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  • Why doesn't Firefox cache my images and CSS

    - by Richard A
    I am using IIS7, I have already set up the following. But when I run Firefox it seems not to cache any of my images even with "remember history" set. <?xml version="1.0" encoding="UTF-8"?> <configuration> <system.webServer> <staticContent> <clientCache cacheControlCustom="public" cacheControlMode="UseMaxAge" cacheControlMaxAge="7.00:00:00" /> </staticContent> </system.webServer> </configuration> However when I use Firebug it still points to Firefox not caching images and CSS: public,max-age=604800 Content-Type text/css Content-Encoding gzip Last-Modified Mon, 27 Jun 2011 03:53:22 GMT Accept-Ranges bytes Etag "507968c27d34cc1:0" Vary Accept-Encoding Server Microsoft-IIS/7.5 X-Powered-By ASP.NET Date Mon, 27 Jun 2011 13:06:41 GMT Content-Length 5067 Request Headersview source Host www.xx.com User-Agent Mozilla/5.0 (Windows NT 6.1; rv:2.0.1) Gecko/20100101 Firefox/4.0.1 Accept text/css,*/*;q=0.1 Accept-Language en-us,en;q=0.5 Accept-Encoding gzip, deflate Accept-Charset ISO-8859-1,utf-8;q=0.7,*;q=0.7 Keep-Alive 115 Connection keep-alive Referer http://www.xx.com/ Cookie __utma=62996397.135679654.1309106351.1309159743.1309164158.8; __utmz=62996397.1309106351.1.1.utmcsr=(direct)|utmccn=(direct)|utmcmd=(none); __utmc=62996397

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  • Calculate travel time on road map with semaphores

    - by Ivansek
    I have a road map with intersections. At intersections there are semaphores. For each semaphore I generate a red light time and green light time which are represented with syntax [R:T1, G:T2], for example: 119 185 250 A ------- B: [R:6, G:4] ------ C: [R:5, G:5] ------ D I want to calculate a car travel time from A - D. Now I do this with this pseudo code: function get_travel_time(semaphores_configuration) { time = 0; for( i=1; i<path.length;i++) { prev_node = path[i-1]; next_node = path[i]); cost = cost_between(prev_node, next_node) time += (cost/movement_speed) // movement_speed = 50px per second light_times = get_light_times(path[i], semaphore_configurations) lights_cycle = get_lights_cycle(light_times) // Eg: [R,R,R,G,G,G,G], where [R:3, G:4] lights_sum = light_times.green_time+light_times.red_light; // Lights cycle time light = lights_cycle[cost%lights_sum]; if( light == "R" ) { time += light_times.red_light; } } return time; } So for distance 119 between A and B travel time is, 119/50 = 2.38s ( exactly mesaured time is between 2.5s and 2.6s), then we add time if we came at a red light when at B. If we came at a red light is calculated with lines: lights_cycle = get_lights_cycle(light_times) // Eg: [R,R,R,G,G,G,G], where [R:3, G:4] lights_sum = light_times.green_time+light_times.red_light light = lights_cycle[cost%lights_sum]; if( light == "R" ) { time += light_times.red_light; } This pseudo code doesn't calculate exactly the same times as they are mesaured, but the calculations are very close to them. Any idea how I would calculate this?

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  • How to handle key in PhP array if the key contains japanese characters [migrated]

    - by Jim Thio
    I have this array: [ID] => ????????-???????????__35.79_139.72 [Email] => [InBuildingAddress] => [Price] => [Street] => [Title] => ???????? ??????????? [Website] => [Zip] => [Rating Star] => 0 [Rating Weight] => 0 [Latitude] => 35.7865334803033 [Longitude] => 139.716800710514 [Building] => [City] => Unknown_Japan [OpeningHour] => [TimeStamp] => 0000-00-00 00:00:00 [CountViews] => 0 Then I do something like this: $output[$info['ID']]=$info; //mess up here $tes=$info['ID']['Title']; Well guess what it messes up. Basically even though the content of an array in PhP can be Japanese. Is this true? What's wrong. The error I got is: Debug Warning: /sdfdsfdf/api/test2.php line 36 - Cannot find element ????????-???????????__35.79_139.72 in variable Debug Warning: /sdfdsfdf/api/test2.php line 36 - main() [function.main]: It is not safe to rely on the system's timezone settings. You are required to use the date.timezone setting or the date_default_timezone_set() function. In case you used any of those methods and you are still getting this warning, you most likely misspelled the timezone identifier. We selected 'Asia/Krasnoyarsk' for '7.0/no DST' instead So many question mark Why is this happening. What's really going on inside PhP? Where can I learn more of such things. Most importantly, what would be the best way to handle this situation. Should I tell PhP to internally always use UTF-8? Does PhP array inherenty cannot use non ascii id?

