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  • Problem animating in Unity/Orthello 2D. Can't move gameObject

    - by Nelson Gregório
    I have a enemy npc that moves left and right in a corridor. It's animated with 2 sprites using Orthello 2D Framework. If I untick the animation's play on start and looping, the npc moves correctly. If I turn it on, the npc tries to move but is pulled back to his starting position again and again because of the animation loop. If I turn looping off during runtime, the npc moves correctly again. What did I do wrong? Here's the npc code if needed. using UnityEngine; using System.Collections; public class Enemies : MonoBehaviour { private Vector2 movement; public float moveSpeed = 200; public bool started = true; public bool blockedRight = false; public bool blockedLeft = false; public GameObject BorderL; public GameObject BorderR; void Update () { if (gameObject.transform.position.x < BorderL.transform.position.x) { started = false; blockedRight = false; blockedLeft = true; } if (gameObject.transform.position.x > BorderR.transform.position.x) { started = false; blockedLeft = false; blockedRight = true; } if(started) { movement = new Vector2(1, 0f); movement *= Time.deltaTime*moveSpeed; gameObject.transform.Translate(movement.x,movement.y, 0f); } if(!blockedRight && !started && blockedLeft) { movement = new Vector2(1, 0f); movement *= Time.deltaTime*moveSpeed; gameObject.transform.Translate(movement.x,movement.y, 0f); } if(!blockedLeft && !started && blockedRight) { movement = new Vector2(-1, 0f); movement *= Time.deltaTime*moveSpeed; gameObject.transform.Translate(movement.x,movement.y, 0f); } } }

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  • Why do "Joke" programming languages exist? [closed]

    - by ThePlan
    First of all please be aware this post contains some abusive language but I hope it will not bother anyone. I apologize for the bad language but that's what the name is. As I've been doing documentation on existing programming languages attempting to make a complete list of them I stumbled across terrible programming languages, which were clearly not made for actual use and implementation due to their insane difficulty. Languages such as Brainfu*k and LOLCODE or Whitespace are fool languages because they have no real use. For example, a "Hello world" program written in BrainFu*k. Taken from Wikipedia: The following program prints "Hello World!" and a newline to the screen: +++++ +++++ initialize counter (cell #0) to 10 [ use loop to set the next four cells to 70/100/30/10 > +++++ ++ add 7 to cell #1 > +++++ +++++ add 10 to cell #2 > +++ add 3 to cell #3 > + add 1 to cell #4 <<<< - decrement counter (cell #0) ] > ++ . print 'H' > + . print 'e' +++++ ++ . print 'l' . print 'l' +++ . print 'o' > ++ . print ' ' << +++++ +++++ +++++ . print 'W' > . print 'o' +++ . print 'r' ----- - . print 'l' ----- --- . print 'd' > + . print '!' > . print '\n' or another example taken from LOLCODE language: HAI CAN HAS STDIO? PLZ OPEN FILE "LOLCATS.TXT"? AWSUM THX VISIBLE FILE O NOES INVISIBLE "ERROR!" KTHXBYE These languages are very difficult to learn/read/work with. My question is - Why do they exist? What is the purpose of them? Also, is there an official "name" for these type of languages?

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  • How can I clear explosions in my function?

    - by hustlerinc
    Hi I have a function to place bombs, and a for loop that places explosions on the tiles where possible. My problem is that I can't remove the explosions after a while. I've tried everything I can come up with so now I turn here as a last resort. The function looks like this: function Bomb(){ var placebomb = false; if(placeBomb && player.bombs != 0){ map[player.Y][player.X].object = 2; var bombX = player.X; var bombY = player.Y; placeBomb = false; player.bombs--; setTimeout(explode, 3000); } function explode(){ var explodeNorth = true; var explodeEast = true; var explodeSouth = true; var explodeWest = true; map[bombY][bombX].explosion = 1; delete map[bombY][bombX].object; for(i=0;i<=player.bombRadius;i++){ if(explodeNorth && map[bombY-i][bombX]){ if(!map[bombY-i][bombX].wall){ if(!map[bombY-i][bombX].object){ map[bombY-i][bombX].explosion = 1; } else var explodeNorth = false; delete map[bombY-i][bombX].object; map[bombY-i][bombX].explosion = 1; } else var explodeNorth = false; } if(explodeEast && map[bombY][bombX+i]){ if(!map[bombY][bombX+i].wall){ if(!map[bombY][bombX+i].object){ map[bombY][bombX+i].explosion = 1; } else var explodeEast = false; delete map[bombY][bombX+i].object; map[bombY][bombX+i].explosion = 1; } else var explodeEast = false; } if(explodeSouth && map[bombY+i][bombX]){ if(!map[bombY+i][bombX].wall){ if(!map[bombY+i][bombX].object){ map[bombY+i][bombX].explosion = 1; } else var explodeSouth = false; delete map[bombY+i][bombX].object; map[bombY+i][bombX].explosion = 1; } else var explodeSouth = false; } if(explodeWest && map[bombY][bombX-i]){ if(!map[bombY][bombX-i].wall){ if(!map[bombY][bombX-i].object){ map[bombY][bombX-i].explosion = 1; } else var explodeWest = false; delete map[bombY][bombX-i].object; map[bombY][bombX-i].explosion = 1; } else var explodeWest = false; } } player.bombs++; } } If anyone can think of a good way to remove the explosion after a delay please help.

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  • Nifty popup fails to register

