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Dylan Rickenbacker
Animator
Join date: 11 Oct 2006
Posts: 365
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11-26-2008 00:39
I've noticed that many textures have alpha channels although they don't really need them, thus unnecessarily maximizing sorting issues. It happens very often with marble textures, for example.
I tend to remove the alpha channel in those cases with the quick and dirty method - I save the texture to my hard drive, convert it to JPG and upload it again.
My question: Is there any downside to that? I'm asking because I'm not really texture-savvy, I just notice that many texture artists seem to consider PNG and TGA the pure doctrine, so I'm wondering if I'm losing anything important by using JPG.
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Viktoria Dovgal
…
Join date: 29 Jul 2007
Posts: 3,593
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11-26-2008 01:06
The only trouble with saving to JPEG is that you're adding some lossy compression. The original texture file gets compressed to JPEG 2000 when it's uploaded to SL, and then you are adding another compression step when you save to JPEG, and then it gets recompressed a third time when it's converted at upload time. If you save locally to either TGA or PNG with alpha switched off, you can eliminate one of those lossy conversions.
On the other hand, if the textures look well enough with the method you're using, carry on =)
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Larrie Lane
Registered User
Join date: 9 Feb 2007
Posts: 667
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11-26-2008 02:42
From: Viktoria DovgalIf you save locally to either TGA or PNG with alpha switched off, you can eliminate one of those lossy conversions.[/QUOTE
How do you switch Alpha off?
I thought the standard method was to save as 24bit for textures containing no Alpha Channels and 32bit for textures with Alpha Channels.
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Viktoria Dovgal
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Join date: 29 Jul 2007
Posts: 3,593
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11-26-2008 03:08
From: Larrie Lane How do you switch Alpha off? Depends on what program you're using to save the image. Good stuff will let you choose whether or not to include an alpha channel. From: someone I thought the standard method was to save as 24bit for textures containing no Alpha Channels and 32bit for textures with Alpha Channels. Well 8 bits per channel yes, but most programs are kind and offer a checkbox to include alpha or not. |
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Isablan Neva
Mystic
Join date: 27 Nov 2004
Posts: 2,907
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11-26-2008 08:11
There are a whole bunch of freebie marble textures out there that were saved as 32 bit alphas - those suckers have been tormenting builders in SL for at least 4 years.
The answer, as you've discovered, is to download them and re-save as a 24 bit. Otherwise, they will indeed make you miserable when trying to use them.
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 http://slurl.com/secondlife/TheBotanicalGardens/207/30/420/
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Sindy Tsure
Will script for shoes
Join date: 18 Sep 2006
Posts: 4,103
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11-26-2008 08:32
Are there copyright issues here?
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Atom Burma
Registered User
Join date: 30 May 2006
Posts: 685
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11-29-2008 03:59
There are copyright issues yes. Some people and shops specify that they don't like, or don't care about 3rd party manipulation. Legally I suppose using a texture you bought in SL, and capturing it is questionable. Using that capture in SL technically would still be in their TOS. Because you are not using it out of world, or selling it.
I have had both scenerios. The irony is that they are probably stolen themselves. Most freebee textures are from renderosity.com and the like, from their freebee sections.
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