Search Results

Search found 31319 results on 1253 pages for 'source engine'.

Page 132/1253 | < Previous Page | 128 129 130 131 132 133 134 135 136 137 138 139  | Next Page >

  • 7 Steps to Search Engine Optimization

    Internet Marketing is a new media and latest trend to advertising which moving away from conventional advertising like print media, electronic media and etc. Internet marketing is a holistic and effective approach on internet to reach wider and more defined target marketing.

    Read the article

  • Search Engine Optimization For Beginners

    Learning about the SEO techniques can be scary and a bit overwhelming to say the least. If you do not know anything about SEO now is the time to learn, before trying to do it with just a little bit of knowledge, you will fail if you do it that way.

    Read the article

  • Why You Shouldn't Pay For Search Engine Optimisation

    There are countless "service" providers out there who'll encourage you to part with substantial amounts of your cash with promises of soaring rankings and greatly increased traffic but the truth is that nobody can guarantee results. The main reason for this is that the people at Google are constantly ahead of the game. At any given time all that anyone has to work with is a snapshot of what the Google team was doing a number of months ago.

    Read the article

  • Search Engine Optimization

    The best way a company can inform its public about itself is through its website. Most corporations and firms today have a website to their name. The internet has proved itself to be an open market for all kinds of products; the only problem being the trouble of attracting internet users.

    Read the article

  • Search Engine Optimisation - How Much Should You Pay?

    Interested in SEO? Scared by just how much it can cost? Well, you can get great SEO without breaking the bank and the return on even small investments can be stellar. If you want to know how much is a reasonable price then this article attempts to lift the veil on SEO prices and ensure you, the consumer, get a great product at a reasonable and affordable price.

    Read the article

  • tipfy for Google App Engine: Is it stable? Can auth/session components of tipfy be used with webapp?

    - by cv12
    I am building a web application on Google App Engine that requires users to register with the application and subsequently authenticate with it and maintain sessions. I don't want to force users to have Google accounts. Also, the target audience for the application is the average non-geek, so I'm not very keen on using OpenID or OAuth. I need something simple like: User registers with an e-mail and password, and then can log back in with those credentials. I understand that this approach does not provide the security benefits of Google or OpenID authentication, but I am prepared to trade foolproof security for end-user convenience and hassle-free experience. I explored Django, but decided that consecutive deprecations from appengine-helper to app-engine-patch to django-nonrel may signal that path may be a bit risky in the long-term. I'd like to use a code base that is likely to be maintained consistently. I also explored standalone session/auth packages like gaeutilities and suas. GAEUtilities looked a bit immature (e.g., the code wasn't pythonic in places, in my opinion) and SUAS did not give me a lot of comfort with the cookie-only sessions. I could be wrong with my assessment of these two, so I would appreciate input on those (or others that may serve my objective). Finally, I recently came across tipfy. It appears to be based on Werkzeug and Alex Martelli spoke highly of it here on stackoverflow. I have two primary questions related to tipfy: As a framework, is it as mature as webapp? Is it stable and likely to be maintained for some time? Since my primary interest is the auth/session components, can those components of the tipfy framework be used with webapp, independent of the broader tipfy framework? If yes, I would appreciate a few pointers to how I could go about doing that.

    Read the article

  • Using CookieJar in Python to log in to a website from "Google App Engine". What's wrong here?

    - by brilliant
    Hello everybody, I've been trying to find a python code that would log in to my mail box on yahoo.com from "Google App Engine" . Here (click here to see that page) I was given this code: import urllib, urllib2, cookielib url = "https://login.yahoo.com/config/login?" form_data = {'login' : 'my-login-here', 'passwd' : 'my-password-here'} jar = cookielib.CookieJar() opener = urllib2.build_opener(urllib2.HTTPCookieProcessor(jar)) form_data = urllib.urlencode(form_data) # data returned from this pages contains redirection resp = opener.open(url, form_data) # yahoo redirects to http://my.yahoo.com, so lets go there instead resp = opener.open('http://mail.yahoo.com') print resp.read() The author of this script looked into HTML script of yahoo log-in form and came up with this script. That log-in form contains two fields, one for users' Yahoo! ID and another one is for users' password. Here is how HTML code of that page for both of those fields looks like: User ID field: <input type="text" maxlength="96" class="yreg_ipt" size="17" value="" id="username" name="login"> Password field: <input type="password" maxlength="64" class="yreg_ipt" size="17" value="" id="passwd" name="passwd"> However, when I uploaded this code to Google App Engine I discovered that this log-in form keeps coming back to me, which, I assume, means that logging-in process didn't succeed. Why is it so?

