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Kuax

Creating and editing sunset or sky textures

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Hello to all intending to edit sunset or sky textures

You can do this on your own. But to be honest: You’ll spend a lot of time if you want to see reasonable results. I think a basic software for doing this nearly unlimited is Paint.NET – you can download it for free. Being in it you’ll have a lot of possibilities in editing sky textures. In fs9 they’re all 24 bit-textures and 32 x 32 pixels in size – so be sure to save them in the same format.

The following is what I figured out by testing (so no guarantee – corrections or contributions are welcome!)
Don’t forget to backup your existing files.


How are they working, acting or blending together?

First you’ll recognize that there’s a bundle of textures (fs9 texture folder) just for sunset:

“sky_presunset1_0” to “sky_presunset1_9”
“sky_presunset2_0” to “sky_presunset2_9”
“sky_sunset_0” to “sky_sunset_9”
“sky_postsunset1_0” to “sky_postsunset1_9”
“sky_postsunset2_0” to “sky_postsunset2_9”

That’s the sequence they seem to be applied in fs9 – “sky_presunset1” to “sky_postsunset2” for one sunset event, “sky_presunset1_0” to “sky_presunset1_9” for different months or sunset styles, same applies to “sky_presunset2_0” to “sky_presunset2_9” and so on…

Each texture file number, e.g. “sky_presunset1_0” represents one month or two months or one sunset style and blends to “sky_presunset2_0” to “sky_sunset_0” to “sky_postsunset1_0” to “sky_postsunset2_0”. Unfortunately i didn't figure out which number refers to which month.

There’s no need to occupy one sequence, e.g. “sky_sunset_0 to “sky_sunset_9” with one and the same textures (as you see it very often in available sunset textures). If you prefer only one sunset style just do that, if you prefer variation, occupy them with different textures (if you want to watch the results, put them in the fs9 texture folder, start fs9, switch to different months and adjust sunset times to get them).

For testing purposes you may want to occupy them with one style (to be independently of the switched month and to be sure just to get the wanted test texture, also to test how the different season terrain textures are blending to your new sunset textures) and see how they’re working or blending together by adjusting different sunset times.

Be aware that all of the very above mentioned texture files are needed to display sky textures generally. There’s no way just to put in e.g. “sky_presunset1_0”, “sky_presunset2_0”, “sky_sunset_0”, “sky_postsunset1_0” and “sky_postsunset2_0” for testing purposes, if so or if one file of the very above mentioned is missing, fs9 just displays white sky.


Editing a texture file:

When you watch a sky texture file in an editor, you may think that the image is too small – just enlarge it. After enlarging it you’ll think that the resolution is to coarse (32x32 pixels) but that’s enough for fs9 – even relatively hard transitions in colour and brightness from one pixel row to another or from pixel to another (as perceived in the editor) are blurring sufficiently in fs9 to get almost smooth transitions.


Different pixel codes in a texture file (for reflections from ground, aircraft, clouds and water)

At the very upper row of pixels you should see six pixels having different colours or tones – five pixels at the left (starting with the first pixel in that row) and one pixel at the right side (last pixel in that row).

- First pixel (from left to right): colour and brightness applies to the reflective colour and power on more dark parts of terrain and aircraft
- Second pixel: colour and brightness applies to the reflective colour and power on more bright parts of terrain and aircraft
- Third pixel: colour and brightness applies to the reflective colour and power on more on more dark parts of clouds
- Fourth pixel: colour and brightness applies to the reflective colour and power on more on more bright parts of clouds
- Fifth pixel: colour and brightness applies to the reflective colour and power on more dark parts of water or water shadowing
- Sixth pixel: colour and brightness applies to the reflective colour and power on more bright parts of water

The colour and brightness of the lowest row of pixels is determining how the sky above the horizon is blending to terrain beyond the horizon. I think, to certain degree it also determines the reflective colour and power on terrain just beyond the horizon.

To a certain degree this also applies to the second row of pixels from below. Whereas this also seems to determine how the upper part of atmosphere near the horizon blends to faraway clouds above the horizon.

When giving the lowest two rows of pixels the same brightness and colour (just try a yellowish, reddish or orange coloured grey - concerning sunset colours) so that it fits to the appearance of your terrain textures, you’ll certainly get very smooth transitions between atmosphere and terrain at the horizon.

Haven’t tested sunrise -, daytime – and night textures yet but I think they’ll work the same way.

 

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That’s the sequence they seem to be applied in fs9 – “sky_presunset1” to “sky_postsunset2” for one sunset event, “sky_presunset1_0” to “sky_presunset1_9” for different months or sunset styles, same applies to “sky_presunset2_0” to “sky_presunset2_9” and so on…

Each texture file number, e.g. “sky_presunset1_0” represents one month or two months or one sunset style and blends to “sky_presunset2_0” to “sky_sunset_0” to “sky_postsunset1_0” to “sky_postsunset2_0”. Unfortunately i didn't figure out which number refers to which month.

 

I did a bit of testing of my own, and I believe that the sequence “sky_presunset1_0” to “sky_presunset1_9” is not by month, but rather by day.  Moreover, it does not increment the number by one every day.   Most of the time it seems to jump forward by two numbers each day, but then mixes up the sequence in a way that I haven't yet figured out.  The point of this, obviously, is to generate a completely different looking sky every day, and swap them around in a semi-random manner.

 

What's interesting is how many of the commercial textures overlook this behavior.

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This may be the most clearly stated explanation on the topic I have seen.  I hope you are continuing your explorations - it will be very interesting to see what else is found.

Thanks for all your hard work!

Ron

 

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