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  • Is there a canonical source supporting "all-surrogates"?

    - by user61852
    Background The "all-PK-must-be-surrogates" approach is not present in Codd's Relational Model or any SQL Standard (ANSI, ISO or other). Canonical books seems to elude this restrictions too. Oracle's own data dictionary scheme uses natural keys in some tables and surrogate keys in other tables. I mention this because these people must know a thing or two about RDBMS design. PPDM (Professional Petroleum Data Management Association) recommend the same canonical books do: Use surrogate keys as primary keys when: There are no natural or business keys Natural or business keys are bad ( change often ) The value of natural or business key is not known at the time of inserting record Multicolumn natural keys ( usually several FK ) exceed three columns, which makes joins too verbose. Also I have not found canonical source that says natural keys need to be immutable. All I find is that they need to be very estable, i.e need to be changed only in very rare ocassions, if ever. I mention PPDM because these people must know a thing or two about RDBMS design too. The origins of the "all-surrogates" approach seems to come from recommendations from some ORM frameworks. It's true that the approach allows for rapid database modeling by not having to do much business analysis, but at the expense of maintainability and readability of the SQL code. Much prevision is made for something that may or may not happen in the future ( the natural PK changed so we will have to use the RDBMS cascade update funtionality ) at the expense of day-to-day task like having to join more tables in every query and having to write code for importing data between databases, an otherwise very strightfoward procedure (due to the need to avoid PK colisions and having to create stage/equivalence tables beforehand ). Other argument is that indexes based on integers are faster, but that has to be supported with benchmarks. Obviously, long, varying varchars are not good for PK. But indexes based on short, fix-length varchar are almost as fast as integers. The questions - Is there any canonical source that supports the "all-PK-must-be-surrogates" approach ? - Has Codd's relational model been superceded by a newer relational model ?

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  • Why doesn't Firefox cache my images and CSS

    - by Richard A
    I am using IIS7, I have already set up the following. But when I run Firefox it seems not to cache any of my images even with "remember history" set. <?xml version="1.0" encoding="UTF-8"?> <configuration> <system.webServer> <staticContent> <clientCache cacheControlCustom="public" cacheControlMode="UseMaxAge" cacheControlMaxAge="7.00:00:00" /> </staticContent> </system.webServer> </configuration> However when I use Firebug it still points to Firefox not caching images and CSS: public,max-age=604800 Content-Type text/css Content-Encoding gzip Last-Modified Mon, 27 Jun 2011 03:53:22 GMT Accept-Ranges bytes Etag "507968c27d34cc1:0" Vary Accept-Encoding Server Microsoft-IIS/7.5 X-Powered-By ASP.NET Date Mon, 27 Jun 2011 13:06:41 GMT Content-Length 5067 Request Headersview source Host www.xx.com User-Agent Mozilla/5.0 (Windows NT 6.1; rv:2.0.1) Gecko/20100101 Firefox/4.0.1 Accept text/css,*/*;q=0.1 Accept-Language en-us,en;q=0.5 Accept-Encoding gzip, deflate Accept-Charset ISO-8859-1,utf-8;q=0.7,*;q=0.7 Keep-Alive 115 Connection keep-alive Referer http://www.xx.com/ Cookie __utma=62996397.135679654.1309106351.1309159743.1309164158.8; __utmz=62996397.1309106351.1.1.utmcsr=(direct)|utmccn=(direct)|utmcmd=(none); __utmc=62996397

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  • Disappearring instances of VertexPositionColor using MonoGame

    - by Rosko
    I am a complete beginner in graphics developing with XNA/Monogame. Started my own project using Monogame 3.0 for WinRT. I have this unexplainable issue that some of the vertices disappear while doing some updates on them. Basically, it is a game with balls who collide with the walls and with each other and in certain conditions they explode. When they explode they disappear. Here is a video demonstrating the issue. I used wireframes so that it is easier to see how vertices are missing. The perfect exploding balls are the ones which are result by user input with mouse clicking. Thanks for the help. The situations is: I draw user primitives with triangle strips using like this graphicsDevice.DrawUserPrimitives<VertexPositionColor>(PrimitiveType.TriangleStrip, circleVertices, 0, primitiveCount); All of the primitives are in the z-plane (z = 0), I thought that it is the culling in action. I tried setting the culling mode to none but it did not help. Here is the code responsible for the explosion private void Explode(GameTime gameTime, ref List<Circle> circles) { if (this.isExploding) { for (int i = 0; i < this.circleVertices.Length; i++) { if (this.circleVertices[i] != this.circleCenter) { if (Vector3.Distance(this.circleVertices[i].Position, this.circleCenter.Position) < this.explosionRadius * precisionCoefficient) { var explosionVector = this.circleVertices[i].Position - this.circleCenter.Position; explosionVector.Normalize(); explosionVector *= explosionSpeed; circleVertices[i].Position += explosionVector * (float)gameTime.ElapsedGameTime.TotalSeconds; } else { circles.Remove(this); } } } } } I'd be really greatful if anyone has suggestions about how to fix this issue.

