"Use Alpha" in Texture settings do not influence to Normal #43821

New Issue

3dvits@gmail.com · 2015-02-26T12:35:49+01:00

3dvits@gmail.com commented

2015-02-26 12:35:49 +01:00

System Information
All

Blender Version
Broken: up to 2.73a

Short description of error
Check box "Use Alpha" and "Use" on Image Sampling -> Alpha section of Texture panel do not influence to Normal

Exact steps for others to reproduce the error
http://youtu.be/_M3o1kVQaso

open attached file
go to Texture panel
select texture "Test"
check on and off check box "Use Alpha" on Image section and/or "Use" on Image Sampling -> Alpha section.
bugUseAlpha-Normal.blend

**System Information** All **Blender Version** Broken: up to 2.73a **Short description of error** Check box "Use Alpha" and "Use" on Image Sampling -> Alpha section of Texture panel do not influence to Normal **Exact steps for others to reproduce the error** http://youtu.be/_M3o1kVQaso 1) open attached file 2) go to Texture panel 3) select texture "Test" 4) check on and off check box "Use Alpha" on Image section and/or "Use" on Image Sampling -> Alpha section. [bugUseAlpha-Normal.blend](https://archive.blender.org/developer/F145953/bugUseAlpha-Normal.blend)

3dvits@gmail.com commented

2015-02-26 12:35:49 +01:00

Changed status to: 'Open'

3dvits@gmail.com commented

2015-02-26 12:35:49 +01:00

Added subscriber: @VitaliiShmorgun

Julian Eisel commented

2015-02-26 19:09:52 +01:00

Added subscriber: @JulianEisel

Julian Eisel commented

2015-02-26 19:09:52 +01:00

The images aren't included in your .blend, so could you use the "Pack All Into .blend" function (just use the search menu) and upload again?

3dvits@gmail.com commented

2015-02-26 23:22:03 +01:00

Sorry. I forgot.
bugUseAlpha-Normal.blend

Sorry. I forgot. [bugUseAlpha-Normal.blend](https://archive.blender.org/developer/F146036/bugUseAlpha-Normal.blend)

perfection cat commented

2015-03-03 04:09:48 +01:00

Added subscriber: @sindra1961

perfection cat commented

2015-03-03 04:09:48 +01:00

I made the png file which I added an alpha channel to from the jpeg file in the blend file which you attached.
I made it in image-editor of Blender.
It was different from the result that you reported.
The version that I used.

version 2.73 (sub 0), branch b'master', commit date b'2015-01-20' b'18:16', hash b'bbf09d9', b'Release'
version 2.73 (sub 9), branch b'master', commit date b'2015-03-02' b'00:05', hash b'56935e2', b'Release'

Result.blend

I may misunderstand the contents which you report.

I made the png file which I added an alpha channel to from the jpeg file in the blend file which you attached. I made it in image-editor of Blender. It was different from the result that you reported. The version that I used. version 2.73 (sub 0), branch b'master', commit date b'2015-01-20' b'18:16', hash b'bbf09d9', b'Release' version 2.73 (sub 9), branch b'master', commit date b'2015-03-02' b'00:05', hash b'56935e2', b'Release' [Result.blend](https://archive.blender.org/developer/F146855/Result.blend) ![Result.blend.png](https://archive.blender.org/developer/F146856/Result.blend.png) I may misunderstand the contents which you report.

3dvits@gmail.com commented

2015-03-03 09:39:50 +01:00

My image actually png, as you can see in this screen capture
Your image work well, because you use RGBA with 16 bits float. It mean that this bug reproduced only with RGBA 8-bit per channel.
This help me in my work, but bug is still actual.

My image actually png, as you can see in this screen capture ![bb.png](https://archive.blender.org/developer/F146903/bb.png) Your image work well, because you use RGBA with 16 bits float. It mean that this bug reproduced only with RGBA 8-bit per channel. This help me in my work, but bug is still actual.

perfection cat commented

2015-03-04 01:38:04 +01:00

A result seems to vary according to a form of color depth of the png file so that you say.
Color_Depth_Diff.blend

A result seems to vary according to a form of color depth of the png file so that you say. [Color_Depth_Diff.blend](https://archive.blender.org/developer/F147136/Color_Depth_Diff.blend)

Antonis Ryakiotakis was assigned by Julian Eisel

2015-03-09 00:08:44 +01:00

Julian Eisel commented

2015-03-09 00:08:44 +01:00

Added subscriber: @Psy-Fi

Julian Eisel commented

2015-03-09 00:08:44 +01:00

Not sure how that should work... maybe @Psy-Fi does?

perfection cat commented

2015-03-09 04:52:36 +01:00

Those color channels are different when color depth is 8 or 16.