    - by Snailer
    I'm new to Nifty GUI, so I'm following a tutorial here for making popups. For now, I'm just trying to get a very basic "test" popup to show, but I get multiple errors and none of them make much sense. To show a popup, I believe it is necessary to first have a Nifty Screen already showing, which I do. So here is the ScreenController for the working Nifty Screen: public class WorkingScreen extends AbstractAppState implements ScreenController { //Main is my jme SimpleApplication private Main app; private Nifty nifty; private Screen screen; public WorkingScreen() {} public void equip(String slotstr) { int slot = Integer.valueOf(slotstr); System.out.println("Equipping item in slot "+slot); //Here's where it STOPS working. app.getPlayer().registerPopupScreen(nifty); System.out.println("Registered new popup"); Element ele = nifty.createPopup(app.getPlayer().POPUP); System.out.println("popup is " +ele); nifty.showPopup(nifty.getCurrentScreen(), ele.getId(), null); } @Override public void initialize(AppStateManager stateManager, Application app) { super.initialize(stateManager, app); this.app = (Main)app; } @Override public void update(float tpf) { /** jME update loop! */ } public void bind(Nifty nifty, Screen screen) { this.nifty = nifty; this.screen = screen; } When I call equip(0) the system prints Equipping item in slot 0, then a lot of errors and none of the subsequent println()'s. Clearly it botches somewhere in Player.registerPopupScreen(Nifty nifty). Here's the method: public final String POPUP = "Test Popup"; public void registerPopupScreen(Nifty nifty) { System.out.println("Attempting new popup"); PopupBuilder b = new PopupBuilder(POPUP) {{ childLayoutCenter(); backgroundColor("#000a"); panel(new PanelBuilder() {{ id("List"); childLayoutCenter(); height(percentage(75)); width(percentage(50)); control(new ButtonBuilder("TestButton") {{ label("TestButton"); width("120px"); height("40px"); align(Align.Center); }}); }}); }}; System.out.println("PopupBuilder success."); b.registerPopup(nifty); System.out.println("Registerpopup success."); } Because that first println() doesn't show, it looks like this method isn't even called at all! Edit After removing all calls on the Player object, the popup works. It seems I'm not "allowed" to access the player from the ScreenController. Unfortunate, since I need information on the player for the popup. Is there a workaround?

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  • Small script to look for Project Replication actions that have failed

    - by Trond Strømme
    Today when looking at a couple of projects on a ZFS 7320 Storage Appliance I noticed on one project that one of its replication actions had failed, as I hadn't checked the Recent Alerts log yet I was not aware of this. I decided to write a small script to check if there were others that had failed. Nothing fancy, just a loop through all projects, look at the project's replication child and compare the values of the last_sync and last_try properties and print the result if they're not equal. (There are probably more sensible ways of doing this, but at least it involves me getting the chance to put on my headphones and doing just a little bit of coding.) script // this script will locate failed project level replication // it will look at the sync times for 'last_sync' and 'last_try' // and compare these, if they deviate you should investigate. // NOTE! this code is offered 'as is' Run at your own risk, // it will probably work as intended, but in now way can I // (or Oracle) be held responsible if your server starts behaving // like a three year old kid in a candy store.. (not that mine do, // they are very well behaved boys...) run('configuration'); run('storage'); printf('Host: %s, pool: %s\n', get('owner'),get('pool')); run('cd /'); run('shares'); proj=list(); printf("total projects: %d\n",proj.length +'\n'); // just for project level replication for(i=0;i<proj.length;i++){ run('select '+proj[i]); run('replication'); //get all replication actions preps = list(); for(j=0;j<preps.length;j++){ run('select ' + preps[j]); last_sync = get('last_sync'); last_try = get('last_try'); // printf("target %s\n", get('target')); //why the flip does this not get the proper name? if(!( last_sync.valueOf() === last_try.valueOf())){ printf("sync has failed for %s %s\n", proj[i], get('target')); }else{ // printf("OK %s %s\n", proj[i], get('target')); } run('done'); //done with the replica action } run('done'); run('done'); } printf("finished\n"); For a more on how to run the script, or testing it please look at my previous post. Sample output: Host: elb1sn01, pool: exalogic total projects: 45 sync has failed for ACSExalogicSystem cb3a24fe-ad60-c90f-d15d-adaafd595639 finished

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  • Single use download script - Modification [on hold]

    - by Iulius
    I have this Single use download script! This contain 3 php files: page.php , generate.php and variables.php. Page.php Code: <?php include("variables.php"); $key = trim($_SERVER['QUERY_STRING']); $keys = file('keys/keys'); $match = false; foreach($keys as &$one) { if(rtrim($one)==$key) { $match = true; $one = ''; } } file_put_contents('keys/keys',$keys); if($match !== false) { $contenttype = CONTENT_TYPE; $filename = SUGGESTED_FILENAME; readfile(PROTECTED_DOWNLOAD); exit; } else { ?> <html> <head> <meta http-equiv="refresh" content="1; url=http://docs.google.com/"> <title>Loading, please wait ...</title> </head> <body> Loading, please wait ... </body> </html> <?php } ?> Generate.php Code: <?php include("variables.php"); $password = trim($_SERVER['QUERY_STRING']); if($password == ADMIN_PASSWORD) { $new = uniqid('key',TRUE); if(!is_dir('keys')) { mkdir('keys'); $file = fopen('keys/.htaccess','w'); fwrite($file,"Order allow,deny\nDeny from all"); fclose($file); } $file = fopen('keys/keys','a'); fwrite($file,"{$new}\n"); fclose($file); ?> <html> <head> <title>Page created</title> <style> nl { font-family: monospace } </style> </head> <body> <h1>Page key created</h1> Your new single-use page link:<br> <nl> <?php echo "http://" . $_SERVER['HTTP_HOST'] . DOWNLOAD_PATH . "?" . $new; ?></nl> </body> </html> <?php } else { header("HTTP/1.0 404 Not Found"); } ?> And the last one Variables.php Code: <? define('PROTECTED_DOWNLOAD','download.php'); define('DOWNLOAD_PATH','/.work/page.php'); define('SUGGESTED_FILENAME','download-doc.php'); define('ADMIN_PASSWORD','1234'); define('EXPIRATION_DATE', '+36 hours'); header("Cache-Control: no-cache, must-revalidate"); header("Expires: ".date('U', strtotime(EXPIRATION_DATE))); ?> The http://www.site.com/generate.php?1234 will generate a unique link like page.php?key1234567890. This link page.php?key1234567890 will be sent by email to my user. Now how can I generate a link like this page.php?key1234567890&[email protected] ? So I think I must access the generator page like this generate.php?1234&[email protected] . P.S. This variable will be posted on the download page by "Hello, " I tried everthing to complete this, and no luck. Thanks in advance for help.

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  • How should I structure my turn based engine to allow flexibility for players/AI and observation?

