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  • Long numbers. Division.

    - by user577395
    Hello, world! I have a problem. Today I tried to create a code, which finds Catalan number. But in my program can be long numbers. I found numerator and denominator. But i can't div long numbers! Also, only standard libraries was must use in this program. Help me please. This is my code #include <vector> #include <iostream> using namespace std; int main(int argc, char *argv[]) { const int base = 1000*1000*1000; vector <int> a, b; int n, carry = 0; cin>>n; a.push_back(n); for (int ii=n+2; ii!=(2*n)+1;++ii) { carry = 0; for (size_t i=0; i<a.size() || carry; ++i) { if (i == a.size()) a.push_back (0); long long cur = carry + a[i] * 1ll * ii; a[i] = int (cur % base); carry = int (cur / base); } } while (a.size() > 1 && a.back() == 0) a.pop_back(); b.push_back(n); for (int ii=1; ii!=n+1;++ii) { carry = 0; for (size_t i=0; i<b.size() || carry; ++i) { if (i == b.size()) b.push_back (0); long long cur = carry + b[i] * 1ll * ii; b[i] = int (cur % base); carry = int (cur / base); } } while (b.size() > 1 && b.back() == 0) b.pop_back(); cout<<(a.empty() ? 0 : a.back()); for (int i=(int)a.size()-2; i>=0; --i) cout<<(a[i]); cout<<" "; cout<<(b.empty() ? 0 : b.back()); for (int i=(int)b.size()-2; i>=0; --i) cout<<(b[i]); //system("PAUSE"); cout<<endl; return 0; } P.S. Sorry for my bad english =)

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  • Why does SendMailMAPI rename file attachments to shorter ones?

    - by Tom
    I use the following emailing function with Eudora. For some reason the attachment file name is renamed to be something else. How can I make sure the attachment file name remains intact? function SendMailMAPI(const Subject, Body, FileName, SenderName, SenderEMail, RecepientName, RecepientEMail: String) : Integer; var message: TMapiMessage; lpSender, lpRecepient: TMapiRecipDesc; FileAttach: TMapiFileDesc; SM: TFNMapiSendMail; MAPIModule: HModule; begin FillChar(message, SizeOf(message), 0); with message do begin if (Subject<>'') then begin lpszSubject := PChar(Subject) end; if (Body<>'') then begin lpszNoteText := PChar(Body) end; if (SenderEMail<>'') then begin lpSender.ulRecipClass := MAPI_ORIG; if (SenderName='') then begin lpSender.lpszName := PChar(SenderEMail) end else begin lpSender.lpszName := PChar(SenderName) end; lpSender.lpszAddress := PChar('SMTP:'+SenderEMail); lpSender.ulReserved := 0; lpSender.ulEIDSize := 0; lpSender.lpEntryID := nil; lpOriginator := @lpSender; end; if (RecepientEMail<>'') then begin lpRecepient.ulRecipClass := MAPI_TO; if (RecepientName='') then begin lpRecepient.lpszName := PChar(RecepientEMail) end else begin lpRecepient.lpszName := PChar(RecepientName) end; lpRecepient.lpszAddress := PChar('SMTP:'+RecepientEMail); lpRecepient.ulReserved := 0; lpRecepient.ulEIDSize := 0; lpRecepient.lpEntryID := nil; nRecipCount := 1; lpRecips := @lpRecepient; end else begin lpRecips := nil end; if (FileName='') then begin nFileCount := 0; lpFiles := nil; end else begin FillChar(FileAttach, SizeOf(FileAttach), 0); FileAttach.nPosition := Cardinal($FFFFFFFF); FileAttach.lpszPathName := PChar(FileName); nFileCount := 1; lpFiles := @FileAttach; end; end; MAPIModule := LoadLibrary(PChar(MAPIDLL)); if MAPIModule=0 then begin Result := -1 end else begin try @SM := GetProcAddress(MAPIModule, 'MAPISendMail'); if @SM<>nil then begin Result := SM(0, Application.Handle, message, MAPI_DIALOG or MAPI_LOGON_UI, 0); end else begin Result := 1 end; finally FreeLibrary(MAPIModule); end; end; if Result<>0 then begin MessageDlg('Error sending mail ('+IntToStr(Result)+').', mtError, [mbOk], 0) end;

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  • Getting level values from PCM raw data using Core Audio

    - by John
    I am trying to extract level data from a PCM audio file using core audio. I have gotten as far as (I believe) getting the raw data into a byte array (UInt8) but it is 16 bit PCM data and I am having trouble reading the data out. The input is from the iPhone microphone, which I have set as: [recordSetting setValue:[NSNumber numberWithInt:kAudioFormatLinearPCM] forKey:AVFormatIDKey]; [recordSetting setValue:[NSNumber numberWithFloat:44100.0] forKey:AVSampleRateKey]; [recordSetting setValue:[NSNumber numberWithInt:1] forKey:AVNumberOfChannelsKey]; [recordSetting setValue:[NSNumber numberWithInt:16] forKey:AVLinearPCMBitDepthKey]; [recordSetting setValue:[NSNumber numberWithBool:NO] forKey:AVLinearPCMIsBigEndianKey]; [recordSetting setValue:[NSNumber numberWithBool:NO] forKey:AVLinearPCMIsFloatKey]; which is obviously 16 bits. I am then trying to just print out a few values to see if they look reasonable for debug purposes below, and they do not look reasonable (many 0's). ExtAudioFileRef inputFile = NULL; ExtAudioFileOpenURL(track.location, &inputFile); AudioStreamBasicDescription inputFileFormat; UInt32 dataSize = (UInt32)sizeof(inputFileFormat); ExtAudioFileGetProperty(inputFile, kExtAudioFileProperty_FileDataFormat, &dataSize, &inputFileFormat); UInt8 *buffer = malloc(BUFFER_SIZE); AudioBufferList bufferList; bufferList.mNumberBuffers = 1; bufferList.mBuffers[0].mNumberChannels = 1; bufferList.mBuffers[0].mData = buffer; //pointer to buffer of audio data bufferList.mBuffers[0].mDataByteSize = BUFFER_SIZE; //number of bytes in the buffer while(true) { UInt32 frameCount = (bufferList.mBuffers[0].mDataByteSize / inputFileFormat.mBytesPerFrame); // Read a chunk of input OSStatus status = ExtAudioFileRead(inputFile, &frameCount, &bufferList); // If no frames were returned, conversion is finished if(0 == frameCount) break; NSLog(@"---"); int16_t *bufferl = &buffer; for(int i=0;i<100;i++){ //const int16_t *bufferl = bufferl[i]; NSLog(@"%d",bufferl[i]); } } Not sure what I am doing wrong, I think it has to do with reading the byte array. Sorry for the long code post...

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  • What's the fastest lookup algorithm for a key, pair data structure (i.e, a map)?

    - by truncheon
    In the following example a std::map structure is filled with 26 values from A - Z (for key) and 0 – 26 for value. The time taken (on my system) to lookup the last entry (10000000 times) is roughly 250 ms for the vector, and 125 ms for the map. (I compiled using release mode, with O3 option turned on for g++ 4.4) But if for some odd reason I wanted better performance than the std::map, what data structures and functions would I need to consider using? I apologize if the answer seems obvious to you, but I haven't had much experience in the performance critical aspects of C++ programming. #include <ctime> #include <map> #include <vector> #include <iostream> struct mystruct { char key; int value; mystruct(char k = 0, int v = 0) : key(k), value(v) { } }; int find(const std::vector<mystruct>& ref, char key) { for (std::vector<mystruct>::const_iterator i = ref.begin(); i != ref.end(); ++i) if (i->key == key) return i->value; return -1; } int main() { std::map<char, int> mymap; std::vector<mystruct> myvec; for (int i = 'a'; i < 'a' + 26; ++i) { mymap[i] = i - 'a'; myvec.push_back(mystruct(i, i - 'a')); } int pre = clock(); for (int i = 0; i < 10000000; ++i) { find(myvec, 'z'); } std::cout << "linear scan: milli " << clock() - pre << "\n"; pre = clock(); for (int i = 0; i < 10000000; ++i) { mymap['z']; } std::cout << "map scan: milli " << clock() - pre << "\n"; return 0; }

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  • if non zero elements in same column count only once

    - by George
    I want to check the elements above the main diagonal and if I found non zero values , count one. If the non zero values are found in the same column ,then count just one ,not the number of the non zero values. For example , it should be count = 2 and not 3 in this example because 12 and 6 are in the same column. A= 1 11 12 4 5 6 0 7 0 #include <stdio.h> #include <stdlib.h> #include <math.h> int main( int argc, const char* argv[] ){ int Rows = 3 , Cols = 3; float *A = (float *) malloc ( Rows * Cols * sizeof (float) ); A[0] = 1.0; A[1] = 11.0; A[2] = 12.0; A[3] = 4.0; A[4] = 5.0; A[5] = 6.0; A[6] = 0.0; A[7] = 7.0; A[8] = 0.0; // print input matrix printf("\n Input matrix \n\n"); for ( int i = 0; i < Rows; i++ ) for ( int j = 0; j < Cols; j++ ) { printf("%f\t",A[ i * Cols + j ]); if( j == Cols-1 ) printf("\n"); } printf("\n"); int count = 0; for ( int j = 0 ; j < Cols; j++ ) { for ( int i = ( Rows - 1 ); i >= 0; i-- ) { // check the diagonal elements above the main diagonal if ( j > i ) { if ( ( A[ i * Cols + j ] != 0 ) ) { printf("\n Above nonzero Elmts = %f\n",( A[i * Cols + j] ) ); count++; } } } } printf("\ncount = %d\n",count ); return 0; }

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  • Converting OpenGL coordinates to lower UIView (and UIImagePickerController)

    - by John Qualis
    I am new to OpenGL on the iPhone. I am developing an iPhone app similar to a barcode reader but with an extra OpenGL layer. The bottommost layer is UIImagePickerController, then I use UIView on top and draw a rectangle at certain coordinates on the iPhone screen. So far everything is OK. Then I am trying to draw an OpenGL 3-D model in that rectangle. I am able to load a 3-D model in the iPhone based on this code here - http://iphonedevelopment.blogspot.com/2008/12/start-of-wavefront-obj-file-loader.html I am not able to transform the coordinates of the rectangle into OpenGL coordinates. Appreciate any help. Do I need to use a matrix to translate the currentPosition of the 3-D model so it is drawn within myRect? The code is given below. -(void)setupView:(GLView*)view { const GLfloat zNear = 0.01, zFar = 1000.0, fieldOfView = 45.0; GLfloat size; glEnable(GL_DEPTH_TEST); glMatrixMode(GL_PROJECTION); size = zNear * tanf(DEGREES_TO_RADIANS(fieldOfView) / 2.0); CGRect rect = view.bounds; glFrustumf(-size, size, -size / (rect.size.width / rect.size.height), size / (rect.size.width / rect.size.height), zNear, zFar); glViewport(0, 0, rect.size.width, rect.size.height); glMatrixMode(GL_MODELVIEW); glLoadIdentity(); glClearColor(0.0f, 0.0f, 0.0f, 0.0f); NSString *path = [[NSBundle mainBundle] pathForResource:@"plane" ofType:@"obj"]; OpenGLWaveFrontObject *theObject = [[OpenGLWaveFrontObject alloc] initWithPath:path]; Vertex3D position; position.z = -8.0; position.y = 3.0; position.x = 2.0; theObject.currentPosition = position; self.plane = theObject; [theObject release]; } - (void)drawView:(GLView*)view; { static GLfloat rotation = 0.0; glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); glLoadIdentity(); glColor4f(0.0, 0.5, 1.0, 1.0); // the coordinates of the rectangle are // myRect.x, myRect.y, myRect.width, myRect.height // Do I need to use a matrix to translate the currentPosition of the // 3-D model so it is drawn within myRect? //glOrthof(-160.0f, 160.0f, -240.0f, 240.0f, -1.0f, 1.0f); [plane drawSelf]; }

