two eclipse shadow bugs

[selden]

While admiring Don Edwards' volcanic moon this evening, I noticed two bugs in the eclipse shadow rendering that I don't think have been mentioned before.

[url=http://www.lns.cornell.edu/~seb/celestia/vme1.jpg]
[/url]
(this links to a higher resolution image)

1) the edges of the shadow are saw-toothed
The planet casting its shadow onto the moon happens to be Mars as shipped with Celestia v1.2.5, not a 3ds object with a jagged limb.

2) when the shadow is cast on a night-light texture (on the day-lit side of the planet), the lights are dimmed instead of becoming brighter.
Note the glowing region in the lower right center which becomes dark in the shadowed area.

System specifics:
256MB, 500MHz P3, Windows XP Pro, SP1
128MB Nvidia GF4 Ti4200, Detonator 40.72 drivers
Celestia v1.2.5
Don Edwards' http://63.224.48.65/~impulse/Volcanic%20Moon.zip

[billybob884]

i dont get the jagged problem, but i do get the dark side problem

[Kendrix]

your "saw-toothed" problem is due to the size of the shadow texture...
256*256. I have modified my private version to have a 2048*2048 shadow texture and that problem goes away ! (unless you zoom to 3 km of the shadow... ;o) )

[Don. Edwards]

Kendrix,
Where in Celestia do you edit this setting? I have never seen anything about shadow textures.

[Kendrix]

in render.cpp

function : Renderer::init(int, int)

shadowTex = CreateProceduralTexture(256, 256, GL_RGB, ShadowTextureEval);

I have seen my code and in fact I have put 1024 intead of 256 (and not 2048).

The best would be to set the resolution dependant to the lores/medres/hires mode !