    - by Reefpirate
    I've just started making a Turn Based Strategy engine in GameMaker's GML language... And I was cruising along nicely until it came time to handle the turn cycle, and determining who is controlling what player, and also how to handle the camera and what is displayed on screen. Here's an outline of the main switch happening in my main game loop at the moment: switch (GameState) { case BEGIN_TURN: // Start of turn operations/routines break; case MID_TURN: switch (PControlledBy[Turn]) { case HUMAN: switch (MidTurnState) { case MT_SELECT: // No units selected, 'idle' UI state break; case MT_MOVE: // Unit selected and attempting to move break; case MT_ATTACK: break; } break; case COMPUTER: // AI ROUTINES GO HERE break; case OBSERVER: // OBSERVER ROUTINES GO HERE break; } break; case END_TURN: // End of turn routines/operations, and move Turn to next player break; } Now, I can see a couple of problems with this set-up already... But I don't have any idea how to go about making it 'right'. Turn is a global variable that stores which player's turn it is, and the BEGIN_TURN and END_TURN states make perfect sense to me... But the MID_TURN state is baffling me because of the things I want to happen here: If there are players controlled by humans, I want the AI to do it's thing on its turn here, but I want to be able to have the camera follow the AI as it makes moves in the human player's vision. If there are no human controlled player's, I'd like to be able to watch two or more AI's battle it out on the map with god-like 'observer' vision. So basically I'm wondering if there are any resources for how to structure a Turn Based Strategy engine? I've found lots of writing about pathfinding and AI, and those are all great... But when it comes to handling the turn structure and the game states I am having trouble finding any resources at all. How should the states be divided to allow flexibility between the players and the controllers (HUMAN, COMPUTER, OBSERVER)? Also, maybe if I'm on the right track I just need some reassurance before I lay down another few hundred lines of code...

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  • Live-Ubuntu 12.04 ran fine, now stopped booting!

    - by user89743
    I've seen similar problems to this several times in the forum, but mine is a bit different, so the other posts I saw were no help to me. When I boot Ubuntu 12.04 64-bit from live-SD-card (3GB persistence) I suddenly get this error: (initramfs) mount: mounting /dev/loop0 on //filesystem.squashfs failed: Invalid argument Can not mount /dev/loop/0 (/cdrom/casper/filesystem.squashfs) on //filesystem.squashfs (it says I can type "help" for commands, but I don't know anything about how to go from there, totally new to linux) The reason I say my case is different is because my Ubuntu worked fine for over a week, even pretty fast, and now this problem happened. Before that I used to run my live ubuntu from USB sticks but that was slower (especially when booting which took 15 minutes from USB stick!). Also I kept getting the same above problem after a while when booting and had to re-create a live USB linux several times. Installing on harddrive is not an option because my harddrive has physical damage and getting a replacement will take a while, therefore I can only use live-USB or live-SD-card Ubuntu. As I said I used Ubuntu without problems for more than a week, before that as well for several weeks on USB sticks, but the above problem occured sooner or later. This time I paid attention to when it happened: I was rebooting my computer (HP 620 laptop, 4 GB RAM, 64 bit system) from SD flash card and when I was booting I selected F6 and then the first option "no acpi" or something like that...I had used it before and noticed it slowed down the time it took Linux to use. This time it caused this error. Now even when I boot normally/default I get this error. Now I'm accessing Ubuntu from my USB stick without persistence file, when I check my SD card, all the files mentioned in the error message are there and the filesystem.squashfs is 691.2 MB so nothing seems to have been deleted by accident. (I have already made many changes/downloaded programs to my SD card persistent Ubuntu and would hope to loose them, since downloading is expensive for me, and since the problem seems to re-occur...) Can anyone help me, preferably without having to create another startup disk on my SD card? I'm totally new to this. Sorry for the long posts, just didn't know what info is relevant and what isnt! Kon

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  • Generating tileable terrain using Perlin Noise [duplicate]

    - by terrorcell
    This question already has an answer here: How do you generate tileable Perlin noise? 9 answers I'm having trouble figuring out the solution to this particular algorithm. I'm using the Perlin Noise implementation from: https://code.google.com/p/mikeralib/source/browse/trunk/Mikera/src/main/java/mikera/math/PerlinNoise.java Here's what I have so far: for (Chunk chunk : chunks) { PerlinNoise noise = new PerlinNoise(); for (int y = 0; y < CHUNK_SIZE_HEIGHT; ++y) { for (int x = 0; x < CHUNK_SIZE_WIDTH; ++x) { int index = get1DIndex(y, CHUNK_SIZE_WIDTH, x); float val = 0; for (int i = 2; i <= 32; i *= i) { double n = noise.tileableNoise2(i * x / (float)CHUNK_SIZE_WIDTH, i * y / (float)CHUNK_SIZE_HEIGHT, CHUNK_SIZE_WIDTH, CHUNK_SIZE_HEIGHT); val += n / i; } // chunk tile at [index] gets set to the colour 'val' } } } Which produces something like this: Each chunk is made up of CHUNK_SIZE number of tiles, and each tile has a TILE_SIZE_WIDTH/HEIGHT. I think it has something to do with the inner-most for loop and the x/y co-ords given to the noise function, but I could be wrong. Solved: PerlinNoise noise = new PerlinNoise(); for (Chunk chunk : chunks) { for (int y = 0; y < CHUNK_SIZE_HEIGHT; ++y) { for (int x = 0; x < CHUNK_SIZE_WIDTH; ++x) { int index = get1DIndex(y, CHUNK_SIZE_WIDTH, x); float val = 0; float xx = x * TILE_SIZE_WIDTH + chunk.x; float yy = y * TILE_SIZE_HEIGHT + chunk.h; int w = CHUNK_SIZE_WIDTH * TILE_SIZE_WIDTH; int h = CHUNK_SIZE_HEIGHT * TILE_SIZE_HEIGHT; for (int i = 2; i <= 32; i *= i) { double n = noise.tileableNoise2(i * xx / (float)w, i * yy / (float)h, w, h); val += n / i; } // chunk tile at [index] gets set to the colour 'val' } } }

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  • Simple thruster like behaviour when rotating sprite

    - by ensamgud
    I'm prototyping some 2D game concepts with XNA and have added some basic keyboard inputs to control a triangle sprite. When I press key up the sprite accelerates in it's current facing direction, when I release the key it brakes down. For rotation, when I press left/right keys I rotate the sprite. Currently the sprite immedately changes direction when I rotate it. What I want is for it to keep moving in the same direction when I rotate, until I hit key up, adding thrust in whatever direction the sprite is pointing at. This would simulate thrusters on a classic space shooter like Asteroids. I'm adding an image to describe the behaviour I'm after and some code samples of how I'm doing things at the moment. This is my player struct, holding information of the sprite. public struct PlayerData { public Vector2 Position; // where to draw the sprite public Vector2 Direction; // travel direction of sprite public float Angle; // rotation of sprite public float Velocity; public float Acceleration; public float Decelleration; public float RotationAcceleration; public float RotationDecceleration; public float TopSpeed; public float Scale; } This is how I'm currently handling thrusting / braking (when pressing/releasing key up) (simplified, removed some bounds checking etc): player.Velocity += player.Acceleration * 0.1f; player.Velocity -= player.Acceleration * 0.1f; And when I rotate the sprite left and right: player.Angle -= player.RotationAcceleration * 0.1f; player.Angle += player.RotationAcceleration * 0.1f; This runs in the update loop, keeps the direction updated and updates the position: Vector2 up = new Vector2(0f, -1f); Matrix rotMatrix = Matrix.CreateRotationZ(player.Angle); player.Direction = Vector2.Transform(up, rotMatrix); player.Direction *= player.Velocity; player.Position += player.Direction; I am following along various beginner tutorials and haven't found any describing this, but I have tried some on my own without success. Do I need to change my velocity and acceleration fields to Vectors instead of floats to accomplish this type of movement? I realise my Angle and the Direction vector is currently tied together and I need to disconnect these somehow to be able to rotate freely without changing the direction of the movement, but I can't quite figure out how to do this while keeping the acceleration/decceleration functional. Would appreciate an explanation rather than pure code samples. Thanks,

