Celestia Now Has Pseudo-Cloud Shadows!!!!!!!!

[Don. Edwards]

I figured it out.
This has been bugging me for a week now but I finally got it.
I used the Alternate surface overlay texture feature and here are the results.



I still need a few days to get the drop-shadow texture perfected but as soon as it is ready I will post everything you will need to use it. Whats nice is you will be able to toggle it on and off using the alternate texture option.
I am going to bed now that I have this out of the way. Check here tomorrow if anyone wants to know more.

Don. Edwards

[AuReality]

I figured it out.
This has been bugging me for a week now but I finally got it.
I used the Alternate surface overlay texture feature and here are the results.



I still need a few days to get the drop-shadow texture perfected but as soon as it is ready I will post everything you will need to use it. Whats nice is you will be able to toggle it on and off using the alternate texture option.
I am going to bed now that I have this out of the way. Check here tomorrow if anyone wants to know more.

Don. Edwards

Cool!
Can't wait for the release...

Paul

[Darkmiss]

This sounds lik egreat news Don.

But here's my question:
Does this mean that the clouds would have to be static
whatever texture size you use ?

I do like your working 8k clouds, but I like the cloud movement more

If so ill have to wait until Chris can impliment this like the ring shadows.

[Rassilon]

Very nice Don but I am guessing you would have to turn off cloud movement for this to work effectively? or can alternate textures be moved as well?

[Don. Edwards]

No you only have to set the clouds to static mode for the alternate version. Your original Earth settings can remain unchanged. You will simply loose cloud movement when you activate the cloud shadow alternate texture. This is the only way to do this until Chris can give us a working second movable cloud layer.
It is great for a nice ooh-aah effect or when you want to take some screen captures with a little more detail than normal.
No one has to use this at all. I just wanted to get it working and it does. It will be up to each Celestia user as to whether they want to use the effect or not. It is the same thing with the 8k clouds. Either you choose to have high resolution static clouds or lower resolution moving clouds.

Don. Edwards

[Don. Edwards]

Ok this will be the last post with pictures. There already seems to be a pooling of uses into 2 camps. Those that must have the clouds move and those that would rather have higher resolution clouds and cloud shadows.
So if the following pictures don't convince anyone than that’s fine. There are 12 shots in all covering 6 locations on Earth with the cloud shadows turned on and off on the fly so everyone can see what the difference really are.
Larger images can be seen by clicking the thumb-nails images.
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As can plainly be seen there is a very big difference. I can't believe we have lived without this feature this long. All of Celestia's contemporary programs/competition have this feature already. Celestia is falling behind. This little trick with the Alternate Texture is only going to work for a while.
Chris are you hearing this.

Don. Edwards

BTW,
All pictures are with the new 16k Earth texture, the Earth VT specmap, my 8k normalmap, new 8k cloudmap, and 8k cloudshadowmap.

[Buzz]

Don, you are the best!

[Rassilon]

Chris mentioned he was going to be putting in cloud shadows and bumpmaps in one of the next releases...I am hoping when he does its not an overlay like eclipse shadows and ring shadows...There is a high volume of polygon artifacts when viewed up close...the shadow overlay appears to 'break apart' when viewed on the surface...or upon approach to the planet...This however is not a bug in Celestia but in the openGL libraries themselves as I had the same issues in 3d studio max and VRML rendered models using multiple layered meshes...one being the surface, the other being a transparent cloud layer...In this case the mesh broke apart with a striping effect and eventually disappeared...A sort of culling effect that could be fixed by camera perspective only...of which perspective was on a larger scale...leaving the planets made appear small and unrealistic...

[Vicware]

BTW,
All pictures are with the new 16k Earth texture, the Earth VT specmap, my 8k normalmap, new 8k cloudmap, and 8k cloudshadowmap...


I've lost track which texture is which at this point. When you say "new"
16k Earth texture, which one are you referring to (link?) Along with
specmap, normalmap and cloudmap.

Thanks - Vic

[Don. Edwards]

Vicware,
You must not have seen the post in the Textures section.

Click the picture to go to Earth Central 3

Seasons Greetings and Merry Christmas to everyone.
Well it ended up two days late but here it is. My much needed update to Earth Central.
So what are you going to find here this time around. For starters the updated 16k Earth texture. It is not perfect but I think it’s better than the last one. There may be a few things a little off with it and if its idiosyncrasies are to many than I can always go back and fix it. I will not give away what they are so you will just have to look for them. There are not many of them luckily. Of course it is also available in smaller resolutions.

