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• How to convert a 32bpp image to an indexed format?

  - by Ed Swangren

  So here are the details (I am using C# BTW): I receive a 32bpp image (JPEG compressed) from a server. At some point, I would like to use the Palette property of a bitmap to color over-saturated pixels (brightness 240) red. To do so, I need to get the image into an indexed format. I have tried converting the image to a GIF, but I get quality loss. I have tried creating a new bitmap in an index format by these methods: // causes a "Parameter not valid" error Bitmap indexed = new Bitmap(orig.Width, orig.Height, PixelFormat.Indexed) // no error, but the resulting image is black due to information loss I assume Bitmap indexed = new Bitmap(orig.Width, orig.Height, PixelFormat.Format8bppIndexed) I am at a loss now. The data in this image is changed constantly by the user, so I don't want to manually set pixels that have a brightness 240 if I can avoid it. If I can set the palette once when the image is created, my work is done. If I am going about this the wrong way to begin with please let me know. EDIT: Thanks guys, here is some more detail on what I am attempting to accomplish. We are scanning a tissue slide at high resolution (pathology application). I write the interface to the actual scanner. We use a line-scan camera. To test the line rate of the camera, the user scans a very small portion and looks at the image. The image is displayed next to a track bar. When the user moves the track bar (adjusting line rate), I change the overall intensity of the image in an attempt to model what it would look like at the new line rate. I do this using an ImageAttributes and ColorMatrix object currently. When the user adjusts the track bar, I adjust the matrix. This does not give me per pixel information, but the performance is very nice. I could use LockBits and some unsafe code here, but I would rather not rewrite it if possible. When the new image is created, I would like for all pixels with a brightness value of 240 to be colored red. I was thinking that defining a palette for the bitmap up front would be a clean way of doing this.

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• .NET: Avoidance of custom exceptions by utilising existing types, but which?

  - by Mr. Disappointment

  Consider the following code (ASP.NET/C#): private void Application_Start(object sender, EventArgs e) { if (!SetupHelper.SetUp()) { throw new ShitHitFanException(); } } I've never been too hesitant to simply roll my own exception type, basically because I have found (bad practice, or not) that mostly a reasonable descriptive type name gives us enough as developers to go by in order to know what happened and why something might have happened. Sometimes the existing .NET exception types even accommodate these needs - regardless of the message. In this particular scenario, for demonstration purposes only, the application should die a horrible, disgraceful death should SetUp not complete properly (as dictated by its return value), but I can't find an already existing exception type in .NET which would seem to suffice; though, I'm sure one will be there and I simply don't know about it. Brad Abrams posted this article that lists some of the available exception types. I say some because the article is from 2005, and, although I try to keep up to date, it's a more than plausible assumption that more have been added to future framework versions that I am still unaware of. Of course, Visual Studio gives you a nicely formatted, scrollable list of exceptions via Intellisense - but even on analysing those, I find none which would seem to suffice for this situation... ApplicationException: ...when a non-fatal application error occurs The name seems reasonable, but the error is very definitely fatal - the app is dead. ExecutionEngineException: ...when there is an internal error in the execution engine of the CLR Again, sounds reasonable, superficially; but this has a very definite purpose and to help me out here certainly isn't it. HttpApplicationException: ...when there is an error processing an HTTP request Well, we're running an ASP.NET application! But we're also just pulling at straws here. InvalidOperationException: ...when a call is invalid for the current state of an instance This isn't right but I'm adding it to the list of 'possible should you put a gun to my head, yes'. OperationCanceledException: ...upon cancellation of an operation the thread was executing Maybe I wouldn't feel so bad using this one, but I'd still be hijacking the damn thing with little right. You might even ask why on earth I would want to raise an exception here but the idea is to find out that if I were to do so then do you know of an appropriate exception for such a scenario? And basically, to what extent can we piggy-back on .NET while keeping in line with rationality?

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• Preserving Bitmap values when creating a new Bitmap from System.Drawing.Image

  - by Otaku

  I'm trying to create a resized image from a bitmap, set a new height/width and a new resolution and save it to PNG. I can do this either from directly A) Image.FromFile(filename) or B) New Bitmap(imageSource) to create the the A Bitmap to be passed to B. Both work okay schmokay, but A does not allow me to set a new width/height on creation (but it does allow me to preserve values with useIcm=True) and B does not allow me to preseve values. Okay, now on to some code and examples: Dim sourceBitmap As New Bitmap(imagePath & myImage1Name) <-not good at all (#1 overload). Doesn't preserve things like HorizontalResolution or PixelFormat on .Save Dim sourceBitmap2 As Bitmap = Image.FromFile(imagePath & myImage1Name, True) <-not good (#5 overload). it does preserve things like HorizontalResolution or PixelFormat on .Save, but it doesn't allow me to initialize image at a new size. Dim targetBitmap As New Bitmap(sourceBitmap2, newWidth, newHeight) <-not good. Even though sourceBitmap2 (see #2 above) was initialized with useIcm=True, it doesn't matter once I've passed it in as the source in targetBitmap. Basically, I'm looking for a way to contruct a New Bitmap with both something like useIcm=True and set the width/height at the same time (Width/Height are read-only properties once it's created). I've gone down the Graphics.DrawImage route as well and it's the same - Graphics.FromImage(sourceBitmap) does not preserve values. Why do I need these values to be preserved? Because I need to convert these pictures to PNG (for file size) with a new resolution and keep the same physical dimensions (w/h in inches) for printing. I know the new pixel width/height needed based on the resolution values I'll pass in with .SetResolution(xDpi,yDpi) to preserve physical dimensions, so that's not the problem. The issue is things like the PixelFormatSize need to remain unchanged (yes, I've tried EncoderParameters - they don't work. I can give you the gory details if you like, but suffice it to say for now, they just don't work). Whew, got that off my chest! Okay, anyone who really knows how all this works can help?

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

  - by Albz

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

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• How do I set libavcodec to use 4:2:2 chroma when encoding MPEG-2 4:2:2 profile?

