A10001986 wrote:Dynamic HAM is using HAM (320) and changing the palette on every raster line. (How they want to avoid fringing is not clear to me, because HAM works horizontally, and its limitations of color-changes from one pixel to the next are limited horizontally, too - but having 16 distinct colors on each line probably at least helps.)
Dynamic HiRes is Hires (640) with its 16 colors, and also changing that 16 colors' palette on every raster line. (I assume the system will be pretty unresponsive in that mode, given the bitplane and copper DMA are on full throttle here.)
This is what I don’t quite understand. They make it seem like Dynamic HAM and Dynamic HiRes are related but the trick of changing the palette on each scanline in hi-res mode aka Dynamic HiRes seems to be quite different to how regular HAM mode works.
I’m not a big fan of the fringing artefacts of HAM (don’t get me wrong HAM was revolutionary at the time), but for this purpose I’m trying to steer clear of anything that is ‘HAM-like’.
intric8, I believe SHAM is different again, but in what way exactly I’m not sure!
So a bit of a google dive brought me to this:
https://www.ppa.pl/forum/scena/38042/dy ... -amiga-500
(unless you speak Polish you’ll need to hit translate).
Apparently this fellow is developing a proper Dynamic HiRes converter. Awesome!!
He lays out a typical workflow for conversion:
1. We make our masterpiece in any ordinary PC graphics program using full RGB24.
2. Convert the image to dynamic Hires
3. We manually correct artefacts which unfortunately are unavoidable.
In other words, as I suspected, a simple conversion process is probably not going to yield a satisfactory result. The artist needs an understanding of how her artwork will translate to this mode and pre and post process touch-ups (on a pixel level) are inevitable.
Not every artwork or photograph is going to be right for conversion. In fact it is probably best to produce artwork with this mode in mind from the beginning.
As the developer explains, he has not released his tool publicly because the conversion process is complex and will be different depending on the image.
Anyway, it’s great to know that this sort of development is happening. The more you think about these dynamic modes the more you think about the (un-tapped) possibilities. Perhaps there’s a way to cycle the palette on each screen refresh to push the perceived colour palette well past the Amiga’s 4096 ceiling. While I’m walking the dog in the morning this is the sort of thing I’m thinking about.
I’m currently reading Jimmy Maher’s superb book The Future Was Here (I’m super late to this one - should have picked up a copy sooner) which does a fantastic job of explaining the magic of the Amiga’s hardware in terms a non-expert like me can understand. Highly recommended.