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  • Points on lines where the two lines are the closest together

    - by James Bedford
    Hey guys, I'm trying to find the points on two lines where the two lines are the closest. I've implemented the following method (Points and Vectors are as you'd expect, and a Line consists of a Point on the line and a non-normalized direction Vector from that point): void CDClosestPointsOnTwoLines(Line line1, Line line2, Point* closestPoints) { closestPoints[0] = line1.pointOnLine; closestPoints[1] = line2.pointOnLine; Vector d1 = line1.direction; Vector d2 = line2.direction; float a = d1.dot(d1); float b = d1.dot(d2); float e = d2.dot(d2); float d = a*e - b*b; if (d != 0) // If the two lines are not parallel. { Vector r = Vector(line1.pointOnLine) - Vector(line2.pointOnLine); float c = d1.dot(r); float f = d2.dot(r); float s = (b*f - c*e) / d; float t = (a*f - b*c) / d; closestPoints[0] = line1.positionOnLine(s); closestPoints[1] = line2.positionOnLine(t); } else { printf("Lines were parallel.\n"); } } I'm using OpenGL to draw three lines that move around the world, the third of which should be the line that most closely connects the other two lines, the two end points of which are calculated using this function. The problem is that the first point of closestPoints after this function is called will lie on line1, but the second point won't lie on line2, let alone at the closest point on line2! I've checked over the function many times but I can't see where the mistake in my implementation is. I've checked my dot product function, scalar multiplication, subtraction, positionOnLine() etc. etc. So my assumption is that the problem is within this method implementation. If it helps to find the answer, this is function supposed to be an implementation of section 5.1.8 from 'Real-Time Collision Detection' by Christer Ericson. Many thanks for any help!

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  • What is Granularity?

    - by tonyrogerson
    Granularity defines “the lowest level of detail”; but what is meant by “the lowest level of detail”? Consider the Transactions table below: create table Transactions ( TransactionID int not null primary key clustered, TransactionDate date not null, ClientID int not null, StockID int not null, TransactionAmount decimal ( 28 , 2 ) not null, CommissionAmount decimal ( 28 , 5 ) not null ) A Client can Trade in one or many Stocks on any date – there is no uniqueness to ClientID, Stock and TransactionDate...(read more)

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  • How to sort a ListView control by a column in Visual C#

    - by bconlon
    Microsoft provide an article of the same name (previously published as Q319401) and it shows a nice class 'ListViewColumnSorter ' for sorting a standard ListView when the user clicks the column header. This is very useful for String values, however for Numeric or DateTime data it gives odd results. E.g. 100 would come before 99 in an ascending sort as the string compare sees 1 < 9. So my challenge was to allow other types to be sorted. This turned out to be fairly simple as I just needed to create an inner class in ListViewColumnSorter which extends the .Net CaseInsensitiveComparer class, and then use this as the ObjectCompare member's type. Note: Ideally we would be able to use IComparer as the member's type, but the Compare method is not virtual in CaseInsensitiveComparer , so we have to create an exact type: public class ListViewColumnSorter : IComparer {     private CaseInsensitiveComparer ObjectCompare;     private MyComparer ObjectCompare;     ... rest of Microsofts class implementation... } Here is my private inner comparer class, note the 'new int Compare' as Compare is not virtual, and also note we pass the values to the base compare as the correct type (e.g. Decimal, DateTime) so they compare correctly: private class MyComparer : CaseInsensitiveComparer {     public new int Compare(object x, object y)     {         try         {             string s1 = x.ToString();             string s2 = y.ToString();               // check for a numeric column             decimal n1, n2 = 0;             if (Decimal.TryParse(s1, out n1) && Decimal.TryParse(s2, out n2))                 return base.Compare(n1, n2);             else             {                 // check for a date column                 DateTime d1, d2;                 if (DateTime.TryParse(s1, out d1) && DateTime.TryParse(s2, out d2))                     return base.Compare(d1, d2);             }         }         catch (ArgumentException) { }           // just use base string compare         return base.Compare(x, y);     } } You could extend this for other types, even custom classes as long as they support ICompare. Microsoft also have another article How to: Sort a GridView Column When a Header Is Clicked that shows this for WPF, which looks conceptually very similar. I need to test it out to see if it handles non-string types. #

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  • Strange date relationships with #PowerPivot

    - by Marco Russo (SQLBI)
    A reader of my PowerPivot book highlighted a strange behavior of the relationship between a datetime column and a Calendar table. Long story short: it seems that PowerPivot automatically round the date to the “neareast day”, but instead of simply removing the time (truncating the decimal part of the decimal number internally used to represent a datetime value) a rounding function seems used, moving the date to the next day if the time part contain a PM time. As you can imagine, this becomes particularly...(read more)

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  • Characteristics, what's the inverse of (x*(x+1))/2? [closed]

    - by Valmond
    In my game you can spend points to upgrade characteristics. Each characteristic has a formula like: A) out = in : for one point spent, one pont gained (you spend 1 point on Force so your force goes from 5 to 6) B) out = last level (starting at 1) : so the first point spent earns you 1 point, the next point spent earns you an additional 2 and so on (+3,+4,+5...) C) The inverse of B) : You need to spend 1 point to earn one, then you need to spend 2 to earn another one and so on. I have already found the formula for calculating the actual level of B when points spent = x : charac = (x*(x+1))/2 But I'd like to know what the "reverse" version of B) (usable for C) is, ie. if I have spent x points, how many have I earned if 1 spent gives 1, 1+2=3 gives 2, 1+2+3=6 gives 3 and so on. I know I can just calculate the numbers but I'd like to have the formula because its neater and so that I can stick it in an excel sheet for example... Thanks! ps. I think I have nailed it down to something like charac = sqrt( x*m +k) but then I'm stuck doing number guessing for k and m and I feel I might be wrong anyway as I get close but never hits the spot.

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  • htaccess redirect *.domain.com to www.domain.com/index.php

    - by decimal
    I want to redirect a user to www.domain.com/index.php if they type in either: domain.com or www.domain.com. I'm clueless about htaccess. Here's what I found but I don't know how to write an OR statement for the www. redirect RewriteEngine on RewriteCond %{HTTP_HOST} ^domain\.com RewriteRule (.*) http://www.domain.com/index.php$1 [R=301]

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  • PHP contact form, am I doing it wrong?

    - by decimal
    I'm learning PHP and I'm trying to write a simple email script. I have a function (checkEmpty) to check if all the forms are filled in and if the email adress is valid (isEmailValid). I'm not sure how to return true checkEmpty funciton. Here's my code: When the submit button is clicked: if (isset($_POST['submit'])) { //INSERT FORM VALUES INTO AN ARRAY $field = array ('name' => $_POST['name'], 'email' => $_POST['email'], 'message' => $_POST['message']); //CONVERT ARRAY KEYS TO VARIABLE NAMES extract ($field); checkEmpty($name, $email, $message); function checkEmpty($name, $email, $message) { global $name_error; global $mail_error; global $message_error; //CHECK IF NAME FIELD IS EMPTY if (isset($name) === true && empty($name) === true) { $name_error = "<span class='error_text'>* Please enter your name</span>"; } //CHECK IF EMAIL IS EMPTY if (isset($email) === true && empty($email) === true) { $mail_error = "<span class='error_text'>* Please enter your email address</span>"; //AND IF IT ISN'T EMPTY CHECK IF IT IS A VALID ONE } elseif (!isValidEmail($email)) { $mail_error = "<span class='error_text'> * Please enter a valid email</span>"; } //CHECK IF MESSAGE IS EMPTY if (isset($message) === true && empty($message) === true) { $message_error = "<span class='error_text'>* Please enter your message</span>"; } } // This function tests whether the email address is valid function isValidEmail($email){ $pattern = "^[_a-z0-9-]+(\.[_a-z0-9-]+)*@[a-z0-9-]+(\.[a-z0-9-]+)*(\.[a-z]{2,3})$"; if (eregi($pattern, $email)) { return true; } else { return false; } } I know I shouldn't be using globals in the function, I don't know an alternative. The error messages are display beside each form element.

