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synchronization of game cycles
Posted: Fri Jan 01, 2016 6:58 pm
by alko
I want to normalize FPS.
fact is that with the appearance of those or other particles also appearance lags.
Code: Select all
int dx;
int dy;
...
while(TRUE)
{
handleInput();
drawObjects();
drawParticles1();
drawParticles2();
SPR_update(sprites, 80);
VDP_waitVSync();
}
that is, depending on changes FPS must be change values dx dy (increments of the coordinates).
I tried as follows.
But anything sensible did not work.
Code: Select all
int TICKS_PER_SECOND;
int SKIP_TICKS;
int MAX_FRAMESKIP ;
u32 next_game_tick = getTick();
int loops;
...
int main(){
loops = 0;
MAX_FRAMESKIP = 10;
TICKS_PER_SECOND = 50;
SKIP_TICKS = 1000 / TICKS_PER_SECOND;
while(TRUE)
{
while( getTick() > next_game_tick && loops < MAX_FRAMESKIP)
{
handleInput();
drawObjects();
drawParticles1();
drawParticles2();
next_game_tick += SKIP_TICKS;
loops++;
}
SPR_update(sprites, 80);
VDP_waitVSync();
}
}
Re: synchronization of game cycles
Posted: Sat Jan 02, 2016 3:59 pm
by Stef
Use the V interrupt callback to calculate your base timing, be sure to not miss any interrupt by disabling them too long and that should do it !
To setup the V interrupt callback just use SYS_setVIntCallback(..) method.
Re: synchronization of game cycles
Posted: Sat Jan 02, 2016 8:00 pm
by alko
I did not understand...
Do you offer like that?
Code: Select all
int TICKS_PER_SECOND;
int SKIP_TICKS;
int MAX_FRAMESKIP ;
u32 CB;
int loops;
...
int main()
{
loops = 0;
MAX_FRAMESKIP = 10;
TICKS_PER_SECOND = 50;
SKIP_TICKS = 1000 / TICKS_PER_SECOND;
SYS_setVIntCallback(CB);
while(TRUE)
{
while( CB > next_game_tick && loops < MAX_FRAMESKIP)
{
SYS_setVIntCallback(CB);
handleInput();
drawObjects();
drawParticles1();
drawParticles2();
next_game_tick += SKIP_TICKS;
loops++;
}
SPR_update(sprites, 80);
VDP_waitVSync();
}
}
Thus, the game freezes.
Re: synchronization of game cycles
Posted: Sat Jan 02, 2016 8:59 pm
by Stef
CB is a callback, by callback a mean a method which is called at a specific event.
Code: Select all
// vint method forward declaration
void vint();
...
int main()
{
...
SYS_setVIntCallback(vint);
...
while(TRUE)
{
...
}
}
void vint()
{
tick++;
}
As vint() method will be call automatically at each vertical interrupt you are sure your tick variable will be incremented 50/60 times per second.
Then you just need to base your game speed on 'tick'.
Re: synchronization of game cycles
Posted: Sun Jan 03, 2016 10:18 am
by alko
?
Code: Select all
int TICKS_PER_SECOND;
int SKIP_TICKS;
int MAX_FRAMESKIP ;
u32 next_game_tick;
u32 tick ;
int loops;
void vint();
...
int main()
{
loops = 0;
MAX_FRAMESKIP = 10;
TICKS_PER_SECOND = 50;
SKIP_TICKS = 1000 / TICKS_PER_SECOND;
SYS_setVIntCallback(vint);
next_game_tick=tick;
...
while(TRUE)
{
while( tick > next_game_tick && loops < MAX_FRAMESKIP)
{
SYS_setVIntCallback(vint);
.... //update game
next_game_tick += SKIP_TICKS;
loops++;
}
SPR_update(sprites, 80);
}
}
void vint()
{
tick++;
}
still not working.
Re: synchronization of game cycles
Posted: Sun Jan 03, 2016 1:13 pm
by Stef
You only need to call VDP_setVIntCallback(..) once at initialization.
Also i don't really understand your game synch logic but what about just doing this :
Code: Select all
int main()
{
SYS_setVIntCallback(vint);
gameFrame = 0;
...
while(TRUE)
{
// wait for at least one game frame
while(gameFrame == 0);
while(gameFrame > 0)
{
// update game
...
gameFrame--;
}
SPR_update(sprites, 80);
}
}
void vint()
{
gameFrame++;
}
Re: synchronization of game cycles
Posted: Sun Jan 03, 2016 9:07 pm
by alko
pace of the game has become normal.
But at the beginning some time: game (coordinates of the objects) is updated, and sprites is don't updated.
Re: synchronization of game cycles
Posted: Sat Jan 09, 2016 10:32 am
by alko
Code: Select all
while(TRUE)
{
handleInput();
if(star_game_f==TRUE)
{
u32 current = getTick();
u32 elapsed = current - previous;
previous = current;
lag += elapsed;
while (lag >= VAR)
{
upgate_gaym();
lag -=VAR;
}
SPR_update(sprites, 80);
}
Now, if the VAR is equal to 10, the gameplay is flawless, but first couple of seconds the sprites are not updated while the coordinates of their updated with furious speed.
If VAR is made equal to 50, then all updated immediately, but the picture is a slideshow.
Re: synchronization of game cycles
Posted: Sun Jan 17, 2016 8:27 am
by alko
how to reset the timer, which receives time of getTick () ?
Re: synchronization of game cycles
Posted: Sun Jan 17, 2016 8:40 pm
by Stef
You can't reset timer from getTick() which is the "system" timer but you can use
and
Code: Select all
u32 getTimer(u16 numTimer, u16 restart);
for that (see
https://github.com/Stephane-D/SGDK/blob ... nc/timer.h )