Just use a second sprite attribute table and switch to
this table when your ready with changing the sprite
coordinates. Beaware that the color table is linked to
the sprite attribute table in screen 4 and above.
> -----Original Message-----
> From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf
> Of Patriek
> Lesparre
> Sent: Saturday, April 22, 2000 4:42 PM
> To: [EMAIL PROTECTED]
> Subject: Re: virtual retrace?
>
>
>
> > > So i was wondering, is there a way to see when to move the sprites
> > > (maybe by use of vrt retr.)? I assume there is because
> most games i
> > > played don't have this icky movement :-)
> >
> >You can read bit6 of VDP status register 2 to find vertical retrace:
> >VDP(-2) and &H40
> >
> >I forgot whether zero or non-zero means the vertical retrace
> is active.
>
> It's SET during retrace.
>
> >But I'm not sure BASIC is fast enough to react to vertical retrace...
>
> The problem is, as soon as the retrace starts the normal
> interrupt kicks
> in. If the BASIC interrupt routine (RST 38h) is fast enough
> to be completed
> within the retrace (or blanking) period, you have a chance
> you can still do
> stuff.
>
> On the other hand, maybe it's better to use a ON INTERVAL
> command. I'm not
> sure how it works, but if it's interrupt driven it might be
> faster than
> checking S#2 bit 6. Besides, I don't even know you CAN read
> S#2 in BASIC
> since the interrupt routine always expects S#0!
>
> Patriek
>
>
> ****
> MSX Mailinglist. To unsubscribe, send an email to [EMAIL PROTECTED]
> and put "unsubscribe msx [EMAIL PROTECTED]" (without the quotes) in
> the body (not the subject) of the message.
> Problems? contact [EMAIL PROTECTED]
> More information on MSX can be found in the following places:
> The MSX faq: http://www.faq.msxnet.org/
> The MSX newsgroup: comp.sys.msx
> The MSX IRC channel: #MSX on Undernet
> ****
****
MSX Mailinglist. To unsubscribe, send an email to [EMAIL PROTECTED]
and put "unsubscribe msx [EMAIL PROTECTED]" (without the quotes) in
the body (not the subject) of the message.
Problems? contact [EMAIL PROTECTED]
More information on MSX can be found in the following places:
The MSX faq: http://www.faq.msxnet.org/
The MSX newsgroup: comp.sys.msx
The MSX IRC channel: #MSX on Undernet
****