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  • Interpolation between two 3D points?

    - by meds
    I'm working with some splines which define a path a character follows (you can see a gameplay video here to get a better understanding of what's going on: http://www.youtube.com/watch?v=BndobjOiZ6g). Basically the characters 'forward' look direction is set to the 'forward' direction of the spline and when players tilt their phone left and right the character is strafed along its 'right' coordinate. The issue with this is (rather obviously) in performance, interpolating over a spline to find the nearest position and tangent relative to the player is an incredibly costly operation. To get by this I cache a finite number of positions in what I call 'SplineDetails', the class is as follows: public class SplineDetails { public SplineDetails() { Forward = Vector3.forward; Position = Vector3.one * float.MaxValue; Alpha = -1; } public float Alpha; // [0,1] measured along length of spline where 0 is the initial point and 1 is the end point of the spline public Vector3 Position; // the point of the spline at this alpha public Vector3 Forward; // the forward tangent of the spline at this alpha } I populate this with say 30 coordinates and I can give a rough estimate of a coordinate and 'forward' based on a position past in. It's not as accurate but it's much faster. But now I'd like to make the system work better by estimating positions and 'forward' directions by interpolating between two of the cached points though I'm stuck trying to figure out some logic. My first problem is, how can I determine between which two points the object is? Given each point can be placed at different intervals along the spline it could mean that two points in front or behind the object can be closer to the object. The other problem is to figure out the proportion between the two paths it's between, i.e. if there is a point a at coordinate (0,0,0) and point b at coordinate (1,0,0) if the object is at position (0.5,0,0) then the result it should give is '0.5' (as it is equal distance away from point a and point b). That's a simple example, but what if the object is at coordinate (0.5,3,0) for example?

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  • Is the way I'm implementing my genetic algorithm right?

    - by Mhjr
    In my graduation project, I am asked to use a genetic algorithm (any variation of it can be chosen) to generate valid timetables. What I did was make a simple program that generates unique sequences representing genes, the sequence is described below: (sorry if it's mathematically incorrect) The only variable in the sequence is the room element, so basically the program takes a tree that goes like this: [Course] -(contains)-> [Units] -(contains)-> [Offerings] -(contains)-> [Instructors] -(contains)-> [Rooms] Each course can have n units (duplicates). Each unit can have n offerings (lectures,lab session, excercises,...). Each offering has only 1 instructor. Each instructor (or the whole lecture composed from the four elements of the sequence) has multiple rooms. When a timetable is initialized, one of these sequences that differ in rooms will be taken into the timetable, so the difference in genes (sequences) of each timetable will be just the rooms random choice and the difference between chromosomes (timetables) will be time placements of these genes (sequences). My question is, before I proceed in implementing what I described, is it valid? Is the representation used here for chromosomes a permutation representation?

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  • What are the requirements to test a website using jquery.get() ? [migrated]

    - by Frankie
    I am working on a simple website. It has to search quite a few text files in different sub-folders. The rest of the page uses jquery, so I would like to use it for this also. The function I am looking at is .get() for downloading the files. So my main question is, can I test this on my local computer (Ubuntu Linux) or do I have to have it uploaded to a server? Also, if there's a better way to go about this, that would be nice to know. However, I'm more worried about getting it working. Thanks, Frankie PS: Heres the JS/jQuery code for downloading the files to an array. g_lists = new Array(); $(":checkbox").each(function(i){ if ($(this).attr("name") != "0") { var path = "../" + $(this).attr("name") + ".txt"; $("#bot").append("<br />" + path); // debug $.get(path, function(data){ g_lists[i] = data; $("#bot").html(data); }); } else { g_lists[i] = ""; } }); Edit: Just a note about the path variable. I think it's correct, but I'm not 100% sure. I'm new to web development. Here's some examples it produces and the directory tree of the site. Maybe it will help, can't hurt. . +-- include ¦   +-- jquery.js ¦   +-- load.js +-- index.xhtml +-- style.css +-- txt    +-- Scripting_Tools    +-- Editors.txt    +-- Other.txt Examples of path: ../txt/Scripting_Tools/Editors.txt ../txt/Scripting_Tools/Other.txt Well I'm a new user, so I can't "answer" my own question, so I'll just post it here: After asking for help on a IRC chat channel specific to jQuery, I was told I could use this on a local host. To do this I installed Apache web server, and copied my site into it's directory. More information on setting it up can be found here: http://www.howtoforge.com/ubuntu_debian_lamp_server Then to run the site I navigated my browser to "localhost" and everything works.

