Maniphest T104016

Metal backend has distorted image outline in video sequencer.
Needs Information from Developers, Normal
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Assigned To
Michael Parkin-White (MichaelPW)
Authored By
Alaska (Alaska)
Fri, Jan 20, 5:57 AM
Tags
  • BF Blender
  • Platform: macOS
  • EEVEE & Viewport
Subscribers
Alaska (Alaska)
Germano Cavalcante (mano-wii)
Michael Parkin-White (MichaelPW)
Pratik Borhade (PratikPB2123)
Richard Antalik (ISS)

Description

System Information
Operating system: macOS-13.1-arm64-arm-64bit 64 Bits
Graphics card: Metal API Apple M1 Pro 1.2

Blender Version
Broken: version: 3.5.0 Alpha, branch: master, commit date: 2023-01-20 04:20, hash: rB1e8cc72f85f0
Worked: NA

Short description of error
When the Metal GPU backend is used for the Blender UI, then the outline on the image in the video sequencer previewer appears distorted. This issue does not occur if the OpenGL backend is used.

OpenGLMetal

The issue is with the Metal image showing a white line running from the centre of the image to the upper right. This is part of the "Image outline" provided by the Blender UI.

Exact steps for others to reproduce the error

  1. Open Blender on a Mac.
  2. Open the preferences window.
  3. In the System tab change the backend to Metal, save the preferences, then close and re-open Blender.
  4. In the newly opened Blender, select from the top left File -> New -> Video Editing
  5. Add a image or video to the time line.
  6. In the preview window found above the time line, you will see the image with the distorted outline. If you do not see the image or distorted outline, make sure you adjust the position on the time line so the current frame is over the image/video, and that you have the image or video selected in the time line.

Related Objects

Event Timeline

Alaska (Alaska) created this task.Fri, Jan 20, 5:57 AM
Pratik Borhade (PratikPB2123) added a project: Platform: macOS.Fri, Jan 20, 11:52 AM
Pratik Borhade (PratikPB2123) added a subscriber: Pratik Borhade (PratikPB2123).
Richard Antalik (ISS) added a subscriber: Richard Antalik (ISS).Fri, Jan 20, 8:19 PM

Can't reproduce on
Operating system: macOS-13.0.1-x86_64-i386-64bit 64 Bits
Graphics card: AMD Radeon Pro 5700 XT OpenGL Engine ATI Technologies Inc. 4.1 ATI-4.9.48

Germano Cavalcante (mano-wii) changed the task status from Needs Triage to Needs Information from Developers.Fri, Jan 20, 11:00 PM
Germano Cavalcante (mano-wii) added a project: EEVEE & Viewport.
Germano Cavalcante (mano-wii) added a subscriber: Germano Cavalcante (mano-wii).

I can confirm.

This is a case where GPU_PRIM_LINE_LOOP is used but not supported for Metal.

There are other similar cases (proportional edit circle, snap circle...)

Not sure how this will be handled (T96261: Metal Viewport )

Michael Parkin-White (MichaelPW) added a subscriber: Michael Parkin-White (MichaelPW).Mon, Feb 6, 2:24 PM
Michael Parkin-White (MichaelPW) added a comment.Mon, Feb 6, 2:28 PM

Thanks for highlighting, should be a fairly straight forward fix. There are cases where Line Loop should be emulated, but generally more optimal and consistent to fix the calling code, as it only involves ejecting one extra vertex.
Will submit a patch soon.

Michael Parkin-White (MichaelPW) claimed this task.Mon, Feb 6, 2:28 PM