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beloxx89

OpenGL Opengl fonts 2d

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beloxx89    122
Hello, Im trying to include text in my 2d opengl game. Im using SDL for input so I was thinking, I could listen for all keys like that switch(event.type){ case SDL_KEYDOWN: switch(event.key.keysym.sym){ case SDLK_LEFT: ... case SDLK_RIGHT: ... case SDLK_UP: ... case SDLK_DOWN: ... case SDLK_A: ... case SDLK_B: ... case SDLK_C: ... case SDLK_D: ... and then draw each character from an opengl texture. Is that efficent or is there some other way? Thanks

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Ezbez    1164
Is your problem with reading in bits? If so, there's the "sym" member variable of SDL_keysym. You can use it like so:

//"event" is a keyboard event
Uint16 character = event.key.keysym.unicode;

It has the character associated with the key. If there's shift or caps on, it's properly capitalized. For things that aren't character keys (eg: F12, return), it will give you a non-existant character (usually drawn as a square or blank space).

Edit: I should point you over to the SDL reference which makes note of a couple things, such as you must call SDL_EnableUNICODE before this will work.

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I think he means adding some kind of text-input box, or perhaps a chatting system, to his game.

@beloxx89: Your way would work, but a potentially* better way would be to make use of the 'unicode' field of the keysym.

*It'd involve less copy+pasted code of all 26 cases for each letter, but might be take a bit of trouble to get it working.

It'd look more like this:

std::string myString;

switch(event.type){
case SDL_KEYDOWN:{
switch(event.key.keysym.sym){
case SDL_BACKSPACE:
myString.pop_back();
break;
default:{
if(event.key.keysym.unicode != 0){ //It's a charactor for us to read.
if ((event.key.keysym.unicode & 0xFF80) == 0) { //Taken from the keysym page, should ensure it's a ASCII charactor.
myString.append((keysym.unicode & 0x7F));
}
}
} break;
}
}
}


You'd have to mess around with it a bit to get it working properly. (Hmm, I just googled "event.key.keysym.unicode" to find you a article or tutorial to help, and apparently Lazyfoo has one)

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