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  • [C#] How to do a search from a list with non-prefix keywords

    - by aNui
    First of all, sorry if my english or my post got any mistakes. I am programming a program to search the name from the list and I need to find them if the keyword is not in front of the names (that's what I mean non-prefix) e.g. if I my list is the music instruments and I type "guit" to the search textbox. It should find the names "Guitar, Guitarrón, Acoustic Guitar, Bass Guitar, ..." or something like this Longdo Dictionary's search suggestion. here is my simple and stupid algorithm (that's all I can do) const int SEARCHROWLIMIT = 30; private string[] DoSearch(string Input, string[] ListToSearch) { List<string> FoundNames = new List<string>(); int max = 0; bool over = false; for (int k = 0; !over; k++) { foreach (string item in ListToSearch) { max = (max > item.Length) ? max : item.Length; if (k > item.Length) continue; if (k >= max) { over = true; break; } if (!Input.Equals("Search") && item.Substring(k, item.Length - k).StartsWith(Input, StringComparison.OrdinalIgnoreCase)) { bool exist = false; int i = 0; while (!exist && i < FoundNames.Count) { if (item.Equals(FoundNames[i])) { exist = true; break; } i++; } if (!exist && FoundNames.Count < SEARCHROWLIMIT) FoundNames.Add(item); else if (FoundNames.Count >= SEARCHROWLIMIT) over = true; } } } return FoundNames.ToArray(); } I think this algorithm is too slow for a large number of names and after several trial-and-error, I decided to add SEARCHROWLIMIT to breaks the operation And I also think there're some readymade methods that can do that. And another problem is I need to search music instruments by a category like strings, percussions, ... and by the country of origins. So I need to search them with filter by type and country. please help me. P.S. Me and my friends are just student from Thailand and developing the project to compete in Microsoft Imagine Cup 2010 and please become fan on our facebook page [KRATIB][3]. And we're so sorry we don't have much information in English but you can talk to us in English.

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  • sqlite 3 opening issue

    - by anonymous
    I'm getting my data ,with several similar methods, from sqlite3 file like in following code: -(NSMutableArray *) getCountersByID:(NSString *) championID{ NSMutableArray *arrayOfCounters; arrayOfCounters = [[NSMutableArray alloc] init]; @try { NSFileManager *fileManager = [NSFileManager defaultManager]; NSString *databasePath = [[[NSBundle mainBundle] resourcePath ]stringByAppendingPathComponent:@"DatabaseCounters.sqlite"]; BOOL success = [fileManager fileExistsAtPath:databasePath]; if (!success) { NSLog(@"cannot connect to Database! at filepath %@",databasePath); } else{ NSLog (@"SUCCESS getCountersByID!!"); } if(sqlite3_open([databasePath UTF8String], &database) == SQLITE_OK){ NSString *tempString = [NSString stringWithFormat:@"SELECT COUNTER_ID FROM COUNTERS WHERE CHAMPION_ID = %@",championID]; const char *sql = [tempString cStringUsingEncoding:NSASCIIStringEncoding]; sqlite3_stmt *sqlStatement; int ret = sqlite3_prepare(database, sql, -1, &sqlStatement, NULL); if (ret != SQLITE_OK) { NSLog(@"Error calling sqlite3_prepare: %d", ret); } if(sqlite3_prepare_v2(database, sql, -1, &sqlStatement, NULL) == SQLITE_OK){ while (sqlite3_step(sqlStatement)==SQLITE_ROW) { counterList *CounterList = [[counterList alloc]init]; CounterList.counterID = [NSString stringWithUTF8String:(char *) sqlite3_column_text(sqlStatement,0)]; [arrayOfCounters addObject:CounterList]; } } else{ NSLog(@"problem with database prepare"); } sqlite3_finalize(sqlStatement); } else{ NSLog(@"problem with database openning %s",sqlite3_errmsg(database)); } } @catch (NSException *exception){ NSLog(@"An exception occured: %@", [exception reason]); } @finally{ sqlite3_close(database); return arrayOfCounters; } //end } then i'm getting access to data with this and other similar lines of code: myCounterList *MyCounterList = [[myCounterList alloc] init]; countersTempArray = [MyCounterList getCountersByID:"2"]; [countersArray addObject:[NSString stringWithFormat:@"%@",(((counterList *) [countersTempArray objectAtIndex:i]).counterID)]]; I'm getting a lot of data like image name and showing combination of them that depends on users input with such code: UIImage *tempImage = [UIImage imageNamed:[NSString stringWithFormat:@"%@_0.jpg",[countersArray objectAtIndex:0]]]; [championSelection setBackgroundImage:tempImage forState:UIControlStateNormal]; My problem: When i'm run my app for some time and get a lot of data it throws error: " problem with database openning unable to open database file - error = 24 (Too many open files)" My guess is that i'm opening my database every time when getCountersByID is called but not closing it. My question: Am i using right approach to open and close database that i use? Similar questions that have not helped me to solve this problem: unable to open database Sqlite Opening Error : Unable to open database UPDATE: I made assumption that error is showing up because i use this lines of code too much: NSFileManager *fileManager = [NSFileManager defaultManager]; NSString *databasePath = [[[NSBundle mainBundle] resourcePath ]stringByAppendingPathComponent:@"DatabaseCounters.sqlite"]; BOOL success = [fileManager fileExistsAtPath:databasePath]; and ending up with error 24. So i made them global but sqlite3_errmsg shows same err 24, but app runs much faster now I'll try to debug my app, see what happens

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  • Detect if class has overloaded function fails on Comeau compiler

    - by Frank
    Hi Everyone, I'm trying to use SFINAE to detect if a class has an overloaded member function that takes a certain type. The code I have seems to work correctly in Visual Studio and GCC, but does not compile using the Comeau online compiler. Here is the code I'm using: #include <stdio.h> //Comeau doesnt' have boost, so define our own enable_if_c template<bool value> struct enable_if_c { typedef void type; }; template<> struct enable_if_c< false > {}; //Class that has the overloaded member function class TestClass { public: void Func(float value) { printf( "%f\n", value ); } void Func(int value) { printf( "%i\n", value ); } }; //Struct to detect if TestClass has an overloaded member function for type T template<typename T> struct HasFunc { template<typename U, void (TestClass::*)( U )> struct SFINAE {}; template<typename U> static char Test(SFINAE<U, &TestClass::Func>*); template<typename U> static int Test(...); static const bool Has = sizeof(Test<T>(0)) == sizeof(char); }; //Use enable_if_c to only allow the function call if TestClass has a valid overload for T template<typename T> typename enable_if_c<HasFunc<T>::Has>::type CallFunc(TestClass &test, T value) { test.Func( value ); } int main() { float value1 = 0.0f; int value2 = 0; TestClass testClass; CallFunc( testClass, value1 ); //Should call TestClass::Func( float ) CallFunc( testClass, value2 ); //Should call TestClass::Func( int ) } The error message is: no instance of function template "CallFunc" matches the argument list. It seems that HasFunc::Has is false for int and float when it should be true. Is this a bug in the Comeau compiler? Am I doing something that's not standard? And if so, what do I need to do to fix it?

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  • How to remove .zip file in c on windows? (error: Directory not empty)

    - by ExtremeBlue
    include include include include "win32-dirent.h" include include include define MAXFILEPATH 1024 bool IsDirectory(char* path) { WIN32_FIND_DATA w32fd; HANDLE hFindFile; hFindFile = FindFirstFile((PTCHAR)path, &w32fd); if(hFindFile == INVALID_HANDLE_VALUE) { return false; } return w32fd.dwFileAttributes & (FILE_ATTRIBUTE_DIRECTORY); } int RD(const char* folderName) { DIR *dir; struct dirent *ent; dir = opendir(folderName); if(dir != NULL) { while((ent = readdir(dir)) != NULL) { if(strcmp(ent->d_name , ".") == 0 || strcmp(ent->d_name, "..") == 0) { continue; } char fileName[MAXFILEPATH]; sprintf(fileName,"%s%c%s", folderName, '\\', ent->d_name); if(IsDirectory(fileName)) { RD(fileName); } else { unlink(fileName); } } closedir(dir); //chmod(folderName, S_IWRITE | S_IREAD); if(_rmdir(folderName) != 0)perror(folderName); } else { printf("%s <%s>\n","Could Not Open Directory.", folderName); return -1; } return 0; } int main(int argc, char* argv[]) { if(argc < 2) { printf("usage: ./a.out \n"); return 1; } //RD(argv[1]); //_mkdir("12"); //_mkdir("12\\34"); //_rmdir("12\\34"); //_rmdir("12"); char buf[0xff]; sprintf(buf, "unzip -x -q -d 1234 1234.zip"); system(buf); RD("1234"); //unlink("D:\\dev\\c\\project\\removeFolder\\Debug\\1234\\56\\5.txt"); //unlink("D:\\dev\\c\\project\\removeFolder\\Debug\\1234\\56\\6.txt"); //unlink("D:\\dev\\c\\project\\removeFolder\\Debug\\1234\\1_23.zip"); //unlink("D:\\dev\\c\\project\\removeFolder\\Debug\\1234\\4.txt"); //_rmdir("D:\\dev\\c\\project\\removeFolder\\Debug\\1234\\56"); //_rmdir("D:\\dev\\c\\project\\removeFolder\\Debug\\1234"); return 0; } Archive: 1234.zip inflating: 1234/4.txt inflating: 1234/56/5.txt inflating: 1234/56/6.txt inflating: 1234/1_23.zip

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  • C: copying some structs causes strange behavior

    - by Jenny B
    I have an annoying bug in the line rq->tickets[rq->usedContracts] = toAdd; if i do: rq->tickets[0] = toAdd the program crashes if i do rq->tickets[1] = toAdd; it works valgrind says ==19501== Use of uninitialised value of size 8 and ==19501== Invalid write of size 8 for this very line. What is wrong? struct TS_element { int travels; int originalTravels; int cost; char** dates; int moneyLeft; } TicketSet; struct RQ_element { int usedContracts; struct TS_element* tickets; } RabQav; TicketSetStatus tsCreate(TicketSet* t, int n, int c) { if (n <= 0) return TS_ILLEGAL_PARAMETER; TicketSet* myTicketSet = (TicketSet*) malloc(sizeof(TicketSet)); if (myTicketSet == NULL) { return TS_CANNOT_CREATE; } myTicketSet->usedTravels = 0; myTicketSet->originalTravels = n; myTicketSet->cost = c; myTicketSet->moneyLeft = n * c; char** dates = malloc(sizeof(char**)* (n)); //todo maybe c99 allows dynamic arrays? for (int i = 0; i < n; i++) { dates[i] = malloc(sizeof(char)*GOOD_LENGTH+1); if (dates[i] == NULL) { free(dates); free(t); return TS_CANNOT_CREATE; } } myTicketSet->dates = dates; *t = *myTicketSet; return TS_SUCCESS; } static void copyTicketSets(TicketSet* dest, const TicketSet* source) { dest->usedTravels = source->usedTravels; dest->originalTravels = source->originalTravels; dest->cost = source->cost; dest->moneyLeft = source->moneyLeft; for (int i = 0; i < source->originalTravels; i++) { if (NULL != source->dates[i]) { free(dest->dates[i]); dest->dates[i] = malloc(sizeof(char) * GOOD_LENGTH + 1); if (dest->dates[i] == NULL) { free(dest->dates); //todo free dates 0...i-1 free(dest); return; } strcpy(dest->dates[i], source->dates[i]); } } } RabQavStatus rqLoadTS(RabQav* rq, TicketSet t, DateTime dt) { TicketSet toAdd; TicketSetStatus res = tsCreate(&toAdd, t.originalTravels, t.cost); if (res != TS_SUCCESS) { return RQ_FAIL; } copyTicketSets(&toAdd, &t); rq->tickets[rq->usedContracts] = toAdd; rq->usedContracts++; return RQ_SUCCESS; }

