[Kstars-devel] OpenGL: the beginning

[Jason Harris]

Hello,

> In my case './configure' did not complain that I did not have the
> glutg3-dev package installed so when I typed 'make', it did not work. Now I
> have installed glutg3-dev and it compiles fine.
>
Yes, I didn't modify the configure script for this little test.  

> > Right now, it just displays the coordinate grid, and you can scroll with
> > the arrow keys and zoom in/out with the +/- keys.  It seems really
> > smooth on my system, but I have hardware acceleration, so I don't know
> > how software openGL compares yet.
>
> My laptop does not have graphics hardware acceleration and it also works
> smoothly here.
>
Good to hear :)

>  If the way we represent objects changes perhaps we should define at least
> two more classes, a sort of 3dStaticPoint and 3dDynamicPoint. The first one
> should represent a vector in cartesian and spherical coordinates. The
> second one should inherit from the first one and should have a constructor
> with 3dStaticPoint, t0, and v, where 3dStaticPoint is the (x,y,z) position
> at time t0 and v is (vx,vy,vz) to allow for proper motions. A position for
> time t would be obtained by doing:
>  r' = r + v (t-t0)
> SkyPoint should then inherit from 3dDynamicPoint. In this way the
> transformation of coordinates from spherical to cartesian ones will be very
> simple. We will also need some function to compute distances from
> magnitudes, when parallax is not available. Are there objects without a
> measurable parallax in the modified Hipparcos catalogs you made, Jason?.
> And I have another question, does the Hipparcos catalog have Vlsr for some
> sources?.
>
One problem with this is that proper motions are defined on the surface of the 
celestial sphere; constant-velocity motions in RA and Dec will diverge from 
constant-velocity motions in X,Y,Z.  So I think we should still represent 
proper motions as delta-RA, Delta-Dec and then convert to X,Y,Z.  Unless you 
are talking about actually placing the stars in a 3D volume, using their 
parallax distances.  I was thinking of still placing them on the celestial 
sphere.

Jason

-- 
-------------------------------
KStars: KDE Desktop Planetarium
kstars at 30doradus.org