On 1999/Oct/04, Jos Hulzink wrote:
> > into KGIcon, it's best (I have readed the GGI tech. docs, and it seems to be
> > a bit difficult).
>
> The ViRGE has completely functional vertical retrace interrupt code, but
> at the moment, nothing is done with it. Reason: I have not seen a
> mechanism to get the sync to userspace neatly. (Maybe some
> CHIP_WAITFORRECTRACE ioctl ? We never intended to be real-time, so some
Not, FB has now a good way of use it:
[ /usr/include/linux/fb.h ]
#define FB_ACTIVATE_VBL 16 /* activate values on next vbl */
It can be *very* usefull to do page flipping. You still have the
problem of dumping buffers into video memory, but at least, this is
something... I understand that a waitretrace ioctl makes no sense.
Well, let me imagine a bit. Applications has two main ways of
writing his data into video memory, either with page-flipping (very easy to
handle, I think) or with double (triple, ...) buffering, right, or I have
*very* old ideas?. So, _maybe_ it would be a good idea if kernel could
handle and dump the memory buffer for you...
You only call the FBIODUMP_BUFFER ioctl, passing as parameter, a
structure like this:
struct kgi_buffer{
void *buffer;
uint16 x0, y0;
uint16 width, height;
}
and the buffer is dumped when it's possible, getting the proccess locked
until this is done. In some cards it it could be done with HW accel by AGP?
It's a very simple idea, and surely more people thought in it
before, what's the problem with it?
I know that the idea of kernel doing it wouldn't like many people,
and I know that in some systems it isn't possible to dump big buffers in a
vertycal retrace/blank, but I can't see a best solution.
> > I'm still porting 3D routines from DOS to Linux, I have finished
> > flat and gouraud, and will start with zbuffer. And a Cube is the easyest
> > way, IMHO, for finding bugs in the ported routines, it isn't the demo itself
> > :-D
>
> You're talking about software emulation of the functions you describe or
> hardware support ?
Both. In the port I'm using extensive the hardware accel if possible
(is for demos, I _may_ use as much resources as available)
> Want to help writing 3D accelleration in the KGIcon S3 Virge driver ?
Yes, I really want, where can I start searching the HW specs of the
3D commands?
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