  - by Mike Pollitt

  I have a project using libavcodec (ffmpeg). I'm using it to encode MPEG-2 video at 4:2:2 Profile, Main Level. I have the pixel format PIX_FMT_YUV422P selected in the AVCodecContext, however the video output I'm getting has all the colours wrong, and looks to me like the encoder is incorrectly reading the buffers as though it thinks it is 4:2:0 chroma rather than 4:2:2. Here's my codec setup: // // AVFormatContext* _avFormatContext previously defined as mpeg2video // // // Set up the video stream for output // AVVideoStream* _avVideoStream = av_new_stream(_avFormatContext, 0); if (!_avVideoStream) { err = ccErrWFFFmpegUnableToAllocateStream; goto bail; } _avCodecContext = _avVideoStream->codec; _avCodecContext->codec_id = CODEC_ID_MPEG2VIDEO; _avCodecContext->codec_type = CODEC_TYPE_VIDEO; // // Set up required parameters // _avCodecContext->rc_max_rate = _avCodecContext->rc_min_rate = _avCodecContext->bit_rate = src->_avCodecContext->bit_rate; _avCodecContext->flags = CODEC_FLAG_INTERLACED_DCT; _avCodecContext->flags2 = CODEC_FLAG2_INTRA_VLC | CODEC_FLAG2_NON_LINEAR_QUANT; _avCodecContext->qmin = 1; _avCodecContext->qmax = 1; _avCodecContext->rc_buffer_size = _avCodecContext->rc_initial_buffer_occupancy = 2000000; _avCodecContext->rc_buffer_aggressivity = 0.25; _avCodecContext->profile = 0; _avCodecContext->level = 5; _avCodecContext->width = f->GetWidth(); // f is a private Frame class with width, height properties etc. _avCodecContext->height = f->GetHeight(); _avCodecContext->time_base.den = 25; _avCodecContext->time_base.num = 1; _avCodecContext->gop_size = 12; _avCodecContext->max_b_frames = 2; _avCodecContext->pix_fmt = PIX_FMT_YUV422P; if (_avFormatContext->oformat->flags & AVFMT_GLOBALHEADER) { _avCodecContext->flags |= CODEC_FLAG_GLOBAL_HEADER; } if (av_set_parameters(_avFormatContext, NULL) < 0) { err = ccErrWFFFmpegUnableToSetParameters; goto bail; } // // Set up video codec for encoding // AVCodec* _avCodec = avcodec_find_encoder(_avCodecContext->codec_id); if (!_avCodec) { err = ccErrWFFFmpegUnableToFindCodecForOutput; goto bail; } if (avcodec_open(_avCodecContext, _avCodec) < 0) { err = ccErrWFFFmpegUnableToOpenCodecForOutput; goto bail; } A screengrab of the resulting video frame can be seen at http://ftp.limeboy.com/images/screen_grab.png (the input was standard colour bars). I've checked by outputting debug frames to TGA format at various points in the process, and I can confirm that it is all fine and dandy up until the point that libavcodec encodes the frame. Any assistance most appreciated! Cheers, Mike.

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• CSS RGBA border / background alpha double

  - by stockli

  I'm working on a website that has a lot of transparency involved, and I thought I would try to build it entirely in RGBA and then do fallbacks for IE. I need a "facebox" style border effect, where the outer border is rounded and is less opaque than the background of the box it surrounds. The last example from http://24ways.org/2009/working-with-rgba-colour seems to suggest that it's possible, but I can't seem to get it to work. When I try the following: <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en"> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8"/> <title>RGBA Test</title> <style type='text/css'> body { background: #000; color: #fff; } #container { width: 700px; margin: 0 auto; background: rgba(255, 255, 255, 0.2); border: 10px solid rgba(255, 255, 255, 0.1); padding: 20px; } </style> </head> <body> <div id='container'> This should look like a facebox. </div> </body></html> It seems like the background "extends" underneath the border of the element, which causes the pixel values to get added together. Thus, when both the background and the border are semi-transparent, the border will ALWAYS be more opaque than the background of the element. This is exactly the opposite of what I am trying to achieve, but it seems like it should be possible based on the examples I've seen. I should also add that I can't use another element inside the container, because I'm also going to use a border-radius on the container to get rounded corners, and webkit squares the corners of the child elements if they have a background assigned, which would essentially mean a rounded outer border with square contents. Sorry I can't post an image of this... Apparently I don't have enough rep to post an image.

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• 3 embedded UIScrollView problem

  - by Infinity

  Hello guys! I have 3 UIScrollView. Here is a sample code, about how they are added in eachother: UIScrollView main; UIScrollView page1; UIScrollView page2; UIScrollView doublePage; UIView pageContent1; UIView pageContent2; UIView doublePageContent; int nrPages = 1; sw2 = 0; main = [[UIScrollView alloc] initWithFrame:CGRectMake(0.0, 0.0, 768, 980)]; main.contentSize = CGSizeMake(768 * (nrPages - 1 + sw2), 980); page1.frame = CGRectMake(0, 0, 768, 980); page2.frame = CGRectMake(768, 0, 768, 980); pageNumber = i - 1 + sw2; (i is a variable in a for loop) doublePage.frame = CGRectMake(768 * (pageNumber - 1), 0, 768 * 2, 980); CGFloat contentWidth = [page1 bounds].size.width + [page2 bounds].size.width; CGFloat contentHeight = page1 ? self.page1.bounds.size.height : self.page2.bounds.size.height; doublePageContent = [[UIView alloc] initWithFrame:CGRectMake(0, 0, contentWidth, contentHeight)]; [page1 addSubview:pageContent1]; [page2 addSubview:pageContent2]; [doublePageContent addSubview:page1]; [doublePageContent addSubview:page2]; [doublePage addSubview:doublePageContent]; [main addSubview:doublepage]; And with this structure the main scrollview don't want to scroll. Without the doublepage scrollview it is working good. What do you think? What's the problem? I know this structure is a little weird, but I need this structure because other parts of the code. Edited, added the information about the sizes. If you need something more please tell me. And one more thing.. If I add 1 pixel to the width of the doublePage contentSize.width it scrolls, but a bit hard, so it scrolls first in the doublePage and then in the main.

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• If statement within If statement's else

  - by maebe

  Still new to Java/android so trying to figure out the best way to code a multilevel if statement. What I'm trying to do is for a combat system that needs to check if player/npc is alive. If they are alive it then will check to see if they scored a critical hit. If they didn't critical hit then will see if they hit or missed. combat = mydbhelper.getCombat(); startManagingCursor(combat); if(playerCurHp == 0){ combat.moveToPosition(11); npcCombatStory = combat.getString(combat.getColumnIndex(dbhelper.KEY_COMBATDESC));} else{ if(playerCritFlag.equals("Critical")){ combat.moveToPosition(2); playerCombatStory = combat.getString(combat.getColumnIndex(dbhelper.KEY_COMBATDESC));} else{ if(playerHitFlag.equals("Hit")){ combat.moveToPosition(1); playerCombatStory = combat.getString(combat.getColumnIndex(dbhelper.KEY_COMBATDESC));} if(playerHitFlag.equals("Miss")){ combat.moveToPosition(3); playerCombatStory = combat.getString(combat.getColumnIndex(dbhelper.KEY_COMBATDESC));} }} if (npcCurHp == 0){ combat.moveToPosition(10); npcCombatStory = combat.getString(combat.getColumnIndex(dbhelper.KEY_COMBATDESC));} else{ if(npcCritFlag.equals("Critical")){ combat.moveToPosition(5); npcCombatStory = combat.getString(combat.getColumnIndex(dbhelper.KEY_COMBATDESC));} else{ if(npcHitFlag.equals("Hit")){ combat.moveToPosition(4); npcCombatStory = combat.getString(combat.getColumnIndex(dbhelper.KEY_COMBATDESC));} if(npcHitFlag.equals("Miss")){ combat.moveToPosition(6); npcCombatStory = combat.getString(combat.getColumnIndex(dbhelper.KEY_COMBATDESC));} }} } Is what I'm using. Was working when I had the if statements all separate. But it would check each one and do actions I don't need (If they hit, pull String, if crit pull another, then if dead pull again). Trying to make it stop when it finds the "Flag" that matches. When doing my rolls if the player hits it sets the flag to "Hit" like below code. Random attackRandom = new Random(); int attackRoll = attackRandom.nextInt(100); totalAtt = attackRoll + bonusAttack + weaponAtt + stanceAtt; Random defensiveRandom = new Random(); int defenseRoll = defensiveRandom.nextInt(100); npcDef = defenseRoll + npcDodge + npcBonusDodge; if (totalAtt > npcDef){ playerHitFlag = "Hit"; playerDamage();} else{playerHitFlag = "Miss"; npcAttack();} At the end it takes these playerCombatStory and npcCombatStory strings and uses them to setText to show the player what happened on that turn of combat.

