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  • What is a useful pattern to maintaining an object state in a one to many relationship?

    - by ahenderson
    I am looking for a design for my application, here are the players(classes) involved. struct Transform { // Uses a matrix to transform the position. // Also acts acts as the state of a Dialog. Position transform(Position p); //other methods. }; struct Dialog { // There are multiple dialog for the user to transform the output. Transform& t; void ChangeTranformation(){t.rotate(360);} } struct Algorithm { //gives us a position based on an implementation. For example this can return points on a circle or line. Transform& t; Position m_p; Dialog& d; Position GetCurrentPosition(){ return t.transform(m_p);} //other methods. } Properties I need: Each algorithms has one dialog and each dialog can have many algorithms associated with it. When the user selects an algorithm a dialog associated with that algorithm is displayed. If the user selects a different algorithm then re-selects back the state is restored in the dialog. Basically I want a good design pattern to maintain the state of the dialog given that many algorithms use it and they can be switched back and forth. Does anyone have any suggestions? Here is a use case: Dialog1 has a single edit box to control the radius. Algorithm1 generates points on a unit circle. Algorithm2 is the same as Algorithm1. The user has selected Algorithm1 and entered 2 into the edit box. This will generate points on a circle of radius 2. The user then selects Algorithm2 and enters 10 into the edit box of Dialog1. This will generate points on a circle of radius 10. Finally Algorithm1 is selected again. The edit box of Dialog1 should show 2 and points on a circle of radius 2 should be generated.

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  • xna manual animation

    - by tasyjean
    i want to animate 3d model in xna programmatically ,i tried to transform bones but nothing to happen only the whole model transform not individual bones as i want i read the 3d model by basic model processor so how i do this ? and is there any need to extended model processor like skinnedModelSample please explain the steps

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  • How does Ruby's Enumerator object iterate externally over an internal iterator?

    - by Salman Paracha
    As per Ruby's documentation, the Enumerator object uses the each method (to enumerate) if no target method is provided to the to_enum or enum_for methods. Now, let's take the following monkey patch and its enumerator, as an example o = Object.new def o.each yield 1 yield 2 yield 3 end e = o.to_enum loop do puts e.next end Given that the Enumerator object uses the each method to answer when next is called, how do calls to the each method look like, every time next is called? Does the Enumeartor class pre-load all the contents of o.each and creates a local copy for enumeration? Or is there some sort of Ruby magic that hangs the operations at each yield statement until next is called on the enumeartor? If an internal copy is made, is it a deep copy? What about I/O objects that could be used for external enumeration? I'm using Ruby 1.9.2.

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  • How do I check if an instance has an object to skip displaying the values?

    - by Angela
    I have created a polymorphic association around a model called status. Some contacts will have a status associated with it. Many won't. If I try to call a status when one is not there, I get an error. Right now, even if I haven't created a status for the model, it still runs whatever is in the if-end block. Here's what I am trying, but it's not working: <% if [email protected]? %> <p>Status: <%= @status.find(:last).status %></p> <% end %> In the controller, it is defined below: @status = Contact.find(@contact).statuses By the way, also open to make code more readable and DRY.

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  • What's a good way to check that a player has clicked on an object in a 3D game?

    - by imja
    I'm programming a 3D game (using C++ and OpenGL), and I have a few 3D objects in the scene, we can say they are boxes for this example. I want to let the player click on those boxes to select them (ie. they might change color) with the typical restriction like if more than one box is located where the user clicked, only the one closest to the camera would get selected. What would be the best way to do this? The fact that these objects go through several transforms before getting to window coordinates is what makes this a bit tricky. One approach I thought about was that if the player clicks on the screen, I could normalize the x,y coordinates of mouse click and then transform the bounding box coordinates of the objects into clip-space so that I could compare then to the normalized mouse coordinates. I guess I could then do some sort of ray-box collision test to see if any objects lie as the path of the mouse click. I'm afraid I might be over complicating it. Any better methods out there?

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  • How would you structure your entity model for storing arbitrary key/value data with different data t

