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

9 files changed, 147 insertions, 0 deletions

diff --git a/source/blender/blenkernel/BKE_node.h b/source/blender/blenkernel/BKE_node.h
index a3387ab554e..d049510ef4d 100644
--- a/source/blender/blenkernel/BKE_node.h
+++ b/source/blender/blenkernel/BKE_node.h
@@ -1457,6 +1457,7 @@ int ntreeTexExecTree(struct bNodeTree *ntree,
 #define FN_NODE_RANDOM_FLOAT 1206
 #define FN_NODE_INPUT_VECTOR 1207
 #define FN_NODE_INPUT_STRING 1208
+#define FN_NODE_FLOAT_TO_INT 1209
 
 /** \} */
 
diff --git a/source/blender/blenkernel/intern/node.cc b/source/blender/blenkernel/intern/node.cc
index 293a1b2f69d..3345aff5db4 100644
--- a/source/blender/blenkernel/intern/node.cc
+++ b/source/blender/blenkernel/intern/node.cc
@@ -5105,6 +5105,7 @@ static void registerFunctionNodes()
 {
   register_node_type_fn_boolean_math();
   register_node_type_fn_float_compare();
+  register_node_type_fn_float_to_int();
   register_node_type_fn_input_string();
   register_node_type_fn_input_vector();
   register_node_type_fn_random_float();
diff --git a/source/blender/makesdna/DNA_node_types.h b/source/blender/makesdna/DNA_node_types.h
index 54bd792294f..f1ad41a4492 100644
--- a/source/blender/makesdna/DNA_node_types.h
+++ b/source/blender/makesdna/DNA_node_types.h
@@ -1688,6 +1688,14 @@ typedef enum FloatCompareOperation {
   NODE_FLOAT_COMPARE_NOT_EQUAL = 5,
 } FloatCompareOperation;
 
+/* Float to Int node operations. */
+typedef enum FloatToIntRoundingMode {
+  FN_NODE_FLOAT_TO_INT_ROUND = 0,
+  FN_NODE_FLOAT_TO_INT_FLOOR = 1,
+  FN_NODE_FLOAT_TO_INT_CEIL = 2,
+  FN_NODE_FLOAT_TO_INT_TRUNCATE = 3,
+} FloatToIntRoundingMode;
+
 /* Clamp node types. */
 enum {
   NODE_CLAMP_MINMAX = 0,
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;
diff --git a/source/blender/nodes/CMakeLists.txt b/source/blender/nodes/CMakeLists.txt
index 49e40060c0f..4d3eee51a27 100644
--- a/source/blender/nodes/CMakeLists.txt
+++ b/source/blender/nodes/CMakeLists.txt
@@ -134,6 +134,7 @@ set(SRC
 
   function/nodes/node_fn_boolean_math.cc
   function/nodes/node_fn_float_compare.cc
+  function/nodes/node_fn_float_to_int.cc
   function/nodes/node_fn_input_string.cc
   function/nodes/node_fn_input_vector.cc
   function/nodes/node_fn_random_float.cc
diff --git a/source/blender/nodes/NOD_function.h b/source/blender/nodes/NOD_function.h
index b31b5326d66..29f1a465491 100644
--- a/source/blender/nodes/NOD_function.h
+++ b/source/blender/nodes/NOD_function.h
@@ -22,6 +22,7 @@ extern "C" {
 
 void register_node_type_fn_boolean_math(void);
 void register_node_type_fn_float_compare(void);
+void register_node_type_fn_float_to_int(void);
 void register_node_type_fn_input_string(void);
 void register_node_type_fn_input_vector(void);
 void register_node_type_fn_random_float(void);
diff --git a/source/blender/nodes/NOD_static_types.h b/source/blender/nodes/NOD_static_types.h
index 1d906033128..4fe0dc2f20a 100644
--- a/source/blender/nodes/NOD_static_types.h
+++ b/source/blender/nodes/NOD_static_types.h
@@ -263,6 +263,7 @@ DefNode(TextureNode,    TEX_NODE_PROC+TEX_DISTNOISE, 0,                  "TEX_DI
 