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• Best method for converting several sets of numbers with several different ratios

  - by C Patton

  I'm working on an open-source harm reduction application for opioid addicts. One of the features in this application is the conversion (in mg/mcg) between common opioids, so people don't overdose by accident. If you're morally against opioid addiction and wouldn't respond because of your morals, please consider that this application is for HARM REDUCTION.. So people don't end up dead. I have this data.. 3mg morphine IV = 10mcg fentanyl IV 2mg morphine oral = 1mg oxycodone oral 3mg oral morphine = 1mg oxymorphone oral 7.0mg morphine oral = 1mg hydromorphone oral 1mg morphine iv = .10mg oxymorphone iv 1mg morphine oral = 1mg hydrocodone oral 1mg morphine oral = 6.67mg codeine oral 1mg morphine oral = .10mg methadone oral And I have a textbox that is the source dosage in mg (a double) that the user can enter in. Underneath this, I have radio boxes for the source substance (ie: morphine) and the destination substance (ie oxycodone) for conversion.. I've been trying to think of the most efficient way to do this, but nearly every seems sloppy. If I were to do something like public static double MorphinetoOxycodone(string morphineValue) { double morphine = Double.Parse(morphineValue); return (morphine / 2 ); } I would also have to make a function for OxycodonetoMorphine, OxycodonetoCodeine, etc.. and then would end up with dozens functions.. There must be an easier way than this that I'm missing. If you'll notice, all of my conversions use morphine as the base value.. what might be the easiest way to use the morphine value to convert one opioid to another? For example, if 1mg morphine oral is equal to 1mg hydrocodone and 1mg morphine oral is equal to .10mg methadone, wouldn't I just multiply 1*.10 to get the hydrocodone-methadone value? Implementing this idea is what I'm having the most trouble with. Any help would be GREATLY appreciated.. and if you'd like, I would add your name/nickname to the credits in this program. It's possible that many, many people around the world will use this (I'm translating it into several languages as well) and to know that your work could've helped an addict from dying.. I think that's a great thing :) -cory

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• problem in adding image to JFrame

  - by firestruq

  Hi, I'm having problems in adding a picture into JFrame, something is missing probebly or written wrong. here are the classes: main class: public class Tester { public static void main(String args[]) { BorderLayoutFrame borderLayoutFrame = new BorderLayoutFrame(); borderLayoutFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); borderLayoutFrame.setSize(600,600); borderLayoutFrame.setVisible(true); } } public class BorderLayoutFrame extends JFrame implements ActionListener { private JButton buttons[]; // array of buttons to hide portions private final String names[] = { "North", "South", "East", "West", "Center" }; private BorderLayout layout; // borderlayout object private PicPanel picture = new PicPanel(); // set up GUI and event handling public BorderLayoutFrame() { super( "Philosofic Problem" ); layout = new BorderLayout( 5, 5 ); // 5 pixel gaps setLayout( layout ); // set frame layout buttons = new JButton[ names.length ]; // set size of array // create JButtons and register listeners for them for ( int count = 0; count < names.length; count++ ) { buttons[ count ] = new JButton( names[ count ] ); buttons[ count ].addActionListener( this ); } add( buttons[ 0 ], BorderLayout.NORTH ); // add button to north add( buttons[ 1 ], BorderLayout.SOUTH ); // add button to south add( buttons[ 2 ], BorderLayout.EAST ); // add button to east add( buttons[ 3 ], BorderLayout.WEST ); // add button to west add( picture, BorderLayout.CENTER ); // add button to center } // handle button events public void actionPerformed( ActionEvent event ) { } } I'v tried to add the image into the center of layout. here is the image class: public class PicPanel extends JPanel { Image img; private int width = 0; private int height = 0; public PicPanel() { super(); img = Toolkit.getDefaultToolkit().getImage("table.jpg"); } public void paintComponent(Graphics g) { super.paintComponents(g); if ((width <= 0) || (height <= 0)) { width = img.getWidth(this); height = img.getHeight(this); } g.drawImage(img,0,0,width,height,this); } } Please your help, what is the problem? thanks BTW: i'm using eclipse, which directory the image suppose to be in?

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• Why SQL2008 debugger would NOT step into a certain child stored procedure

