Metal: Partial texture update failing when using float images. #103658

New Issue

Jeroen Bakker · 2023-01-05T13:03:50+01:00

Jeroen Bakker commented

2023-01-05 13:03:50 +01:00

System Information
Operating system: macOS-12.6-arm64-arm-64bit 64 Bits
Graphics card: Metal API Apple M1 Ultra 1.2

Blender Version
Broken: version: 3.5.0 Alpha, branch: master, commit date: 2023-01-05 11:40, hash: 4813c37ae2
Worked: (newest version of Blender that worked as expected)

Short description of error
With the metal backend enabled, 3d texturepainting on float images only show the last updated partial image.
Issue doesn't appear on byte textures.

Exact steps for others to reproduce the error

In user pref enable Metal as GPU Backend.
Go to texture paint mode.
Select single texture, create a float texture with a resolution higher then 256x256.
Start painting.

See file where the mentioned steps are already done. Just paint inside the 3d viewport.
metal-texturepainting.blend

Screen Recording 2023-01-05 at 13.02.06.mov

**System Information** Operating system: macOS-12.6-arm64-arm-64bit 64 Bits Graphics card: Metal API Apple M1 Ultra 1.2 **Blender Version** Broken: version: 3.5.0 Alpha, branch: master, commit date: 2023-01-05 11:40, hash: `4813c37ae2` Worked: (newest version of Blender that worked as expected) **Short description of error** With the metal backend enabled, 3d texturepainting on float images only show the last updated partial image. Issue doesn't appear on byte textures. **Exact steps for others to reproduce the error** * In user pref enable Metal as GPU Backend. * Go to texture paint mode. * Select single texture, create a float texture with a resolution higher then 256x256. * Start painting. See file where the mentioned steps are already done. Just paint inside the 3d viewport. [metal-texturepainting.blend](https://archive.blender.org/developer/F14115210/metal-texturepainting.blend) [Screen Recording 2023-01-05 at 13.02.06.mov](https://archive.blender.org/developer/F14115212/Screen_Recording_2023-01-05_at_13.02.06.mov)

Jeroen Bakker commented

2023-01-05 13:03:50 +01:00

Added subscriber: @Jeroen-Bakker

Michael Parkin-White was assigned by Jeroen Bakker

2023-01-05 13:04:57 +01:00

Michael Parkin-White commented

2023-01-05 16:02:13 +01:00

Looks like there were two separate issues occurring here:

Sometimes, Texture::update_sub is called with an extent dimension of zero, causing a validation failure in Metal. Adding an early exit for these cases fixes this.
When a staging texture is used for the texture update (required when format is not directly writeable and format conversion is needed), the final staging texture blit overrides all existing contents of the texture, rather than just the region which is updated.

I'm trying to determine whether it is more optimal to initialise the staging texture with the existing textures contents via a blit operation, and then blit the entire staging texture back (less CPU API overhead), or, only update the region modified (Increased API overhead for texture arrays and cube maps as each slice requires separate blit call, but very slightly reduced GPU overhead for the simple case.)

Will submit an initial patch anyhow. Both solutions are immeasurably different, so this can always be looked at again in future. Texture updating in general is not particularly nice, due to all of the complexity of how the texture can be updated.

Patch coming shortly.

Looks like there were two separate issues occurring here: 1) Sometimes, Texture::update_sub is called with an extent dimension of zero, causing a validation failure in Metal. Adding an early exit for these cases fixes this. 2) When a staging texture is used for the texture update (required when format is not directly writeable and format conversion is needed), the final staging texture blit overrides all existing contents of the texture, rather than just the region which is updated. I'm trying to determine whether it is more optimal to initialise the staging texture with the existing textures contents via a blit operation, and then blit the entire staging texture back (less CPU API overhead), or, only update the region modified (Increased API overhead for texture arrays and cube maps as each slice requires separate blit call, but very slightly reduced GPU overhead for the simple case.) Will submit an initial patch anyhow. Both solutions are immeasurably different, so this can always be looked at again in future. Texture updating in general is not particularly nice, due to all of the complexity of how the texture can be updated. Patch coming shortly.

blender-admin commented

2023-01-08 16:16:21 +01:00

This issue was referenced by d3f626b535

This issue was referenced by d3f626b535313af616b0574958b2d064fc88c5d3

Germano Cavalcante commented

2023-01-09 21:50:47 +01:00

Changed status from 'Needs Triage' to: 'Confirmed'

Germano Cavalcante commented

2023-01-09 21:50:47 +01:00

Added subscriber: @mano-wii

Philipp Oeser removed the

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Metal: Partial texture update failing when using float images. #103658