 DefNode(FunctionNode, FN_NODE_BOOLEAN_MATH,  def_boolean_math,  "BOOLEAN_MATH",  BooleanMath,  "Boolean Math", "")
 DefNode(FunctionNode, FN_NODE_FLOAT_COMPARE, def_float_compare, "FLOAT_COMPARE", FloatCompare, "Float Compare", "")
+DefNode(FunctionNode, FN_NODE_FLOAT_TO_INT, def_float_to_int, "FLOAT_TO_INT", FloatToInt, "Float to Integer", "")
 DefNode(FunctionNode, FN_NODE_INPUT_STRING, def_fn_input_string, "INPUT_STRING", InputString, "String", "")
 DefNode(FunctionNode, FN_NODE_INPUT_VECTOR, def_fn_input_vector, "INPUT_VECTOR", InputVector, "Vector", "")
 DefNode(FunctionNode, FN_NODE_RANDOM_FLOAT, 0,                  "RANDOM_FLOAT", RandomFloat, "Random Float", "")
diff --git a/source/blender/nodes/function/nodes/node_fn_float_to_int.cc b/source/blender/nodes/function/nodes/node_fn_float_to_int.cc
new file mode 100644
index 00000000000..5bc60509b54
--- /dev/null
+++ b/source/blender/nodes/function/nodes/node_fn_float_to_int.cc
@@ -0,0 +1,96 @@
+/*
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ */
+
+#include <math.h>
+
+#include "BLI_listbase.h"
+#include "BLI_string.h"
+
+#include "RNA_enum_types.h"
+
+#include "UI_interface.h"
+#include "UI_resources.h"
+
+#include "node_function_util.hh"
+
+static bNodeSocketTemplate fn_node_float_to_int_in[] = {
+    {SOCK_FLOAT, N_("Float"), 0.0, 0.0, 0.0, 0.0, -FLT_MAX, FLT_MAX},
+    {-1, ""},
+};
+
+static bNodeSocketTemplate fn_node_float_to_int_out[] = {
+    {SOCK_INT, N_("Integer")},
+    {-1, ""},
+};
+
+static void fn_node_float_to_int_layout(uiLayout *layout, bContext *UNUSED(C), PointerRNA *ptr)
+{
+  uiItemR(layout, ptr, "rounding_mode", 0, "", ICON_NONE);
+}
+
+static void node_float_to_int_label(bNodeTree *UNUSED(ntree), bNode *node, char *label, int maxlen)
+{
+  const char *name;
+  bool enum_label = RNA_enum_name(rna_enum_node_float_to_int_items, node->custom1, &name);
+  if (!enum_label) {
+    name = "Unknown";
+  }
+  BLI_strncpy(label, IFACE_(name), maxlen);
+}
+
+static const blender::fn::MultiFunction &get_multi_function(bNode &bnode)
+{
+  static blender::fn::CustomMF_SI_SO<float, int> round_fn{"Round",
+                                                          [](float a) { return std::round(a); }};
+  static blender::fn::CustomMF_SI_SO<float, int> floor_fn{"Floor",
+                                                          [](float a) { return (int)floor(a); }};
+  static blender::fn::CustomMF_SI_SO<float, int> ceil_fn{"Ceiling",
+                                                         [](float a) { return (int)ceil(a); }};
+  static blender::fn::CustomMF_SI_SO<float, int> trunc_fn{"Truncate",
+                                                          [](float a) { return (int)trunc(a); }};
+
+  switch (static_cast<FloatToIntRoundingMode>(bnode.custom1)) {
+    case FN_NODE_FLOAT_TO_INT_ROUND:
+      return round_fn;
+    case FN_NODE_FLOAT_TO_INT_FLOOR:
+      return floor_fn;
+    case FN_NODE_FLOAT_TO_INT_CEIL:
+      return ceil_fn;
+    case FN_NODE_FLOAT_TO_INT_TRUNCATE:
+      return trunc_fn;
+  }
+
+  BLI_assert_unreachable();
+  return blender::fn::dummy_multi_function;
+}
+
+static void node_float_to_int_expand_in_mf_network(blender::nodes::NodeMFNetworkBuilder &builder)
+{
+  const blender::fn::MultiFunction &fn = get_multi_function(builder.bnode());
+  builder.set_matching_fn(fn);
+}
+
+void register_node_type_fn_float_to_int()
+{
+  static bNodeType ntype;
+
+  fn_node_type_base(&ntype, FN_NODE_FLOAT_TO_INT, "Float to Integer", NODE_CLASS_CONVERTOR, 0);
+  node_type_socket_templates(&ntype, fn_node_float_to_int_in, fn_node_float_to_int_out);
+  node_type_label(&ntype, node_float_to_int_label);
+  ntype.expand_in_mf_network = node_float_to_int_expand_in_mf_network;
+  ntype.draw_buttons = fn_node_float_to_int_layout;
+  nodeRegisterType(&ntype);
+}