Blender Git Loki

Geometry Nodes: simplify and deduplicate callbacks on sockets

This adds a layer of abstraction between the code calling callbacks
on sockets and the implementation of those callbacks.
This abstraction layer allows some sockets to not implement all
callbacks when those can be derived from some other callback.

Geometry Nodes: change "Node Tree" to "Node Group"

Geometry Nodes: initial support for evaluating geometry node groups

This is still very basic and does quite a few unnecessary computations.
Also the error handling is quite weak currently, so when invalid things are
connected, it will probably just crash.

Also the interface that individual nodes have to implement will have to change,
but the current solution is a good starting point.

Only the triangulate node is implemented for now.

Geometry Nodes: add an initial geometry class

Functions: add generic pointer class

This class represents a pointer whose type is only known at runtime.

Functions: add move operations to CPPType

Geometry Nodes: Add initial node definition for edge split

This is just based on rBa7dba81aab22, and contains no funcionality at all.

Merge branch 'master' into geometry-nodes

Nodes: add initial UI for Triangulate node

Merge branch 'master' into geometry-nodes

Nodes: improve dependency between modifier and node group

Nodes: support creating geometry node groups

Nodes: show header in geometry node editor

Modifiers: add node_tree to NodesModifierData

Modifiers: rename Simulation to Nodes modifier

Nodes: rename Simulation to Geometry node tree

Merge branch 'master' into geometry-nodes

Nodes: add geometry socket type

We still have to pick a color for this socket.

Ref T81848.