Celestia Forums

The render path "OpenGL Vertex Program" still ignores the Ambient Light setting on my system.

When the Ambient Light is set to Low or Medium, for example, the night side of Mars is drawn as dark as if Ambient Light were set to Off. All the other render paths make Mars brighter on the night side when Ambient Light is turned up.

It'd be useful if someone with a Radeon card could verify whether or not Ambient Light does anything when vertex shaders are enabled.

System:
256MB 500MHz Pentium III, Windows XP Pro SP1
128MB Nvidia GeForce4 Ti4200, Detonator 43.45, OpenGL v1.4.0
Celestia v1.3.1 prerelease 3

Does this bug occur with all planets? Or just the ones with bump maps?

--Chris

Yes, it looks like it's related to bumpmaps.

The following tests were done using the default solarsys.ssc (except for Pluto )

1) Using the OpenGL vertex shaders rendering path and with ambient light set to None, Mercury's nightside is partially illuminated.
It is not illuminated in the other rendering paths. The illumination level is identical when using the OpenGL vertex shaders rendering path no matter what ambient light level is selected.

2) Venus with and without clouds looks correct in all rendering paths and Ambient Light levels.
(Although the center of the sunlit side does get brighter when using the "Nvidia Combiners" rendering path when Ambient Light is turned on.)

3) Earth looks correct in all rendering paths and Ambient Light levels.

4) Mars looks correct in all but the OpenGL vertex shaders rendering path. Unlike Mercury, its nightside is dark.

5) Jupiter looks correct in all rendering paths and Ambient Light levels (sunlit side brightens when using the "Nvidia Combiners" rendering path when Ambient Light is turned on.)

6) Saturn looks correct in all rendering paths and Ambient Light levels. (sunlit side brightens when using the "Nvidia Combiners" rendering path when Ambient Light is turned on.)

7) Uranus looks correct in all rendering paths and Ambient Light levels. (sunlit side brightens when using the "Nvidia Combiners" rendering path when Ambient Light is turned on.)

8 ) Neptune looks correct in all rendering paths and Ambient Light levels. (sunlit side brightens when using the "Nvidia Combiners" rendering path when Ambient Light is turned on.)

9) The Moon is like Mercury: Using the OpenGL vertex shaders rendering path and with ambient light set to None, the nightside is partially illuminated. It is not illuminated in the other rendering paths. It isn't quite as obvious as on Mercury, though. The nightside is much darker when using the OpenGL vertex shaders than the other rendering paths when Ambient light is enabled.

10) the ISS model looks correct in all rendering modes and ambient light levels when it's in sunlight.

I hope this helps.