>At 08:12 AM 05/29/99 +0200, you wrote:
>
>>I'd prefer the 1st method (if it actually works) since I don't like the
>>idea of changing the adjust register overriding user's preset and leading
>>to a non centered screen on some monitors.
>
>Overriding user's presets also happens using the first method. For example,
>my monitor is aligned such that no borders at all are visible in 60Hz mode.
>That's why I never noticed NOP's overscan trick until someone else told me
>it was there.
An MSX display field is not meant (at hardware level) to be aligned such
that no borders at all are visible. It covers 98% of the horizontal scan
area and about 90% of the vertical scan area at 60Hz in 212 line mode. Your
monitor settings are just a personal choice which I recommend since you
also compensate the MSX weird aspect ratio ("egg-like circles").
The 1st method does not interfere with user's presets since you'll actually
be starting your display sooner and ending it later in a compensate way, so
the picture should be centered even if you have no borders.
The MSX 212 vertical height is actually a display MONSTRUOSITY. It should
have been a 256 x 192 screen ***with 1:1 pixel aspect ratio***, or better
320 x 224. The 20 additional lines somewhat compensate for the narrower
viewport, but also they sould have been 224, to round up (in character
terms) and cover the entire display area.
>>Mmm... it seems many MSX users are not much familiar with those hardware
>>tricks like overscan and sprite recycling. That would explain those
>>sprite-free trends.
>
>Sprite recycling is known to rather a lot of people. The problem with it is
>that you can only boost the total number of sprites on a screen, not the
>number of sprites on one line.
Neither an Amiga could boost the number of sprites per line, but vertical
recycling is powerful enough to yield impressive games/demos.
>Shouldn't the second line interrupt be between 192 and 212?
>Sound more logical to me: the VDP passes 192 and checks for 212 to end the
>screen. But before 212 is reached, you change end of screen to 192, which
>the VDP already passed.
It's indeed more logical. Still have to test it.
>But I wonder if it's just a coincidence that NOP used a repeating pattern
>as the background of their overscanned title screen. Maybe there is some
>nasty sideeffect to the overscan trick that you have to compensate for.
This method should have no side effects. It seems NOP used the 2nd, which
is more simple to guess but less powerful and it's obvious it has that
nasty side effect since you're actually moving down the same image to be
redisplayed.
>> MSX has not been used to its full potential yet.
>
>So, prove that and impress us with a FANTASTIC demo!
>(I love demo's!)
I'll rather impress you with a FANTASTIC GAME.
Kiss you lot.
--
Madonna Mark Two
"Martin Galway means to me what Elvis meant to Sigue Sigue Sputnik"
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