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  • OpenGL ES 2 jittery camera movement

    - by user16547
    First of all, I am aware that there's no camera in OpenGL (ES 2), but from my understanding proper manipulation of the projection matrix can simulate the concept of a camera. What I'm trying to do is make my camera follow my character. My game is 2D, btw. I think the principle is the following (take Super Mario Bros or Doodle Jump as reference - actually I'm trying to replicate the mechanics of the latter): when the caracter goes beyond the center of the screen (in the positive axis/direction), update the camera to be centred on the character. Else keep the camera still. I did accomplish that, however the camera movement is noticeably jittery and I ran out of ideas how to make it smoother. First of all, my game loop (following this article): private int TICKS_PER_SECOND = 30; private int SKIP_TICKS = 1000 / TICKS_PER_SECOND; private int MAX_FRAMESKIP = 5; @Override public void run() { loops = 0; if(firstLoop) { nextGameTick = SystemClock.elapsedRealtime(); firstLoop = false; } while(SystemClock.elapsedRealtime() > nextGameTick && loops < MAX_FRAMESKIP) { step(); nextGameTick += SKIP_TICKS; loops++; } interpolation = ( SystemClock.elapsedRealtime() + SKIP_TICKS - nextGameTick ) / (float)SKIP_TICKS; draw(); } And the following code deals with moving the camera. I was unsure whether to place it in step() or draw(), but it doesn't make a difference to my problem at the moment, as I tried both and neither seemed to fix it. center just represents the y coordinate of the centre of the screen at any time. Initially it is 0. The camera object is my own custom "camera" which basically is a class that just manipulates the view and projection matrices. if(character.getVerticalSpeed() >= 0) { //only update camera if going up float[] projectionMatrix = camera.getProjectionMatrix(); if( character.getY() > center) { center += character.getVerticalSpeed(); cameraBottom = center + camera.getBottom(); cameraTop = center + camera.getTop(); Matrix.orthoM(projectionMatrix, 0, camera.getLeft(), camera.getRight(), center + camera.getBottom(), center + camera.getTop(), camera.getNear(), camera.getFar()); } } Any thought about what I should try or what I am doing wrong? Update 1: I think I updated every value you can see on screen to check whether the jittery movement is affected by that, but nothing changed, so something must be fundamentally flawed with my approach/calculations.

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  • Problem creating levels using inherited classes/polymorphism

    - by Adam
    I'm trying to write my level classes by having a base class that each level class inherits from...The base class uses pure virtual functions. My base class is only going to be used as a vector that'll have the inherited level classes pushed onto it...This is what my code looks like at the moment, I've tried various things and get the same result (segmentation fault). //level.h class Level { protected: Mix_Music *music; SDL_Surface *background; SDL_Surface *background2; vector<Enemy> enemy; bool loaded; int time; public: Level(); virtual ~Level(); int bgX, bgY; int bg2X, bg2Y; int width, height; virtual void load(); virtual void unload(); virtual void update(); virtual void draw(); }; //level.cpp Level::Level() { bgX = 0; bgY = 0; bg2X = 0; bg2Y = 0; width = 2048; height = 480; loaded = false; time = 0; } Level::~Level() { } //virtual functions are empty... I'm not sure exactly what I'm supposed to include in the inherited class structure, but this is what I have at the moment... //level1.h class Level1: public Level { public: Level1(); ~Level1(); void load(); void unload(); void update(); void draw(); }; //level1.cpp Level1::Level1() { } Level1::~Level1() { enemy.clear(); Mix_FreeMusic(music); SDL_FreeSurface(background); SDL_FreeSurface(background2); music = NULL; background = NULL; background2 = NULL; Mix_CloseAudio(); } void Level1::load() { music = Mix_LoadMUS("music/song1.xm"); background = loadImage("image/background.png"); background2 = loadImage("image/background2.png"); Mix_OpenAudio(48000, MIX_DEFAULT_FORMAT, 2, 4096); Mix_PlayMusic(music, -1); } void Level1::unload() { } //functions have level-specific code in them... Right now for testing purposes, I just have the main loop call Level1 level1; and use the functions, but when I run the game I get a segmentation fault. This is the first time I've tried writing inherited classes, so I know I'm doing something wrong, but I can't seem to figure out what exactly.

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  • Problem trying to lock framerate at 60 FPS

    - by shad0w
    I've written a simple class to limit the framerate of my current project. But it does not work as it should. Here is the code: void FpsCounter::Process() { deltaTime = static_cast<double>(frameTimer.GetMsecs()); waitTime = 1000.0/fpsLimit - deltaTime; frameTimer.Reset(); if(waitTime <= 0) { std::cout << "error, waittime: " << waitTime << std::endl; } else { SDL_Delay(static_cast<Uint32>(waitTime)); } if(deltaTime == 0) { currFps = -1; } else { currFps = 1000/deltaTime; } std::cout << "--Timings--" << std::endl; std::cout << "Delta: \t" << deltaTime << std::endl; std::cout << "Delay: \t" << waitTime << std::endl; std::cout << "FPS: \t" << currFps << std::endl; std::cout << "-- --" << std::endl; } Timer::Timer() { startMsecs = 0; } Timer::~Timer() { // TODO Auto-generated destructor stub } void Timer::Start() { started = true; paused = false; Reset(); } void Timer::Pause() { if(started && !paused) { paused = true; pausedMsecs = SDL_GetTicks() - startMsecs; } } void Timer::Resume() { if(paused) { paused = false; startMsecs = SDL_GetTicks() - pausedMsecs; pausedMsecs = 0; } } int Timer::GetMsecs() { if(started) { if(paused) { return pausedMsecs; } else { return SDL_GetTicks() - startMsecs; } } return 0; } void Timer::Reset() { startMsecs = SDL_GetTicks(); } The "FpsCounter::Process()" Method is called everytime at the end of my gameloop. I've got the problem that the loop is correctly delayed only every second frame, so it runs one frame delayed at 60 FPS and the next without delay at over 1000 fps. I am searching the error quite a while now, but I do not find it. I hope somebody can point me in the right direction.

