[Kstars-devel] skycomponents: update vs. updatePlanets vs. updateMoons

[Jason Harris]

Hello,

Do we need separate functions update(), updatePlanets() and updateMoons()?
The reasoning behind separating them is: 

most of the time, we just need to update the Horizontal coordinates of all 
objects in the sky; in that case, we use skyComponents()->update().  Less 
often, the Moons (Earth's and Jupiter's) positions need to be updated; in 
that case we'd call skyComponents()->updateMoons().  Finally, the eight 
planets + Sun need their positions updated even less often than the Moons; in 
that case, we'd call skyComponents()->updatePlanets().

It seems wasteful to have updatePlanets() and updateMoons() at the 
SkyComponents level of the hierarchy, because they are irrelevant for the 
vast majority of objects (i.e., all non-solar system objects).

Suggestion:  Provide updatePlanets() and updateMoons() only in 
SolarSystemComposite and its children.  We'd need to have direct access to 
the SolarSystemComposite in KStars, so we could just call 
"solarSystem()->updatePlanets()" when needed.  Similar arguments can be made 
for SkyComponent::addTrail(o)/removeTrail(o): there's no point looping over 
all the stars and deep-sky objects looking for an object with a trail, so it 
would be better to restrict this function to the SolarSystemComposite and its 
children.

What do you think?

Jason
-- 
KStars: KDE Desktop Planetarium
http://edu.kde.org/kstars