key detection with SDL library

This is a discussion on key detection with SDL library within the C++ Programming forums, part of the General Programming Boards category; hello I am making a chat program which (obviously) needs to detect the ascii of the key pressed. Unfortunately I ...

  1. #1
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    key detection with SDL library

    hello

    I am making a chat program which (obviously) needs to detect the ascii of the key pressed.

    Unfortunately I can get only the ascii of the "real" key pressed.
    I don't know how to explain that, so here's an example:

    when the user presses just <a>, SDL gives me the code 97 (which is the correct ascii code for "a")
    if the user presses <SHIFT + a>, SDL again gives me 303 (the R-SHIFT code used by SDL) and again 97.

    ok, I simply might recognize when the user presses shift, which is not a hard deal but...
    if I have to check for non-alphabetical keys?
    here is the complication, explained with a comparation:

    italian user presses <9> : ascii code is 57
    english user presses <9> : ascii code is 57

    italian user presses <SHIFT + 9> : character is ")", ascii code is 41
    english user presses <SHIFT + 9> : character is "(", ascii code is 40

    I've already tried to implement a function which detects the input, but there happen some conflicts with SDL.
    also my knowledge with low-level C coding is not good.

    Which way should I start from? thanks

    edit: I'd also be glad to make it portable

    edit solved: ok, nevermind, I've just found the perfect solution:
    http://listas.apesol.org/pipermail/s...ne/044058.html
    Last edited by carlorfeo; 02-07-2008 at 07:40 AM. Reason: solved

  2. #2
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    This is the code (found somewhere in the net) from which I've extracted a function to be used by my program.
    Even studying it, I still don't understand the great part of these lines...
    By the way I guess this program deals with the terminal specifically, which is not what I really need, am I wrong?

    Code:
    #include <termios.h>
    #include <iostream>
    
    int main(void)
    {
    	int count;
    	int jndex;
    	int result;
    	int virgin;
    
    	char echoed_data;
    	char in_buffer[80];
    
    	struct termios tp1;
    	struct termios tp2;
    
    	virgin=1;
    	echoed_data='X';
    
    	printf("Type a space character to exit.\n");
    
    	tcgetattr(0,&tp1);
    
    	tp2=tp1;
    
    	tp2.c_iflag&=~ICRNL;
    	tp2.c_lflag&=~ICANON;
    	tp2.c_lflag&=~ECHO;
    	tp2.c_cc[VMIN ]=1;
    	tp2.c_cc[VTIME]=0;
    	tp2.c_cc[VINTR]=0xFF;
    	tp2.c_cc[VSUSP]=0xFF;
    	tp2.c_cc[VQUIT]=0xFF;
    
    	tcsetattr(0,TCSANOW,&tp2);
    
    	do {
    		in_buffer[0]=0;
    
    		count=read(0,in_buffer,1);
    
    		if(virgin)
    		{
    			virgin=0;
    			tp2.c_cc[VMIN]=0;
    			tcsetattr(0,TCSANOW,&tp2);
    		}
    
    		if(count>0)
    			echoed_data=in_buffer[0];
    
    		printf("&#37;d: ", echoed_data);
    		printf("%d\n", 256 + echoed_data);
    
    		fflush(stdout);
    
    	} while(echoed_data!=0x20);
    
    	printf("\n");
    
    	tcsetattr(0,TCSANOW,&tp1);
    
    	return 0;
    
    }
    Last edited by carlorfeo; 02-07-2008 at 06:55 AM.

  3. #3
    Kernel hacker
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    You probably want to use SDL events, and in particular SDL KeyboardEvent

    Search the web for those two, and you will find more info.

    --
    Mats
    Compilers can produce warnings - make the compiler programmers happy: Use them!
    Please don't PM me for help - and no, I don't do help over instant messengers.

  4. #4
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    Thank you matsp
    That's it. I didn't search enough

    Quote Originally Posted by carlorfeo
    edit solved: ok, nevermind, I've just found the perfect solution:
    http://listas.apesol.org/pipermail/s...ne/044058.html

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