JD Fenech wrote:
>
> I actually posted this to the feature requests awhile
> back, but I thought it would be seen if I posted it
> here for everyone. Curt mentioned that it might not
> be too difficult to implement this. I'd try to do it myself,
> except I'm definitely not ready for any fancy GL programming
> yet, or ready to fiddle with the FlightGear code yet.
>
Well, in principle, I like the idea, but I have 2 arguments against it.
1). The idea that the night sky is full of color stems more from science
fiction and Hubble space telescope imagery than from direct
obstervation. Go outside on a particulary bright night and have a look.
Personally, after a little getting used to, I'm able to observe that
betelgeuse, in Orion, has a reddish tint to it, and mars has an orange
color. Although other peoples eyes might be more sensitive, the point is
that while observing the stars from an illuminated cockpit environment,
much of the subtleties of the skies are lost, and color vision is one of
the first.
2). Since our eyes are observing the sky under less than favorable
conditions, you obviously need to compensate for it. We don't want to
draw the sky how is is, but how we perceive it! That means that you not
only need to calculate the correct RGB color but also how well the eyes
are responding to these colors.
[To illustrate this point: While on holiday in south-west USA last year,
I tried to make a photograph of the constellation of Orion. Looking back
at the developed films, I was completely surprised by the amount of
color in them. Of course, I know that stars are colored, but I forgot
that color film is equally sensitive to dim as it is to bright colors,
whereas the naked eye is only sensitive to color under bright
circumstances.].
As for planets being brighter than stars, the problem is that in OpenGL,
we need to scale orders of magnitude to values between 0.0 and 1.0.
This makes it virtually impossible do to exact brightness mapping. We do
scale planets down to their proper magnitude, but once their RGB exeed
1.0, we need to trim them down to 1 again.
Also - quoting Steve Baker - "this is a Flight Simulator, not a
planetarium". :-)
Regards,
Durk
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