    Read the article

  • Using CookieJar in Python to log in to a website from "Google App Engine". What's wrong here?

    - by brilliant
    Hello everybody, I've been trying to find a python code that would log in to my mail box on yahoo.com from "Google App Engine" . Here (click here to see that page) I was given this code: import urllib, urllib2, cookielib url = "https://login.yahoo.com/config/login?" form_data = {'login' : 'my-login-here', 'passwd' : 'my-password-here'} jar = cookielib.CookieJar() opener = urllib2.build_opener(urllib2.HTTPCookieProcessor(jar)) form_data = urllib.urlencode(form_data) # data returned from this pages contains redirection resp = opener.open(url, form_data) # yahoo redirects to http://my.yahoo.com, so lets go there instead resp = opener.open('http://mail.yahoo.com') print resp.read() The author of this script looked into HTML script of yahoo log-in form and came up with this script. That log-in form contains two fields, one for users' Yahoo! ID and another one is for users' password. Here is how HTML code of that page for both of those fields looks like: User ID field: <input type="text" maxlength="96" class="yreg_ipt" size="17" value="" id="username" name="login"> Password field: <input type="password" maxlength="64" class="yreg_ipt" size="17" value="" id="passwd" name="passwd"> However, when I uploaded this code to Google App Engine I discovered that this log-in form keeps coming back to me, which, I assume, means that logging-in process didn't succeed. Why is it so?

    Read the article

  • Flex Drag & Drop: Detecting when all data has been moved from source to destination

    - by Adam Tuttle
    I have two mx:TileList controls that I'm using to allow editing of objects in batch. The first contains a collection of all available data, and the 2nd contains the current batch. Both are bound to ArrayCollections, and using the native drag-n-drop functionality of the TileList control the data is moved from one ArrayCollection to the other when an object is dragged between them. I need to change the currentState to show & reset the batch manipulation controls when the batch count goes from 0 to n or n to 0 items. Based on the documentation, I would have thought that I should listen to the dragComplete event, but my testing shows that instead of firing after the data has been removed from the source ArrayCollection and added to the destination ArrayCollection, it fires (consistently) between these two actions. Both lists are similar to this: <mx:TileList id="srcList" dragEnabled="true" dropEnabled="true" dragMoveEnabled="true" dataProvider="{images}" dragComplete="handleDragComplete(event)" allowMultipleSelection="true" /> And here's the source of the handleDragComplete function: private function handleDragComplete(e:DragEvent):void{ trace(e.dragInitiator.name + '.dragComplete: batch.length=' + batch.length.toString()); trace(e.dragInitiator.name + '.dragComplete: images.length=' + images.length.toString()); if (batch.length > 0){ currentState = 'show'; }else{ currentState = ''; } } And lastly, here's some example output from running the code. These are all run one after the other. Case 1: The application loads with 10 objects in the first list and the batch is empty. I dragged 1 object from the source list to the batch list. srcList.dragComplete: batch.length=1 srcList.dragComplete: images.length=10 (Expected: 1,9) Clearly, the object has been added to the batch ArrayCollection but not removed from the source. Case 2: Now, I'll drag a 2nd object into the batch. srcList.dragComplete: batch.length=2 srcList.dragComplete: images.length=9 (Expected: 2,8) Firstly, we can see that images.length has changed, showing that the object that I dragged from the source list to the batch list was removed AFTER the dragComplete event fired. The same thing happens this time: The new object is added to the batch ArrayCollection (batch.length=2), the dragComplete event fires (running these traces), and then the object is removed from the source ArrayCollection. Case 3: Now, I'll drag both images from the batch list back to their original location in the source list. batchList.dragComplete: batch.length=2 batchList.dragComplete: images.length=10 (Expected: 0,10) We can see that batch.length hasn't gone down, but the source images array is back at its original length of 10. QUESTION: Am I doing something wrong? Is there another event I could listen for? (Note: I tried both DragExit and DragDrop, just to be sure, and those behave as expected, but are not what I need.) Or is there another way to get the data that I want? Or... have I found a bug in the SDK?

