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  • Role of an entity state in a component based system?

    - by Paul
    Component-based entity systems are all the rage these days; everyone seems to agree they are the way to go, but no one really has a definitive implementation of such a system. I was wondering, what role do entity states (walking-left, standing, jumping, etc) have in a CBS? Do they act like controllers (i.e. they handle events and change the entity's attributes based on those events)? What about cases where a state would, for example, require that the entity enters no-clip mode? Should, that state, when it enters, maybe set the CollisionComponent of the entity to a null pointer or something? (Then, on exit, the state should restore the entity's CollisionComponent to its previous state.) Also, I guess it's the current state's job to change the entity's state to something else, right?

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  • Relative cam movement and momentum on arbitrary surface

    - by user29244
    I have been working on a game for quite long, think sonic classic physics in 3D or tony hawk psx, with unity3D. However I'm stuck at the most fundamental aspect of movement. The requirement is that I need to move the character in mario 64 fashion (or sonic adventure) aka relative cam input: the camera's forward direction always point input forward the screen, left or right input point toward left or right of the screen. when input are resting, the camera direction is independent from the character direction and the camera can orbit the character when input are pressed the character rotate itself until his direction align with the direction the input is pointing at. It's super easy to do as long your movement are parallel to the global horizontal (or any world axis). However when you try to do this on arbitrary surface (think moving along complex curved surface) with the character sticking to the surface normal (basically moving on wall and ceiling freely), it seems harder. What I want is to achieve the same finesse of movement than in mario but on arbitrary angled surfaces. There is more problem (jumping and transitioning back to the real world alignment and then back on a surface while keeping momentum) but so far I didn't even take off the basics. So far I have accomplish moving along the curved surface and the relative cam input, but for some reason direction fail all the time (point number 3, the character align slowly to the input direction). Do you have an idea how to achieve that? Here is the code and some demo so far: The demo: https://dl.dropbox.com/u/24530447/flash%20build/litesonicengine/LiteSonicEngine5.html Camera code: using UnityEngine; using System.Collections; public class CameraDrive : MonoBehaviour { public GameObject targetObject; public Transform camPivot, camTarget, camRoot, relcamdirDebug; float rot = 0; //---------------------------------------------------------------------------------------------------------- void Start() { this.transform.position = targetObject.transform.position; this.transform.rotation = targetObject.transform.rotation; } void FixedUpdate() { //the pivot system camRoot.position = targetObject.transform.position; //input on pivot orientation rot = 0; float mouse_x = Input.GetAxisRaw( "camera_analog_X" ); // rot = rot + ( 0.1f * Time.deltaTime * mouse_x ); // wrapAngle( rot ); // //when the target object rotate, it rotate too, this should not happen UpdateOrientation(this.transform.forward,targetObject.transform.up); camRoot.transform.RotateAround(camRoot.transform.up,rot); //debug the relcam dir RelativeCamDirection() ; //this camera this.transform.position = camPivot.position; //set the camera to the pivot this.transform.LookAt( camTarget.position ); // } //---------------------------------------------------------------------------------------------------------- public float wrapAngle ( float Degree ) { while (Degree < 0.0f) { Degree = Degree + 360.0f; } while (Degree >= 360.0f) { Degree = Degree - 360.0f; } return Degree; } private void UpdateOrientation( Vector3 forward_vector, Vector3 ground_normal ) { Vector3 projected_forward_to_normal_surface = forward_vector - ( Vector3.Dot( forward_vector, ground_normal ) ) * ground_normal; camRoot.transform.rotation = Quaternion.LookRotation( projected_forward_to_normal_surface, ground_normal ); } float GetOffsetAngle( float targetAngle, float DestAngle ) { return ((targetAngle - DestAngle + 180)% 360) - 180; } //---------------------------------------------------------------------------------------------------------- void