Page 1 of 1

New Release: PETSTRIP for PET/CBM 3032 and 4032

Posted: Sun Sep 10, 2023 3:05 am
by tokra
screenshot.png
Download: https://www.pouet.net/prod.php?which=95051

YouTube: https://www.youtube.com/watch?v=RxBvDF5CpSo

Commodore PET entry for the Wild competition @Nordlicht 2023.

This game uses a newly developed graphics-mode called PECBM11 which provides a resolution of 88x200 pseudo-hires pixels. PECBM11 is based on PECBM (80x200 pixels) by Genesis Project's "A Bright Shining Star"-demo.

It updates the video-RAM char-pointers on each rasterline and works on machines with or without CRTC-chip. This is done by syncing to the VBLANK-bit first. Only the timing is slightly different for machines with CRTC-chip. The CRTC is then set to a display mode very similar to the original PET 2001.

If you want to use VICE make sure you use a version larger than 3.7.1-r44426 or just download a recent build from:

https://github.com/VICE-Team/svn-mirror/releases

It will not work in VICE 3.7 or 3.7.1!

This was successfully tested on a 4032 and on a MINI PET 40/80.

If you use a MINI PET make sure to set the video output dip switches to 9" PET. Only in that mode it produces the same 260 rasterlines as the original machine.

I would welcome reports from useres with 3032 PET/CBMs. On older 2001s with 32K it will likely produce a strange picture. This is due to all the updates to the video-RAM.

Re: New Release: PETSTRIP for PET/CBM 3032 and 4032

Posted: Sun Sep 10, 2023 4:12 am
by Mike
Cool!

I knew of that project at least since Revision this year, it is really nice to see the game realized with graphics, in the good tradition of VICSTRIP. :mrgreen:

The extremely aspected graphics mode (80x200) naturally seems to lead to an overt choice of ph*ll*c landmarks for PET's trip. ;)

Greetings,

Michael

Re: New Release: PETSTRIP for PET/CBM 3032 and 4032

Posted: Sun Sep 10, 2023 4:24 am
by tokra
Cheers, it is actually 88x200 updating 11 characters instead of just 10 per line.

Re: New Release: PETSTRIP for PET/CBM 3032 and 4032

Posted: Sun Sep 10, 2023 11:22 am
by groepaz
This is really very cool. Imagine showing this to ppl back in 1980 :=)

Re: New Release: PETSTRIP for PET/CBM 3032 and 4032

Posted: Sun Sep 10, 2023 4:08 pm
by tokra
Thanks, surprisingly the general technique for this was already done in March 1980 and is even a testprog in the VICE-repo:

https://sourceforge.net/p/vice-emu/code ... ET/hi-res/

You can read more about that in the original magazine on archive.org:

https://archive.org/details/Cursor_Issu ... ew=theater

Page 44 is where the HI-RES-program is explained. It talks about a maximum of 9 character-wide graphics and GP's demo last year did 10 chars wide graphics. So I just had to do 11 to not just look like a copycat :mrgreen:

A rasterline on the PET has 64 cycles, so 10 LDA/STA-pairs of 6 cycles for each char are kind of the natural choice. But if you distribute the updates just right, 11 char wide is doable.

I also wanted BASIC-interoperability for the Poker-part, but of the 260 rasterlines nearly 210 are used for the graphics-mode alone and the KERNAL needs some in the interrupt-routine as well. So basically I have something like a 0.1 Mhz-machine running BASIC 2.0 in the end.

Re: New Release: PETSTRIP for PET/CBM 3032 and 4032

Posted: Tue Sep 12, 2023 1:43 pm
by pixel
Now how do I clean that keyboard?