The Sinclair QL Forum

Posted: **Mon Oct 25, 2021 9:06 am**

bwinkel67 wrote:Why was the coordinate system changed for NTSC?

I guess because pixels have a different shape/ratio and thus circles weren't circles with the PAL settings. I personally think it's a mistake, but well.

Posted: **Mon Oct 25, 2021 10:57 am**

mk79 wrote:
bwinkel67 wrote:Why was the coordinate system changed for NTSC?
I guess because pixels have a different shape/ratio and thus circles weren't circles with the PAL settings. I personally think it's a mistake, but well.

But they don't have different apsect ratio. In Monitor mode, both NTSC and PAL give you 512x256 so it's one-to-one. It doesn't make sense to me why the coordinate system is different.

Posted: **Mon Oct 25, 2021 11:24 am**

bwinkel67 wrote:But they don't have different apsect ratio. In Monitor mode, both NTSC and PAL give you 512x256 so it's one-to-one. It doesn't make sense to me why the coordinate system is different.

It's not like the US-QLs were a well-thought-out venture. In Minerva (there is no NTSC version of Minerva, but the code was prepared for it) it's

Code: Select all

* Push screen aspect ratio onto stack
gw_asp
; if ntsc
;       move.l  #$6623b79c,-(a1) 2/(4/3*575/512*51.2/51.95) * 1.173
;       move.w  #$801,-(a1)
; else
*        move.l  #$56b851ec,-(a1) 2 / ( (4/3) * (575/512) * (51.2/51.95) )
*        move.w  #$801,-(a1)      (acually rounded(?) to 1.355)

And in mode 8 this value is simply divided by two, so it does simply have a different aspect ratio in general. Again, not that I approve of this, it's just the way it is.

Posted: **Mon Oct 25, 2021 12:19 pm**

I fixed the scaling issues so now it works properly in NTSC TV and Monitor mode as well in PAL TV and Monitor mode.

QBQLSoundsv5.zip: (22.43 KiB) Downloaded 148 times

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