Mail Archives: djgpp/1997/12/09/09:50:10
Salvador Eduardo Tropea (SET writes:
>> In an old pascal Xlib i've ported to djgpp, there is resolution
like
>> modex 400x300 (for this one your monitor have to support it) or lots
of
>> 360x480,360x400,360x360,360x240 the same in 320x... So if people want
to
>> get my initialization code for them, say it !!
>
> Most of these modes are supported in Allegro. I think you can check if
some is
> missing and send to Shawn the information for this mode. In this way
all the
> Allegro users (and that's a lot of people ;-) will be benefited.
Yeah, Allegro supports all those modes (also some 256x*, 376x*, and a
400x600 resolution). The trouble is that the more severely tweaked
sizes,
in particular the 400x* modes, depend on some very odd frequencies that
don't work on every graphics card and monitor. So they aren't generally
that useful if you want to be sure your program will run on any PC...
The 320x* and 360x* modes seem to work reliably on any hardware, but
the larger versions of these suffer from a lack of video memory. You can
double buffer a 320x400 screen, and triple buffer a 360x240, but the VGA
only has enough video memory for a single page of 320x480 or 360x400,
which make them less useful for realtime animation...
Anyway, if you have the register values for any tweaked modes that
Allegro doesn't currently support, I would love to add them! If you look
in the modex.c file, there is a block of VGA_REGISTER structures
for every supported mode, which are listed in the xmodes[] table. This
makes it very easy to add extra resolutions, as long as you know the
magic numbers...
Shawn Hargreaves.
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