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  • pointer to preallocated memory as an input parameter and have the function fill it

    - by djones2010
    test code: void modify_it(char * mystuff) { char test[7] = "123456"; //last element is null i presume for c style strings here. //static char test[] = "123123"; //when i do this i thought i should be able to gain access to this bit of memory when the function is destroyed but that does not seem to be the case. //char * test = new char[7]; //this is also creating memory on stack and not the heap i reckon and gets destroyed once the function is done with. strcpy_s(mystuff,7,test); //this does the job as long as memory for mystuff has been allocated outside the function. mystuff = test; //this does not work. I know with c style strings you can't just do string assignments they have to be actually copied. in this case I was using this in conjunction with static char test thinking by having it as static the memory would not get destroyed and i can then simply point mystuff to test and be done with it. i would later have address the memory cleanup in the main function. but anyway this never worked. } int main(void) { char * mystuff = new char [7]; //allocate memory on heap where the pointer will point cool(mystuff); std::string test_case(mystuff); std::cout<<test_case.c_str(); //this is the only way i know how to use cout by making it into a string c++ string. delete [] mystuff; return 0; } in the case, of a static array in the function why would it not work. in the case, when i allocated memory using new in the function does it get created on the stack or heap? in the case, i have string which needs to be copied into a char * form. everything i see usually requires const char* instead of just char*. I know i could use reference to take care of this easy. Or char ** to send in the pointer and do it that way. But i just wanted to know if I could do it with just char *. Anyway your thoughts and comments plus any examples would be very helpful.

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  • Sending a file from memory (rather than disk) over HTTP using libcurl

    - by cinek1lol
    Hi! I would like to send pictures via a program written in C + +. - OK WinExec("C:\\curl\\curl.exe -H Expect: -F \"fileupload=@C:\\curl\\ok.jpg\" -F \"xml=yes\" -# \"http://www.imageshack.us/index.php\" -o data.txt -A \"Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.8.1.1) Gecko/20061204 Firefox/2.0.0.1\" -e \"http://www.imageshack.us\"", NULL); It works, but I would like to send the pictures from pre-loaded carrier to a variable char (you know what I mean? First off, I load the pictures into a variable and then send the variable), cause now I have to specify the path of the picture on a disk. I wanted to write this program in c++ by using the curl library, not through exe. extension. I have also found such a program (which has been modified by me a bit) #include <stdio.h> #include <string.h> #include <iostream> #include <curl/curl.h> #include <curl/types.h> #include <curl/easy.h> int main(int argc, char *argv[]) { CURL *curl; CURLcode res; struct curl_httppost *formpost=NULL; struct curl_httppost *lastptr=NULL; struct curl_slist *headerlist=NULL; static const char buf[] = "Expect:"; curl_global_init(CURL_GLOBAL_ALL); /* Fill in the file upload field */ curl_formadd(&formpost, &lastptr, CURLFORM_COPYNAME, "send", CURLFORM_FILE, "nowy.jpg", CURLFORM_END); curl_formadd(&formpost, &lastptr, CURLFORM_COPYNAME, "nowy.jpg", CURLFORM_COPYCONTENTS, "nowy.jpg", CURLFORM_END); curl_formadd(&formpost, &lastptr, CURLFORM_COPYNAME, "submit", CURLFORM_COPYCONTENTS, "send", CURLFORM_END); curl = curl_easy_init(); headerlist = curl_slist_append(headerlist, buf); if(curl) { curl_easy_setopt(curl, CURLOPT_URL, "http://www.imageshack.us/index.php"); if ( (argc == 2) && (!strcmp(argv[1], "xml=yes")) ) curl_easy_setopt(curl, CURLOPT_HTTPHEADER, headerlist); curl_easy_setopt(curl, CURLOPT_HTTPPOST, formpost); res = curl_easy_perform(curl); curl_easy_cleanup(curl); curl_formfree(formpost); curl_slist_free_all (headerlist); } system("pause"); return 0; }

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  • how to create multiple tcp connections between server and client

    - by lowcosthighperformance
    I am new in Unix/Linux networking programming, so I have written server-client program in below.In this code there is one socket between client and server, client requests to server, then server responses from 1 to 100 numbers to client. So my question is how can we do this process with 3 socket( tcp connection) without using thread? ( e.g. First socket runs then second runs then third runs then first again .. ) Do you have any suggestion? Thank you client.c int main() { int sock; struct sockaddr_in sa; int ret; char buf[1024]; int x; sock = socket (AF_INET, SOCK_STREAM, 0); bzero (&sa, sizeof(sa)); sa.sin_family = AF_INET; sa.sin_port = htons(SERVER_PORT); inet_pton (AF_INET, SERVER_IP, &sa.sin_addr); ret = connect (sock, (const struct sockaddr *) &sa,sizeof (sa)); if (ret != 0) { printf ("connect failed\n"); exit (0); } x = 0; while (x != -1) { read (sock, buf , sizeof(int)); x = ntohl(*((int *)buf)); if (x != -1) printf ("int rcvd = %d\n", x); } close (sock); exit (0); } server.c int main() { int list_sock; int conn_sock; struct sockaddr_in sa, ca; socklen_t ca_len; char buf[1024]; int i; char ipaddrstr[IPSTRLEN]; list_sock = socket (AF_INET, SOCK_STREAM, 0); bzero (&sa, sizeof(sa)); sa.sin_family = AF_INET; sa.sin_addr.s_addr = htonl(INADDR_ANY); sa.sin_port = htons(SERVER_PORT); bind (list_sock,(struct sockaddr *) &sa,sizeof(sa)); listen (list_sock, 5); while (1){ bzero (&ca, sizeof(ca)); ca_len = sizeof(ca); // important to initialize conn_sock = accept (list_sock,(struct sockaddr *) &ca,&ca_len); printf ("connection from: ip=%s port=%d \n",inet_ntop(AF_INET, &(ca.sin_addr), ipaddrstr, IPSTRLEN),ntohs(ca.sin_port)); for (i=0; i<100; ++i){ *((int *)buf) = htonl(i+20); // we using converting to network byte order write (conn_sock, buf, sizeof(int)); } * ((int *)buf) = htonl(-1); write (conn_sock, buf, sizeof(int)); close (conn_sock); printf ("server closed connection to client\n"); } }

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  • why my test performance class gives me inconsistent results even after proper warm-up?

    - by colinfang
    i made a class which helps me measure time for any methods in Ticks. Basically, it runs testing method 100x, and force GC, then it records time taken for another 100x method runs. x64 release ctrl+f5 VS2012/VS2010 the results are following: 2,914 2,909 2,913 2,909 2,908 2,907 2,909 2,998 2,976 2,855 2,446 2,415 2,435 2,401 2,402 2,402 2,399 2,401 2,401 2,400 2,399 2,400 2,404 2,402 2,401 2,399 2,400 2,402 2,404 2,403 2,401 2,403 2,401 2,400 2,399 2,414 2,405 2,401 2,407 2,399 2,401 2,402 2,401 2,404 2,401 2,404 2,405 2,368 1,577 1,579 1,626 1,578 1,576 1,578 1,577 1,577 1,576 1,578 1,576 1,578 1,577 1,578 1,576 1,578 1,577 1,579 1,585 1,576 1,579 1,577 1,579 1,578 1,579 1,577 1,578 1,577 1,578 1,576 1,578 1,577 1,578 1,599 1,579 1,578 1,582 1,576 1,578 1,576 1,579 1,577 1,578 1,577 1,591 1,577 1,578 1,578 1,576 1,578 1,576 1,578 As you can see there are 3 phases, first is ~2,900, second is ~2,400, then ~1,550 What might be the reason to cause it? the test performance class code follows: public static void RunTests(Func<long> myTest) { const int numTrials = 100; Stopwatch sw = new Stopwatch(); double[] sample = new double[numTrials]; Console.WriteLine("Checksum is {0:N0}", myTest()); sw.Start(); myTest(); sw.Stop(); Console.WriteLine("Estimated time per test is {0:N0} ticks\n", sw.ElapsedTicks); for (int i = 0; i < numTrials; i++) { myTest(); } GC.Collect(); string testName = myTest.Method.Name; Console.WriteLine("----> Starting benchmark {0}\n", myTest.Method.Name); for (int i = 0; i < numTrials; i++) { sw.Restart(); myTest(); sw.Stop(); sample[i] = sw.ElapsedTicks; } double testResult = DataSetAnalysis.Report(sample); for (int j = 0; j < numTrials; j = j + 5) Console.WriteLine("{0,8:N0} {1,8:N0} {2,8:N0} {3,8:N0} {4,8:N0}", sample[j], sample[j + 1], sample[j + 2], sample[j + 3], sample[j + 4]); Console.WriteLine("\n----> End of benchmark"); }

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  • Split a binary file into chunks c++

    - by L4nce0
    I've been bashing my head against trying to first divide up a file into chunks, for the purpose of sending over sockets. I can read / write a file easily without splitting it into chunks. The code below runs, works, kinda. It will write a textfile and has a garbage character. Which if this was just for txt, no problem. Jpegs aren't working with said garbage. Been at it for a few days, so I've done my research, and it's time to get some help. I do want to stick strictly to binary readers, as this need to handle any file. I've seen a lot of slick examples out there. (none of them worked for me with jpgs) Mostly something along the lines of while(file)... I subscribe to the, if you know the size, use a for-loop, not a while-loop camp. Thank you for the help!! vector<char*> readFile(const char* fn){ vector<char*> v; ifstream::pos_type size; char * memblock; ifstream file; file.open(fn,ios::in|ios::binary|ios::ate); if (file.is_open()) { size = fileS(fn); file.seekg (0, ios::beg); int bs = size/3; // arbitrary. Actual program will use the socket send size int ws = 0; int i = 0; for(i = 0; i < size; i+=bs){ if(i+bs > size) ws = size%bs; else ws = bs; memblock = new char [ws]; file.read (memblock, ws); v.push_back(memblock); } } else{ exit(-4); } return v; } int main(int argc, char **argv) { vector<char*> v = readFile("foo.txt"); ofstream myFile ("bar.txt", ios::out | ios::binary); for(vector<char*>::iterator it = v.begin(); it!=v.end(); ++it ){ myFile.write(*it,strlen(*it)); } }

