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  • Computer Graphics: Principles and Practice in C ( in Python? )

    - by user29163
    I am attending a Computer graphics course after the summer. I have read lots of good things about the book "Computer Graphics: Principles and Practice in C" for people who are willing to put in some work. My school does not focus on C/C++ until next year, so I have decided to learn Python this summer and get good at Python this following year. How language dependent is this book? Can I work through it in Python?

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  • Double Free inside of a destructor upon adding to a vector

    - by Shawn B
    Hey, I am working on a drum machine, and am having problems with vectors. Each Sequence has a list of samples, and the samples are ordered in a vector. However, when a sample is push_back on the vector, the sample's destructor is called, and results in a double free error. Here is the Sample creation code: class XSample { public: Uint8 Repeat; Uint8 PlayCount; Uint16 Beats; Uint16 *Beat; Uint16 BeatsPerMinute; XSample(Uint16 NewBeats,Uint16 NewBPM,Uint8 NewRepeat); ~XSample(); void GenerateSample(); void PlaySample(); }; XSample::XSample(Uint16 NewBeats,Uint16 NewBPM,Uint8 NewRepeat) { Beats = NewBeats; BeatsPerMinute = NewBPM; Repeat = NewRepeat-1; PlayCount = 0; printf("XSample Construction\n"); Beat = new Uint16[Beats]; } XSample::~XSample() { printf("XSample Destruction\n"); delete [] Beat; } And the 'Dynamo' code that creates each sample in the vector: class XDynamo { public: std::vector<XSample> Samples; void CreateSample(Uint16 NewBeats,Uint16 NewBPM,Uint8 NewRepeat); }; void XDynamo::CreateSample(Uint16 NewBeats,Uint16 NewBPM,Uint8 NewRepeat) { Samples.push_back(XSample(NewBeats,NewBPM,NewRepeat)); } Here is main(): int main() { XDynamo Dynamo; Dynamo.CreateSample(4,120,2); Dynamo.CreateSample(8,240,1); return 0; } And this is what happens when the program is run: Starting program: /home/shawn/dynamo2/dynamo [Thread debugging using libthread_db enabled] XSample Construction XSample Destruction XSample Construction XSample Destruction *** glibc detected *** /home/shawn/dynamo2/dynamo: double free or corruption (fasttop): 0x0804d008 *** However, when the delete [] is removed from the destructor, the program runs perfectly. What is causing this? Any help is greatly appreciated.

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  • Vector insert() causes program to crash

    - by wrongusername
    This is the first part of a function I have that's causing my program to crash: vector<Student> sortGPA(vector<Student> student) { vector<Student> sorted; Student test = student[0]; cout << "here\n"; sorted.insert(student.begin(), student[0]); cout << "it failed.\n"; ... It crashes right at the sorted part because I can see "here" on the screen but not "it failed." The following error message comes up: Debug Assertion Failed! (a long path here...) Expression: vector emplace iterator outside range For more information on how your program can cause an assertion failure, see the Visual C++ documentation on asserts. I'm not sure what's causing the problem now, since I have a similar line of code elsewhere student.insert(student.begin() + position(temp, student), temp); that does not crash (where position returns an int and temp is another declaration of a struct Student). What can I do to resolve the problem, and how is the first insert different from the second one?

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  • Get location of element you just pushed into vector C++

    - by Satchmo Brown
    I am curious about how pushing back into a vector works. I want a way to push back an element and then be able to add it's location in the vector to a double array serving as a type of map. Something like this: // Create a bomb Bomb b; b.currentTime = SDL_GetTicks(); b.explodeTime = SDL_GetTicks() + 3000; b.owner = player; b.power = 2; b.x = x; b.y = y; bombVec.push_back(b); bombs[y][x] = THIS_IS_WHAT_I_WANT; This way when I explode the bomb, I can check the map and then have an ID in the vector to deal with. Every non bomb square will have a -1. Also, just curious. Imagine I have 3 elements in a vector. I delete the second one and then add another. Does the new element go in the same location as the one that was deleted? Thanks!

