Behalf Of Geoff Winkless
Sent: 02 February 2012 12:01
To: sam-users@nvg.ntnu.no
Subject: Re: Single pixel hardware scroll?
On 2 February 2012 11:02, Simon Owen wrote:
>
> On 2 Feb 2012, at 10:24, Geoff Winkless wrote:
>> If you're thinking of playing with stuff like that
Having checked, the full complement of z80 lines are on the expansion
connector so it wouldn't be a problem to figure out when the z80 is
accessing memory. That being said, if the ULA fetches aren't there
then there would appear to be a problem.
Maybe a smarter plan would be something that plugs i
>> a) tell the difference between a normal address request and an ASIC request
Is the z80's MREQ line available to peripherals? I forget whether
that's active during refresh cycles but it would probably give the
game away. Alternatively, the WAIT line probably gives something of
the game away.
I'm sure I'm just repeating what you already know but...
They're accurate for (most) aperture grille CRTs but completely
inaccurate for shadow mask CRTs. Sony had aperture grilles patented
for its Trinitron screens right up until the late 90s so they're a
tiny minority, especially of televisions c
On 2 Feb 2012, at 11:50, Geoff Winkless wrote:
> If you could just change that 15-bit offset to start at XhXl using
The emulation side doesn't keep it as a pure offset, but from what I remember
it should still be relatively easy. There might be some funky side-effects for
attributes in mode 1,
On 2 February 2012 11:02, Simon Owen wrote:
>
> On 2 Feb 2012, at 10:24, Geoff Winkless wrote:
>> If you're thinking of playing with stuff like that in SimCoupé, how
>> about adding in a screen start address OUT mod? I'd love to see what
>> could have been done with just a small change to the ASIC
On 2 Feb 2012, at 10:24, Geoff Winkless wrote:
> how about adding in a screen start address OUT mod?
Would that be possible with a real SAM peripheral? Can the value on the bus be
changed to redirect the display read? Or is it possible to modify the value
read instead? Perhaps something that
On 2 Feb 2012, at 10:43, Thomas Harte wrote:
> emulator authors tend to be quite parochial and superstitious about this
> stuff for some reason, hence e.g. the mostly invented black scan lines a lot
> of them like to insert.
I find a partial scanline effect helps soften a harsh pixelated image,
On 2 Feb 2012, at 10:24, Geoff Winkless wrote:
> If you're thinking of playing with stuff like that in SimCoupé, how
> about adding in a screen start address OUT mod? I'd love to see what
> could have been done with just a small change to the ASIC design :)
I was drawn by the possibility of there
The weird thing then is that the article claims the effect can be triggered by
border changes in the invisible part of the screen. Though I guess the screen
he had probably just had a large amount of the tube hidden from the eye. The
idea that border colour changes can somehow insert an extra 64
On 1 February 2012 20:42, Simon Owen wrote:
> On 01/02/2012 20:07, Thomas Harte wrote:
>> I notice that whatever effect it thinks it is relying on doesn't work
>> in Sim Coupe.
>
> It's certainly nothing that's implemented at the moment, but if it's
> shown to be a real effect (like border pixels)
On 01/02/2012 20:07, Thomas Harte wrote:
> I notice that whatever effect it thinks it is relying on doesn't work
> in Sim Coupe.
It's certainly nothing that's implemented at the moment, but if it's
shown to be a real effect (like border pixels), it should go in. Though
it does feel like it could
ength about how a single pixel hardware scroll would
buy you two frames to update the display rather than one if you wanted
a scrolling area. It's also weirdly specific to a particular monitor
in one place, and I notice that whatever effect it thinks it is
relying on doesn't work in Sim Cou
ng information, preferring to
> talk at great length about how a single pixel hardware scroll would
> buy you two frames to update the display rather than one if you wanted
> a scrolling area. It's also weirdly specific to a particular monitor
> in one place, and I notice that whatev
black and white can affect the
position of the pixel area within the television frame by a row. Sadly
it doesn't bother to explain what aspect of the hardware it thinks is
responsible or to provide any real timing information, preferring to
talk at great length about how a single pixel hardware s
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