void SetState(int nNewState)
   {
      nState = nNewState;

      switch(nState)
      {
      case STATE_START:   Execute = Startup; break;
      case STATE_TITLE:   Execute = TitleScreen; break;
      case STATE_MMENU:   Execute = MainMenu; break;
      case STATE_RUNGM:   Execute = RunGame; break;

      // And just in case something goes wrong:
      default:            Execute = Abort; break;
      }
   }

Quote:

Original post by Fruny So would have been pointing out that you cannot manipulate bound pointers-to-members (particularly, you can't store them).

void a_function()
{
 cout<<"BAR!";
}

int main()
{
 void (*funcpointer)(void) = a_function;
 (*funcpointer)();
}

class some_class
{
public:
 void a_function()
 {
  cout<<"BAR!";
 }
};

int main()
{
 some_class MyObj;
 void (some_class::*funcpointer)(void) = &some_class::a_function;
 //Just calling (*funcpointer)() would not work
 (MyObj.*funcpointer)();

}

if(HIGH_RES)
         Draw = DrawHiRes;
      else
         Draw = DrawLowRes;

if(HIGH_RES)
         Draw = &CTurret::DrawHiRes;
      else
         Draw = &CTurret::DrawLowRes;

Quote:

Original post by graveyard filla although i think there would be absolutely no performance increase (i mean cmon, its an if statement man), i DO see how this makes things more readable, and more elegant.

Quote:

Original post by graveyard filla Quote: Original post by Fruny So would have been pointing out that you cannot manipulate bound pointers-to-members (particularly, you can't store them). could you explain this more? i dont understand what your talking about =)

Quote:

Original post by Madster Actually the big increase in speed would be from entering the switch *only* when changing states, and skipping right to the chosen function in the main loop As opposed to going trough the switch every single time in the loop. while i see the performance increase, the benefit i see for gamedev is little, as these rendering switches usually are executed small number of times per frame anyway (not always tho). What i'm interested on is that tiny comment about flags handling. For example, if i have a zillion flags, how do i avoid checking each one with an 'if' statement? example: renderer flags: -render edges -render console -render shadows -render FPS -etc etc etc disregarding shader logic, in the renderer i'd just ask for each flag. besides making each combination of flags a different member function and switching between them (a zillion flags make up for a bajillion combinations!!) how could this kind of thing be sped up using function pointers? I always knew how to handle them... i just couldnt find any use for them

Quote:

Original post by Ready4Dis Another great thing about function pointers is this: I have a GUI I wrote, and I use function pointers attached to the command buttons. This way, when a button is clicked, whatever function I want called gets called. So, if I have a Quit button, I just create it with the Quit function as a parameter and it's good to go :).

class CTurret {
public: 
void  DrawHiRes(float fAngle);
void  DrawLowRes(float fAngle);

// original Draw slightly modified //
void (CTurret::*pDraw)(float);

// the addition //
inline void Draw(float fAngle) { (*this.*pDraw)(fAngle); }

   void setup() {
      if(HIGH_RES)
         pDraw = DrawHiRes;
      else
         pDraw = DrawLowRes;
   }
};

  CTurret *Turret;
  ...
  Turret->Draw(angle); 

Quote:

Original post by VThornheart The big thing about if statements is that they require the processor pipeline to attempt a "branch prediction" in order to process further instructions. You see, the processor can begin computing machine instructions several steps above the current one, as long as it knows absolutely what's coming up next (among other things).

Quote:

Original post by griffenjam As for not using a typedef...well...typedefs are for commies.

Quote:

For the longest time I didn't even think about functions pointers until I was looking at a state machine one day and wished that instead of having a switchboard of if statements that executed single functions based on the state of the program, the class would just automatically execute the function appropriate for the current state. I realized that I could accomplish this with function pointers. I will create a small example class with various member function and a state changing function that will switch the current execute function. This is a good example of how to use function pointers to control the flow of a program and eliminating the if statements that you hit every time you call that function

if (state == OVER)
   gameOver();
else if (state == DEAD)
   restartLevel();
else if (state == GOAL)
   loadNextLevel();

if (state == OVER)
   gameState = gameOver();
else if (state == DEAD)
   gameState = restartLevel();
else if (state == GOAL)
   gameState = loadNextLevel();