OnDrawGizmos() { Gizmos.DrawCube( camPivot.transform.position, new Vector3(1,1,1) ); Gizmos.DrawCube( camTarget.transform.position, new Vector3(1,5,1) ); Gizmos.DrawCube( camRoot.transform.position, new Vector3(1,1,1) ); } void OnGUI() { GUI.Label(new Rect(0,80,1000,20*10), "targetObject.transform.up : " + targetObject.transform.up.ToString()); GUI.Label(new Rect(0,100,1000,20*10), "target euler : " + targetObject.transform.eulerAngles.y.ToString()); GUI.Label(new Rect(0,100,1000,20*10), "rot : " + rot.ToString()); } //---------------------------------------------------------------------------------------------------------- void RelativeCamDirection() { float input_vertical_movement = Input.GetAxisRaw( "Vertical" ), input_horizontal_movement = Input.GetAxisRaw( "Horizontal" ); Vector3 relative_forward = Vector3.forward, relative_right = Vector3.right, relative_direction = ( relative_forward * input_vertical_movement ) + ( relative_right * input_horizontal_movement ) ; MovementController MC = targetObject.GetComponent<MovementController>(); MC.motion = relative_direction.normalized * MC.acceleration * Time.fixedDeltaTime; MC.motion = this.transform.TransformDirection( MC.motion ); //MC.transform.Rotate(Vector3.up, input_horizontal_movement * 10f * Time.fixedDeltaTime); } } Mouvement code: using UnityEngine; using System.Collections; public class MovementController : MonoBehaviour { public float deadZoneValue = 0.1f, angle, acceleration = 50.0f; public Vector3 motion ; //-------------------------------------------------------------------------------------------- void OnGUI() { GUILayout.Label( "transform.rotation : " + transform.rotation ); GUILayout.Label( "transform.position : " + transform.position ); GUILayout.Label( "angle : " + angle ); } void FixedUpdate () { Ray ground_check_ray = new Ray( gameObject.transform.position, -gameObject.transform.up ); RaycastHit raycast_result; Rigidbody rigid_body = gameObject.rigidbody; if ( Physics.Raycast( ground_check_ray, out raycast_result ) ) { Vector3 next_position; //UpdateOrientation( gameObject.transform.forward, raycast_result.normal ); UpdateOrientation( gameObject.transform.forward, raycast_result.normal ); next_position = GetNextPosition( raycast_result.point ); rigid_body.MovePosition( next_position ); } } //-------------------------------------------------------------------------------------------- private void UpdateOrientation( Vector3 forward_vector, Vector3 ground_normal ) { Vector3 projected_forward_to_normal_surface = forward_vector - ( Vector3.Dot( forward_vector, ground_normal ) ) * ground_normal; transform.rotation = Quaternion.LookRotation( projected_forward_to_normal_surface, ground_normal ); } private Vector3 GetNextPosition( Vector3 current_ground_position ) { Vector3 next_position; // //-------------------------------------------------------------------- // angle = 0; // Vector3 dir = this.transform.InverseTransformDirection(motion); // angle = Vector3.Angle(Vector3.forward, dir);// * 1f * Time.fixedDeltaTime; // // if(angle > 0) this.transform.Rotate(0,angle,0); // //-------------------------------------------------------------------- next_position = current_ground_position + gameObject.transform.up * 0.5f + motion ; return next_position; } } Some observation: I have the correct input, I have the correct translation in the camera direction ... but whenever I attempt to slowly lerp the direction of the character in direction of the input, all I get is wild spin! Sad Also discovered that strafing to the right (immediately at the beginning without moving forward) has major singularity trapping on the equator!! I'm totally lost and crush (I have already done a much more featured version which fail at the same aspect)

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  • How do I stop stretching during window re-size in XNA?

    - by Bradley Uffner
    In my windowed mode XNA game when the user resizes the window the game stops updating the window and the last frame drawn is stretched and distorted until the user releases the mouse and the resize completes. Is there any way to have the game continue to run "normally", updating frames and redrawing the screen, during the resize event? I realize that keeping the render loop going while resizing may not be possible or recommended due do hardware managed resources getting continually created and destroyed, but is there any way to stop the ugly stretching? Ideally by leaving the existing frame unscaled in the top left, or with a black screen if that isn't possible.

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  • How can I map the docky anchor button so that it will launch the unity dash?

