Orbitals, a PSI Res program
Orbitals, a PSI Res program
This is a new listing from Popular Computing Weekly, 11/82. The program original printed hi-res output to the ZX Printer. I've converted it to display the output using the Pseudo Hi-Res video driver, therefore, it will run on a standard 16K ZX81. I've also included the original printer version as well.
Regards;
Greg
Regards;
Greg
- Attachments
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- Orbitals.zip
- Programs and info
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Re: Orbitals, a PSI Res program
PSI-res. Haha I love it!
Re: Orbitals, a PSI Res program
Hi Greg
The program looks great, especially with my hi-res font!
I tried the program using EightyOne and found that the picture was not being displayed properly:
I then tried it on a real ZX81 fitted with a Chroma interface and it did not like the picture either.
I think old TVs using an aerial connection were a lot more tolerant of slightly off timing.
Looking at the hi-res routine, it appears that the delay before rendering the top line of the display area is too short. A stable picture can be achieved by changing LD B,$12 to LD B,$14 at $5BD9, although then the picture will not be centred but shifted to the left. A better solution is to use timings matching those found in Forty Niner and Rocket Man as follows:
Using these alternate timings, EightyOne shows the top line of the display offset a pixel or two but I believe this may just be an issue with the emulator as I do not see this offset using real hardware.
It is great to see these old type in programs in action. Have you submitted all the ones you have typed in for archiving at the The Type Fantastic website?
The program looks great, especially with my hi-res font!
I tried the program using EightyOne and found that the picture was not being displayed properly:
I then tried it on a real ZX81 fitted with a Chroma interface and it did not like the picture either.
I think old TVs using an aerial connection were a lot more tolerant of slightly off timing.
Looking at the hi-res routine, it appears that the delay before rendering the top line of the display area is too short. A stable picture can be achieved by changing LD B,$12 to LD B,$14 at $5BD9, although then the picture will not be centred but shifted to the left. A better solution is to use timings matching those found in Forty Niner and Rocket Man as follows:
Code: Select all
@HRESGEN
DI
LD HL,$C061
LD DE,$0021
LD C,$FE
LD B,$16
@SYNC3
It is great to see these old type in programs in action. Have you submitted all the ones you have typed in for archiving at the The Type Fantastic website?
Re: Orbitals, a PSI Res program
I'm surprised that it didn't work in EO as the screen shots I posted are from EO. I can understand problems on real hardware, mainly due to the PAL/NTSC differences. I attempted to compensate for this by checking MARGINS before staring the hi-res display and adjusting the delay.
Thanks for making your font available for download, it's very nice. I have another font I extracted from a Hi-Res typewriter program, it's a bit larger using 7 line and 1 blank, but is a bit more ragged than yours.
Regards;
Greg
Thanks for making your font available for download, it's very nice. I have another font I extracted from a Hi-Res typewriter program, it's a bit larger using 7 line and 1 blank, but is a bit more ragged than yours.
Regards;
Greg
Re: Orbitals, a PSI Res program
Thanks. The font dates from 1987 and comes from a hi-res utility I created to extend basic with new user friendly commands for manipulating a hi-res display (drawing, printing, circles, scrolling, etc). It is nice to see the font used to good effect all these years later. I hadn't actually realised it was my font to begin with, although I did think it looked very familiar. Then I saw my name and chuckled...GCHarder wrote:Thanks for making your font available for download, it's very nice.
The problem appears to be the timing of the left hand border of the first scan line of the main display area, and not due to the number of top/bottom border lines which does vary between 50Hz and 60Hz machines.GCHarder wrote:I can understand problems on real hardware, mainly due to the PAL/NTSC differences.
So far the only way I can get EightyOne to display the picture undistorted is by lowering the Horizontal Hold setting in the TV Emulation dialog (by default it is in the centre position). Could you check your TV Emulation settings. It would be very nice to be able to explain the difference.GCHarder wrote:I'm surprised that it didn't work in EO as the screen shots I posted are from EO
Re: Orbitals, a PSI Res program
Here's a screenshot of my settings for EO and results for some other emulators. Forty Niner runs OK in EO and sx81, ZEsarUX still doesn't like the delay value, at least not on my set-up.
Regards;
Greg
Regards;
Greg
Re: Orbitals, a PSI Res program
This is the first program I've found in quite a while which doesn't run correctly on my emulator Spud81. I'll have to take a look at the code and see if I can get it to run. Perhaps I'll add horizontal and vertical setting to help.
Re: Orbitals, a PSI Res program
Ok, so a quick bit of coding later and now Spud81 can run Orbitals correctly (assuming you tweak the horizontal hold setting!)
You can find Spud81 here - http://bit.ly/MYuLBX
Enjoy!!
You can find Spud81 here - http://bit.ly/MYuLBX
Enjoy!!