English Amiga Board - View Single Post - Horizontal Scrolling with 4x Fetch and all sprites

roondar · 04 December 2018, 22:53

I've been mucking about with AGA scrolling & sprites with 4x fetch but so far haven't managed something useful. Mainly due to the alignment restrictions of the bitplanes.

So far, my best result for 256 pixels wide @ 4x fetch + scrolling is basically the standard X position of the screen + 64 pixels. It may be possible to make this into a DDFSTRT at $34 (using the same trick to do so as would be used on the A500), but that would not change much.

I originally thought you might be able to do much better, but I forgot the bitplanes need to be aligned to 64 bits at all times in 4x fetch mode

04 December 2018, 22:53	#2
roondar Registered User Join Date: Jul 2015 Location: The Netherlands Posts: 3,423	I've been mucking about with AGA scrolling & sprites with 4x fetch but so far haven't managed something useful. Mainly due to the alignment restrictions of the bitplanes. So far, my best result for 256 pixels wide @ 4x fetch + scrolling is basically the standard X position of the screen + 64 pixels. It may be possible to make this into a DDFSTRT at $34 (using the same trick to do so as would be used on the A500), but that would not change much. I originally thought you might be able to do much better, but I forgot the bitplanes need to be aligned to 64 bits at all times in 4x fetch mode