DCM Notes for 2024-05-06

[PathogenDavid]

Bonsai.Shaders issues

We mainly talked about this collection of semi-related Bonsai.Shaders-related issues I recently submitted:

• Consider binding textures to their uniform slots rather than texture units #1776
• Unrelated texture operations mess up texture bindings #1773
• StoreImage can dispose of textures that are still on use on the GPU #1774
• StoreImageSequence leaks GPU memory #1775

These issues are related in the sense that they can (and perhaps should) be solved all at once since their solutions rely on common infrastructure.

Everyone seemed in favor of binding to uniform slots rather than texture units. This is actually already how it works for textures bound to a material directly in the Shader Resources node (if you add a TextureBindingConfiguration to the buffer bindings.) We should also update that to remove the texture unit selection since it's not important to expose to the user and we will begin dynamically allocating them.

It was pointed out that during this change we might be able to make the uniform name selection a dropdown (or perhaps a combo box) to aid in uniform name selection.

For the premature disposal / leak issues: There was concern that the unpredictable behavior of finalization could be undesirable if leaked resources get disposed of randomly or GPU resources aren't freed eagerly enough, so reference counting will be ideal.

It was noted that we need to ensure cases like providing textures via ResourceSubject are properly handled.

XML Namespace Prefixes of script extensions

• Automatic XmlNamespacePrefix for extension projects #1777

Right now extensions without an XmlNamespacePrefix get an automatically-assigned prefix (IE: p1 etc.)

@bruno-f-cruz mentioned it's possible to get in a case where these prefixes get out of sync between a parent workflow and its included workflow, breaking the file. He's just been fixing them manually, but ideally we should try to fix this. He will get us a more detailed repro later.

We also discussed that it's odd that script extensions don't get a default prefix.

It was also discovered that the prefix attribute does not work correctly when there's no namespace (as is typical for script extensions given the default template.)

Scene file support (glTF/USD + PBR)

• Name a first-class scene format (glTF or USD) and adopt physically based rendering #1779

What started as a discussion about updating Assimp.NET to possibly fix broken support for newer Blender .blend files evolved into a discussion about possibly nominating a single modern file format (glTF or USD) as the first-class 3D scene format supported by Bonsai.

This was towards the end of the meeting so we had to wrap things up, but I rambled out my thoughts in the linked issue. Somewhat related as the talk of providing in-box support for physically based rendering, which would naturally fall out of glTF support.