Some test images use incorrect KTXorientation key name

[sevmeyer]

I have noticed that some test images use the incorrect metadata key KTXOrientation (uppercase O), instead of the correct KTXorientation:

• cubemap_yokohama_astc_8x8_unorm.ktx
• cubemap_yokohama_bc3_unorm.ktx
• cubemap_yokohama_etc2_unorm.ktx
• metalplate-amg-rgba8.ktx
• not4_rgb888_srgb.ktx
• pattern_02_bc2.ktx
• texturearray_astc_8x8_unorm.ktx
• texturearray_bc3_unorm.ktx
• texturearray_etc2_unorm.ktx

I don't expect anything to catch on fire because of this, but it seems worthwhile to mention it.

[MarkCallow]

I noticed these when working on ktx2ktx2. It caused me to add a feature to drop such invalid metadata or optionally rewrite it during the conversion. I don't have a good way to fix these .ktx files as I don't have the original images. (I would really like to get those for the Yokohama cubemap). I will have to resort to a binary editor I suppose.

Are you up for creating a PR with the fixes?

[sevmeyer]

No problem. I found the incorrect keys while working on a simple KTX inspection tool, which also can be used to fix the files. The real challenge was to review the changes in Git.

On this subject, I'm working on a repository with custom KTX test files, including files with errors. Hopefully, that will be a useful contribution to the pool of test data for KTX tools.

[MarkCallow]

IIRC, I created metalplate* and not4* using PVRTexTool. Maybe it is the guilty party in the other images too, which I found on the net. I just checked and found "KTXOrientation" in the binary. It is indeed the culprit.

[MarkCallow]

I reported this to Imagination:

https://forums.imgtec.com/t/pvrtextool-setting-incorrect-ktx-metadata/3024

[jherico]

@MarkCallow The original yokohama images are these I believe:
http://www.humus.name/Textures/Yokohama3.zip

They're JPG, but they appear to be higher quality than the KTX existing compressed versions (i.e. no terrible banding in the sky)

[jherico]

Here's the ktx version: https://s3.amazonaws.com/Oculus/cubemap_yokohama_rgba32.zip

[jherico]

oops... looks like I accidentally found the culprit for the original bug.... my cubemap was created using PVRTexTool, and it appears to have put the incorrect KTXOrientation name in. I've posted in their forum about the issue here: https://forums.imgtec.com/t/incorrect-invalid-ktx-key-value-data/3047

[MarkCallow]

Thanks for the pointer to the Yokohama cubemaps. If I have time next week I'll try to create a Basis compressed .ktx2. I'd like to make new .ktx files of the ETC2, ASTC & BC3 versions as well.

As I noted in an earlier comment, I posted in the imgtec forum as well. There has been no response.

[jherico]

Whoops... should have read the whole thread I guess.

[MarkCallow]

No worry. The extra post in the forum will show multiple people are interested in a fix.