New Release: PETSTRIP for PET/CBM 3032 and 4032

[tokra]

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.

[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.

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

[tokra]

Cheers, it is actually 88x200 updating 11 characters instead of just 10 per line.

[groepaz]

This is really very cool. Imagine showing this to ppl back in 1980 :=)

[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

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.

[pixel]

Now how do I clean that keyboard?