Previously, the spreadsheet editor could only show data of the original
and of the final evaluated object. Now it is possible to show the data
at some intermediate stages too.
For that the mode has to be set to "Node" in the spreadsheet editor.
Furthermore, the preview of a specific node has to be activated by
clicking the new icon in the header of geometry nodes.
The exact ui of this feature might be refined in upcoming commits.
It is already very useful for debugging node groups in it's current
state though.
Differential Revision: https://developer.blender.org/D10875
Currently the implementations specific to each geometry type are in
the same file. This makes it difficult to tell which code is generic
for all component types and which is specific to a certain type.
The two files, `attribute_access.cc`, and `geometry_set.cc` are
also getting quite long.
This commit splits up the implementation for every geometry component,
and adds an internal header file for the common parts of the attribute
access code. This was discussed with Jacques Lucke.