  - by John Galt

  I'm encountering differences in T-SQL with SQL2008 (vs. SQL2000) that are leading me to dead-ends. I've verified that the technique of sharing #TEMP tables between a caller which CREATES the #TEMP and the child sProc which references it remain valid in SQL2008 See recent SO question. My core problem remains a critical "child" stored procedure that works fine in SQL2000 but fails in SQL2008 (i.e. a FROM clause in the child sProc is coded as: SELECT * FROM #AREAS A) despite #AREAS being created by the calling parent. Rather than post snippets of the code now, here is another symptom that may help you suggest something. I fired up the new debugger in SQL Mgmt Studio: EXEC dbo.AMS1 @S1='06',@C1='037',@StartDate='01/01/2008',@EndDate='07/31/2008',@Type=1,@ACReq = 1,@Output = 0,@NumofLines = 30,@SourceTable = 'P',@LoanPurposeCatg='P' This is a very large sProc and the key snippet that is weird is the following: **create table #Areas ( State char(2) , County char(3) , ZipCode char(5) NULL , CityName varchar(28) NULL , PData varchar(3) NULL , RData varchar(3) NULL , SMSA_CD varchar(10) NULL , TypeCounty varchar(50) , StateAbbr char(2) ) EXECUTE dbo.AMS_I_GetAreasV5 -- this child populates #Areas @SMSA = @SMSA , @S1 = @S1 , @C1 = @C1 , @Z1 = @Z1 , @SourceTable = @SourceTable , @CustomID = @CustomID , @UserName = @UserName , @CityName = @CityName , @Debug=0 EXECUTE dbo.AMS_I_GetAreas_FixAC -- this child cannot reference #Areas @StartDate = @StartDate , @EndDate = @EndDate , @SMSA_CD = @SMSA_CD , @S1 = @S1 , @C1 = @C1 , @Z1 = @Z1 , @CityName = @CityName , @CustomID = @CustomID , @Debug=0 -- continuation of the parent sProc** I can step through the execution of the parent stored procedure. When I get to the first child sproc above, I can either STEP INTO dbo.AMS_I_GetAreasV5 or STEP OVER its execution. When I arrive at the invocation of the 2nd child sProc - dbo.AMS_I_GetAreas_FixAC - I try to STEP INTO it (because that is where the problem statement is) and STEP INTO is ignored (i.e. treated like STEP OVER instead; yet I KNOW I pressed F11 not F10). It WAS executed however, because when control is returned to the statement after the EXECUTE, I click Continue to finish execution and the results windows shows the errors in the dbo.AMS_I_GetAreas_FixAC (i.e. the 2nd child) stored procedure. Is there a way to "pre-load" an sProc with the goal of setting a breakpoint on its entry so that I can pursue execution inside it? In summary, I wonder if the inability to step into a given child sproc might be related to the same inability of this particular child to reference a #temp created by its parent (caller).

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• How to manage multiple versions of the same record

  - by Darvis Lombardo

  I am doing short-term contract work for a company that is trying to implement a check-in/check-out type of workflow for their database records. Here's how it should work... 1) A user creates a new entity within the application. There are about 20 related tables that will be populated in addition to the main entity table. 2) Once the entity is created the user will mark it as the master. 3) Another user can make changes to the master only by "checking out" the entity. Multiple users can checkout the entity at the same time. 4) Once the user has made all the necessary changes to the entity, they put it in a "needs approval" status. 5) After an authorized user reviews the entity, they can promote it to master which will put the original record in a tombstoned status. The way they are currently accomplishing the "check out" is by duplicating the entity records in all the tables. The primary keys include EntityID + EntityDate, so they duplicate the entity records in all related tables with the same EntityID and an updated EntityDate and give it a status of "checked out". When the record is put into the next state (needs approval), the duplication occurs again. Eventually it will be promoted to master at which time the final record is marked as master and the original master is marked as dead. This design seems hideous to me, but I understand why they've done it. When someone looks up an entity from within the application, they need to see all current versions of that entity. This was a very straightforward way for making that happen. But the fact that they are representing the same entity multiple times within the same table(s) doesn't sit well with me, nor does the fact that they are duplicating EVERY piece of data rather than only storing deltas. I would be interested in hearing your reaction to the design, whether positive or negative. I would also be grateful for any resoures you can point me to that might be useful for seeing how someone else has implemented such a mechanism. Thanks! Darvis

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• How do I do high quality scaling of a image?

  - by pbhogan

  I'm writing some code to scale a 32 bit RGBA image in C/C++. I have written a few attempts that have been somewhat successful, but they're slow and most importantly the quality of the sized image is not acceptable. I compared the same image scaled by OpenGL (i.e. my video card) and my routine and it's miles apart in quality. I've Google Code Searched, scoured source trees of anything I thought would shed some light (SDL, Allegro, wxWidgets, CxImage, GD, ImageMagick, etc.) but usually their code is either convoluted and scattered all over the place or riddled with assembler and little or no comments. I've also read multiple articles on Wikipedia and elsewhere, and I'm just not finding a clear explanation of what I need. I understand the basic concepts of interpolation and sampling, but I'm struggling to get the algorithm right. I do NOT want to rely on an external library for one routine and have to convert to their image format and back. Besides, I'd like to know how to do it myself anyway. :) I have seen a similar question asked on stack overflow before, but it wasn't really answered in this way, but I'm hoping there's someone out there who can help nudge me in the right direction. Maybe point me to some articles or pseudo code... anything to help me learn and do. Here's what I'm looking for: 1. No assembler (I'm writing very portable code for multiple processor types). 2. No dependencies on external libraries. 3. I am primarily concerned with scaling DOWN, but will also need to write a scale up routine later. 4. Quality of the result and clarity of the algorithm is most important (I can optimize it later). My routine essentially takes the following form: DrawScaled( uint32 *src, uint32 *dst, src_x, src_y, src_w, src_h, dst_x, dst_y, dst_w, dst_h ); Thanks! UPDATE: To clarify, I need something more advanced than a box resample for downscaling which blurs the image too much. I suspect what I want is some kind of bicubic (or other) filter that is somewhat the reverse to a bicubic upscaling algorithm (i.e. each destination pixel is computed from all contributing source pixels combined with a weighting algorithm that keeps things sharp. EXAMPLE: Here's an example of what I'm getting from the wxWidgets BoxResample algorithm vs. what I want on a 256x256 bitmap scaled to 55x55. And finally: the original 256x256 image

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• Need a fast programming language that can drive two printers

  - by Pete

  I have a rather unusual application that isn't working the way I need, and I hope someone here will have some suggestions or at least a direction to investigate. We have a museum exhibit that has a computer at the entrance driving two small receipt printers. There are two buttons on a console, wired to the left and right buttons of a disemboweled mouse. The two printers and associated buttons are for girls and boys, each button does a random selection from a database of names and prints a small ticket on the appropriate printer with a graphic image, a few words about the exhibit and the randomly chosen name. Conceptually all is well, but it hangs quite often. I got the project at the last minute, because the original designer got bogged down and couldn't deliver, so the exhibit's author asked me the day before opening, whether I could write something that would work. I did it in Word, since I am an experienced VBA programmer. Several other avenues I attempted first all lead to dead ends - one couldn't do graphics, another couldn't handle two printers, yet another couldn't change fonts and so on. The problem is that it simply isn't fast enough - Word can only drive one printer at a time and changing the active printer takes a long time. Not by office standards, where a second or two of delay before a printer starts working on your document is not an issue, but here I need more or less instant response. If kids press a button and nothing happens, they press it over and over until something does happen, resulting in maybe half a dozen commands being sent before the printer starts reacting. Sometimes it jams the program completely, since boys and girls will be pressing the two buttons simultaneously and Word locks up, and even when it doesn't jam, the printers then spit out a stream of tickets, making a mess. The kids start squabbling over which ticket is whose, pulling them out of the printers, snarling the paper tape, jamming the printer and generally making a mess of the whole affair, often necessitating the exhibit caretakers having to restart the computer and clear torn bits of paper out the printers. What I need is some sort of fast programming language that can drive two printers *-simultaneously-*, not the MSOffice claptrap of having to switch the active printer, that can react to both left and right mouse button click events, can print a small graphic image and can print in different font sizes and styles and. I don't need many, but it's not all in one typeface. Can anyone suggest what I might use for this? I don't even know if it's possible at all under Windows, whether the "single active printer" garbage is an Office artifact, or a Windows restriction. My little Commodore-64 twenty-five years ago had two printers attached to it and drove both simultaneously with no difficulties - it doesn't seem to me it should be such an impossible requirement today.

