Problem with Simple Directmedia Layer (SDL_Delay)

S

SpiralCorp

I'm having some trouble with SDL_Delay. I'm trying to limit framerate
for a
little tech-demo practice thing I'm doing. Now, this works perfectly:

==============
while (fps.stop() < ( 1000 / FPS ) ){ //fps.stop() being part of my
timer
//wait // class it returns the
enlapsed time
} //between start()
and stop().
==============

Of course, this uses up all the CPU time available and skips when
anything
else happens. None of which are acceptable. So I used this instead:

==============
time = 33 - fps.stop(); //Time being Uint32
if ( time > 0 ){
SDL_Delay( time );
}
==============

This is when it all breaks down. The delay has a very unpredictable
behaviour.
It starts working just fine and with no speed variations... then the
animation
just stops and none of the events respond. Clearly stuck in the delay
function.

So what gives? Am I doing anything wrong?

Heres the whole code from the modified version (SDL_Delay one)
http://pastebin.com/m3719631

Thanks
 
K

Kai-Uwe Bux

SpiralCorp said:
I'm having some trouble with SDL_Delay. I'm trying to limit framerate
for a
little tech-demo practice thing I'm doing. Now, this works perfectly:

==============
while (fps.stop() < ( 1000 / FPS ) ){ //fps.stop() being part of my
timer
//wait // class it returns the
enlapsed time
} //between start()
and stop().
==============

Of course, this uses up all the CPU time available and skips when
anything
else happens. None of which are acceptable. So I used this instead:

==============
time = 33 - fps.stop(); //Time being Uint32

UInt32 looks like an _unsigned_ type. Note that unsigned types cannot hold
negative values. If fps.stop() returns something greater than 33, the left
hand side is negative and will be converted to a (probably very large)
unsigned integer in the assignment.
if ( time > 0 ){

Note that the above condition is equivalent to time != 0 if time is
unsigned. Is that really what you want?

SDL_Delay( time );
}
==============

This is when it all breaks down. The delay has a very unpredictable
behaviour.
It starts working just fine and with no speed variations... then the
animation
just stops and none of the events respond. Clearly stuck in the delay
function.

So what gives? Am I doing anything wrong?

Heres the whole code from the modified version (SDL_Delay one)
http://pastebin.com/m3719631


Best

Kai-Uwe Bux
 

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