Nodes: add node callback for extra info that is drawn above node

This allows nodes to show some extra information next to the node. This can be
useful for debugging and will likely also be used for the new Bake node (#115466).

Pull Request: https://projects.blender.org/blender/blender/pulls/115805

source/blender/blenkernel/BKE_node.h

@@ -100,6 +100,7 @@ class NodeDeclaration;
 class NodeDeclarationBuilder;
 class GatherAddNodeSearchParams;
 class GatherLinkSearchOpParams;
+class NodeExtraInfoParams;
 }  // namespace nodes
 namespace realtime_compositor {
 class Context;
@@ -130,6 +131,7 @@ using NodeGetCompositorOperationFunction = blender::realtime_compositor::NodeOpe
     *(*)(blender::realtime_compositor::Context &context, blender::nodes::DNode node);
 using NodeGetCompositorShaderNodeFunction =
     blender::realtime_compositor::ShaderNode *(*)(blender::nodes::DNode node);
+using NodeExtraInfoFunction = void (*)(blender::nodes::NodeExtraInfoParams &params);
 
 #else
 typedef void *NodeGetCompositorOperationFunction;
@@ -144,6 +146,7 @@ typedef void *SocketGetCPPTypeFunction;
 typedef void *SocketGetGeometryNodesCPPTypeFunction;
 typedef void *SocketGetGeometryNodesCPPValueFunction;
 typedef void *SocketGetCPPValueFunction;
+typedef void *NodeExtraInfoFunction;
 typedef struct CPPTypeHandle CPPTypeHandle;
 #endif
 
@@ -386,6 +389,9 @@ typedef struct bNodeType {
    */
   NodeGatherSocketLinkOperationsFunction gather_link_search_ops;
 
+  /** Get extra information that is drawn next to the node. */
+  NodeExtraInfoFunction get_extra_info;
+
   /** True when the node cannot be muted. */
   bool no_muting;
 

source/blender/editors/space_node/node_draw.cc

@@ -85,6 +85,7 @@
 #include "NOD_geometry_exec.hh"
 #include "NOD_geometry_nodes_log.hh"
 #include "NOD_node_declaration.hh"
+#include "NOD_node_extra_info.hh"
 #include "NOD_socket_declarations_geometry.hh"
 
 #include "FN_field.hh"
@@ -100,6 +101,7 @@ namespace geo_log = blender::nodes::geo_eval_log;
 using blender::bke::bNodeTreeZone;
 using blender::bke::bNodeTreeZones;
 using blender::ed::space_node::NestedTreePreviews;
+using blender::nodes::NodeExtraInfoRow;
 
 /**
  * This is passed to many functions which draw the node editor.
@@ -2491,16 +2493,6 @@ static std::string node_get_execution_time_label(TreeDrawContext &tree_draw_ctx,
   return stream.str() + " ms";
 }
 
-struct NodeExtraInfoRow {
-  std::string text;
-  int icon;
-  const char *tooltip = nullptr;
-
-  uiButToolTipFunc tooltip_fn = nullptr;
-  void *tooltip_fn_arg = nullptr;
-  void (*tooltip_fn_free_arg)(void *) = nullptr;
-};
-
 struct NamedAttributeTooltipArg {
   Map<StringRefNull, geo_log::NamedAttributeUsage> usage_by_attribute;
 };
@@ -2609,11 +2601,18 @@ static std::optional<NodeExtraInfoRow> node_get_accessed_attributes_row(
   return row_from_used_named_attribute(node_log->used_named_attributes);
 }
 
-static Vector<NodeExtraInfoRow> node_get_extra_info(TreeDrawContext &tree_draw_ctx,
+static Vector<NodeExtraInfoRow> node_get_extra_info(const bContext &C,
+                                                    TreeDrawContext &tree_draw_ctx,
                                                     const SpaceNode &snode,
                                                     const bNode &node)
 {
   Vector<NodeExtraInfoRow> rows;
+
+  if (node.typeinfo->get_extra_info) {
+    nodes::NodeExtraInfoParams params{rows, node, C};
+    node.typeinfo->get_extra_info(params);
+  }
+
   if (!(snode.edittree->type == NTREE_GEOMETRY)) {
     /* Currently geometry nodes are the only nodes to have extra infos per nodes. */
     return rows;
@@ -2754,13 +2753,14 @@ static void node_draw_extra_info_panel_back(const bNode &node, const rctf &extra
       &panel_back_rect, color, nullptr, 0.0f, color_outline, outline_width, BASIS_RAD);
 }
 
