Tx Manger - remove unused textures

[TzurH]

I think it would be great to have a 'remove unused' textures button. The Tx Manager UI can get quite cluttered without this.

Similar functionality to the "Reset" button, but without clearing the user's manual rules.

[prman-pixar]

@TzurH can you give me some steps to follow to get it into a state where there are unused textures in the manager? Right now, I can't get it into that state.

[TzurH]

Hmm, I'm not sure how it happened to be honest. If I come across it again, I'll report here.

[prman-pixar]

@TzurH I added a button to do this. Let me know if it works or not.

[TzurH]

I get the following error when I try it.

Python: Traceback (most recent call last):
  File "C:\Users\zurho\AppData\Roaming\Blender Foundation\Blender\2.93\scripts\addons\RenderManForBlender-main\rman_ui\rman_ui_txmanager.py", line 249, in execute
    if getattr(node, param) != item.name:
AttributeError: 'NoneType' object has no attribute 'filename'

location: <unknown location>:-1

I have loaded .tex textures just so they're loaded into texture manager, then I've replaced those with the .exr files.

[prman-pixar]

@TzurH Can you see if the latest commit fixes the problem?

[TzurH]

@prman-pixar I no longer get an error, but the unused textured aren't getting cleared from the tx manager.

maybe I'm not using it properly?

started a new scene
added a cube
add pxrSurface material to the cube
load in a few textures using PxrTexture nodes
delete a few textures from the material - they are still loaded in tx manager
hit the clear unused button - nothing happens. unused textures are still in tx manager

[prman-pixar]

@TzurH OK, good to know. I think this is also related to GitHub #638. The IDs just aren't unique enough, so I'll have to come up with a workaround.