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  • Is it considered poor programming to do this with xna components?

    - by Rob
    I created my own Menu System that is event driven. In order to have a loading screen and multithreaded loading to work, I devised this sort of implementation: //Let's check if the game is done loading. if (_game != null) { _gameLoaded = _game.DoneLoading; } //This means the game is loading still, //therefore the loading screen should be active. if (!_gameLoaded && _gameActive) { _gameScreenList[2].UpdateMenu(); } //The loading screen was selected. if (_gameScreenList[2].CurrentState == GameScreen.State.Shown && !_gameActive) { Components.Add(_game = new ParadoxGame(this)); _game.Initialize(); //Initializes the Game so that the loading can begin. _gameActive = true; } In the XNA Game Component that contains the actual game, in the LoadContent method I simply created a new Thread that calls another method ThreadLoad that has all the actual loading. I also have a boolean variable called DoneLoading in the XNA Game Component that is set to true at the end of the ThreadLoad. I am wondering if this is a poor implementation.

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  • How can I get cross-browser consistent behavior for TR heights within a table with a set height? [migrated]

    - by Dan
    I have an arbitrary number of tables with an arbitrary number of rows in each, and all tables are the same height. My initial approach was to just set the overall height of the table and hope the rows were smart enough to distribute themselves appropriately. That's not the case. I have 4 different behaviors going on with 4 browsers, but I need them to all render at the very least in a similar way. Safari & Chrome (WebKit): All rows are equal height, creating scroll bars as needed and fitting within table height. Firefox: All rows are the height necessary to fit their content, with the remaining rows overflowing out of the table. Additionally, If the content of the rows does not take up all of the height, only the part of the table with content in it takes the background (though it seems, through use of Firebug, that the actual table [and TR] extend to the bottom of the proper table height). IE: All rows are the height necessary to fit their content, with the remaining rows overflowing out of the table. Obviously this only includes one version of each browser and additional variation would likely appear with more being tested. Ideally, a solution where the browser renders TRs with less content smaller than those with larger content, while still using scrolling within the variable height TRs when the overall height of the table is not enough would be optimum. I could potentially see a solution to achieve that with JS, but can it be done with CSS? Or, if not, can the behavior that WebKit displays be made to work across the browsers? Thanks! PS: Example can be found here.

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  • How to pass one float as four unsigned chars to shader by glVertexPointAttrib?

    - by Kog
    For each vertex I use two floats as position and four unsigned bytes as color. I want to store all of them in one table, so I tried casting those four unsigned bytes to one float, but I am unable to do that correctly... All in all, my tests came to one point: GLfloat vertices[] = { 1.0f, 0.5f, 0, 1.0f, 0, 0 }; glEnableVertexAttribArray(0); glVertexAttribPointer(0, 2, GL_FLOAT, GL_FALSE, 2 * sizeof(float), vertices); // VER1 - draws red triangle // unsigned char colors[] = { 0xff, 0, 0, 0xff, 0xff, 0, 0, 0xff, 0xff, 0, 0, // 0xff }; // glEnableVertexAttribArray(1); // glVertexAttribPointer(1, 4, GL_UNSIGNED_BYTE, GL_TRUE, 4 * sizeof(GLubyte), // colors); // VER2 - draws greenish triangle (not "pure" green) // float f = 255 << 24 | 255; //Hex:0xff0000ff // float colors2[] = { f, f, f }; // glEnableVertexAttribArray(1); // glVertexAttribPointer(1, 4, GL_UNSIGNED_BYTE, GL_TRUE, 4 * sizeof(GLubyte), // colors2); // VER3 - draws red triangle int i = 255 << 24 | 255; //Hex:0xff0000ff int colors3[] = { i, i, i }; glEnableVertexAttribArray(1); glVertexAttribPointer(1, 4, GL_UNSIGNED_BYTE, GL_TRUE, 4 * sizeof(GLubyte), colors3); glDrawArrays(GL_TRIANGLES, 0, 3); Above code is used to draw one simple red triangle. My question is - why do versions 1 and 3 work correctly, while version 2 draws some greenish triangle? Hex values are one I read by marking variable during debug. They are equal for version 2 and 3 - so what causes the difference?

