Help With Transparent Textures

[D.Edwards]

Alright everyone,
Can someone point me to where I can find out how to take a flat black and white tiff image of earths clouds and turn this thing into a tranparnt image I can use with Celestia. I havew tried Photoshop, I tried Gimp which is confusing as all heck to no end. I just don't see how a flat 2d black and white image is tranformed and since no one seems willing to share there own coveted earth clouds png files the rest of us are left to beg for help and answers. Just someone point me to some instructions somewhere please.

[Pixel]

Alright everyone,
Can some point weere I can find out how to take a flat black and white tiff image of earths clouds and turn this thing into a tranparnt image I can use with Celestia. I havew tried Photoshop, I tried Gimp which is confusing as all heck to no end. I just don't see how a flat 2d black and white image is tranformed and since no one seems willing to share there own coveted earth clouds png files the rest of us are left to beg for help and answers. Just someone point me to some instructions somewhere please.

here example how you can create clouds by your own .

1) download http://earthobservatory.nasa.gov/Newsroom/BlueMarble/Images/cloud_combined_2048.tif
2) load it into Gimp
3) with Gimp create new image (2048x1024 grayscale)
4) right click over the image , then select from menu (image-->mode-->compose-->RGBA)
5) select for red,green and blue channels the new(untitled white) image and for Alpha select cloud_combined_2048.tif
6) then save the composed image in TGA format (rclick->file->saveAs)
7) use dos nvdxt tool to convert targa file in dxt3 dds format :
nvdxt clouds2k.tga -dxt3

You can do the same with 4k and 8k clouds from the same site, but save them as png, because dds variants of these don't work in Celestia at least for me.
And once again - the visual difference between 2k and 8k clouds are neglectable.

You also can download the 2000x1000 sat-clouds that are produced every 2h from here http://xplanet.sourceforge.net/, but you should rescale them to 2048x1024 and to save the jpg in single channel-grayscale.

[D.Edwards]

Well I tried your instructions. But for me they are still to vague. I just am not comfortable using Gimp. I am used to the layout and fucntions of Photoshop. I tried this several times and all I get is a big white nothing.I am just going to waite for someone else to do it and I will just download it from them. I use the 2k.dds file and it works. I just wanted to be able to tweak the clouds a little because there are a few iregularities with them and I wanted to clean them up a bit. So unless someone is will to do this for me I am just going to have to waite it out.
Thanks for your help.

[t00fri]

Alright everyone,
Can someone point me to where I can find out how to take a flat black and white tiff image of earths clouds and turn this thing into a tranparnt image I can use with Celestia. I havew tried Photoshop, I tried Gimp which is confusing as all heck to no end. I just don't see how a flat 2d black and white image is tranformed and since no one seems willing to share there own coveted earth clouds png files the rest of us are left to beg for help and answers. Just someone point me to some instructions somewhere please.

I am surprised. The difference between "the rest uf us who are left to beg for help" and those who know e.g. what an Alpha channel is, is very simple: The latter just took half an hour of their time to read carefully in the existing, excellent documentation that includes tutorials etc. But this activity seems more and more to become an unsurmountable barrier;-)

My impression is that is is not GIM P that confuses you in contrast to Photoshop, but rather the "missing half an hour";-). It must have taken you more time altogether to write all the respective emails in this forum...

Last not least, it is also great fun and useful in many respects to understand and then apply these basic concepts of image manipulation.

Bye Fridger

[axel]

well, to me it just seems that some people are willing to help and share everything with everyone and others are trying to teach everyone.

I prefer the first.

Also in the texture department it seems that some admittedly clever guys look angryly down on the normal not-unix user and think: Don't steal our time, you have could invested mine into wisdom and yours reading man-pages.

Understandable, but not prefarable. Chris has always tried to suit everyone as best as he could, a philosophy I *extremely* high respect. This way is the only one to keep everyone happy and supportive. Without this several important features simply wouldn't be existant.

If someone here had been told how to handle the alpha channel in photoshop, he could have done several new textures in the time it takes him to switch to diff. tools. In my eyes the hurdles on the way to support Celestia should be as low as possible.

If I had received the hi-rez textures instead of a 'go, download and combine in n+1 steps on your own and everyone else as well' me and a lot of ppl had already downloaded a new, admittedly extremely well done texture pack and probably had started to participated as well.

