Blender Git Loki

Exposing customdata mask layer (CD_PAINT_MASK) to Python API

There are several more or less new customdata layers that currently cannot be accessed via Python (or some are exposed via BMesh API but not via Mesh API). This patch aims to expose one of those layers - CD_PAINT_MASK.
It'd be pretty useful for existing and future addons targeting sculpt workflow. Currently to get some access to the mask we employ a hackish approach via hiding/revealing masked vertices, this adds mode switches and doesn't allow to get actual mask values which could be useful if converted into vertex group weights for later use in e.g. modifiers. With this patch we'd be able to access mask data directly.

Reviewers: campbellbarton

Reviewed By: campbellbarton

Subscribers: radcapricorn

Projects: #bf_blender

Differential Revision: https://developer.blender.org/D782