Re: [hatari-devel] A few demos with issues in 1.6.2

[Nicolas Pomarède <npomarede@xxxxxxxxxxxx>]

On 23/07/2012 11:49, Anders Eriksson wrote:
> --------------------------------------------------
> 2. Digital World 3 / ICE
> http://files.dhs.nu/files_demo/ice_kool.zip
>
> a) some graphics garbage around lower border (second part)

Hello

problem because in the bottom part the demo changes video address in 
$ff8209 while the display is active. Hatari doesn't fully emulates this 
so far (on a real STE, it's a bad practice too, but in that case it 
"works" because the change happens when all pixels are black).


> --------------------------------------------------
> 3. Phantom / Arkham
> http://www.atarimania.com/demo-atari-st-phantom_22143.html
>
> a) endpart, screens jumps up/down.

The timings to remove top border are really tight, the switch to 60/50Hz 
sometimes happens 4-8 cycles to late.
This might be a problem in Hatari related to some exceptions timings, 
but I don't know where.
Note that the problem is less visible in STE mode, because on STE top 
border removal limit is 4 cycles later than on STF.

I think this demo might have been coded on STE and never tested on STF : 
during the  kind of "sine ribbon" part, you get some kind of blue colors 
in STF mode, and a "better" shade of purple in STE mode. I think the 
palette was designed for STE with 12 bits and they didn't notice it gave 
bad results with 9 bits in STF mode :)

So, no easy fix for these 2 for now, they go on the todo list.

Nicolas