20 October 2021, 15:56 | #1 |
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Join Date: Sep 2021
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Age: 54
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Weird effect when scrolling
I'm trying scrolling effects for the first time but getting a strange ripple / flicker. You can see it here
[ Show youtube player ] In each program loop, I use screen copy to move the whole screen down by 1 pixel then paste what was the bottom line of pixels back at the top, but as you can see it's not a smooth effect. I've tried using Def Scroll but it's exactly the same. I am using double buffer. Thanks Setup - WinUAE 4.4.0, Windows 10, AMOS Pro V2 |
20 October 2021, 17:07 | #2 |
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Join Date: Apr 2018
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Do you have a waitvbl?
I have a vague memory of a plugin for amos which gave far faster scrolling blits for this function. |
20 October 2021, 18:25 | #3 |
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Yeah I've got a wait vbl
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20 October 2021, 20:14 | #4 |
Phone Homer
Join Date: Jun 2006
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Probably too bigger area for screen copy, screen copy was a terrible way to scroll a screen use hardware scrolling with the Screen Offset command.
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21 October 2021, 10:59 | #5 |
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Screen offset works perfectly, thanks!
[ Show youtube player ] |
21 October 2021, 17:36 | #6 |
Phone Homer
Join Date: Jun 2006
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Looks like your vertical scrolling tiles.
Idrougge kindly shared some code to endlessly hardware scroll vertically with tiles in Amos, it might be useful http://eab.abime.net/showthread.php?t=80646 Last edited by Retro1234; 22 October 2021 at 08:43. |
22 October 2021, 08:56 | #7 |
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Join Date: Sep 2021
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Thanks for the link, I'll take a look
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22 October 2021, 11:27 | #8 |
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Amos not including a built-in solution to scrolling was a disaster.
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22 October 2021, 17:49 | #9 |
Phone Homer
Join Date: Jun 2006
Location: 5150
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it does Screen Offset ?
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22 October 2021, 18:29 | #10 |
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It has no (tile) scrolling engine though. So it's a fiasco to figure out the best way to do it. If you go about it wrong it's hopelessly slow (but the manual gives no indication of the right/most optimised route). I still could not tell you the fastest way to do it in AMOS. You just end up with games using the max screen size and hacks. |
22 October 2021, 18:34 | #11 |
Phone Homer
Join Date: Jun 2006
Location: 5150
Posts: 5,782
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Same as every Amiga language but what still baffles me is examples back in the day, like with Tome telling people to use screen copy for scrolling, we know now this wrong but why they endorsed this? anyone have any idea?
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