DDS Texture Alpha Problem (DXT1 compression) #18653

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Tony DiRienzo · 2009-04-29T20:34:02+02:00

Tony DiRienzo commented

2009-04-29 20:34:02 +02:00

%%%I've tested the attached file in both Blender 2.48a and Blender 2.49 RC1 (Linux i386, Python 2.5 dynamic). In 2.48a the DXT1 texture displays solid when it should have a binary alpha channel. In 2.49 RC1, the entire DXT1 texture disappears in game (which is also not the correct functionality).

Also, alpha channels are not displayed properly in the UV editor for DDS textures using the DXT1, DXT3, or DXT5 methods of compression.

You all are probably more knowledgeable on the subject than I am, but from what I understand, DXT1 uses 8-bit color channels and a 1-bit alpha channel.

I've compiled what information I have been able to find on DDS textures here:
http://blenderartists.org/forum/showthread.php?t=154090

Programming references I've found (just in case anyone should need them):

http://developer.nvidia.com/attach/6585
http://www.mindcontrol.org/~hplus/graphics/dds-info/
http://msdn.microsoft.com/en-us/library/bb943990(VS.85).aspx

The DDS files in the attached .blend were created using the GIMP DDS plugin:
http://nifelheim.dyndns.org/~cocidius/dds/
("apt-get install gimp-dds" on Ubuntu)%%%

%%%I've tested the attached file in both Blender 2.48a and Blender 2.49 RC1 (Linux i386, Python 2.5 dynamic). In 2.48a the DXT1 texture displays solid when it should have a binary alpha channel. In 2.49 RC1, the entire DXT1 texture disappears in game (which is also not the correct functionality). Also, alpha channels are not displayed properly in the UV editor for DDS textures using the DXT1, DXT3, or DXT5 methods of compression. You all are probably more knowledgeable on the subject than I am, but from what I understand, DXT1 uses 8-bit color channels and a 1-bit alpha channel. I've compiled what information I have been able to find on DDS textures here: http://blenderartists.org/forum/showthread.php?t=154090 Programming references I've found (just in case anyone should need them): http://developer.nvidia.com/attach/6585 http://www.mindcontrol.org/~hplus/graphics/dds-info/ http://msdn.microsoft.com/en-us/library/bb943990(VS.85).aspx The DDS files in the attached .blend were created using the GIMP DDS plugin: http://nifelheim.dyndns.org/~cocidius/dds/ ("apt-get install gimp-dds" on Ubuntu)%%%

Tony DiRienzo commented

2009-04-29 20:34:02 +02:00

Changed status to: 'Open'

Mitchell Stokes commented

2009-05-11 09:34:27 +02:00

%%%They appear to be correct for me. They look exactly the same in Blender as they do the BGE, and I don't see anything obviously wrong with any of them. Unless is the first one supposed to have alpha on the black part?

OS: Windows 7 Beta
GFX: NVIDIA 8600m GT
REV: 20135%%%

%%%They appear to be correct for me. They look exactly the same in Blender as they do the BGE, and I don't see anything obviously wrong with any of them. Unless is the first one supposed to have alpha on the black part? OS: Windows 7 Beta GFX: NVIDIA 8600m GT REV: 20135%%%

Tony DiRienzo commented

2009-05-11 18:51:55 +02:00

%%%Yes, the first image is supposed to have alpha on the black part.

As I stated, the alpha channels are not displayed properly in the UV editor, in Blender, or in the BGE. In order to see the image displayed properly, you will need to unpack it and view it with a DDS supporting image editor, such as The GIMP with Gimp-DDS installed (there are links for DDS plugins for popular image editors in my blenderartists thread)

I've tested with 2.49 RC2, and you are correct that the texture is once again appearing in Blender and the BGE the same (wrong) way again. In the Linux 2.49 RC1 the image was disappearing in the BGE.%%%

%%%Yes, the first image is supposed to have alpha on the black part. As I stated, the alpha channels are not displayed properly in the UV editor, in Blender, or in the BGE. In order to see the image displayed properly, you will need to unpack it and view it with a DDS supporting image editor, such as The GIMP with Gimp-DDS installed (there are links for DDS plugins for popular image editors in my blenderartists thread) I've tested with 2.49 RC2, and you are correct that the texture is once again appearing in Blender and the BGE the same (wrong) way again. In the Linux 2.49 RC1 the image was disappearing in the BGE.%%%

Dalai Felinto commented

2010-09-05 23:26:22 +02:00

%%%Is that working in Blender 2.5beta3?%%%

Amorilia commented

2010-12-21 20:49:56 +01:00

%%%For reference, I submitted a fix for this, about 9 months ago, for Blender 2.5:

http://projects.blender.org/tracker/?func=detail&aid=21590&group_id=9&atid=127%%%

%%%For reference, I submitted a fix for this, about 9 months ago, for Blender 2.5: http://projects.blender.org/tracker/?func=detail&aid=21590&group_id=9&atid=127%%%

Mitchell Stokes commented

2011-05-07 22:58:51 +02:00

%%%Armorilia's patch (except for the nvtt sync) has been committed by jesterKing in r36541. Could you verify that the problem is fixed for you?%%%

Mitchell Stokes commented

2012-05-21 07:39:50 +02:00

%%%The file looks correct in 2.63, so I'm closing this bug report. If you still have issues, please open a new bug report.%%%

Mitchell Stokes commented

2012-05-21 07:39:50 +02:00

Changed status from 'Open' to: 'Archived'

Mitchell Stokes closed this issue

2012-05-21 07:39:50 +02:00

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DDS Texture Alpha Problem (DXT1 compression) #18653