Mail Archives: djgpp/1999/11/24/18:35:21
Shawn Hargreaves napisał(a) w wiadomości: ...
>Chaos writes:
>>> VESA is buggy. Allegro successfully works around the bugs.
>>
>> ???
>> What you meen? My philosophy is that: If Allegro can do it
>> I can do it too.
>
>Of course. But the trouble with writing VESA code is that many
>(probably most) VESA drivers are extremely buggy, so no matter
>how well you write your code, it will still fail on some machines
>due to things that are outside your control. It would be nice if
>we could get away with this, but in the real world when your
>program crashes, most users will blame you for it, so it is nice
>if you can try to work around some of the more common driver bugs.
So it apears that even covering most of VESA errors I won't be 100% sure if
my aplication succeds due to still new video cards appearing?
Well, I think even Allegro will be weak at this field, apart from that that
it is great by the way :-)
>Allegro certainly isn't perfect in this respect: if a driver is
>truly broken, there isn't anything you can do about that. But it
>has been through several years of intensive testing and tweaking
>to make it work on many different setups, which is hard to
>duplicate yourself unless you have a huge test lab (I couldn't
>have done it all myself either, but many people have debugged
>various parts of the code on different machines, and found fixes
>for specific problems that were affecting them). Writing your
>own code is very likely to produce more compact results, and
>you should easily be able to make your code 'correct', but it
>is unlikely that you can replicate all the obscure tweaking that
>has subsequently gone into the Allegro routines...
Unfortunatelly I don't have an "army of programists" (as mentioned in
previous post) to test evry possible configuration.
However I think I can supose that few basic functions will be implemented
quiet well. The problem is to use only most popular functions and to deal
with all task. Hmm, it's a pretty big challange.
>>>> Now i'm wondering if I can do it safelly. Can I stick with
>>>> printing text messages such as timer or player name using
>>>> only printf-family functions.
>>
>>> They don't work on all cards.
>>
>> Why?
>
>Because not all VESA drivers bother to provide any text output
>functions. And this isn't actually a bug: the spec says that they
>are allowed not to do this. So if you want your program to work
>reliably on all machines, you cannot use printf() type functions
>in VESA graphics modes, and must write your own text plotting code
>instead. Store your own font graphics as part of the code, and
>draw them to the screen as a series of pixels in the same way as
>for any other graphics: that's not hard to do, and far safer than
>just hoping the BIOS will do this for you.
...and far faster. Thnx that's what I want to hear: "there was no need in
implementing printing text procedures".
I would like to ask you a question, as expirienced VESA and video
programmer:
Do I really have to implement VESA 1.2 Bank Changing?
I' ve searched within my friends someone with video card old enough not
having VESA 2.0.
I've only found 1 guy besides using UniVbe. So, do I must stick with slow
(int 0x10 yuck!) bank changing?
Thnx for eventual answer.
>
>
> Shawn Hargreaves.
3mcie sie.
-=| Chaos |=-
e-mail: chengin AT alpha DOT net DOT pl
chengin AT polbox DOT com
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