Nodes: move NodeTreeRef functionality into node runtime data

The purpose of `NodeTreeRef` was to speed up various queries on a read-only
`bNodeTree`. Not that we have runtime data in nodes and sockets, we can also
store the result of some queries there. This has some benefits:
* No need for a read-only separate node tree data structure which increased
  complexity.
* Makes it easier to reuse cached queries in more parts of Blender that can
  benefit from it.

A downside is that we loose some type safety that we got by having different
types for input and output sockets, as well as internal and non-internal links.

This patch also refactors `DerivedNodeTree` so that it does not use
`NodeTreeRef` anymore, but uses `bNodeTree` directly instead.

To provide a convenient API (that is also close to what `NodeTreeRef` has), a
new approach is implemented: `bNodeTree`, `bNode`, `bNodeSocket` and `bNodeLink`
now have C++ methods declared in `DNA_node_types.h` which are implemented in
`BKE_node_runtime.hh`. To make this work, `makesdna` now skips c++ sections when
parsing dna header files.

No user visible changes are expected.

Differential Revision: https://developer.blender.org/D15491

1 files changed, 1 insertions, 1 deletions

diff --git a/source/blender/nodes/function/nodes/node_fn_input_color.cc b/source/blender/nodes/function/nodes/node_fn_input_color.cc
index 46787f7575d..cdad1542c66 100644
--- a/source/blender/nodes/function/nodes/node_fn_input_color.cc
+++ b/source/blender/nodes/function/nodes/node_fn_input_color.cc
@@ -23,7 +23,7 @@ static void fn_node_input_color_layout(uiLayout *layout, bContext *UNUSED(C), Po
 static void fn_node_input_color_build_multi_function(
     blender::nodes::NodeMultiFunctionBuilder &builder)
 {
-  bNode &bnode = builder.node();
+  const bNode &bnode = builder.node();
   NodeInputColor *node_storage = static_cast<NodeInputColor *>(bnode.storage);
   blender::ColorGeometry4f color = (ColorGeometry4f)node_storage->color;
   builder.construct_and_set_matching_fn<blender::fn::CustomMF_Constant<ColorGeometry4f>>(color);