Instead a few sceenshots tell everyone 'Look, but don't touch.' Sigh.

I hope you can understand my point,
Axel

[Guest]

well, to me it just seems that some people are willing to help and share everything with everyone and others are trying to teach everyone.

I prefer the first.

Also in the texture department it seems that some admittedly clever guys look angryly down on the normal not-unix user and think: Don't steal our time, you have could invested mine into wisdom and yours reading man-pages.

Understandable, but not prefarable. Chris has always tried to suit everyone as best as he could, a philosophy I *extremely* high respect. This way is the only one to keep everyone happy and supportive. Without this several important features simply wouldn't be existant.

If someone here had been told how to handle the alpha channel in photoshop, he could have done several new textures in the time it takes him to switch to diff. tools. In my eyes the hurdles on the way to support Celestia should be as low as possible.

If I had received the hi-rez textures instead of a 'go, download and combine in n+1 steps on your own and everyone else as well' me and a lot of ppl had already downloaded a new, admittedly extremely well done texture pack and probably had started to participated as well.

Instead a few sceenshots tell everyone 'Look, but don't touch.' Sigh.

I hope you can understand my point, :?
Axel

I definitely do not agree with your point of view, that I can only see as entirely "consumer style". A number of us (besides Chris) are investing a significant amount of time into Celestia entirely for idealistic reasons. I think for people who want to create e.g. cloud textures of extrasolar gas giants, it is simply /much more revealing/ and /not asked too much/, to spend half an hour reading an excellent tutorial and experimenting themselves rather than blindly suck down 200 MB of prefabricated textures.

As I have also explained to you privately, there is a very simple technical reason why these textures are not (yet) generally available.
Did you perhaps spend one minute estimating how high the load on any WEB server would be if a large number of interested people start downloading those textures in 200MB units!? Also Bruckner's site does not seem to be able to handle this.
My site is entirely for professional matters, anyway.
The issue with textures right now is on entirely exploratory terrain. That is why I have always tried to answer peoples respective questions and /motivate/ the fun of own experiments. In due time there will certainly be also an "official" hires set of textures made available at the Celestia site.

Bye Fridger

[t00fri]

If someone here had been told how to handle the alpha channel in photoshop, he could have done several new textures in the time it takes him to switch to diff. tools. In my eyes the hurdles on the way to support Celestia should be as low as possible.

One further word, Axel:
------------------------

I have really given /numerous times/ in this forum step by step instructions on how to use the Alpha channel, what it is etc.

I am normally basing my explicit instructions on GIMP and not on Photoshop for some simple reasons:

1) I do not own Photoshop, since I (as well as my laboratory) generally do not support commercial software and it's the 'wrong' OS;-)

2) GIMP is very powerful, stable, well documented, /free/ and available for Windows and Unix/Linux.

3) Since a fairly large number of members of this forum may well be not so rich as you seem to imply;-), I must assume that not everyone can afford buying Photoshop...This is /really/ expensive software and we don't want to steel it, right?

Take care

Bye Fridger

[chris]

Axel,

This is off-topic, but . . . I've been trying to send you mail the past couple days, but it always bounces. The error message is something to the effect of "user is out of disk space" . . .

--Chris

[Rassilon]

Both Fridger and Axel share valid points....I personally believe in sharing my knowledge so I shall...and it seems all of you missed Edwards question...He didnt ask for a DXT compliant texture...He asked for a cloud png texture...and here is a simplistic way of converting a TIFF to a PNG...

In Adobe...Load the TIFF and convert it to working RGB...Hit CTRL+A then CTRL+N then CTRL+V...Now hit 'D'...Select by Color Range at 200% Now use your Eraser tool at 100% Opaque and make the brush size 400 or rather large...Clear out all the black twice over to thin out the external layers of the clouds...Now use brightness and contrast...Lower contrast by 50-75% and heighten brightness by 50% or till you see mostly white leaving a bit of detail...It helps when you add a black layer to the back so you can see the detail But make sure you delete the additional black layer or you will be back to square one...

Now copy what you have and make an addiional layer...Blur the bottom layer with Gaussien(sp) blur at 1 px...