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  • Output custom messages based on row value

    - by decimal
    I've made a simple guestbook mysql/php page. An entry is displayed if the approve column has a value of 1. For the adminstrator, I want to display either "message approved" or "not approved". Here's my code: while ($row = mysql_fetch_array ($r)) { print "<p>Guest:" .$row['name']. "</p> <p>Date:" .$row['date']. "</p> <p>Comment:". $row['comment']. "</p>"; if ($row['approve'] = '1') { print '<p>YES, the message has been approved</p>'; } else { print '<p>NO, it hasn\'t been approved</p>'; } Whatever value the if statement checks approve is equal to, all approve values are output as that value.

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  • real time plotting on iPhone using core plot?

    - by ram007
    I want to use core-plot for drawing line graph dynamically. data won't come at a time, we will be receiving point by point dynamically. Is it possible to draw the chart dynamically using core-plot i.e drawing point by point as on when we receive the (x,y) point? Please help me, Thanks.

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  • UTF-8 and JTextArea

    - by ManWard
    hi i have 2 JTextArea that one of these contain Unicode Code point like this \u0645 i want another JTextArea show Character representation of this Unicode code point.but when pass this code point to JTextArea , it show code point not Character but if i set code point to JTextArea setText method directly it work correctly ! why ? and which can i pass String of Codepoint from one JTextArea to another ? thanks

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  • Animation using AniMate with Unity3D doesn't interact with physical objects

    - by Albz
    I'm designing a maze with Unity3D. The maze has a number of bifurcations and the player will stop before each bifurcation and simply choose left or right. Then an automatic animation will move the player through the next bifurcation till the end of the maze (or till a dead end). To animate the player I'm using AniMate and C# in my Unity project. Using AniMate I'm simply creating a point-to-point animation for each bifurcation (e.g. mage below: from the start/red arrow to point 5) My problem is that my animation script (associated to the "First Person Controller") is not working properly since physics is not respected (the player passes through walls). If in the same project I enable the standard character controls in Unity, then I can navigate in the maze with the physical contrains of walls etc... (i.e. I have colliders). This is an example of the code I'm using when I press left to pass from starting point, trough point 1 to point 2: void FixedUpdate () { if (Input.GetKey(KeyCode.LeftArrow)) { //To point 1 Hashtable props = new Hashtable(); props.Add("position", new Vector3(756f,112f,1124f)); props.Add("physics", true); Ani.Mate.To(transform, 2, props); //To point 2 Hashtable props2 = new Hashtable(); props2.Add("position", new Vector3(731f,112f,1124f)); props2.Add("physics", true); Ani.Mate.To(transform, 2, props2); } } What happens practically when I press the left arrow button is that the player moves directly to point 2 using a straight line passing through the wall. I tried to pass to AniMate "Physics = true" but it doesn't seem to help. Any idea on how to solve this issue? Alternatively... any hint on how to have a more optimized code and just use a series of vector3 coordinates (one for each point) to obtain the simple animation I want without having to declare new Hashtable(); etc... every time? I chose AniMate simply because 1. I'm a beginner with Unity 2. I don't need complex animations (e.g. I don't need to use iTween), just fixed animations along straight lines and I need something really simple and quick to implement in a script. However, if someone has an equally simple solution it will be welcome. thank you in advance for your help

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  • Issues with touch buttons in XNA (Release state to be precise)

    - by Aditya
    I am trying to make touch buttons in WP8 with all the states (Pressed, Released, Moved), but the TouchLocationState.Released is not working. Here's my code: Class variables: bool touching = false; int touchID; Button tempButton; Button is a separate class with a method to switch states when touched. The Update method contains the following code: TouchCollection touchCollection = TouchPanel.GetState(); if (!touching && touchCollection.Count > 0) { touching = true; foreach (TouchLocation location in touchCollection) { for (int i = 0; i < menuButtons.Count; i++) { touchID = location.Id; // store the ID of current touch Point touchLocation = new Point((int)location.Position.X, (int)location.Position.Y); // create a point Button button = menuButtons[i]; if (GetMenuEntryHitBounds(button).Contains(touchLocation)) // a method which returns a rectangle. { button.SwitchState(true); // change the button state tempButton = button; // store the pressed button for accessing later } } } } else if (touchCollection.Count == 0) // clears the state of all buttons if no touch is detected { touching = false; for (int i = 0; i < menuButtons.Count; i++) { Button button = menuButtons[i]; button.SwitchState(false); } } menuButtons is a list of buttons on the menu. A separate loop (within the Update method) after the touched variable is true if (touching) { TouchLocation location; TouchLocation prevLocation; if (touchCollection.FindById(touchID, out location)) { if (location.TryGetPreviousLocation(out prevLocation)) { Point point = new Point((int)location.Position.X, (int)location.Position.Y); if (prevLocation.State == TouchLocationState.Pressed && location.State == TouchLocationState.Released) { if (GetMenuEntryHitBounds(tempButton).Contains(point)) // Execute the button action. I removed the excess } } } } The code for switching the button state is working fine but the code where I want to trigger the action is not. location.State == TouchLocationState.Released mostly ends up being false. (Even after I release the touch, it has a value of TouchLocationState.Moved) And what is more irritating is that it sometimes works! I am really confused and stuck for days now. Is this the right way? If yes then where am I going wrong? Or is there some other more effective way to do this? PS: I also posted this question on stack overflow then realized this question is more appropriate in gamedev. Sorry if it counts as being redundant.

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  • Platformer Collision Error [closed]

    - by Connor
    I am currently working on a relatively simple platform game that has an odd bug.You start the game by falling onto the ground (you spawn a few blocks above the ground), but when you land your feet get stuck INSIDE the world and you can't move until you jump. Here's what I mean: The player's feet are a few pixels below the ground level. However, this problem only occurs in 3 places throughout the map and only in those 3 select places. I'm assuming that the problem lies within my collision detection code but I'm not entirely sure, as I don't get an error when it happens. public boolean isCollidingWithBlock(Point pt1, Point pt2) { //Checks x for(int x = (int) (this.x / Tile.tileSize); x < (int) (this.x / Tile.tileSize + 4); x++) { //Checks y for(int y = (int) (this.y / Tile.tileSize); y < (int) (this.y / Tile.tileSize + 4); y++) { if(x >= 0 && y >= 0 && x < Component.dungeon.block.length && y < Component.dungeon.block[0].length) { //If the block is not air if(Component.dungeon.block[x][y].id != Tile.air) { //If the player is in contact with point one or two on the block if(Component.dungeon.block[x][y].contains(pt1) || Component.dungeon.block[x][y].contains(pt2)) { //Checks for specific blocks if(Component.dungeon.block[x][y].id == Tile.portalBlock) { Component.isLevelDone = true; } if(Component.dungeon.block[x][y].id == Tile.spike) { Health.health -= 1; Component.isJumping = true; if(Health.health == 0) { Component.isDead = true; } } return true; } } } } } return false; } What I'm asking is how I would fix the problem. I've looked over my code for quite a while and I'm not sure what's wrong with it. Also, if there's a more efficient way to do my collision checking then please let me know! I hope that is enough information, if it's not just tell me what you need and I'll be sure to add it. Thank you! [EDIT] Jump code: if(!isJumping && !isCollidingWithBlock(new Point((int) x + 2, (int) (y + height)), new Point((int) (x + width + 2), (int) (y + height)))) { y += fallSpeed; //sY is the screen's Y. The game is a side-scroller Component.sY += fallSpeed; } else { if(Component.isJumping) { isJumping = true; } } if(isJumping) { if(!isCollidingWithBlock(new Point((int) x + 2, (int) y), new Point((int) (x + width + 2), (int) y))) { if(jumpCount >= jumpHeight) { isJumping = false; jumpCount = 0; } else { y -= jumpSpeed; Component.sY -= jumpSpeed; jumpCount += 1; } } else { isJumping = false; jumpCount = 0; } }

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  • The Incremental Architect&rsquo;s Napkin - #5 - Design functions for extensibility and readability

