Re: [Tuxnes-devel] Smoother scrolling

[Mike M. <che...@ya...>]

I was chasing a simular problem, but I coulden't get any thing to work.  I don't think it's
correct to cahnge the usleep, as it's based on the NTSC standared.  I.E. 16666 = 1 frame and if
were n frames ahead 16666 * ( n - 1 ) is how long we wait.

My solution was to eliminate the extra gettimeof day call.  You only need one to get timing right.
 Here is how I normaly do video games...

Loop ()
  Read input  <-- this is done inline with nes code and will not be called every frame.
  Adjust position of objects, calculate score, ect  <-- this is all in nes code.
  Draw
  x = gettimeofday 
  sleep frametime * ( x - y - 1 )
  y = x <-- we now use another gettimeof day call for this
endloop

This is how tuxnes lookes...
set_renderer_basetime
Loop () { /* renderer.c */
  set_timeframe /* This is my y = x */
  call nes rom { /* These may happen in any order based on rom loaded */
     Optionaly read input
     Optionaly play sound
     Change memory /* This includes drawing something */
  }
  Draw contens of nes memory.
  set_frameskip
  resynchronize /* Notice time spent in resynchronize is not accounted for! */
}

Here is the last commit.
Mon Dec 8 16:46:33 2003 UTC (5 weeks, 6 days ago) by cheako
RCS file: /cvsroot/tuxnes/tuxnes/emu.c,v
retrieving revision 1.89
retrieving revision 1.90
diff -u -r1.89 -r1.90
--- tuxnes/tuxnes/emu.c	2003/12/05 23:05:37	1.89
+++ tuxnes/tuxnes/emu.c	2003/12/08 16:46:33	1.90
@@ -4,7 +4,7 @@
  * Please see the README and COPYING files for more information regarding
  * this project.
  *
- * $Id: emu.c,v 1.89 2003/12/05 23:05:37 cheako Exp $
+ * $Id: emu.c,v 1.90 2003/12/08 16:46:33 cheako Exp $
  *
  * Description: This file contains the main() function of the emulator.
  */
@@ -2116,7 +2116,7 @@
     }
 
   /* enter the Game Genie codes */
-  while (gamegenie != 0)
+  while (gamegenie > 0)
     {
       if ( gamegenie == 1 ) gamegenie = 0;
       if (verbose) fprintf (stderr, "------------------------\n");
@@ -2162,6 +2162,7 @@
             fprintf (stderr, "Game Genie: value at %04X = %02X\n", address,
                      MAPTABLE[address >> 12][address]);
         }
+      if ( gamegenie == 0 ) break;
        ggcode[--gamegenie] = '\0';
        for (; gamegenie >= 2; gamegenie--)
 	  if ( ggcode[gamegenie-1] == ',' ) break;



--- Ryan Jackson <pro...@ya...> wrote:
> I'm new to the list, but I've been following the project for quite some
> time now.  So please forgive me if I say something stupid ;-).
> 
> I've noticed that on my hardware (a rather unimpressive PII-350 with
> nVidia RIVA TNT video card) that tuxnes' scrolling seemed kindof choppy.
> I started looking around the code, and found the resynchronize()
> function.  By tweaking the value passed to usleep(), the scrolling
> became almost perfectly smooth.  The one side effect I've noticed is
> that sound gets out of sync a bit more often than before, but not by
> much.
> 
> I was considering writing a patch that would add a command-line option
> to decrease this delay by some amount (1 or 2 milliseconds seems to do
> it for me), but I was wondering if anyone might have a better solution.
> I'm not sure what unintended effects my hack might have.  Any ideas?
> 
> Also, has anything been committed to CVS in the last couple of months?
> There have been some postings to the list that indicate there has, but
> 'cvs update' doesn't download anything.  Maybe I'm just smoking
> something... ;-)
> 
> -- 
> Ryan Jackson
> pro...@ya...
> 
> 
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