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  • Loading data from file to Vector structure

    - by owca
    I'm trying to parse through fixed-width formatted file extracting x,y values of points from it, and then storing them in int[] array inside a Vector. Text file looks as follows : 0006 0015 0125 0047 0250 0131 That's the code : Vector<int[]> vc = new Vector<int[]>(); try { BufferedReader file = new BufferedReader(new FileReader("myfile.txt")); String s; int[] vec = new int[2]; while ((s = file.readLine()) != null) { vec[0] = Integer.parseInt(s.substring(0, 4).trim()); vec[1] = Integer.parseInt(s.substring(5, 8).trim()); vc.add(vec); } file.close(); } catch (IOException e) { } for(int i=0; i<vc.size(); i++){ for(int j=0; j<2; j++){ System.out.println(vc.elementAt(i)[j]); } } But the output shows only last line. 250 131 250 131 250 131 Should I somehow use Vector.nextElement() here to get all my data ?

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  • C++ std::vector memory/allocation

    - by aaa
    from a previous question about vector capacity, http://stackoverflow.com/questions/2663170/stdvector-capacity-after-copying, Mr. Bailey said: In current C++ you are guaranteed that no reallocation occurs after a call to reserve until an insertion would take the size beyond the value of the previous call to reserve. Before a call to reserve, or after a call to reserve when the size is between the value of the previous call to reserve and the capacity the implementation is allowed to reallocate early if it so chooses. So, if I understand correctly, in order to assure that no relocation happens until capacity is exceeded, I must do reserve twice? can you please clarify it? I am using vector as a memory stack like this: std::vector<double> memory; memory.reserve(size); memory.insert(memory.end(), matrix.data().begin(), matrix.data().end()); // smaller than size size_t offset = memory.size(); memory.resize(memory.capacity(), 0); I need to guarantee that relocation does not happen in the above. thank you. ps: I would also like to know if there is a better way to manage memory stack in similar manner other than vector

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  • Where should I plug in my monitor -- Motherboard or Graphics card?

    - by Jeremy White
    Assuming I am using the following equipment... motherboard with HDMI/DVI & no embedded graphics discrete graphics card (nVidia or ATI) on PCI-E slot Intel CPU with integrated graphics ...where should I plug my monitor into the computer? Presumably, I'll get the fastest speed on games connected directly to the graphics card. But there is also power savings when connecting to the motherboard and accessing the Intel on-board graphics. I've read that some motherboards can switch automatically between the Intel graphics and discrete graphics. Is that something that works well, and where do I connect the monitor to enable that?

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  • Understanding normal maps on terrain

    - by JohnB
    I'm having trouble understanding some of the math behind normal map textures even though I've got it to work using borrowed code, I want to understand it. I have a terrain based on a heightmap. I'm generating a mesh of triangles at load time and rendering that mesh. Now for each vertex I need to calculate a normal, a tangent, and a bitangent. My understanding is as follows, have I got this right? normal is a unit vector facing outwards from the surface of the triangle. For a vertex I take the average of the normals of the triangles using that vertex. tangent is a unit vector in the direction of the 'u' coordinates of the texture map. As my texture u,v coordinates follow the x and y coordinates of the terrain, then my understanding is that this vector is simply the vector along the surface in the x direction. So should be able to calculate this as simply the difference between vertices in the x direction to get a vector, (and normalize it). bitangent is a unit vector in the direction of the 'v' coordinates of the texture map. As my texture u,v coordinates follow the x and y coordinates of the terrain, then my understanding is that this vector is simply the vector along the surface in the y direction. So should be able to calculate this as simply the difference between vertices in the y direction to get a vector, (and normalize it). However the code I have borrowed seems much more complicated than this and takes into account the actual values of u, and v at each vertex which I don't understand the need for as they increase in exactly the same direction as x, and y. I implemented what I thought from above, and it simply doesn't work, the normals are clearly not working for lighting. Have I misunderstood something? Or can someone explain to me the physical meaning of the tangent and bitangent vectors when applied to a mesh generated from a hightmap like this, when u and v texture coordinates map along the x and y directions. Thanks for any help understanding this.