    - by user76179
    Example of a Docky Dock I have the Docky dock on my desktop. It has an anchor logo button (as seen on the left side image of the link above) that brings up the Docky settings. I want to map it so that it opens my dash instead. I believe I can do this through gconf and by setting the docky button to either my super key or the necessary path required to open the dash function (but I do not know this path or how to code a button to a keyboard key). How can I map the docky anchor button so that it will launch the unity dash (as similar to when you simply tap the super key)?

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  • Is there a preferred way to set up a virtual Ubuntu server on a desktop?

    - by Keith Groben
    I love Ubuntu, and as I am searching the internet, I am finding that some questions I have have not been answered yet. One of them is if there is a preferred way to set up a virtual server. I look through the Ubuntu Software Center, but found nothing from the search "Virtual Server" I then searched the internet and found lots of posts to trouble-shoot VMWare virtual servers. So, like a good researcher I looked in the Software center for VMWare. Sure enough I found "user agent" and "view open client". I didn't get sufficient info from the software center. And searching the website only left me scratching my head. I want to install Ubuntu Server Edition. I already have a server, but am cautious "trying out" things on it. So a virtual server sounds like what I need.

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  • adding executable file to path and launching from terminal directly

    - by ubunnttuu
    i just downloaded sublime text for my ubuntu, and its working fine. i have the executable file in my ~/sublime folder. now i would like to invoke this app from the terminal by just typing sublime. i suppose that is possible, pls let me know how. also, since this application did not need any configure/make/install (i just had to extract it and then use the exec file to run the app), i cannot add this to my gnome launcher fav apps panel. how can i put the app shortcut there, so that when i do a top-left and then type sublime, the results will show the applicaion and then i can click on it and invoke the app from there? thanks!

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  • Scrolling Box2D DebugDraw

    - by onedayitwillmake
    I'm developing a game using Box2D (javascript implementation - Box2DWeb), and I would like to know how I can pan the debug draw. I know the usual answer is - don't use debug draw, it's just for debugging. I'm not, however not all my objects are on the same screen, and i'd like to see where they are in the physics representation. How can I pan the debug drawing? As you can see the debug draw stuff, is show on the top left, but it only shows a small part of the world. Here is an example of what I mean: http://onedayitwillmake.com/ChuClone/ The game is open source, If you'd like to poke through and note something that perhaps i'm doing something that is obviously wrong: https://github.com/onedayitwillmake/ChuClone Here's my hacky way that I'm using now to scroll the b2DebugDraw view, in which I added a property offsetX and offsetY into b2DebugDraw

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  • Moving AI in a multiplayer game

    - by Smallbro
    I've been programming a multiplayer game and its coming together very nicely. It uses both TCP and UDP (UDP for movement and TCP for just about everything else). What I was wondering was how I would go about sending multiple moving AI without much lag. At first I used TCP for everything and it was very slow when people moved. I'm currently using a butchered version of this http://corvstudios.com/tutorials/udpMultiplayer.php for my movement system and I'm wondering what the best method of sending AI movements is. By movements I mean the AI chooses left/right/up/down and the player can see this happening. Thanks.

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  • Ubuntu 12.04 freezes on suspend hp folio 13

    - by Tom O'Brien
    I have ubuntu 12.04 running from a usb HDD on my hp folio 13. Everything is working, but at first the screen would only blacken when i closed the lid and didn't suspend. So, I followed this guide: https://github.com/deliciousrobots/ubuntu-hp-folio-13 after that, it sort of worked, but very unreliably. Now suspend doesn't even work and it always freeze. Usually the screen will turn black but I can still see my mouse. Sometimes my desktop background will show but the launcher wont be there or anything. Once I didn't have the menu bar on any windows or the top of the screen but the windows I had left open were still (sort of) responsive. Whats wrong? Help Thanks

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  • After executing a command in the terminal, I sometimes can't execute another

    - by jreed121
    First off sorry for the noob question, I'm sure it's been asked before but I have no idea how to phrase it eloquently... Sometimes when I open/run/execute (unsure of proper term) an application (?lol) from the terminal like geany ie: geany filename.php or maybe run a node.js script: node server.js The command will execute fine, but I'm then left without the ability to execute any other commands unless I open another terminal. my root@pcname:~$ is gone and when I try typing in something else and hitting Enter it just breaks to the next line. I've noticed that sometimes I can hit CTRL+D and it'll give me my prompt back (sorry is prompt even the right name for it?) So could someone please explain why this is happening and how I can get back to the prompt without opening another terminal. Thanks, and sorry again for my noobery.

