Nodes: Dynamic node class for Map Range node

This patch makes it possible to set the UI color of a node's
header bar and override the default from the node's typeinfo.

Currently the color is taken from the `.nclass`
member of the node's bNodeType->TypeInfo struct.
This is created once when registering the node.
The TypeInfo is used for both UI and non-UI functionality.
Since the TypeInfo is shared, the header bar for the node
can't be changed without changing all nodes of that type.

The Map Range node is shown as a `Converter` or blue color by default.
This patch allows this to be changed dynamically to `Vector` or purple.

This is done by adding a `ui_class` callback to node typeinfo struct.

Reviewed By: HooglyBoogly

Differential Revision: https://developer.blender.org/D13936

1 files changed, 3 insertions, 0 deletions

diff --git a/source/blender/blenkernel/BKE_node.h b/source/blender/blenkernel/BKE_node.h
index d583b5f0648..7ffa180b523 100644
--- a/source/blender/blenkernel/BKE_node.h
+++ b/source/blender/blenkernel/BKE_node.h
@@ -274,6 +274,9 @@ typedef struct bNodeType {
                     char *label,
                     int maxlen);
 
+  /** Optional override for node class, used for drawing node header. */
+  int (*ui_class)(const struct bNode *node);
+
   /** Called when the node is updated in the editor. */
   void (*updatefunc)(struct bNodeTree *ntree, struct bNode *node);
   /** Check and update if internal ID data has changed. */