Problem with Oahu, Hawaii VT

[smbika]

Hi,

Has anyone else had a problem with the VT contained in the file USA_Oahu_island_L6_10_BM32k.zip which can be downloaded from the Celestia Motherlode site? It is supposed to have an ultra detailed tile of Honolulu (presumably level 10) but when I get up close and personal with it, it becomes a big white square. All the other VTs I have encountered seem to work just fine (for instance, Jestr's 64K England), so I don't think I lack the necessary chops vid- and cpu-wise.

I am running a VAIO P4, 3Ghz, Hyperthread with 512MB RAM and an ATI Radeon 9200 AGP (currently set at 8x) with 128MB RAM.

The version of Celestia is 1.3.2 but the same problem existed in all previous versions supporting VTs.

Thanks,
Sean

[selden]

"It works fine for me".

Have you looked at the DDS surface texture images in the level10 folder on your system to make sure they aren't corrupted?

I use Nvidia's thumbnail viewer (which automatically displays DDS files as small images when using the Windows GUI to look at a folder's contents) and InfranView.



(this links to a larger image)

Note that the city is at a higher resolution than the airport.

[smbika]

Selden,

Thanks for the reply. I have looked at the level 10 images for this VT and there appears to be no image in it corresponding to the image you presented. I will check further with the downloads i have from motherlode (and in the other levels) but i have the feeling it is missing. If it is, can you tell me where you got yours (hopefully not from the motherlode in case they are not in either of the ones they present on that site)?

Thanks,
Sean

[smbika]

Is that i have unzipped them ( there are 3 such files i found) in the wrong sequence:

USA_Oahu_Island_Honolulu_2K_L6-10_BM32k.zip
USA_Oahu_Island_Honolulu_4K_L10_BM32k.zip
USA_Oahu_island_L6_10_BM32k.zip

I am checking the contents of each and will see if there are like-named files which could be the problem.

Thanks,
Sean

[selden]

Sean,

The picture I posted above is a Celestia screenshot, not one of the hires tiles: it shows the southern portions of two adjacent tiles.

The primary level10 Honolulu tile is named tx_126_390.dds

Unfortunately, it's 4096x4096.

I wasn't paying any attention to the order that I extracted the Zip files, all of which were downloaded from the MotherLode just a little while ago.

I'm not certain, but I suspect that the problem is the size of the image (4K), not the order the Addons were extracted. I know that ATI Radeon 9600 cards have a texture buffer of only 2K. I suspect the 9200's buffer is either 1K or 2K.

Usually, Celestia cuts surface texture images that are larger than the texture buffer of the graphics card into smaller pieces so that they'll fit. The resulting pieces still have to be larger than the relevant facet on the 3D spherical model, though. The three adjacent model vertices have to be within the bounds of the partial texture image. My guess is that Celestia can't chop up tiles at level10 because level10 already is at the maximum resolution of the model -- and that's why Celestia's VTs only have 11 levels (0-10).

Sorry.

[alphap1us]

Hi Selden,
Does this mean that L10 is the maximum size of a virtual texture, and that it would require a rendering code change to get VT's with a smaller tile size? You mentioned the other day about getting the LandSat 7 data and making it into a VT, but there wouldn't be much point, if it had to be 4K or larger tiles.

Cheers,
Joe

[smbika]

...sigh...

I suspect there are not too many ideal machines out there which can deal with the demands of the program and its accessories.

Sokay, I can't use the ring shadow feature at the same time as the OpenGL vertex program option for rendering which allows my machine to display spec maps.

C'est la vie!

Tradeoffs exist at all levels of existence...

Thanks for the help!
Sean

ps - i am able to reduce the res of the 4k tiles to 2K using the DirectX texture tool - does not look as nice and is a little misaligned but at least the big white square goes away...and besides, Honolulu was not THAT interesting...

Thanks again!

[selden]

Joe,

Yes, a code change would be needed to go past level 10. Most VTs are being provided with image tiles that are 512 pixels on a side. Some VTs have higher resolution images (1-4K) at level 10 than at the other levels. This simulates having more levels, but an image at level 10 which is larger than 1K isn't compatible with all graphics cards. (Some old cards, like the 3dfx Voodoo series, have even smaller buffers.)

An alternative method for displaying small areas at extreme resolutions is to place one or more separate models at appropriate locations on the surface. Again, the usable size of an individual surface texture image would be limited by the user's graphics card and should be 1K or less for widest compatibility. ( A crude example of this is at http://www.lepp.cornell.edu/~seb/celestia/map-plane.html )

[jdou]

Sorry for that.

I have a GeForce 5700 Ultra with 128 Mb RAM (I bougth this one specially for Celestia )

So, I can use and see VT 4kx4k.

In my next VT, I will provide 1k and 2k VT tiles for all people.

I thing we need some levels more (if possible) to take advantage of the very hires pictures downloaded from for example SpaceImaging or DigitalGloble.

jdou

[Guest]

This is why I switched to Jester's 64k texture Since it uses 1k tiles you get 1 extra level of depth.

[jdou]

This is a good idea.

So, the tiles size at level 10 could be divided by 2.

I am going to download Jester's 64 texture.

jdou

[guest jo]

deleted

[smbika]

http://www.celestiamotherlode.net/catal ... oseup.html

look down the page a bit...

Hope this helps,
Sean

[guest jo]

deleted

[jdou]

Hi J?rg,

Try this link

http://www.celestiamotherlode.net/creators/jdou/

jdou

[smbika]

Hi J?rg,

Don't despair - you should read some of MY earlier posts...

Anyway, Jdou's posted link looks good so go for it!

Sean