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• Opinions on collision detection objects with a moving scene

  - by Evan Teran

  So my question is simple, and I guess it boils down to how anal you want to be about collision detection. To keep things simple, lets assume we're talking about 2D sprites defined by a bounding box. In addition, let's assume that my sprite object has a function to detect collisions like this: S.collidesWith(other); Finally the scene is moving and "walls" in the scene can move, an object may not touch a wall. So a simple implementation might look like this (psuedo code): moveWalls(); moveSprite(); foreach(wall as w) { if(s.collidesWith(w)) { gameover(); } } The problem with this is that if the sprite and wall move towards each other, depending on the circumstances (such as diagonal moment). They may pass though each other (unlikely but could happen). So I may do this instead. moveWalls(); foreach(wall as w) { if(s.collidesWith(w)) { gameover(); } } moveSprite(); foreach(wall as w) { if(s.collidesWith(w)) { gameover(); } } This takes care of the passing through each other issue, but another rare issue comes up. If they are adjacent to each other (literally the next pixel) and both the wall and the sprite are moving left, then I will get an invalid collision since the wall moves, checks for collision (hit) then the sprite is moved. Which seems unfair. In addition, to that, the redundant collision detection feels very inefficient. I could give the player movement priority alleviating the first issue but it is still checking twice. moveSprite(); foreach(wall as w) { if(s.collidesWith(w)) { gameover(); } } moveWalls(); foreach(wall as w) { if(s.collidesWith(w)) { gameover(); } } Am I simply over thinking this issue, should this just be chalked up to "it'll happen rare enough that no one will care"? Certainly looking at old sprite based games, I often find situations where the collision detection has subtle flaws, but I figure by now we can do better :-P. What are people's thoughts?

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• When to call glEnable(GL_FRAMEBUFFER_SRGB)?

  - by Steven Lu

  I have a rendering system where I draw to an FBO with a multisampled renderbuffer, then blit it to another FBO with a texture in order to resolve the samples in order to read off the texture to perform post-processing shading while drawing to the backbuffer (FBO index 0). Now I'd like to get some correct sRGB output... The problem is the behavior of the program is rather inconsistent between when I run it on OS X and Windows and this also changes depending on the machine: On Windows with the Intel HD 3000 it will not apply the sRGB nonlinearity but on my other machine with a Nvidia GTX 670 it does. On the Intel HD 3000 in OS X it will also apply it. So this probably means that I'm not setting my GL_FRAMEBUFFER_SRGB enable state at the right points in the program. However I can't seem to find any tutorials that actually tell me when I ought to enable it, they only ever mention that it's dead easy and comes at no performance cost. I am currently not loading in any textures so I haven't had a need to deal with linearizing their colors yet. To force the program to not simply spit back out the linear color values, what I have tried is simply comment out my glDisable(GL_FRAMEBUFFER_SRGB) line, which effectively means this setting is enabled for the entire pipeline, and I actually redundantly force it back on every frame. I don't know if this is correct or not. It certainly does apply a nonlinearization to the colors but I can't tell if this is getting applied twice (which would be bad). It could apply the gamma as I render to my first FBO. It could do it when I blit the first FBO to the second FBO. Why not? I've gone so far as to take screen shots of my final frame and compare raw pixel color values to the colors I set them to in the program: I set the input color to RGB(1,2,3) and the output is RGB(13,22,28). That seems like quite a lot of color compression at the low end and leads me to question if the gamma is getting applied multiple times. I have just now gone through the sRGB equation and I can verify that the conversion seems to be only applied once as linear 1/255, 2/255, and 3/255 do indeed map to sRGB 13/255, 22/255, and 28/255 using the equation 1.055*C^(1/2.4)+0.055. Given that the expansion is so large for these low color values it really should be obvious if the sRGB color transform is getting applied more than once. So, I still haven't determined what the right thing to do is. does glEnable(GL_FRAMEBUFFER_SRGB) only apply to the final framebuffer values, in which case I can just set this during my GL init routine and forget about it hereafter?

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• How do I stack images to simulate depth using Core Animation?

  - by Jeffrey Berthiaume

  I have a series of UIImages with which I need to simulate depth. I can't use scaling because I need to be able to rotate the parent view, and the images should look like they're stacked visibly in front of each other, not on the same plane. I made a new ViewController-based project and put this in the viewDidLoad (as well as attached three 120x120 pixel images named 1.png, 2.png, and 3.png): - (void)viewDidLoad { // display image 3 UIImageView *three = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"3.png"]]; three.center = CGPointMake(160 + 60, 240 - 60); [self.view addSubview:three]; // rotate image 3 around the z axis // THIS IS INCORRECT CATransform3D theTransform = three.layer.transform; theTransform.m34 = 1.0 / -1000; three.layer.transform = theTransform; // display image 2 UIImageView *two = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"2.png"]]; two.center = CGPointMake(160, 240); [self.view addSubview:two]; // display image 1 UIImageView *one = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"1.png"]]; one.center = CGPointMake(160 - 60, 240 + 60); [self.view addSubview:one]; // rotate image 3 around the z axis // THIS IS INCORRECT theTransform = one.layer.transform; theTransform.m34 = 1.0 / 1000; one.layer.transform = theTransform; // release the images [one release]; [two release]; [three release]; // rotate the parent view around the y axis theTransform = self.view.layer.transform; theTransform.m14 = 1.0 / -500; self.view.layer.transform = theTransform; [super viewDidLoad]; } I have very specific reasons why I'm not using an EAGLView and why I'm not loading the images as CALayers (i.e. why I'm using UIImageViews for each one). This is just a quick demo that I can use to work out exactly what I need in my parent application. Is there some matrix way to translate these 2d images along the z-axis so they will look like what I'm trying to represent? I've gone through the other StackOverflow articles as well as the Wikipedia references, and have not found what I'm looking for -- although I might not necessarily be using the right terms for what I'm trying to do.

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• How to resize an openGL window created with wglCreateContext?

