Geometry Nodes: add namespace for every file

This puts all static functions in geometry node files into a new
namespace. This allows using unity build which can improve
compile times significantly (P2578).

* The name space name is derived from the file name. That makes
  it possible to write some tooling that checks the names later on.
  The file name extension (`cc`) is added to the namespace name as
  well. This also possibly simplifies tooling but also makes it more
  obvious that this namespace is specific to a file.
* In the register function of every node, I added a namespace alias
  `namespace file_ns = blender::nodes::node_geo_*_cc;`. This avoids
  some duplication of the file name and may also simplify tooling,
  because this line is easy to detect. The name `file_ns` stands for "file
  namespace" and also indicates that this namespace corresponds to
  the current file. In the beginning I used `node_ns` but `file_ns` is more
  generic which may make it more suitable when we want to use unity
  builds outside of the nodes modules in the future.
* Some node files contain code that is actually shared between
  different nodes. For now I left that code in the `blender::nodes`
  namespace and moved it to the top of the file (couldn't move it to
  the bottom in all cases, so I just moved it to the top everywhere).
  As a separate cleanup step, this shared code should actually be
  moved to a separate file.

Differential Revision: https://developer.blender.org/D13330

1 files changed, 6 insertions, 4 deletions

diff --git a/source/blender/nodes/geometry/nodes/node_geo_input_tangent.cc b/source/blender/nodes/geometry/nodes/node_geo_input_tangent.cc
index 49885f29d44..231f808a1e1 100644
--- a/source/blender/nodes/geometry/nodes/node_geo_input_tangent.cc
+++ b/source/blender/nodes/geometry/nodes/node_geo_input_tangent.cc
@@ -20,7 +20,7 @@
 
 #include "node_geometry_util.hh"
 
-namespace blender::nodes {
+namespace blender::nodes::node_geo_input_tangent_cc {
 
 static void geo_node_input_tangent_declare(NodeDeclarationBuilder &b)
 {
@@ -161,14 +161,16 @@ static void geo_node_input_tangent_exec(GeoNodeExecParams params)
   params.set_output("Tangent", std::move(tangent_field));
 }
 
-}  // namespace blender::nodes
+}  // namespace blender::nodes::node_geo_input_tangent_cc
 
 void register_node_type_geo_input_tangent()
 {
+  namespace file_ns = blender::nodes::node_geo_input_tangent_cc;
+
   static bNodeType ntype;
 
   geo_node_type_base(&ntype, GEO_NODE_INPUT_TANGENT, "Curve Tangent", NODE_CLASS_INPUT, 0);
-  ntype.geometry_node_execute = blender::nodes::geo_node_input_tangent_exec;
-  ntype.declare = blender::nodes::geo_node_input_tangent_declare;
+  ntype.geometry_node_execute = file_ns::geo_node_input_tangent_exec;
+  ntype.declare = file_ns::geo_node_input_tangent_declare;
   nodeRegisterType(&ntype);
 }