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  • curl problems in c++ class

    - by Danilo
    I read a few articles on c++ / curl here on stackoverflow and assembled the following. The main goal is to handle the whole request in an instance of a class -- and maybe later in a secondary thread. My problem is: "content_" seems to stay empty though its the same addr and HttpFetch.h: class HttpFetch { private: CURL *curl; static size_t handle(char * data, size_t size, size_t nmemb, void * p); size_t handle_impl(char * data, size_t size, size_t nmemb); public: std::string content_; static std::string url_; HttpFetch(std::string url); void start(); std::string data(); }; HttpFetch.cpp: HttpFetch::HttpFetch(std::string url) { curl_global_init(CURL_GLOBAL_ALL); //pretty obvious curl = curl_easy_init(); content_.append("Test"); std::cout << &content_ << "\n"; curl_easy_setopt(curl, CURLOPT_URL, &url); curl_easy_setopt(curl, CURLOPT_WRITEDATA, &content_); curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, &HttpFetch::handle); //curl_easy_setopt(curl, CURLOPT_VERBOSE, 1L); //tell curl to output its progress curl_easy_setopt(curl, CURLOPT_FOLLOWLOCATION, 1L); //std::cout << &content_ << "\n"; } void HttpFetch::start() { curl_easy_perform(curl); curl_easy_cleanup(curl); } size_t HttpFetch::handle(char * data, size_t size, size_t nmemb, void * p) { std::string *stuff = reinterpret_cast<std::string*>(p); stuff->append(data, size * nmemb); std::cout << stuff << "\n"; // has content from data in it! return size * nmemb; } main.cpp: #include "HttpFetch.h" int main(int argc, const char * argv[]) { HttpFetch call = *new HttpFetch("http://www.example.com"); call.start(); ::std::cout << call.content_ << "\n" } Thanks in advance

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  • Segfault when iterating over a map<string, string> and drawing its contents using SDL_TTF

    - by Michael Stahre
    I'm not entirely sure this question belongs on gamedev.stackexchange, but I'm technically working on a game and working with SDL, so it might not be entirely offtopic. I've written a class called DebugText. The point of the class is to have a nice way of printing values of variables to the game screen. The idea is to call SetDebugText() with the variables in question every time they change or, as is currently the case, every time the game's Update() is called. The issue is that when iterating over the map that contains my variables and their latest updated values, I get segfaults. See the comments in DrawDebugText() below, it specifies where the error happens. I've tried splitting the calls to it-first and it-second into separate lines and found that the problem doesn't always happen when calling it-first. It alters between it-first and it-second. I can't find a pattern. It doesn't fail on every call to DrawDebugText() either. It might fail on the third time DrawDebugText() is called, or it might fail on the fourth. Class header: #ifndef CLIENT_DEBUGTEXT_H #define CLIENT_DEBUGTEXT_H #include <Map> #include <Math.h> #include <sstream> #include <SDL.h> #include <SDL_ttf.h> #include "vector2.h" using std::string; using std::stringstream; using std::map; using std::pair; using game::Vector2; namespace game { class DebugText { private: TTF_Font* debug_text_font; map<string, string>* debug_text_list; public: void SetDebugText(string var, bool value); void SetDebugText(string var, float value); void SetDebugText(string var, int value); void SetDebugText(string var, Vector2 value); void SetDebugText(string var, string value); int DrawDebugText(SDL_Surface*, SDL_Rect*); void InitDebugText(); void Clear(); }; } #endif Class source file: #include "debugtext.h" namespace game { // Copypasta function for handling the toString conversion template <class T> inline string to_string (const T& t) { stringstream ss (stringstream::in | stringstream::out); ss << t; return ss.str(); } // Initializes SDL_TTF and sets its font void DebugText::InitDebugText() { if(TTF_WasInit()) TTF_Quit(); TTF_Init(); debug_text_font = TTF_OpenFont("LiberationSans-Regular.ttf", 16); TTF_SetFontStyle(debug_text_font, TTF_STYLE_NORMAL); } // Iterates over the current debug_text_list and draws every element on the screen. // After drawing with SDL you need to get a rect specifying the area on the screen that was changed and tell SDL that this part of the screen needs to be updated. this is done in the game's Draw() function // This function sets rects_to_update to the new list of rects provided by all of the surfaces and returns the number of rects in the list. These two parameters are used in Draw() when calling on SDL_UpdateRects(), which takes an SDL_Rect* and a list length int DebugText::DrawDebugText(SDL_Surface* screen, SDL_Rect* rects_to_update) { if(debug_text_list == NULL) return 0; if(!TTF_WasInit()) InitDebugText(); rects_to_update = NULL; // Specifying the font color SDL_Color font_color = {0xff, 0x00, 0x00, 0x00}; // r, g, b, unused int row_count = 0; string line; // The iterator variable map<string, string>::iterator it; // Gets the iterator and iterates over it for(it = debug_text_list->begin(); it != debug_text_list->end(); it++) { // Takes the first value (the name of the variable) and the second value (the value of the parameter in string form) //---------THIS LINE GIVES ME SEGFAULTS----- line = it->first + ": " + it->second; //------------------------------------------ // Creates a surface with the text on it that in turn can be rendered to the screen itself later SDL_Surface* debug_surface = TTF_RenderText_Solid(debug_text_font, line.c_str(), font_color); if(debug_surface == NULL) { // A standard check for errors fprintf(stderr, "Error: %s", TTF_GetError()); return NULL; } else { // If SDL_TTF did its job right, then we now set a destination rect row_count++; SDL_Rect dstrect = {5, 5, 0, 0}; // x, y, w, h dstrect.x = 20; dstrect.y = 20*row_count; // Draws the surface with the text on it to the screen int res = SDL_BlitSurface(debug_surface,NULL,screen,&dstrect); if(res != 0) { //Just an error check fprintf(stderr, "Error: %s", SDL_GetError()); return NULL; } // Creates a new rect to specify the area that needs to be updated with SDL_Rect* new_rect_to_update = (SDL_Rect*) malloc(sizeof(SDL_Rect)); new_rect_to_update->h = debug_surface->h; new_rect_to_update->w = debug_surface->w; new_rect_to_update->x = dstrect.x; new_rect_to_update->y = dstrect.y; // Just freeing the surface since it isn't necessary anymore SDL_FreeSurface(debug_surface); // Creates a new list of rects with room for the new rect SDL_Rect* newtemp = (SDL_Rect*) malloc(row_count*sizeof(SDL_Rect)); // Copies the data from the old list of rects to the new one memcpy(newtemp, rects_to_update, (row_count-1)*sizeof(SDL_Rect)); // Adds the new rect to the new list newtemp[row_count-1] = *new_rect_to_update; // Frees the memory used by the old list free(rects_to_update); // And finally redirects the pointer to the old list to the new list rects_to_update = newtemp; newtemp = NULL; } } // When the entire map has been iterated over, return the number of lines that were drawn, ie. the number of rects in the returned rect list return row_count; } // The SetDebugText used by all the SetDebugText overloads // Takes two strings, inserts them into the map as a pair void DebugText::SetDebugText(string var, string value) { if (debug_text_list == NULL) { debug_text_list = new map<string, string>(); } debug_text_list->erase(var); debug_text_list->insert(pair<string, string>(var, value)); } // Writes the bool to a string and calls SetDebugText(string, string) void DebugText::SetDebugText(string var, bool value) { string result; if (value) result = "True"; else result = "False"; SetDebugText(var, result); } // Does the same thing, but uses to_string() to convert the float void DebugText::SetDebugText(string var, float value) { SetDebugText(var, to_string(value)); } // Same as above, but int void DebugText::SetDebugText(string var, int value) { SetDebugText(var, to_string(value)); } // Vector2 is a struct of my own making. It contains the two float vars x and y void DebugText::SetDebugText(string var, Vector2 value) { SetDebugText(var + ".x", to_string(value.x)); SetDebugText(var + ".y", to_string(value.y)); } // Empties the list. I don't actually use this in my code. Shame on me for writing something I don't use. void DebugText::Clear() { if(debug_text_list != NULL) debug_text_list->clear(); } }

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  • Deferred rendering with VSM - Scaling light depth loses moments