  - by Nick

  Is it possible to resize an openGL window (or device context) created with wglCreateContext without disabling it? If so how? Right now I have a function which resizes the DC but the only way I could get it to work was to call DisableOpenGL and then re-enable. This causes any textures and other state changes to be lost. I would like to do this without the disable so that I do not have to go through the tedious task of recreating the openGL DC state. HWND hWnd; HDC hDC; void View_setSizeWin32(int width, int height) { // resize the window LPRECT rec = malloc(sizeof(RECT)); GetWindowRect(hWnd, rec); SetWindowPos( hWnd, HWND_TOP, rec->left, rec->top, rec->left+width, rec->left+height, SWP_NOMOVE ); free(rec); // sad panda DisableOpenGL( hWnd, hDC, hRC ); EnableOpenGL( hWnd, &hDC, &hRC ); glMatrixMode(GL_PROJECTION); glLoadIdentity(); glOrtho(-(width/2), width/2, -(height/2), height/2, -1.0, 1.0); // have fun recreating the openGL state.... } void EnableOpenGL(HWND hWnd, HDC * hDC, HGLRC * hRC) { PIXELFORMATDESCRIPTOR pfd; int format; // get the device context (DC) *hDC = GetDC( hWnd ); // set the pixel format for the DC ZeroMemory( &pfd, sizeof( pfd ) ); pfd.nSize = sizeof( pfd ); pfd.nVersion = 1; pfd.dwFlags = PFD_DRAW_TO_WINDOW | PFD_SUPPORT_OPENGL | PFD_DOUBLEBUFFER; pfd.iPixelType = PFD_TYPE_RGBA; pfd.cColorBits = 24; pfd.cDepthBits = 16; pfd.iLayerType = PFD_MAIN_PLANE; format = ChoosePixelFormat( *hDC, &pfd ); SetPixelFormat( *hDC, format, &pfd ); // create and enable the render context (RC) *hRC = wglCreateContext( *hDC ); wglMakeCurrent( *hDC, *hRC ); } void DisableOpenGL(HWND hWnd, HDC hDC, HGLRC hRC) { wglMakeCurrent( NULL, NULL ); wglDeleteContext( hRC ); ReleaseDC( hWnd, hDC ); }

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• OpenGL, how to set a monochrome texture to a colored shape?

  - by Santiago

  I'm developing on Android with OpenGL ES, I draw some cubes and I change its colors with glColor4f. Now, what I want is to give a more realistic effect on the cubes, so I create a monochromatic 8bit depth, 64x64 pixel size PNG file. I loaded on a texture, and here is my problem, witch is the way to combine the color and the texture to get a colorized and textured cubes onto the screen? I'm not an expert on OpenGL, I tried this: On create: public void asignBitmap(GL10 gl, Bitmap bitmap) { int[] textures = new int[1]; gl.glGenTextures(1, textures, 0); mTexture = textures[0]; gl.glBindTexture(GL10.GL_TEXTURE_2D, mTexture); gl.glTexParameterf(GL10.GL_TEXTURE_2D, GL10.GL_TEXTURE_MIN_FILTER, GL10.GL_NEAREST); gl.glTexParameterf(GL10.GL_TEXTURE_2D, GL10.GL_TEXTURE_MAG_FILTER, GL10.GL_LINEAR); gl.glTexParameterf(GL10.GL_TEXTURE_2D, GL10.GL_TEXTURE_WRAP_S, GL10.GL_CLAMP_TO_EDGE); gl.glTexParameterf(GL10.GL_TEXTURE_2D, GL10.GL_TEXTURE_WRAP_T, GL10.GL_CLAMP_TO_EDGE); gl.glTexEnvf(GL10.GL_TEXTURE_ENV, GL10.GL_TEXTURE_ENV_MODE, GL10.GL_REPLACE); GLUtils.texImage2D(GL10.GL_TEXTURE_2D, 0, GL10.GL_ALPHA, bitmap, 0); ByteBuffer tbb = ByteBuffer.allocateDirect(texCoords.length * 4); tbb.order(ByteOrder.nativeOrder()); mTexBuffer = tbb.asFloatBuffer(); for (int i = 0; i < 48; i++) mTexBuffer.put(texCoords[i]); mTexBuffer.position(0); } And OnDraw: public void draw(GL10 gl, int alphawires) { gl.glColor4f(1.0f, 0.0f, 0.0f, 0.5f); //RED gl.glBindTexture(GL10.GL_TEXTURE_2D, mTexture); gl.glBlendFunc(GL10.GL_SRC_ALPHA, GL10.GL_ONE_MINUS_SRC_ALPHA); gl.glEnable(GL10.GL_TEXTURE_2D); gl.glEnable(GL10.GL_BLEND); gl.glEnableClientState(GL10.GL_TEXTURE_COORD_ARRAY); gl.glTexCoordPointer(2, GL10.GL_FLOAT, 0, mTexBuffer); //Set the face rotation gl.glFrontFace(GL10.GL_CW); //Point to our buffers gl.glVertexPointer(3, GL10.GL_FLOAT, 0, vertexBuffer); //Enable the vertex and color state gl.glEnableClientState(GL10.GL_VERTEX_ARRAY); //Draw the vertices as triangles, based on the Index Buffer information gl.glDrawElements(GL10.GL_TRIANGLES, 36, GL10.GL_UNSIGNED_BYTE, indexBuffer); //Disable the client state before leaving gl.glDisableClientState(GL10.GL_VERTEX_ARRAY); gl.glDisableClientState(GL10.GL_TEXTURE_COORD_ARRAY); gl.glDisable(GL10.GL_BLEND); gl.glDisable(GL10.GL_TEXTURE_2D); } I'm even not sure if I have to use a blend option, because I don't need transparency, but is a plus :)

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• All possible combinations of length 8 in a 2d array

  - by CodeJunki

  Hi, I've been trying to solve a problem in combinations. I have a matrix 6X6 i'm trying to find all combinations of length 8 in the matrix. I have to move from neighbor to neighbor form each row,column position and i wrote a recursive program which generates the combination but the problem is it generates a lot of duplicates as well and hence is inefficient. I would like to know how could i eliminate calculating duplicates and save time. int a={{1,2,3,4,5,6}, {8,9,1,2,3,4}, {5,6,7,8,9,1}, {2,3,4,5,6,7}, {8,9,1,2,3,4}, {5,6,7,8,9,1}, } void genSeq(int row,int col,int length,int combi) { if(length==8) { printf("%d\n",combi); return; } combi = (combi * 10) + a[row][col]; if((row-1)>=0) genSeq(row-1,col,length+1,combi); if((col-1)>=0) genSeq(row,col-1,length+1,combi); if((row+1)<6) genSeq(row+1,col,length+1,combi); if((col+1)<6) genSeq(row,col+1,length+1,combi); if((row+1)<6&&(col+1)<6) genSeq(row+1,col+1,length+1,combi); if((row-1)>=0&&(col+1)<6) genSeq(row-1,col+1,length+1,combi); if((row+1)<6&&(row-1)>=0) genSeq(row+1,col-1,length+1,combi); if((row-1)>=0&&(col-1)>=0) genSeq(row-1,col-1,length+1,combi); } I was also thinking of writing a dynamic program basically recursion with memorization. Is it a better choice?? if yes than I'm not clear how to implement it in recursion. Have i really hit a dead end with approach??? Thankyou Edit Eg result 12121212,12121218,12121219,12121211,12121213. the restrictions are that you have to move to your neighbor from any point, you have to start for each position in the matrix i.e each row,col. you can move one step at a time, i.e right, left, up, down and the both diagonal positions. Check the if conditions. i.e if your in (0,0) you can move to either (1,0) or (1,1) or (0,1) i.e three neighbors. if your in (2,2) you can move to eight neighbors. so on...

