Celestia Forums

I am currently using a file named "earth-clouds.png" which is 581kb in size and all white when opened. I tried using "earth-clouds8k.png" but then the earth's surface image gets corrupted for some reason (when opened the las png is not all white, it's white clouds with a black background, so it must have a format different than the one I'm using).
Thing is that for the earth's surface I'm using a hires tex and lores clouds on top look bad.
Does anyone know where to get hires of cluds in the appropiate format?
Thanks

Well I hate to disapoint you but Celestia doesn't give any better definition with cloud textures if there over 2k. This is not to mean you can't use a 8k cloudmap but all you will be doing is burning up video memory that can be used for other textures. Unfortunatly because of your video card choice you are limited to using .png images. At this time any Ati Radeon cards can't use .dds image textures. I will be releasing a very nice bumpmaped cloud texture that is based on Fridger's bumpmaped cloud texture. It is only a 2k .png but the results are quite nice and can be seen in varoius posts in the thread about new earth textures from space-graphic.com. I along with Fridger, Rassilon and many others have played with large cloudmaps and unfotunatly Celestia just can't draw clouds any better with these big textures. So in cloud textures bigger is not better.
I hope this helps.

alegator

If you have photoshop, open earth-clouds.png and apply the drop shadow filter. Colourise a lightish blue. save as earth-clouds2.png and update your ssc file. That should give your clouds more volume.

I cobbled together a 4k cloudmap(Bluemarbles) in gimp and heavily bumpmapped it. It turned out quite well. There may be too much bump mapping for some but i think it looks quite spectacular!http://www.hpphoto.com/servlet/LinkPhoto?GUID=2e7d534b-7dad-73b2-59f1-33e43f7b7069&size=lghttp://www.hpphoto.com/servlet/LinkPhoto?GUID=3a16785b-4d9a-605e-389f-796d3ee25c69&size=lg[img]Check%20out%20the%20altitudes.%20What%20does%20anyone%20else%20think.[/img]

Well you dont seem to be able to link to a full size photo on hpphoto so that size will have to do. If anyone wants a full size i could email it to them.

Here are a few more 'small' samples

Hi every few days i put up a new current clouds that i make from sat. images

they are 4096x2048 in .png I still am having bugs making.dds clouds

Hi nameless, I think your clouds look great. Did you put them on a server somewhere for download?

Nah i dont have a server + am stuck with a 56k modem so it's not really feasible to upload them somewhere. I'll mail you two big pics of them and if you like them i'll let you know how i made them.

except you dont have an e-mail address Here's a snap of Don Edwards clouds that i also heavily bumpmapped. Detail in the clouds shows up much better at higher resolutions when you heavily bump map them. Look out japan!

I do now! I would be very pleased if you would send it/them. If you agree, I could make it available for download.

i sent you some of the above pics in full resolution. feel free to do whatever you want with them.

I should mention that the cloud maps can only be as large as the maximum texture size on your graphics card. They do not get split into multiple textures like surface maps do. On a GeForce3 or GeForce4 (and I think on a Radeon 9700 as well), you can have a 4096x2048 cloud map. On a GeForce2, GeForce4 MX, or Radeon 7000 the max size is 2048x1024. I'm not sure about other graphics cards (but if you have something other than a GeForce or a Radeon, upgrade if possible )

--Chris

chris wrote:... you can have a 4096x2048 cloud map. On a GeForce2, GeForce4 MX, or Radeon 7000 the max size is 2048x1024.

--Chris

The maximum size of a (cloud) map is 4096x4096 (GF3 + 4) or 2048x2048 (GF2, GF4 MX, or Radeon 7000). Celestia report this 'max texture size' in OpenGL Info. Now such a format have vertical and horizontal a different resolution but it dosn't look bad and you will notice the better resolution.

Another thing i have an idea how hires clouds could work in celestia. Is it possible to add a modified planet model witch use the alpha channel for transparency and not for specular reflection ? If this works we could build real bumpmaped hires clouds.

Bye Jens

Aha! that explains why i my 8k cloud map turns the planet into a white ball. I was just about to ask that question in a post-thanks chris.

nameless wrote:Aha! that explains why i my 8k cloud map turns the planet into a white ball. I was just about to ask that question in a post-thanks chris.

That's NOT the reason. Even with my 32MB GF2 GTS card, an 8k cloud texture entered into the /alpha channel/ gives a perfectly nice cloud pattern, except it's very slow. If you want to convert this into dds you need to use DXT3 format NOT DXT1c. The latter gives a white ball. Similarly, if you use the clouds grayscale texture in form of a JPEG or do not put it into the alpha channel.

In conclusion, you did it incorrectly..

Bye Fridger

There's really no point to using an 8k cloud texture on a GF2 GTS. The maximum texture width on that card is 2048. A larger cloud texture will be automatically scaled down to a width of 2048 by the driver, so you're better off just starting out with an 2048x2048 cloud map. It's not a problem with other textures, because they can be split into subtextures. The reason that cloud textures cannot be split is because a texture transform is used to make the cloud layer move, and the texture splitting trick only works with fixed textures.

--Chris

chris wrote: ...is because a texture transform is used to make the cloud layer move...

Is that because you're using linear textures instead of swizzled textures for the clouds? If so, could you use a vertex shader to tweak the texture coordinates of the vertices instead of the "texture transform"?

I'm taking a class on shaders this semester at school, so my knowledge is still very little. Just enough to be dangerous , but it's very interesting stuff. It's being taught by one of the guys on Microsoft's XBox performance team, so it focuses on nVidia hardware (as in the XBox). I'm hoping to delve deeper into Celestia's shader code if I can find some time away from school projects.

- a b i o g e n e s i s -

chris wrote:There's really no point to using an 8k cloud texture on a GF2 GTS. The maximum texture width on that card is 2048. A larger cloud texture will be automatically scaled down to a width of 2048 by the driver, so you're better off just starting out with an 2048x2048 cloud map. It's not a problem with other textures, because they can be split into subtextures. The reason that cloud textures cannot be split is because a texture transform is used to make the cloud layer move, and the texture splitting trick only works with fixed textures.

--Chris

Of course, I am well aware of this, but I just wanted to make clear that the above "white ball" effect was not due to using an 8k clouds texture. For good reasons, my earth-clouds that are used by many have 2k size;-).

Bye Fridger