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  • Views : ViewControllers, many to one, or one to one?

    - by conor
    I have developed an Android application where, typically, each view (layout.xml) displayed on the screen has it's own corresponding fragment (for the purpose of this question I may refer to this as a ViewController). These views and Fragments/ViewControllers are appropriately named to reflect what they display. So this has the effect of allowing the programmer to easily pinpoint the files associated with what they see on any given screen. The above refers to the one to one part of my question. Please note that with the above there are a few exceptions where very similar is displayed on two views so the ViewController is used for two views. (Using a simple switch (type) to determine what layout.xml file to load) On the flip side. I am currently working on the iOS version of the same app, which I didn't develop. It seems that they are adopting more of a one-to-many (ViewController:View) approach. There appears to be one ViewController that handles the display logic for many different types of views. In the ViewController are an assortment of boolean flags and arrays of data (to be displayed) that are used to determine what view to load and how to display it. This seems very cumbersome to me and coupled with no comments/ambiguous variable names I am finding it very difficult to implement changes into the project. What do you guys think of the two approaches? Which one would you prefer? I'm really considering putting in some extra time at work to refactor the iOS into a more 1:1 oriented approach. My reasoning for 1:1 over M:1 is that of modularity and legibility. After all, don't some people measure the quality of code based on how easy it is for another developer to pick up the reigns or how easy it is to pull a piece of code and use it somewhere else?

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  • Estimate angle to launch missile, maths question

    - by Jonathan
    I've been working on this for an hour or two now and my maths really isn't my strong suit which is definitely not a good thing for a game programmer but that shouldn't stop me enjoying a hobby surely? After a few failed attempts I was hoping someone else out there could help so here's the situation. I'm trying to implement a bit of faked intelligence when the A.I fires it's missiles at a target in a 2D game world. By predicting the likely position the target will be in given it's current velocity and the time it will take the missile to reach it's target. I created an image to demonstrate my thinking: http://i.imgur.com/SFmU3.png which also contains the logic I use for accelerating the missile after launch. The ship that fires the missile can fire within a total of 40 degree angle, 20 either side of itself, but this could likely become variable. My current attempt was to break the space between the two lines into segments which match the targets width. Then calculate the time it would take the missile to get to that location using the formula. So for each iteration of this we total up the values and that tells us the distance travelled, ad it would then just need compared to distance to the segment. startVelocity * ((startVelocity * acceleration)^(currentframe-1) So for example. If we start at a velocity of 1f/frame with an acceleration of 0.1f the formula, at frame 4, would be 1 * (1.1^3) = 1.331 But I quickly realized I was getting lost when trying to put this into practice. Does this seem like a correct starting point or am I going completely the wrong way about it? Any pointers would help me greatly. Maths really isn't my strong suit so I get easily lost in these matters and don't even really know a good phrase to search for with this. So I guess in summary my question is more about the correct way to approach this problem and any additional code samples on top of that would be great but I'm not averse to working out the complete code from helpful pointers.

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  • Visually and audibly unambiguous subset of the Latin alphabet?

    - by elliot42
    Imagine you give someone a card with the code "5SBDO0" on it. In some fonts, the letter "S" is difficult to visually distinguish from the number five, (as with number zero and letter "O"). Reading the code out loud, it might be difficult to distinguish "B" from "D", necessitating saying "B as in boy," "D as in dog," or using a "phonetic alphabet" instead. What's the biggest subset of letters and numbers that will, in most cases, both look unambiguous visually and sound unambiguous when read aloud? Background: We want to generate a short string that can encode as many values as possible while still being easy to communicate. Imagine you have a 6-character string, "123456". In base 10 this can encode 10^6 values. In hex "1B23DF" you can encode 16^6 values in the same number of characters, but this can sound ambiguous when read aloud. ("B" vs. "D") Likewise for any string of N characters, you get (size of alphabet)^N values. The string is limited to a length of about six characters, due to wanting to fit easily within the capacity of human working memory capacity. Thus to find the max number of values we can encode, we need to find that largest unambiguous set of letters/numbers. There's no reason we can't consider the letters G-Z, and some common punctuation, but I don't want to have to go manually pairwise compare "does G sound like A?", "does G sound like B?", "does G sound like C" myself. As we know this would be O(n^2) linguistic work to do =)...