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• OpenGL, how to set a monocrome texture to a colored shape?

  - by Santiago

  I'm developing on Android with OpenGL ES, I draw some cubes and I change its colors with glColor4f. Now, what I want is to give a more realistic effect on the cubes, so I create a monochromatic 8bit depth, 64x64 pixel size PNG file. I loaded on a texture, and here is my problem, witch is the way to combine the color and the texture to get a colorized and textured cubes onto the screen? I'm not an expert on OpenGL, I tried this: On create: public void asignBitmap(GL10 gl, Bitmap bitmap) { int[] textures = new int[1]; gl.glGenTextures(1, textures, 0); mTexture = textures[0]; gl.glBindTexture(GL10.GL_TEXTURE_2D, mTexture); gl.glTexParameterf(GL10.GL_TEXTURE_2D, GL10.GL_TEXTURE_MIN_FILTER, GL10.GL_NEAREST); gl.glTexParameterf(GL10.GL_TEXTURE_2D, GL10.GL_TEXTURE_MAG_FILTER, GL10.GL_LINEAR); gl.glTexParameterf(GL10.GL_TEXTURE_2D, GL10.GL_TEXTURE_WRAP_S, GL10.GL_CLAMP_TO_EDGE); gl.glTexParameterf(GL10.GL_TEXTURE_2D, GL10.GL_TEXTURE_WRAP_T, GL10.GL_CLAMP_TO_EDGE); gl.glTexEnvf(GL10.GL_TEXTURE_ENV, GL10.GL_TEXTURE_ENV_MODE, GL10.GL_REPLACE); GLUtils.texImage2D(GL10.GL_TEXTURE_2D, 0, GL10.GL_ALPHA, bitmap, 0); ByteBuffer tbb = ByteBuffer.allocateDirect(texCoords.length * 4); tbb.order(ByteOrder.nativeOrder()); mTexBuffer = tbb.asFloatBuffer(); for (int i = 0; i < 48; i++) mTexBuffer.put(texCoords[i]); mTexBuffer.position(0); } And OnDraw: public void draw(GL10 gl, int alphawires) { gl.glColor4f(1.0f, 0.0f, 0.0f, 0.5f); //RED gl.glBindTexture(GL10.GL_TEXTURE_2D, mTexture); gl.glBlendFunc(GL10.GL_SRC_ALPHA, GL10.GL_ONE_MINUS_SRC_ALPHA); gl.glEnable(GL10.GL_TEXTURE_2D); gl.glEnable(GL10.GL_BLEND); gl.glEnableClientState(GL10.GL_TEXTURE_COORD_ARRAY); gl.glTexCoordPointer(2, GL10.GL_FLOAT, 0, mTexBuffer); //Set the face rotation gl.glFrontFace(GL10.GL_CW); //Point to our buffers gl.glVertexPointer(3, GL10.GL_FLOAT, 0, vertexBuffer); //Enable the vertex and color state gl.glEnableClientState(GL10.GL_VERTEX_ARRAY); //Draw the vertices as triangles, based on the Index Buffer information gl.glDrawElements(GL10.GL_TRIANGLES, 36, GL10.GL_UNSIGNED_BYTE, indexBuffer); //Disable the client state before leaving gl.glDisableClientState(GL10.GL_VERTEX_ARRAY); gl.glDisableClientState(GL10.GL_TEXTURE_COORD_ARRAY); gl.glDisable(GL10.GL_BLEND); gl.glDisable(GL10.GL_TEXTURE_2D); } I'm even not sure if I have to use a blend option, because I don't need transparency, but is a plus :) Thank's

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• OpenGL Coordinate system confusion

  - by user146780

  Maybe I set up GLUT wrong. Basically I want verticies to be reletive to their size in pixels. Ex:right now if I create a hexagon, it hakes up the whole screen even though the units are 6. #include <iostream> #include <stdlib.h> //Needed for "exit" function #include <cmath> //Include OpenGL header files, so that we can use OpenGL #ifdef __APPLE__ #include <OpenGL/OpenGL.h> #include <GLUT/glut.h> #else #include <GL/glut.h> #endif using namespace std; //Called when a key is pressed void handleKeypress(unsigned char key, //The key that was pressed int x, int y) { //The current mouse coordinates switch (key) { case 27: //Escape key exit(0); //Exit the program } } //Initializes 3D rendering void initRendering() { //Makes 3D drawing work when something is in front of something else glEnable(GL_DEPTH_TEST); } //Called when the window is resized void handleResize(int w, int h) { //Tell OpenGL how to convert from coordinates to pixel values glViewport(0, 0, w, h); glMatrixMode(GL_PROJECTION); //Switch to setting the camera perspective //Set the camera perspective glLoadIdentity(); //Reset the camera gluPerspective(45.0, //The camera angle (double)w / (double)h, //The width-to-height ratio 1.0, //The near z clipping coordinate 200.0); //The far z clipping coordinate } //Draws the 3D scene void drawScene() { //Clear information from last draw glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); glLoadIdentity(); //Reset the drawing perspective glPolygonMode(GL_FRONT_AND_BACK, GL_FILL); glBegin(GL_POLYGON); //Begin quadrilateral coordinates //Trapezoid glColor3f(255,0,0); for(int i = 0; i < 6; ++i) { glVertex2d(sin(i/6.0*2* 3.1415), cos(i/6.0*2* 3.1415)); } glEnd(); //End quadrilateral coordinates glutSwapBuffers(); //Send the 3D scene to the screen } int main(int argc, char** argv) { //Initialize GLUT glutInit(&argc, argv); glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGBA | GLUT_DEPTH); glutInitWindowSize(400, 400); //Set the window size //Create the window glutCreateWindow("Basic Shapes - videotutorialsrock.com"); initRendering(); //Initialize rendering //Set handler functions for drawing, keypresses, and window resizes glutDisplayFunc(drawScene); glutKeyboardFunc(handleKeypress); glutReshapeFunc(handleResize); glutMainLoop(); //Start the main loop. glutMainLoop doesn't return. return 0; //This line is never reached } How can I make it so that a polygon of 0,0 10,0 10,10 0,10 defines a polygon starting at the top left of the screen and is a width and height of 10 pixels? Thanks

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• Which is the "best" data access framework/approach for C# and .NET?

