Geometry Nodes: Add explicit Float to Int conversion node

This patch adds a very simple node that explicitly converts a float to
an int. While this may seem redundant, it would offer 2 benefits to the
current requirement to use implicit float conversions:
 1. It makes the node tree's intent more clear and self-documenting
    (especially if changes in the future require integer inputs).
 2. It eliminates undefined behavior in current/future nodes from float
    inputs by guaranteeing that the input is an integer.

The node offers a variety of rounding techniques to make it more flexible.

Differential Revision: https://developer.blender.org/D11700

2 files changed, 38 insertions, 0 deletions

diff --git a/source/blender/makesrna/RNA_enum_types.h b/source/blender/makesrna/RNA_enum_types.h
index 71af69f77a1..c8010a0e1ae 100644
--- a/source/blender/makesrna/RNA_enum_types.h
+++ b/source/blender/makesrna/RNA_enum_types.h
@@ -204,6 +204,7 @@ extern const EnumPropertyItem rna_enum_node_vec_math_items[];
 extern const EnumPropertyItem rna_enum_node_boolean_math_items[];
 extern const EnumPropertyItem rna_enum_node_float_compare_items[];
 extern const EnumPropertyItem rna_enum_node_filter_items[];
+extern const EnumPropertyItem rna_enum_node_float_to_int_items[];
 extern const EnumPropertyItem rna_enum_node_map_range_items[];
 extern const EnumPropertyItem rna_enum_node_clamp_items[];
 
diff --git a/source/blender/makesrna/intern/rna_nodetree.c b/source/blender/makesrna/intern/rna_nodetree.c
index d9e199e5eb2..93d5197f931 100644
--- a/source/blender/makesrna/intern/rna_nodetree.c
+++ b/source/blender/makesrna/intern/rna_nodetree.c
@@ -337,6 +337,31 @@ const EnumPropertyItem rna_enum_node_float_compare_items[] = {
     {0, NULL, 0, NULL, NULL},
 };
 
+const EnumPropertyItem rna_enum_node_float_to_int_items[] = {
+    {FN_NODE_FLOAT_TO_INT_ROUND,
+     "ROUND",
+     0,
+     "Round",
+     "Round the float up or down to the nearest integer"},
+    {FN_NODE_FLOAT_TO_INT_FLOOR,
+     "FLOOR",
+     0,
+     "Floor",
+     "Round the float down to the next smallest integer"},
+    {FN_NODE_FLOAT_TO_INT_CEIL,
+     "CEILING",
+     0,
+     "Ceiling",
+     "Round the float up to the next largest integer"},
+    {FN_NODE_FLOAT_TO_INT_TRUNCATE,
+     "TRUNCATE",
+     0,
+     "Truncate",
+     "Round the float to the closest integer in the direction of zero (floor if positive; ceiling "
+     "if negative)"},
+    {0, NULL, 0, NULL, NULL},
+};
+
 const EnumPropertyItem rna_enum_node_map_range_items[] = {
     {NODE_MAP_RANGE_LINEAR,
      "LINEAR",
@@ -4794,6 +4819,18 @@ static void def_float_compare(StructRNA *srna)
   RNA_def_property_update(prop, NC_NODE | NA_EDITED, "rna_Node_socket_update");
 }
 
+static void def_float_to_int(StructRNA *srna)
+{
+  PropertyRNA *prop;
+
+  prop = RNA_def_property(srna, "rounding_mode", PROP_ENUM, PROP_NONE);
+  RNA_def_property_enum_sdna(prop, NULL, "custom1");
+  RNA_def_property_enum_items(prop, rna_enum_node_float_to_int_items);
+  RNA_def_property_ui_text(
+      prop, "Rounding Mode", "Method used to convert the float to an integer");
+  RNA_def_property_update(prop, NC_NODE | NA_EDITED, "rna_Node_update");
+}
+
 static void def_vector_math(StructRNA *srna)
 {
   PropertyRNA *prop;