    - by user1423893
    I'm calculating my shadow term using a VSM method. This works correctly when using forward rendered lights but fails with deferred lights. // Shadow term (1 = no shadow) float shadow = 1; // [Light Space -> Shadow Map Space] // Transform the surface into light space and project // NB: Could be done in the vertex shader, but doing it here keeps the // "light shader" abstraction and doesn't limit the number of shadowed lights float4x4 LightViewProjection = mul(LightView, LightProjection); float4 surf_tex = mul(position, LightViewProjection); // Re-homogenize // 'w' component is not used in later calculations so no need to homogenize (it will equal '1' if homogenized) surf_tex.xyz /= surf_tex.w; // Rescale viewport to be [0,1] (texture coordinate system) float2 shadow_tex; shadow_tex.x = surf_tex.x * 0.5f + 0.5f; shadow_tex.y = -surf_tex.y * 0.5f + 0.5f; // Half texel offset //shadow_tex += (0.5 / 512); // Scaled distance to light (instead of 'surf_tex.z') float rescaled_dist_to_light = dist_to_light / LightAttenuation.y; //float rescaled_dist_to_light = surf_tex.z; // [Variance Shadow Map Depth Calculation] // No filtering float2 moments = tex2D(ShadowSampler, shadow_tex).xy; // Flip the moments values to bring them back to their original values moments.x = 1.0 - moments.x; moments.y = 1.0 - moments.y; // Compute variance float E_x2 = moments.y; float Ex_2 = moments.x * moments.x; float variance = E_x2 - Ex_2; variance = max(variance, Bias.y); // Surface is fully lit if the current pixel is before the light occluder (lit_factor == 1) // One-tailed inequality valid if float lit_factor = (rescaled_dist_to_light <= moments.x - Bias.x); // Compute probabilistic upper bound (mean distance) float m_d = moments.x - rescaled_dist_to_light; // Chebychev's inequality float p = variance / (variance + m_d * m_d); p = ReduceLightBleeding(p, Bias.z); // Adjust the light color based on the shadow attenuation shadow *= max(lit_factor, p); This is what I know for certain so far: The lighting is correct if I do not try and calculate the shadow term. (No shadows) The shadow term is correct when calculated using forward rendered lighting. (VSM works with forward rendered lights) With the current rescaled light distance (lightAttenuation.y is the far plane value): float rescaled_dist_to_light = dist_to_light / LightAttenuation.y; The light is correct and the shadow appears to be zoomed in and misses the blurring: When I do not rescale the light and use the homogenized 'surf_tex': float rescaled_dist_to_light = surf_tex.z; the shadows are blurred correctly but the lighting is incorrect and the cube model is no longer lit Why is scaling by the far plane value (LightAttenuation.y) zooming in too far? The only other factor involved is my world pixel position, which is calculated as follows: // [Position] float4 position; // [Screen Position] position.xy = input.PositionClone.xy; // Use 'x' and 'y' components already homogenized for uv coordinates above position.z = tex2D(DepthSampler, texCoord).r; // No need to homogenize 'z' component position.z = 1.0 - position.z; position.w = 1.0; // 1.0 = position.w / position.w // [World Position] position = mul(position, CameraViewProjectionInverse); // Re-homogenize position (xyz AND w, otherwise shadows will bend when camera is close) position.xyz /= position.w; position.w = 1.0; Using the inverse matrix of the camera's view x projection matrix does work for lighting but maybe it is incorrect for shadow calculation? EDIT: Light calculations for shadow including 'dist_to_light' // Work out the light position and direction in world space float3 light_position = float3(LightViewInverse._41, LightViewInverse._42, LightViewInverse._43); // Direction might need to be negated float3 light_direction = float3(-LightViewInverse._31, -LightViewInverse._32, -LightViewInverse._33); // Unnormalized light vector float3 dir_to_light = light_position - position; // Direction from vertex float dist_to_light = length(dir_to_light); // Normalise 'toLight' vector for lighting calculations dir_to_light = normalize(dir_to_light); EDIT2: These are the calculations for the moments (depth) //============================================= //---[Vertex Shaders]-------------------------- //============================================= DepthVSOutput depth_VS( float4 Position : POSITION, uniform float4x4 shadow_view, uniform float4x4 shadow_view_projection) { DepthVSOutput output = (DepthVSOutput)0; // First transform position into world space float4 position_world = mul(Position, World); output.position_screen = mul(position_world, shadow_view_projection); output.light_vec = mul(position_world, shadow_view).xyz; return output; } //============================================= //---[Pixel Shaders]--------------------------- //============================================= DepthPSOutput depth_PS(DepthVSOutput input) { DepthPSOutput output = (DepthPSOutput)0; // Work out the depth of this fragment from the light, normalized to [0, 1] float2 depth; depth.x = length(input.light_vec) / FarPlane; depth.y = depth.x * depth.x; // Flip depth values to avoid floating point inaccuracies depth.x = 1.0f - depth.x; depth.y = 1.0f - depth.y; output.depth = depth.xyxy; return output; } EDIT 3: I have tried the folloiwng: float4 pp; pp.xy = input.PositionClone.xy; // Use 'x' and 'y' components already homogenized for uv coordinates above pp.z = tex2D(DepthSampler, texCoord).r; // No need to homogenize 'z' component pp.z = 1.0 - pp.z; pp.w = 1.0; // 1.0 = position.w / position.w // Determine the depth of the pixel with respect to the light float4x4 LightViewProjection = mul(LightView, LightProjection); float4x4 matViewToLightViewProj = mul(CameraViewProjectionInverse, LightViewProjection); float4 vPositionLightCS = mul(pp, matViewToLightViewProj); float fLightDepth = vPositionLightCS.z / vPositionLightCS.w; // Transform from light space to shadow map texture space. float2 vShadowTexCoord = 0.5 * vPositionLightCS.xy / vPositionLightCS.w + float2(0.5f, 0.5f); vShadowTexCoord.y = 1.0f - vShadowTexCoord.y; // Offset the coordinate by half a texel so we sample it correctly vShadowTexCoord += (0.5f / 512); //g_vShadowMapSize This suffers the same problem as the second picture. I have tried storing the depth based on the view x projection matrix: output.position_screen = mul(position_world, shadow_view_projection); //output.light_vec = mul(position_world, shadow_view); output.light_vec = output.position_screen; depth.x = input.light_vec.z / input.light_vec.w; This gives a shadow that has lots surface acne due to horrible floating point precision errors. Everything is lit correctly though. EDIT 4: Found an OpenGL based tutorial here I have followed it to the letter and it would seem that the uv coordinates for looking up the shadow map are incorrect. The source uses a scaled matrix to get the uv coordinates for the shadow map sampler /// <summary> /// The scale matrix is used to push the projected vertex into the 0.0 - 1.0 region. /// Similar in role to a * 0.5 + 0.5, where -1.0 < a < 1.0. /// <summary> const float4x4 ScaleMatrix = float4x4 ( 0.5, 0.0, 0.0, 0.0, 0.0, -0.5, 0.0, 0.0, 0.0, 0.0, 0.5, 0.0, 0.5, 0.5, 0.5, 1.0 ); I had to negate the 0.5 for the y scaling (M22) in order for it to work but the shadowing is still not correct. Is this really the correct way to scale? float2 shadow_tex; shadow_tex.x = surf_tex.x * 0.5f + 0.5f; shadow_tex.y = surf_tex.y * -0.5f + 0.5f; The depth calculations are exactly the same as the source code yet they still do not work, which makes me believe something about the uv calculation above is incorrect.

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  • A Good Developer is So Hard to Find

    - by James Michael Hare
    Let me start out by saying I want to damn the writers of the Toughest Developer Puzzle Ever – 2. It is eating every last shred of my free time! But as I've been churning through each puzzle and marvelling at the brain teasers and trivia within, I began to think about interviewing developers and why it seems to be so hard to find good ones.  The problem is, it seems like no matter how hard we try to find the perfect way to separate the chaff from the wheat, inevitably someone will get hired who falls far short of expectations or someone will get passed over for missing a piece of trivia or a tricky brain teaser that could have been an excellent team member.   In shops that are primarily software-producing businesses or other heavily IT-oriented businesses (Microsoft, Amazon, etc) there often exists a much tighter bond between HR and the hiring development staff because development is their life-blood. Unfortunately, many of us work in places where IT is viewed as a cost or just a means to an end. In these shops, too often, HR and development staff may work against each other due to differences in opinion as to what a good developer is or what one is worth.  It seems that if you ask two different people what makes a good developer, often you will get three different opinions.   With the exception of those shops that are purely development-centric (you guys have it much easier!), most other shops have management who have very little knowledge about the development process.  Their view can often be that development is simply a skill that one learns and then once aquired, that developer can produce widgets as good as the next like workers on an assembly-line floor.  On the other side, you have many developers that feel that software development is an art unto itself and that the ability to create the most pure design or know the most obscure of keywords or write the shortest-possible obfuscated piece of code is a good coder.  So is it a skill?  An Art?  Or something entirely in between?   Saying that software is merely a skill and one just needs to learn the syntax and tools would be akin to saying anyone who knows English and can use Word can write a 300 page book that is accurate, meaningful, and stays true to the point.  This just isn't so.  It takes more than mere skill to take words and form a sentence, join those sentences into paragraphs, and those paragraphs into a document.  I've interviewed candidates who could answer obscure syntax and keyword questions and once they were hired could not code effectively at all.  So development must be more than a skill.   But on the other end, we have art.  Is development an art?  Is our end result to produce art?  I can marvel at a piece of code -- see it as concise and beautiful -- and yet that code most perform some stated function with accuracy and efficiency and maintainability.  None of these three things have anything to do with art, per se.  Art is beauty for its own sake and is a wonderful thing.  But if you apply that same though to development it just doesn't hold.  I've had developers tell me that all that matters is the end result and how you code it is entirely part of the art and I couldn't disagree more.  Yes, the end result, the accuracy, is the prime criteria to be met.  But if code is not maintainable and efficient, it would be just as useless as a beautiful car that breaks down once a week or that gets 2 miles to the gallon.  Yes, it may work in that it moves you from point A to point B and is pretty as hell, but if it can't be maintained or is not efficient, it's not a good solution.  So development must be something less than art.   In the end, I think I feel like development is a matter of craftsmanship.  We use our tools and we use our skills and set about to construct something that satisfies a purpose and yet is also elegant and efficient.  There is skill involved, and there is an art, but really it boils down to being able to craft code.  Crafting code is far more than writing code.  Anyone can write code if they know the syntax, but so few people can actually craft code that solves a purpose and craft it well.  So this is what I want to find, I want to find code craftsman!  But how?   I used to ask coding-trivia questions a long time ago and many people still fall back on this.  The thought is that if you ask the candidate some piece of coding trivia and they know the answer it must follow that they can craft good code.  For example:   What C++ keyword can be applied to a class/struct field to allow it to be changed even from a const-instance of that class/struct?  (answer: mutable)   So what do we prove if a candidate can answer this?  Only that they know what mutable means.  One would hope that this would infer that they'd know how to use it, and more importantly when and if it should ever be used!  But it rarely does!  The problem with triva questions is that you will either: Approve a really good developer who knows what some obscure keyword is (good) Reject a really good developer who never needed to use that keyword or is too inexperienced to know how to use it (bad) Approve a really bad developer who googled "C++ Interview Questions" and studied like hell but can't craft (very bad) Many HR departments love these kind of tests because they are short and easy to defend if a legal issue arrises on hiring decisions.  After all it's easy to say a person wasn't hired because they scored 30 out of 100 on some trivia test.  But unfortunately, you've eliminated a large part of your potential developer pool and possibly hired a few duds.  There are times I've hired candidates who knew every trivia question I could throw out them and couldn't craft.  And then there are times I've interviewed candidates who failed all my trivia but who I took a chance on who were my best finds ever.    So if not trivia, then what?  Brain teasers?  The thought is, these type of questions measure the thinking power of a candidate.  The problem is, once again, you will either: Approve a good candidate who has never heard the problem and can solve it (good) Reject a good candidate who just happens not to see the "catch" because they're nervous or it may be really obscure (bad) Approve a candidate who has studied enough interview brain teasers (once again, you can google em) to recognize the "catch" or knows the answer already (bad). Once again, you're eliminating good candidates and possibly accepting bad candidates.  In these cases, I think testing someone with brain teasers only tests their ability to answer brain teasers, not the ability to craft code. So how do we measure someone's ability to craft code?  Here's a novel idea: have them code!  Give them a computer and a compiler, or a whiteboard and a pen, or paper and pencil and have them construct a piece of code.  It just makes sense that if we're going to hire someone to code we should actually watch them code.  When they're done, we can judge them on several criteria: Correctness - does the candidate's solution accurately solve the problem proposed? Accuracy - is the candidate's solution reasonably syntactically correct? Efficiency - did the candidate write or use the more efficient data structures or algorithms for the job? Maintainability - was the candidate's code free of obfuscation and clever tricks that diminish readability? Persona - are they eager and willing or aloof and egotistical?  Will they work well within your team? It may sound simple, or it may sound crazy, but when I'm looking to hire a developer, I want to see them actually develop well-crafted code.