Those color channels are different when color depth is 8 or 16. ![screen.png](https://archive.blender.org/developer/F148297/screen.png)

Antonis Ryakiotakis commented

2015-03-09 19:10:20 +01:00

I'm not sure I understand what user would expect here.. The normal of the last image covering up the previous normal based on alpha or so?

3dvits@gmail.com commented

2015-03-10 00:17:42 +01:00

The normal of the last image covering up the previous normal based on alpha or so?

Yes. Like with all other texture influence types. And like with 16 bits per channel normal map. It will be useful, if you want to combine couple normal map on one object and, may be, bake this result to new texture.
For me it can be workaround of this bug https://developer.blender.org/T43274

>The normal of the last image covering up the previous normal based on alpha or so? Yes. Like with all other texture influence types. And like with 16 bits per channel normal map. It will be useful, if you want to combine couple normal map on one object and, may be, bake this result to new texture. For me it can be workaround of this bug https://developer.blender.org/T43274

Antonis Ryakiotakis commented

2015-03-10 12:02:05 +01:00

Changed status from 'Open' to: 'Archived'

Antonis Ryakiotakis closed this issue

2015-03-10 12:02:05 +01:00

Antonis Ryakiotakis commented

2015-03-10 12:02:05 +01:00

Bump maps are not really made to handle alpha, they are data, not color. And this is sort of understandable. Heights are not "transparent", this only makes sense for color. Initially the design was to use one channel per image if you check at the code (and postponed until we had proper support for those).

The pngs is a different issue but that works as expected too: Bump maps are loaded to OpenGL as data so they don't pass through our color management pipeline. 16 bit images are loaded as premultiplied in blender so they are multiplied by their alpha. During color management pipeline they are converted to straight space before being uploaded to OpenGL, unless they are treated as data. So for data textures, 8 bit pngs are already in straight space, and get the full opaque color, while 16bit pngs stay as premultiplied have the alpha taken into account.

What does work is a stencil texture, but that will also influence color textures. So I guess verdict here is that you can't really mix bump maps with a factor in the texture stack.

Bump maps are not really made to handle alpha, they are data, not color. And this is sort of understandable. Heights are not "transparent", this only makes sense for color. Initially the design was to use one channel per image if you check at the code (and postponed until we had proper support for those). The pngs is a different issue but that works as expected too: Bump maps are loaded to OpenGL as data so they don't pass through our color management pipeline. 16 bit images are loaded as premultiplied in blender so they are multiplied by their alpha. During color management pipeline they are converted to straight space before being uploaded to OpenGL, unless they are treated as data. So for data textures, 8 bit pngs are already in straight space, and get the full opaque color, while 16bit pngs stay as premultiplied have the alpha taken into account. What does work is a stencil texture, but that will also influence color textures. So I guess verdict here is that you can't really mix bump maps with a factor in the texture stack.

3dvits@gmail.com commented

2015-03-10 13:24:19 +01:00

If you can do this in blender:
http://youtu.be/_UBrifFT-4w
using mask and node editor, then it is not a technical problem at all. Normal map data collect in 3 channels as a 3 component vector. Then if you have alpha channel in image, you can use this data for making similar effect.
Or you can fix this bug https://developer.blender.org/T43274 and I will be happy.
NormalMasking.blend

If you can do this in blender: http://youtu.be/_UBrifFT-4w using mask and node editor, then it is not a technical problem at all. Normal map data collect in 3 channels as a 3 component vector. Then if you have alpha channel in image, you can use this data for making similar effect. Or you can fix this bug https://developer.blender.org/T43274 and I will be happy. [NormalMasking.blend](https://archive.blender.org/developer/F149500/NormalMasking.blend)

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"Use Alpha" in Texture settings do not influence to Normal #43821