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  • projected textures not appear on the "back" of the mesh as well?

    - by user975135
    I want to create blood wounds on my character's bodies by using projected textures. I've watched some commentaries on games like Left 4 Dead and they say they use projected textures for the blood. But the way projected textures work is that if you project a texture on a rigged character, say his chest, it will also appear on his back. So what's the trick? How to get projected textures appear only on one "side" of the mesh? I use the Panda3D game engine, if that will help.

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  • about ubuntu upgrade for version 11.02

    - by Mr Myo MIn Hein
    In my Ubuntu version, I cannot get the essence of Ubuntu because my version is low. Most of the software cannot be used and some command are not really working. My 300GB HDD is not found. My primary HDD is 750GB, and has Windows 7 and Ubuntu on it in dual-boot. On Windows, a 450GB HDD for storage is found. The next question is about my launcher. It is not on the left side, so I cannot use it efficiently because it is in one third of my desktop.

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  • Integrating Azure ServiceBus and SharePoint 2010

    - by Sahil Malik
    SharePoint 2010 Training: more information My new article is finally online. I had been waiting for this for a while. The thing is, AppFabric became .NET 4, and left SharePoint 2010 behind. But fear not, we have REST API. But that brings up interesting challenges of how we can integrate Azure Service Bus with SharePoint 2010 (yes 2010, not vNext – I’m not giving NDA information out you fool), the design patterns you can use, figuring out challenging issues like security, sessions, and just app design patterns instead. Well, I hope you like my next article, SharePoint Applied: Azure ServiceBus and SharePoint 2010 Enjoy! Read full article ....

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  • How to copy a part of a link in google chrome?

    - by Mikhail Morfikov
    Is there a way to copy a part of text of a link which is located on a website in google chrome browser? For instance: If we see a link on a website, and we hover mouse on it, we can click on it, but we can also highlight it if we press left mouse button and drag mouse pointer starting from either the beginning or the end of the link. But what if we have a link -- http://sourceforge.net/ , and we want to copy only the word "forge"? Remember that this is not the same as copying from the address bar in google chrome browser.

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  • Ubuntu 14.04 Notification incorrectly displayed

    - by xenolyse
    I have a problem with my notifications on Ubuntu 14.04 x64. The notifications are just plain text with a colored background, and are also strangely placed in the top left corner. I have no idea on how it changed. After one reboot it was just there.. Here is a picture of the problem in question.: As you can see the notification appear over the unified menu. How can I restore the original state of the notification bubble? Here are the settings in ~/.notify-osd slot-allocation = fixed bubble-expire-timeout = 10sec bubble-vertical-gap = 5px bubble-horizontal-gap = 5px bubble-corner-radius = 37,5% bubble-icon-size = 30px bubble-gauge-size = 6px bubble-width = 240px bubble-background-color = 131313 bubble-background-opacity = 90% text-margin-size = 10px text-title-size = 100% text-title-weight = bold text-title-color = ffffff text-title-opacity = 100% text-body-size = 90% text-body-weight = normal text-body-color = eaeaea text-body-opacity = 100% text-shadow-opacity = 100% If I check the org.freedesktop.Notifications.service(/usr/share/dbus-1/servies) it appears to use the correct one. [D-BUS Service] Name=org.freedesktop.Notifications Exec=/usr/lib/x86_64-linux-gnu/notify-osd

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  • Where do I get the source code to customize Unity?

