a controversial question: "Should one of the most popular encodings, UTF-16, be considered harmful?" Why do I ask this question? How many programmers are aware of the fact that UTF-16 is actually a variable length encoding? By this I mean that there are code points that, represented as surrogate pairs, take more than one element. I know; lots of applications, frameworks and APIs use UTF-16, such as Java's String, C#'s String, Win32 APIs, Qt GUI libraries, the ICU Unicode library, etc. However, with all of that, there are lots of basic bugs in the processing of characters out of BMP (characters that should be encoded using two UTF-16 elements). For example, try to edit one of these characters: 𝄞 (U+1D11E) MUSICAL SYMBOL G CLEF 𝕥 (U+1D565) MATHEMATICAL DOUBLE-STRUCK SMALL T 𝟶 (U+1D7F6) MATHEMATICAL MONOSPACE DIGIT ZERO 𠂊 (U+2008A) Han Character You may miss some, depending on what fonts you have installed. These characters are all outside of the BMP (Basic Multilingual Plane). If you cannot see these characters, you can also try looking at them in the Unicode Character reference. For example, try to create file names in Windows that include these characters; try to delete these characters with a "backspace" to see how they behave in different applications that use UTF-16. I did some tests and the results are quite bad: Opera has problem with editing them (delete required 2 presses on backspace) Notepad can't deal with them correctly (delete required 2 presses on backspace) File names editing in Window dialogs in broken (delete required 2 presses on backspace) All QT3 applications can't deal with them - show two empty squares instead of one symbol. Python encodes such characters incorrectly when used directly u'X'!=unicode('X','utf-16') on some platforms when X in character outside of BMP. Python 2.5 unicodedata fails to get properties on such characters when python compiled with UTF-16 Unicode strings. StackOverflow seems to remove these characters from the text if edited directly in as Unicode characters (these characters are shown using HTML Unicode escapes). WinForms TextBox may generate invalid string when limited with MaxLength. It seems that such bugs are extremely easy to find in many applications that use UTF-16. So... Do you think that UTF-16 should be considered harmful?

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  • ArchBeat Link-o-Rama for 2012-09-05

    - by Bob Rhubart
    OTN Architect Day - Boston - Sept 12: What to Expect If you've never attended an OTN Architect Day, here's a little preview. You start with a continental breakfast. Then you have keynotes by an Oracle expert, and a member of the Oracle ACE community. After that come the break-out sessions, so you have your choice of two sessions in each time slot. So you'll get in two breakouts before lunch. Then you eat. After that there's a panel Q&A during which the audience tosses questions at the assembled session speakers. Then it's on to another set of break-out sessions, followed by a short break. Then the audience breaks into small groups for round table discussions. After that there's a drawing for some cool prizes, followed by the cocktail reception. All that costs you absolutely zero. Register now. Starting and Stopping Fusion Applications the Right Way | Ronaldo Viscuso While the fastartstop tool that ships with Oracle Fusion Applications does most of the work to start/stop/bounce the Fusion Apps environment, it does not do it all. Oracle Fusion Applications A-Team blogger Ronaldo Viscuso's post "aims to explain all tasks involved in starting and stopping a Fusion Apps environment completely." Dodeca Customer Feedback - The Rosewood Company | Tim Tow Oracle ACE Director Tim Tow shares anecdotal comments from one of his clients, a company that is deploying Dodeca to replace an aging VBA/Essbase application. Configuring UCM cache to check for external Content Server changes | Martin Deh Oracle WebCenter and ADF A-Team blogger Martin Deh shares the background information and the solution to a recently encountered customer scenario. Proxy As Upgrade to 11g Does Not Like NQSession.User | Art of Business Intelligence "In Oracle BI 10g the application was a lot more tolerant of bad design and cavalier usage of variables," observes Oracle ACE Christian Screen. "We noticed an issue recently during an upgrade where the Proxy As configuration in Oracle BI 10g used the NQSession.User variable to identify the user logged into Presentation Servers acting as Proxy." Oracle WebLogic Server 11g: Interactive Quick Reference | Dirk Nachbar Oracle ACE Dirk Nachbar shares a quick post with information on a new interactive reference guide to Oracle WebLogic Server. "The Quick Reference shows you an architecural overview of the Oracle WebLogic Server processes, tools, configuration files, log files and so on including a short description of each section and the corresponding link to the Oracle WebLogic Server Documentation," says Nachbar. Thought for the Day "In fast moving markets, adaptation is significantly more important than optimization." — Larry Constantine Source: Quotes for Software Engineers

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