    - by Ralf Westphal
    Originally posted on: http://geekswithblogs.net/theArchitectsNapkin/archive/2014/08/24/the-incremental-architectrsquos-napkin---5---design-functions-for.aspx The functionality of programs is entered via Entry Points. So what we´re talking about when designing software is a bunch of functions handling the requests represented by and flowing in through those Entry Points. Designing software thus consists of at least three phases: Analyzing the requirements to find the Entry Points and their signatures Designing the functionality to be executed when those Entry Points get triggered Implementing the functionality according to the design aka coding I presume, you´re familiar with phase 1 in some way. And I guess you´re proficient in implementing functionality in some programming language. But in my experience developers in general are not experienced in going through an explicit phase 2. “Designing functionality? What´s that supposed to mean?” you might already have thought. Here´s my definition: To design functionality (or functional design for short) means thinking about… well, functions. You find a solution for what´s supposed to happen when an Entry Point gets triggered in terms of functions. A conceptual solution that is, because those functions only exist in your head (or on paper) during this phase. But you may have guess that, because it´s “design” not “coding”. And here is, what functional design is not: It´s not about logic. Logic is expressions (e.g. +, -, && etc.) and control statements (e.g. if, switch, for, while etc.). Also I consider calling external APIs as logic. It´s equally basic. It´s what code needs to do in order to deliver some functionality or quality. Logic is what´s doing that needs to be done by software. Transformations are either done through expressions or API-calls. And then there is alternative control flow depending on the result of some expression. Basically it´s just jumps in Assembler, sometimes to go forward (if, switch), sometimes to go backward (for, while, do). But calling your own function is not logic. It´s not necessary to produce any outcome. Functionality is not enhanced by adding functions (subroutine calls) to your code. Nor is quality increased by adding functions. No performance gain, no higher scalability etc. through functions. Functions are not relevant to functionality. Strange, isn´t it. What they are important for is security of investment. By introducing functions into our code we can become more productive (re-use) and can increase evolvability (higher unterstandability, easier to keep code consistent). That´s no small feat, however. Evolvable code can hardly be overestimated. That´s why to me functional design is so important. It´s at the core of software development. To sum this up: Functional design is on a level of abstraction above (!) logical design or algorithmic design. Functional design is only done until you get to a point where each function is so simple you are very confident you can easily code it. Functional design an logical design (which mostly is coding, but can also be done using pseudo code or flow charts) are complementary. Software needs both. If you start coding right away you end up in a tangled mess very quickly. Then you need back out through refactoring. Functional design on the other hand is bloodless without actual code. It´s just a theory with no experiments to prove it. But how to do functional design? An example of functional design Let´s assume a program to de-duplicate strings. The user enters a number of strings separated by commas, e.g. a, b, a, c, d, b, e, c, a. And the program is supposed to clear this list of all doubles, e.g. a, b, c, d, e. There is only one Entry Point to this program: the user triggers the de-duplication by starting the program with the string list on the command line C:\>deduplicate "a, b, a, c, d, b, e, c, a" a, b, c, d, e …or by clicking on a GUI button. This leads to the Entry Point function to get called. It´s the program´s main function in case of the batch version or a button click event handler in the GUI version. That´s the physical Entry Point so to speak. It´s inevitable. What then happens is a three step process: Transform the input data from the user into a request. Call the request handler. Transform the output of the request handler into a tangible result for the user. Or to phrase it a bit more generally: Accept input. Transform input into output. Present output. This does not mean any of these steps requires a lot of effort. Maybe it´s just one line of code to accomplish it. Nevertheless it´s a distinct step in doing the processing behind an Entry Point. Call it an aspect or a responsibility - and you will realize it most likely deserves a function of its own to satisfy the Single Responsibility Principle (SRP). Interestingly the above list of steps is already functional design. There is no logic, but nevertheless the solution is described - albeit on a higher level of abstraction than you might have done yourself. But it´s still on a meta-level. The application to the domain at hand is easy, though: Accept string list from command line De-duplicate Present de-duplicated strings on standard output And this concrete list of processing steps can easily be transformed into code:static void Main(string[] args) { var input = Accept_string_list(args); var output = Deduplicate(input); Present_deduplicated_string_list(output); } Instead of a big problem there are three much smaller problems now. If you think each of those is trivial to implement, then go for it. You can stop the functional design at this point. But maybe, just maybe, you´re not so sure how to go about with the de-duplication for example. Then just implement what´s easy right now, e.g.private static string Accept_string_list(string[] args) { return args[0]; } private static void Present_deduplicated_string_list( string[] output) { var line = string.Join(", ", output); Console.WriteLine(line); } Accept_string_list() contains logic in the form of an API-call. Present_deduplicated_string_list() contains logic in the form of an expression and an API-call. And then repeat the functional design for the remaining processing step. What´s left is the domain logic: de-duplicating a list of strings. How should that be done? Without any logic at our disposal during functional design you´re left with just functions. So which functions could make up the de-duplication? Here´s a suggestion: De-duplicate Parse the input string into a true list of strings. Register each string in a dictionary/map/set. That way duplicates get cast away. Transform the data structure into a list of unique strings. Processing step 2 obviously was the core of the solution. That´s where real creativity was needed. That´s the core of the domain. But now after this refinement the implementation of each step is easy again:private static string[] Parse_string_list(string input) { return input.Split(',') .Select(s => s.Trim()) .ToArray(); } private static Dictionary<string,object> Compile_unique_strings(string[] strings) { return strings.Aggregate( new Dictionary<string, object>(), (agg, s) => { agg[s] = null; return agg; }); } private static string[] Serialize_unique_strings( Dictionary<string,object> dict) { return dict.Keys.ToArray(); } With these three additional functions Main() now looks like this:static void Main(string[] args) { var input = Accept_string_list(args); var strings = Parse_string_list(input); var dict = Compile_unique_strings(strings); var output = Serialize_unique_strings(dict); Present_deduplicated_string_list(output); } I think that´s very understandable code: just read it from top to bottom and you know how the solution to the problem works. It´s a mirror image of the initial design: Accept string list from command line Parse the input string into a true list of strings. Register each string in a dictionary/map/set. That way duplicates get cast away. Transform the data structure into a list of unique strings. Present de-duplicated strings on standard output You can even re-generate the design by just looking at the code. Code and functional design thus are always in sync - if you follow some simple rules. But about that later. And as a bonus: all the functions making up the process are small - which means easy to understand, too. So much for an initial concrete example. Now it´s time for some theory. Because there is method to this madness ;-) The above has only scratched the surface. Introducing Flow Design Functional design starts with a given function, the Entry Point. Its goal is to describe the behavior of the program when the Entry Point is triggered using a process, not an algorithm. An algorithm consists of logic, a process on the other hand consists just of steps or stages. Each processing step transforms input into output or a side effect. Also it might access resources, e.g. a printer, a database, or just memory. Processing steps thus can rely on state of some sort. This is different from Functional Programming, where functions are supposed to not be stateful and not cause side effects.[1] In its simplest form a process can be written as a bullet point list of steps, e.g. Get data from user Output result to user Transform data Parse data Map result for output Such a compilation of steps - possibly on different levels of abstraction - often is the first artifact of functional design. It can be generated by a team in an initial design brainstorming. Next comes ordering the steps. What should happen first, what next etc.? Get data from user Parse data Transform data Map result for output Output result to user That´s great for a start into functional design. It´s better than starting to code right away on a given function using TDD. Please get me right: TDD is a valuable practice. But it can be unnecessarily hard if the scope of a functionn is too large. But how do you know beforehand without investing some thinking? And how to do this thinking in a systematic fashion? My recommendation: For any given function you´re supposed to implement first do a functional design. Then, once you´re confident you know the processing steps - which are pretty small - refine and code them using TDD. You´ll see that´s much, much easier - and leads to cleaner code right away. For more information on this approach I call “Informed TDD” read my book of the same title. Thinking before coding is smart. And writing down the solution as a bunch of functions possibly is the simplest thing you can do, I´d say. It´s more according to the KISS (Keep It Simple, Stupid) principle than returning constants or other trivial stuff TDD development often is started with. So far so good. A simple ordered list of processing steps will do to start with functional design. As shown in the above example such steps can easily be translated into functions. Moving from design to coding thus is simple. However, such a list does not scale. Processing is not always that simple to be captured in a list. And then the list is just text. Again. Like code. That means the design is lacking visuality. Textual representations need more parsing by your brain than visual representations. Plus they are limited in their “dimensionality”: text just has one dimension, it´s sequential. Alternatives and parallelism are hard to encode in text. In addition the functional design using numbered lists lacks data. It´s not visible what´s the input, output, and state of the processing steps. That´s why functional design should be done using a lightweight visual notation. No tool is necessary to draw such designs. Use pen and paper; a flipchart, a whiteboard, or even a napkin is sufficient. Visualizing processes The building block of the functional design notation is a functional unit. I mostly draw it like this: Something is done, it´s clear what goes in, it´s clear what comes out, and it´s clear what the processing step requires in terms of state or hardware. Whenever input flows into a functional unit it gets processed and output is produced and/or a side effect occurs. Flowing data is the driver of something happening. That´s why I call this approach to functional design Flow Design. It´s about data flow instead of control flow. Control flow like in algorithms is of no concern to functional design. Thinking about control flow simply is too low level. Once you start with control flow you easily get bogged down by tons of details. That´s what you want to avoid during design. Design is supposed to be quick, broad brush, abstract. It should give overview. But what about all the details? As Robert C. Martin rightly said: “Programming is abot detail”. Detail is a matter of code. Once you start coding the processing steps you designed you can worry about all the detail you want. Functional design does not eliminate all the nitty gritty. It just postpones tackling them. To me that´s also an example of the SRP. Function design has the responsibility to come up with a solution to a problem posed by a single function (Entry Point). And later coding has the responsibility to implement the solution down to the last detail (i.e. statement, API-call). TDD unfortunately mixes both responsibilities. It´s just coding - and thereby trying to find detailed implementations (green phase) plus getting the design right (refactoring). To me that´s one reason why TDD has failed to deliver on its promise for many developers. Using functional units as building blocks of functional design processes can be depicted very easily. Here´s the initial process for the example problem: For each processing step draw a functional unit and label it. Choose a verb or an “action phrase” as a label, not a noun. Functional design is about activities, not state or structure. Then make the output of an upstream step the input of a downstream step. Finally think about the data that should flow between the functional units. Write the data above the arrows connecting the functional units in the direction of the data flow. Enclose the data description in brackets. That way you can clearly see if all flows have already been specified. Empty brackets mean “no data is flowing”, but nevertheless a signal is sent. A name like “list” or “strings” in brackets describes the data content. Use lower case labels for that purpose. A name starting with an upper case letter like “String” or “Customer” on the other hand signifies a data type. If you like, you also can combine descriptions with data types by separating them with a colon, e.g. (list:string) or (strings:string[]). But these are just suggestions from my practice with Flow Design. You can do it differently, if you like. Just be sure to be consistent. Flows wired-up in this manner I call one-dimensional (1D). Each functional unit just has one input and/or one output. A functional unit without an output is possible. It´s like a black hole sucking up input without producing any output. Instead it produces side effects. A functional unit without an input, though, does make much sense. When should it start to work? What´s the trigger? That´s why in the above process even the first processing step has an input. If you like, view such 1D-flows as pipelines. Data is flowing through them from left to right. But as you can see, it´s not always the same data. It get´s transformed along its passage: (args) becomes a (list) which is turned into (strings). The Principle of Mutual Oblivion A very characteristic trait of flows put together from function units is: no functional units knows another one. They are all completely independent of each other. Functional units don´t know where their input is coming from (or even when it´s gonna arrive). They just specify a range of values they can process. And they promise a certain behavior upon input arriving. Also they don´t know where their output is going. They just produce it in their own time independent of other functional units. That means at least conceptually all functional units work in parallel. Functional units don´t know their “deployment context”. They now nothing about the overall flow they are place in. They are just consuming input from some upstream, and producing output for some downstream. That makes functional units very easy to test. At least as long as they don´t depend on state or resources. I call this the Principle of Mutual Oblivion (PoMO). Functional units are oblivious of others as well as an overall context/purpose. They are just parts of a whole focused on a single responsibility. How the whole is built, how a larger goal is achieved, is of no concern to the single functional units. By building software in such a manner, functional design interestingly follows nature. Nature´s building blocks for organisms also follow the PoMO. The cells forming your body do not know each other. Take a nerve cell “controlling” a muscle cell for example:[2] The nerve cell does not know anything about muscle cells, let alone the specific muscel cell it is “attached to”. Likewise the muscle cell does not know anything about nerve cells, let a lone a specific nerve cell “attached to” it. Saying “the nerve cell is controlling the muscle cell” thus only makes sense when viewing both from the outside. “Control” is a concept of the whole, not of its parts. Control is created by wiring-up parts in a certain way. Both cells are mutually oblivious. Both just follow a contract. One produces Acetylcholine (ACh) as output, the other consumes ACh as input. Where the ACh is going, where it´s coming from neither cell cares about. Million years of evolution have led to this kind of division of labor. And million years of evolution have produced organism designs (DNA) which lead to the production of these different cell types (and many others) and also to their co-location. The result: the overall behavior of an organism. How and why this happened in nature is a mystery. For our software, though, it´s clear: functional and quality requirements needs to be fulfilled. So we as developers have to become “intelligent designers” of “software cells” which we put together to form a “software organism” which responds in satisfying ways to triggers from it´s environment. My bet is: If nature gets complex organisms working by following the PoMO, who are we to not apply this recipe for success to our much simpler “machines”? So my rule is: Wherever there is functionality to be delivered, because there is a clear Entry Point into software, design the functionality like nature would do it. Build it from mutually oblivious functional units. That´s what Flow Design is about. In that way it´s even universal, I´d say. Its notation can also be applied to biology: Never mind labeling the functional units with nouns. That´s ok in Flow Design. You´ll do that occassionally for functional units on a higher level of abstraction or when their purpose is close to hardware. Getting a cockroach to roam your bedroom takes 1,000,000 nerve cells (neurons). Getting the de-duplication program to do its job just takes 5 “software cells” (functional units). Both, though, follow the same basic principle. Translating functional units into code Moving from functional design to code is no rocket science. In fact it´s straightforward. There are two simple rules: Translate an input port to a function. Translate an output port either to a return statement in that function or to a function pointer visible to that function. The simplest translation of a functional unit is a function. That´s what you saw in the above example. Functions are mutually oblivious. That why Functional Programming likes them so much. It makes them composable. Which is the reason, nature works according to the PoMO. Let´s be clear about one thing: There is no dependency injection in nature. For all of an organism´s complexity no DI container is used. Behavior is the result of smooth cooperation between mutually oblivious building blocks. Functions will often be the adequate translation for the functional units in your designs. But not always. Take for example the case, where a processing step should not always produce an output. Maybe the purpose is to filter input. Here the functional unit consumes words and produces words. But it does not pass along every word flowing in. Some words are swallowed. Think of a spell checker. It probably should not check acronyms for correctness. There are too many of them. Or words with no more than two letters. Such words are called “stop words”. In the above picture the optionality of the output is signified by the astrisk outside the brackets. It means: Any number of (word) data items can flow from the functional unit for each input data item. It might be none or one or even more. This I call a stream of data. Such behavior cannot be translated into a function where output is generated with return. Because a function always needs to return a value. So the output port is translated into a function pointer or continuation which gets passed to the subroutine when called:[3]void filter_stop_words( string word, Action<string> onNoStopWord) { if (...check if not a stop word...) onNoStopWord(word); } If you want to be nitpicky you might call such a function pointer parameter an injection. And technically you´re right. Conceptually, though, it´s not an injection. Because the subroutine is not functionally dependent on the continuation. Firstly continuations are procedures, i.e. subroutines without a return type. Remember: Flow Design is about unidirectional data flow. Secondly the name of the formal parameter is chosen in a way as to not assume anything about downstream processing steps. onNoStopWord describes a situation (or event) within the functional unit only. Translating output ports into function pointers helps keeping functional units mutually oblivious in cases where output is optional or produced asynchronically. Either pass the function pointer to the function upon call. Or make it global by putting it on the encompassing class. Then it´s called an event. In C# that´s even an explicit feature.class Filter { public void filter_stop_words( string word) { if (...check if not a stop word...) onNoStopWord(word); } public event Action<string> onNoStopWord; } When to use a continuation and when to use an event dependens on how a functional unit is used in flows and how it´s packed together with others into classes. You´ll see examples further down the Flow Design road. Another example of 1D functional design Let´s see Flow Design once more in action using the visual notation. How about the famous word wrap kata? Robert C. Martin has posted a much cited solution including an extensive reasoning behind his TDD approach. So maybe you want to compare it to Flow Design. The function signature given is:string WordWrap(string text, int maxLineLength) {...} That´s not an Entry Point since we don´t see an application with an environment and users. Nevertheless it´s a function which is supposed to provide a certain functionality. The text passed in has to be reformatted. The input is a single line of arbitrary length consisting of words separated by spaces. The output should consist of one or more lines of a maximum length specified. If a word is longer than a the maximum line length it can be split in multiple parts each fitting in a line. Flow Design Let´s start by brainstorming the process to accomplish the feat of reformatting the text. What´s needed? Words need to be assembled into lines Words need to be extracted from the input text The resulting lines need to be assembled into the output text Words too long to fit in a line need to be split Does sound about right? I guess so. And it shows a kind of priority. Long words are a special case. So maybe there is a hint for an incremental design here. First let´s tackle “average words” (words not longer than a line). Here´s the Flow Design for this increment: The the first three bullet points turned into functional units with explicit data added. As the signature requires a text is transformed into another text. See the input of the first functional unit and the output of the last functional unit. In between no text flows, but words and lines. That´s good to see because thereby the domain is clearly represented in the design. The requirements are talking about words and lines and here they are. But note the asterisk! It´s not outside the brackets but inside. That means it´s not a stream of words or lines, but lists or sequences. For each text a sequence of words is output. For each sequence of words a sequence of lines is produced. The asterisk is used to abstract from the concrete implementation. Like with streams. Whether the list of words gets implemented as an array or an IEnumerable is not important during design. It´s an implementation detail. Does any processing step require further refinement? I don´t think so. They all look pretty “atomic” to me. And if not… I can always backtrack and refine a process step using functional design later once I´ve gained more insight into a sub-problem. Implementation The implementation is straightforward as you can imagine. The processing steps can all be translated into functions. Each can be tested easily and separately. Each has a focused responsibility. And the process flow becomes just a sequence of function calls: Easy to understand. It clearly states how word wrapping works - on a high level of abstraction. And it´s easy to evolve as you´ll see. Flow Design - Increment 2 So far only texts consisting of “average words” are wrapped correctly. Words not fitting in a line will result in lines too long. Wrapping long words is a feature of the requested functionality. Whether it´s there or not makes a difference to the user. To quickly get feedback I decided to first implement a solution without this feature. But now it´s time to add it to deliver the full scope. Fortunately Flow Design automatically leads to code following the Open Closed Principle (OCP). It´s easy to extend it - instead of changing well tested code. How´s that possible? Flow Design allows for extension of functionality by inserting functional units into the flow. That way existing functional units need not be changed. The data flow arrow between functional units is a natural extension point. No need to resort to the Strategy Pattern. No need to think ahead where extions might need to be made in the future. I just “phase in” the remaining processing step: Since neither Extract words nor Reformat know of their environment neither needs to be touched due to the “detour”. The new processing step accepts the output of the existing upstream step and produces data compatible with the existing downstream step. Implementation - Increment 2 A trivial implementation checking the assumption if this works does not do anything to split long words. The input is just passed on: Note how clean WordWrap() stays. The solution is easy to understand. A developer looking at this code sometime in the future, when a new feature needs to be build in, quickly sees how long words are dealt with. Compare this to Robert C. Martin´s solution:[4] How does this solution handle long words? Long words are not even part of the domain language present in the code. At least I need considerable time to understand the approach. Admittedly the Flow Design solution with the full implementation of long word splitting is longer than Robert C. Martin´s. At least it seems. Because his solution does not cover all the “word wrap situations” the Flow Design solution handles. Some lines would need to be added to be on par, I guess. But even then… Is a difference in LOC that important as long as it´s in the same ball park? I value understandability and openness for extension higher than saving on the last line of code. Simplicity is not just less code, it´s also clarity in design. But don´t take my word for it. Try Flow Design on larger problems and compare for yourself. What´s the easier, more straightforward way to clean code? And keep in mind: You ain´t seen all yet ;-) There´s more to Flow Design than described in this chapter. In closing I hope I was able to give you a impression of functional design that makes you hungry for more. To me it´s an inevitable step in software development. Jumping from requirements to code does not scale. And it leads to dirty code all to quickly. Some thought should be invested first. Where there is a clear Entry Point visible, it´s functionality should be designed using data flows. Because with data flows abstraction is possible. For more background on why that´s necessary read my blog article here. For now let me point out to you - if you haven´t already noticed - that Flow Design is a general purpose declarative language. It´s “programming by intention” (Shalloway et al.). Just write down how you think the solution should work on a high level of abstraction. This breaks down a large problem in smaller problems. And by following the PoMO the solutions to those smaller problems are independent of each other. So they are easy to test. Or you could even think about getting them implemented in parallel by different team members. Flow Design not only increases evolvability, but also helps becoming more productive. All team members can participate in functional design. This goes beyon collective code ownership. We´re talking collective design/architecture ownership. Because with Flow Design there is a common visual language to talk about functional design - which is the foundation for all other design activities.   PS: If you like what you read, consider getting my ebook “The Incremental Architekt´s Napkin”. It´s where I compile all the articles in this series for easier reading. I like the strictness of Function Programming - but I also find it quite hard to live by. And it certainly is not what millions of programmers are used to. Also to me it seems, the real world is full of state and side effects. So why give them such a bad image? That´s why functional design takes a more pragmatic approach. State and side effects are ok for processing steps - but be sure to follow the SRP. Don´t put too much of it into a single processing step. ? Image taken from www.physioweb.org ? My code samples are written in C#. C# sports typed function pointers called delegates. Action is such a function pointer type matching functions with signature void someName(T t). Other languages provide similar ways to work with functions as first class citizens - even Java now in version 8. I trust you find a way to map this detail of my translation to your favorite programming language. I know it works for Java, C++, Ruby, JavaScript, Python, Go. And if you´re using a Functional Programming language it´s of course a no brainer. ? Taken from his blog post “The Craftsman 62, The Dark Path”. ?

