Re: Programming graphic systems

[Dimonax <dimonax@nospam.net>]

On Thu, 23 Apr 2009 11:27:59 +0200, Olivier Scalbert wrote:

> Hello,
> 
> When playing with my GPS, I was thinking of the beautiful graphic
> systems used in safety critical environment (medical, aircraft, ATC,
> ...). I assume lots of them must be written in Ada. I was asking myself
> how are they programmed mainly at the graphic level. Does the
> application part use a graphic toolkit provided by the graphic board
> manufacturer or do you have to program all the graphic primitives
> yourself in Ada (as Bresenham line algorithm, ...) and written to the
> raster memory (which must be very cool!) ?
> 
> Thanks for your info,
> 
> Olivier

Actually if you know how to write callbacks to a C API with Ada, then 
getting started isn't all that complicated. There are a few people even 
in this newsgroup that have written small graphics engines on the OpenGL 
API.

However if you plan to utilize tasking and such for your programs, you'll 
need access to the technical documentation of your video hardware, since 
OpenGL isn't multithreaded and DirectX is pretty much a black box when it 
comes to serious graphics programming. You might find a graphics card 
vendor who's drivers also include non-standard support for tasks and 
threads, but it's unlikely.

Of course I'm referring to the common hardware your likely to find at 
your local computer shop. The requirements for the big multimillion 
dollar flight sims are going to be completely different.

I played with this a few years ago using a Matrox G400 video card and the 
documentation which, at the time, was freely available. It can be done, 
and done well, but it takes a lot of patience to get it running.

Also if your running on Linux, you'll find the half-in kernelspace half-
in userspace architecture infuriating(one reason I decided to write my 
own driver.)

The best card to learn the ins and outs of this type of programming, with 
any language(not just Ada) is one where the tech docs are open. Lately 
ATI has been pretty fortcoming with thier tech docs, so I'd start with 
them.

Freejack