    - by Muhammad Khan
    So one of the main reasons I migrated to Ubuntu 12.04 from Windows 7 was to be able to have more control over my system due to the flexibility and customizability of a Linux operating system. However, with Ubuntu I do not feel as if I am as in control as I can be. What I mean to say is, where are the source codes and everything for all of this that I can edit on my machine. For example, suppose I want to position my dock on the left to be on the right without wanting to install any new software. I simply want to see the GUI files and reposition it myself. How can I do that, if that's even possible? Thank You!

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  • Pixel perfect collision with paths (Android)

    - by keysersoze
    Hi I'm writing a game and I'm trying to do some pixel perfect collisions with paths. The player's character has a bitmask which looks for example like this: Currenly my code that handles player's collision with path looks like this: private boolean isTerrainCollisionDetected() { if(collisionRegion.op(player.getBounds(), terrain.getBottomPathBounds(), Region.Op.INTERSECT) || collisionRegion.op(player.getBounds(), terrain.getTopPathBounds(), Region.Op.INTERSECT)) { collisionRegion.getBounds(collisionRect); for(int i = collisionRect.left; i < collisionRect.right; i++) { for(int j = collisionRect.top; j < collisionRect.bottom; j++) { if(player.getBitmask().getPixel(i - player.getX(), j - player.getY()) != Color.TRANSPARENT) { return true; } } } } return false; } The problem is that collisions aren't pixel perfect. It detects collisions in situations like this: The question is: what can I do to improve my collision detection?

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  • Why does my model render differently than its preview?

    - by Raven Dreamer
    I've been importing .fbx files that I made with 3DS Max 2012 into Unity, and it's quite neat to see my models running around in game. However, I can't help but notice that the models, as they're rendered in game, vary substantially from what they look like in the preview (and also what they looked like in 3DS Max). Observe: In-Game Unity Preview 3DS Max My gut tells me that I'm not setting up Unity's lighting system properly. What, then, do I need to do, to either my scene or my model, in order to get the left-most picture to look like the middle one?

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  • Using disqus for a website (question on SERP and backlink)

    - by Homunculus Reticulli
    I am building a website and am trying to decide between writing my own commenting system and using disquss. One of the main deciding factors is that (obviously), I want comments left on my page to be show on SERPS. However, I remeber reading somewhere that disqus loads comments into a page using AJAX - and therefore the comments are "invisible" as far as Googlebot and other SE crawlers are concerned. Could someone confirm or refute this? The other question I have is about whether (as a commenter), When I place a comment on another website using disqus (including any links I may add to my comment), do the lionks in my comment count as a backlink (in other words are they "dofollow" or "nofollow" links)?

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  • Can not get to login screen, background starts with terminal prompt only

    - by Doug
    my uncle has Ubuntu on his work PC. Basically I came in to work today, and he had lost his UNITY side bar. I told him start with just rebooting it. He rebooted it... now it does not even get to the login screen. It gets to the background with the word UBUNTU, and the 6 or 7 dots, does it's little loading dot thing... then stops, and a black terminal opens on the top left with the background still in place. Personally, I think he screwed it up himself. He always swears he didn't touch anything, but I know better... Either way, I can't get him back into the desktop to even see if the sidebar is back. He's always screwing around pressing the wrong buttons on the login screen, hitting admin things and such... Any ideas?

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  • Is the "App" side of Windows 8 practical for programmers?

    - by jt0dd
    I like the tablet-friendliness of Windows 8 Apps, and some of the programming apps seem pretty neat, but there are many aspects that make me think I would have difficulty using this format for an efficient programming environment: Unlike the desktop + multiple windows setup, I can't simply drag my files around from source, to FTP or SFTP file managers, between folders, web applications, and into other apps, etc. I can't switch between apps as fast. This could have different implications with different monitor setups, but it seems like a shaky setup for an agile workflow. The split screen functionality is cool, but it doesn't seem to allow for as much maneuverability as the classic desktop setup. This could just require me getting used to the top-left corner shortcut, but it does bother me that I have to move my mouse all the way up there to see my different windows. These aspects could become relevant in the event that Windows were to move further towards their "app" structure and less towards the Windows 7 style. I'm wondering if anyone has been able to utilize the "App" side of Windows 8 for an efficient programming workflow.

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  • How to open the console in different browsers?