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  • Why is this beat detection code failing to register some beats properly?

    - by Quincy
    I made this SoundAnalyzer class to detect beats in songs: class SoundAnalyzer { public SoundBuffer soundData; public Sound sound; public List<double> beatMarkers = new List<double>(); public SoundAnalyzer(string path) { soundData = new SoundBuffer(path); sound = new Sound(soundData); } // C = threshold, N = size of history buffer / 1024 B = bands public void PlaceBeatMarkers(float C, int N, int B) { List<double>[] instantEnergyList = new List<double>[B]; GetEnergyList(B, ref instantEnergyList); for (int i = 0; i < B; i++) { PlaceMarkers(instantEnergyList[i], N, C); } beatMarkers.Sort(); } private short[] getRange(int begin, int end, short[] array) { short[] result = new short[end - begin]; for (int i = 0; i < end - begin; i++) { result[i] = array[begin + i]; } return result; } // get a array of with a list of energy for each band private void GetEnergyList(int B, ref List<double>[] instantEnergyList) { for (int i = 0; i < B; i++) { instantEnergyList[i] = new List<double>(); } short[] samples = soundData.Samples; float timePerSample = 1 / (float)soundData.SampleRate; int sampleIndex = 0; int nextSamples = 1024; int samplesPerBand = nextSamples / B; // for the whole song while (sampleIndex + nextSamples < samples.Length) { complex[] FFT = FastFourier.Calculate(getRange(sampleIndex, nextSamples + sampleIndex, samples)); // foreach band for (int i = 0; i < B; i++) { double energy = 0; for (int j = 0; j < samplesPerBand; j++) energy += FFT[i * samplesPerBand + j].GetMagnitude(); energy /= samplesPerBand; instantEnergyList[i].Add(energy); } if (sampleIndex + nextSamples >= samples.Length) nextSamples = samples.Length - sampleIndex - 1; sampleIndex += nextSamples; samplesPerBand = nextSamples / B; } } // place the actual markers private void PlaceMarkers(List<double> instantEnergyList, int N, float C) { double timePerSample = 1 / (double)soundData.SampleRate; int index = N; int numInBuffer = index; double historyBuffer = 0; //Fill the history buffer with n * instant energy for (int i = 0; i < index; i++) { historyBuffer += instantEnergyList[i]; } // If instantEnergy / samples in buffer < instantEnergy for the next sample then add beatmarker. while (index + 1 < instantEnergyList.Count) { if(instantEnergyList[index + 1] > (historyBuffer / numInBuffer) * C) beatMarkers.Add((index + 1) * 1024 * timePerSample); historyBuffer -= instantEnergyList[index - numInBuffer]; historyBuffer += instantEnergyList[index + 1]; index++; } } } For some reason it's only detecting beats from 637 sec to around 641 sec, and I have no idea why. I know the beats are being inserted from multiple bands since I am finding duplicates, and it seems that it's assigning a beat to each instant energy value in between those values. It's modeled after this: http://www.flipcode.com/misc/BeatDetectionAlgorithms.pdf So why won't the beats register properly?

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  • Create simple jQuery plugin

    - by ybbest
    In the last post, I have shown you how to add the function to jQuery. In this post, I will show you how to create plugin to achieve this. 1. You need to wrap your code in the following construct, this is because you should not use $ directly as $ is global variable, it could have clash with some other library which also use $.Basically, you can pass in jQuery object into the function, so that $ is made available inside the function. (JavaScript use function to create scope, so you can make sure $ is referred to jQuery inside the function ) (function($){ //Your code goes here. }; })(jQuery); 2. Put your code into the construct above. (function ($) { $.getParameterByName = function (name) { name = name.replace(/[\[]/, "\\\[").replace(/[\]]/, "\\\]"); var regexS = "[\\?&]" + name + "=([^&#]*)"; var regex = new RegExp(regexS); var results = regex.exec(window.location.search); if (results == null) return ""; else return decodeURIComponent(results[1].replace(/\+/g, " ")); }; })(jQuery); 3. Now you can reference the code into you project and you can call the method in you JavaScript References: Provides scope for variables Variables are scoped at the function level in javascript. This is different to what you might be used to in a language like C# or Java where the variables are scoped to the block. What this means is if you declare a variable inside a loop or an if statement, it will be available to the entire function. If you ever find yourself needing to explicitly scope a variable inside a function you can use an anonymous function to do this. You can actually create an anonymous function and then execute it straight away and all the variables inside will be scoped to the anonymous function: (function() { var myProperty = "hello world"; alert(myProperty); })(); alert(typeof(myProperty)); // undefined How does an anonymous function in JavaScript work? Building Your First jQuery Plugin A Plugin Development Pattern

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  • How do you make a bullet ricochet off a vertical wall?

    - by Bagofsheep
    First things first. I am using C# with XNA. My game is top-down and the player can shoot bullets. I've managed to get the bullets to ricochet correctly off horizontal walls. Yet, despite using similar methods (e.g. http://stackoverflow.com/questions/3203952/mirroring-an-angle) and reading other answered questions about this subject I have not been able to get the bullets to ricochet off a vertical wall correctly. Any method I've tried has failed and sometimes made ricocheting off a horizontal wall buggy. Here is the collision code that calls the ricochet method: //Loop through returned tile rectangles from quad tree to test for wall collision. If a collision occurs perform collision logic. for (int r = 0; r < returnObjects.Count; r++) if (Bullets[i].BoundingRectangle.Intersects(returnObjects[r])) Bullets[i].doCollision(returnObjects[r]); Now here is the code for the doCollision method. public void doCollision(Rectangle surface) { if (Ricochet) doRicochet(surface); else Trash = true; } Finally, here is the code for the doRicochet method. public void doRicochet(Rectangle surface) { if (Position.X > surface.Left && Position.X < surface.Right) { //Mirror the bullet's angle. Rotation = -1 * Rotation; //Moves the bullet in the direction of its rotation by given amount. moveFaceDirection(Sprite.Width * BulletScale.X); } else if (Position.Y > surface.Top && Position.Y < surface.Bottom) { } } Since I am only dealing with vertical and horizontal walls at the moment, the if statements simply determine if the object is colliding from the right or left, or from the top or bottom. If the object's X position is within the boundaries of the tile's X boundaries (left and right sides), it must be colliding from the top, and vice verse. As you can see, the else if statement is empty and is where the correct code needs to go.

