Parallax Distorter 2

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lotek_style
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Re: Parallax Distorter 2

Postby lotek_style » Thu Sep 20, 2018 8:48 am

Simply because we have no extra platform for STE... we have to tag it that way on Demozoo.
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Re: Parallax Distorter 2

Postby troed » Thu Sep 20, 2018 10:00 am

(yeah if that had been plain ST I would've given up demo coding ;))

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Re: Parallax Distorter 2

Postby slingshot » Tue Aug 20, 2019 10:23 am

Exuse me, but may I ask on what hw/emulator this screenshot made?

https://media.demozoo.org/screens/o/80/ ... 169612.png

It has black lines on the right side in every 16(?)pixels.

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Re: Parallax Distorter 2

Postby sigge » Tue Aug 20, 2019 12:05 pm

slingshot wrote:Exuse me, but may I ask on what hw/emulator this screenshot made?

https://media.demozoo.org/screens/o/80/ ... 169612.png

It has black lines on the right side in every 16(?)pixels.


Not sure about which emulator, but I think this is from an older version of the code. I had a couple of issues that I discussed earlier in the thread. If I remember correctly, one was with regards to "resetting the buffer" (screen address) at a bad place, and another where the screen start address was set incorrectly at the top of the screen. The reset of the buffer address only touched the middle byte of the screen address, so the offset in the low byte was preserved. The black lines are caused by displaying the end of the buffer, which was never filled with any font data (or even background playfield data).

I think the version on github has these issues fixed.

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Re: Parallax Distorter 2

Postby slingshot » Tue Aug 20, 2019 2:39 pm

sigge wrote:
Not sure about which emulator, but I think this is from an older version of the code. I had a couple of issues that I discussed earlier in the thread. If I remember correctly, one was with regards to "resetting the buffer" (screen address) at a bad place, and another where the screen start address was set incorrectly at the top of the screen. The reset of the buffer address only touched the middle byte of the screen address, so the offset in the low byte was preserved. The black lines are caused by displaying the end of the buffer, which was never filled with any font data (or even background playfield data).

I think the version on github has these issues fixed.


Secretly hoped that happens on the real HW, since the STe shifter code I wrote also displays similar black lines, however if it's due to bad video address, then it's not the shifter, but the GLUE/MMU.
But if it's a bad video address at the end of the line, how it's possible that it has the correct pixel data before the black spike? Or just look like it's correct, but not.

Upd.: seems the demozoo version is an older one, which works in Hatari, but not on real HW. I've downloaded from your github repo, it's perfect!

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Re: Parallax Distorter 2

Postby Gunstick » Sun Jan 05, 2020 11:35 pm

Hi

I feel quite honored of this remix. All the wonders what opensource code can bring.
I also created an STf vertical distorter, which uses hardscrolling to map vertical scrollers horizontally.
It is the always hidden screen you can find in the Oh Crikey demo and in the Snork demo.
I use a 2 bit bender.
https://www.youtube.com/watch?v=iJ_zpE7F4xE

I wonder if a diagnonally scrolling fullscreen is possible :-)
I saw it done with a repeating pattern. But with non repeating graphics?

Gunstick/ULM

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Re: Parallax Distorter 2

Postby Cyprian » Mon Jan 06, 2020 12:37 pm

"Ooh Crikey..." was the first serious demo I had and I was really impressed with it.
Gunstick, is it your screen? If yes congrats. I never found out how to enter it.
Can you tell a bit about details, technic ect?
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Re: Parallax Distorter 2

Postby Gunstick » Mon Jan 06, 2020 11:05 pm

A long time ago (i.e. in 1992) a friend told me to make the parallal distorter 90 degrees rotated. And I was like "htat's impossible" and the friend looked at me very seriously "you and impossible? lol!".
So I got to work.
I designed my first vertical disting scroller for that.
The rest is quite simple, just have the hardcroller move sideways. Same technique, it takes 4 screens to wrap around so you have a wide font but a smooth waveform.
Seems CPU time or memory was more strict as I did not use a sample tune but some madmax with digidrums.
The snork version uses another font which has a glass magnification effect. That's done by simply haveing the vertical stripes twice as large inside the letters. Also it has a raster which throws sometimes a rainbow onto the letters. That's nicely timed with the digidrums of the music so that when there is no digidrums the free time can be used to show the raster.

Maybe I should put it on github as I did with paradist with several versions to show the history of the creation of the screen.

Georges


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