Path: chuka.playstation.co.uk!news
From: "Peter Armstrong" <hanno@btinternet.com>
Newsgroups: scee.yaroze.freetalk.english
Subject: Re: Main Game Loop Technique
Date: Sun, 14 Jul 2002 20:13:43 +0100
Organization: PlayStation Net Yaroze (SCEE)
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Message-ID: <agsiuk$d9k29@www.netyaroze-europe.com>
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I've used pointers to functions for that sort of thing. I'd have an array of
function addresses and use the return value from the function call as the
array index.

As an example:

// functions to call
int   (*functions[5])(void)  = {NULL, TitleScrn, NewGame,
PlayerSelect,GameOptions};
.
.
.
.
void CallFunction(void)
{
  int  index  = 1;                   // init index
  int   (*FuncCall)(void);

  while(index)
  {
     FuncCall = functions[index];   // get function address

     index = FuncCall();   // call  function
  }
}

This method may well be less efficient than switch/case statements, I just
prefer to keep the in-function code compact, plus since I started using
function pointers I can't seem to stop. ;)

Peter

"Rikki Prince" <rprince@blueyonder.co.uk> wrote in message
news:agrf9f$d9k24@www.netyaroze-europe.com...
> Before I would do the following:
> main loop {
> Prepare screen drawing stuff
> if(TITLE_SCREEN) {
>     GsSort Title Screen stuff
> }
> elseif(GAME_SCREEN) {
>     GsSort Game stuff
> }
> etc
>
> if(ONE_PLAYER) {
>     Proccess for 1 player
> }
> elseif(TWO_PLAYER) {
>     Process for 2 player
> }
> etc
>
> } end of loop
>
> However, I'm wondering whether it's better to get rid of these checks
> every loop by checking what screen it is first, then going into a
> special loop for that screen, and doing similar for the number of
> players. Do those checks cause much of a performance hit - is it worth
> worrying about? Or is it better to keep the amount of code down (due
> to the 2MB limit), rather than duplicating it? I suppose I could use
> pointers to functions, so the main loop would be the same code, but
> somewhere else changes which function is pointed to, which does the
> specific proccessing. Could this be a good method?
>
> Cheers,
> Rikki
>
>