Re: [hatari-devel] PhotoChrome v6.2-pre

[Nicolas Pomarède <npomarede@xxxxxxxxxxxx>]

Le 16/10/2015 16:20, Troed Sångberg a écrit :
> Let me know if your pixel counting is different from calculating what
> _should_ be shown according to the state machine I've documented :P
>
> IIRC, the full line width should be 420 pixels _if_
>
> 1) The Shifter output doesn't start early due to words already preloaded and
> 2) Regular BLANK is what terminates the line
>
> (The HI/LO stabilizer at cycle 444 cuts the RGB output 6 cycles/pixels
> earlier than BLANK would)

The code in Hatari for this STE line does this :
 - each line is 224 bytes

 - Hatari has no idea of how many pixels are really available per line, 
it assumes each bytes is displayed (which is not the case on real HW, 
but is not noticeable in STF mode when you set screen width to 416 pixels).

 - on the left border, we have 20 extra bytes to display. But the 1st 4 
bytes (8 pixels) are not shown (hatari fill them with color 0, which 
explains why we see colors changing in the 8 leftmost pixels). Here we 
should have a special "blank" color that always stays black, but this 
doesn't exist for now. So in the end, left border has 32 extra pixels to 
use.

 - on the right border, we display whatever pixels the user chooses in 
the config. As a line is 224 bytes, this means 448 pixels and a max of 
96 pixels in right border. A real STE will turn DE off before and will 
not display 96 pixels, it will display only 64 or 68 pixels (to get a 
total width of 416-420 pixels). So here again, Hatari should be improved 
to really stop displaying pixel and put some "blank/black" color instead.

As those STE overscan lines are a little shorter than the standard 230 
bytes STF lines, the solution for now to get a nicer image is to set 
Hatari to 400 pixel width instead of 416 in the UI.

Nicolas



> /Troed
>
> On Fri, Oct 16, 2015 at 3:40 PM, Nicolas Pomarède
> <npomarede@xxxxxxxxxxxx <mailto:npomarede@xxxxxxxxxxxx>> wrote:
>
>
>     I have an old CRT monitor that I need to plug one day to check this.
>     It has some buttons to center/move screen horizontally/vertically,
>     which is useful to see pixels at the limits. So if I move screen to
>     left, I don't see the 1st left pixels, but I see all the pixels to
>     the right and I can see blank signal too. This way it's possible to
>     see where the display really stops on ST.
>
>      From what I see when connecting STF/STE to LCD TV, the TV upscales
>     the SCART image to be 1920x1080 and trim/alter some pixels doing so,
>     which is not handy to precisely check pixel one by one.
>
>
>     Nicolas