Thread: good time control system

my game right now has a main loop like this:

Code:

	
PHP Code:
	


do
{
       //check input functions//
       //update player position//
       //update computer logic (moveX, moveY)//
       //update computer position (xPos+=moveX, etc.//
       
       //clear screen//
       //draw background//
       //draw player//
       //draw computer//
       //flip screen//
} while(!gameOver); 

Where in all that do i put in something to control speed? How can i do this? (I've never made a large arcade type game before, so I've never really faced this problem)

I don't know much about programming but I can tell you you can try to use the

Sleep(miliseconds);

function located in the <windows.h>. It will give you a delay in between your commands, and it's what I used for animation.

anybody ever done this?

If you are using the SDL look at SDL_AddTimer or you could
try something like

Code:

void Something::update()
{
       Uint32 time_now = SDL_GetTicks();
       double delta_time = (time_stamp - time_now) / 1000.0;
       time_stamp = time_now;

       x += xvel * delta_time;
       y += yvel * delta_time;
}

Calling SDL_Delay, I've found, usually makes the game too slugish.

ok so my speeds were real low (originally pixel by pixel so they were like 10) and I got the following suggestion:

xPos += (((SDL_GetTicks()-last_time)/1000.0)*xVel);

but b/c of my speeds being low it was real slow so instead of multipling each speed by about 200 (which i found gave me a desired speed) i did this:

xPos += (((SDL_GetTicks()-last_time)/1000.0)*xVel*200);

which i later simplified to this:

xPos += (((SDL_GetTicks()-last_time)/50.0)*xVel);

is this a decent solution?

If you have xvel=10 and the game is set in 800x600 it should take the main charecter a minute to move across the screen. But what actually happens is that SDL_GetTicks()-last_time)/1000.0)*xVel
is less than one and since the x and y coords are ints
the charecter ends up standing still.

i changed the x and y coords to doubles for this, but should it work then?

Try floats since SDL_GetTicks only is in milliseconds and you don't really need to much precision anyways.
Also see how fast the game goes between updates and
print out xvel * delta_time and so on. 10 pixels is pretty slow so try like 60 pixels per second.

I've got it running at good speed now, It ran the same on the P3 800MHz, the P2 233MHz, and another P3 that was a bit slower (400 i think, but i'm not sure).