The next is that I have the new Northern Summer-Southern Winter Static 8K cloudmap ready for download. To use it you will need to go into your solarsys.ssc file and set Earth's cloud speed to 00. This will lock the clouds to where they are supposed to be in relation to the surface. It also allows your video card to render the cloudmap at its highest level. The 8k cloudmap will not render properly if you do not shut down the cloud spinning. I also have lower resolution versions you can use with the clouds in motion as before. But you will only have 1/4 of the detail and you will have storms moving over areas that they just don't move in the real world. So the choice as to which you use is completely up to you. I personally do not miss the clouds moving that much. It is much more interesting seeing all the details instead.
The Northern Summer-Southern Winter Static 8K cloudmap was based on BlueMarbles 8k cloudmap. This cloudmap was of a more Northern summer weather pattern to begin with. There are some tropical storms here and there. So I decided to add to the texture. So I went through many of the pictures of typhoons, hurricanes, and cyclones on the BlueMarble site and chose the ones that had what I felt were the best features. I then desaturated the color; adjusted brightness and contrast to match the 8k cloud map and located the proper places for the storms to go. Then it was a simple task of pasting in as layers and doing some nice blending into the background texture. After this was done I used the time tested way of using Gimp to create a transparent cloudmap. The rest of my process is very complex and you might call my trade secret. I did learn a few of these tricks from Fridger so I have to give him some credit here.

I think that the cloudmap can and will speak for itself. I hope everyone enjoys it.

Now there is more. I also have put up another rebuild of my Night-lights & Auroras texture. It is available in several resolutions and formats so everyone can play with this and let me know what you think.

Lastly I updated the site with a link to the Earth 18000BCE texture.
So that should wrap up the biggest update to Earth Central to this date.
I am considering doing some revamping of the whole Celestia Hub concept. I do not have my own textures for all the planets in our solar system and I do not plan on making one for all of them. But what I might do is contact other texture artists and see if they would like me to mirror there work in the wholes that need filling. That way the hub can look more complete and it will be another resource for downloads of some really nice textures that at times are not available.
As always I welcome input either positive or negative. And of course I always take what ideas are given very seriously. Also if you have any ideas for the Celestia Hub don't be afraid to contact me either by PM, email, or a post here in the forum with your ideas and input.
Hope this makes this Christmas for all Celestia users a happy one.

Don. Edwards

Hey Rass,
As far as I can tell my shadows do not break up. They aren't rendered like the ring or eclipse shadows. They are an actual texture layer that is applied over the main texture. I am using both the Alternate Texture feature along with the Limit Of Knowledge code to do it. As the this means you have to plug-in a cloudshadowmap to get the effect. I am sure Chris could resort to this method as well but to plug it into the cloud section of the code. That way those who wanted animated/moving clouds could have both the clouds moving and the shadows as well. I have experimented now with cloudshadowmaps of 8k, 4k, and 2k. 4k being the limit if you want the shadows to match an 8k or 4k cloudmap. I will try and have an example of my solarsys.ssc up for everyone to see either tonight or tomorrow night.

Don. Edwards

[galileo]

that is damn sexy. fantastic work!

[Rassilon]

Hey Don,

If chris does indeed use this alternate texture method for all shadows he might fix the current artifact problem shadow casting has in Celestia...but it may break up once its animated, I dont know...The current style is a overlay of another texture I believe, but its elevated a slight bit...Alternate textures seem to appear to be a part of the surface texture.

Ive tried this before applying to the surface, shadows...Not much different but does have that nice effect of realistic cloud shadows...The only difference is you can disable the shadows with your method...

For those who do not care about animated clouds it is a wonderous find...For ones like me who love to see clouds flying across the landscape...its a bit of a sacrifice...

[granthutchison]

One drawback to using the alternate texture approach (and I say this without in any way intending to criticize Don's splendid inspiration), is that the cloud shadows are not properly projected on to the underlying surface - so near the terminator, where we should see long cloud shadows stretching towards darkness, the shadows are still precisely under each cloud. I can't think of a way that alternate textures could be used to model this dynamically, with cloud shadows shifting from one side of the cloud to the other as the clouds move from morning to evening.

Grant

[Don. Edwards]

Grant,
This is not as big a problem as you think. The shadows do apear only on one side at a time and there is a little distortion of the shadows because they are drawn on the surface not above the suface like th clouds. If you set you clouds to a slightly higher altitude it even makes the shadow depth and offset all more present. I will hopefully be uploading the cloudshadowmap tonight with the info for everyone's solarsys.ssc. Then everyone can try it out and see what they think.
Hey it is the best that can be done until Chris can implement cloudshadows in another way.

Don. Edwards

[abramson]

I will post everything you will need to use it.

Greetings, Don. Did I miss anything, or you didn't explain what to do to achieve these cloud shadows? I would like to experiment.

Cheers,

Guillermo

[Don. Edwards]

Sorry for not getting the flies and instructions up everyone. I have been down with the stomach flu the couple of days and not quite up to sitting at the computer. Also the cloudshadowmaps are too big to upload by my modem. So I will try and see if I can get them uploaded tonight from my brothers if I am feeling up to it. If not it will be Friday night.

