Nodes: Add Refract and Faceforward functions to Vector Maths nodes

Cycles, Eevee, OSL, Geo, Attribute

Based on outdated refract patch D6619 by @cubic_sloth

`refract` and `faceforward` are standard functions in GLSL, OSL and Godot shader languages.
Adding these functions provides Blender shader artists access to these standard functions.

Reviewed By: brecht

Differential Revision: https://developer.blender.org/D10622

1 files changed, 47 insertions, 2 deletions

diff --git a/source/blender/makesrna/intern/rna_nodetree.c b/source/blender/makesrna/intern/rna_nodetree.c
index 7fa67ad351f..3aba3e51217 100644
--- a/source/blender/makesrna/intern/rna_nodetree.c
+++ b/source/blender/makesrna/intern/rna_nodetree.c
@@ -224,6 +224,18 @@ const EnumPropertyItem rna_enum_node_vec_math_items[] = {
      0,
      "Reflect",
      "Reflect A around the normal B. B doesn't need to be normalized"},
+    {NODE_VECTOR_MATH_REFRACT,
+     "REFRACT",
+     0,
+     "Refract",
+     "For a given incident vector A, surface normal B and ratio of indices of refraction, Ior, "
+     "refract returns the refraction vector, R"},
+    {NODE_VECTOR_MATH_FACEFORWARD,
+     "FACEFORWARD",
+     0,
+     "Faceforward",
+     "Orients a vector A to point away from a surface B as defined by its normal C. "
+     "Returns (dot(B, C) < 0) ? A : -A"},
     {NODE_VECTOR_MATH_DOT_PRODUCT, "DOT_PRODUCT", 0, "Dot Product", "A dot B"},
     {0, "", ICON_NONE, NULL, NULL},
     {NODE_VECTOR_MATH_DISTANCE, "DISTANCE", 0, "Distance", "Distance between A and B"},
@@ -1961,7 +1973,7 @@ static const EnumPropertyItem *rna_GeometryNodeAttributeFill_type_itemf(bContext
 
 /**
  * This bit of ugly code makes sure the float / attribute option shows up instead of
- * vector / attribute if the node uses an operation that uses a float for input B.
+ * vector / attribute if the node uses an operation that uses a float for input B or C.
  */
 static const EnumPropertyItem *rna_GeometryNodeAttributeVectorMath_input_type_b_itemf(
     bContext *UNUSED(C), PointerRNA *ptr, PropertyRNA *UNUSED(prop), bool *r_free)
@@ -1994,6 +2006,37 @@ static const EnumPropertyItem *rna_GeometryNodeAttributeVectorMath_input_type_b_
   return item_array;
 }
 
+static const EnumPropertyItem *rna_GeometryNodeAttributeVectorMath_input_type_c_itemf(
+    bContext *UNUSED(C), PointerRNA *ptr, PropertyRNA *UNUSED(prop), bool *r_free)
+{
+  bNode *node = ptr->data;
+  NodeAttributeVectorMath *node_storage = (NodeAttributeVectorMath *)node->storage;
+
+  EnumPropertyItem *item_array = NULL;
+  int items_len = 0;
+  for (const EnumPropertyItem *item = rna_node_geometry_attribute_input_type_items_any;
+       item->identifier != NULL;
+       item++) {
+    if (item->value == GEO_NODE_ATTRIBUTE_INPUT_ATTRIBUTE) {
+      RNA_enum_item_add(&item_array, &items_len, item);
+    }
+    else if (item->value == GEO_NODE_ATTRIBUTE_INPUT_FLOAT) {
+      if (node_storage->operation == NODE_VECTOR_MATH_REFRACT) {
+        RNA_enum_item_add(&item_array, &items_len, item);
+      }
+    }
+    else if (item->value == GEO_NODE_ATTRIBUTE_INPUT_VECTOR) {
+      if (node_storage->operation != NODE_VECTOR_MATH_REFRACT) {
+        RNA_enum_item_add(&item_array, &items_len, item);
+      }
+    }
+  }
+  RNA_enum_item_end(&item_array, &items_len);
+
+  *r_free = true;
+  return item_array;
+}
+
 static void rna_GeometryNodeAttributeVectorMath_operation_update(Main *bmain,
                                                                  Scene *scene,
                                                                  PointerRNA *ptr)
@@ -8901,7 +8944,9 @@ static void def_geo_attribute_vector_math(StructRNA *srna)
 
   prop = RNA_def_property(srna, "input_type_c", PROP_ENUM, PROP_NONE);
   RNA_def_property_enum_bitflag_sdna(prop, NULL, "input_type_c");
-  RNA_def_property_enum_items(prop, rna_node_geometry_attribute_input_type_items_vector);
+  RNA_def_property_enum_items(prop, rna_node_geometry_attribute_input_type_items_any);
+  RNA_def_property_enum_funcs(
+      prop, NULL, NULL, "rna_GeometryNodeAttributeVectorMath_input_type_c_itemf");
   RNA_def_property_ui_text(prop, "Input Type C", "");
   RNA_def_property_update(prop, NC_NODE | NA_EDITED, "rna_Node_socket_update");
 }