    Read the article

  • build-helper-maven-plugin add-source does not working when trying to add linked resources

    - by Julian
    I am new to maven and hit a problem that looks easy in the first place but I already kept me busy for a whole day about and no way to get it working. First as part of running eclipse:eclipse plugin I create a linked folder like below: <linkedResources> <linkedResource> <name>properties</name> <type>2</type> <location>${PARENT-2-PROJECT_LOC}/some_other_project/properties</location> </linkedResource> <linkedResource> <name>properties/messages.properties</name> <type>1</type> <location>${PARENT-2-PROJECT_LOC}/some_other_project/properties/messages.properties</location> </linkedResource> And then I am adding that folder as a source folder like below: <plugin> <groupId>org.codehaus.mojo</groupId> <artifactId>build-helper-maven-plugin</artifactId> <version>1.7</version> <executions> <execution> <id>add-source</id> <phase>generate-sources</phase> <goals> <goal>add-source</goal> </goals> <configuration> <sources> <source>properties</source> <source>some_real_folder</source> </sources> </configuration> </execution> </executions> </plugin> However when I am looking at the generated .classpath in eclipse the “some_real_folder” is there but the “properties” is not. It looks like by default the build-helper-maven-plugin will check if the folder is there and if it is not it won’t add it. I am using maven 3.0.4 outside eclipse to run the build and I can see in the maven logs something like this: [INFO] Source directory: <some path>\properties added. This is my project structure: project1 \-- properties (this is the real folder) project2 \-- some_real_folder \-- properties (this is the link resource pointing to the project1/properties folder) All I need is to have both "some_real_folder" and the linked resource "properties" added to the .classpath of the project2

