Texture compression algorithm mysteriously producing black squares if DXT5

allenweisse

Newbie

Posts: 26

Texture compression algorithm mysteriously producing black squares if DXT5

« on: May 01, 2024, 19:08 »

I saw the issue raised by Dreadfred and answered by Gildor here:

Quote from: Gildor on November 20, 2021, 23:48

Hi. Probably these blocks are transparent (has something encoded into texture's alpha channel), so your image viewer just ignores any color of pixels when displaying it.

Though it seems these 3x3 blocks aren't "culling" what's beneath the alpha channel (if I understood that correctly)
Sometimes exporting uncompressed TARGA fails, so my solution then is selecting 3x3 black squares in GIMP and resynthesizing

Just thought I'd raise this slight issue

affected_texture.png (446.85 KB, 934x534 - viewed 647 times.)
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spiritovod

Global Moderator
Hero Member

Posts: 2733

Re: Texture compression algorithm mysteriously producing black squares if DXT5

« Reply #1 on: May 02, 2024, 17:31 »

@allenweisse: Converting compressed DXT textures to other formats is lossy anyway due to thresholds in the algorithm (even to uncompressed TGA). It's recommended to export textures as-is (to dds) when possible and convert them outside umodel to prevent possible issues or quality loss, because results may vary depending on particular implementation (like slightly brighter/darker image, different handling of alpha channel, etc).


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spiritovod

Global Moderator
Hero Member

Posts: 2733

Re: Texture compression algorithm mysteriously producing black squares if DXT5

« Reply #2 on: June 25, 2025, 00:25 »

Quote from: allenweisse on May 01, 2024, 19:08

Just thought I'd raise this slight issue

Bumping with the quote to ping OP. This should be fixed in three general specific builds, as DXT5 is processed differently now.


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allenweisse

Newbie

Posts: 26

Re: Texture compression algorithm mysteriously producing black squares if DXT5

« Reply #3 on: July 20, 2025, 06:53 »

Lovely, because I've always had this as an extra step when doing bulk exports- to extract PF_DXT5 instances as .dds and convert to .png


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