Re: Prince of Persia
Posted: Sun Apr 28, 2024 8:33 pm
I still can't believe it! It never ceases to amaze me on what the Vic-20 can do.
Well Done!
Well Done!

The Commodore Vic 20 Forum
https://www.sleepingelephant.com/~sleeping/ipw-web/bulletin/bb/
https://www.sleepingelephant.com/~sleeping/ipw-web/bulletin/bb/viewtopic.php?t=10970
No problem! Based on the photo I posted of your game being played on my TV, do you foresee any significant visual elements necessary for gameplay being cut off? I can tell that one of the energy bars is missing, but the game still seems quite playable to me, regardless.
I guess I can do both. I will initialize it with the correct values depending whether it is PAL or NTSC (for NTSC, I'll use the values you mentioned in a previous post) but can also provide the option to center the screen by using cursor keys (that is already available, but only from the presentation screem, so will enable that also during the game).
Thanks!. Yes, I saw it. When he mentioned he was going to try Prince of Persia in the Atari 400 mini, I thought he might mention the VIC-20 version. And he did, and also showed a short video of itOrangeman96 wrote: ↑Mon Apr 29, 2024 9:23 pm You're famous now: the 8-Bit Guy mentions your work in his latest! -OGM
I didn't know you could adjust the screen position with the cursor keys already. You see, I found out about your game from the aforementioned 8-bit guy video and he also said that the game also only works in PAL. So, I got so excited about playing it that I downloaded it and immediately from here.Lechuck wrote: ↑Tue Apr 30, 2024 8:14 am I guess I can do both. I will initialize it with the correct values depending whether it is PAL or NTSC (for NTSC, I'll use the values you mentioned in a previous post) but can also provide the option to center the screen by using cursor keys (that is already available, but only from the presentation screem, so will enable that also during the game).
I'll upload a new version with that change next week.
Once again, well done! -OGMLechuck wrote: ↑Tue Apr 30, 2024 8:21 amThanks!. Yes, I saw it. When he mentioned he was going to try Prince of Persia in the Atari 400 mini, I thought he might mention the VIC-20 version. And he did, and also showed a short video of itOrangeman96 wrote: ↑Mon Apr 29, 2024 9:23 pm You're famous now: the 8-Bit Guy mentions your work in his latest! -OGM![]()
Cheers
Yes, I mentioned it in the Description, in the post where I uploaded the zip with the gameGhislain wrote: ↑Tue Apr 30, 2024 11:20 am I didn't know you could adjust the screen position with the cursor keys already. You see, I found out about your game from the aforementioned 8-bit guy video and he also said that the game also only works in PAL. So, I got so excited about playing it that I downloaded it and immediately from here.
I then proceeded to make the modification to get it centered on an NTSC screen.
So if you had mentioned the cursor key thing in another post or in documentation somewhere, I didn't read it.
My bad!
Thanks, Mike,Mike wrote: ↑Wed May 01, 2024 2:29 am The ROM table at $EDE4 can be used to obtain useful default values for XPOS and YPOS by applying constant offsets, regardless whether you have a PAL or NTSC VIC-20:
This saves you a complicated PAL/NTSC detect routine, and it is exactly the same method MINIGRAFIK uses to re-center the display window for the 160x192 pixel resolution.
- $EDE4 contains 12 for PAL and 5 for NTSC, when you substract 5, you get 7 for PAL and 0 for NTSC.
- $EDE5 contains 38 for PAL and 25 for NTSC, when you subtract 10, you get 28 for PAL and 15 for NTSC, the latter which should still be in order (Ghislain empirically obtained 13 instead).
You should be more specific in that, and give at least some information about your setup (real h/w vs. emulation, RAM size; on real h/w: brand of RAM expansion), at what point PoP diverts from the expected behaviour, and what is shown on screen instead.Barney wrote:No matter what I try, [...]