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  • How to manage Areas/Levels in an RPG?

    - by Hexlan
    I'm working on an RPG and I'm trying to figure out how to manage the different levels/areas in the game. Currently I create a new state (source file) for every area, defining its unique aspects. My concern is that as the game grows the number of class files will become unmanageable with all the towns, houses, shops, dungeons, etc. that I need to keep track of. I would also prefer to separate my levels from the source code because non-programmer members of the team will be creating levels, and I would like the engine to be as free from game specific code as possible. I'm thinking of creating a class that provides all the functions that will be the same between all the levels/areas with a unique member variable that can be used to look up level specifics from data. This way I only need to define level/area once in the code, but can create multiple instances each with its own unique aspects provided by data. Is this a good way to go about solving the issue? Is there a better way to handle a growing number of levels?

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  • Particle trajectory smoothing: where to do the simulation?

    - by nkint
    I have a particle system in which I have particles that are moving to a target and the new targets are received via network. The list of new target are some noisy coordinates of a moving target stored in the server that I want to smooth in the client. For doing the smoothing and the particle I wrote a simple particle engine with standard euler integration model. So, my pseudo code is something like that: # pseudo code class Particle: def update(): # do euler motion model integration: # if the distance to the target is more than a limit # add a new force to the accelleration # seeking the target, # and add the accelleration to velocity # and velocity to the position positionHistory.push_back(position); if history.length > historySize : history.pop_front() class ParticleEngine: particleById = dict() # an associative array # where the keys are the id # and particle istances are sotred as values # this method is called each time a new tcp packet is received and parsed def setNetTarget(int id, Vec2D new_target): particleById[id].setNewTarget(new_target) # this method is called each new frame def draw(): for p in particleById.values: p.update() beginVertex(LINE_STRIP) for v in p.positionHistory: vertex(v.x, v.y) endVertex() The new target that are arriving are noisy but setting some accelleration/velocity parameters let the particle to have a smoothed trajectories. But if a particle trajectory is a circle after a while the particle position converge to the center (a normal behaviour of euler integration model). So I decided to change the simulation and use some other interpolation (spline?) or smooth method (kalman filter?) between the targets. Something like: switch( INTERPOLATION_MODEL ): case EULER_MOTION: ... case HERMITE_INTERPOLATION: ... case SPLINE_INTERPOLATION: ... case KALMAN_FILTER_SMOOTHING: ... Now my question: where to write the motion simulation / trajectory interpolation? In the Particle? So I will have some Particle subclass like ParticleEuler, ParticleSpline, ParticleKalman, etc..? Or in the particle engine?

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  • Are long methods always bad?

    - by wobbily_col
    So looking around earlier I noticed some comments about long methods being bad practice. I am not sure I always agree that long methods are bad (and would like opinions from others). For example I have some Django views that do a bit of processing of the objects before sending them to the view, a long method being 350 lines of code. I have my code written so that it deals with the paramaters - sorting / filtering the queryset, then bit by bit does some processing on the objects my query has returned. So the processing is mainly conditional aggregation, that has complex enough rules it can't easily be done in the database, so I have some variables declared outside the main loop then get altered during the loop. varaible_1 = 0 variable_2 = 0 for object in queryset : if object.condition_condition_a and variable_2 > 0 : variable 1+= 1 ..... ... . more conditions to alter the variables return queryset, and context So according to the theory I should factor out all the code into smaller methods, so That I have the view method as being maximum one page long. However having worked on various code bases in the past, I sometimes find it makes the code less readable, when you need to constantly jump from one method to the next figuring out all the parts of it, while keeping the outermost method in your head. I find that having a long method that is well formatted, you can see the logic more easily, as it isn't getting hidden away in inner methods. I could factor out the code into smaller methods, but often there is is an inner loop being used for two or three things, so it would result in more complex code, or methods that don't do one thing but two or three (alternatively I could repeat inner loops for each task, but then there will be a performance hit). So is there a case that long methods are not always bad? Is there always a case for writing methods, when they will only be used in one place?

