A couple of weeks ago I was planning on releasing a demo texture of what the new 16k Earth texture and the new Northern Summer cloudmap would look like together. My intention was to simply give everyone that wanted to, a way of seeing what the coloring and cloudmap would like. This is what I originally came up with.
I then took a specmap of the same size and added a reversed version of my cloudmap and then layered that on top and came up with this.
I then used the old trick of plugging in the specmap into the alpha channel. That way all anyone would have to do was simply plug in the texture all by itself and you would get specular reflections only on the water. But when I went and tested the texture I saw something that allot of us have been waiting for in Celestia for along time now. The clouds had shadows but only over the water. Well this got me thinking and I started to create a bunch of different specmaps in and attempt to make this possibly work better and of course the test texture never got released.
The end result was quite startling and amazing. Have a look at what Celestia would like with real drop shadows under the cloudmap.
In these pictures the results are of course subtle but they are really there. Here are the same shots with the clouds turned off.
As everyone can see there are cloud shadows on the water. Of course this is very, very far from perfect. You don't get any cloud shadows over the land unless you use a specmap with no continents. But it gave me the initial idea of just how close Celestia really is to being able to implement this feature. As I see it there are two ways it can work.
1. A second specmap with the clouds only that does not interfere somehow with the main specmap. As far as I can see this isn't the best way of doing it. Although this was the way I found out it worked.
2. The better choice would be to have a second cloud layer entry that can be set to zero height so that it appears under the main cloudmap. This probably could be done and I understand some users have had multiple cloud layers work in the past. I do not remember how it was done. But if Chris could just tweak the code a little more we can finally have those shadows under the clouds that they have in Star Strider and Orbiter.
Don. Edwards
P.S.
If anyone wants to try this out themselves they can click on the above texture samples and get the 2k demo texture and specmap respectively and give it try. It will not be very pretty at that resolution but it will give you the main feel of what I saw the first time I tried it. It is kind of shocking to see those drop shadows on the water. But it does make things a little more interesting.
