Second Life Forums Archive - What is an alpha texture?

Rebecca Hynes

I See numb3rs

Join date: 20 Feb 2007

Posts: 59

04-09-2008 13:02

If I am using a texture for a window, instead of building a frame and using the transparent texture for the glass, is that why I can see it thru other textures? In other words - if I hang a drape up there the window shows thru the drape. Is the window texture an alpha texture?

I see this all the time on other houses I own and it drives me crazy.

Keira Wells

Blender Sculptor

Join date: 16 Mar 2008

Posts: 2,371

04-09-2008 13:07

Yes.

If using alpha textures, they will overlap at some angles. It's referred to as the 'Alpha Sorting Glitch' generally, and there's really not much you can do about it, except strategically place alpha textures so that they have a non-alpha between them from normal angles.

_____________________

Tutorials for Sculpties using Blender!
Http://www.youtube.com/user/BlenderSL

Imnotgoing Sideways

Can't outlaw cute! =^-^=

Join date: 17 Nov 2007

Posts: 4,694

04-09-2008 13:09

Actually... Both textures are alpha textures and the viewer is constantly trying to decide which one should be more visible. It takes quite a bit of magic to make it work out in the end. I have the problem myself with my eyes. My evil eye is a 'contact lens' that uses an alpha texture to keep the rest of my eye visible, I like to wear glasses, and most of the hair I have has bangs made with an alpha texture. That makes 3 layers of images all fighting to be out front. (O_@)

Oh... and to answer your title question... An alpha texture is any texture that has information in the alpha (transparency) channel of the graphic file. So, even if there is no transparency at all, just having the alpha channel makes the graphic a candidate for alpha-sorting. (>_<

_____________________

Somewhere in this world; there is someone having some good clean fun doing the one thing you hate the most. (^_^)y

http://slurl.com/secondlife/Ferguson/54/237/94

Rolig Loon

Not as dumb as I look

Join date: 22 Mar 2007

Posts: 2,482

04-09-2008 16:24

To be even clearer, a texture that contains an alpha channel is a 32 bit image ... 24 bits for the RGB color channels (8 bits each) and another 8 bits for the alpha channel, which SL interprets as transparency. To read more about it, take a look at the very nicely done sticky at the top of the Texture Tips forum. Look for the link to Robin (Woods) Sojourner's excellent tutorial while you are there.

Ravenelle Zugzwang

zugzugz.com

Join date: 23 Jul 2004

Posts: 267

04-10-2008 15:42

Here is a helpful video on making transparent texture using Photoshop
http://youtube.com/watch?v=ekLIgpRHSq4

Chosen Few

Alpha Channel Slave

Join date: 16 Jan 2004

Posts: 7,496

04-10-2008 17:09

From: Ravenelle Zugzwang

Here is a helpful video on making transparent texture using Photoshop
http://youtube.com/watch?v=ekLIgpRHSq4

There's a lot of incorrect information in that video. I've been meaning to speak with Torley about it. His technique works, but certain of his explanations are way off the mark, and many of his procedural choices are questionable at best. I would not recommend that video as a learning tool.

I'm a huge Torley fan, but quite frankly, he messed up with that one.

_____________________

.

Land now available for rent in Indigo. Low rates. Quiet, low-lag mainland sim with good neighbors. IM me in-world if you're interested.

Ravenelle Zugzwang

zugzugz.com

Join date: 23 Jul 2004

Posts: 267

04-14-2008 11:05

From: Chosen Few

There's a lot of incorrect information in that video. I've been meaning to speak with Torley about it. His technique works, but certain of his explanations are way off the mark, and many of his procedural choices are questionable at best. I would not recommend that video as a learning tool.

I'm a huge Torley fan, but quite frankly, he messed up with that one.

I'll be looking forward to see your suggested corrections.

What is an alpha texture?
Rebecca Hynes I See numb3rs Join date: 20 Feb 2007 Posts: 59	04-09-2008 13:02 If I am using a texture for a window, instead of building a frame and using the transparent texture for the glass, is that why I can see it thru other textures? In other words - if I hang a drape up there the window shows thru the drape. Is the window texture an alpha texture? I see this all the time on other houses I own and it drives me crazy.
Keira Wells Blender Sculptor Join date: 16 Mar 2008 Posts: 2,371	04-09-2008 13:07 Yes. If using alpha textures, they will overlap at some angles. It's referred to as the 'Alpha Sorting Glitch' generally, and there's really not much you can do about it, except strategically place alpha textures so that they have a non-alpha between them from normal angles. _____________________ Tutorials for Sculpties using Blender! Http://www.youtube.com/user/BlenderSL
Imnotgoing Sideways Can't outlaw cute! =^-^= Join date: 17 Nov 2007 Posts: 4,694	04-09-2008 13:09 Actually... Both textures are alpha textures and the viewer is constantly trying to decide which one should be more visible. It takes quite a bit of magic to make it work out in the end. I have the problem myself with my eyes. My evil eye is a 'contact lens' that uses an alpha texture to keep the rest of my eye visible, I like to wear glasses, and most of the hair I have has bangs made with an alpha texture. That makes 3 layers of images all fighting to be out front. (O_@) Oh... and to answer your title question... An alpha texture is any texture that has information in the alpha (transparency) channel of the graphic file. So, even if there is no transparency at all, just having the alpha channel makes the graphic a candidate for alpha-sorting. (>_< _____________________ Somewhere in this world; there is someone having some good clean fun doing the one thing you hate the most. (^_^)y http://slurl.com/secondlife/Ferguson/54/237/94
Rolig Loon Not as dumb as I look Join date: 22 Mar 2007 Posts: 2,482	04-09-2008 16:24 To be even clearer, a texture that contains an alpha channel is a 32 bit image ... 24 bits for the RGB color channels (8 bits each) and another 8 bits for the alpha channel, which SL interprets as transparency. To read more about it, take a look at the very nicely done sticky at the top of the Texture Tips forum. Look for the link to Robin (Woods) Sojourner's excellent tutorial while you are there.
Ravenelle Zugzwang zugzugz.com Join date: 23 Jul 2004 Posts: 267	04-10-2008 15:42 Here is a helpful video on making transparent texture using Photoshop http://youtube.com/watch?v=ekLIgpRHSq4
Chosen Few Alpha Channel Slave Join date: 16 Jan 2004 Posts: 7,496	04-10-2008 17:09 From: Ravenelle Zugzwang Here is a helpful video on making transparent texture using Photoshop http://youtube.com/watch?v=ekLIgpRHSq4 There's a lot of incorrect information in that video. I've been meaning to speak with Torley about it. His technique works, but certain of his explanations are way off the mark, and many of his procedural choices are questionable at best. I would not recommend that video as a learning tool. I'm a huge Torley fan, but quite frankly, he messed up with that one. _____________________ . Land now available for rent in Indigo. Low rates. Quiet, low-lag mainland sim with good neighbors. IM me in-world if you're interested.
Ravenelle Zugzwang zugzugz.com Join date: 23 Jul 2004 Posts: 267	04-14-2008 11:05 From: Chosen Few There's a lot of incorrect information in that video. I've been meaning to speak with Torley about it. His technique works, but certain of his explanations are way off the mark, and many of his procedural choices are questionable at best. I would not recommend that video as a learning tool. I'm a huge Torley fan, but quite frankly, he messed up with that one. I'll be looking forward to see your suggested corrections.

Welcome to the Second Life Forums Archive

What is an alpha texture?