Were there any custom graphics modes?

[LoTonah]

Hi everyone. Pardon my ignorance on the topic, but did anyone ever come up with other graphics modes on the ST? I obviously know about the two color modes and the monochrome hi-res mode, but did anyone ever come up with a mode that used more colors, or a custom resolution? If so, is there source code and/or tutorials?

 

Thanks!

[Rybags]

There's the "Spectrum 512" mode that IIRC uses MOVEM.W instructions to block reload the pallette registers 3 times per scanline allowing 48 colours per scanline.

 

You could also do APAC-like modes by mixing scanlines of dark colour info with ones with luma on a per-scanline basis but that would work with a PAL TV only.

 

Then there's all the software overscan stuff that uses switching tricks among refresh rates/modes that removes one or more border regions, the resolution stays the same just the graphics area gets bigger.

 

I think there's also hardware projects to add a second Shifter to allow more colours in lores.

 

But, on a standard machine I don't think there's any way to have resolutions other than the 3 default ones with their 16/4/2 colour choices.

You could do stuff like multi-playfield parallax/overlapped scrolling in lores but you'd lose colours not gain them.

[eshu]

Hi everyone. Pardon my ignorance on the topic, but did anyone ever come up with other graphics modes on the ST? I obviously know about the two color modes and the monochrome hi-res mode, but did anyone ever come up with a mode that used more colors, or a custom resolution? If so, is there source code and/or tutorials?

 

Thanks!

 

Something called overscan, which removes the borders was possible with some very clever coding, this could extend the resolution of low-res mode from 320x200 up to about 416x274 but I don't think it would have all been viewable on a normal tv, I believe a similar technique was possible in medium res to. See http://alive.atari.org/alive9/ovrscn1.php and http://alive.atari.org/alive11/oscan2a.php.

 

It was also possible to to increase the number of colours available by rapidly changing the pallete e.g. http://www.asterius.com/atari/spectrum.html.

[oky2000]

Well Spectrum 512 just does raster changes to the pallet but there was something for the ST early on called Quantum Paint.

 

This little bad boy did all the Spectrum did and also created a new C64 IFLI style interlaced colour mode in lo-res to simulate 4096 colours on a 512 colour stock ST (ie before STE was launched). It also had the ability to load in Amiga HAM mode pics too. Great stuff. Review of this package will be in the first issue of my website e-zine magazine too

[OldAtarian]

The ST also had a virtual screen in which what you saw on your monitor was only a window into a much larger landscape. You could scroll off the edges to reveal the parts of the virtual screen that weren't visible.

[Math You]

It was also possible to to increase the number of colours available by rapidly changing the pallete e.g. http://www.asterius.com/atari/spectrum.html.

Could anything like this be done using the Atari ST's medium resolution?