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Outerra Tech Demo download. Help with graphics driver issues

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Author Topic: Snow  (Read 17619 times)

cameni

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Snow
« on: July 20, 2010, 08:08:24 am »

Just a quick and dirty hack to the terrain material system to make it like there was a snow on the mountains.

The snow covers the surface if it is flatter than a critical slope, whereas the critical slope depends also on the elevation. This way the transition to lower altitudes looks better, although it still needs some tuning.




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corona

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Snow
« Reply #1 on: July 20, 2010, 08:36:51 am »

Wow, just awesome.

However, they all look very..."hazy". Was it just a hazy day or is there something else going on? Also, does snow have depths? Not sure how to explain what I mean.
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petitfilou

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Snow
« Reply #2 on: July 20, 2010, 08:50:49 am »

Works really well for a 'dirty' hack. ;)

Will it be possible to have the truck leave tracks in the snow?  like the dirt tracks effect, carved into the terrain.

I can't imagine how this engine will look once all components are put into place, together.  Quite amazing.
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cameni

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Snow
« Reply #3 on: July 20, 2010, 10:23:53 am »

Quote from: corona
They all look very..."hazy". Was it just a hazy day or is there something else going on? Also, does snow have depths? Not sure how to explain what I mean.
Hazy .. weird, people always said we have it too clear. But I've been adjusting some atmospheric parameters recently, so maybe that causes it. It also depends on altitude and time of day.

Here, two screen shots with markings of what's visible, this one from 7,000m (~23,000ft):


This one from 20,000m (65,617ft):


Snow currently does not have depth, but it will be possible, also with vehicles leaving temporary tracks.
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corona

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Snow
« Reply #4 on: July 20, 2010, 10:47:52 am »

I don't mean the far away stuff, that looks fine. I guess a better way to put it is, the forground is too hazy in relationship to the background IMO.

So for instance in this picture:
http://www.outerra.com/shots/k298.jpg
In this shot the foreground is .... I dont know what it is, but my first thought was that it was haze.
Perhaps its the shadows and its just a misfortunate shot. But here...

 http://www.outerra.com/shots/k299.jpg
The Peak in the forground (best seen on the right portion) already seems to be .... well hazed....like there is a semitransparent layer on top of it. Yet the mountain looks to be very near, so haze would only be seen if there was real fog or a very hazy day. But if that were the case, then the background should be completely invisible. The fading/hazing out of the mountains in the background looks absolutely fantastic. This is all just my personal optinion of course.

Again, thnx for posting these, loving it!
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cameni

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Snow
« Reply #5 on: July 20, 2010, 10:58:39 am »

I see what you mean. I'd say it's the effect of morning light then, sun is quite low there.

But also the atmosphere isn't perfect and I will be reworking it to get better results (there are some cases where it's not that good currently), so we'll see then.
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RaikoRaufoss

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Snow
« Reply #6 on: July 20, 2010, 11:17:00 am »

Looks really good for an improvised solution!  How much longer before we get a dedicated solution for snow?
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MatthewS

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Snow
« Reply #7 on: July 20, 2010, 06:04:12 pm »

Snow looks very very good!   Your screen shots just go to show how outdated FSX is!

Love the way the snow doesn't cling to slopes that are too steep. Would you expect to see more snow coverage on steeper slopes if the snow layer was thicker?

In FSX snow is either on or off.  But maybe Outerra could generate variable levels snow coverage?  Thinking of spring where the snow is almost melted compared to winter.

Also, will snow show on the tree foliage?
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MatthewS

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Snow
« Reply #8 on: July 20, 2010, 06:20:37 pm »

Also, what actually triggers snow?  

I'm guessing it will be based on temperature and humidity?  

So in a desert on a cloudless but freezing night there will not be snow because very low humidty?

I guess a "weather engine" would be feeding Outerra that information.   How the weather engine gets its info is not important I guess, to Outerra its just a black box.  And that would allow plug-in to supply Outerra with more accurate info (eg info based on metar downloads, table based regional season/temp/humidity lookups etc).
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cameni

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Snow
« Reply #9 on: July 20, 2010, 06:36:46 pm »

Well everything is tunable. The condition for snow is currently this: at altitude 4500m snow holds on anything below slope 0.9 (in range 0..1, flat to steepest), and at the altitude of 3000m on anything flatter than 0.0 - that means it ceases to appear even on flat surfaces (this is simplified a bit, there's also a factor of terrain curvature). Anything in between uses an interpolated value of critical slope.

Now this sounds like a made up rule, and it is. It's not that far off, actually. The ability of snow holding on to the slopes relates to the temperature, which falls with rising altitude.

Currently it's just a hack because it doesn't take into account the actual climate - average temperature and precipitation - and the season. But even if we just computed the approximate surface temperature using latitude, day of year and altitude, the result would look rather good - you'd get permanent snow in arctic areas, the snow line would be lower in mountains that are closer to the poles, and it will change with the season because sun rays fall more vertically. Actually, a very easy thing to do.

The final solution has to include average precipitation data, though. For example the Tibetan plateau will have less snow then, even though the temperature is low due to the altitude.

A weather engine would be probably only feeding the information if it is snowing right now; whether the snow stays on the ground is another thing, and that can be driven by the above mentioned model, maybe augmented by some snow level reports.
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cameni

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Snow
« Reply #10 on: July 20, 2010, 06:48:51 pm »

Quote from: MatthewS
Also, will snow show on the tree foliage?
There should be a different model for tree covered with snow, but it will be probably generated automatically later.
Then those trees standing in an area where the ground was computed to be covered with snow will be rendered using the second model.
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MatthewS

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Snow
« Reply #11 on: July 20, 2010, 07:12:34 pm »

Quote from: cameni
Well everything is tunable

Yes!!!  

Please expose all these tunable parameters in an XML config file (Outerra.Config?) so that users can tweak the default settings.

On start-up, if Outerra discovers the .Config file is missing it could regenerate the default .Config file.

You will make people ("hardcore" users) very happy if you allow such tweaking!
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Abc94

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Snow
« Reply #12 on: July 20, 2010, 09:16:45 pm »

Wow, the snow looks great!

You should post a high resolution screenshot that can be used as a desktop background!  :D

EDIT:  Is it ok if I use some of these images as a spray in some source engine games such as Team Fortress 2?
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cameni

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Snow
« Reply #13 on: July 21, 2010, 02:10:29 pm »

Quote from: Abc94
Is it ok if I use some of these images as a spray in some source engine games such as Team Fortress 2?
Sure, no problem.

And what does it mean to use them as a "spray"? :D
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Abc94

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Snow
« Reply #14 on: July 21, 2010, 02:27:34 pm »

Quote from: Cameni
And what does it mean to use them as a "spray"?

It's just an image that you can place or "spray" on a wall or any surface while playing source games like Counter Strike that other people can see as they walk by.

I just wanted to make sure it was ok as it is kind of a way to promote Outerra (although I highly dought it will have any effect).
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