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  • Arcball Problems with UDK

    - by opdude
    I'm trying to re-create an arcball example from a Nehe, where an object can be rotated in a more realistic way while floating in the air (in my game the object is attached to the player at a distance like for example the Physics Gun) however I'm having trouble getting this to work with UDK. I have created an LGArcBall which follows the example from Nehe and I've compared outputs from this with the example code. I think where my problem lies is what I do to the Quaternion that is returned from the LGArcBall. Currently I am taking the returned Quaternion converting it to a rotation matrix. Getting the product of the last rotation (set when the object is first clicked) and then returning that into a Rotator and setting that to the objects rotation. If you could point me in the right direction that would be great, my code can be found below. class LGArcBall extends Object; var Quat StartRotation; var Vector StartVector; var float AdjustWidth, AdjustHeight, Epsilon; function SetBounds(float NewWidth, float NewHeight) { AdjustWidth = 1.0f / ((NewWidth - 1.0f) * 0.5f); AdjustHeight = 1.0f / ((NewHeight - 1.0f) * 0.5f); } function StartDrag(Vector2D startPoint, Quat rotation) { StartVector = MapToSphere(startPoint); } function Quat Update(Vector2D currentPoint) { local Vector currentVector, perp; local Quat newRot; //Map the new point to the sphere currentVector = MapToSphere(currentPoint); //Compute the vector perpendicular to the start and current perp = startVector cross currentVector; //Make sure our length is larger than Epsilon if (VSize(perp) > Epsilon) { //Return the perpendicular vector as the transform newRot.X = perp.X; newRot.Y = perp.Y; newRot.Z = perp.Z; //In the quaternion values, w is cosine (theta / 2), where //theta is the rotation angle newRot.W = startVector dot currentVector; } else { //The two vectors coincide, so return an identity transform newRot.X = 0.0f; newRot.Y = 0.0f; newRot.Z = 0.0f; newRot.W = 0.0f; } return newRot; } function Vector MapToSphere(Vector2D point) { local float x, y, length, norm; local Vector result; //Transform the mouse coords to [-1..1] //and inverse the Y coord x = (point.X * AdjustWidth) - 1.0f; y = 1.0f - (point.Y * AdjustHeight); length = (x * x) + (y * y); //If the point is mapped outside of the sphere //( length > radius squared) if (length > 1.0f) { norm = 1.0f / Sqrt(length); //Return the "normalized" vector, a point on the sphere result.X = x * norm; result.Y = y * norm; result.Z = 0.0f; } else //It's inside of the sphere { //Return a vector to the point mapped inside the sphere //sqrt(radius squared - length) result.X = x; result.Y = y; result.Z = Sqrt(1.0f - length); } return result; } DefaultProperties { Epsilon = 0.000001f } I'm then attempting to rotate that object when the mouse is dragged, with the following update code in my PlayerController. //Get Mouse Position MousePosition.X = LGMouseInterfacePlayerInput(PlayerInput).MousePosition.X; MousePosition.Y = LGMouseInterfacePlayerInput(PlayerInput).MousePosition.Y; newQuat = ArcBall.Update(MousePosition); rotMatrix = MakeRotationMatrix(QuatToRotator(newQuat)); rotMatrix = rotMatrix * LastRot; LGMoveableActor(movingPawn.CurrentUseableObject).SetPhysics(EPhysics.PHYS_Rotating); LGMoveableActor(movingPawn.CurrentUseableObject).SetRotation(MatrixGetRotator(rotMatrix));

