Jump to content

Stars intensity dramatically affect sun visibility and scene environment lighting even in full day light


Recommended Posts


Migrating to 2.16.1, I just stumble upon the fact that environment texture is used for stars (well, I probably missed it a few version ago, whatever). Previously, we simply had "environment_default" as the environment texture, all was good albeit no stars at night.

If I restore this texture to "stars_c.hdr", then we do have stars at night (ok) but if  CIGI sends the stars intensity a bit too high, then even at noon the sun is completely invisible, and the scene turns greyish and darker.

The default blend mode is Alpha blend. Setting "Additive" somewhat fixes the color.

Also the stars are fully visible in full daylight.

Restoring to "environment_default" fixes the sun visibility and the scene color, so nothing is actually lost, except the stars...


I understand that the environment texture could be used for other things, unrelated to stars and CIGI, but in the Sim use case, shouldn't the environment stars only be visible from dusk till dawn, and hence modulated not just by the CIGI stars intensity, but by the sun luminosity also?

To sum up and give some context: my expectation would have been that even if CIGI send stars intensity at max (eg: we fly to oil rig in the ocean with a perfect clear sky), then the stars should only be visible at night and not influence the daylight sun and scene color. Sim-wise, we diminish the stars intensity to simulate atmospheric fog or light pollution, not to simulate the day/night cycle.


Link to comment

The "problem" was probably here since a long time, but we never bothered before with stars... but now it appears as a wanted feature for night missions. Not really critical, but would be nice if it behaves as one may expect for flight sim.

Here is a view in 2.16.1 with stars_c.hdr, and IG sun around noon in winter, with stars at max (note you have to move the Stars slider to see the effect!)


Note how the sun disk is invisible and the image is greyish, the sky is dull.


Here is the same view with Stars at 0%


Note how the image is more colorful


Here is a view with the environment set to "environment_default" with "stars" at 100%


This one looks exactly the same with stars at 0%.

Link to comment
  • Create New...