First render of barbershop appears different #92416

New Issue

William Leeson · 2021-10-22T18:43:00+02:00

William Leeson commented

2021-10-22 18:43:00 +02:00

Load the barbershop scene
hit F12 to render
save the image
hit F12 to render again
save the image
now compare the 2 they are different

1. Load the barbershop scene 2. hit F12 to render 3. save the image 4. hit F12 to render again 5. save the image 6. now compare the 2 they are different |![CPU_barbarshop.png](https://archive.blender.org/developer/F11391501/CPU_barbarshop.png)|![CPU_barbarshop.png](https://archive.blender.org/developer/F11391544/CPU_barbarshop.png)| | -- | -- |

William Leeson commented

2021-10-22 18:43:00 +02:00

Added subscriber: @leesonw

Alaska commented

2021-10-23 02:04:00 +02:00

Added subscriber: @Alaska

Alaska commented

2021-10-23 02:04:00 +02:00

I can reproduce this issue in Blender versions:
2.80
2.81
2.82
2.83
2.90
2.91
2.92
2.93
3.0

2.79 is the first version of Blender that doesn't show this issue.

However, rendering the scene once, then saving it, resolves the issue for every future time you open the file.

I can reproduce this issue in Blender versions: 2.80 2.81 2.82 2.83 2.90 2.91 2.92 2.93 3.0 2.79 is the first version of Blender that doesn't show this issue. However, rendering the scene once, then saving it, resolves the issue for every future time you open the file.

Richard Antalik commented

2021-10-27 10:14:20 +02:00

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

Raimund Klink commented

2021-10-28 00:04:40 +02:00

Added subscriber: @Raimund58

Raimund Klink commented

2021-10-28 00:04:40 +02:00

Funny thing, I always thought it was a known issue and never reported it.

Lukas Stockner commented

2022-10-19 01:33:51 +02:00

Added subscribers: @brecht, @LukasStockner

Lukas Stockner self-assigned this 2022-10-19 01:33:51 +02:00

Lukas Stockner commented

2022-10-19 01:33:51 +02:00

The problem here is related to some textures' colorspace setting.

In particular, some textures are set to sRGB EOTF, which the default Blender color config doesn't recognize. Therefore, IMB_colormanagement_check_file_config clears the colorspace property, assuming that it will be filled back in when the ImBuf is acquired the first time.

However, Cycles queries the image's colorspace in intern/cycles/blender/shader.cpp before the image is ever loaded, so it gets the empty value back. Later, the image is loaded (when BlenderImageLoader::load_metadata queries its size), so for the second render the colorspace is now initialized and everything works.

A simple fix is to call b_image.size() in add_node (in shader.cpp) before getting the colorspace so that it's initialized. I don't think this comes with performance concerns, since we would trigger an image load later anyways. @brecht, do you have a better idea?

The problem here is related to some textures' colorspace setting. In particular, some textures are set to `sRGB EOTF`, which the default Blender color config doesn't recognize. Therefore, `IMB_colormanagement_check_file_config` clears the colorspace property, assuming that it will be filled back in when the `ImBuf` is acquired the first time. However, Cycles queries the image's colorspace in `intern/cycles/blender/shader.cpp` before the image is ever loaded, so it gets the empty value back. Later, the image is loaded (when `BlenderImageLoader::load_metadata` queries its size), so for the second render the colorspace is now initialized and everything works. A simple fix is to call `b_image.size()` in `add_node` (in `shader.cpp`) before getting the colorspace so that it's initialized. I don't think this comes with performance concerns, since we would trigger an image load later anyways. @brecht, do you have a better idea?

Brecht Van Lommel commented

2022-10-19 19:44:48 +02:00

We don't want to load images early, it should be done later and multi-threaded. We may also end up optimizing out the shader node using the image and not need to load it at all.

Could we set metadata.colorspace in BlenderImageLoader::load_metadata, for cases where the colorspace was not known earlier?

We don't want to load images early, it should be done later and multi-threaded. We may also end up optimizing out the shader node using the image and not need to load it at all. Could we set `metadata.colorspace` in `BlenderImageLoader::load_metadata`, for cases where the colorspace was not known earlier?

blender-admin commented

2022-11-08 22:05:20 +01:00

This issue was referenced by 1c27cc5529

This issue was referenced by 1c27cc55294a88a9472c8a4f7727fce4ebce6f30

blender-admin commented

2022-11-08 22:05:20 +01:00

This issue was referenced by 15b2b53b87

This issue was referenced by 15b2b53b87ab088e4869dfb0af991c9eb2be2d68

blender-admin commented

2022-11-08 22:05:20 +01:00

This issue was referenced by cacfaaa9a5

This issue was referenced by cacfaaa9a5114752daca709a19e85bb0ee5c26d3