    - by Nathan Ridley
    I keep coming across scenarios where it will be useful to store a set of arbitrary data in a table using a per-row key/value model, rather than a rigid column/field model. The problem is, I want to store the values with their correct data type rather than converting everything to a string. This means I have to choose either a single table with multiple nullable columns, one for each data type, or a set of value tables, one for each data type. I'm also unsure as to whether I should use full third normal form and separate the keys into a separate table, referencing them via a foreign key from the value table(s), or if it would be better to keep things simple and store the string keys in the value table(s) and accept the duplication of strings. Old/bad: This solution makes adding additional values a pain in a fluid environment because the table needs to be modified regularly. MyTable ============================ ID Key1 Key2 Key3 int int string date ---------------------------- 1 Value1 Value2 Value3 2 Value4 Value5 Value6 Single Table Solution This solution allows simplicity via a single table. The querying code still needs to check for nulls to determine which data type the field is storing. A check constraint is probably also required to ensure only one of the value fields contains non-nulll data. DataValues ============================================================= ID RecordID Key IntValue StringValue DateValue int int string int string date ------------------------------------------------------------- 1 1 Key1 Value1 NULL NULL 2 1 Key2 NULL Value2 NULL 3 1 Key3 NULL NULL Value3 4 2 Key1 Value4 NULL NULL 5 2 Key2 NULL Value5 NULL 6 2 Key3 NULL NULL Value6 Multiple-Table Solution This solution allows for more concise purposing of each table, though the code needs to know the data type in advance as it needs to query a different table for each data type. Indexing is probably simpler and more efficient because there are less columns that need indexing. IntegerValues =============================== ID RecordID Key Value int int string int ------------------------------- 1 1 Key1 Value1 2 2 Key1 Value4 StringValues =============================== ID RecordID Key Value int int string string ------------------------------- 1 1 Key2 Value2 2 2 Key2 Value5 DateValues =============================== ID RecordID Key Value int int string date ------------------------------- 1 1 Key3 Value3 2 2 Key3 Value6 How do you approach this problem? Which solution is better? Also, should the key column be separated into a separate table and referenced via a foreign key or be should it be kept in the value table and bulk updated if for some reason the key name changes?

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  • How do I make all the finders on the model ignorecase?

    - by Glex
    I have a model with several attributes, among them title and artist. The case of title and artist should be ignored in all the Active Record finders. Basically, if title or artist are present in the :conditions (or dynamically i.e. find_all_by_artist), then the WHERE artist = :artist should become WHERE UPPER(artist) = UPPER(:artist) or something along these lines. Is there a way of doing it with Rails?

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  • In WPF, how do I update the object that my custom property is bound to?

    - by Timothy Khouri
    I have a custom property that works perfectly, except when it's bound to an object. The reason is that once the following code is executed: base.SetValue(ValueProperty, value); ... then my control is no longer bound. I know this because calling: base.GetBindingExpression(ValueProperty); ... returns the binding object perfectly - UNTIL I call base.SetValue. So my question is, how do I pass the new "value" on to the object that I'm bound to?

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  • Do unused vertices in a 3D object affect performance?

    - by Gajet
    For my game I need to generate a mesh dynamically. Now I'm wondering does it have a noticeable affect in FPS if I allocate more vertices than what I'm actually using or not? and does it matter if I'm using DirectX or OpenGL? Edit Final output will be a w*h cell grid, but for technical issues it's much easier for me to allocate (w+1)*(h+1) vertices. Sure I'll only use w*h vertices in indexing, and I know there is some memory wasting there, but I want to know if it also affect FPS or not? (Note that mesh is only generated once in each time you play the game)

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  • How to persist and load an object which conforms to NSCoding protocol?

    - by mystify
    I have made an class which conforms to the NSCoding protocol and does all the encode and decode stuff. For my app, I simply want to persist an object from that class to the device and the next time when the app launches, I want to load that object back into memory. Basically it's just an class which holds some user input information. For example the user starts writing a text but then quits the app. Next time I want to load that data object. I guess I need NSKeyedArchiver? Is there a good tutorial on this? How do I do that?

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  • Determining if something is on the right or left side of an object?

    - by meds
    I have a character in a 3D world which is facing an arbitrary direction on a flat plane, the player can click on the left or right side of the character and based on which side is clicked on a different action happens. How can I determine which side the click occured on? Obviously for straight on ahead (0,0,1) I can simply use the x coordinate of the click point to determine if it's the left or right hand side, but what about other cases?

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  • does unused vertices in a 3D object affect performance?

    - by Gajet
    For my game I need to generate a mesh dynamically. now I'm wondering does it have a noticeable affect in fps if I allocate more vertices than what I'm actually using or not? and does it matter if I'm using DirectX or OpenGL? edit final output will be a w*h cell grid, but for technical issues it's much more easier for me to allocate (w+1)*(h+1) vertices. sure I'll only use w*h vertices in indexing, and I know there is some memory wasting there, but I want to know if it also affect fps or not? (note that mesh is only generated once in each time you play the game)

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  • List in a Python class shares the same object over 2 different instances?

    - by zfranciscus
    I created a class: class A: aList = [] now I have function that instantiate this class and add items into the aList. note: there are 2 items for item in items: a = A(); a.aList.append(item); I find that the first A and the second A object has the same number of items in their aList. I would expect that the first A object will have the first item in its list and the second A object will have the second item in its aList. Can anyone explain how this happens ? PS: I manage to solve this problem by moving the aList inside a constructor : def __init__(self): self.aList = []; but I am still curious about this behavior

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  • nonatomic property in model class when using NSOperationQueue (iPhone)?

