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Re: Grabbing the pointer with OpenGL

On Thu, 12 Apr 2001, Steve Baker wrote:

> > > > I warp the pointer in the glut callback function. (And sets a flag to
> > > > avoid endless loops - is there a smarter way to avoid this?)
> > >
> > > The glut *render* callback - right?
> > 
> > No, actually in the callbacks from glutPassiveMotionFunc and
> > glutMotionFunc. I choose this, to try an keep the mouse at the center.
> Hmmm - I wonder if that could be a part of your problem.
> Try it in the render callback.

OK, I will. Although I fail to grasp why it should make a difference. It
makes it a bit harder to avoid looping, I think.

> > But this is software rendering. And, I do not cull to the viewfrustrum (I
> > read all your faqs, btw ;-) yet.
> If you are truly intending to stick with software rendering, I wouldn't spend
> too much time on view frustum culling. Probably 90% or more of your CPU time is
> going into filling pixels - and hence any effort spent on optimising the rest of
> the code can at most get you a few percent frame rate increase.

I do not intend on software rendering, it is just that my 3d hardware can
not render to a window, and it is often convenient to run the program in a
window. I understand that people that have DRI support often run in a
window, and I would like to test my program running as such.

> Instead, look into techniques like portal culling that reduce the number of
> pixels that you draw that are actually only going to be tossed out by Z-buffer
> culling.
The stuff I am rendering is a terrain. I was under the impression that
portal techniques were not very appropiate for outdoor rendering? I intend
to implement something like ROAM eventually. 

> Personally, I think it's time to dump software rendering.  You can pick up
> really amazing 3D hardware for virtually nothing these days.  One small hit
> on your credit card and you have a 50x speedup.

I do not want to bore you with the details of my system or my economy or
the fact that my wife need 50 pairs of shoes (at least it seems that way
:-). Upgrading only the videocard is not really an option - there are no
AGP bus in this system, and I do not want to buy a highend video card with
a PCI bus. Very quickly I will be looking at $1000 and basically have to
upgrade 80 % of my system (no SDram slots either, btw, and I do not own a
ATX cabinet, and so on).

For now, I will simply assume that the low Hz is the reason, and not mind.



Mads Bondo Dydensborg.                               madsdyd@challenge.dk
Microsoft's stance in this brouhaha is, of course, hypocritical to the
point of being nauseating. 
    -     Eric S. Raymond on MS's demand that AOL use open protocols for IM

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