32k BlueMarble Virtual Earth Texture is now available

[don]

Thanks Selden. That's why you guys are the graphics experts.

I'll just enjoy, and quit asking stupid questions -- er, make that uninformed or uneducated questions.

[chris]

Don,

You can't cut up a compressed image.

You can cut up some compressed images, including ones compressed in DXTn format. DXT-compression splits the image into 4x4 blocks, which are completely independent of one another. So, as long as you're splitting between block boundaries, breaking up the image into tiles is very straightforward. This is in fact what Celestia does when loading normal DDS textures which are too large for hardware (e.g. an 8k x 4k texture will be split into two 4k x 4k textures on GeForce and Radeon cards.)

--Chris

[wcomer]

don,

I don't know how to split them via chris's method. I think that would require building my own image processing tool. However, I think it may be possible by doing the following (maybe chris could pipe in on the whether or not this would work.)

1) donwnscale the 2x21kx21k tiles to 2x16kx16k, 2x8kx8k, 2x4kx4k, ..., 2x512x512 .tga images.
2) -dxt1c compress both 16k16k .tga to .dds
3) uncompress both the 16kx16k .dss to .tga.
4) dice both the 16kx16k .tga into 1024x512x512 .tga's
5) -dxt1c compress the 1024x512x512 .tga's to .dds
6) repeat steps 2-5 for the 2x8kx8k, 2x4kx4k, ..., 2x1kx1k .tga's.
7) repeat step 2 for the 2x512x512 .tga's.
take the level5 tiles on both side of the prime meridian. Uncompress them. Built 32x1kx512 blocks. Compress and Uncompress these. Split these 32x1kx512 into 64x512x512 level5 tiles.

That should fix all the seams... maybe.

-Walton

[don]

I don't know how to split them via chris's method. I think that would require building my own image processing tool. However, I think it may be possible by doing the following (maybe chris could pipe in on the whether or not this would work.)

Hi Walton,

Wow, looks like you've been wearing your thinking cap!

Hope this, or what Chris is talking about, will work. Good luck testing!

-Don G.

[Harry]

Don, The seams are normal and due to mismatches between the -dxt1c compression of adjacent tiles. I don't know of any compression formats that filter the edges so as to assure proper matching. Probably the only solution is to use a lossless compression like .png or to use -u888 dxt format.

At least on my system (GF 2MX/Linux) this is not due to tile-compression, but probably due to texture-filtering. See the result with lossless compression (PNG) (inset shows the two tiles joined with a graphics program):

[don]

At least on my system (GF 2MX/Linux) this is not due to tile-compression, but probably due to texture-filtering.

Hmmmm, very interesting.

[wcomer]

Harry,

Did you build the .png's from the original Bluemarble Texture, or from the .dds's?

-Walton

[Don. Edwards]

I ran into the same problem when I compressed my 16k Realistic Earth texture. Right down the middle of the 16k .dds is a very slight mismatch between the halves. It is not present in the master texture but only in the .dds. But it is really only visible if you really zoom in close. Were talking down below the normal viewing level were almost everything get blurry anyway. I can only surmise that the textures two halves are being compressed separately and then being reassembled into one big .dds. This is only of my concerns on my 32k texture. I now that there are going to be some mismatches. That’s one of the reasons I am looking for help to break this thing down into tiles that won't show these misalignments I hope.

Don. Edwards

[Harry]

Did you build the .png's from the original Bluemarble Texture, [...]?

Yes, they should match the BM-Tiffs exactly (except for being scaled down to 32k). The inset is taken from the tiles themselves, showing no seam at all, so the seam must have been introduced by the texturing in 3d.

(edit: made "yes" non-ambigous)

[wcomer]

Yes, they should match the BM-Tiffs exactly (except for being scaled down to 32k). The inset is taken from the tiles themselves, showing no seam at all, so the seam must have been introduced by the texturing in 3d.

Great work, Harry! Does anyone know if chris is aware of this bug?

[Harry]

Does anyone know if chris is aware of this bug?

Hmm, is this really a bug (in celestia), or just a general problem of OpenGL-Texturing? My "theory" is that enlarged textures are smoothed only within a single texture, so pixels on the border don't match their neighbours in another texture-tile (see for example the ice of the volcano - the last line of bright pixels is on one tile, the green, darker pixels on the other, so there is a sharp edge because the difference is not smoothed as it would be if all pixels were within one tile (hope it is clear what I want to say

But this is only a theory, if someone with solid knowledge about this could comment on this...

Luckily this problem only appears when extremely close to the surface, so IMHO this shouldn't be a serious issue.

[Guest]

Can you pleas split the level 5 zip file into 2, 3, or maby even 4 files?
My computer cont even download to the halfway point without re-booting

Thank you for a grate textur , I hope to be downloading level 5 soon!

[Florent]

Hi all

I'm new to Celestia, and I've successfully installed some textures in solarsys.ssc... .but this package is strange for me

I unzipped the zip in the right directory (I think...), so now I have :

C:\Program Files\Celestia\extras\BlueMarble DDS
wich contains :

textures directory
BlueMarble DDS.ssc
Readme

Is it correct ? I thnik this is the first thing I have to check...


Then, if it's ocrrect, when I try this, like mentioned in the readme :

How to see the virtual texture:
-> Run celestia.
-> Right click Earth on Earth.
-> Select Alternate Surfaces.
-> Select BlueMarble DDS.

The 3rd step doesn't work at all... I right click on the eart, but the menu wich appears dosen't contain an option to select alternate suface...

So, please help !!!!!

[granthutchison]

Which version of Celestia are you running?

Grant

[Florent]

oops !!!!!

1.3.0, the latest stable release...

I didn't saw that I need a beta version to use it...

Thanks a lot and sorry for the stupid question

[Florent]

Me again... (I'll register soon, to be able to edit my posts...)

is it the latest beta ?
http://63.224.48.65/celestia/files/cele ... 1pre11.exe

12 Mo

"pre11" ?

thx again

[ElPelado]

yes thats the last one.

[Florent]

Thanx again and again !!!

It works great !!!!

I really like Celestia and my chlidren like it too )

go on this way !!

[Star Lion]

The level 5 textur is down, when I try to download it my computer reboots, just like that guest, can you pleas split that zip file into 2, or 4 parts, then it will be easer to download

thank you

[Harry]

when I try to download it my computer reboots

If your download is unreliable, you should use a download-manager capable of resuming downloads. And you should check your system, as there must be something wrong with it if it reboots without reason (if you are running an unpatched Windows XP or 2k, you may suffer from the msblaster-worm - but then there should be a 60sec-countdown before reboot).