This matches us up more closely with what PlasmaMAX does and allows us
to really fix x-raying effects by properly forcing objects into the
correct render pass.
This commit includes some bonus improvements for animated parenting
situations that I discovered through sciencing the various MOUL and PotS
PRPs. Hopefully it all works as advertised.
I have also added some poll helpers to the idprops module so every time
we use an ID Datablock Property, we won't have to reinvent the wheel. I
also noticed that PointerProperties have to be a direct descendent of
`bpy.types.ID` otherwise Blender crashes. This kind of makes sense and
is not a huge issue to have to work around.
This effectively bumps the minimum requirement to Blender 2.79.
Furthermore, any blendfiles saved with ID Datablock properties will
crash earlier versions of Blender. You have been warned...
After approximately 24 hours of writing, rewriting, and cursing Blender,
this appears to be the most flexible way of magically upgrading our old
string properties to ID Datablock properties. The general hacky-ness is
due to limitations in Blender's API.
Here's how it works... In your property group (node, modifier, etc) you
will need to implement the classmethod `_idprop_mapping`. This will map
new ID Datablock property attribute names to old string property
attribute names. Further, you will need to implement the
`_idprop_sources` method. This will map string property attribute names
to a collection to fetch the ID from. If you have specific filtering
rules to follow, they can be implemented here :).
To ensure code sanity, any attempts to access string properties that
have been marked as converted will now fail with an AttributeError.
Happy haxxoring!