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  • AutoMapper is not working for a Container class

    - by rboarman
    Hello, I have an AutoMapper issue that has been driving me crazy for way too long now. A similar question was also posted on the AutoMapper user site but has not gotten much love. The summary is that I have a container class that holds a Dictionary of components. The components are a derived object of a common base class. I also have a parallel structure that I am using as DTO objects to which I want to map. The error that gets generated seems to say that the mapper cannot map between two of the classes that I have included in the CreateMap calls. I think the error has to do with the fact that I have a Dictionary of objects that are not part of the container‘s hierarchy. I apologize in advance for the length of the code below. My simple test cases work. Needless to say, it’s only the more complex case that is failing. Here are the classes: #region Dto objects public class ComponentContainerDTO { public Dictionary<string, ComponentDTO> Components { get; set; } public ComponentContainerDTO() { this.Components = new Dictionary<string, ComponentDTO>(); } } public class EntityDTO : ComponentContainerDTO { public int Id { get; set; } } public class ComponentDTO { public EntityDTO Owner { get; set; } public int Id { get; set; } public string Name { get; set; } public string ComponentType { get; set; } } public class HealthDTO : ComponentDTO { public decimal CurrentHealth { get; set; } } public class PhysicalLocationDTO : ComponentDTO { public Point2D Location { get; set; } } #endregion #region Domain objects public class ComponentContainer { public Dictionary<string, Component> Components { get; set; } public ComponentContainer() { this.Components = new Dictionary<string, Component>(); } } public class Entity : ComponentContainer { public int Id { get; set; } } public class Component { public Entity Owner { get; set; } public int Id { get; set; } public string Name { get; set; } public string ComponentType { get; set; } } public class Health : Component { public decimal CurrentHealth { get; set; } } public struct Point2D { public decimal X; public decimal Y; public Point2D(decimal x, decimal y) { X = x; Y = y; } } public class PhysicalLocation : Component { public Point2D Location { get; set; } } #endregion The code: var entity = new Entity() { Id = 1 }; var healthComponent = new Health() { CurrentHealth = 100, Owner = entity, Name = "Health", Id = 2 }; entity.Components.Add("1", healthComponent); var locationComponent = new PhysicalLocation() { Location = new Point2D() { X = 1, Y = 2 }, Owner = entity, Name = "PhysicalLocation", Id = 3 }; entity.Components.Add("2", locationComponent); Mapper.CreateMap<ComponentContainer, ComponentContainerDTO>() .Include<Entity, EntityDTO>(); Mapper.CreateMap<Entity, EntityDTO>(); Mapper.CreateMap<Component, ComponentDTO>() .Include<Health, HealthDTO>() .Include<PhysicalLocation, PhysicalLocationDTO>(); Mapper.CreateMap<Component, ComponentDTO>(); Mapper.CreateMap<Health, HealthDTO>(); Mapper.CreateMap<PhysicalLocation, PhysicalLocationDTO>(); Mapper.AssertConfigurationIsValid(); var targetEntity = Mapper.Map<Entity, EntityDTO>(entity); The error when I call Map() (abbreviated stack crawls): AutoMapper.AutoMapperMappingException was unhandled Message=Trying to map MapperTest1.Entity to MapperTest1.EntityDTO. Using mapping configuration for MapperTest1.Entity to MapperTest1.EntityDTO Exception of type 'AutoMapper.AutoMapperMappingException' was thrown. Source=AutoMapper StackTrace: at AutoMapper.MappingEngine.AutoMapper.IMappingEngineRunner.Map(ResolutionContext context) . . . InnerException: AutoMapper.AutoMapperMappingException Message=Trying to map System.Collections.Generic.Dictionary`2[[System.String, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089],[MapperTest1.Component, ElasticTest1, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null]] to System.Collections.Generic.Dictionary`2[[System.String, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089],[MapperTest1.ComponentDTO, ElasticTest1, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null]]. Using mapping configuration for MapperTest1.Entity to MapperTest1.EntityDTO Destination property: Components Exception of type 'AutoMapper.AutoMapperMappingException' was thrown. Source=AutoMapper StackTrace: at AutoMapper.Mappers.TypeMapObjectMapperRegistry.PropertyMapMappingStrategy.MapPropertyValue(ResolutionContext context, IMappingEngineRunner mapper, Object mappedObject, PropertyMap propertyMap) . . InnerException: AutoMapper.AutoMapperMappingException Message=Trying to map System.Collections.Generic.Dictionary`2[[System.String, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089],[MapperTest1.Component, ElasticTest1, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null]] to System.Collections.Generic.Dictionary`2[[System.String, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089],[MapperTest1.ComponentDTO, ElasticTest1, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null]]. Using mapping configuration for MapperTest1.Entity to MapperTest1.EntityDTO Destination property: Components Exception of type 'AutoMapper.AutoMapperMappingException' was thrown. Source=AutoMapper StackTrace: at AutoMapper.MappingEngine.AutoMapper.IMappingEngineRunner.Map(ResolutionContext context) . InnerException: AutoMapper.AutoMapperMappingException Message=Trying to map MapperTest1.Component to MapperTest1.ComponentDTO. Using mapping configuration for MapperTest1.Health to MapperTest1.HealthDTO Destination property: Components Exception of type 'AutoMapper.AutoMapperMappingException' was thrown. Source=AutoMapper StackTrace: at AutoMapper.MappingEngine.AutoMapper.IMappingEngineRunner.Map(ResolutionContext context) . . InnerException: AutoMapper.AutoMapperMappingException Message=Trying to map System.Decimal to System.Decimal. Using mapping configuration for MapperTest1.Health to MapperTest1.HealthDTO Destination property: CurrentHealth Exception of type 'AutoMapper.AutoMapperMappingException' was thrown. Source=AutoMapper StackTrace: at AutoMapper.Mappers.TypeMapObjectMapperRegistry.PropertyMapMappingStrategy.MapPropertyValue(ResolutionContext context, IMappingEngineRunner mapper, Object mappedObject, PropertyMap propertyMap) . . InnerException: System.InvalidCastException Message=Unable to cast object of type 'MapperTest1.ComponentDTO' to type 'MapperTest1.HealthDTO'. Source=Anonymously Hosted DynamicMethods Assembly StackTrace: at SetCurrentHealth(Object , Object ) . . Thank you in advance. Rick

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  • Bogus InvalidOperationException (in a DataServiceRequestException)

