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Old 04 August 2017, 21:43   #21
Toni Wilen
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If DDFSTRT == DDFSTOP: stop never happens, you get max overscan.

There is always at least two "bitplane blocks" because DDFSTOP means "one more block to go before end".
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Old 05 August 2017, 03:19   #22
NorthWay
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Quote:
Originally Posted by Toni Wilen View Post
If DDFSTRT == DDFSTOP: stop never happens, you get max overscan.
Erm... no. I did say AGA though. See my poor mobile snap. (I haven't fixed the modulos to make it look right as I was only looking for the effect. EDIT: modulo 24 corrects it)

Quote:
Originally Posted by Toni Wilen View Post
There is always at least two "bitplane blocks" because DDFSTOP means "one more block to go before end".
I guess I can live with that as I more or less intended to allow for scrolling anyway.

But how did you set up the copper for the split testing then?
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ID:	54024  

Last edited by NorthWay; 05 August 2017 at 03:43. Reason: EDIT
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Old 05 August 2017, 11:51   #23
Toni Wilen
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I used ECS, lores, single bitplanes (to make it easier to position copper moves when testing)

$8001,$fffe
DDFSTRT=$40
DDFSTOP=$70
$8071,$fffe
DDFSTRT=$7a ($78 is too small)
DDFSTOP=$c8
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Old 05 August 2017, 14:31   #24
aros-sg
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horizontal split: what about dual playfield and changing playfield priority mid screen?
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Old 05 August 2017, 16:18   #25
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Excuse the OT, NorthWay, but is that a multisync screen you've got there?
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Old 05 August 2017, 21:14   #26
NorthWay
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Originally Posted by idrougge View Post
Excuse the OT, NorthWay, but is that a multisync screen you've got there?
An old Nokia 447M I blagged from work. 20+ years? Connected to an AMON scandoubler.
I.e. yes. But not 15KHz. AFAIK.

(I'll do some more testing when my sleeping pattern isn't so fucked up and I have the energy to think clear. Tired but can't get proper sleep...)
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Old 06 August 2017, 20:14   #27
NorthWay
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Welcome to Weirdness, population >=1.

From 38 to D8 with STRT=STOP I see fetches from left overscan to STOP. I.e. at B8/B8 I need modulo -8, D8/D8 -16. D8/F8 same as D8/D8.
With 18/18 I get _full_ overscan (so including right side) and need -16 modulo.
(Still showing a 320 pixel wide picture.)
Checking when the values are looked at with $38/$58 seems to give (subtract 8 to get wait for copper position):
STRT changed (to $78) earlier than $XX79 will combine with the old (to give the full overscaneffect ). Setting it back to $38 has no effect!!! (Wrong position I set it?)
STOP changed (to $9a?) earlier than $XX59 will always replace the old one.

I get the same result as Toni; there needs to be one idle fetch cycle if not then the logic will join together the display settings.
Is it possible to find any way of reseting the logic behaviour? Change fetchmode? Toggle DMA? Write bitplane data registers? Bueller?

Last edited by NorthWay; 06 August 2017 at 22:47.
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Old 07 August 2017, 01:57   #28
NorthWay
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Sometimes a picture says more than 1K words.
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Old 07 August 2017, 10:42   #29
ovale
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Wow!
Success?
How small you managed to get the gap?
Code?
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Old 07 August 2017, 19:45   #30
NorthWay
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No gap. I had more or less surrendered. I don't really know what I did to make it work. Split -16 / +24 modulo IIRC.

Source and exe attached.

Wait, this is a new effect so I get to name it, right?
In that case, please meet "Tech-Tech-Tech". (Isn't that an appropriate name? Any sideways shift, repeating.)

WinUAE 3.5.0 does not replicate the way it looks on my 4000.
Also, I am getting a white colour instead of black that I don't understand. (Down left side and at the bottom. Not in WinUAE.) EDIT: Bug in PicCon - it says 69 colours, but wont save or edit more than 64. Some colour data is $DEADF00D... If I force conversion to 8 planes it saves everything.

The source has lots of stuff from something else I did at one point in time so you can strip out a whole lot.
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Old 09 August 2017, 01:30   #31
NorthWay
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Did anyone test the executable or make their own?
Does it work for you, do you see the same effect as me?
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Old 09 August 2017, 12:22   #32
robinsonb5
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Quote:
Originally Posted by NorthWay View Post
Did anyone test the executable or make their own?
I'll definitely take a look when time allows - nice work!
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Old 09 August 2017, 12:31   #33
Toni Wilen
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AGA probably allows it in higher fetchmodes if DMA is considered stopped after first 8 DMA slots of "bitplane block" after DDFSTOP. (not full 16 or 32 slots, depending on FMODE)

This would make it possible to restart DMA during following idle slots = no gap. (This is my guess, nothing tested yet)

EDIT: I am now 99.9% sure that this explains it. There must be some extra logic in AGA that stops the DMA "early", probably because without it active DMA would wrap around to next line which most likely would cause side-effects even when DMA does not do any fetches.

EDIT2: Emulation code updated to support this situation and display appears to be identical to your screenshot (except that one color but I think it is uninitialized palette entry)

Last edited by Toni Wilen; 09 August 2017 at 21:30.
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Old 04 August 2018, 10:22   #34
dissident
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Quote:
Originally Posted by NorthWay View Post
No gap. I had more or less surrendered. I don't really know what I did to make it work. Split -16 / +24 modulo IIRC.

Source and exe attached.

Wait, this is a new effect so I get to name it, right?
In that case, please meet "Tech-Tech-Tech". (Isn't that an appropriate name? Any sideways shift, repeating.)

WinUAE 3.5.0 does not replicate the way it looks on my 4000.
Also, I am getting a white colour instead of black that I don't understand. (Down left side and at the bottom. Not in WinUAE.) EDIT: Bug in PicCon - it says 69 colours, but wont save or edit more than 64. Some colour data is $DEADF00D... If I force conversion to 8 planes it saves everything.

The source has lots of stuff from something else I did at one point in time so you can strip out a whole lot.
Definitely a very cool trick. Thanks for sharing your code, NorthWay. I will play a little bit with this feature on my A1200.
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Old 20 October 2018, 06:17   #35
NorthWay
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Quote:
Originally Posted by dissident View Post
Definitely a very cool trick. Thanks for sharing your code, NorthWay. I will play a little bit with this feature on my A1200.
If anyone has looked at this then I'm sorry for the borked logic that hoisted the right hand split one line above the left. I finally got my head on the right way and saw how I had swapped modulos.
I also can't find the graphics files I originally used - I think they are on an IDE drive (I'm using a lovely silent SATA SSD on my cybscsi) so the copperlist is still missing some colours. I think I have the original files at work, and if not I'll see if I can get the IDE disk to talk to something or other (I have an original X-Surf with IDE but I'm not 100% sure if it is possible to use the cable the wrong way around, and where the driver is. Sits in my 3000 which has the lid off.)
I'll pack up everything needed to make it assemble (own includes and all) when I find the files.

Funny how you can't move onto the next thing until you are satisfied with the old one...
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