  - by Frans

  (EDIT: I made it a community wiki as it is more suited to a collaborative format.) There are a plethora of ways to access SQL Server and other databases from .NET. All have their pros and cons and it will never be a simple question of which is "best" - the answer will always be "it depends". However, I am looking for a comparison at a high level of the different approaches and frameworks in the context of different levels of systems. For example, I would imagine that for a quick-and-dirty Web 2.0 application the answer would be very different from an in-house Enterprise-level CRUD application. I am aware that there are numerous questions on Stack Overflow dealing with subsets of this question, but I think it would be useful to try to build a summary comparison. I will endeavour to update the question with corrections and clarifications as we go. So far, this is my understanding at a high level - but I am sure it is wrong... I am primarily focusing on the Microsoft approaches to keep this focused. ADO.NET Entity Framework Database agnostic Good because it allows swapping backends in and out Bad because it can hit performance and database vendors are not too happy about it Seems to be MS's preferred route for the future Complicated to learn (though, see 267357) It is accessed through LINQ to Entities so provides ORM, thus allowing abstraction in your code LINQ to SQL Uncertain future (see Is LINQ to SQL truly dead?) Easy to learn (?) Only works with MS SQL Server See also Pros and cons of LINQ "Standard" ADO.NET No ORM No abstraction so you are back to "roll your own" and play with dynamically generated SQL Direct access, allows potentially better performance This ties in to the age-old debate of whether to focus on objects or relational data, to which the answer of course is "it depends on where the bulk of the work is" and since that is an unanswerable question hopefully we don't have to go in to that too much. IMHO, if your application is primarily manipulating large amounts of data, it does not make sense to abstract it too much into objects in the front-end code, you are better off using stored procedures and dynamic SQL to do as much of the work as possible on the back-end. Whereas, if you primarily have user interaction which causes database interaction at the level of tens or hundreds of rows then ORM makes complete sense. So, I guess my argument for good old-fashioned ADO.NET would be in the case where you manipulate and modify large datasets, in which case you will benefit from the direct access to the backend. Another case, of course, is where you have to access a legacy database that is already guarded by stored procedures. ASP.NET Data Source Controls Are these something altogether different or just a layer over standard ADO.NET? - Would you really use these if you had a DAL or if you implemented LINQ or Entities? NHibernate Seems to be a very powerful and powerful ORM? Open source Some other relevant links; NHibernate or LINQ to SQL Entity Framework vs LINQ to SQL

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• Weird Datagrid / paint behaviour

  - by Shane.C

  The scenario: A method sends out a broadcast packet, and returned packets that are validated are deemed okay to be added as a row in my datagrid (The returned packets are from devices i want to add into my program). So for each packet returned, containing information about a device, i create a new row. This is done by first sending packets out, creating rows and adding them to a list of rows that are to be added, and then after 5 seconds (In which case all packets would have returned by then) i add the rows. Here's a few snippets of code. Here for each returned packet, i create a row and add it to a list; DataRow row = DGSource.NewRow(); row["Name"] = deviceName; row["Model"] = deviceModel; row["Location"] = deviceLocation; row["IP"] = finishedIP; row["MAC"] = finishedMac; row["Subnet"] = finishedSubnet; row["Gateway"] = finishedGateway; rowsToAdd.Add(row); Then when the timer elapses; void timerToAddRows_Elapsed(object sender, System.Timers.ElapsedEventArgs e) { timerToAddRows.Enabled = false; try { int count = 0; foreach (DataRow rowToAdd in rowsToAdd) { DGSource.Rows.Add(rowToAdd); count++; } rowsToAdd.Clear(); DGAutoDevices.InvokeEx(f => DGAutoDevices.Refresh()); lblNumberFound.InvokeEx(f => lblNumberFound.Text = count + " new devices found."); } catch { } } So at this point, each row has been added, and i call the re paint, by doing refresh. (Note: i've also tried refreshing the form itself, no avail). However, when the datagrid shows the rows, the scroll bar / datagrid seems to have weird behavour..for example i can't highlight anything with clicks (It's set to full row selection), and the scroll bar looks like so; Calling refresh doesn't work, although if i resize the window even 1 pixel, or minimize and maximise, the problem is solved. Other things to note : The method that get's the packets and adds the rows to the list, and then from the list to the datagrid runs in it's own thread. Any ideas as to something i might be missing here?

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• Is there anything wrong with my texture loading method ?

  - by José Joel.

  I'm a noob in openGL and trying to learn as much as possible. I'm using this method to load my openGL textures, loading every .png as RGBA4444. I'm doing anything incorrect ? - (void)loadTexture:(NSString*)nombre { CGImageRef textureImage =[UIImage imageWithContentsOfFile:[[NSBundle mainBundle] pathForResource:nombre ofType:nil]].CGImage; if (textureImage == nil) { NSLog(@"Failed to load texture image"); return; } textureWidth = NextPowerOfTwo(CGImageGetWidth(textureImage)); textureHeight = NextPowerOfTwo(CGImageGetHeight(textureImage)); imageSizeX= CGImageGetWidth(textureImage); imageSizeY= CGImageGetHeight(textureImage); GLubyte *textureData = (GLubyte *)calloc(1,textureWidth * textureHeight * 4); // Por 4 pues cada pixel necesita 4 bytes, RGBA CGContextRef textureContext = CGBitmapContextCreate(textureData, textureWidth,textureHeight,8, textureWidth * 4,CGImageGetColorSpace(textureImage),kCGImageAlphaPremultipliedLast ); CGContextDrawImage(textureContext, CGRectMake(0.0, 0.0, (float)textureWidth, (float)textureHeight), textureImage); //Convert "RRRRRRRRRGGGGGGGGBBBBBBBBAAAAAAAA" to "RRRRGGGGBBBBAAAA" void *tempData = malloc(textureWidth * textureHeight * 2); unsigned int* inPixel32 = (unsigned int*)textureData; unsigned short* outPixel16 = (unsigned short*)tempData; for(int i = 0; i < textureWidth * textureHeight ; ++i, ++inPixel32) *outPixel16++ = ((((*inPixel32 >> 0) & 0xFF) >> 4) << 12) | // R ((((*inPixel32 >> 8) & 0xFF) >> 4) << 8) | // G ((((*inPixel32 >> 16) & 0xFF) >> 4) << 4) | // B ((((*inPixel32 >> 24) & 0xFF) >> 4) << 0); // A free(textureData); textureData = tempData; CGContextRelease(textureContext); glGenTextures(1, &textures[0]); glBindTexture(GL_TEXTURE_2D, textures[0]); glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, textureWidth, textureHeight, 0, GL_RGBA, GL_UNSIGNED_SHORT_4_4_4_4 , textureData); free(textureData); glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR); glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR); } And this is my dealloc method: - (void)dealloc { glDeleteTextures(1,textures); [super dealloc]; }

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