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  • SSAO Distortion

    - by Robert Xu
    I'm currently (attempting) to add SSAO to my engine, except it's...not really work, to say the least. I use a deferred renderer to render my scene. I have four render targets: Albedo, Light, Normal, and Depth. Here are the parameters for all of them (Surface Format, Depth Format): Albedo: 32-bit ARGB, Depth24Stencil8 Light: 32-bit ARGB, None Normal: 32-bit ARGB, None Depth: 8-bit R (Single), Depth24Stencil8 To generate my random noise map for the SSAO, I do the following for each pixel in the noise map: Vector3 v3 = Vector3.Zero; double z = rand.NextDouble() * 2.0 - 1.0; double r = Math.Sqrt(1.0 - z * z); double angle = rand.NextDouble() * MathHelper.TwoPi; v3.X = (float)(r * Math.Cos(angle)); v3.Y = (float)(r * Math.Sin(angle)); v3.Z = (float)z; v3 += offset; v3 *= 0.5f; result[i] = new Color(v3); This is my GBuffer rendering effect: PixelInput RenderGBufferColorVertexShader(VertexInput input) { PixelInput pi = ( PixelInput ) 0; pi.Position = mul(input.Position, WorldViewProjection); pi.Normal = mul(input.Normal, WorldInverseTranspose); pi.Color = input.Color; pi.TPosition = pi.Position; pi.WPosition = input.Position; return pi; } GBufferTarget RenderGBufferColorPixelShader(PixelInput input) { GBufferTarget output = ( GBufferTarget ) 0; float3 position = input.TPosition.xyz / input.TPosition.w; output.Albedo = lerp(float4(1.0f, 1.0f, 1.0f, 1.0f), input.Color, ColorFactor); output.Normal = EncodeNormal(input.Normal); output.Depth = position.z; return output; } And here is the SSAO effect: float4 EncodeNormal(float3 normal) { return float4((normal.xyz * 0.5f) + 0.5f, 0.0f); } float3 DecodeNormal(float4 encoded) { return encoded * 2.0 - 1.0f; } float Intensity; float Size; float2 NoiseOffset; float4x4 ViewProjection; float4x4 ViewProjectionInverse; texture DepthMap; texture NormalMap; texture RandomMap; const float3 samples[16] = { float3(0.01537562, 0.01389096, 0.02276565), float3(-0.0332658, -0.2151698, -0.0660736), float3(-0.06420016, -0.1919067, 0.5329634), float3(-0.05896204, -0.04509097, -0.03611697), float3(-0.1302175, 0.01034653, 0.01543675), float3(0.3168565, -0.182557, -0.01421785), float3(-0.02134448, -0.1056605, 0.00576055), float3(-0.3502164, 0.281433, -0.2245609), float3(-0.00123525, 0.00151868, 0.02614773), float3(0.1814744, 0.05798516, -0.02362876), float3(0.07945167, -0.08302628, 0.4423518), float3(0.321987, -0.05670302, -0.05418307), float3(-0.00165138, -0.00410309, 0.00537362), float3(0.01687791, 0.03189049, -0.04060405), float3(-0.04335613, -0.00530749, 0.06443053), float3(0.8474263, -0.3590308, -0.02318038), }; sampler DepthSampler = sampler_state { Texture = DepthMap; MipFilter = Point; MinFilter = Point; MagFilter = Point; AddressU = Clamp; AddressV = Clamp; AddressW = Clamp; }; sampler NormalSampler = sampler_state { Texture = NormalMap; MipFilter = Linear; MinFilter = Linear; MagFilter = Linear; AddressU = Clamp; AddressV = Clamp; AddressW = Clamp; }; sampler RandomSampler = sampler_state { Texture = RandomMap; MipFilter = Linear; MinFilter = Linear; MagFilter = Linear; }; struct VertexInput { float4 Position : POSITION0; float2 TextureCoordinates : TEXCOORD0; }; struct PixelInput { float4 Position : POSITION0; float2 TextureCoordinates : TEXCOORD0; }; PixelInput SSAOVertexShader(VertexInput input) { PixelInput pi = ( PixelInput ) 0; pi.Position = input.Position; pi.TextureCoordinates = input.TextureCoordinates; return pi; } float3 GetXYZ(float2 uv) { float depth = tex2D(DepthSampler, uv); float2 xy = uv * 2.0f - 1.0f; xy.y *= -1; float4 p = float4(xy, depth, 1); float4 q = mul(p, ViewProjectionInverse); return q.xyz / q.w; } float3 GetNormal(float2 uv) { return DecodeNormal(tex2D(NormalSampler, uv)); } float4 SSAOPixelShader(PixelInput input) : COLOR0 { float depth = tex2D(DepthSampler, input.TextureCoordinates); float3 position = GetXYZ(input.TextureCoordinates); float3 normal = GetNormal(input.TextureCoordinates); float occlusion = 1.0f; float3 reflectionRay = DecodeNormal(tex2D(RandomSampler, input.TextureCoordinates + NoiseOffset)); for (int i = 0; i < 16; i++) { float3 sampleXYZ = position + reflect(samples[i], reflectionRay) * Size; float4 screenXYZW = mul(float4(sampleXYZ, 1.0f), ViewProjection); float3 screenXYZ = screenXYZW.xyz / screenXYZW.w; float2 sampleUV = float2(screenXYZ.x * 0.5f + 0.5f, 1.0f - (screenXYZ.y * 0.5f + 0.5f)); float frontMostDepthAtSample = tex2D(DepthSampler, sampleUV); if (frontMostDepthAtSample < screenXYZ.z) { occlusion -= 1.0f / 16.0f; } } return float4(occlusion * Intensity * float3(1.0, 1.0, 1.0), 1.0); } technique SSAO { pass Pass0 { VertexShader = compile vs_3_0 SSAOVertexShader(); PixelShader = compile ps_3_0 SSAOPixelShader(); } } However, when I use the effect, I get some pretty bad distortion: Here's the light map that goes with it -- is the static-like effect supposed to be like that? I've noticed that even if I'm looking at nothing, I still get the static-like effect. (you can see it in the screenshot; the top half doesn't have any geometry yet it still has the static-like effect) Also, does anyone have any advice on how to effectively debug shaders?

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  • how to use serial port in UDK using windows DLL and DLLBind directive?

    - by Shayan Abbas
    I want to use serial port in UDK, For that purpose i use a windows DLL and DLLBind directive. I have a thread in windows DLL for serial port data recieve event. My problem is: this thread doesn't work properly. Please Help me. below is my code SerialPortDLL Code: // SerialPortDLL.cpp : Defines the exported functions for the DLL application. // #include "stdafx.h" #include "Cport.h" extern "C" { // This is an example of an exported variable //SERIALPORTDLL_API int nSerialPortDLL=0; // This is an example of an exported function. //SERIALPORTDLL_API int fnSerialPortDLL(void) //{ // return 42; //} CPort *sp; __declspec(dllexport) void Open(wchar_t* portName) { sp = new CPort(portName); //MessageBox(0,L"ha ha!!!",L"ha ha",0); //MessageBox(0,portName,L"ha ha",0); } __declspec(dllexport) void Close() { sp->Close(); MessageBox(0,L"ha ha!!!",L"ha ha",0); } __declspec(dllexport) wchar_t *GetData() { return sp->GetData(); } __declspec(dllexport) unsigned int GetDSR() { return sp->getDSR(); } __declspec(dllexport) unsigned int GetCTS() { return sp->getCTS(); } __declspec(dllexport) unsigned int GetRing() { return sp->getRing(); } } CPort class code: #include "stdafx.h" #include "CPort.h" #include "Serial.h" CSerial serial; HANDLE HandleOfThread; LONG lLastError = ERROR_SUCCESS; bool fContinue = true; HANDLE hevtOverlapped; HANDLE hevtStop; OVERLAPPED ov = {0}; //char szBuffer[101] = ""; wchar_t *szBuffer = L""; wchar_t *data = L""; DWORD WINAPI ThreadHandler( LPVOID lpParam ) { // Keep reading data, until an EOF (CTRL-Z) has been received do { MessageBox(0,L"ga ga!!!",L"ga ga",0); //Sleep(10); // Wait for an event lLastError = serial.WaitEvent(&ov); if (lLastError != ERROR_SUCCESS) { //LOG( " Unable to wait for a COM-port event" ); } // Setup array of handles in which we are interested HANDLE ahWait[2]; ahWait[0] = hevtOverlapped; ahWait[1] = hevtStop; // Wait until something happens switch (::WaitForMultipleObjects(sizeof(ahWait)/sizeof(*ahWait),ahWait,FALSE,INFINITE)) { case WAIT_OBJECT_0: { // Save event const CSerial::EEvent eEvent = serial.GetEventType(); // Handle break event if (eEvent & CSerial::EEventBreak) { //LOG( " ### BREAK received ###" ); } // Handle CTS event if (eEvent & CSerial::EEventCTS) { //LOG( " ### Clear to send %s ###", serial.GetCTS() ? "on":"off" ); } // Handle DSR event if (eEvent & CSerial::EEventDSR) { //LOG( " ### Data set ready %s ###", serial.GetDSR() ? "on":"off" ); } // Handle error event if (eEvent & CSerial::EEventError) { switch (serial.GetError()) { case CSerial::EErrorBreak: /*LOG( " Break condition" );*/ break; case CSerial::EErrorFrame: /*LOG( " Framing error" );*/ break; case CSerial::EErrorIOE: /*LOG( " IO device error" );*/ break; case CSerial::EErrorMode: /*LOG( " Unsupported mode" );*/ break; case CSerial::EErrorOverrun: /*LOG( " Buffer overrun" );*/ break; case CSerial::EErrorRxOver: /*LOG( " Input buffer overflow" );*/ break; case CSerial::EErrorParity: /*LOG( " Input parity error" );*/ break; case CSerial::EErrorTxFull: /*LOG( " Output buffer full" );*/ break; default: /*LOG( " Unknown" );*/ break; } } // Handle ring event if (eEvent & CSerial::EEventRing) { //LOG( " ### RING ###" ); } // Handle RLSD/CD event if (eEvent & CSerial::EEventRLSD) { //LOG( " ### RLSD/CD %s ###", serial.GetRLSD() ? "on" : "off" ); } // Handle data receive event if (eEvent & CSerial::EEventRecv) { // Read data, until there is nothing left DWORD dwBytesRead = 0; do { // Read data from the COM-port lLastError = serial.Read(szBuffer,33,&dwBytesRead); if (lLastError != ERROR_SUCCESS) { //LOG( "Unable to read from COM-port" ); } if( dwBytesRead == 33 && szBuffer[0]=='$' ) { // Finalize the data, so it is a valid string szBuffer[dwBytesRead] = '\0'; ////LOG( "\n%s\n", szBuffer ); data = szBuffer; } } while (dwBytesRead > 0); } } break; case WAIT_OBJECT_0+1: { // Set the continue bit to false, so we'll exit fContinue = false; } break; default: { // Something went wrong //LOG( "Error while calling WaitForMultipleObjects" ); } break; } } while (fContinue); MessageBox(0,L"kka kk!!!",L"kka ga",0); return 0; } CPort::CPort(wchar_t *portName) { // Attempt to open the serial port (COM2) //lLastError = serial.Open(_T(portName),0,0,true); lLastError = serial.Open(portName,0,0,true); if (lLastError != ERROR_SUCCESS) { //LOG( "Unable to open COM-port" ); } // Setup the serial port (115200,8N1, which is the default setting) lLastError = serial.Setup(CSerial::EBaud115200,CSerial::EData8,CSerial::EParNone,CSerial::EStop1); if (lLastError != ERROR_SUCCESS) { //LOG( "Unable to set COM-port setting" ); } // Register only for the receive event lLastError = serial.SetMask(CSerial::EEventBreak | CSerial::EEventCTS | CSerial::EEventDSR | CSerial::EEventError | CSerial::EEventRing | CSerial::EEventRLSD | CSerial::EEventRecv); if (lLastError != ERROR_SUCCESS) { //LOG( "Unable to set COM-port event mask" ); } // Use 'non-blocking' reads, because we don't know how many bytes // will be received. This is normally the most convenient mode // (and also the default mode for reading data). lLastError = serial.SetupReadTimeouts(CSerial::EReadTimeoutNonblocking); if (lLastError != ERROR_SUCCESS) { //LOG( "Unable to set COM-port read timeout" ); } // Create a handle for the overlapped operations hevtOverlapped = ::CreateEvent(0,TRUE,FALSE,0);; if (hevtOverlapped == 0) { //LOG( "Unable to create manual-reset event for overlapped I/O" ); } // Setup the overlapped structure ov.hEvent = hevtOverlapped; // Open the "STOP" handle hevtStop = ::CreateEvent(0,TRUE,FALSE,_T("Overlapped_Stop_Event")); if (hevtStop == 0) { //LOG( "Unable to create manual-reset event for stop event" ); } HandleOfThread = CreateThread( NULL, 0, ThreadHandler, 0, 0, NULL); } CPort::~CPort() { //fContinue = false; //CloseHandle( HandleOfThread ); //serial.Close(); } void CPort::Close() { fContinue = false; CloseHandle( HandleOfThread ); serial.Close(); } wchar_t *CPort::GetData() { return data; } bool CPort::getCTS() { return serial.GetCTS(); } bool CPort::getDSR() { return serial.GetDSR(); } bool CPort::getRing() { return serial.GetRing(); } Unreal Script Code: class MyPlayerController extends GamePlayerController DLLBind(SerialPortDLL); dllimport final function Open(string portName); dllimport final function Close(); dllimport final function string GetData();

