ID 372539 - GPU accelerated colorspace transform registration fails when using OCIO environment variable

Problem summary:

If you have the OCIO environmant variable set and you register some GPU colorspace transform overrides via the Python API they will fail to update any transforms live on the GPU.

Steps to reproduce:

1. Set the OCIO environment variable, on your system, to <path to mari install>/Media/Color/OpenColorIO/aces/config.ocio
2. Startup the Mari install used above and make sure the environment variable is set by bringing up the new project dialog and seeing the following:
   

   

3. Cancel the new project dialog.
4. Open the Python console palette in Mari and paste and execute the following:
   
   mari.ocio.setShaderTransformCode(
       'aces',
       'Utility - sRGB - Texture',
       'ACES - ACEScg',
       '    #Output = vec4(1.0, 0.0, 0.0, #Input.a);\n')
    
5. Create a new project.

Expected behaviour:

Once the project has finished loading you should see the model displayed in red.

Actual behaviour:

The model is displayed in mid-grey.

Workaround:

No known workaround.

Tested versions/platforms:

• 3.3 & 4.0 - Unaffected
• 3.4 & <= 4.1 - Affected

Customer version/platform:

Not supplied