    - by Šime Vidas
    Chrome: Press CTRL + SHIFT + I to open the Developer Tools. Click on the "Open console." icon in the bottom left corner. IE9: Press F12 to open the developer tools. Open the Script tab, click the "Console" button on the right. Firefox 4: Press CTRL + SHIFT + K to open the Web console. What about Opera 11 and Safari 5? Clarification: By console I mean the JavaScript console that lets you input and execute JavaScript code.

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  • How to Tweak the Low Battery Action On Your Windows 7 Laptop

    - by The Geek
    If you’ve got a netbook with really great battery life, you’ll probably still have loads of time left even with only 10% of the battery remaining. Here’s how to tweak the settings so it alerts you or goes into sleep mode at a more reasonable time. Note: obviously if you don’t have a great battery in your laptop, you should probably be careful with these settings or you might lose data. If anything, you’d be better off making the notifications happen sooner in that case Latest Features How-To Geek ETC The 20 Best How-To Geek Linux Articles of 2010 The 50 Best How-To Geek Windows Articles of 2010 The 20 Best How-To Geek Explainer Topics for 2010 How to Disable Caps Lock Key in Windows 7 or Vista How to Use the Avira Rescue CD to Clean Your Infected PC The Complete List of iPad Tips, Tricks, and Tutorials Classic Super Mario Brothers Theme for Chrome and Iron Experimental Firefox Builds Put Tabs on the Title Bar (Available for Download) Android Trojan Found in the Wild Chaos, Panic, and Disorder Wallpaper Enjoy Christmas Beyond the Holiday with Christmas Eve Crisis Parrotfish Extends the Number of Services Accessible in Twitter Previews

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  • Ubuntu 12.04 desktop crash [closed]

    - by David Mannock
    12.04 is stable under a light load, but not under intensive use of Gaussian 09 vB1. Looks like a heating issue, but psensor says that all is well on 32-cores @56C. Similar results for 64 cores. Machine shuts down after 2-3h. Syslog shows shut down. Whoopsie crash reporter sends in report. After 259 updates on the weekend, I am left wondering what the heck is wrong with this release? My answer would be "EVERYTHING!". Can someone help me do some systematic checks on this OS and hardware.