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  • Sudden "No Signal" in HDMI-DVI connection

    - by nazikus
    Yesterday I have connected external display Asus VW192C to my laptop Dell XPS 14-L421X via HDMI-to-DVI-D cable. And it worked perfectly fine from start. The day after, Asus screen went blank showing "No signal". Every time I connection/disconnection cable or power off/on the display it says "No signal". And I didn't change any system configurations meanwhile. To troubleshoot the problem, I have tried to connect laptop to TV (hdmi-to-hdmi) - it was fine. I've tried to connect a different laptop to the display via the same cable - worked fine as well. So its obviously something on system level, either Windows or graphics drivers. Also it seems that Windows still see the external display (I can move mouse pointer away from the main screen in Extended mode), but there's just no signal. Any ideas? What else to try? PS. My laptop has 2 graphics cards - GeForce 630M and Intel HD 4000 using NVidia Optimus technology. I have updated to latest Intel and NVidia drivers, still didn't help. PPS. Although I shouldn't have updated (from Intel support): "our Intel generic graphics drivers from the Intel website do not support using both Intel Graphics 4000 and NVidia GeForece GT630M". Nevertheless, it should not affect connectivity to additional display.

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  • android saveinstance saving vector datatypes

    - by Javadid
    hi friends, I am making an application which is currently working perfectly but with only 1 problem... As we all know that the activity is destroyed and recreated when user changes the orientation of the phone... my activity needs to save a vector full of objects wen the activity is recreated... i checked the OnSaveInstance() method and found that there is no way a vector can be stored... Does any1 have a suggestion for storing vector so that i can retrieve it on recreation of Activity??? Any help will be appreciated... Thanx...

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  • Sorting a vector of (double precision) reals and obtain their order

    - by Philipp
    Hello everyone, in C++ would like to sort a lengthy (2^20) vector of reals, obviously sort() does the trick. Having used R before I was used to the nice order() function which yields the permutation that leads to the sorted vector. Probably someone has done this in C++, maybe it's just my weak google-Fu that prevents me from finding it. And yeah, obivously my C++ newbness could stop me from spotting something straightforward. Example: x = {24, 55, 22, 1} then the permutation perm = {3, 2, 0, 1} maps the original x to the sorted x in ascending order. I can probably implement some bubble sort which does not only sort x but performs the same transpositions on the vector {0,1,2,...} and outputs both, but I believe someone must have thought about it and especially have done it efficiently. Thank you very much, Philipp

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  • Boost::Container::Vector with Enum Template Argument - Not Legal Base Class

    - by CuppM
    Hi, I'm using Visual Studio 2008 with the Boost v1.42.0 library. If I use an enum as the template argument, I get a compile error when adding a value using push_back(). The compiler error is: 'T': is not a legal base class and the location of the error is move.hpp line 79. #include <boost/interprocess/containers/vector.hpp> class Test { public: enum Types { Unknown = 0, First = 1, Second = 2, Third = 3 }; typedef boost::container::vector<Types> TypesVector; }; int main() { Test::TypesVector o; o.push_back(Test::First); return 0; } If I use a std::vector instead it works. And if I resize the Boost version first and then set the values using the [] operator it also works. Is there some way to make this work using push_back()?

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  • Method for exporting drawn flash/flex UIComponent to vector based print file

    - by eshowcase
    Hi, I am creating a flex application where I am using the built in graphics package of flex 3 to draw shapes and things to a UIComponent. I want to be able to export this vector image UIComponent to a vector based file, pdf, eps etc. Are there any tools, libraries, or methods for doing so? I looked at AlivePDF - which works very slick, but its output is effectively a snapshot of the UIComponent drawn out as a bitmap to the PDF. I want true vector output, as this image is for print, needs to be able to scale and be color correct. I read somewhere that it may be possible with Adobe Live Cycle, but in looking at the documentation I'm not sure how to use it. Another possibility is to submit the final image parameters to a server-side PHP script that would re-generate the image in SVG format. But as I understand SVG is not ideal for print, and this is lots of extra work. Any thoughts, ideas, methods? Thanks!

