Saving sprite 5+6 on x64 Fetch with scrolling

mcgeezer · 04 March 2020, 22:11

Hi all,

I'm coding on AGA and tinkering with trying to save the 3rd pair of hardware sprites while scrolling in FMODE 3 (x64).

I'm just wondering if anyone of the more experienced coders knows if it's possible to save sprites 5+6 from being chopped when you want to use this mode with scrolling?

In the video below I'm changing the data fetch start to $2c which does save the sprite pair but it kills the scrolling a little, I'm wondering rather than spending a long while trying to get the scroll working, I thought i'd just ask if it's even possible.

[ Show youtube player ]

Geezer

hooverphonique · 04 March 2020, 22:37

wasn't there a trick described here recently about shuffling the scrolling values around to fix the scrolling when using bodged ddfstart?

mcgeezer · 06 March 2020, 21:32

I figured this out by the way.

It did involve shifting the screen to the right slightly but very much do-able.

Geezer

buzzybee · 22 March 2020, 17:43

You might also try to set position data (sprxpos and sprxctl) with copper instead of letting DMA do this. In certain fetch-cases this should enable you to rescue one of the sprites, which otherwise would not get a proper display.

I also did a lot of experimenting with copper-based writes to sprxdat, but this lead almost nowhere on AGAs fetch 2x and 4x modes.

04 March 2020, 22:11	#1
mcgeezer Registered User Join Date: Oct 2017 Location: Sunderland, England Posts: 2,702	Saving sprite 5+6 on x64 Fetch with scrolling Hi all, I'm coding on AGA and tinkering with trying to save the 3rd pair of hardware sprites while scrolling in FMODE 3 (x64). I'm just wondering if anyone of the more experienced coders knows if it's possible to save sprites 5+6 from being chopped when you want to use this mode with scrolling? In the video below I'm changing the data fetch start to $2c which does save the sprite pair but it kills the scrolling a little, I'm wondering rather than spending a long while trying to get the scroll working, I thought i'd just ask if it's even possible. [ Show youtube player ] Geezer

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04 March 2020, 22:37	#2
hooverphonique ex. demoscener "Bigmama" Join Date: Jun 2012 Location: Fyn / Denmark Posts: 1,624	wasn't there a trick described here recently about shuffling the scrolling values around to fix the scrolling when using bodged ddfstart?

06 March 2020, 21:32	#3
mcgeezer Registered User Join Date: Oct 2017 Location: Sunderland, England Posts: 2,702	I figured this out by the way. It did involve shifting the screen to the right slightly but very much do-able. Geezer

22 March 2020, 17:43	#4
buzzybee Registered User Join Date: Oct 2015 Location: Landsberg / Germany Posts: 526	You might also try to set position data (sprxpos and sprxctl) with copper instead of letting DMA do this. In certain fetch-cases this should enable you to rescue one of the sprites, which otherwise would not get a proper display. I also did a lot of experimenting with copper-based writes to sprxdat, but this lead almost nowhere on AGAs fetch 2x and 4x modes.

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