[BUG] oiiotool tile issue with otex and prman

[MrLixm]

Describe the bug

I have a strange behvior when using oiiotool with the -otex option.

I am trying to export "tex" textures for renderman using oiiotool (and intentionnaly not maketx).
What I found is that I need to manually set the --tile to 32 32 for the texture to be read properly by prman.
However I found that the tile option only works if I force the bitdepth with -d.

OpenImageIO version and dependencies

I tested on 2 oiio version:

• hoiiotool shipped Houdini 20.5.332 on Windows

OIIO 2.3.14 built for C++17/201703 sse2

• oiiotool compiled on linux

OIIO 2.5.7.0 built for C++14/201402 sse2,sse3,ssse3,sse41,sse42

To Reproduce

oiiotool texture.exr --planarconfig separate --tile 32 32 -otex:prman_metadata=1:prman_options=1:resize=1 texture.exr

doesn't work the tile size is still 64x64 (inspected with oiiotool -v --info)

oiiotool texture.exr --planarconfig separate --tile 32 32 -d half -otex:prman_metadata=1:prman_options=1:resize=1 texture.exr

now work, the tile size is 32x32

(the same behavior is observed with the -otex:tile=32x32:type=half syntax)

Hints

What I also found is that removing the prman options also seems to fix it, i.e.

oiiotool texture.exr --planarconfig separate --tile 32 32 -otex texture.exr

will work

[jessey-git]

OpenImageIO calculates the prman tile size based on the data format that is used. See here:
https://github.com/AcademySoftwareFoundation/OpenImageIO/blob/main/src/libOpenImageIO/maketexture.cpp#L72

That code would explain why you only get 32x32 when using half etc.

The values used have been untouched for 12 years. I can't quite find any definitive documentation about what tile sizes are acceptable though. Maybe they are out of date?

[pleprince]

This is not a bug. Prman's texture cache uses fixed-size slots. This is a feature.