    Read the article

  • Endless terrain in jMonkey using TerrainGrid fails to render

    - by nightcrawler23
    I have started to learn game development using jMonkey engine. I am able to create single tile of terrain using TerrainQuad but as the next step I'm stuck at making it infinite. I have gone through the wiki and want to use the TerrainGrid class but my code does not seem to work. I have looked around on the web and searched other forums but cannot find any other code example to help. I believe in the below code, ImageTileLoader returns an image which is the heightmap for that tile. I have modified it to return the same image every time. But all I see is a black window. The Namer method is not even called. terrain = new TerrainGrid("terrain", patchSize, 513, new ImageTileLoader(assetManager, new Namer() { public String getName(int x, int y) { //return "Scenes/TerrainMountains/terrain_" + x + "_" + y + ".png"; System.out.println("X = " + x + ", Y = " + y); return "Textures/heightmap.png"; } })); These are my sources: jMonkeyEngine 3 Tutorial (10) - Hello Terrain TerrainGridTest.java ImageTileLoader This is the result when i use TerrainQuad: , My full code: // Sample 10 - How to create fast-rendering terrains from heightmaps, and how to // use texture splatting to make the terrain look good. public class HelloTerrain extends SimpleApplication { private TerrainQuad terrain; Material mat_terrain; private float grassScale = 64; private float dirtScale = 32; private float rockScale = 64; public static void main(String[] args) { HelloTerrain app = new HelloTerrain(); app.start(); } private FractalSum base; private PerturbFilter perturb; private OptimizedErode therm; private SmoothFilter smooth; private IterativeFilter iterate; @Override public void simpleInitApp() { flyCam.setMoveSpeed(200); initMaterial(); AbstractHeightMap heightmap = null; Texture heightMapImage = assetManager.loadTexture("Textures/heightmap.png"); heightmap = new ImageBasedHeightMap(heightMapImage.getImage()); heightmap.load(); int patchSize = 65; //terrain = new TerrainQuad("my terrain", patchSize, 513, heightmap.getHeightMap()); // * This Works but below doesnt work* terrain = new TerrainGrid("terrain", patchSize, 513, new ImageTileLoader(assetManager, new Namer() { public String getName(int x, int y) { //return "Scenes/TerrainMountains/terrain_" + x + "_" + y + ".png"; System.out.println("X = " + x + ", Y = " + y); return "Textures/heightmap.png"; // set to return the sme hieghtmap image. } })); terrain.setMaterial(mat_terrain); terrain.setLocalTranslation(0,-100, 0); terrain.setLocalScale(2f, 1f, 2f); rootNode.attachChild(terrain); TerrainLodControl control = new TerrainLodControl(terrain, getCamera()); terrain.addControl(control); } public void initMaterial() { // TERRAIN TEXTURE material this.mat_terrain = new Material(this.assetManager, "Common/MatDefs/Terrain/HeightBasedTerrain.j3md"); // GRASS texture Texture grass = this.assetManager.loadTexture("Textures/white.png"); grass.setWrap(WrapMode.Repeat); this.mat_terrain.setTexture("region1ColorMap", grass); this.mat_terrain.setVector3("region1", new Vector3f(-10, 0, this.grassScale)); // DIRT texture Texture dirt = this.assetManager.loadTexture("Textures/white.png"); dirt.setWrap(WrapMode.Repeat); this.mat_terrain.setTexture("region2ColorMap", dirt); this.mat_terrain.setVector3("region2", new Vector3f(0, 900, this.dirtScale)); Texture building = this.assetManager.loadTexture("Textures/building.png"); building.setWrap(WrapMode.Repeat); this.mat_terrain.setTexture("slopeColorMap", building); this.mat_terrain.setFloat("slopeTileFactor", 32); this.mat_terrain.setFloat("terrainSize", 513); } }

    Read the article

  • Adding Blog to Your Orchard Website

    - by hajan
    One of the common features in today’s content management systems is to provide you the ability to create your own blog in your website. Also, having a blog is one of the very often needed features for various types of websites. Out of the box, Orchard gives you this, so you can create your own blog in your Orchard website on a pretty easy way. Besides the fact that you can very easily create your own blog, Orchard also gives you some extra features in relation with the support of blogging, such as connecting third-party client applications (e.g. Windows Live Writer) to your blog, so that you can publish blog posts remotely. You can already find all the information provided in this blog post on the http://orchardproject.net website, however I thought it would be nice to make summary in one blog post. I assume you have already installed Orchard and you are already familiar with its environment and administration dashboard. If you haven’t, please read this blog post first.   CREATE YOUR BLOG First of all, go to Orchard Administration Dashboard and click on Blog in the left menu Once you are there, you will see the following screen   Fill the form with all needed data, as in the following example and click Save Right after, you should see the following screen Click New post, and add your first post. After that, go to Homepage (click Your Site in the top-left corner) and you should see the Blog link in your menu After clicking on Blog, you will be directed to the following page Once you click on My First Post, you will see that your blog already supports commenting ability (you can enable/disable this from Administration dashboard in your blog settings) Added comment Adding new comment Submit comment So, with following these steps, you have already setup your blog in your Orchard website.   CONNECT YOUR BLOG WITH WINDOWS LIVE WRITER Since many bloggers prepare their blog posts using third-party client applications, like Windows Live Writer, its very useful if your blog engine has the ability to work with these third-party applications and enable them to make remote posting and publishing. The client applications use XmlRpc interface in order to have the ability to manage and publish the blogs remotely. What is great about Orchard is that it gives you out of the box the XmlRpc and Remote Publishing modules. What you only need to do is to enable these features from the Modules in your Orchard Administration Dashboard. So, lets go through the steps of enabling and making your previously created blog able to work with third-party client applications for blogging. 1. Go to Administration Dashboard and click the Modules After clicking the Modules, you will see the following page: As you can see, you already have Remote Blog Publishing and XmlRpc features for Content Publishing, but both are disabled by default. So, if you click Enable only on Remote Blog Publishing, you will see both of them enabled at once since they are dependent features. After you click Enable, if everything is Ok, the following message should be displayed: So, now we have the featured enabled and ready... The next thing you need to do is to open Windows Live Writer. First, open Windows Live Writer and in your Blog Accounts, click on Add blog account In the next window, chose Other services After that, click on your Blog link in the Orchard website and copy the URL, my URL (on localhost development server) is: http://localhost:8191/blog Then, add your login credentials you use to login in Orchard and click Next. After that, if you have setup everything successfully, the Windows Live Writer will do the rest Once it finishes, you will have window where you can specify the name of your blog you have just connected your Windows Live Writer to... Then... you are done. You can see Windows Live Writer has detected the Orchard theme I am using After you finish with the blog post, click on Publish and refresh the Blog page in your Orchard website You see, we have the blog post directly posted from Windows Live Writer to my Orchard Blog. I hope this was useful blog post. Regards, Hajan Reference and other useful posts: Build incredible content-driven websites using Orchard CMS Create blog on your site with Orchard CMS Blogging using Windows Live Writer in your Orchard CMS Blog Orchard Website