[OPTIONAL] - Now select foreground and background colors on your pallete as white or grey...Use Gradient tool and move your mouse to the center of the picture...Make a Gradient at 25% Opaque...This is for making gas giants usually but if you want the appearence of somewhat thick clouds...do this...Best is used with a massive grouping of clouds!

Now combine the two layers...and use the Opaque layer setting and make it between 80% and 95%....Done.

Using the above procedures produced me this cloud texture...
http://cybermindtraveller.freewebspace.com/pics/traken.jpg

On DTX I havent done those yet...so don't ask

[t00fri]

Both Fridger and Axel share valid points....I personally believe in sharing my knowledge so I shall...and it seems all of you missed Edwards question...He didnt ask for a DXT compliant texture...He asked for a cloud png texture...and here is a simplistic way of converting a TIFF to a PNG...

In Adobe...Load the TIFF and convert it to working RGB...Hit CTRL+A then CTRL+N then CTRL+V...Now hit 'D'...Select by Color Range at 200% Now use your Eraser tool at 100% Opaque and make the brush size 400 or rather large...Clear out all the black twice over to thin out the external layers of the clouds...Now use brightness and contrast...Lower contrast by 50-75% and heighten brightness by 50% or till you see mostly white leaving a bit of detail...It helps when you add a black layer to the back so you can see the detail :) But make sure you delete the additional black layer or you will be back to square one...

Now copy what you have and make an addiional layer...Blur the bottom layer with Gaussien(sp) blur at 1 px...

[OPTIONAL] - Now select foreground and background colors on your pallete as white or grey...Use Gradient tool and move your mouse to the center of the picture...Make a Gradient at 25% Opaque...This is for making gas giants usually but if you want the appearence of somewhat thick clouds...do this...Best is used with a massive grouping of clouds!

Now combine the two layers...and use the Opaque layer setting and make it between 80% and 95%....Done.

Using the above procedures produced me this cloud texture...
http://cybermindtraveller.freewebspace.com/pics/traken.jpg

On DTX I havent done those yet...so don't ask :mrgreen:

Wuff, this really sounds involved;-).

One slightly simpler remark: The conversion (GIMP) e.g. of a TIFF into a PNG format usually is just done by saving the file with .png ending rather than .tiff. Pixel gave his instructions above quite generally. So all Edwards has to do if he wanted a .png format rather than .tga, was to save the result as a .png...

Bye Fridger

[Rassilon]

I didnt see a save option under file in Gimp...I'll mess with it more..If that is so...That will cut down on alot of needless effort...but will it work with JPG files?...Besides I've been doing this with JPG files off this location...

http://xplanet.sourceforge.net/clouds_2000.jpg

Updated daily and gives me new earth like clouds to play around with

edit - On gimp...Pixel instructions above allowed me to produce a cloud pattern from TIFF...JPG is another story...With a little playing around I might be able to figure out a way to do it...

Thanks Fridger and Pixel!

[t00fri]

I didnt see a save option under file in Gimp...I'll mess with it more..If that is so...That will cut down on alot of needless effort...but will it work with JPG files?...Besides I've been doing this with JPG files off this location...

So let me share my knowledge for a change;-))

GIMP reads and converts the following formats by simply saving with the respective extension,
in 'File -> Save as'

BMP, C-Source, CEL, Fits, FLI, GBR, GIF, GIH, Glcon, HRZ, HTML, Header, JPEG, PAT, PCX, PIX, PNG, PNM, Postscript, SGI, SUNRAS, TGA, TIF(F), XBM, XCF (GIMP native). XWD, Xpm, bzip2, gzip,xjt.

You see that JPEG is included and MANY others....

Bye Fridger

[chris]

If everything works out, I'm probably going to switch a few of the textures with alpha channels to JPEG2000 format so that they can be stored much more compactly. There's a free library called Jasper for encoding and decoding JPEG2000 files that I'd like to incorporate into Celestia.

Does GIMP or Photoshop 7 support the JPEG 2000 format yet?

--Chris

[Rassilon]

I didnt see a save option under file in Gimp...I'll mess with it more..If that is so...That will cut down on alot of needless effort...but will it work with JPG files?...Besides I've been doing this with JPG files off this location...

