Eclipse Shadow Problems

[Reiko]

I not know why I have this problem now since I never had it before but eclipse planets/moons are showing oddly in Open GL 2.0







This is with Celestia 1.6.0 rc2 on windows vista 64x using NVIDA GeForce 9400 GT card with the latest drivers which are the 185.85 as far as I can tell.

The problem wasn't there previously and is now. Tried reinstalling the drivers and installing rc3 and it still does it.

[t00fri]

Reiko,

how about the rendering of the standard eclipse shadows due to the Galilean moons in case of Jupiter, for example? Is the problem only with eclipse shadows or also with other shadow renderings like e.g. Saturn's shadow on its rings?

Fridger

[Reiko]

Strangely enough Jupiter's moons look fine in shadow and ring shadows work normal as well. Small shadows moons cast on large planets look fine.

The first two screen shots are of a planet in a double planet system. Only that planet shows those oddities but not the sister planet. The second screen shot is a moon in the shadow of a gas giant. The moon has atmosphere and clouds and comes out looking odd while in shadow.

[Reiko]

I've been able to narrow the problem down in regards to the binary planet seen in the first two screenshots. It seems to have to do with the specular color and power. I set it to match that of the sister planet and the graphical glitch miraculous disappears.

[selden]

Reiko,

Can you provide the SSC file that you're using?

I'm wondering if some of the values you're using are outside the bounds of what Celestia expects.

[Reiko]

Ok here is the original ssc.

ReferencePoint "Vulcan-T'Khut" "40 Eri A"

{
Visible true
Clickable true

EllipticalOrbit {
Period 0.481
SemiMajorAxis 0.605
Eccentricity 0.003484
Inclination 2.1680
AscendingNode 223.0539
ArgOfPericenter 157.92
MeanLongitude 257.960
}
}


"Vulcan" "40 Eri A"
{
Class "planet"
Texture "vul1A.png"
Color [ 0.7 0.55 0.65 ]
SpecularTexture "vulSpec.png"
BumpMap "vulBump1A.jpg"
BumpHeight 2
NightTexture "vulNight.png"

SpecularColor [ 0.5 0.5 0.55 ]
SpecularPower 20.0
HazeColor [ 0.43 0.72 1 ]
HazeDensity 0.5
Radius 7809.45


Atmosphere {
Height 70
Lower [ 0.30 0.52 0.65 ]
Upper [ 0.26 0.47 0.84 ]
Sky [ 0.30 0.48 0.82 ]
CloudHeight 7
CloudSpeed 0
CloudMap "earth-clouds-hs-32k.ctx"

Mie 0.001
MieAsymmetry -0.25
Rayleigh [ 0.01 0.0015 0.0006 ]
Absorption [ 0.0010 0.0060 0.0100 ]
MieScaleHeight 14.0
}

OrbitFrame {
EquatorJ2000 { Center "40 Eri A/Vulcan-T'Khut" }
}

BodyFrame {
EclipticJ2000 { Center "40 Eri A/Vulcan-T'Khut" }
}


EllipticalOrbit {
Period 9.29
SemiMajorAxis 67284
Eccentricity 0.0009
Inclination 2
MeanAnomaly 1
}
RotationPeriod 29.1
Obliquity -15.0
RotationOffset 280.5

Albedo 0.39

}



"T'Khut" "40 Eri A"
{
Class "planet"
Texture "charis3.png"
NormalMap "charis3normal.png"
NightTexture "charis3night.png"

Color [ 0.3 0.3 0.3 ]
SpecularColor [ 0.5 0.5 0.55 ]
HazeColor [ 0.7 0.55 0.35 ]
HazeDensity 0.45
Radius 4640


Atmosphere {
Height 50
Lower [ 0.9 0.65 0.35 ]
Upper [ 0.5 0.35 0.3 ]
Sky [ 0.93 0.55 0.35 ]
CloudHeight 6
CloudSpeed 70
CloudMap "charisclouds.png"

}


OrbitFrame {
EquatorJ2000 { Center "40 Eri A/Vulcan-T'Khut" }
}

BodyFrame {
EclipticJ2000 { Center "40 Eri A/Vulcan-T'Khut" }
}


EllipticalOrbit {
Period 9.29
SemiMajorAxis 107284
Eccentricity 0.0009
Inclination 2
MeanAnomaly 180
}
RotationPeriod 32.1
Obliquity -15.0
RotationOffset 280.5

Albedo 0.39
}

On the planet labeled "T'Khut" I made the specular color and specular power the same as "vulcan" and it looks normal again.

[selden]

I don't see any SpecularPower at all specified for T'Khut. That is one problem. Otherwise the ssc looks OK to me. There might be some issues with the actual contents of some of the png texture files, but I have no way to determine that.

[Reiko]

There is not a problem with the textures because if you move the planet into its own orbit around the sun the glitch isn't there. Also if you remove all of the textures the glitch is still there. I just copied and paste the spec color and power from the first planet and applied it to that one and the glitch vanished.
The odd part is I don't recall ever having this problem before.

[selden]

When using a SpecularTexture, both SpecularColor and SpecularPower must be specified. Celestia's rendering engine does strange things if you leave either of them out, as you've found.

[t00fri]

When using a SpecularTexture, both SpecularColor and SpecularPower must be specified. Celestia's rendering engine does strange things if you leave either of them out, as you've found.

Which presumably means that somewhere a default value is lacking in the code...

Fridger