Hawk Uli indicated that color cycling, a la Atari 8 bit indirect color registers, isn't directly possible.
I did some really simply, brute force color cycling here >> `https://youtu.be/oAwZ6gl8RKE
Something like the two color Amiga bouncing ball should be trivial swapping between background layers and blitting, shouldn't it? From looking through the manual it should be. I've not yet played with multiple backgrounds, but I have done some stuff with blitting relatively large images and moving them about very quickly. The test in the following video moves a 320x240 PNG image (on a 640x480 screen) of the original Xbox logo nearly 18,000 pixel increments in 10 seconds (later to find out that I was running not full bore), so the horsepower is there to do some interesting stuff >> `https://www.youtube.com/watch?v=TN25QmnTxQ4 . I'm not sure how of the memory map that the graphics engine uses. It'd be neat to try drawing the differently colored components off-screen to RAM and brute force the cycling via blits.
Even on SCREEN 16 and loading 800x600 JPGs (120KB each, reduced from 16MP images, at 85% JPG quality. From this folder >> `https://drive.google.com/drive/folders/1WmbS29yyqVDfNWpTa41D7v0LidvmCvFO ) from the uSD card, we can get as fast or faster animations than a Genesis or SNES. Certainly it can be done from RAM and at an order of magnitude - or more - faster than pulling it across the uSD card. In the off chance that you might need some mountain images and such, those images are mine and you are free to use them as you wish. I have lots of pretty good images that I will pull over to that BASIC Engine assets folder soon, in full unadulterated quality, just in case anyone in the community can use something.
Do you know if there is a fixed address or an offset address for the start of video memory? VPEEK, VPOKE, and VREG are original BASIC Engine only, but would be awesome if implemented on the NG.
Sorry for rambling 🙂
Edit: I've brought a couple of my capture devices home. My apologies for the quality and sound on the videos above.