Celestia Forums

Okay, Perhaps you guys know that VT cloud textures won't cast shadows, and I want t make an 8k cloud texture by combining the 32k vt by Harald Schmidt. I try photoshop but the alpha channel (the transparent image) is gone, so the image is solid white! So, I just wanna ask if somebody know a good yet free converter or maybe a picture editor.

To lazy to search myself on the internet..

One way to do it is to convert the dds images to png, concatenate the png images and then convert the final png image back to dds if you want; or leave it as PNG, although that's slower to load. Irfanview can be used to do the conversion. It maintains the Alpha channel.

I suspect there are more efficient methods.

I remember Don Edwards made a terrific hires dds cloud texture... that may be the one to use, although I don't recall the file name.

DDS format is not at all annoying...

First off, you should use proper tools that give you optimized DXT-compression quality. Second you should use the correct DXT format for compressing with transparency.

1) Use the DDS texture tools from the NVIDIA Developer site. The new ones are even better in quality and the DDS results can't anymore be distinguished visually from lossless PNG format.

http://developer.nvidia.com/object/nv_t ... tools.html

2) Use the specialized WTV viewer from the same site rather than some mentioned tools that don't even tell the user what DXT format they are supporting. In WTV you can switch on/off the alpha channel, of course.

3) You probably compressed with DXT1 format before. That's what IrfanView, ImageMagic or XnView used to offer exclusively (without. telling). Take DXT3 format instead and you will be fine. Best is to first make your texture in lossless PNG format with GIMP and then compress it to DXT3 with the NV tools.

4) About 8 years ago, I published my first (2k) cloud texture for Celestia in this department and on my Texture Foundry. It was used by thousands of users and is still used by me

Fridger

Wow, i dunno what to say... I've downloaded irvanview, WTV, and nvidia dds utilities... I'll try both way selden and Fridger says.. thanks
I guess this will be a looong time exporting dds to png....

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john Van Vliet wrote:on this i do differ in opinion about "dds"
dds is 100% absolutely great in fast past FPS games
it was meant for use in fast paste games and works GREAT in them

but celestia is a S.....L.....O.....W..........P.....A.....S.....T.....E "game "/sim

Sorry John,

I simply dare to claim that I have way more experience with DXT format. I am not talking about opinions. Rather, I am ready to demonstrate any time the enormous advantage of high-quality Celestia tiles in DDS format. If the great advantage of good quality DDS format would not have been so convincing, I had never spent the time to code direct DXT output for my F-TexTools


The amazing display smoothness of large VT-based textures for Celestia comes from a combination of hardware supported superfast DDS decoding along with good hard drive performance. Since in case of VT's always a number of neighboring tiles is loaded (and decoded), an efficient GPU supported format is hard to beat! In case of rotating bodies, for example, Celestia is certainly NOT a slow paste sim.

Fridger

Since John usually is interested in the highest quality images, I'm guessing that he might have forgotten that DDS has lossless formats in addition to the lossy formats that are familiar to most people.

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heh, people sure likes to promote their 'products' . i'll try the cloud.

if you are interested there is a 16k cloud VT in the celestia motherload FTP folder that i uploaded a few days ago
and should be posted soon
or here:
EarthClouds.L0123.zip
http://www.zshare.net/download/8130014481260571/

I guess the L0123.zip is broken.... the file is only 14MB, not 76MB (I've repeated the download 3 times and no luck). my winrar nor 7zip can't open it..

--- edit ---

Whoa, that's weird, I've tried it once more and it works ... The texture looks nice... Good work John.

t00fri wrote:4) About 8 years ago, I published my first (2k) cloud texture for Celestia in this department and on my Texture Foundry. It was used by thousands of users and is still used by me

Fridger

Sorry for this self-quotation... Anyway, I just found out that my old 2k clouds are also recommended in the Wikipedia page about global clouds in NASA's WorldWind

http://worldwindcentral.com/wiki/Global ... _clouds%29

Fridger