    Read the article

  • Multiplayer / Networking options for a 2D game with physics

    - by lahmas
    Summary: My 50% finished 2D sidescroller with Box2D as physics engine should have multiplayer support in the final version. However, the current code is just a singleplayer game. What should I do now? And more important, how should I implement multiplayer and combine it with singleplayer? Is it a bad idea to code the singleplayer mode separated from multiplayer mode (like Notch did it with Minecraft)? The performance in singleplayer should be as good as possible (Simulating physics with using a loopback server to implement singleplayer mode would be a problem there) Full background / questions: I'm working on a relatively large 2D game project in C++, with physics as a core element of it. (I use Box2D for that) The finished game should have full multiplayer support, however I made the mistake that I didn't plan the networking part properly and basically worked on a singleplayer game until now. I thought that multiplayer support could be added to the almost finished singleplayer game in a relatively easy and clear way, but apparently, from what I have read this is wrong. I even read that a multiplayer game should be programmed as one from the beginning, with the singleplayer mode actually just consisting of hosting an invisible local server and connecting to it via loopback. (I found out that most FPS game engines do it that way, an example would be Source) So here I am, with my half finished 2D sidescroller game, and I don't really know how to go on. Simply continueing to work on the singleplayer / client seems useless to me now, as I'd have to recode and refactor even more later. First, a general question to anybody who possibly found himself in a situation like this: How should I proceed? Then, the more specific one - I have been trying to find out how I can approach the networking part for my game: (Possible solutions:) Invisible / loopback server for singleplayer This would have the advantage that there basically is no difference between singleplayer and multiplayer mode. Not much additional code would be needed. A big disadvantage: Performance and other limitations in singleplayer. There would be two physics simulations running. One for the client and one for the loopback server. Even if you work around by providing a direct path for the data from the loopback server, through direct communcation by the threads for example, the singleplayer would be limited. This is a problem because people should be allowed to play around with masses of objects at once. Separated singleplayer / Multiplayer mode There would be no server involved in singleplayer mode. I'm not really sure how this would work. But at least I think that there would be a lot of additional work, because all of the singleplayer features would have to be re-implemented or glued to multiplayer mode. Multiplayer mode as a module for singleplayer This is merely a quick thought I had. Multiplayer could consist of a singleplayer game, with an additional networking module loaded and connected to a server, which sends and receives data and updates the singleplayer world. In the retrospective, I regret not having planned the multiplayer mode earlier. I'm really stuck at this point and I hope that somebody here is able to help me!