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  • PASS: FY10 Actuals Posted

    - by Bill Graziano
    Earlier this year we published preliminary fiscal year 2010 financials to the Governance page on the PASS web site.  Please remember that FY10 runs from July 1st, 2009 through June 30th, 2010 and includes the November 2009 Summit.  We do our fiscal year this way so that the Summit falls earlier in the fiscal year.  The financials we had posted were P&L numbers at the portfolio level.  Prior to this we had posted our detailed budget but only posted the auditors report at the end of each year.  Today we updated our published financials to include: Pre-audit actuals from FY10 at the same level as our budget.  The document has both actuals and budget for FY10 side by side.  This is over 20 pages of detailed financial information covering hundreds of line-items. A letter describing key differences between our budget and actuals.  I walked through each line item where the difference was greater than $25,000 and explained what happened and why. We updated the financial graph going back to 2003 to include FY10. This update should “close the loop” on our financials.  You can now start with the published budget and compare it to the finished financials at the same level of detail.  We also plan to publish the auditor’s report when that is completed -- as we do every year. Overall I’m very happy with how FY10 turned out.  Keep in mind that this was the November 2009 Summit so we were still facing economic challenges.  With all that we were roughly break-even showing a $15,000 profit on $3.9 million of revenue.  I didn’t find anything shocking in reviewing our actual vs. budget but there were a few things that needed explanation.  You can see those in the letter on the governance page. Please keep in mind that these are the actuals from our operating financials.  The auditor may have us make adjustments for depreciation or other financial transactions.  We may also account for certain transactions differently for tax purposes than we do for financial reporting purposes.  I feel these financial statements give you the clearest picture of how our organization spends its money. We were late publishing these this year.  We were working through some tax issues and that delayed our ability to file our final tax forms which delayed this process.  In hindsight I should have published these documents as soon as we had them and not waited for the tax issues.  We’ll do this better in the future. And on a final note, you don’t need to login to view these documents.  If you have any questions you can post them here.  If we get more than a few questions we may see about creating some forums for financial issues on the PASS web site.

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  • Android - Force Close - Null Pointer on Canvas?

    - by user22241
    Please bear with me. I have a very odd problem. Basically, my app so far, has 3 activities (a main splash screen, an 'options/menu' screen and the main app). If I follow the very specific steps oulined below, I get a 'null pointer exception' in the 2nd activity) and the app force closes...... Here are the steps: Start the app (a game based on Surfaceview), tap through to the third activity so the game is running, then hit the home key so the game is paused and put to the background, the activity/app is ended through DDMS in the SDK then restarted on the device (all OK so far), now if I hit the back key on the device twice in quick succession, it happens. All other sequence of events is fine, even to the point of pressing the back key, waiting for the previous activity to show, then hitting back again - all OK. Only when the back key is pressed twice in quick succession following all the above steps does the problem occur. I'm assuming that the canvas isn't ready as it's showing as 'null' when this happens, but I'm not sure why this is happening as surely it's happening when I'm trying to go back to activity 1, but the logcat shows the error in activity 2. if I stop the activity running my 'doDraw' method (which referenced the canvas), then all is OK - so I can safely assume it is the canvas causing the problem. Also, if I skip my first activity (which is a very basic full-screen button which just displays a splashscreen and waits for the user to tap the screen), and make my 2nd activity the launch activity, again, it is OK. this is the part of the code that I think is probably relevant: @Override public void surfaceChanged(SurfaceHolder arg0, int arg1, int arg2, int arg3) { vheight = this.getHeight(); vwidth = this.getWidth(); } @Override public void surfaceCreated(SurfaceHolder holder) { vheight = this.getHeight(); vwidth = this.getWidth(); this.viewWidth = vwidth; this.viewHeight = vheight; if (runthread==false){ if (preThread.getState()==Thread.State.TERMINATED){ preThread = new OptionsThread(thisholder, thiscontext, thishandler); } preThread.setRunning(true); preThread.start();} } @Override public void surfaceDestroyed(SurfaceHolder holder) { preThread.setRunning(false); //Stop the loop boolean retry = true; //Stop the thread while (retry) { try { preThread.join(); retry = false; } catch (InterruptedException e) { } } Thank you all for any help you can offer

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  • Asynchronously returning a hierarchal data using .NET TPL... what should my return object "look" like?

    - by makerofthings7
    I want to use the .NET TPL to asynchronously do a DIR /S and search each subdirectory on a hard drive, and want to search for a word in each file... what should my API look like? In this scenario I know that each sub directory will have 0..10000 files or 0...10000 directories. I know the tree is unbalanced and want to return data (in relation to its position in the hierarchy) as soon as it's available. I am interested in getting data as quickly as possible, but also want to update that result if "better" data is found (better means closer to the root of c:) I may also be interested in finding all matches in relation to its position in the hierarchy. (akin to a report) Question: How should I return data to my caller? My first guess is that I think I need a shared object that will maintain the current "status" of the traversal (started | notstarted | complete ) , and might base it on the System.Collections.Concurrent. Another idea that I'm considering is the consumer/producer pattern (which ConcurrentCollections can handle) however I'm not sure what the objects "look" like. Optional Logical Constraint: The API doesn't have to address this, but in my "real world" design, if a directory has files, then only one file will ever contain the word I'm looking for.  If someone were to literally do a DIR /S as described above then they would need to account for more than one matching file per subdirectory. More information : I'm using Azure Tables to store a hierarchy of data using these TPL extension methods. A "node" is a table. Not only does each node in the hierarchy have a relation to any number of nodes, but it's possible for each node to have a reciprocal link back to any other node. This may have issues with recursion but I'm addressing that with a shared object in my recursion loop. Note that each "node" also has the ability to store local data unique to that node. It is this information that I'm searching for. In other words, I'm searching for a specific fixed RowKey in a hierarchy of nodes. When I search for the fixed RowKey in the hierarchy I'm interested in getting the results FAST (first node found) but prefer data that is "closer" to the starting point of the hierarchy. Since many nodes may have the particular RowKey I'm interested in, sometimes I may want to get a report of ALL the nodes that contain this RowKey.

