Question

I’m writing a game and I’m wound up in needing a console for simple text input; filenames and simple values.

Using SDL, my console looks the following at it’s simplest:

class   Console { public:   typedef std::list<String> InputList;    enum  Result   {     NOTHING = 0,     ENTERED,     ESCAPED   };    static const String&  GetInput()  { return input; }    static Result Query(SDLKey lastKey)   {     if(lastResult == ENTERED || lastResult == ESCAPED)     {       input.clear();     }      switch (lastKey)     {     case    SDLK_a:     case    SDLK_b:     case    SDLK_c:     case    SDLK_d:     case    SDLK_e:     case    SDLK_f:     case    SDLK_g:     case    SDLK_h:     case    SDLK_i:     case    SDLK_j:     case    SDLK_k:     case    SDLK_l:     case    SDLK_m:     case    SDLK_n:     case    SDLK_o:     case    SDLK_p:     case    SDLK_q:     case    SDLK_r:     case    SDLK_s:     case    SDLK_t:     case    SDLK_u:     case    SDLK_v:     case    SDLK_w:     case    SDLK_x:     case    SDLK_y:     case    SDLK_z:     case    SDLK_0:     case    SDLK_1:     case    SDLK_2:     case    SDLK_3:     case    SDLK_4:     case    SDLK_5:     case    SDLK_6:     case    SDLK_7:     case    SDLK_8:     case    SDLK_9:     case    SDLK_SLASH:     case    SDLK_BACKSLASH:     case    SDLK_PERIOD:     case    SDLK_COMMA:     case    SDLK_SPACE:     case    SDLK_UNDERSCORE:     case    SDLK_MINUS:         input += static_cast<char> (lastKey);         lastResult = NOTHING;         break;     case    SDLK_RETURN:         lastResult = ENTERED;         break;     case    SDLK_ESCAPE:         lastResult = ESCAPED;         break;     }     return lastResult;   }  protected:   static Result lastResult;   static String input; }; 

This would be called from the application’s main event loop, if the console is active and the last event was a keypress, then the result of the input is processed at a state where it’s necessary.

Of course, it looks incredibly awkward… What’s a better way to implement a simple console that can be easily rendered in my game’s window? (Not going anywhere near to highly unportable solutions like having to reroute std::cout or writing code to bring up a UNIX console etc.)

Answer 1

One suggestion I would offer is to use if statements instead of a switch in this case:

if(lastKey == SDLK_RETURN)     lastResult = ENTERED; else if(lastKey == SDLK_ESCAPE)     lastResult = ESCAPED; else if(lastKey >= SDLK_SPACE && lastKey <= SDLK_z) {     input += static_cast<char> (lastKey);     lastResult = NOTHING; } 

I took some liberties and included some characters that you didn’t have in your code above, such as the ampersand, quotes, parentheses, brackets, etc. If you don’t want those keys, you can add a few more if statements to break it down a bit more.

This assumes that the enum for the keys doesn’t change a lot. If it does change a lot you may be better off with what you had.