2024-12-09 Viewport & EEVEE Module Meeting

Practical Info

This is a weekly video chat meeting for planning and discussion of Blender Viewport & EEVEE module development. Any contributor (developer, UI/UX designer, writer, …) working on Viewport & EEVEE in Blender is welcome to join.

For users and other interested parties, we ask to read the meeting notes instead so that the meeting can remain focused.

  • Google Meet
  • Next Meeting: 20 January 2025, 11:30 AM to 12:00 PM Amsterdam Time (Your local time: 2025-01-20T10:30:00Z2025-01-20T11:00:00Z)

Attendees

  • Clement
  • James
  • Jeroen
  • Miguel

Discussion topic: Removal of geometry shader support

Geometry shaders have been used in Blender to support wide line rendering and to implement fallbacks & driver workarounds. Metal devices don’t support geometry shaders and used a workaround that only uses vertex shaders. In Blender 4.4 this has been rewritten into a common API (called primitive expansion).

During the meeting we discussed if and how we will be supporting geometry shaders in the future. Areas that can still use geometry shaders are add-ons and workarounds.

** Add-on **

We will perform some query in github to detect if geometry shaders are used. We doubt that there are add-ons/extensions actually using it. Based on this outcome we will remove geometry shaders from the Python API or add a deprecation warning that geometry shaders will be removed in the near future.

** Internal API **

We will remove geometry shaders from our internal API. Any user code in our code base will not be allowed anymore. Internally GPU backends can still use geometry shaders to work around missing GPU features for example bary-centric coordinates.

Code quality

Next meeting

The next meeting is planned on 20th of January due to the holiday seasons.

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Are any of these geometry shaders? For example POLYLINE_UNIFORM_COLOR?

The poly line shaders will use primitive expansion in 4.4. The issue are more when addons program their own geometry shaders. We don’t have sight on that.

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