Re: [MiNT] W and MacMiNT

[Oddie Jonathan <oddie@bvsd.k12.co.us>]

>> I just tested it on my performa 575. The screen doesn't work-I get 8 little
>> boxes at the top of the monitor instead.
>> Funnily, a similar kind of thing happens on the PB150 when I have the screen
>> set to 4 colors rather than 2. But I made very sure to set the performa monitor
>> to black & white... :( I'm a bit depressed.
>
>Maybe 575 uses a 'monochrome' 8-bit planar mode? :-/

I think the 575 (and probably most other macs with color monitors) has the lines
longer in memory than they logically ought to be. (e.g. a 640 pixel line
should be 80 bytes long, but it isn't) The 575's video goes up to "thousands
of colors" which is 16 bits per pixel, and I think they keep the line length
(in memory) the same for all color modes.

Some experiments with Macsbug seem to support this theory... I'll see what
I can find in Inside Mac on the subject tonight.

Is there a way to tell the PMONO driver that lines are longer than they
should be?
>
>> After giving up last night, I had the thought that maybe the screen width is
>> not a multiple of 32 pixels (something that PMONO driver requires). I 
>> _really_ hope that's the problem, cause otherwise I'm seriously up the creek
>> without a paddle...
>
>Yeah... BMONO (which doesn't need long alignment) is more portable
>although a bit slower.

Turns out that's  not the problem, but I'll add some code for the BMONO driver
in mac.c in case someone has a screen which needs it.

>
>> I'll check it out when I get home tonight.
>> So anyone testing the W server on MacMiNT should if possible set their
>> screen size to 640x480 as well as setting monitor to black and white.
>
>A direct-8 driver would be nice :)).  What kind of graphics modes
>different Mac models (for which MacMiNT works) there are?

There are three different kinds of bitmaps used by Color Quickdraw: fixed,
CLUT, and direct. Fixed and CLUT (color look-up table) are basically the same,
both use palettes, but with a CLUT device you can change the palette.
When in <= 256 colors modes, the screen acts as either a fixed or CLUT device.
If it's in "thousands" mode, it's a direct device with each pixel represented as
one 5-bit value for each RGB color, plus one padding bit. In "Millions" mode
it also acts as a direct device, but I don't recall exactly how many bits are
used per pixel...

The upshot of all this is that there isn't currently a W color driver which
will work on a color Mac screen. How hard would it be to make a new driver
based on direct8 that would use a palette rather than direct values?
You could then run it in 256 color mode...

Thanks

ttfn
Jonathan