Posted By
IstvanV
on 2007-11-11
14:38:46
|  Re: Drean Commodore 16 details -- finally...
The different clock division is still not a major issue, at least as far as the effects on speed and sound pitch are concerned, since it is handled in one place. The display effects are more interesting, since the NTSC bit should change the color encoding (i.e. +/- 33 degrees phase shift, different burst phase, and phase alternation), but not the dot clock and sampling of pixels. Anyway, it is more or less straightforward, just requires changing the already quite messy display code in many places.
While I do not emulate different amounts of horizontal color blur even for PAL vs. NTSC (I have never actually seen the NTSC picture anyway), it would be basically just adding a third GL fragment shader for the PAL-N mode, and changing the color blur as needed (it is essentially a 4x2 FIR filter for PAL, and a 4x1 one for NTSC; the sample positions can be fractional).
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