-static void node_draw_extra_info_panel(const Scene *scene,
+static void node_draw_extra_info_panel(const bContext &C,
                                        TreeDrawContext &tree_draw_ctx,
                                        const SpaceNode &snode,
                                        const bNode &node,
                                        ImBuf *preview,
                                        uiBlock &block)
 {
+  const Scene *scene = CTX_data_scene(&C);
   if (!(snode.overlay.flag & SN_OVERLAY_SHOW_OVERLAYS)) {
     return;
   }
@@ -2768,7 +2768,7 @@ static void node_draw_extra_info_panel(const Scene *scene,
     /* If the preview has an non-drawable size, just don't draw it. */
     preview = nullptr;
   }
-  Vector<NodeExtraInfoRow> extra_info_rows = node_get_extra_info(tree_draw_ctx, snode, node);
+  Vector<NodeExtraInfoRow> extra_info_rows = node_get_extra_info(C, tree_draw_ctx, snode, node);
   if (extra_info_rows.size() == 0 && !preview) {
     return;
   }
@@ -2879,7 +2879,7 @@ static void node_draw_basis(const bContext &C,
 
       if (previews_shader) {
         ImBuf *preview = node_preview_acquire_ibuf(ntree, *previews_shader, node);
-        node_draw_extra_info_panel(CTX_data_scene(&C), tree_draw_ctx, snode, node, preview, block);
+        node_draw_extra_info_panel(C, tree_draw_ctx, snode, node, preview, block);
         node_release_preview_ibuf(*previews_shader);
         drawn_with_previews = true;
       }
@@ -2888,14 +2888,14 @@ static void node_draw_basis(const bContext &C,
             BKE_node_instance_hash_lookup(previews_compo, key));
         if (preview_compositor) {
           node_draw_extra_info_panel(
-              CTX_data_scene(&C), tree_draw_ctx, snode, node, preview_compositor->ibuf, block);
+              C, tree_draw_ctx, snode, node, preview_compositor->ibuf, block);
           drawn_with_previews = true;
         }
       }
     }
 
     if (drawn_with_previews == false) {
-      node_draw_extra_info_panel(CTX_data_scene(&C), tree_draw_ctx, snode, node, nullptr, block);
+      node_draw_extra_info_panel(C, tree_draw_ctx, snode, node, nullptr, block);
     }
   }
 
@@ -3212,7 +3212,7 @@ static void node_draw_hidden(const bContext &C,
 
   const int color_id = node_get_colorid(tree_draw_ctx, node);
 
-  node_draw_extra_info_panel(nullptr, tree_draw_ctx, snode, node, nullptr, block);
+  node_draw_extra_info_panel(C, tree_draw_ctx, snode, node, nullptr, block);
 
   /* Shadow. */
   node_draw_shadow(snode, node, hiddenrad, 1.0f);
@@ -3694,7 +3694,7 @@ static void frame_node_draw(const bContext &C,
   /* Label and text. */
   frame_node_draw_label(tree_draw_ctx, ntree, node, snode);
 
-  node_draw_extra_info_panel(nullptr, tree_draw_ctx, snode, node, nullptr, block);
+  node_draw_extra_info_panel(C, tree_draw_ctx, snode, node, nullptr, block);
 
   UI_block_end(&C, &block);
   UI_block_draw(&C, &block);

source/blender/nodes/NOD_node_extra_info.hh

@@ -0,0 +1,27 @@
+/* SPDX-FileCopyrightText: 2005 Blender Authors
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later */
+
+#pragma once
+
+#include "UI_interface_c.hh"
+
+namespace blender::nodes {
+
+struct NodeExtraInfoRow {
+  std::string text;
+  int icon = 0;
+  const char *tooltip = nullptr;
+
+  uiButToolTipFunc tooltip_fn = nullptr;
+  void *tooltip_fn_arg = nullptr;
+  void (*tooltip_fn_free_arg)(void *) = nullptr;
+};
+
+struct NodeExtraInfoParams {
+  Vector<NodeExtraInfoRow> &rows;
+  const bNode &node;
+  const bContext &C;
+};
+
+}  // namespace blender::nodes