    - by Andrei Rinea
    I am having a hard time with ADO.NET Data Services (formerly code-named Astoria) as it gives me a bogus exception when I try to insert a new entity from the silverlight client and trying in a clean project (the same code) doesn't. In both cases, however, data is correctly inserted into the database. Using Fiddler (an HTTP debugger I could see that there is no problem in the HTTP communication as I will show later in this question. The code : var ctx = new MyProject123Entities(new Uri("http://andreiri/MyProject.Data/Data.svc")); var i = new Zone() { Data = DateTime.Now, IdElement = 1 }; ctx.AddToZone(i); i.StareZone = new StareZone() { IdStareZone = 1 }; ctx.AttachTo("StareZone", i.StareZone); ctx.SetLink(i, "StareZone", i.StareZone); i.TipZone = new TipZone() { IdTipZone = 1 }; ctx.AttachTo("TipZone", i.TipZone); ctx.SetLink(i, "TipZone", i.TipZone); i.User = new User() { IdUser = 2 }; ctx.AttachTo("User", i.User); ctx.SetLink(i, "User", i.User); ctx.BeginSaveChanges(r =] ctx.EndSaveChanges(r), null); when run the last line (ctx.EndSaveChanges(r)) will throw the following exception : System.Data.Services.Client.DataServiceRequestException was unhandled by user code Message="An error occurred while processing this request." StackTrace: at System.Data.Services.Client.DataServiceContext.SaveAsyncResult.HandleBatchResponse() at System.Data.Services.Client.DataServiceContext.SaveAsyncResult.EndRequest() at System.Data.Services.Client.DataServiceContext.EndSaveChanges(IAsyncResult asyncResult) at MyProject.MainPage.[]c__DisplayClassd6.[]c__DisplayClassd8.[dashboard_PostZoneCurent]b__d5(IAsyncResult r) at System.Data.Services.Client.BaseAsyncResult.HandleCompleted() at System.Data.Services.Client.DataServiceContext.SaveAsyncResult.HandleCompleted(PerRequest pereq) at System.Data.Services.Client.DataServiceContext.SaveAsyncResult.AsyncEndRead(IAsyncResult asyncResult) at System.IO.Stream.BeginRead(Byte[] buffer, Int32 offset, Int32 count, AsyncCallback callback, Object state) at System.Data.Services.Client.DataServiceContext.SaveAsyncResult.AsyncEndGetResponse(IAsyncResult asyncResult) InnerException: System.InvalidOperationException Message="The context is already tracking a different entity with the same resource Uri." StackTrace: at System.Data.Services.Client.DataServiceContext.AttachTo(Uri identity, Uri editLink, String etag, Object entity, Boolean fail) at System.Data.Services.Client.MaterializeAtom.MoveNext() at System.Data.Services.Client.DataServiceContext.HandleResponsePost(ResourceBox entry, MaterializeAtom materializer, Uri editLink, String etag) at System.Data.Services.Client.DataServiceContext.SaveAsyncResult.[HandleBatchResponse]d__1d.MoveNext() InnerException: (there is no further information regarding the exception although the ADo.NET Data Service is configured to return detailed informations) However the row is inserted correctly and completely in the database. Using fiddler I can see that the request : <?xml version="1.0" encoding="utf-8" standalone="yes"?> <entry xmlns:d="http://schemas.microsoft.com/ado/2007/08/dataservices" xmlns:m="http://schemas.microsoft.com/ado/2007/08/dataservices/metadata" xmlns="http://www.w3.org/2005/Atom"> <category scheme="http://schemas.microsoft.com/ado/2007/08/dataservices/scheme" term="MyProject123Model.Zone" /> <title /> <updated>2009-09-11T13:36:46.917157Z</updated> <author> <name /> </author> <id /> <link href="http://andreiri/MyProject.Data/Data.svc/StareZone(1)" rel="http://schemas.microsoft.com/ado/2007/08/dataservices/related/StareZone" type="application/atom+xml;type=entry" /> <link href="http://andreiri/MyProject.Data/Data.svc/TipZone(4)" rel="http://schemas.microsoft.com/ado/2007/08/dataservices/related/TipZone" type="application/atom+xml;type=entry" /> <link href="http://andreiri/MyProject.Data/Data.svc/User(4)" rel="http://schemas.microsoft.com/ado/2007/08/dataservices/related/User" type="application/atom+xml;type=entry" /> <content type="application/xml"> <m:properties> <d:Data m:type="Edm.DateTime">2009-09-11T16:36:40.588951+03:00</d:Data> <d:Detalii>aslkdfjasldkfj</d:Detalii> <d:IdElement m:type="Edm.Int32">1</d:IdElement> <d:IdZone m:type="Edm.Int32">0</d:IdZone> <d:X_Post m:type="Edm.Decimal">587647.4705</d:X_Post> <d:X_Repost m:type="Edm.Decimal" m:null="true" /> <d:Y_Post m:type="Edm.Decimal">325783.077599999</d:Y_Post> <d:Y_Repost m:type="Edm.Decimal" m:null="true" /> </m:properties> </content> </entry> is well accepted and a successful response is returned : HTTP/1.1 201 Created Date: Fri, 11 Sep 2009 13:36:47 GMT Server: Microsoft-IIS/6.0 X-Powered-By: ASP.NET X-AspNet-Version: 2.0.50727 DataServiceVersion: 1.0; Location: http://andreiri/MyProject.Data/Data.svc/Zone(75) Cache-Control: no-cache Content-Type: application/atom+xml;charset=utf-8 Content-Length: 2213 <?xml version="1.0" encoding="utf-8" standalone="yes"?> <entry xml:base="http://andreiri/MyProject.Data/Data.svc/" xmlns:d="http://schemas.microsoft.com/ado/2007/08/dataservices" xmlns:m="http://schemas.microsoft.com/ado/2007/08/dataservices/metadata" xmlns="http://www.w3.org/2005/Atom"> <id>http://andreiri/MyProject.Data/Data.svc/Zone(75)</id> <title type="text"></title> <updated>2009-09-11T13:36:47Z</updated> <author> <name /> </author> <link rel="edit" title="Zone" href="Zone(75)" /> <link rel="http://schemas.microsoft.com/ado/2007/08/dataservices/related/CenterZone" type="application/atom+xml;type=feed" title="CenterZone" href="Zone(75)/CenterZone" /> <link rel="http://schemas.microsoft.com/ado/2007/08/dataservices/related/ZoneMobil" type="application/atom+xml;type=feed" title="ZoneMobil" href="Zone(75)/ZoneMobil" /> <link rel="http://schemas.microsoft.com/ado/2007/08/dataservices/related/StareZone" type="application/atom+xml;type=entry" title="StareZone" href="Zone(75)/StareZone" /> <link rel="http://schemas.microsoft.com/ado/2007/08/dataservices/related/TipZone" type="application/atom+xml;type=entry" title="TipZone" href="Zone(75)/TipZone" /> <link rel="http://schemas.microsoft.com/ado/2007/08/dataservices/related/User" type="application/atom+xml;type=entry" title="User" href="Zone(75)/User" /> <category term="MyProject123Model.Zone" scheme="http://schemas.microsoft.com ado/2007/08/dataservices/scheme" /> <content type="application/xml"> <m:properties> <d:IdZone m:type="Edm.Int32">75</d:IdZone> <d:X_Post m:type="Edm.Decimal">587647.4705</d:X_Post> <d:Y_Post m:type="Edm.Decimal">325783.077599999</d:Y_Post> <d:X_Repost m:type="Edm.Decimal" m:null="true" /> <d:Y_Repost m:type="Edm.Decimal" m:null="true" /> <d:Data m:type="Edm.DateTime">2009-09-11T16:36:40.588951+03:00</d:Data> <d:Detalii>aslkdfjasldkfj</d:Detalii> <d:IdElement m:type="Edm.Int32">1</d:IdElement> </m:properties> </content> </entry> Why do I get an exception? And, using this in a clean project does not throw the exception..