    - by Andrew B.
    I have a custom model class with an NSMutableData ivar that will be accessed by custom NSOperation subclasses (using an NSOperationQueue). I think I can guarantee thread-safe access to the ivar from multiple NSOperations by using dependencies, and I can guarantee that I don't access the ivar from other code (say my main app thread) by waiting until the Q has finished all operations. Should I use a nonatomic property specification, or leave it atomic? Is there a significant impact on performance?

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  • How do I find out if an object can be Invoke()'d?

    - by Jurily
    Consider the following class: public class Event<T> { public delegate void Handler<t>(t msg); private event Handler<T> E; public void connect(Delegate handler) { E += delegate(T msg) { object target = handler.Target; if (Invokable(target) { target.BeginInvoke(handler, new object[] { msg }); } }; } public void emit(T msg) { if ( E != null ) { E(msg); } } private static bool Invokable(object o) { // magic } } How do I implement Invokable(), and what else do I need for this code to compile?

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  • How can I check the type of an object against a list of types?

    - by RookieRick
    Given a collection IEnumerable<Type> supportedTypes What's the best way to check whether a given object is one of those types (or a derived type)? My first instinct was to do something like: // object target is a parameter passed to the method in which I'm doing this. if (supportedTypes.Count( supportedType => target is supportedType ) > 0) { // Yay my object is of a supported type!!! } ..but that doesn't seem to be working. Can I not use the "is" keyword in a lambda expression like this?

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  • Yii file upload issue

    - by user1289853
    Couple of months ago,I developed a simple app using YII,one of the feature was to upload file. The feature was working well in my dev machine,couple of days ago client found the file upload feature is not working in his server since deployment. And after that I test my dev machine that was not working too. My controller looks: public function actionEntry() { if (!Yii::app()->user->isGuest) { $model = new TrackForm; if (isset($_POST['TrackForm'])) { $entry = new Track; try { $entry->product_image = $_POST['TrackForm']['product_image']; $entry->product_image = CUploadedFile::getInstance($model, 'product_image'); if ($entry->save()) { if ($entry->product_image) { $entry->product_image->saveAs($entry->product_image->name, '/trackshirt/uploads'); } } $this->render('success', array('model' => $model)); // redirect to success page } } catch (Exception $e) { echo 'Caught exception: ', $e->getMessage(), "\n"; } } else { $this->render('entry', array('model' => $model)); } } } Model is like below: <?php class Track extends CActiveRecord { public static function model($className=__CLASS__) { return parent::model($className); } public function tableName() { return 'product_details'; } } My view looks: <?php $form = $this->beginWidget('CActiveForm', array( 'id' => 'hide-form', 'enableClientValidation' => true, 'clientOptions' => array( 'validateOnSubmit' => true, ), 'htmlOptions' => array('enctype' => 'multipart/form-data'), )); ?> <p class="auto-style2"><strong>Administration - Add New Product</strong></p> <table align="center" style="width: 650px"><td class="auto-style3" style="width: 250px">Product Image</td> <td> <?php echo $form->activeFileField($model, 'product_image'); ?> </td> </tr> </table> <p class="auto-style1"> <div style="margin-leftL:-100px;"> <?php echo CHtml::submitButton('Submit New Product Form'); ?> </div> <?php $this->endWidget(); ?> Any idea where is the problem?I tried to debug it but every time it returns Null. Thanks.

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  • Is there an difference between transient properties defined in the data model, or in the custom subc

    - by mystify
    I was reading that setting the value of a transient property always results in marking the managed object as "dirty". However, what I don't get is this: If I make a subclass of NSManagedObject and use some extra properties which I don't need to be persistet, how does Core Data know about them and how can it mark the object as dirty when I access these? Again, they're not defined in the data model, so Core Data has no really good hint that they are there. Or does Core Data use some kind of introspection to analyze my custom class and figure out what properties I have in there?

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  • How do you use a flash object as a link?

    - by Matthew Crumley
    Is it possible to use a flash document embedded in HTML as a link? I tried just wrapping the object element with an a like this: <a href="http://whatever.com"> <object ...> <embed ... /> </object> </a> In Internet Explorer, that made it show the location in the status bar like a link, but it doesn't do anything. I just have the .swf file, so I can't add a click handler in ActionScript.

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  • how to generate JMX MXBean compatible java class model from JAXB?

    - by yucubby
    From the JMX MXBean specification, a java class type J must satisfy Either if J has at least one public constructor with a ConstructorProperties annotation, Or if J has a public no-arg constructor, and for every getter in J with type T and name N there is a corresponding setter with the same name and type So how can I use JAXB to generate JAVA class model which satisfy the MXBean constrain? Thanks YU

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