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  • Which OpenGL functions are not GPU-accelerated?

    - by Xavier Ho
    I was shocked when I read this (from the OpenGL wiki): glTranslate, glRotate, glScale Are these hardware accelerated? No, there are no known GPUs that execute this. The driver computes the matrix on the CPU and uploads it to the GPU. All the other matrix operations are done on the CPU as well : glPushMatrix, glPopMatrix, glLoadIdentity, glFrustum, glOrtho. This is the reason why these functions are considered deprecated in GL 3.0. You should have your own math library, build your own matrix, upload your matrix to the shader. For a very, very long time I thought most of the OpenGL functions use the GPU to do computation. I'm not sure if this is a common misconception, but after a while of thinking, this makes sense. Old OpenGL functions (2.x and older) are really not suitable for real-world applications, due to too many state switches. This makes me realise that, possibly, many OpenGL functions do not use the GPU at all. So, the question is: Which OpenGL function calls don't use the GPU? I believe knowing the answer to the above question would help me become a better programmer with OpenGL. Please do share some of your insights.

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  • Calling NSFetchedResultsController & CoreData experts

    - by JK
    I am having a few nagging issues with NSFetchedResultsController and CoreData, any of which I would be very grateful to get help on. Issue 1 - Updates: I update my store on a background thread which results in certain rows being delete, inserted or updated. The changes are merged into the context on the main thread using the "mergeChangesFromContextDidSaveNotification:" method. Inserts and deletes are updated properly, but updates are not (e.g. the cell label is not updated with the change) although I have confirmed the updates to come through the contextDidSaveNotifcation, exactly like the inserts and deleted. My current workaround is to temporarily change the staleness interval of the context to 0, but this does not seem like the ideal solution. Issue 2 - Deleting objects: My fetch batch size is 20. If an object is deleted by the background thread which is in the first 20 rows, everything works fine. But if the object is after the first 20 rows and the table is scrolled down, a "CoreData could not fulfill a fault" error is raised. I have tried resaving the context and reperforming the frc fetch - all to no avail. Note: In this scenario, the frc delegate method "didChangeObject...." is not called for the delete - I assume this is because the object in question had not been faulted at that time (as it is was outside the initial fetch range). But for some reason, the context still thinks the object is around, although is has been deleted from the store. Issue 3 - Deleting sections : When the deletion of a row leads to the deletion of a section, I have gotten the "invalid number of rows in section???" error. I have worked around this by removing the "reloadSection" line from the NSFetchedResultsChangeMove: section and replacing it with "[tableView insertRowsAtIndexPaths...." This seems to work, but once again, I am not sure if this is the best solution. Any help would be greatly appreciated. Thank you!

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  • How to draw a single point with .Net?

    - by SoMoS
    Hello, this should be pretty simple but I don't get it. How can I draw a single point in .Net? If I use g.DrawLine(Black,0,0,0,0) nothing is drawn and if I use g.DrawLine(Black,0,0,1,0) a line with 2 dots is used. The same happens with g.DrawRectangle. This has me intrigued. Thanks in advance.

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  • Returning a users lat lng as a string iPhone

    - by Joshmattvander
    Is there a way to return the users location as a string from a model? I have a model thats job is to download same JSON data from a web service. When sending in my request I need to add ?lat=LAT_HERE&lng=LNG_HERE to the end of the string. I have seen tons of examples using the map or constantly updating a label. But I cant find out how to explicitly return the lat and lng values. Im only 2 days into iPhone dev so go easy on me :)

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  • Pretty Pixel-level Picture Painting, Programatically

    - by dreeves
    My mac laptop has 1,024,000 pixels. What's the simplest way to turn my display completely black and go nuts with writing little programs to twiddle pixels to my heart's delight? To make it more concrete, say I wanted to implement the Chaos Game to draw a Sierpinski triangle, at the pixel level, with nothing else on the screen. What are ways to do that?

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  • Get Highest Res Favicon

    - by Jeremy
    I'm making a website that needs to dynamically obtain the favicon of sites upon request. I've found a few api's that can accomplish this fairly well, and so far I'm liking http://www.fvicon.com/. The final image for my website will be 64x64px, and some websites such as Google and Wordpress have nice images of this size that are easily retrieved via this api. Though, of course, most websites only have a 16x16 favicon image and scaling that image to 64x64 has very bad quality loss. Examples: (high res) http://a.fvicon.com/wordpress.com?format=png&width=64&height=64 (low res) http://a.fvicon.com/yahoo.com?format=png&width=64&height=64 Keeping this in mind, I'm planning on somehow determining whether a high-res image is available and, if so, the website will use this image. If not, I want to use a pre-made 64x64 icon with the smaller icon layered over it. What I'm having trouble with is determining if there is a high res favicon available or not. Also, I'm curious if there's a better approach to this situation. I'd rather not use smaller images (64x64 works out really well for this project). The lowest res I'm willing to drop to is 48x48 but even then there will be a significant quality loss for scaling up 16x16 favicons. Any ideas? If you need any more information I will gladly provide it. Thank you!