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  • vector segmentation fault

    - by user1849298
    I have a problem with the segmentation fault. Look: #include<fstream> using namespace std; int main(){ int n,i,vector[10001],vectorcopy[10001]; ifstream in("program.in"); ofstream out("program.out"); in>>n; for(i=1;i<=n;i++){ in>>vector[i]; vectorcopy[i]=vector[i]; } return 0;} And the debugger says: Program recived signal SIGSEGV, Segmentation fault Please, tell me what to do!

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  • c++ Sorting a vector based on values of other vector, or what's faster?

    - by pollux
    Hi, There are a couple of other posts about sorting a vector A based on values in another vector B. Most of the other answers tell to create a struct or a class to combine the values into one object and use std::sort. Though I'm curious about the performance of such solutions as I need to optimize code which implements bubble sort to sort these two vectors. I'm thinking to use a vector<pair<int,int>> and sort that. I'm working on a blob-tracking application (image analysis) where I try to match previously tracked blobs against newly detected blobs in video frames where I check each of the frames against a couple of previously tracked frames and of course the blobs I found in previous frames. I'm doing this at 60 times per second (speed of my webcam). Any advice on optimizing this is appreciated. The code I'm trying to optimize can be shown here: http://code.google.com/p/projectknave/source/browse/trunk/knaveAddons/ofxBlobTracker/ofCvBlobTracker.cpp?spec=svn313&r=313 Thanks

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  • Counting Values in R Vector

    - by GTyler
    I have a large vector of percentages (0-100) and I am trying to count how many of them are in specific 20% buckets (<20, 20-40, 40-60,60-80,80-100). The vector has length 129605 and there are no NA values. Here's my code: x<-c(0,0,0,0,0) for(i in 1: length(mail_return)) { if (mail_return[i]<=20) { x[1] = x[1] + 1 } if (mail_return[i]>20 && mail_return[i]<=40) { x[2] = x[2] + 1 } if (mail_return[i]>40 && mail_return[i]<=60) { x[3] = x[3] + 1 } if (mail_return[i]>60 && mail_return[i]<=80) { x[4] = x[4] + 1 } else { x[5] = x[5] + 1 } } But sum(x) is giving me length 133171. Shouldn't it be the length of the vector, 129605? What's wrong?

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  • Java: How to store Vector<String[]> in XML (or save in any other way)

    - by hatboysam
    Basically I have a proof-of-concept application that is a digital recipe book. Each Recipe is an object and each object has, among other fields, a Vector containing arrays. The Vector is the list of all ingredients in the Recipe while each ingredient has an array showing the name of the ingredient, the amount, and the unit for that amount. I want to save each Recipe to XML so that they can be accessed by the user. How can I store a Vector of String arrays in XML or any other sort of file so that it can later be recalled and accessed?

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  • C++ Vector of vectors

    - by xbonez
    I have a class header file called Grid.h that contains the following 2 private data object: vector<int> column; vector<vector<int>> row; And a public method whose prototype in Grid.h is such: int getElement (unsigned int& col, unsigned int& row); The definition of above mentioned function is defined as such in Grid.cpp: int getElement (unsigned int& col, unsigned int& row) { return row[row][col] ; } When I run the program, I get this error: error C2109: subscript requires array or pointer type Whats going wrong?

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  • C++ vector that *doesn't* initialize its members?

    - by Mehrdad
    I'm making a C++ wrapper for a piece of C code that returns a large array, and so I've tried to return the data in a vector<unsigned char>. Now the problem is, the data is on the order of megabytes, and vector unnecessarily initializes its storage, which essentially turns out to cut down my speed by half. How do I prevent this? Or, if it's not possible -- is there some other STL container that would avoid such needless work? Or must I end up making my own container? (Pre-C++11) Note: I'm passing the vector as my output buffer. I'm not copying the data from elsewhere.

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  • How do I fix the HDMI/DVI display output with Intel HD 4000 Graphics in 12.04?

