I want to share a Secret with You Guys. I know, i lose a Joker about Filesize and GameDetail by the GameContest. But i try to win 'cause i have the coolest Game, not for hiding Things. (Yes, i am a real Hero! :D) So put on Your Eyeglasses and read what i have found out.
Q: Ok, what’s going on here? Can JPG’s contain Alpha Channels or not?
A: NO! They can’t! But JPG’s can contain four COLOR Channels! The Mystic Alpha JPG’s (AJPG) are not normal RGB+A Images like TGA’s, hey are CMYK Images.
To explain:
(A): (Alpha Channel)
(RGB): (Red, Green, Blue) = 3 Color Channels
(CMYK): (Cyan, Magenta, Yellow, Black) = 4 Color Channels (Normaly used for Offset printing.)
It seems, that Blender can handle CMYK Images and sets the Colors correctly. And he use the K-Channel as Alpha Channel if You swicht to Alpha Mode in the Paint Buttons.
Q: What can i do with this Knowledge?
A: If You want to make semi Transparent Textures (Glas, Wather …), You can convert Your Image to CMYK. So You can adjust the Transparency Level by making the K-Channel brighter and darker.
Q: Can i make CutOut’s (Holes in the Texture)?
A: Yes, You can. But they don’t look so good as You would do that with TGA’s. You have to try what’s the best Solution for Your Case.
Make Youre Image in RGB Mode and add an Alpha Channel.
Convert the Pic to Multichannel. Now You got an CMY+A File, and the Colors looks a little like Stonewashed. But don’t worry, it’s OK.
Now convert the Texture to CMYK, to get a real CMYK Pic with Youre “old” Alpha as K-Channel.
Save it as JPG, it’s ready to use in Blender.
The different between TGA’s and AJPG’s is: In TGA’s, the Alpha Cannel is a separate “Layer”. In AJPG’s it’s a Component ot the Picture. You can’t switch it off by pressing the Opaque Button. You have to try what’s the best Solution for You. But in many Cases, that’s a powerful Alternative.
well…you can look at this. http://mysite.iptic.com/gargola/statusicon.blend and if you want to know how i did it,just ask me. that thing there is a simple plain with an alpha tga texture(i did the alpha texture on the gimp).i learned that from Ingie!!!
Gargola, most of us already know how to use alpha tga, but doc is the first to find you can use jpgs with cymk to achieve a similar (although not quite as good) effect. And jpgs in general are much faster than tgas.
I still don’t know where he came up with the idea to even try. Wonder if he found it in the source?
I’m not sure, that You can use more AJPG’s than TGA’s. Don’t let You deceive about the Filesize! Both have four Channels and are stored uncompressed in Memory after loading. Both have transparent Parts. So, the G-Card have to calculate Alpha-Stuff on both Images. I think there is no Advantage of AJPG’s, except the Filesize. But i dont’t know. I’ve not checked it out. If You want to make a Comparison, please post the Result.
You wondering how i get the Idea? Some Topics ago, somebody post a Link to a “mytic” Alpha-JPG. Nobody knows the Format of these File. I had a look on it with the Free Software IrfanView (this Tool can open nearly each Pic Format), and it was a CMYK Pic. I played around with this a little, and that’s the Result. Easy, isn’t it? 8)
Oh yeah, I remember that post now. Hmm, now that I think about it you’re probably right about the graphics card, although I thought I’ve read that many graphics cards will render compressed textures, but that is a proprietary compression format so…
Anyway, I’ll play around with it a bit and see what I come up with:) Thanks for the discovery.
Saluk: i know that you know how to do alpha textures or whatever LOL it’s just that so many ppl are asking a lot how to do it.(i was newbie once,you know)and i didn’t even know what a vertex was or alpha textures or anything like that…and didn’t know how to do all those stuff.what is old for you,is new for others.
could you please tell me which app u use to make ajpg without using blender? I currently use gimp(win32) for all my grafics but can’t find a cmyk function. (gimp doesn’t support cmyk until version 2 i have seen somewhere i remember correct me if im wrong)
that thing there is a simple plain with an alpha tga texture(i did the alpha texture on the gimp).i learned that from Ingie!!!