So let me share my knowledge for a change;-))

GIMP reads and converts the following formats by simply saving with the respective extension,
in 'File -> Save as'

BMP, C-Source, CEL, Fits, FLI, GBR, GIF, GIH, Glcon, HRZ, HTML, Header, JPEG, PAT, PCX, PIX, PNG, PNM, Postscript, SGI, SUNRAS, TGA, TIF(F), XBM, XCF (GIMP native). XWD, Xpm, bzip2, gzip,xjt.

You see that JPEG is included and MANY others....

Bye Fridger

Oh but Fridger I am trying the much difficult...JPEG to PNG...and since JPEG does not have alpha info...I am gonna have to cast a spell on this one

edit - nevermind...when ever in question...just hit OK and cross your fingers...

I got the thing to work...man GIMP is sweet!

JPG2000? What is this? I am suspecting this is JPEG with alpha capabilities?

[Rassilon]

Lo and behold...

http://cybermindtraveller.freewebspace.com/pics/traken2.jpg

Damn thats sweet! I have a new toy hehe...

Now all it needs is cloud shadows...

[t00fri]

Oh but Fridger I am trying the much difficult...JPEG to PNG...and since JPEG does not have alpha info...I am gonna have to cast a spell on this one :mrgreen:

edit - nevermind...when ever in question...just hit OK and cross your fingers...

I got the thing to work...man GIMP is sweet!

JPG2000? What is this? I am suspecting this is JPEG with alpha capabilities?

You may always convert just by saving a JPEG to .PNG format. Does no harm, just means that the Alpha channel in the PNG is not used. Furthermore, you may recall a step by step instruction I wrote for you some days ago on how to merge a rgb *.JPEG file with a grayscale image carrying the level information => Alpha channel. In GIMP you compose the RGB JPG with the ALPHA by clicking Image->Compose RGBA
But beforehand the RGB jpeg has to be decomposed into its R,G,B components (also grayscale files)

Even if you kill me ;-) I am not going to repeat it once more...

Bye Fridger

[t00fri]

If everything works out, I'm probably going to switch a few of the textures with alpha channels to JPEG2000 format so that they can be stored much more compactly. There's a free library called Jasper for encoding and decoding JPEG2000 files that I'd like to incorporate into Celestia.

Does GIMP or Photoshop 7 support the JPEG 2000 format yet?

--Chris

GIMP: Not yet but in the make (Plugin). But there are also quite a number of critical voices to be heard...c.f. for example
http://www.levien.com/gimp/jpeg2000/comparison.html

Bye Fridger

[Rassilon]

Oh but Fridger I am trying the much difficult...JPEG to PNG...and since JPEG does not have alpha info...I am gonna have to cast a spell on this one

edit - nevermind...when ever in question...just hit OK and cross your fingers...

I got the thing to work...man GIMP is sweet!

JPG2000? What is this? I am suspecting this is JPEG with alpha capabilities?

You may always convert just by saving a JPEG to .PNG format. Does no harm, just means that the Alpha channel in the PNG is not used. Furthermore, you may recall a step by step instruction I wrote for you some days ago on how to merge a rgb *.JPEG file with a grayscale image carrying the level information => Alpha channel. In GIMP you compose the RGB JPG with the ALPHA by clicking Image->Compose RGBA
But beforehand the RGB jpeg has to be decomposed into its R,G,B components (also grayscale files)

Even if you kill me I am not going to repeat it once more...

Bye Fridger

No need...grasshopper learned something today ...I have done the compose RGBA and viola...the picture you see above is the results!

[t00fri]

No need...grasshopper learned something today :mrgreen:...I have done the compose RGBA and viola...the picture you see above is the results!

Don't tell me it's no fun...After this strong feeling of pride has settled in your chest;-) it's definitely time now to bumpmap the clouds and put some specular reflections into the waters.

Just tell me when you are ready;-)

Bye Fridger

[chris]

GIMP: Not yet but in the make (Plugin). But there are also quite a number of critical voices to be heard...c.f. for example
http://www.levien.com/gimp/jpeg2000/comparison.html

I'm not expecting dramatically better compression . . . I most interested in JPEG2000 because it supports an alpha channel. As far as I know, there's no other lossy compression file format that supports an alpha channel. Celestia's current Earth texture is only a PNG because it needs an alpha channel; if it was stored in a lossy format it could be much smaller. Same for the cloud textures . . .

--Chris