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  • Can XCode draw the call graph of a program?

    - by Werner
    Hi, I am new to Mac OSX, and I wonder if Xcode can generate , for a given C++ source code, the call graph of the program in a visual way. I also wonder if for each function, and after a run, whether it can also print the %time spent on the function If so, I would thank really some links with tutorials or info, after googling I did not find anything relevant Thanks

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  • iPhone Development - CoreData runtime error

    - by Mustafa
    I'm facing a strange CoreData issue. Here's the log: 2010-04-07 15:59:36.913 MyProject[263:207] <MyEntity: 0x180370> (entity: MyEntity; id: 0x17e890 <x-coredata://0F55C533-41BD-4F09-9CCA-0CB304CAB065/MyEntity/p380> ; data: <fault>) 2010-04-07 15:59:36.918 MyProject[263:207] *** Terminating app due to uncaught exception 'NSObjectInaccessibleException', reason: 'The NSManagedObject with ID:0x17e890 <x-coredata://0F55C533-41BD-4F09-9CCA-0CB304CAB065/MyEntity/p380> has been invalidated.' I have a hierarchy of UITableViewControllers that use NSFetchedResultsController to populate the table, and when a particular row is selected, the detail view is shown. UITableView (MyMainEntity) UITableView (MyEntity) UITableView (MyEntity) detail view Both MyMainEntity UITableView and MyEntity UITableView use NSFetchedResultsController to show the records. Sometimes it crashes when i'm scrolling the tableView, and sometimes it crashes when i try to open the detail view. I can navigate to the MyEntity detail view multiple times before application crashes. What does this error mean? and how can i fix it!?

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  • SVG Animation in Python? - Any options other than Things! 0.4?

    - by ThantiK
    I recently gave my daughter some time on the computer, and she really likes a program called 'BabySmash!', and I also have another program that came with a keyboard attachment called 'Laugh, Smile & Learn' from playschool I think. I'm not a python guru by any stretch of the imagination and I kind of have it in my head that I want to create some sort of program in the spirit of these two, with vector animation and sounds. Thing is, it doesn't look like there are many options for vector animation in python. I found a library called Things! 0.4, but it's lacking in-depth documentation and seems to be more of an experiment in vector animation rather than a full blown solution. Are there any options that I'm not immediately finding? What other animation-libraries do you recommend? Even if the library isn't vector-based, ease of use is probably the strongest factor in my use.

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  • How to animate line-drawing in iPhone development?

    - by david
    I have been searching around, but there seems no good answer for this simple question. So I am asking again: how to animate line-drawing in iphone dev? Basically what I want is something like this: @implementation MyUIView - (void) triggerLineDrawing: (CGPathRef) path { ... // animate line drawing here } Can it be done?

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  • Repeating animations using the Stop Selector

    - by Tiago
    I'm trying to repeat an animation until a certain condition is met. Something like this: - (void) animateUpdate { if (inUpdate) { [UIView beginAnimations:nil context:NULL]; [UIView setAnimationDuration:2.0]; [UIView setAnimationDelegate: self]; [UIView setAnimationDidStopSelector: @selector(animateUpdate)]; button.transform = CGAffineTransformMakeRotation( M_PI ); [UIView commitAnimations]; } } This will run the first time, but it won't repeat. The selector will just be called until the application crashes. How should I do this? Thanks.

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  • Blur CALayer's Superlayer

    - by eaigner
    Hi. I've got a CALayer and a sublayer in it. What i want to achieve is a blur of the superlayer (the area under the sublayer), just like the standard sheets do it. I've tried to set a .compositingFilter on the sublayer but this doesn't seem to work. Any ideas how to solve this?

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  • How to -accurately- measure size in pixels of text being drawn on a canvas by drawTextOnPath()

    - by Nick
    I'm using drawTextOnPath() to display some text on a Canvas and I need to know the dimensions of the text being drawn. I know this is not feasible for paths composed of multiple segments, curves, etc. but my path is a single segment which is perfectly horizontal. I am using Paint.getTextBounds() to get a Rect with the dimensions of the text I want to draw. I use this rect to draw a bounding box around the text when I draw it at an arbitrary location. Here's some simplified code that reflects what I am currently doing: // to keep this example simple, always at origin (0,0) public drawBoundedText(Canvas canvas, String text, Paint paint) { Rect textDims = new Rect(); paint.getTextBounds(text,0, text.length(), textDims); float hOffset = 0; float vOffset = paint.getFontMetrics().descent; // vertically centers text float startX = textDims.left; / 0 float startY = textDims.bottom; float endX = textDims.right; float endY = textDims.bottom; path.moveTo(startX, startY); path.lineTo(endX, endY); path.close(); // draw the text canvas.drawTextOnPath(text, path, 0, vOffset, paint); // draw bounding box canvas.drawRect(textDims, paint); } The results are -close- but not perfect. If I replace the second to last line with: canvas.drawText(text, startX, startY - vOffset, paint); Then it works perfectly. Usually there is a gap of 1-3 pixels on the right and bottom edges. The error seems to vary with font size as well. Any ideas? It's possible I'm doing everything right and the problem is with drawTextOnPath(); the text quality very visibly degrades when drawing along paths, even if the path is horizontal, likely because of the interpolation algorithm or whatever its using behind the scenes. I wouldnt be surprised to find out that the size jitter is also coming from there.

