Path: chuka.playstation.co.uk!scea!greg_labrec@interactive.sony.com
From: Scott Cartier <dsyaroze@concentric.net>
Newsgroups: scea.yaroze.programming.2d_graphics
Subject: Re: Too many GsSortSprites?
Date: Sun, 03 Aug 1997 22:38:40 -0700
Organization: SCEA Net Yaroze News
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Scott reads Mario's suggestion and scratches his head.  It couldn't
be *that* could it?  Oh well he tries it anyway just to satisfy his
curiosity.

Wouldn't you know it worked?

I've been killing myself for a couple months on this problem and it
turns out to be such a simple solution.  I actually remember when I 
changed my code from the ordering below (which works) to the other
ordering (which didn't work all the time - but it worked enough of
the time for me to just grit my teeth and deal with it).  I though 
I was making it better since I was grouping all the double buffer 
routines together instead of breaking them up into two pieces (one 
at the beginning of the loop and one at the end).

Looking at it now I wonder how my incorrect code worked at all.  The
first time through my loop my GsSortClear and GsDrawOt were being
called without activeBuff containing a value.  Of *course* that's 
going to cause problems.

Muchas gracias Senor Perdue!  I'm so glad I'm not alone with this
Yaroze thing!

Scott


> >Hi all,
> >
> >I'm having a locking up problem that I've been tearing my hair to
> >figure out.  I've had this problem for some time and have run out
> >of ideas for debugging.  It seems rather simple.
> >
> >I have an array of sprites which represent my game objects.  Every
> >frame I loop through this array and use GsSortSprite to put them
> >on the screen.  Whenver this loop is greater than about 6 my
> >program locks up.  The only thing I could think of is that I'm
> >overloading the GPU with packets.  So I tried adding a DrawSync(0)
> >after each GsSortSprite call, but no luck.  Here's my basic flow:
> >
> >  initialize_sprites();
> >
> >  while(pad_state[PAD_SELECT] == 0) {
> >    move_sprites();
> >
> >    for (i = 0; i < num_sprites; i++)
> >      GsSortSprite(&sprt_array[i], &WorldOT[activeBuff], 2);
> >
> >    cnt = VSync(0);
> >    ResetGraph(1);    // hi-res mode
> >    GsSwapDispBuff();
> >
> >    GsSortClear(0, 0, 0, &WorldOT[activeBuff]);
> >
> >    GsDrawOt(&WorldOT[activeBuff]);
> >    activeBuff = GsGetActiveBuff();
> >    GsSetWorkBase((PACKET *)GpuPacketArea[activeBuff]);
> >    GsClearOt(0, 0, &WorldOT[activeBuff]);
> >
> >    compute_new_sprite_pos();
> >  }
> >
> >This is over simplified of course, but you get the idea.  Is there
> >anything obvious that I'm doing wrong?
> 
> Scott,
> 
> I'd try something more like this:
> 
>   initialize_sprites();
> 
>   while(pad_state[PAD_SELECT] == 0)
>     {
>     activeBuff = GsGetActiveBuff();
>     GsSetWorkBase((PACKET *)GpuPacketArea[activeBuff]);
>     GsClearOt(0, 0, &WorldOT[activeBuff]);
> 
>     compute_new_sprite_pos();
> 
>     move_sprites();
> 
>     for (i = 0; i < num_sprites; i++)
>       GsSortSprite(&sprt_array[i], &WorldOT[activeBuff], 2);
> 
>     DrawSync(0);
>     cnt = VSync(0);
> 
>     GsSwapDispBuff();
>     GsSortClear(0, 0, 0, &WorldOT[activeBuff]);
>     GsDrawOt(&WorldOT[activeBuff]);
>     }
> 
>   ResetGraph(1);    // hi-res mode
> 
> Mario