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  • Separating logic and data in browser game

    - by Tesserex
    I've been thinking this over for days and I'm still not sure what to do. I'm trying to refactor a combat system in PHP (...sorry.) Here's what exists so far: There are two (so far) types of entities that can participate in combat. Let's just call them players and NPCs. Their data is already written pretty well. When involved in combat, these entities are wrapped with another object in the DB called a Combatant, which gives them information about the particular fight. They can be involved in multiple combats at once. I'm trying to write the logic engine for combat by having combatants injected into it. I want to be able to mock everything for testing. In order to separate logic and data, I want to have two interfaces / base classes, one being ICombatantData and the other ICombatantLogic. The two implementers of data will be one for the real objects stored in the database, and the other for my mock objects. I'm now running into uncertainties with designing the logic side of things. I can have one implementer for each of players and NPCs, but then I have an issue. A combatant needs to be able to return the entity that it wraps. Should this getter method be part of logic or data? I feel strongly that it should be in data, because the logic part is used for executing combat, and won't be available if someone is just looking up information about an upcoming fight. But the data classes only separate mock from DB, not player from NPC. If I try having two child classes of the DB data implementer, one for each entity type, then how do I architect that while keeping my mocks in the loop? Do I need some third interface like IEntityProvider that I inject into the data classes? Also with some of the ideas I've been considering, I feel like I'll have to put checks in place to make sure you don't mismatch things, like making the logic for an NPC accidentally wrap the data for a player. Does that make any sense? Is that a situation that would even be possible if the architecture is correct, or would the right design prohibit that completely so I don't need to check for it? If someone could help me just layout a class diagram or something for this it would help me a lot. Thanks. edit Also useful to note, the mock data class doesn't really need the Entity, since I'll just be specifying all the parameters like combat stats directly instead. So maybe that will affect the correct design.

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  • How can I cleanly and elegantly handle data and dependancies between classes

    - by Neophyte
    I'm working on 2d topdown game in SFML 2, and need to find an elegant way in which everything will work and fit together. Allow me to explain. I have a number of classes that inherit from an abstract base that provides a draw method and an update method to all the classes. In the game loop, I call update and then draw on each class, I imagine this is a pretty common approach. I have classes for tiles, collisions, the player and a resource manager that contains all the tiles/images/textures. Due to the way input works in SFML I decided to have each class handle input (if required) in its update call. Up until now I have been passing in dependencies as needed, for example, in the player class when a movement key is pressed, I call a method on the collision class to check if the position the player wants to move to will be a collision, and only move the player if there is no collision. This works fine for the most part, but I believe it can be done better, I'm just not sure how. I now have more complex things I need to implement, eg: a player is able to walk up to an object on the ground, press a key to pick it up/loot it and it will then show up in inventory. This means that a few things need to happen: Check if the player is in range of a lootable item on keypress, else do not proceed. Find the item. Update the sprite texture on the item from its default texture to a "looted" texture. Update the collision for the item: it might have changed shape or been removed completely. Inventory needs to be updated with the added item. How do I make everything communicate? With my current system I will end up with my classes going out of scope, and method calls to each other all over the place. I could tie up all the classes in one big manager and give each one a reference to the parent manager class, but this seems only slightly better. Any help/advice would be greatly appreciated! If anything is unclear, I'm happy to expand on things.

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  • Problem with sprite direction and rotation

    - by user2236165
    I have a sprite called Tool that moves with a speed represented as a float and in a direction represented as a Vector2. When I click the mouse on the screen the sprite change its direction and starts to move towards the mouseclick. In addition to that I rotate the sprite so that it is facing in the direction it is heading. However, when I add a camera that is suppose to follow the sprite so that the sprite is always centered on the screen, the sprite won't move in the given direction and the rotation isn't accurate anymore. This only happens when I add the Camera.View in the spriteBatch.Begin(). I was hoping anyone could maybe shed a light on what I am missing in my code, that would be highly appreciated. Here is the camera class i use: public class Camera { private const float zoomUpperLimit = 1.5f; private const float zoomLowerLimit = 0.1f; private float _zoom; private Vector2 _pos; private int ViewportWidth, ViewportHeight; #region Properties public float Zoom { get { return _zoom; } set { _zoom = value; if (_zoom < zoomLowerLimit) _zoom = zoomLowerLimit; if (_zoom > zoomUpperLimit) _zoom = zoomUpperLimit; } } public Rectangle Viewport { get { int width = (int)((ViewportWidth / _zoom)); int height = (int)((ViewportHeight / _zoom)); return new Rectangle((int)(_pos.X - width / 2), (int)(_pos.Y - height / 2), width, height); } } public void Move(Vector2 amount) { _pos += amount; } public Vector2 Position { get { return _pos; } set { _pos = value; } } public Matrix View { get { return Matrix.CreateTranslation(new Vector3(-_pos.X, -_pos.Y, 0)) * Matrix.CreateScale(new Vector3(Zoom, Zoom, 1)) * Matrix.CreateTranslation(new Vector3(ViewportWidth * 0.5f, ViewportHeight * 0.5f, 0)); } } #endregion public Camera(Viewport viewport, float initialZoom) { _zoom = initialZoom; _pos = Vector2.Zero; ViewportWidth = viewport.Width; ViewportHeight = viewport.Height; } } And here is my Update and Draw-method: protected override void Update (GameTime gameTime) { float elapsed = (float)gameTime.ElapsedGameTime.TotalSeconds; TouchCollection touchCollection = TouchPanel.GetState (); foreach (TouchLocation tl in touchCollection) { if (tl.State == TouchLocationState.Pressed || tl.State == TouchLocationState.Moved) { //direction the tool shall move towards direction = touchCollection [0].Position - toolPos; if (direction != Vector2.Zero) { direction.Normalize (); } //change the direction the tool is moving and find the rotationangle the texture must rotate to point in given direction toolPos += (direction * speed * elapsed); RotationAngle = (float)Math.Atan2 (direction.Y, direction.X); } } if (direction != Vector2.Zero) { direction.Normalize (); } //move tool in given direction toolPos += (direction * speed * elapsed); //change cameracentre to the tools position Camera.Position = toolPos; base.Update (gameTime); } protected override void Draw (GameTime gameTime) { graphics.GraphicsDevice.Clear (Color.Blue); spriteBatch.Begin (SpriteSortMode.BackToFront, BlendState.AlphaBlend, null, null, null, null, Camera.View); spriteBatch.Draw (tool, new Vector2 (toolPos.X, toolPos.Y), null, Color.White, RotationAngle, originOfToolTexture, 1, SpriteEffects.None, 1); spriteBatch.End (); base.Draw (gameTime); }