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  • How to represent a graph with multiple edges allowed between nodes and edges that can selectively disappear

    - by Pops
    I'm trying to figure out what sort of data structure to use for modeling some hypothetical, idealized network usage. In my scenario, a number of users who are hostile to each other are all trying to form networks of computers where all potential connections are known. The computers that one user needs to connect may not be the same as the ones another user needs to connect, though; user 1 might need to connect computers A, B and D while user 2 might need to connect computers B, C and E. Image generated with the help of NCTM Graph Creator I think the core of this is going to be an undirected cyclic graph, with nodes representing computers and edges representing Ethernet cables. However, due to the nature of the scenario, there are a few uncommon features that rule out adjacency lists and adjacency matrices (at least, without non-trivial modifications): edges can become restricted-use; that is, if one user acquires a given network connection, no other user may use that connection in the example, the green user cannot possibly connect to computer A, but the red user has connected B to E despite not having a direct link between them in some cases, a given pair of nodes will be connected by more than one edge in the example, there are two independent cables running from D to E, so the green and blue users were both able to connect those machines directly; however, red can no longer make such a connection if two computers are connected by more than one cable, each user may own no more than one of those cables I'll need to do several operations on this graph, such as: determining whether any particular pair of computers is connected for a given user identifying the optimal path for a given user to connect target computers identifying the highest-latency computer connection for a given user (i.e. longest path without branching) My first thought was to simply create a collection of all of the edges, but that's terrible for searching. The best thing I can think to do now is to modify an adjacency list so that each item in the list contains not only the edge length but also its cost and current owner. Is this a sensible approach? Assuming space is not a concern, would it be reasonable to create multiple copies of the graph (one for each user) rather than a single graph?

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  • Making particle bounce off a line with friction

    - by Dlaor
    So I'm making a game and I need a particle to bounce off a line. I've got this so far: public static Vector2f Reflect(this Vector2f vec, Vector2f axis) //vec is velocity { Vector2f result = vec - 2f * axis * axis.Dot(vec); return result; } Which works fine, but then I decided I wanted to be able to change the bounciness and friction of the bounce. I got bounciness down... public static Vector2f Reflect(this Vector2f vec, Vector2f axis, float bounciness) //Bounciness goes from 0 to 1, 0 being not bouncy and 1 being perfectly bouncy { var reflect = (1 + bounciness); //2f Vector2f result = vec - reflect * axis * axis.Dot(vec); return result; } But when I tried to add friction, everything went to hell and back... public static Vector2f Reflect(this Vector2f vec, Vector2f axis, float bounciness, float friction) //Does not work at all! { var reflect = (1 + bounciness); //2f Vector2f subtract = reflect * axis * axis.Dot(vec); Vector2f subtract2 = axis * axis.Dot(vec); Vector2f result = vec - subtract; result -= axis.PerpendicularLeft() * subtract2.Length() * friction; return result; } Any physics guys willing to help me out with this? (if you're not sure what I mean with the friction of a bounce see this: http://www.metanetsoftware.com/technique/diagrams/A-1_particle_collision.swf)

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  • ODBC in SSIS 2012

    - by jamiet
    In August 2011 the SQL Server client team published a blog post entitled Microsoft is Aligning with ODBC for Native Relational Data Access in which they basically said "OLE DB is the past, ODBC is the future. Deal with it.". From that blog post:We encourage you to adopt ODBC in the development of your new and future versions of your application. You don’t need to change your existing applications using OLE DB, as they will continue to be supported on Denali throughout its lifecycle. While this gives you a large window of opportunity for changing your applications before the deprecation goes into effect, you may want to consider migrating those applications to ODBC as a part of your future roadmap.I recently undertook a project using SSIS2012 and heeded that advice by opting to use ODBC Connection Managers rather than OLE DB Connection Managers. Unfortunately my finding was that the ODBC Connection Manager is not yet ready for primetime use in SSIS 2012. The main issue I found was that you can't populate an Object variable with a recordset when using an Execute SQL Task connecting to an ODBC data source; any attempt to do so will result in an error:"Disconnected recordsets are not available from ODBC connections." I have filed a bug on Connect at ODBC Connection Manager does not have same funcitonality as OLE DB. For this reason I strongly recommend that you don't make the move to ODBC Connection Managers in SSIS just yet - best to wait for the next version of SSIS before doing that.I found another couple of issues with the ODBC Connection Manager that are worth keeping in mind:It doesn't recognise System Data Source Names (DSNs), only User DSNs (bug filed at ODBC System DSNs are not available in the ODBC Connection Manager)  UPDATE: According to a comment on that Connect item this may only be a problem on 64bit.In the OLE DB Connection Manager parameter ordinals are 0-based, in the ODBC Connection Manager they are 1-based (oh I just can't wait for the upgrade mess that ensues from this one!!!)You have been warned!@jamiet

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  • "Can't open display" even after access with xhost

