[James Ross]

BB25187, on 19 January 2014 - 01:27 PM, said:

I created the patch from revision #1947, meaning it doesn't contain the changes made by James - this was easier for me because it didn't create any conflict. Several things are still missing in my code: stars and moon are not impacted by fog, whereas they should. Furthermore my implementation of the sky fading is a bit crappy and should be cleaned up. Anyway: it will allow you to compare the two methods. I am sure that the revision #1949 by James is a good basis and only needs minor changes.
I hope it helps,

Let me know when you're happy with the sky/cloud/star behaviour and I'll drop the code in. :)

The reason for the difference in manual fog control is because I switched the fogCoeff around from being an arbitrary number (that changes meaning depending on whether you have DM enabled or not) in to a 'visibility' distance value.

[RTP]

Nice fog.
But:
The steps are too big.
The horizon remains visible.

Great improvement aniway.

Regards,

[Csantucci]

Bonjour Vincent,
I have tested your fog. I like very much the fact that now the fog density steps are very smooth, and from that point of view the solution is OK to me, and I suggest that your solution replaces that of James.
However the sky problem is not solved, as it is not solved in James' solution. Attached you find three pictures made with max fog density, one with overcast sky, one with overcast sky and view towards distant mountains and one with clear sky. In all cases the sky is very well seen, and the horizon is very neatly seen also for distant mountains that are about 40 Km far away. So unfortunately that problem is still pending.

Overcast sky, near view: Note the unnatural skyline caused by the two trees

Overcast sky, DM view:

Clear sky, near view: nice to see that the fog is brighter, but again note the unnatural skyline caused by the two trees

[BB25187]

Hi Carlo,

Thanks for the test. It seems that the contrast between the sky and the horizon remains higher in your case. I will post a video later on to show the effect on the Gothard route under construction by Thomas to illustrate this difference (it is not perfect either, but it contains at least one good reason to be optimistic). One possible cause is the different cloud texture that I am using. This is to be confirmed. I am even more surprized of the effect you get by clear weather. Maybe I forgot to include another change in my patch? In any case this needs to be investigated and worked on, hoping we can get a better tradeoff. I plan to spend time on the topic during the next week-end.

Regards
Vincent

Edit - PS: Here is the video. As you can see:
- When the fog comes by a clear weather, the sky becomes greyer as on your picture. I must understand why.
- When the fog comes by a cloudy weather, there is a point where the horizon and the sky have nearly the same color. This is the reason why we can stay optimistic.
Of course, once modified (and improved hopefully!), the whole thing will have to be tested at different hours of the day and night!

Vincent

[Csantucci]

Under Vincent's suggestion I made a check and result was that I didn't patch well release 1947. So pls. don't consider above pictures, sorry. I redid the patch and below are the pictures I get.

This is a picture with the most clear weather:

I have some comments on it. While I like the fact that the mist increases smoothly with distance, air is often crisper. This is a real picture I took some years ago more or less at the same place, and it wasn't the crispest day:

One could say: well, Bernina weather is an exception. This is a picture I took this morning with the telepicture lens from my home in Turin, Po plain: the mountains shown are around 40Km and more far away, and there are many days like today:

So I kindly ask to have the possibility to set also a crisper weather.

Coming to the fog cases:
This is a fog picture taken with non overcast sky, fog not to maximum:

I like it.

This is a fog picture taken with non overcast sky, fog to maximum:

Much better than before, however skyline is still visible.

This is a fog picture taken towards the sun with non overcast sky, fog to maximum:

The effect of reduction of sun diameter and brightness is very nice, but sun never disappears.

This is a fog picture taken with overcast sky to maximum and fog to maximum:

The darkness is OK, but the skyline is still visible.

And this is what the poor Glacier Express passengers see if there is maximum fog:

Thanks also to the darkened wagon windows, the effect is nice ;)

So, except in the case of no fog and no overcast (where I preferred the old settings as minimum fog value), this changes are a very good improvement, however I hope that it will be possible to completely erase the skyline with high levels of fog. :derisive:

Thank you Vincent for the time you take on this issue and sorry again for the time you lost because of my fault!

[BB25187]

Hi Carlo,

Thanks a lot for this new test and for the very helpful pictures.
As I am now sure that we get the same effects, I can envisage to work further on the improvements you suggest.

Regards
Vincent

[Csantucci]

I received by Vincent a further patch managing fog and I want to say that the results are outstanding!
Here there is a sequence of pictures, from maximum clarity to maximum fog. As can be seen, the skyline gradually disappears from far away and, by increasing fog, also from the vicinity. I want to stress that maximum clarity is not the default, that is default is a bit of mist, and maximum clarity is reached by decreasing fog. This is also a wise idea. By the way the fog increase-decrease commands act very smoothly.






This is a view taken from the same location as preceding posts. If you maximize the picture you will seen the signal's light.

This is what the poor Glacier Express traveler sees. The Palü Glacier has completely gone.


Only two small problems:
With thick fog there is a point on the sky that looks like this:

With a very overcast sky the skyline appears

but both cases shown here are extreme situations.

I congratulate with Vincent, and kindly ask that his patch become part of the OR release.

[railguy]

That fog looks great. One other comment related to colors. Most people who do not live at high altitudes don't realize that the sky does have a very deep blue color and the UV at higher altitude combines with clear air does give a "bluish" tint to the landscape, as your photo suggests. That is not an anomaly with the photo--that is how it looks at that altitude. I know--I live at 8,000 ft. altitude and work from there up to 10,000+. I would be nice to be able to adjust the "tint" of the landscape in OR to reflect different altitudes, atmospheric humidity and air pollution levels, etc. Maybe, someday, when the full weather module is developed for OR?

That is a beautiful photo. Being a mountain and train lover, Switzerland is on my places to visit someday . . .

[BB25187]

Hi all,

Thanks Carlo for the pictures. I am happy that you appreciate those modifications.
As for the visible skyline with large values of the overcast, one possible solution would consist in implementing a control outside the shaders, so as to limit the overcast when fog is very dense.
I don't know yet how to resolve the zenithal blue point on the sky.
As for the blue tint, it seems very close to the point raised in another topic. This was doable with MSTS, thanks to the direct and ambient lights defined in the environmental files. So, if the support is ported into OpenRails, this might be a good solution?

Cheers

[James Ross]

BB25187, on 26 January 2014 - 06:23 AM, said:

Thanks Carlo for the pictures. I am happy that you appreciate those modifications.

Thank you for the patch; I have added it (unchanged) in X1963.