Re: Single pixel hardware scroll?

2012-02-02 Thread Geoff Winkless
On 1 February 2012 20:42, Simon Owen simon.o...@simcoupe.org 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

Re: Single pixel hardware scroll?

2012-02-02 Thread Thomas Harte
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

Re: Single pixel hardware scroll?

2012-02-02 Thread Simon Owen
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

Re: Single pixel hardware scroll?

2012-02-02 Thread Simon Owen
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,

Re: Single pixel hardware scroll?

2012-02-02 Thread Simon Owen
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

Re: Single pixel hardware scroll?

2012-02-02 Thread Simon Owen
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,

Re: Single pixel hardware scroll?

2012-02-02 Thread Thomas Harte
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

Re: Single pixel hardware scroll?

2012-02-02 Thread Thomas Harte
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.

Re: Single pixel hardware scroll?

2012-02-02 Thread Thomas Harte
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

RE: Single pixel hardware scroll?

2012-02-02 Thread Adrian Brown
] On 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 simon.o...@simcoupe.org wrote: On 2 Feb 2012, at 10:24, Geoff Winkless wrote: If you're thinking of playing with stuff like

Single pixel hardware scroll?

2012-02-01 Thread Thomas Harte
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 scroll

Re: Single pixel hardware scroll?

2012-02-01 Thread david brant
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 whatever effect it thinks it is relying on doesn't work in Sim

Re: Single pixel hardware scroll?

2012-02-01 Thread Balor Price
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 Coupe. Can anyone

Re: Single pixel hardware scroll?

2012-02-01 Thread Simon Owen
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