    - by Yann
    I'm trying to run a graphical program remotely, without using ssh. I've set the display variable on the server (let's say server.com, Linux, not ubuntu, and no su rights) to point to my workstation (workstation.com, ubuntu 10.04) setenv DISPLAY workstation.com:0 Then on my workstation I've tried both xhost +server.com and xhost + Then I ssh into the server (to test things): ssh [email protected] and try to run xclock, and get the following error: Error: Can't open display: workstation.com:0 I've looked at /etc/ssh/ssh_config on the workstation and I should be forwarding correctly: X11Forwarding yes. How do I go about troubleshooting this? What logs on the workstation document these failed attempts? To explain why I'm doing this: I want to run a batch job on a server to debug an MPI-based parallel program. I want to run xterm as the batch job executable, per the instructions provided by the system admins. This setup use to work. I reinstalled things on my workstation and since then I frequently get one-time message along the lines The authenticity of host 'hostname (XXX.XXX.XXX.XX)' can't be established. My attempt to fix the above was to move my ~/.ssh/known_hosts file to a back up on both server and host, and then to ssh from each to the other with the flag -o StrictHostKeyChecking=no. I no longer get that message, but I was wondering does this play a part in why X11 forwarding is not working?

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  • Most efficient Implementation a Tree in C++

    - by Topo
    I need to write a tree where each element may have any number of child elements, and because of this each branch of the tree may have any length. The tree is only going to receive elements at first and then it is going to use exclusively for iterating though it's branches in no specific order. The tree will have several million elements and must be fast but also memory efficient. My plan makes a node class to store the elements and the pointers to its children. When the tree is fully constructed, it would be transformed it to an array or something faster and if possible, loaded to the processor's cache. Construction and the search on the tree are two different problems. Can I focus on how to solve each problem on the best way individually? The construction of has to be as fast as possible but it can use memory as it pleases. Then the transformation into a format that give us speed when iterating the tree's branches. This should preferably be an array to avoid going back and forth from RAM to cache in each element of the tree. So the real question is which is the structure to implement a tree to maximize insert speed, how can I transform it to a structure that gives me the best speed and memory?

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  • Whats a good way to do Collision with 2D Rectangles? can someone give me a tip?

    - by Javier
    using System; using System.Collections.Generic; using System.Linq; using System.Text; using Microsoft.Xna.Framework; namespace BreakOut { class Field { public static Field generateField() { List<Block> blocks = new List<Block>(); for (int j = 0; j < BlockType.BLOCK_TYPES.Length; j++) for (int i = 0; i < (Game1.WIDTH / Block.WIDTH); i++) { Block b = new Block(BlockType.BLOCK_TYPES[j], new Vector2(i * Block.WIDTH, (Block.HEIGHT + 2) * j + 5)); blocks.Add(b); } return new Field(blocks); } List<Block> blocks; public Field(List<Block> blocks) { this.blocks = blocks; } public void Update(GameTime gameTime, Ball b) { List<Block> removals = new List<Block>(); foreach (Block o in blocks) { if (o.BoundingBox.Intersects(new Rectangle((int)b.pos.X, (int)b.pos.Y, Ball.WIDTH, Ball.HEIGHT))) //collision with blocks { removals.Add(o); } } foreach(Block o in removals) blocks.Remove(o); //removes the blocks, but i need help hitting one at a time } public void Draw(GameTime gameTime) { foreach (Block b in blocks) b.Draw(gameTime); } } } My problem is that My collision in this sucks. I'm trying to add collision with a ball and hitting against a block and then one of the blocks dissapear. The problem i'm having is: When the ball hits the block, it removes it all in one instance. Please people don't be mean and say mean answers to me, im just in highschool, still a nooby and trying to learn more c#/XNA..

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  • Algorithm for rating books: Relative perception

    - by suneet
    So I am developing this application for rating books (think like IMDB for books) using relational database. Problem statement : Let's say book "A" deserves 8.5 in absolute sense. In case if A is the best book I have ever seen, I'll most probably rate it 9.5 whereas for someone else, it might be just an average book, so he/they will rate it less (say around 8). Let's assume 4 such guys rate it 8. If there are 10 guys who are like me (who haven't ever read great literature) and they all rate it 9.5-10. This will effectively make it's cumulative rating greater than 9 (9.5*10 + 8*4) / 14 = 9.1 whereas we needed the result to be 8.5 ... How can I take care of(normalize) this bias due to incorrect perception of individuals. MyProposedSolution : Here's one of the ways how I think it could be solved. We can have a variable Lit_coefficient which tells us how much knowledge a user has about literature. If I rate "A"(the book) 9.5 and person "X" rates it 8, then he must have read books much better than "A" and thus his Lit_coefficient should be higher. And then we can normalize the ratings according to the Lit_coefficient of user. Could there be a better algorithm/solution for the same?

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