60dd2cd7a8
The magnitude of the noise in the final output scales with: 1.0 - cogl_color_out.a A fixed value for the magnitude relative to cogl_color_out.a might be too small for large cogl_color_out.a or too large for small cogl_color_out.a (or possibly even both). Compensate for this to achieve constant magnitude in the final output. The coefficients were determined experimentally as a compromise between preventing colour banding with dark background content and tolerable noise with bright background content. This helps for the issue described in https://gitlab.gnome.org/GNOME/gnome-shell/-/issues/7795 . Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/3572>