Second Life Forums Archive - Bump Mapping Problem

Zante Zapedzki

We need html on a prim!

Join date: 15 Feb 2007

Posts: 123

03-31-2007 07:06

The problem involves bump mapping refusing to work on certain textures.

I'm using brightness mapping in an attempt to give life to what would otherwise be rather bland and simplistic looking textures.

In the first picture there are 3 objects. The top one has no bump mapping and the bottom 2 are set to brightness mapping. Everything is fine here.

http://marunchak.co.uk/Second_Life/Bump_1.JPG

In the second picture, the bump mapping will not register for the top object. I have tried different styles of mapping and nothing seems to work. Does this have something to do with the alpha channel used for the windows?

http://marunchak.co.uk/Second_Life/Bump_2.JPG

I'm trying to save on processing power and so I use alpha channels to simplify the geometry. Is there any way to get the object in the second picture to 'bump'?

Chosen Few

Alpha Channel Slave

Join date: 16 Jan 2004

Posts: 7,496

03-31-2007 08:23

32-bit textures cannot be bumped in SL, just as they cannot be shiny. That's all there is to it. If you want it to bump or shine, use 24-bit textures.

As for saving processing power, it's arguable whether that's what you're doing. Every 32-bit texture has to be rendered twice per frame instead of just once, and every time you can see one through another, the calculations get even more complicated. A relatively low prim build can become an FPS hog with a lot of alpha textures applied to it.

_____________________

.

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.

Zante Zapedzki

We need html on a prim!

Join date: 15 Feb 2007

Posts: 123

03-31-2007 08:37

Ah, I guess that answers it then. Alpha maps will only work with 32 bit textures as far as I'm aware. I'll go for more geometry then.

Thanks for the reply : )

Chosen Few

Alpha Channel Slave

Join date: 16 Jan 2004

Posts: 7,496

03-31-2007 10:24

From: Zante Zapedzki

Alpha maps will only work with 32 bit textures as far as I'm aware.

Just for clarification, it's not really logically sensible to say "alpha maps will only work with 32 bit textures". An alpha channel can't "work" or "not work". It either exists or it doesn't exist. What makes a 32-bit texture have 32 bits is the fact that it contains an alpha channel. If it's a 24-bit image, it means that no alpha channel is present.

The way it works is there are 8 bits per pixel in every channel. Color images have three channels (red, green, and blue), so because 8x3=24, color images are referred to 24-bit images. Color images with transparency have a total of 4 channels (red, green, blue, and alpha 1), which means they get referred to as 32-bit images since 8x4=32.

Make sense?

Anyway, the fact that 32-bit textures can't be bumped or shiny is one of SL's more annoying limitations. There's no technical reason it has to be that way. Hopefully one day they'll get around to changing that behavior.

_____________________

.

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.

Zante Zapedzki

We need html on a prim!

Join date: 15 Feb 2007

Posts: 123

03-31-2007 10:52

Thanks for the clarification Chosen. I appreciate your input and sharing of information. It makes sense to learn about these things before tackling texture creation I guess. I've only worked with it in a very linear sense using the shockwave 3D engine.

An update to the original. I'm amazed at the effect a little filtering has on a simplistic texture.

http://marunchak.co.uk/Second_Life/Bump_3.JPG

I'm having a lot of fun with Second Life atm. ; )

Welcome to the Second Life Forums Archive

Bump Mapping Problem - Please assist : )

Bump Mapping Problem - Please assist : )
Zante Zapedzki We need html on a prim! Join date: 15 Feb 2007 Posts: 123	03-31-2007 07:06 The problem involves bump mapping refusing to work on certain textures. I'm using brightness mapping in an attempt to give life to what would otherwise be rather bland and simplistic looking textures. In the first picture there are 3 objects. The top one has no bump mapping and the bottom 2 are set to brightness mapping. Everything is fine here. http://marunchak.co.uk/Second_Life/Bump_1.JPG In the second picture, the bump mapping will not register for the top object. I have tried different styles of mapping and nothing seems to work. Does this have something to do with the alpha channel used for the windows? http://marunchak.co.uk/Second_Life/Bump_2.JPG I'm trying to save on processing power and so I use alpha channels to simplify the geometry. Is there any way to get the object in the second picture to 'bump'?
Chosen Few Alpha Channel Slave Join date: 16 Jan 2004 Posts: 7,496	03-31-2007 08:23 32-bit textures cannot be bumped in SL, just as they cannot be shiny. That's all there is to it. If you want it to bump or shine, use 24-bit textures. As for saving processing power, it's arguable whether that's what you're doing. Every 32-bit texture has to be rendered twice per frame instead of just once, and every time you can see one through another, the calculations get even more complicated. A relatively low prim build can become an FPS hog with a lot of alpha textures applied to it. _____________________ . 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.
Zante Zapedzki We need html on a prim! Join date: 15 Feb 2007 Posts: 123	03-31-2007 08:37 Ah, I guess that answers it then. Alpha maps will only work with 32 bit textures as far as I'm aware. I'll go for more geometry then. Thanks for the reply : )
Chosen Few Alpha Channel Slave Join date: 16 Jan 2004 Posts: 7,496	03-31-2007 10:24 From: Zante Zapedzki Alpha maps will only work with 32 bit textures as far as I'm aware. Just for clarification, it's not really logically sensible to say "alpha maps will only work with 32 bit textures". An alpha channel can't "work" or "not work". It either exists or it doesn't exist. What makes a 32-bit texture have 32 bits is the fact that it contains an alpha channel. If it's a 24-bit image, it means that no alpha channel is present. The way it works is there are 8 bits per pixel in every channel. Color images have three channels (red, green, and blue), so because 8x3=24, color images are referred to 24-bit images. Color images with transparency have a total of 4 channels (red, green, blue, and alpha 1), which means they get referred to as 32-bit images since 8x4=32. Make sense? Anyway, the fact that 32-bit textures can't be bumped or shiny is one of SL's more annoying limitations. There's no technical reason it has to be that way. Hopefully one day they'll get around to changing that behavior. _____________________ . 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.
Zante Zapedzki We need html on a prim! Join date: 15 Feb 2007 Posts: 123	03-31-2007 10:52 Thanks for the clarification Chosen. I appreciate your input and sharing of information. It makes sense to learn about these things before tackling texture creation I guess. I've only worked with it in a very linear sense using the shockwave 3D engine. An update to the original. I'm amazed at the effect a little filtering has on a simplistic texture. http://marunchak.co.uk/Second_Life/Bump_3.JPG I'm having a lot of fun with Second Life atm. ; )