    Read the article

  • Impressions on jQuery Mobile

    - by Jeff
    For the uninitiated, jQuery Mobile is a sweet little client framework that turns regular HTML into something more touch and mobile friendly. It results in a user interface that has bigger targets, rounded corners and simple skinning capability. When it was announced that ASP.NET MVC 4 would include support for a mobile-sensitive view engine, offering up alternate views for clients that fit the mobile profile, I was all over that. Combined with jQuery Mobile, it brought a chance to do some experimentation. I blitzed through the views in POP Forums and converted them all to mobile views. (For the curious, this first pass can be found here on CodePlex, while a more recent update that uses RC 2 of jQuery Mobile v1.1.0 is running on the demo site.) Initially, it was kind of a mixed bag. The jQuery demo site also acts as documentation, and it’s reasonably complete. I had no problem getting up a lot of basic views quickly, splitting out portions of some pages as subpages that they quickly load in. The default behavior in the older version was to slide the pages in, which looked a little weird when you were using a back button. They’ve since changed it so the default transition is a fade in/out. Because you’re dealing with Web pages, I don’t think anyone is really under the illusion that you’re not using a native app, so I don’t know that this matters. I’ve tested extensively on iPad and Windows Phone, and to be honest, I’ve encountered a lot of issues. On Windows Phone, there is some kind of inconsistency that prevents the proper respect for the viewport settings. The text background on text fields (for labeling) doesn’t work, either. On both platforms, certain in-DOM page navigation links work only half of the time. Is this an issue of user error? Probably, but that’s what’s frustrating about it. Most of what you accomplish with this framework involves decorating various elements with CSS classes. There isn’t any design-time safety to speak of to make sure that you’re doing it right. I think the issues can be overcome, but there are some trade-offs to consider. The first is download size. Yes, the scripts and CSS do get cached, but that first hit will cost nearly 40k for the mobile parts. That’s still a lot when you’re on some crappy AT&T EDGE network, or hotel Wi-Fi. Then you have to ask yourself, do you really want your app to look like it’s native to iOS? I’m not saying that’s a bad thing, because consistent UI is good, but you will end up feeling a whole lot of sameness, and maybe you don’t want that. I did some experimentation to try and Metro-ize the jQuery Mobile theme, and it’s kind of a mixed bag. It mostly works, but you get some weirdness on badges and with buttons that I’m not crazy about. It probably just means you need to keep tweaking. At this point, I’m a little torn about whether or not I’ll use it for POP Forums or one of the sites I’m working on. The benefits are pretty strong, but figuring out where I’m doing it wrong is proving a little time consuming.

    Read the article

  • Sharing on Github

    - by Alan
    Over the past couple weeks I have gotten a lot of help from StackOverflow users on a project, and rather than keep the finished product to myself I wanted to share it unencumbered by licenses, but don't want there to be so much legwork during installation that users shy away from trying it. I am about to post it to Github and choosing public domain licensing. I would like to to be super simple for users to make use of and just FTP it up and go. That being said, do I need to make sure I remove things like the JQuery file, and other GPL / MIT licensed dependencies that I didn't write but that my code depends on? I haven't removed any copyright notices from the other code and all of it open source, it would just be nice if users could download everything at once while of course not trying to represent that I am the license holder of the dependencies. Inside my files are also some snippets, do those have to be externalized with installation instructions or can it be posted as is? Here is an example, my nav.php file is 115 lines long and I have these at the top: <script type="text/javascript" src="./js/ddaccordion.js"> /*********************************************** * Accordion Content script- (c) Dynamic Drive DHTML code library (www.dynamicdrive.com) * Visit http://www.dynamicDrive.com for hundreds of DHTML scripts * This notice must stay intact for legal use ***********************************************/ </script> <link href="css/admin.css" rel="stylesheet"> <script type="text/javascript"> ddaccordion.init({ headerclass: "submenuheader", //Shared CSS class name of headers group contentclass: "submenu", //Shared CSS class name of contents group revealtype: "click", //Reveal content when user clicks or onmouseover the header? Valid value: "click", "clickgo", or "mouseover" mouseoverdelay: 200, //if revealtype="mouseover", set delay in milliseconds before header expands onMouseover collapseprev: false, //Collapse previous content (so only one open at any time)? true/false defaultexpanded: [], //index of content(s) open by default [index1, index2, etc] [] denotes no content onemustopen: false, //Specify whether at least one header should be open always (so never all headers closed) animatedefault: false, //Should contents open by default be animated into view? persiststate: true, //persist state of opened contents within browser session? toggleclass: ["", ""], //Two CSS classes to be applied to the header when it's collapsed and expanded, respectively ["class1", "class2"] togglehtml: ["suffix", "<img src='./images/plus.gif' class='statusicon' />", "<img src='./images/minus.gif' class='statusicon' />"], //Additional HTML added to the header when it's collapsed and expanded, respectively ["position", "html1", "html2"] (see docs) animatespeed: "fast", //speed of animation: integer in milliseconds (ie: 200), or keywords "fast", "normal", or "slow" oninit:function(headers, expandedindices){ //custom code to run when headers have initalized //do nothing }, onopenclose:function(header, index, state, isuseractivated){ //custom code to run whenever a header is opened or closed //do nothing } }) </script>

