If Alpha is 0, then do not have a way to access the origin rgb values.

Anyone knows what can I do to use VEX get rgba without pre multiply alpha. Thanks a lot.

I've not seen this before. Each channel is read independently. I use textures with zero data in the alpha without issues.

I found this with PNG. Support told me to set an envvar to tell it to not automatically premult:


The other way is to load the image through cops, set the premult/unpremult on the file cop, and reference the image into your vex wrangle via the op: syntax.

mestela
I found this with PNG. Support told me to set an envvar to tell it to not automatically premult:

export OPENIMAGEIO_IMAGECACHE_OPTIONS=unassociatedalpha=1.max_memory_MB=8192

The other way is to load the image through cops, set the premult/unpremult on the file cop, and reference the image into your vex wrangle via the op: syntax.

Hellow, Where is this added to？
I added Variables, it didn't work.