NAME

STRUCTURE DEFINITION

typedef struct{
  Uint8 scancode;
  SDLKey sym;
  SDLMod mod;
  Uint16 unicode;
} SDL_keysym;

STRUCTURE DATA

scancode

Hardware specific scancode

sym

SDL virtual keysym

mod

Current key modifiers

unicode

Translated character

DESCRIPTION

The scancode field should generally be left alone, it is the hardware dependent scancode returned by the keyboard. The sym field is extremely useful. It is the SDL-defined value of the key (see SDL Key Syms. This field is very useful when you are checking for certain key presses, like so:

.
.
while(SDL_PollEvent(&event)){
  switch(event.type){
    case SDL_KEYDOWN:
      if(event.key.keysym.sym==SDLK_LEFT)
        move_left();
      break;
    .
    .
    .
  }
}
.
.

mod stores the current state of the keyboard modifiers as explained in SDL_GetModState. The unicode is only used when UNICODE translation is enabled with SDL_EnableUNICODE. If unicode is non-zero then this a the UNICODE character corresponding to the keypress. If the high 9 bits of the character are 0, then this maps to the equivalent ASCII character:

char ch;
if ( (keysym.unicode & 0xFF80) == 0 ) {
  ch = keysym.unicode & 0x7F;
}
else {
  printf("An International Character.
");
}

UNICODE translation does have a slight overhead so don't enable it unless its needed.

SEE ALSO