[SDL] Feature Query System (Was: Some multithreaded improvement to the event queue...)

Olof Bjarnason olof.bjarnason at gmail.com
Fri Sep 23 13:54:49 PDT 2005


On 9/23/05, Bob Pendleton <bob at pendleton.com> wrote:
> On Tue, 2005-09-20 at 19:52 -0400, Antonio SJ Musumeci wrote:
> > You do not need to understand the reason someone would want to use the
> > library in that way... but in my opinion not forbid them to do so. I see
> > no good reason to hide things from the developer. If the library chooses
> > between several methods to do something... I aught to be able to find
> > out which it chose and if i want override it. If he wants to shoot
> > himself in the foot I would gladly give him the gun and bullet. Steven
> > Johnson was correct... it's a difference in philosophy. I am an embedded
> > developer.
>
> Interesting. I suppose this is a philosophical difference. You see, the
> whole reason for having a library like SDL, in fact, the *only* reason
> for having a library like SDL, is to hide all these decisions so that
> the developer can get on with writing his applications without having to
> worry about how things actually get done. Without that philosophy SDL
> could not be machine and OS independent.

Well, I don't see how a program doing queries to improve certain
features of runtime operation implies the program beeing less platform
independent ..


>
> > When I develop libraries which have any flexibility built in
> > I provide querys to find out as much info about how the library is
> > working as possible... as well as hooks to allow the user to override
> > anything which doesnt break the core design. I've run into way too many
> > situations where i hack around something or had to redesign something
> > because an underlying library hid functionality or didnt provide a
> > robust enough interface. If SDL checks for certain CPU extensions to
> > decide which memcpy would be the best... it can easily give me the
> > knowledge as to which it chose and the ability to override or replace.
>
> I suppose that might make sense for the kind of embedded programming you
> do. It doesn't make much sense to me.
>
>                Bob Pendleton
>
> >
> >
> > Stephane wrote:
> > > Antonio SJ Musumeci wrote:
> > >
> > >> the SDL_Surface flags dont give you the full story. Just because you
> > >> dont get a HW surface if you ask for one doesnt mean the platform or
> > >> driver doesnt support it. Or finding out which blitter is being used
> > >> on a specific platform would be nice... anything SDL hides doesnt need
> > >> to be completely hidden. You only lose flexability and limit the
> > >> developer. On a x86 machine I want to know if a MMX or SSE accerated
> > >> functions are being used or if I run in fullscreen i MAY be able to
> > >> get a hardware surface.
> > >
> > >
> > > Think about it for a second. Why do you need that ? If all you want to
> > > know is whether the platform is fast enough for your stuff, benchmark
> > > it. That's the only way. MMX on a 166Mhz CPU is going to be slower that
> > > plain C on a 3Ghz one. Also, MMX is intel-specific, so looking at this
> > > flag will make it look like that G5 is slow.
> > >
> > > To prove my point I'll cite the similar example of an old OpenGL
> > > application that runs on windows.  That application used the
> > > windows-specific bits to query whether hardware acceleration was used,
> > > and refused to run if it wasn't. That was back in the days when a 200Mhz
> > > CPU was fast. Nowadays this application could very well run on a 3Ghz
> > > machine using software emulation, but the author was stupid enough to
> > > prevent it.
> > >
> > > Stephane
> > >
> > >
> > > _______________________________________________
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> > > SDL at libsdl.org
> > > http://www.libsdl.org/mailman/listinfo/sdl
> > >
> >
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> >
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