🚀 go-pugleaf

In article <1992Sep29.154829.59269@cc.usu.edu> sl8nl@cc.usu.edu writes:
>> Like is it impossible to access each plane in turn?
>
>Mode 13h is entirely linear...period.  No ifs, ands, or buts.  You have 64k of
>memory to work with, which gives you the 320x200x256 colors.
>
>> Can you use the set_address_high and set_address_low to pan the screen
>> around?
>
>No.

WRONG, please see below.

>
>> Can you use page flipping?
>
>No

WRONG again, see below also...

>
>> I have the feeling that the answer to all these questions. If so then
>> why would anyone want to use this mode? My current scrolly is so
>> processor consuming that I can't do anything else!! 
>
>Because it is simple.  there are some applications that don't require it.  As
>an example, I have written several games based in that mode.  Lessee, Wing
>Commander uses the mode (DPaint's Camera program was able to capture a
>screen.).  Most commercial software uses it, also.
>
>> Should I use Mode X from now on? I believe you can do the above
>> questions with  this mode, right?
>
>You betcha.  And there are a lot of experts here.  
>
>BTW, I'll be posting a sample demo with source soon that will have module
>music, color cycling, a 100 pixel tall scroll, and a graphic equalizer going at
>once.  It will be ModeX or Y, not sure yet.
>
>Take care,
>Joshua Jensen
>


Ok, the standard mode 13, 320x200 is very restricted, but it is possible
to kludge this mode, in a similar way to creating modex, so that
ALL 256k can be accessed, the screen can be scrolled, and therefore
flipped, which is just scrolling by a 'page'.  You can change the
logical width of the screen, you can use set address high and low
to scroll.  I posted a demo that does all of this...accesses ALL
256k, creating a 512x512 virtual screen, and pans around it.  Someone
who has it may want to post it, or I'll get to it this weekend.

This may be splitting hairs, I know I'll get flamed because the
original question was about mode 13 and not a derivative, but
if you're going through the trouble of using modex, you may as
well have a choice.  Modex gives higher resolution, but mode13
gives more free memory for storage of bitmaps and such.

-Fred

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