From 47276b84701727c2f187c77f1ec502b4ca4963bd Mon Sep 17 00:00:00 2001
From: Jacques Lucke <jacques@blender.org>
Date: Tue, 23 Nov 2021 14:47:25 +0100
Subject: Geometry Nodes: reduce overhead when processing single values

Currently the geometry nodes evaluator always stores a field for every
type that supports it, even if it is just a single value. This results in a lot
of overhead when there are many sockets that just contain a single
value, which is often the case.

This introduces a new `ValueOrField<T>` type that is used by the geometry
nodes evaluator. Now a field will only be created when it is actually
necessary. See D13307 for more details. In extrem cases this can speed
up the evaluation 2-3x (those cases are probably never hit in practice
though, but it's good to get rid of unnecessary overhead nevertheless).

Differential Revision: https://developer.blender.org/D13307
---
 source/blender/nodes/NOD_geometry_exec.hh | 43 +++++++++++++++++++++----------
 1 file changed, 29 insertions(+), 14 deletions(-)

(limited to 'source/blender/nodes/NOD_geometry_exec.hh')

diff --git a/source/blender/nodes/NOD_geometry_exec.hh b/source/blender/nodes/NOD_geometry_exec.hh
index 700f32ee414..6b6e8a89240 100644
--- a/source/blender/nodes/NOD_geometry_exec.hh
+++ b/source/blender/nodes/NOD_geometry_exec.hh
@@ -59,6 +59,7 @@ using fn::GVArray;
 using fn::GVArray_GSpan;
 using fn::GVMutableArray;
 using fn::GVMutableArray_GSpan;
+using fn::ValueOrField;
 using geometry_nodes_eval_log::NodeWarningType;
 
 /**
@@ -129,7 +130,7 @@ class GeoNodeExecParams {
   }
 
   template<typename T>
-  static inline constexpr bool is_stored_as_field_v = std::is_same_v<T, float> ||
+  static inline constexpr bool is_field_base_type_v = std::is_same_v<T, float> ||
                                                       std::is_same_v<T, int> ||
                                                       std::is_same_v<T, bool> ||
                                                       std::is_same_v<T, ColorGeometry4f> ||
@@ -157,9 +158,15 @@ class GeoNodeExecParams {
    */
   template<typename T> T extract_input(StringRef identifier)
   {
-    if constexpr (is_stored_as_field_v<T>) {
-      Field<T> field = this->extract_input<Field<T>>(identifier);
-      return fn::evaluate_constant_field(field);
+    if constexpr (is_field_base_type_v<T>) {
+      ValueOrField<T> value_or_field = this->extract_input<ValueOrField<T>>(identifier);
+      return value_or_field.as_value();
+    }
+    else if constexpr (fn::is_field_v<T>) {
+      using BaseType = typename T::base_type;
+      ValueOrField<BaseType> value_or_field = this->extract_input<ValueOrField<BaseType>>(
+          identifier);
+      return value_or_field.as_field();
     }
     else {
 #ifdef DEBUG
@@ -186,9 +193,9 @@ class GeoNodeExecParams {
     Vector<GMutablePointer> gvalues = provider_->extract_multi_input(identifier);
     Vector<T> values;
     for (GMutablePointer gvalue : gvalues) {
-      if constexpr (is_stored_as_field_v<T>) {
-        const Field<T> field = gvalue.relocate_out<Field<T>>();
-        values.append(fn::evaluate_constant_field(field));
+      if constexpr (is_field_base_type_v<T>) {
+        const ValueOrField<T> value_or_field = gvalue.relocate_out<ValueOrField<T>>();
+        values.append(value_or_field.as_value());
       }
       else {
         values.append(gvalue.relocate_out<T>());
@@ -200,11 +207,16 @@ class GeoNodeExecParams {
   /**
    * Get the input value for the input socket with the given identifier.
    */
-  template<typename T> const T get_input(StringRef identifier) const
+  template<typename T> T get_input(StringRef identifier) const
   {
-    if constexpr (is_stored_as_field_v<T>) {
-      const Field<T> &field = this->get_input<Field<T>>(identifier);
-      return fn::evaluate_constant_field(field);
+    if constexpr (is_field_base_type_v<T>) {
+      ValueOrField<T> value_or_field = this->get_input<ValueOrField<T>>(identifier);
+      return value_or_field.as_value();
+    }
+    else if constexpr (fn::is_field_v<T>) {
+      using BaseType = typename T::base_type;
+      ValueOrField<BaseType> value_or_field = this->get_input<ValueOrField<BaseType>>(identifier);
+      return value_or_field.as_field();
     }
     else {
 #ifdef DEBUG
@@ -226,9 +238,12 @@ class GeoNodeExecParams {
   template<typename T> void set_output(StringRef identifier, T &&value)
   {
     using StoredT = std::decay_t<T>;
-    if constexpr (is_stored_as_field_v<StoredT>) {
-      this->set_output<Field<StoredT>>(identifier,
-                                       fn::make_constant_field<StoredT>(std::forward<T>(value)));
+    if constexpr (is_field_base_type_v<StoredT>) {
+      this->set_output(identifier, ValueOrField<StoredT>(std::forward<T>(value)));
+    }
+    else if constexpr (fn::is_field_v<StoredT>) {
+      using BaseType = typename StoredT::base_type;
+      this->set_output(identifier, ValueOrField<BaseType>(std::forward<T>(value)));
     }
     else {
       const CPPType &type = CPPType::get<StoredT>();
-- 
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