spaceball events GLUT compatibility

[John Tsiombikas-2]

Hi,
I just had the opportunity to run the spaceball example program I've
written along with the linux spaceball support, on MacOSX using the
native GLUT which apparently supports spaceball events.

What I've noticed is that I'm getting inverted values on both the
translation and rotation Y axis from the original GLUT from what my
example expects.

Now I can't be certain that's not something to do with the space
navigator driver on MacOSX or some obscure inversion setting there, and
I don't seem to have any GLUT programs using spaceball events so that I
can test if they behave properly with the new freeglut spaceball code or
if indeed I should invert the Y values...

So what do you thing I should do? Should I flip the Y values freeglut
produces to match the behaviour I'm getting on mac os x's glut? Does
anyone have any GLUT spaceball programs in mind that I could run and
see what they expect from the Y values?

What do you think?

--
John Tsiombikas
http://nuclear.sdf-eu.org/

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[John F. Fay]

One guiding principle here is the "principle of least surprise," both
for the user and for the maintainer.  If there aren't any obvious
settings in the driver, then I would invert the Y-axis event
directions for the Mac OSX and put in some extremely clear and
specific comments into the code as to what you are doing and why.

         - John

At 01:44 AM 11/8/2009, you wrote:

>Hi,
>I just had the opportunity to run the spaceball example program I've
>written along with the linux spaceball support, on MacOSX using the
>native GLUT which apparently supports spaceball events.
>
>What I've noticed is that I'm getting inverted values on both the
>translation and rotation Y axis from the original GLUT from what my
>example expects.
>
>Now I can't be certain that's not something to do with the space
>navigator driver on MacOSX or some obscure inversion setting there, and
>I don't seem to have any GLUT programs using spaceball events so that I
>can test if they behave properly with the new freeglut spaceball code or
>if indeed I should invert the Y values...
>
>So what do you thing I should do? Should I flip the Y values freeglut
>produces to match the behaviour I'm getting on mac os x's glut? Does
>anyone have any GLUT spaceball programs in mind that I could run and
>see what they expect from the Y values?
>
>What do you think?
>
>--
>John Tsiombikas
>http://nuclear.sdf-eu.org/
>
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>Let Crystal Reports handle the reporting - Free Crystal Reports 2008 30-Day
>trial. Simplify your report design, integration and deployment - and focus on
>what you do best, core application coding. Discover what's new with
>Crystal Reports now.  http://p.sf.net/sfu/bobj-july
>_______________________________________________
>Freeglut-developer mailing list
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[John Tsiombikas-2]

On Sun, Nov 08, 2009 at 07:38:12AM -0600, John F. Fay wrote:
> One guiding principle here is the "principle of least surprise," both
> for the user and for the maintainer.  If there aren't any obvious
> settings in the driver, then I would invert the Y-axis event
> directions for the Mac OSX and put in some extremely clear and
> specific comments into the code as to what you are doing and why.

I looked into this a bit more. I downloaded the GLUT 3.7 source and
tried ran a demo called dinomove which uses the spaceball callbacks. The
movement seems correct on all axis.

Also I looked through the relevant bits of the GLUT source code
implementing spaceball events on IRIX, and it passes the motion events
directly from the device to the callback without inverting any of them,
which is exactly what I'm doing with the freeglut spaceball code too.

So, I think we should leave it as is for the moment and keep an eye out
for any bug reports regarding any incompatibilities.

--
John Tsiombikas
http://nuclear.sdf-eu.org/

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