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  • OpenGL font rendering

    - by DEElekgolo
    I am trying to make an openGL text rendering class using FreeType. I was originally following this code but it doesn't seem to work out for me. I get nothing reguardless of what parameters I put for Draw(). class Font { public: Font() { if (FT_Init_FreeType(&ftLibrary)) { printf("Could not initialize FreeType library\n"); return; } glGenBuffers(1,&iVerts); } bool Load(std::string sFont, unsigned int Size = 12.0f) { if (FT_New_Face(ftLibrary,sFont.c_str(),0,&ftFace)) { printf("Could not open font: %s\n",sFont.c_str()); return true; } iSize = Size; FT_Set_Pixel_Sizes(ftFace,0,(int)iSize); FT_GlyphSlot gGlyph = ftFace->glyph; //Generating the texture atlas. //Rather than some amazing rectangular packing method, I'm just going //to have one long strip of letters with the height being that of the font size. int width = 0; int height = 0; for (int i = 32; i < 128; i++) { if (FT_Load_Char(ftFace,i,FT_LOAD_RENDER)) { printf("Error rendering letter %c for font %s.\n",i,sFont.c_str()); } width += gGlyph->bitmap.width; height += std::max(height,gGlyph->bitmap.rows); } //Generate the openGL texture glActiveTexture(GL_TEXTURE0); //if I texture exists then delete it. iTexture ? glDeleteBuffers(1,&iTexture):0; glGenTextures(1,&iTexture); glBindTexture(GL_TEXTURE_2D,iTexture); glPixelStorei(GL_UNPACK_ALIGNMENT,1); glTexImage2D(GL_TEXTURE_2D,0,GL_ALPHA,width,height,0,GL_ALPHA,GL_UNSIGNED_BYTE,0); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR); //load the glyphs and set the glyph data int x = 0; for (int i = 32; i < 128; i++) { if (FT_Load_Char(ftFace,i,FT_LOAD_RENDER)) { //if it cant load the character continue; } //load the glyph map into the texture glTexSubImage2D(GL_TEXTURE_2D,0,x,0, gGlyph->bitmap.width, gGlyph->bitmap.rows, GL_ALPHA, GL_UNSIGNED_BYTE, gGlyph->bitmap.buffer); //move the "pen" down the strip x += gGlyph->bitmap.width; chars[i].ax = (float)(gGlyph->advance.x >> 6); chars[i].ay = (float)(gGlyph->advance.y >> 6); chars[i].bw = (float)gGlyph->bitmap.width; chars[i].bh = (float)gGlyph->bitmap.rows; chars[i].bl = (float)gGlyph->bitmap_left; chars[i].bt = (float)gGlyph->bitmap_top; chars[i].tx = (float)x/width; } printf("Loaded font: %s\n",sFont.c_str()); return true; } void Draw(std::string sString,Vector2f vPos = Vector2f(0,0),Vector2f vScale = Vector2f(1,1)) { struct pPoint { pPoint() { x = y = s = t = 0; } pPoint(float a,float b,float c,float d) { x = a; y = b; s = c; t = d; } float x,y; float s,t; }; pPoint* cCoordinates = new pPoint[6*sString.length()]; int n = 0; for (const char *p = sString.c_str(); *p; p++) { float x2 = vPos.x() + chars[*p].bl * vScale.x(); float y2 = -vPos.y() - chars[*p].bt * vScale.y(); float w = chars[*p].bw * vScale.x(); float h = chars[*p].bh * vScale.y(); float x = vPos.x() + chars[*p].ax * vScale.x(); float y = vPos.y() + chars[*p].ay * vScale.y(); //skip characters with no pixels //still advances though if (!w || !h) { continue; } //triangle one cCoordinates[n++] = pPoint( x2 , -y2 , chars[*p].tx , 0); cCoordinates[n++] = pPoint( x2+w , -y2 , chars[*p].tx + chars[*p].bw / w , 0); cCoordinates[n++] = pPoint( x2 , -y2-h , chars[*p].tx , chars[*p].bh / h); cCoordinates[n++] = pPoint( x2+w , -y2 , chars[*p].tx + chars[*p].bw / w , 0); cCoordinates[n++] = pPoint( x2 , -y2-h , chars[*p].tx , chars[*p].bh / h); cCoordinates[n++] = pPoint( x2+w , -y2-h , chars[*p].tx + chars[*p].bw / w , chars[*p].bh / h); } glBindBuffer(GL_ARRAY_BUFFER,iVerts); glBindBuffer(GL_TEXTURE_2D,iTexture); //Vertices glEnableClientState(GL_VERTEX_ARRAY); glVertexPointer(2,GL_FLOAT,sizeof(pPoint),&cCoordinates[0].x); //TexCoord 0 glClientActiveTexture(GL_TEXTURE0); glEnableClientState(GL_TEXTURE_COORD_ARRAY); glTexCoordPointer(2,GL_FLOAT,sizeof(pPoint),&cCoordinates[0].s); glCullFace(GL_NONE); glBufferData(GL_ARRAY_BUFFER,6*sString.length(),cCoordinates,GL_DYNAMIC_DRAW); glDrawArrays(GL_TRIANGLES,0,n); glCullFace(GL_BACK); glBindBuffer(GL_ARRAY_BUFFER,0); glBindBuffer(GL_TEXTURE_2D,0); glDisableClientState(GL_VERTEX_ARRAY); glDisableClientState(GL_TEXTURE_COORD_ARRAY); } ~Font() { glDeleteBuffers(1,&iVerts); glDeleteBuffers(1,&iTexture); } private: unsigned int iSize; //openGL texture atlas unsigned int iTexture; //openGL geometry buffer; unsigned int iVerts; FT_Library ftLibrary; FT_Face ftFace; struct Character { float ax,ay;//Advance float bw,bh;//bitmap size float bl,bt;//bitmap left and top float tx; } chars[128]; };

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  • RIF PRD: Presentation syntax issues

    - by Charles Young
    Over Christmas I got to play a bit with the W3C RIF PRD and came across a few issues which I thought I would record for posterity. Specifically, I was working on a grammar for the presentation syntax using a GLR grammar parser tool (I was using the current CTP of ‘M’ (MGrammer) and Intellipad – I do so hope the MS guys don’t kill off M and Intellipad now they have dropped the other parts of SQL Server Modelling). I realise that the presentation syntax is non-normative and that any issues with it do not therefore compromise the standard. However, presentation syntax is useful in its own right, and it would be great to iron out any issues in a future revision of the standard. The main issues are actually not to do with the grammar at all, but rather with the ‘running example’ in the RIF PRD recommendation. I started with the code provided in Example 9.1. There are several discrepancies when compared with the EBNF rules documented in the standard. Broadly the problems can be categorised as follows: ·      Parenthesis mismatch – the wrong number of parentheses are used in various places. For example, in GoldRule, the RHS of the rule (the ‘Then’) is nested in the LHS (‘the If’). In NewCustomerAndWidgetRule, the RHS is orphaned from the LHS. Together with additional incorrect parenthesis, this leads to orphanage of UnknownStatusRule from the entire Document. ·      Invalid use of parenthesis in ‘Forall’ constructs. Parenthesis should not be used to enclose formulae. Removal of the invalid parenthesis gave me a feeling of inconsistency when comparing formulae in Forall to formulae in If. The use of parenthesis is not actually inconsistent in these two context, but in an If construct it ‘feels’ as if you are enclosing formulae in parenthesis in a LISP-like fashion. In reality, the parenthesis is simply being used to group subordinate syntax elements. The fact that an If construct can contain only a single formula as an immediate child adds to this feeling of inconsistency. ·      Invalid representation of compact URIs (CURIEs) in the context of Frame productions. In several places the URIs are not qualified with a namespace prefix (‘ex1:’). This conflicts with the definition of CURIEs in the RIF Datatypes and Built-Ins 1.0 document. Here are the productions: CURIE          ::= PNAME_LN                  | PNAME_NS PNAME_LN       ::= PNAME_NS PN_LOCAL PNAME_NS       ::= PN_PREFIX? ':' PN_LOCAL       ::= ( PN_CHARS_U | [0-9] ) ((PN_CHARS|'.')* PN_CHARS)? PN_CHARS       ::= PN_CHARS_U                  | '-' | [0-9] | #x00B7                  | [#x0300-#x036F] | [#x203F-#x2040] PN_CHARS_U     ::= PN_CHARS_BASE                  | '_' PN_CHARS_BASE ::= [A-Z] | [a-z] | [#x00C0-#x00D6] | [#x00D8-#x00F6]                  | [#x00F8-#x02FF] | [#x0370-#x037D] | [#x037F-#x1FFF]                  | [#x200C-#x200D] | [#x2070-#x218F] | [#x2C00-#x2FEF]                  | [#x3001-#xD7FF] | [#xF900-#xFDCF] | [#xFDF0-#xFFFD]                  | [#x10000-#xEFFFF] PN_PREFIX      ::= PN_CHARS_BASE ((PN_CHARS|'.')* PN_CHARS)? The more I look at CURIEs, the more my head hurts! The RIF specification allows prefixes and colons without local names, which surprised me. However, the CURIE Syntax 1.0 working group note specifically states that this form is supported…and then promptly provides a syntactic definition that seems to preclude it! However, on (much) deeper inspection, it appears that ‘ex1:’ (for example) is allowed, but would really represent a ‘fragment’ of the ‘reference’, rather than a prefix! Ouch! This is so completely ambiguous that it surely calls into question the whole CURIE specification.   In any case, RIF does not allow local names without a prefix. ·      Missing ‘External’ specifiers for built-in functions and predicates.  The EBNF specification enforces this for terms within frames, but does not appear to enforce (what I believe is) the correct use of External on built-in predicates. In any case, the running example only specifies ‘External’ once on the predicate in UnknownStatusRule. External() is required in several other places. ·      The List used on the LHS of UnknownStatusRule is comma-delimited. This is not supported by the EBNF definition. Similarly, the argument list of pred:list-contains is illegally comma-delimited. ·      Unnecessary use of conjunction around a single formula in DiscountRule. This is strictly legal in the EBNF, but redundant.   All the above issues concern the presentation syntax used in the running example. There are a few minor issues with the grammar itself. Note that Michael Kiefer stated in his paper “Rule Interchange Format: The Framework” that: “The presentation syntax of RIF … is an abstract syntax and, as such, it omits certain details that might be important for unambiguous parsing.” ·      The grammar cannot differentiate unambiguously between strategies and priorities on groups. A processor is forced to resolve this by detecting the use of IRIs and integers. This could easily be fixed in the grammar.   ·      The grammar cannot unambiguously parse the ‘->’ operator in frames. Specifically, ‘-’ characters are allowed in PN_LOCAL names and hence a parser cannot determine if ‘status->’ is (‘status’ ‘->’) or (‘status-’ ‘>’).   One way to fix this is to amend the PN_LOCAL production as follows: PN_LOCAL ::= ( PN_CHARS_U | [0-9] ) ((PN_CHARS|'.')* ((PN_CHARS)-('-')))? However, unilaterally changing the definition of this production, which is defined in the SPARQL Query Language for RDF specification, makes me uncomfortable. ·      I assume that the presentation syntax is case-sensitive. I couldn’t find this stated anywhere in the documentation, but function/predicate names do appear to be documented as being case-sensitive. ·      The EBNF does not specify whitespace handling. A couple of productions (RULE and ACTION_BLOCK) are crafted to enforce the use of whitespace. This is not necessary. It seems inconsistent with the rest of the specification and can cause parsing issues. In addition, the Const production exhibits whitespaces issues. The intention may have been to disallow the use of whitespace around ‘^^’, but any direct implementation of the EBNF will probably allow whitespace between ‘^^’ and the SYMSPACE. Of course, I am being a little nit-picking about all this. On the whole, the EBNF translated very smoothly and directly to ‘M’ (MGrammar) and proved to be fairly complete. I have encountered far worse issues when translating other EBNF specifications into usable grammars.   I can’t imagine there would be any difficulty in implementing the same grammar in Antlr, COCO/R, gppg, XText, Bison, etc. A general observation, which repeats a point made above, is that the use of parenthesis in the presentation syntax can feel inconsistent and un-intuitive.   It isn’t actually inconsistent, but I think the presentation syntax could be improved by adopting braces, rather than parenthesis, to delimit subordinate syntax elements in a similar way to so many programming languages. The familiarity of braces would communicate the structure of the syntax more clearly to people like me.  If braces were adopted, parentheses could be retained around ‘var (frame | ‘new()’) constructs in action blocks. This use of parenthesis feels very LISP-like, and I think that this is my issue. It’s as if the presentation syntax represents the deformed love-child of LISP and C. In some places (specifically, action blocks), parenthesis is used in a LISP-like fashion. In other places it is used like braces in C. I find this quite confusing. Here is a corrected version of the running example (Example 9.1) in compliant presentation syntax: Document(    Prefix( ex1 <http://example.com/2009/prd2> )    (* ex1:CheckoutRuleset *)  Group rif:forwardChaining (     (* ex1:GoldRule *)    Group 10 (      Forall ?customer such that And(?customer # ex1:Customer                                     ?customer[ex1:status->"Silver"])        (Forall ?shoppingCart such that ?customer[ex1:shoppingCart->?shoppingCart]           (If Exists ?value (And(?shoppingCart[ex1:value->?value]                                  External(pred:numeric-greater-than-or-equal(?value 2000))))            Then Do(Modify(?customer[ex1:status->"Gold"])))))      (* ex1:DiscountRule *)    Group (      Forall ?customer such that ?customer # ex1:Customer        (If Or( ?customer[ex1:status->"Silver"]                ?customer[ex1:status->"Gold"])         Then Do ((?s ?customer[ex1:shoppingCart-> ?s])                  (?v ?s[ex1:value->?v])                  Modify(?s [ex1:value->External(func:numeric-multiply (?v 0.95))]))))      (* ex1:NewCustomerAndWidgetRule *)    Group (      Forall ?customer such that And(?customer # ex1:Customer                                     ?customer[ex1:status->"New"] )        (If Exists ?shoppingCart ?item                   (And(?customer[ex1:shoppingCart->?shoppingCart]                        ?shoppingCart[ex1:containsItem->?item]                        ?item # ex1:Widget ) )         Then Do( (?s ?customer[ex1:shoppingCart->?s])                  (?val ?s[ex1:value->?val])                  (?voucher ?customer[ex1:voucher->?voucher])                  Retract(?customer[ex1:voucher->?voucher])                  Retract(?voucher)                  Modify(?s[ex1:value->External(func:numeric-multiply(?val 0.90))]))))      (* ex1:UnknownStatusRule *)    Group (      Forall ?customer such that ?customer # ex1:Customer        (If Not(Exists ?status                       (And(?customer[ex1:status->?status]                            External(pred:list-contains(List("New" "Bronze" "Silver" "Gold") ?status)) )))         Then Do( Execute(act:print(External(func:concat("New customer: " ?customer))))                  Assert(?customer[ex1:status->"New"]))))  ) )   I hope that helps someone out there :-)