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  • .NET Code Evolution

    - by Alois Kraus
    Originally posted on: http://geekswithblogs.net/akraus1/archive/2013/07/24/153504.aspxAt my day job I do look at a lot of code written by other people. Most of the code is quite good and some is even a masterpiece. And there is also code which makes you think WTF… oh it was written by me. Hm not so bad after all. There are many excuses reasons for bad code. Most often it is time pressure followed by not enough ambition (who cares) or insufficient training. Normally I do care about code quality quite a lot which makes me a (perceived) slow worker who does write many tests and refines the code quite a lot because of the design deficiencies. Most of the deficiencies I do find by putting my design under stress while checking for invariants. It does also help a lot to step into the code with a debugger (sometimes also Windbg). I do this much more often when my tests are red. That way I do get a much better understanding what my code really does and not what I think it should be doing. This time I do want to show you how code can evolve over the years with different .NET Framework versions. Once there was  time where .NET 1.1 was new and many C++ programmers did switch over to get rid of not initialized pointers and memory leaks. There were also nice new data structures available such as the Hashtable which is fast lookup table with O(1) time complexity. All was good and much code was written since then. At 2005 a new version of the .NET Framework did arrive which did bring many new things like generics and new data structures. The “old” fashioned way of Hashtable were coming to an end and everyone used the new Dictionary<xx,xx> type instead which was type safe and faster because the object to type conversion (aka boxing) was no longer necessary. I think 95% of all Hashtables and dictionaries use string as key. Often it is convenient to ignore casing to make it easy to look up values which the user did enter. An often followed route is to convert the string to upper case before putting it into the Hashtable. Hashtable Table = new Hashtable(); void Add(string key, string value) { Table.Add(key.ToUpper(), value); } This is valid and working code but it has problems. First we can pass to the Hashtable a custom IEqualityComparer to do the string matching case insensitive. Second we can switch over to the now also old Dictionary type to become a little faster and we can keep the the original keys (not upper cased) in the dictionary. Dictionary<string, string> DictTable = new Dictionary<string, string>(StringComparer.OrdinalIgnoreCase); void AddDict(string key, string value) { DictTable.Add(key, value); } Many people do not user the other ctors of Dictionary because they do shy away from the overhead of writing their own comparer. They do not know that .NET has for strings already predefined comparers at hand which you can directly use. Today in the many core area we do use threads all over the place. Sometimes things break in subtle ways but most of the time it is sufficient to place a lock around the offender. Threading has become so mainstream that it may sound weird that in the year 2000 some guy got a huge incentive for the idea to reduce the time to process calibration data from 12 hours to 6 hours by using two threads on a dual core machine. Threading does make it easy to become faster at the expense of correctness. Correct and scalable multithreading can be arbitrarily hard to achieve depending on the problem you are trying to solve. Lets suppose we want to process millions of items with two threads and count the processed items processed by all threads. A typical beginners code might look like this: int Counter; void IJustLearnedToUseThreads() { var t1 = new Thread(ThreadWorkMethod); t1.Start(); var t2 = new Thread(ThreadWorkMethod); t2.Start(); t1.Join(); t2.Join(); if (Counter != 2 * Increments) throw new Exception("Hmm " + Counter + " != " + 2 * Increments); } const int Increments = 10 * 1000 * 1000; void ThreadWorkMethod() { for (int i = 0; i < Increments; i++) { Counter++; } } It does throw an exception with the message e.g. “Hmm 10.222.287 != 20.000.000” and does never finish. The code does fail because the assumption that Counter++ is an atomic operation is wrong. The ++ operator is just a shortcut for Counter = Counter + 1 This does involve reading the counter from a memory location into the CPU, incrementing value on the CPU and writing the new value back to the memory location. When we do look at the generated assembly code we will see only inc dword ptr [ecx+10h] which is only one instruction. Yes it is one instruction but it is not atomic. All modern CPUs have several layers of caches (L1,L2,L3) which try to hide the fact how slow actual main memory accesses are. Since cache is just another word for redundant copy it can happen that one CPU does read a value from main memory into the cache, modifies it and write it back to the main memory. The problem is that at least the L1 cache is not shared between CPUs so it can happen that one CPU does make changes to values which did change in meantime in the main memory. From the exception you can see we did increment the value 20 million times but half of the changes were lost because we did overwrite the already changed value from the other thread. This is a very common case and people do learn to protect their  data with proper locking.   