[LOW] Sunlight at night

[SkulkrinBait]

"the light of the sun is dazzling on the white slopes of the mountains"

This description occurs at night.

Not a big issue, but I'm sure some pedants won't approve! ;D

[Ringthane]

Crime and Punishment is a lot better...

[Matija]

Natmus said:

They don't, but only if they are uninformed pedants

Even if darkness has falled on the lower ground where the observer stand, it could very well be that the sun still shines on the tops of the mountains, as it is only below the horizon of the observer. After all, it's just after nightfall for the observer, isn't it?

During high summer here in Denmark where I live, even if Denmark is located well to the south of the Polar Circle, the sun below the horizon can light highlying clouds during all the night, which is an impressive spectacle. I believe Muscovites, which live about just a far south as Danes, calls it White Nights.

But that aside. Depending on the height of the mountains and the position of the sun below the horizon, the above scenario isn't at all unrealistic.

But such a light can hardly be called dazzling, don't you think?

But maybe the light of the sun should be changed to light of the full moon, when it's night.

Or, to avoid changing the code, the light of celestial bodies of a very high magnitude?

[sparrowhawk]

I think that the bug has been raised before (by Chris? Can't remember).

I plan to move the "ambient text" to a table (at the moment it's hard coded into a script). In a table, it will be easier to make it data driven and falg whether a message can display at night, day, or both.

But very low priority. For the moment, I'll stick with Mads' explanation!

[Matija]

Yes, it was rised before.

[Ringthane]

"There is a high density of EMR inside the visible range due to albedo and direct emission from celestial bodies" ;D

[Matija]

The angle under wich the observer looks at the snow on the mountain, must be the same as the angle under wich sunrays are falling on the snow, to percieve it directly, and thus be dazzled by it (as with a mirror). If he stands on low grund, then the sun must be high in the sky for the effect to take place. Ohtherwise, he only sees sunlit mountaintops, without the dazzling effect, as is the case on mornings and evenings.

But why do you think the observer stands on low ground in the first place? The message only appears when the subject is walking ON the mountains?

[Ringthane]

What if they sold ray-bans in Midnight? And ski masks? Nothing would be dazzling... man, that's it, I found my new millionaire industry. Shades of Midnight, Inc. ;D

(Snell rules, by the way)

(I mean, that's not meant as in "the rules of Snell", but rather that Snell himself ruled)

(I mean...)

[SkulkrinBait]

It's Midnight, not Earth so I can think of any number of explanations for this "bug".

;D

Don't want to make more work for JY expecially when there are far more worthy things he could be doing.....

[Ringthane]

Okay, maybe not ski masks, but the sunglass thing has a golden road ahead of it!

[Natmus]

Matija said:

The angle under wich the observer looks at the snow on the mountain, must be the same as the angle under wich sunrays are falling on the snow, to percieve it directly, and thus be dazzled by it (as with a mirror). If he stands on low grund, then the sun must be high in the sky for the effect to take place. Ohtherwise, he only sees sunlit mountaintops, without the dazzling effect, as is the case on mornings and evenings.

Wrong, for the single reason that snow isn't a single plane mirror. Rather, each snowflake is a tiny mirror in it's own right, and there's billions of them, pointing in every concievable direction. Just once in a while, the random nature of things will let a lot of them reflect the sunlight at the same spot, creating a dazzling effect on the observer in that spot.

But why do you think the observer stands on low ground in the first place? The message only appears when the subject is walking ON the mountains?

In the mountains. As for why the observer would stand on low ground, I'll give you four irrefutable reasons:

1: The In-Game explanation: When you make a move through (or into, as it please you) a mountain square, you pay the movement cost then, meaning that you don't have to spend any more extra time moving away from the mountain square (unless it's into another mountain square, of course). Therefore the mountain must be crossed, and you are standing on the other side, where it meets the lower ground.

2: The Common Sense explanation: Lords and armies are trying for the least tiresome road, even in mountains, as they are hardly trying to burn as many excess calories as possible for recreationally purposes. So they use passes and valleys to travel in, not the steep mountain sides. It is most likely that the traveller will keep to the low ground as much as possible.

3: The Short explanaition: Even in mountains, that's where you will find a place to rest for the night.

4: The Obvious explanation: Night has just fallen, hasn't it? If it's dark where the observer is, and the sun still lights the mountains tops, the observer obviously isn't on the top of the mountains, is he?

[Ringthane]

Sorry, man, but for every snowflake you have to consider the fractal nature of its geometry, and always apply normal-to-surface reflection, the thing is you apply it, as you say, to multiple planes and on top of it, adding refraction and diffraction also. But the right-angle thing holds. Moreover, the flake is not perfectly flat as it always has, to some degree, a measure of convexity at the centre. This will cause partial trapping of the incoming light, creating the much common "sparkle" effect.

See Koch, Mandelbrot and Serpinski.

[Ringthane]

Did you read me say that either of you was wrong? I am merely correcting a point in your reasoning which is not scientifically consistent.

Mullins-Sekerka instability, now I remembered. The hole thing.

[Ringthane]

I don't like the term empty words. Not empty, here, see this beautiful picture evidencing ref and diff:

[Ringthane]

It could more probably be caused by refraction than reflection, since tangent arcs might appear according to halo formation:




So you guys have been arguing about observer-dependent reflection effects, whereas refraction, occurring in all the possible ways along the quasi-liquid cap of the flakes, is more likely responsible for the dazzling.