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  • My vertex shader doesn't affect texture coords or diffuse info but works for position

    - by tina nyaa
    I am new to 3D and DirectX - in the past I have only used abstractions for 2D drawing. Over the past month I've been studying really hard and I'm trying to modify and adapt some of the shaders as part of my personal 'study project'. Below I have a shader, modified from one of the Microsoft samples. I set diffuse and tex0 vertex shader outputs to zero, but my model still shows the full texture and lighting as if I hadn't changed the values from the vertex buffer. Changing the position of the model works, but nothing else. Why is this? // // Skinned Mesh Effect file // Copyright (c) 2000-2002 Microsoft Corporation. All rights reserved. // float4 lhtDir = {0.0f, 0.0f, -1.0f, 1.0f}; //light Direction float4 lightDiffuse = {0.6f, 0.6f, 0.6f, 1.0f}; // Light Diffuse float4 MaterialAmbient : MATERIALAMBIENT = {0.1f, 0.1f, 0.1f, 1.0f}; float4 MaterialDiffuse : MATERIALDIFFUSE = {0.8f, 0.8f, 0.8f, 1.0f}; // Matrix Pallette static const int MAX_MATRICES = 100; float4x3 mWorldMatrixArray[MAX_MATRICES] : WORLDMATRIXARRAY; float4x4 mViewProj : VIEWPROJECTION; /////////////////////////////////////////////////////// struct VS_INPUT { float4 Pos : POSITION; float4 BlendWeights : BLENDWEIGHT; float4 BlendIndices : BLENDINDICES; float3 Normal : NORMAL; float3 Tex0 : TEXCOORD0; }; struct VS_OUTPUT { float4 Pos : POSITION; float4 Diffuse : COLOR; float2 Tex0 : TEXCOORD0; }; float3 Diffuse(float3 Normal) { float CosTheta; // N.L Clamped CosTheta = max(0.0f, dot(Normal, lhtDir.xyz)); // propogate scalar result to vector return (CosTheta); } VS_OUTPUT VShade(VS_INPUT i, uniform int NumBones) { VS_OUTPUT o; float3 Pos = 0.0f; float3 Normal = 0.0f; float LastWeight = 0.0f; // Compensate for lack of UBYTE4 on Geforce3 int4 IndexVector = D3DCOLORtoUBYTE4(i.BlendIndices); // cast the vectors to arrays for use in the for loop below float BlendWeightsArray[4] = (float[4])i.BlendWeights; int IndexArray[4] = (int[4])IndexVector; // calculate the pos/normal using the "normal" weights // and accumulate the weights to calculate the last weight for (int iBone = 0; iBone < NumBones-1; iBone++) { LastWeight = LastWeight + BlendWeightsArray[iBone]; Pos += mul(i.Pos, mWorldMatrixArray[IndexArray[iBone]]) * BlendWeightsArray[iBone]; Normal += mul(i.Normal, mWorldMatrixArray[IndexArray[iBone]]) * BlendWeightsArray[iBone]; } LastWeight = 1.0f - LastWeight; // Now that we have the calculated weight, add in the final influence Pos += (mul(i.Pos, mWorldMatrixArray[IndexArray[NumBones-1]]) * LastWeight); Normal += (mul(i.Normal, mWorldMatrixArray[IndexArray[NumBones-1]]) * LastWeight); // transform position from world space into view and then projection space //o.Pos = mul(float4(Pos.xyz, 1.0f), mViewProj); o.Pos = mul(float4(Pos.xyz, 1.0f), mViewProj); o.Diffuse.x = 0.0f; o.Diffuse.y = 0.0f; o.Diffuse.z = 0.0f; o.Diffuse.w = 0.0f; o.Tex0 = float2(0,0); return o; } technique t0 { pass p0 { VertexShader = compile vs_3_0 VShade(4); } } I am currently using the SlimDX .NET wrapper around DirectX, but the API is extremely similar: public void Draw() { var device = vertexBuffer.Device; device.Clear(ClearFlags.Target | ClearFlags.ZBuffer, Color.White, 1.0f, 0); device.SetRenderState(RenderState.Lighting, true); device.SetRenderState(RenderState.DitherEnable, true); device.SetRenderState(RenderState.ZEnable, true); device.SetRenderState(RenderState.CullMode, Cull.Counterclockwise); device.SetRenderState(RenderState.NormalizeNormals, true); device.SetSamplerState(0, SamplerState.MagFilter, TextureFilter.Anisotropic); device.SetSamplerState(0, SamplerState.MinFilter, TextureFilter.Anisotropic); device.SetTransform(TransformState.World, Matrix.Identity * Matrix.Translation(0, -50, 0)); device.SetTransform(TransformState.View, Matrix.LookAtLH(new Vector3(-200, 0, 0), Vector3.Zero, Vector3.UnitY)); device.SetTransform(TransformState.Projection, Matrix.PerspectiveFovLH((float)Math.PI / 4, (float)device.Viewport.Width / device.Viewport.Height, 10, 10000000)); var material = new Material(); material.Ambient = material.Diffuse = material.Emissive = material.Specular = new Color4(Color.White); material.Power = 1f; device.SetStreamSource(0, vertexBuffer, 0, vertexSize); device.VertexDeclaration = vertexDeclaration; device.Indices = indexBuffer; device.Material = material; device.SetTexture(0, texture); var param = effect.GetParameter(null, "mWorldMatrixArray"); var boneWorldTransforms = bones.OrderedBones.OrderBy(x => x.Id).Select(x => x.CombinedTransformation).ToArray(); effect.SetValue(param, boneWorldTransforms); effect.SetValue(effect.GetParameter(null, "mViewProj"), Matrix.Identity);// Matrix.PerspectiveFovLH((float)Math.PI / 4, (float)device.Viewport.Width / device.Viewport.Height, 10, 10000000)); effect.SetValue(effect.GetParameter(null, "MaterialDiffuse"), material.Diffuse); effect.SetValue(effect.GetParameter(null, "MaterialAmbient"), material.Ambient); effect.Technique = effect.GetTechnique(0); var passes = effect.Begin(FX.DoNotSaveState); for (var i = 0; i < passes; i++) { effect.BeginPass(i); device.DrawIndexedPrimitives(PrimitiveType.TriangleList, 0, 0, skin.Vertices.Length, 0, skin.Indicies.Length / 3); effect.EndPass(); } effect.End(); } Again, I set diffuse and tex0 vertex shader outputs to zero, but my model still shows the full texture and lighting as if I hadn't changed the values from the vertex buffer. Changing the position of the model works, but nothing else. Why is this? Also, whatever I set in the bone transformation matrices doesn't seem to have an effect on my model. If I set every bone transformation to a zero matrix, the model still shows up as if nothing had happened, but changing the Pos field in shader output makes the model disappear. I don't understand why I'm getting this kind of behaviour. Thank you!

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