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

2 files changed, 14 insertions, 11 deletions

diff --git a/source/blender/nodes/composite/nodes/node_composite_image.cc b/source/blender/nodes/composite/nodes/node_composite_image.cc
index d8852e9333f..b6bd263b150 100644
--- a/source/blender/nodes/composite/nodes/node_composite_image.cc
+++ b/source/blender/nodes/composite/nodes/node_composite_image.cc
@@ -457,8 +457,8 @@ class ImageOperation : public NodeOperation {
 
     update_image_frame_number();
 
-    for (const OutputSocketRef *output : node()->outputs()) {
-      compute_output(output->identifier());
+    for (const bNodeSocket *output : this->node()->output_sockets()) {
+      compute_output(output->identifier);
     }
   }
 
@@ -488,12 +488,12 @@ class ImageOperation : public NodeOperation {
   /* Allocate all needed outputs as invalid. This should be called when is_valid returns false. */
   void allocate_invalid()
   {
-    for (const OutputSocketRef *output : node()->outputs()) {
-      if (!should_compute_output(output->identifier())) {
+    for (const bNodeSocket *output : this->node()->output_sockets()) {
+      if (!should_compute_output(output->identifier)) {
         continue;
       }
 
-      Result &result = get_result(output->identifier());
+      Result &result = get_result(output->identifier);
       result.allocate_invalid();
     }
   }
@@ -594,7 +594,7 @@ class ImageOperation : public NodeOperation {
   const char *get_pass_name(StringRef identifier)
   {
     DOutputSocket output = node().output_by_identifier(identifier);
-    return static_cast<NodeImageLayer *>(output->bsocket()->storage)->pass_name;
+    return static_cast<NodeImageLayer *>(output->storage)->pass_name;
   }
 
   /* Get the index of the pass with the given name in the selected render layer's passes list
@@ -850,9 +850,9 @@ class RenderLayerOperation : public NodeOperation {
     alpha_result.unbind_as_image();
 
     /* Other output passes are not supported for now, so allocate them as invalid. */
-    for (const OutputSocketRef *output : node()->outputs()) {
-      if (output->identifier() != "Image" && output->identifier() != "Alpha") {
-        get_result(output->identifier()).allocate_invalid();
+    for (const bNodeSocket *output : this->node()->output_sockets()) {
+      if (!STREQ(output->identifier, "Image") && !STREQ(output->identifier, "Alpha")) {
+        get_result(output->identifier).allocate_invalid();
       }
     }
   }
diff --git a/source/blender/nodes/composite/nodes/node_composite_normal.cc b/source/blender/nodes/composite/nodes/node_composite_normal.cc
index f61ace01cfd..a1a6303e21b 100644
--- a/source/blender/nodes/composite/nodes/node_composite_normal.cc
+++ b/source/blender/nodes/composite/nodes/node_composite_normal.cc
@@ -51,9 +51,12 @@ class NormalShaderNode : public ShaderNode {
   }
 
   /* The vector value is stored in the default value of the output socket. */
-  float *get_vector_value()
+  const float *get_vector_value()
   {
-    return node().output_by_identifier("Normal")->default_value<bNodeSocketValueVector>()->value;
+    return node()
+        .output_by_identifier("Normal")
+        ->default_value_typed<bNodeSocketValueVector>()
+        ->value;
   }
 };