clamping difference between OCIO 1 and 2?

Paul Miller

I noticed that using linear data with an sRGB view transform, if I adjust the exposure/gain using a Matrix/Offset transform, there seems to be clamping in OCIO 2 that wasn't present in 1. It doesn't clamp if I use a null/raw view transform. (see attached images).

This is using the default GPU processor.

Is this expected behavior?

code basically boils down to:

OCIO::DisplayTransformRcPtr transform = OCIO::DisplayTransform::Create();
OCIO::MatrixTransformRcPtr gainTransform = OCIO::MatrixTransform::Create();
// compute gain matrix/offset
OCIO::ConstProcessorRcPtr processor = config->getProcessor(transform);

I am still using CreateLegacyShaderDesc. Could it be that some of this math has moved into the LUT, and it's clamping there?

Doug Walker

Hi Paul,

We'd like to investigate the issue you found. Could you send us the config or the shader that it produced?

(Feel free to use Slack, if it's easier.)