Geometry Nodes: support viewing field values in spreadsheet

The viewer node has been expanded to have a field input next to the
geometry input. When both are connected (by ctrl+shift clicking on a node)
the spreadsheet will show the evaluated field on the geometry.

The operator to link to the viewer has become a bit smarter. It automatically
detects if it should link to the geometry or field input. In the future some more
smartness could be added, such as automatically relinking the "right" geometry
when viewing a field.

Internally, there are two major changes:
* Refactor of what happens when ctrl+shift clicking on a node to link to
  a viewer. The behavior of the geometry nodes viewer is a bit more complex
  than that of the compositor viewers. The behavior in compositing nodes
  should not have changed. Any change should be reported as a bug (and then
  we can decide if it's worse than before or if it needs fixing).
*  Evaluation, display and caching of fields in the spreadsheet editor.

Differential Revision: https://developer.blender.org/D12938

1 files changed, 32 insertions, 6 deletions

diff --git a/source/blender/editors/space_spreadsheet/spreadsheet_data_source_geometry.hh b/source/blender/editors/space_spreadsheet/spreadsheet_data_source_geometry.hh
index d1b5dc6845e..6c88a94f585 100644
--- a/source/blender/editors/space_spreadsheet/spreadsheet_data_source_geometry.hh
+++ b/source/blender/editors/space_spreadsheet/spreadsheet_data_source_geometry.hh
@@ -28,12 +28,34 @@ struct bContext;
 
 namespace blender::ed::spreadsheet {
 
+/**
+ * Contains additional named columns that should be displayed that are not stored on the geometry
+ * directly. This is used for displaying the evaluated fields connected to a viewer node.
+ */
+class ExtraColumns {
+ private:
+  /** Maps column names to their data. The data is actually stored in the spreadsheet cache. */
+  Map<std::string, fn::GSpan> columns_;
+
+ public:
+  void add(std::string name, fn::GSpan data)
+  {
+    columns_.add(std::move(name), data);
+  }
+
+  void foreach_default_column_ids(
+      FunctionRef<void(const SpreadsheetColumnID &, bool is_extra)> fn) const;
+
+  std::unique_ptr<ColumnValues> get_column_values(const SpreadsheetColumnID &column_id) const;
+};
+
 class GeometryDataSource : public DataSource {
  private:
   Object *object_eval_;
   const GeometrySet geometry_set_;
   const GeometryComponent *component_;
   AttributeDomain domain_;
+  ExtraColumns extra_columns_;
 
   /* Some data is computed on the fly only when it is requested. Computing it does not change the
    * logical state of this data source. Therefore, the corresponding methods are const and need to
@@ -45,11 +67,13 @@ class GeometryDataSource : public DataSource {
   GeometryDataSource(Object *object_eval,
                      GeometrySet geometry_set,
                      const GeometryComponentType component_type,
-                     const AttributeDomain domain)
+                     const AttributeDomain domain,
+                     ExtraColumns extra_columns)
       : object_eval_(object_eval),
         geometry_set_(std::move(geometry_set)),
         component_(geometry_set_.get_component_for_read(component_type)),
-        domain_(domain)
+        domain_(domain),
+        extra_columns_(std::move(extra_columns))
   {
   }
 
@@ -62,7 +86,7 @@ class GeometryDataSource : public DataSource {
   void apply_selection_filter(MutableSpan<bool> rows_included) const;
 
   void foreach_default_column_ids(
-      FunctionRef<void(const SpreadsheetColumnID &)> fn) const override;
+      FunctionRef<void(const SpreadsheetColumnID &, bool is_extra)> fn) const override;
 
   std::unique_ptr<ColumnValues> get_column_values(
       const SpreadsheetColumnID &column_id) const override;
@@ -73,16 +97,18 @@ class GeometryDataSource : public DataSource {
 class InstancesDataSource : public DataSource {
   const GeometrySet geometry_set_;
   const InstancesComponent *component_;
+  ExtraColumns extra_columns_;
 
  public:
-  InstancesDataSource(GeometrySet geometry_set)
+  InstancesDataSource(GeometrySet geometry_set, ExtraColumns extra_columns)
       : geometry_set_(std::move(geometry_set)),
-        component_(geometry_set_.get_component_for_read<InstancesComponent>())
+        component_(geometry_set_.get_component_for_read<InstancesComponent>()),
+        extra_columns_(std::move(extra_columns))
   {
   }
 
   void foreach_default_column_ids(
-      FunctionRef<void(const SpreadsheetColumnID &)> fn) const override;
+      FunctionRef<void(const SpreadsheetColumnID &, bool is_extra)> fn) const override;
 
   std::unique_ptr<ColumnValues> get_column_values(
       const SpreadsheetColumnID &column_id) const override;