void Intermediate() { var time = Stopwatch.StartNew(); Action acc = ThreadWorkMethod_Intermediate; var ar1 = acc.BeginInvoke(null, null); var ar2 = acc.BeginInvoke(null, null); ar1.AsyncWaitHandle.WaitOne(); ar2.AsyncWaitHandle.WaitOne(); if (Counter != 2 * Increments) throw new Exception(String.Format("Hmm {0:N0} != {1:N0}", Counter, 2 * Increments)); Console.WriteLine("Intermediate did take: {0:F1}s", time.Elapsed.TotalSeconds); } void ThreadWorkMethod_Intermediate() { for (int i = 0; i < Increments; i++) { lock (this) { Counter++; } } } This is better and does use the .NET Threadpool to get rid of manual thread management. It does give the expected result but it can result in deadlocks because you do lock on this. This is in general a bad idea since it can lead to deadlocks when other threads use your class instance as lock object. It is therefore recommended to create a private object as lock object to ensure that nobody else can lock your lock object. When you read more about threading you will read about lock free algorithms. They are nice and can improve performance quite a lot but you need to pay close attention to the CLR memory model. It does make quite weak guarantees in general but it can still work because your CPU architecture does give you more invariants than the CLR memory model. For a simple counter there is an easy lock free alternative present with the Interlocked class in .NET. As a general rule you should not try to write lock free algos since most likely you will fail to get it right on all CPU architectures. void Experienced() { var time = Stopwatch.StartNew(); Task t1 = Task.Factory.StartNew(ThreadWorkMethod_Experienced); Task t2 = Task.Factory.StartNew(ThreadWorkMethod_Experienced); t1.Wait(); t2.Wait(); if (Counter != 2 * Increments) throw new Exception(String.Format("Hmm {0:N0} != {1:N0}", Counter, 2 * Increments)); Console.WriteLine("Experienced did take: {0:F1}s", time.Elapsed.TotalSeconds); } void ThreadWorkMethod_Experienced() { for (int i = 0; i < Increments; i++) { Interlocked.Increment(ref Counter); } } Since time does move forward we do not use threads explicitly anymore but the much nicer Task abstraction which was introduced with .NET 4 at 2010. It is educational to look at the generated assembly code. The Interlocked.Increment method must be called which does wondrous things right? Lets see: lock inc dword ptr [eax] The first thing to note that there is no method call at all. Why? Because the JIT compiler does know very well about CPU intrinsic functions. Atomic operations which do lock the memory bus to prevent other processors to read stale values are such things. Second: This is the same increment call prefixed with a lock instruction. The only reason for the existence of the Interlocked class is that the JIT compiler can compile it to the matching CPU intrinsic functions which can not only increment by one but can also do an add, exchange and a combined compare and exchange operation. But be warned that the correct usage of its methods can be tricky. If you try to be clever and look a the generated IL code and try to reason about its efficiency you will fail. Only the generated machine code counts. Is this the best code we can write? Perhaps. It is nice and clean. But can we make it any faster? Lets see how good we are doing currently. Level Time in s IJustLearnedToUseThreads Flawed Code Intermediate 1,5 (lock) Experienced 0,3 (Interlocked.Increment) Master 0,1 (1,0 for int[2]) That lock free thing is really a nice thing. But if you read more about CPU cache, cache coherency, false sharing you can do even better. int[] Counters = new int[12]; // Cache line size is 64 bytes on my machine with an 8 way associative cache try for yourself e.g. 64 on more modern CPUs void Master() { var time = Stopwatch.StartNew(); Task t1 = Task.Factory.StartNew(ThreadWorkMethod_Master, 0); Task t2 = Task.Factory.StartNew(ThreadWorkMethod_Master, Counters.Length - 1); t1.Wait(); t2.Wait(); Counter = Counters[0] + Counters[Counters.Length - 1]; if (Counter != 2 * Increments) throw new Exception(String.Format("Hmm {0:N0} != {1:N0}", Counter, 2 * Increments)); Console.WriteLine("Master did take: {0:F1}s", time.Elapsed.TotalSeconds); } void ThreadWorkMethod_Master(object number) { int index = (int) number; for (int i = 0; i < Increments; i++) { Counters[index]++; } } The key insight here is to use for each core its own value. But if you simply use simply an integer array of two items, one for each core and add the items at the end you will be much slower than the lock free version (factor 3). Each CPU core has its own cache line size which is something in the range of 16-256 bytes. When you do access a value from one location the CPU does not only fetch one value from main memory but a complete cache line (e.g. 16 bytes). This means that you do not pay for the next 15 bytes when you access them. This can lead to dramatic performance improvements and non obvious code which is faster although it does have many more memory reads than another algorithm. So what have we done here? We have started with correct code but it was lacking knowledge how to use the .NET Base Class Libraries optimally. Then we did try to get fancy and used threads for the first time and failed. Our next try was better but it still had non obvious issues (lock object exposed to the outside). Knowledge has increased further and we have found a lock free version of our counter which is a nice and clean way which is a perfectly valid solution. The last example is only here to show you how you can get most out of threading by paying close attention to your used data structures and CPU cache coherency. Although we are working in a virtual execution environment in a high level language with automatic memory management it does pay off to know the details down to the assembly level. Only if you continue to learn and to dig deeper you can come up with solutions no one else was even considering. I have studied particle physics which does help at the digging deeper part. Have you ever tried to solve Quantum Chromodynamics equations? Compared to that the rest must be easy ;-). Although I am no longer working in the Science field I take pride in discovering non obvious things. This can be a very hard to find bug or a new way to restructure data to make something 10 times faster. Now I need to get some sleep ….

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