Don. Edwards

[Don. Edwards]

Ok, I am done with the Pseudo-Cloudshadows for now. I am making a new Northern Winter Cloudmap and it will most likely include the Shadowmaps with it when it is finished.
I have uploaded the 8k and 4k CloudShadowMaps and am ready to share my info. They are in the .DDS format only. This is because of memory issues on some video cards. Now there are some limitations to using this little trick. The first being that you will have to use either my new Northern Summer-Southern Winter cloudmap at 8k or 4k. The second is that you have to lock the clouds in place for this work right. So you need to go into your solarsys.ssc and set your cloud speed to "0". Then just below The entry for Earth's Albedo setting you need to add the following lines.

Albedo 0.30
}

AltSurface "Cloud Shadows" "Sol/Earth"
{
Texture "Earth.*"
OverlayTexture "8k-CloudShadowMap.dds"
NightTexture "NightLight.*"
SpecularTexture "earth-spec.*"
Color [ 0.85 0.85 1.0 ]
SpecularColor [ 0.5 0.5 0.55 ]
SpecularPower 25.0
HazeColor [ 1 1 1 ]
HazeDensity 0.36
Radius 6378.140 # equatorial
# Oblateness 0.0034

BumpMap "Earth-Bump.*"
# BumpHeight 4.5
}


"Moon" "Sol/Earth"

I left the entries for Albedo and the Moon in simply as place holders so do not include those lines in your solarsys.ssc. Also each entry of the Alternate surface entry needs your settings for your normal Earth entries.
So in Texture "Earth.*" place the name of the Earth texture you are using. Do the same for the NightTexture, SpecularTexture, and Bumpmap. The important line is OverlayTexture. This is were you need to plug-in the name of the cloudshadowmap you choose to use either it be the 4k or 8k version. I recommend using the 8k version with the 8k cloudmap if you have the resources. If not than you can use the 4k shadowmap with the 8k cloudmap and it still looks ok but there is a little loss in detail in the shadow boarders. Of course if you video card is somewhat limited than you will need to use 4k cloud and 4k shadowmaps.
I have as yet not had a chance to test this on any video card with less 128MB of VRAM so I can't be sure how well it will work on 64MB cards and lower. But it should work to some degree. A 64MB card can render my 8k clouds in static mode so the cloudshadowmap at the 4k level should work with as well.

When you have all the entries entered and saved, start Celestia and navigate to Earth. Right click on the Earth and you should see an entry under Alternate Texture called Cloud Shadows. Just select that and watch the shadows appear under your clouds. If the effect isn't strong enough you can go back into your solarsys.ssc and adjust your cloud texture height to 11 or 12. This will put some added distance between the clouds and the shadows and make them more apparent.
Also Grant brought up the issue that the shadows would not be dynamic and they wouldn't shift. Well that is partially true. When you are close to the terminator the cloud shadows will not be stretching like they would in reality. But other things do kind of work, such as if you are viewing a cloud from directly above there is no shadow. If you shift perspective to one side or the other the shadow will start to become more apparent the more you move from above it. So in that sense they do work like real cloud shadows. One final note on the cloudshadowmaps. They are not black but a very dark grey and they are semi-transparent like real shadows. I took the transparency as far as I could before the effect was lost to make them as real looking as possible.

I hope you enjoy trying this pseudo-feature out. No one has to use it if they don't want to. I was just playing around when I discovered this could be done. I know that there are those of you that feel the Earth's clouds need to move and that’s fine so this little trick is not going to be for you or make you happy I guess. This is more for those that would like to have a little more accurate look to there planet Earth with the clouds being were they are supposed to be and having the look and feel shadows and depth to the atmosphere. Here are the links to the shadowmaps.
4k CloudShadowMap http://63.224.48.65/~impulse/Earth_Cent ... dowMap.zip
8k CloudShadowMap http://63.224.48.65/~impulse/Earth_Cent ... dowMap.zip

Don. Edwards

[DJ_Night]

Thanks Mr. Edwards and Merry Christmas!, it looks and runs great, even on a 32MB GF2...

Earth_Clouds_8k.dds & Earth_Clouds_Shadow_8k.dds ...

I?ve tested it on GF2MX 32Mb, 64mb, Ti4200 128mb, runs smooth 10-20fps..

32k VT BM, 32k VT NormalMap, your 8k NightMap and clouds & shadow map.

its just a matter of AGP texturing and Page/swapfile..



Hopefully a day will come when Celestia will support multiple colud layers,

keep up the good work.





(8k Shadow Overlay Texture)



(8k shadow Overlay Texture & 8k Static Cloud Texture)

[abramson]

Hi, everybody.

Don, it's beautiful. It works fine with my Intel 845GVAD and no graphics card (graphics provided by 64MB by the motherboard, 1GB total RAM), which does not give me bumpmapping nor specular reflexions . Anyway, I have observed that the overlayed shadows *dissapear* when the height above the Earth is less than about 71 km. Has anyone else seen this? Might it be a "feature" of my graphics "card"?

Greetings, and my best wishes to everybody for 2004.

Guillermo

[ElPelado]

I would like to try the 4k shadows, but i cant find the file in the link posted here. Does anybody still have it?