    Read the article

  • How to make a stack stable? Need help for an explicit resting contact scheme (2-dimensional)

    - by Register Sole
    Previously, I struggle with the sequential impulse-based method I developed. Thanks to jedediah referring me to this paper, I managed to rebuild the codes and implement the simultaneous impulse based method with Projected-Gauss-Seidel (PGS) iterative solver as described by Erin Catto (mentioned in the reference of the paper as [Catt05]). So here's how it currently is: The simulation handles 2-dimensional rotating convex polygons. Detection is using separating-axis test, with a SKIN, meaning closest points between two polygons is detected and determined if their distance is less than SKIN. To resolve collision, simultaneous impulse-based method is used. It is solved using iterative solver (PGS-solver) as in Erin Catto's paper. Error-correction is implemented using Baumgarte's stabilization (you can refer to either paper for this) using J V = beta/dt*overlap, J is the Jacobian for the constraints, V the matrix containing the velocities of the bodies, beta an error-correction parameter that is better be < 1, dt the time-step taken by the engine, and overlap, the overlap between the bodies (true overlap, so SKIN is ignored). However, it is still less stable than I expected :s I tried to stack hexagons (or squares, doesn't really matter), and even with only 4 to 5 of them, they would swing! Also note that I am not looking for a sleeping scheme. But I would settle if you have any explicit scheme to handle resting contacts. That said, I would be more than happy if you have a way of treating it generally (as continuous collision, instead of explicitly as a special state). Ideas I have tried: Using simultaneous position based error correction as described in the paper in section 5.3.2, turned out to be worse than the current scheme. If you want to know the parameters I used: Hexagons, side 50 (pixels) gravity 2400 (pixels/sec^2) time-step 1/60 (sec) beta 0.1 restitution 0 to 0.2 coeff. of friction 0.2 PGS iteration 10 initial separation 10 (pixels) mass 1 (unit is irrelevant for now, i modified velocity directly<-impulse method) inertia 1/1000 Thanks in advance! I really appreciate any help from you guys!! :) EDIT In response to Cholesky's comment about warm starting the solver and Baumgarte: Oh right, I forgot to mention! I do save the contact history and the impulse determined in this time step to be used as initial guess in the next time step. As for the Baumgarte, here's what actually happens in the code. Collision is detected when the bodies' closest distance is less than SKIN, meaning they are actually still separated. If at this moment, I used the PGS solver without Baumgarte, restitution of 0 alone would be able to stop the bodies, separated by a distance of ~SKIN, in mid-air! So this isn't right, I want to have the bodies touching each other. So I turn on the Baumgarte, where its role is actually to pull the bodies together! Weird I know, a scheme intended to push the body apart becomes useful for the reverse. Also, I found that if I increase the number of iteration to 100, stacks become much more stable, though the program becomes so slow. UPDATE Since the stack swings left and right, could it be something is wrong with my friction model? Current friction constraint: relative_tangential_velocity = 0

    Read the article

< Previous Page | 128 129 130 131 132 133 134 135 136 137 138 139  | Next Page >