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  • VSS Post Backup failures for Virtual Server 2005 R2 SP1 virtual machines

    - by califguy4christ
    We've been seeing strange errors with Volume Shadow Copy services on our Virtual Server 2005 R2 SP1 host. It appears to be failing on a strange mountpoint in the C:\WINDOWS\Temp\ folders, which I believe is used by VSS to mount a writeable image file. To summarize: The Microsoft Virtual Server 2005 Writer continually goes into a failed retryable state The Virtual Server log reports errors during the Post Backup phase VSS reports errors backing up a mount point of unknown origins The mount point causes NTFS and ftdisk errors The host is x86 Windows Server 2003 Standard, SP2. The virtual machine is the same. Both use basic disks. Here is the writer state: Writer name: 'Microsoft Virtual Server 2005 Writer' Writer Id: {76afb926-87ad-4a20-a50f-cdc69412ddfc} Writer Instance Id: {78df98e2-bf19-4804-890b-15865efef3bd} State: [11] Failed Last error: Retryable error From the Virtual Server log: Virtual Server - Vss Writer - Event ID: 1035: The VSS writer for Virtual Server failed during the PostBackup phase. The guest shadow copies did not get exposed on the host machine, after mounting all the virtual hard disks of the virtual machine VMACHINE. From the Application log: VSS - None - Event ID: 12290: Volume Shadow Copy Service warning: GetVolumeInformationW( \\?\Volume{fb84bae7-87f5-11dd-9832-001cc4961ca6}\,NULL,0, NULL,NULL,[0x00000000], , 260) == 0x0000045d. hr = 0x00000000. From the System log: Ntfs - Disk - Event ID: 55: The file system structure on the disk is corrupt and unusable. Please run the chkdsk utility on the volume C:\WINDOWS\Temp\ {fb84bae7-87f5-11dd-9832-001cc49.... My current theory is that VSS creates a mount point for an image file of the VHD, then the software panics for some reason, leaving everything in an inconsistent state. Removing the mount point doesn't resolve the problem. All of the other disks check out fine with CHKDSK. There's no exclusion option for VHDs or to turn off online backups. Has anyone seen this kind of thing before or point me in the right direction for getting more information about the mount point and it's origins? I haven't been able to trace what application is creating that mount point.

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  • Box2dx: Usage of World.QueryAABB?

    - by Rosarch
    I'm using Box2dx with C#/XNA. I'm trying to write a function that determines if a body could exist in a given point without colliding with anything: /// <summary> /// Can gameObject exist with start Point without colliding with anything? /// </summary> internal bool IsAvailableArea(GameObjectModel model, Vector2 point) { Vector2 originalPosition = model.Body.Position; model.Body.Position = point; // less risky would be to use a deep clone AABB collisionBox; model.Body.GetFixtureList().GetAABB(out collisionBox); // how is this supposed to work? physicsWorld.QueryAABB(x => true, ref collisionBox); model.Body.Position = originalPosition; return true; } Is there a better way to go about doing this? How is World.QueryAABB supposed to work? Here is an earlier attempt. It is broken; it always returns false. /// <summary> /// Can gameObject exist with start Point without colliding with anything? /// </summary> internal bool IsAvailableArea(GameObjectModel model, Vector2 point) { Vector2 originalPosition = model.Body.Position; model.Body.Position = point; // less risky would be to use a deep clone AABB collisionBox; model.Body.GetFixtureList().GetAABB(out collisionBox); ICollection<GameObjectController> gameObjects = worldQueryEngine.GameObjectsForPredicate(x => ! x.Model.Passable); foreach (GameObjectController controller in gameObjects) { AABB potentialCollidingBox; controller.Model.Body.GetFixtureList().GetAABB(out potentialCollidingBox); if (AABB.TestOverlap(ref collisionBox, ref potentialCollidingBox)) { model.Body.Position = originalPosition; return false; // there is something that will collide at this point } } model.Body.Position = originalPosition; return true; }

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  • OnContextMenu() not working in view class

    - by Anu
    Hi, i have a popup menu for contextmenu.And i wrote the function for each menu in CMainframe. I have OnContextMenu() in each view class and in one dialog class.Its works fine in Dialog class.But not in View class.Codings are below: CMainframe funciton: void CMainFrame::OnUpdateFptrend(CCmdUI* pCmdUI) { ((CMainFrame *)AfxGetMainWnd())->SendMessage(WM_COMMAND,ID_TRENDVIEW,NULL); } void CMainFrame::OnUpdateFptuning(CCmdUI* pCmdUI) { ((CMainFrame *)AfxGetMainWnd())->SendMessageWM_COMMAND,ID_TUNINGVIEW,NULL); } Dialog class Contextmenu: void CFacePlate::OnContextMenu(CWnd* pWnd, CPoint point) { CMenu mnuPopup; mnuPopup.LoadMenu(IDR_FPMENU); CRect rBarRect; rBarRect.left = rBarRect.top = 0; rBarRect.right = 1000;rBarRect.bottom = 300; CMenu *mnuPopupMenu = mnuPopup.GetSubMenu(0); ASSERT(mnuPopupMenu); if( rBarRect.PtInRect(point) ) mnuPopupMenu->TrackPopupMenu(TPM_LEFTALIGN | TPM_RIGHTBUTTON, point.x, point.y, this); } View class: void CGroupView::OnContextMenu(CWnd* pWnd, CPoint point) { CMenu mnuPopup; mnuPopup.LoadMenu(IDR_FPMENU); CRect rBarRect; rBarRect.left = rBarRect.top = 0; rBarRect.right = 1150;rBarRect.bottom = 390; CMenu *mnuPopupMenu = mnuPopup.GetSubMenu(0); ASSERT(mnuPopupMenu); if( rBarRect.PtInRect(point) ) mnuPopupMenu->TrackPopupMenu(TPM_LEFTALIGN | TPM_RIGHTBUTTON, point.x, point.y, this); } When i press popup menu from Faceplate(Dialogclass),it goes to Mainframe function.At the same time when i press menu from any view class,it doesnot go to Mainframe function.Why its like that?

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  • What points to be used for Drawing Hexagonal Shaped Button

    - by Durga
    Using below code I am able to draw arrow shaped button(shown below) ,but I want to draw hexagone(shown below as result image) ,so that I can use png image of size 175x154 as button image ,What Points I need to use to draw this ? and i need to to draw 6 such buttons ,how do i achieve this ? private void Parent_Load(object sender, EventArgs e) { // Define the points in the polygonal path. Point[] pts = { new Point( 20, 60), new Point(140, 60), new Point(140, 20), new Point(220, 100), new Point(140, 180), new Point(140, 140), new Point( 20, 140) }; // Make the GraphicsPath. GraphicsPath polygon_path = new GraphicsPath(FillMode.Winding); polygon_path.AddPolygon(pts); // Convert the GraphicsPath into a Region. Region polygon_region = new Region(polygon_path); // Constrain the button to the region. btnExam.Region = polygon_region; // Make the button big enough to hold the whole region. btnExam.SetBounds( btnExam.Location.X, btnExam.Location.Y, pts[3].X + 5, pts[4].Y + 5); }

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  • Can someone confirm how Microsoft Excel 2007 internally represents numbers?

    - by Jon
    I know the IEEE 754 floating point standard by heart as I had to learn it for an exam. I know exactly how floating point numbers are used and the problems that they can have. I can manually do any operation on the binary representation of floating point numbers. However, I have not found a single source which unambiguously states that excel uses 64 bit floating point numbers to internally represent every single cell "type" in excel except for text. I have no idea whether some of the types use signed or unsigned integers and some use 64 bit floating point. I have found literally trillions of articles which 1) describe floating point numbers and then 2) talk about being careful with excel because of floating point numbers. I have not found a single statement saying "all types are 64 bit floating point numbers except text". I have not found a single statement which says "changing the type of a cell only changes its visual representation and not its internal representation, unless you change the type from text to some other type which is not text or you change some other type which is not text to text". This is literally all I want to know, and it's so simple and axiomatic that I am amazed that I can find trillions of articles and pages which talk around these statements but do not state them directly.

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  • Need help with shell script

    - by via-point
    I am a total newbie to Shell Scripting so please bear with me. I need to create a shell script called script1 that will calculate and then display letter grade of ABC2345. Read in the following grades from keyboard: Assignments 40% Test1 15% Test2 15% Final exam 30% Calculate and display the number grade using the weight of each factor above Convert the number grade to letter grade using the table below: Number Grade Letter Grade 90 - 100 A+ 85 - 89 A 80 - 84 77 - 79 B+ 73 - 76 B 70 - 72 B- 67 - 69 C+ 63 - 66 C 60 - 62 C- 57 - 59 D+ 53 - 56 D 50 - 52 D- 0 - 49 F Any help would be appreciated :) Thank you!

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