postReference_darkRamp

A ramp of light from 0 at the left edge to 0.1 at the right: the dark gradient an undithered 8-bit display path bands on.

Drawn unlit by @builtin::shaders.referenceChart, so a picture of it is measured against the light its properties state. Part of the post-verification reference scenes (@builtin::scenes.postReference.*); @builtin::modules.postMetrics reads them.