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"The Graphic Demo" in NTSC?

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#1 monzamess OFFLINE  



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Posted Mon Nov 13, 2017 8:38 PM

Back in the day I had a copy of Peter Sabath's "The Graphic Demo" that ran fine on my NTSC 130XE. Over 25 years later, I have a different NTSC 130XE and I've downloaded 10 (possibly) different copies of "The Graphic Demo" to try on my SIO2SD, and they all show the loading/RAMDISK screen, then the opening starts and it gets stuck playing a constant tone and with the screen rolling/flickering.  I guess this is a PAL/NTSC issue, maybe not (could be unknown issue with my computer), but I bet a working copy is out there somewhere.... help?





#2 Rybags ONLINE  



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Posted Mon Nov 13, 2017 11:50 PM

The one you linked does that in emulation as well.   But if you start in Pal then change later it seems OK.


Chances are the beginning part isn't NTSC friendly - if you had a working version then maybe someone fixed it.

A quick look... it's probably hanging because in that part the VBlank runs too long, in PAL you've got about 5000 cycles more until the active screen starts, which is cause for many compatibility issues.

Edited by Rybags, Tue Nov 14, 2017 12:19 AM.

#3 _The Doctor__ OFFLINE  

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Posted Tue Nov 14, 2017 10:08 AM

On real machines... there was a fixed or working version at one time. Perhaps someone will patch it again.

This is one more reason why we should be keeping and notating the versions. Assuming the many repositories in far away lands will do this is proving false.

Often they get translated to the language of said repository then toss the original language or even versions that work under different broadcast formats..... my fave is then being told it can't be put back to it's original format or language as has happened from time to time

Edited by _The Doctor__, Tue Nov 14, 2017 10:22 AM.

#4 monzamess OFFLINE  



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Posted Tue Nov 14, 2017 1:46 PM

Appreciate the thoughts, although fixing it is way over my head. Pretty sure I found it on a BBS back then so maybe there is a BBS file archive (or a real live BBS) with the NTSC-fixed version. Google's not helping much this time!

#5 CharlieChaplin OFFLINE  


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Posted Tue Nov 14, 2017 3:41 PM



since I am living in "La-La-PAL-Land" (Germany), I rarely test if a program is NTSC compatible. Some years ago I uploaded two versions of P.Sabath`s "Graphic and Sound" demos. The older version (by Dendrit-Software = P.Sabath 1985) works with 64k RAM and was originally made for the german magazine Computer Kontakt, the newer version (by P.Sabath 1986) works with 64k and 128k RAM and was made for Compyshop.  (Not sure if any of these demo versions also work with less than 64k RAM...)



(post #26)  or alternatively:




Give these a try and if they also do not work with NTSC, maybe the single fileversions do ? Afaik, all parts of this (these) demo(s) are available as single fileversions, some e.g. here:



(same link as above, post #29)


If the fileversions also do not work with NTSC, then I don`t have any more ideas...





#6 monzamess OFFLINE  



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Posted Tue Nov 14, 2017 8:52 PM

This is the version I had, and it works fine on my NTSC 130XE.  See "Awesome Demo #1" on this page:  http://pokeysoft.no/...tari/a8demo.htm

#7 Xuel OFFLINE  



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Posted Tue Nov 14, 2017 11:15 PM

I took a shot at NTSC-fixing the original demo:


Attached File  graphic-demo-ntsc-fix.atr   90.02KB   30 downloads


  • Shorten the kernel on the top of the screen so it doesn't eat up so much CPU time
  • Move the computation of rainbow colors into the kernel itself instead of as a separate loop
  • Clean up the bottom border so that the color change is stable (only visible on extended PAL height)

Messy patch code:


Attached File  graphic-demo-ntsc-fix.asm   4.91KB   26 downloads

#8 monzamess OFFLINE  



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Posted Wed Nov 15, 2017 6:34 PM

That works for me, thanks!





#9 ndary OFFLINE  



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Posted Fri Nov 17, 2017 11:46 PM

here is a file verison of the PAL demo

Attached Files

#10 CharlieChaplin OFFLINE  


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Posted Sat Nov 18, 2017 1:26 PM

here is a file verison of the PAL demo


But it is still PAL-only... needs to be patched for NTSC. (And "Kluge-Soft" should be changed back to P. Sabath!) Xuel or anyone else, can you also patch this fileversion to work correct with NTSC ?

Edited by CharlieChaplin, Sat Nov 18, 2017 1:26 PM.

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