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  • rotating spheres

    - by Dave
    I want to continuously rotate 2 spheres, however the rotation does not seem to work. Here is my code: float angle = 0.0f; void light(){ glEnable(GL_LIGHTING); glEnable(GL_LIGHT0); glEnable(GL_LIGHT1); // Create light components GLfloat positionlight1[] = { 9.0, 5.0, 1.0, 0.0 }; GLfloat positionlight2[] = {0.2,2.5,1.3,0.0}; GLfloat light_ambient1[] = { 0.0, 0.0, 1.0, 1.0}; GLfloat light_diffuse[] = { 1.0, 1.0, 1.0, 1.0 }; glLightfv(GL_LIGHT0, GL_AMBIENT, light_ambient1); glLightfv(GL_LIGHT1, GL_DIFFUSE, light_diffuse); glLightfv(GL_LIGHT0, GL_POSITION, positionlight1); glLightfv(GL_LIGHT1, GL_POSITION, positionlight2); } void changeSize(int w, int h) { if (h==0) // Prevent A Divide By Zero By { h=1; // Making Height Equal One } glMatrixMode(GL_PROJECTION); // Select The Projection Matrix glLoadIdentity(); // Reset The Projection Matrix glViewport(0,0,w,h);// Reset The Current Viewport // Calculate The Aspect Ratio Of The Window gluPerspective(45.0f,(GLfloat)w/(GLfloat)h,0.1f,100.0f); glMatrixMode(GL_MODELVIEW); // Select The Modelview Matrix // Reset The Modelview Matrix } void renderScene(void) { glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); glPushMatrix(); //set where to start the current object glTranslatef(0.0,1.2,-6); glRotatef(angle,0,1.2,-6); glutSolidSphere(1,50,50); glPopMatrix(); //end the current object transformations glPushMatrix(); //set where to start the current object glTranslatef(0.0,-2,-6); glRotatef(angle,0,-2,-6); glutSolidSphere(0.5,50,50); glPopMatrix(); //end the current object transformations angle=+0.1; glutSwapBuffers(); } int main(int argc, char **argv) { // init GLUT and create window glutInit(&argc, argv); glutInitDisplayMode(GLUT_DEPTH | GLUT_DOUBLE | GLUT_RGBA); glutInitWindowPosition(100,100); glutInitWindowSize(500,500); glutCreateWindow("Hello World"); // register callbacks light(); glutDisplayFunc(renderScene); glutReshapeFunc(changeSize); glutIdleFunc(renderScene); // enter GLUT event processing loop glutMainLoop(); return 1; } Graphicstest::Graphicstest(void) { } In the renderscene where i draw,translate and rotate my 2 spheres. It does not seem to rotate the spheres continuously. What am i doing wrong?

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  • Setting uniform value of a vertex shader for different sprites in a SpriteBatch

    - by midasmax
    I'm using libGDX and currently have a simple shader that does a passthrough, except for randomly shifting the vertex positions. This shift is a vec2 uniform that I set within my code's render() loop. It's declared in my vertex shader as uniform vec2 u_random. I have two different kind of Sprites -- let's called them SpriteA and SpriteB. Both are drawn within the same SpriteBatch's begin()/end() calls. Prior to drawing each sprite in my scene, I check the type of the sprite. If sprite instance of SpriteA: I set the uniform u_random value to Vector2.Zero, meaning that I don't want any vertex changes for it. If sprite instance of SpriteB, I set the uniform u_random to Vector2(MathUtils.random(), MathUtils.random(). The expected behavior was that all the SpriteA objects in my scene won't experience any jittering, while all SpriteB objects would be jittering about their positions. However, what I'm experiencing is that both SpriteA and SpriteB are jittering, leading me to believe that the u_random uniform is not actually being set per Sprite, and being applied to all sprites. What is the reason for this? And how can I fix this such that the vertex shader correctly accepts the uniform value set to affect each sprite individually? passthrough.vsh attribute vec4 a_color; attribute vec3 a_position; attribute vec2 a_texCoord0; uniform mat4 u_projTrans; uniform vec2 u_random; varying vec4 v_color; varying vec2 v_texCoord; void main() { v_color = a_color; v_texCoord = a_texCoord0; vec3 temp_position = vec3( a_position.x + u_random.x, a_position.y + u_random.y, a_position.z); gl_Position = u_projTrans * vec4(temp_position, 1.0); } Java Code this.batch.begin(); this.batch.setShader(shader); for (Sprite sprite : sprites) { Vector2 v = Vector2.Zero; if (sprite instanceof SpriteB) { v.x = MathUtils.random(-1, 1); v.y = MathUtils.random(-1, 1); } shader.setUniformf("u_random", v); sprite.draw(this.batch); } this.batch.end();

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  • How to avoid oscillation by async event based systems?

    - by inf3rno
    Imagine a system where there are data sources which need to be kept in sync. A simple example is model - view data binding by MVC. Now I intend to describe these kind of systems with data sources and hubs. Data sources are publishing and subscribing for events and hubs are relaying events to data sources. By handling an event a data source will change it state described in the event. By publishing an event the data source puts its current state to the event, so other data sources can use that information to change their state accordingly. The only problem with this system, that events can be reflected from the hub or from the other data sources, and that can put the system into an infinite oscillation (by async or infinite loop by sync). For example A -- data source B -- data source H -- hub A -> H -> A -- reflection from the hub A -> H -> B -> H -> A -- reflection from another data source By sync it is relatively easy to solve this issue. You can compare the current state with the event, and if they are equal, you don't change the state and raise the same event again. By async I could not find a solution yet. The state comparison does not work by async event handling because there is eventual consistency, and new events can be published in an inconsistent state causing the same oscillation. For example: A(*->x) -> H -> B(y->x) -- can go parallel with B(*->y) -> H -> A(x->y) -- so first A changes to x state while B changes to y state -- then B changes to x state while A changes to y state -- and so on for eternity... What do you think is there an algorithm to solve this problem? If there is a solution, is it possible to extend it to prevent oscillation caused by multiple hubs, multiple different events, etc... ? update: I don't think I can make this work without a lot of effort. I think this problem is just the same as we have by syncing multiple databases in a distributed system. So I think what I really need is constraints if I want to prevent this problem in an automatic way. What constraints do you suggest?

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