    - by YumYumYum
    I have an Alienware Dell PC with Intel HD 4000 Graphics (Ivy Bridge) as verified by the output of lspci | grep VGA posted below. 00:02.0 VGA compatible controller: Intel Corporation Ivy Bridge Graphics Controller (rev 09) The PC only has HDMI and DVI display outputs and using the HDMI output I am only being offered abnormal resolutions. As you can see below it does not even list HDMI1 or DVI1 but just only a fallback. $ export DISPLAY=:0.0 && xrandr xrandr: Failed to get size of gamma for output default Screen 0: minimum 640 x 480, current 1360 x 768, maximum 1360 x 768 default connected 1360x768+0+0 0mm x 0mm 1360x768 0.0* 1024x768 0.0 800x600 0.0 640x480 0.0 How can I fix this? Does it just need to be configured differently or will I need to use a newer kernel (as Intel Graphics drivers are included in the kernel)? Follow up: kernel to latest Step 1: Go to: http://kernel.ubuntu.com/~kernel-ppa/mainline/ Go to last: http://kernel.ubuntu.com/~kernel-ppa/mainline/v3.6-rc3-quantal/ Download: http://kernel.ubuntu.com/~kernel-ppa/mainline/v3.6-rc3-quantal/linux-headers-3.6.0-030600rc3-generic_3.6.0-030600rc3.201208221735_amd64.deb http://kernel.ubuntu.com/~kernel-ppa/mainline/v3.6-rc3-quantal/linux-headers-3.6.0-030600rc3_3.6.0-030600rc3.201208221735_all.deb http://kernel.ubuntu.com/~kernel-ppa/mainline/v3.6-rc3-quantal/linux-image-3.6.0-030600rc3-generic_3.6.0-030600rc3.201208221735_amd64.deb http://kernel.ubuntu.com/~kernel-ppa/mainline/v3.6-rc3-quantal/linux-image-extra-3.6.0-030600rc3-generic_3.6.0-030600rc3.201208221735_amd64.deb Step 2: sudo dpkg -i linux*.deb Step 3: reboot which shows that i have Ubuntu 12.04 with latest $ uname -a Linux sun-Alienware-X51 3.6.0-030600rc3-generic #201208221735 SMP Wed Aug 22 21:36:32 UTC 2012 x86_64 x86_64 x86_64 GNU/Linux But still same problem remain.

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  • Solutions for cheaply replacing poorly-supported onboard ATI card with discreet graphics on desktop machine?

    - by echo-flow
    I have put Ubuntu on my mum's desktop computer. Unfortunately, the open source radeon driver does not work well with the onboard ATI graphics, and ATI's proprietary driver no longer supports the hardware at all. In order to use the ATI proprietary driver with this hardware, it is necessary to use an older version of Xorg, which is now only available in versions of Ubuntu older than 8.10. Unfortunately, the open source radeon driver seems to be causing X to lock up intermittently when my mum uses Audacity. I'm willing to accept that some hardware is not well-supported on Ubuntu, and so, because this is a desktop computer with a couple of free PCI slots, I think a better solution might simply be to plug in a new graphics card that might have better driver support, and to disable the onboard ATI card in the BIOS. The requirements for this card are that it be inexpensive and have robust (preferably open source) driver support in Ubuntu 10.04. Heavy-duty graphics processing power is not a requirement. A second-hand card on Ebay would also be fine. Can anyone make some recommendations?

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  • graphics cards with no HDMI output

    - by Noam Gal
    I am currently looking at Gainward GTX260 896MB GS GLH, but I've seen it also on the x275 version - the card doesn't have an HDMI output, only two dvi and one tv out (s-video?). They claim they support HDMI using a dvi-HDMI converter. Will I get a true high definition quality on my TV (assuming it supports it) like that? Or is it not as good, and I should stick to cards that have an HDMI output (ATI), or pay way too much for x295? What about connecting the audio? The x260 comes with an internal spdif cable - does that mean I can connect my soundcard to my graphics card, and have the audio come out through the dvi, and into the HDMI cable? Or am I mixing it all up here, and I have to somehow connect the sound to the TV using a seperate cable (Hoping it has a seperate audio-in for the HDMI channel)?

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