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  • animating adding/removing layers on iPhone

    - by magesteve
    On the iPhone, when you add a sub layer to a visible view's layer, using either -addSublayer: or -removeFromSuperlayer, shouldn't that sub layer appear or disappear in an animated manner (ie. fade in or fade out gradually)? My program animates using layers (not views). When I change a property of a layer like position or image content, then the change does animate (layer streaks around it's parent layer, the layer fades from the old image to the new image), so I obviously have the layers & view setup correctly. However, when I add or remove a sub layer, the change occurs instantly; there is no animation. Reading the references, it says that if the layer is visible, the sub layer should animate when adder or removed. What am I doing wrong? Has anyone had a similar problem, and was able to find a solution? Thank you, Steve Sheets

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  • Can two managed object context share one single persistent store coordinator?

    - by mystify
    Example: I have one persistent store coordinator which uses one single persistent store. Now there are two managed object contexts, and both want to use the same persistent store. Could both simply use the same persistent store coordinator, or would I have to create two instances of NSPersistentStoreCoordinator? And if I had to, then: Would I also have to create two NSPersistentStore instances?

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  • quartz2d translating the origin

    - by qwertyp96
    My understanding of quartz2d is that the code CGContextTranslateCTM(context, x, y); translates the coordinate system. I have a quartz2d view with lots of shapes on it, and the user needs to be able to pan around and zoom it. However, when using the CGContextScaleCTM(context, scaleX, scaleY); code, everything scales around the origin, not the center of the viewpoint the user is viewing. My solution to this was to use the following code: CGContextRef context = UIGraphicsGetCurrentContext(); CGContextTranslateCTM(context, 512.0+offset.x, 384.0+offset.y); //(512, 384) is the center of the iPad screen CGContextScaleCTM(context, scale, scale); You can translate around fine, but things still scale into the corner. What's wrong? EDIT: Oh. Wow. Duh. If you move the origin, the shapes move too, so you can't move it relative to the shapes. Now I know what's wrong, but how do I do that?(move the origin independently of the shapes)

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  • BlackBerry - Convert EncodedImage to byte []

    - by user324884
    I am using below code where i don't want to use JPEGEncodedImage.encode because it increases the size. So I need to directly convert from EncodedImage to byte array. FileConnection fc= (FileConnection)Connector.open(name); is=fc.openInputStream(); byte[] ReimgData = IOUtilities.streamToBytes(is); EncodedImage encode_image = EncodedImage.createEncodedImage(ReimgData, 0, (int)fc.fileSize()); encode_image = sizeImage(encode_image, (int)maxWidth,(int)maxHeight); JPEGEncodedImage encoder=JPEGEncodedImage.encode(encode_image.getBitmap(),50); ReimgData=encoder.getData(); is.read(ReimgData); HttpMultipartRequest( content[0], content[1], content[2], params, "image",txtfile.getText(), "image/jpeg", ReimgData );

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  • When using Direct3D, how much math is being done on the CPU?

    - by zirgen
    Context: I'm just starting out. I'm not even touching the Direct3D 11 API, and instead looking at understanding the pipeline, etc. From looking at documentation and information floating around the web, it seems like some calculations are being handled by the application. That, is, instead of simply presenting matrices to multiply to the GPU, the calculations are being done by a math library that operates on the CPU. I don't have any particular resources to point to, although I guess I can point to the XNA Math Library or the samples shipped in the February DX SDK. When you see code like mViewProj = mView * mProj;, that projection is being calculated on the CPU. Or am I wrong? If you were writing a program, where you can have 10 cubes on the screen, where you can move or rotate cubes, as well as viewpoint, what calculations would you do on the CPU? I think I would store the geometry for the a single cube, and then transform matrices representing the actual instances. And then it seems I would use the XNA math library, or another of my choosing, to transform each cube in model space. Then get the coordinates in world space. Then push the information to the GPU. That's quite a bit of calculation on the CPU. Am I wrong? Am I reaching conclusions based on too little information and understanding? What terms should I Google for, if the answer is STFW? Or if I am right, why aren't these calculations being pushed to the GPU as well?

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