Attributes: Infrastructure for generic 8-bit integer data type

This commit adds infrastructure for 8 bit signed integer attributes.
This can be useful given the discussion in T94193, where we want to
store spline type, Bezier handle type, and other small enums as
attributes.

This is only exposed in the interface in the attribute lists, so it
shouldn't be an option in geometry nodes, at least for now.
I expect that this type won't be used directly very often, it
should mostly be cast to an enum type. However, with support
for 8 bit integers, it also makes sense to add things like mixing
implementations for consistency.

Differential Revision: https://developer.blender.org/D13721

1 files changed, 60 insertions, 0 deletions

diff --git a/source/blender/makesrna/intern/rna_attribute.c b/source/blender/makesrna/intern/rna_attribute.c
index 35da353a043..da835fb89c4 100644
--- a/source/blender/makesrna/intern/rna_attribute.c
+++ b/source/blender/makesrna/intern/rna_attribute.c
@@ -46,6 +46,7 @@ const EnumPropertyItem rna_enum_attribute_type_items[] = {
     {CD_PROP_STRING, "STRING", 0, "String", "Text string"},
     {CD_PROP_BOOL, "BOOLEAN", 0, "Boolean", "True or false"},
     {CD_PROP_FLOAT2, "FLOAT2", 0, "2D Vector", "2D vector with floating-point values"},
+    {CD_PROP_INT8, "INT8", 0, "8-Bit Integer", "Smaller integer with a range from -128 to 127"},
     {0, NULL, 0, NULL, NULL},
 };
 
@@ -59,6 +60,7 @@ const EnumPropertyItem rna_enum_attribute_type_with_auto_items[] = {
     {CD_PROP_STRING, "STRING", 0, "String", "Text string"},
     {CD_PROP_BOOL, "BOOLEAN", 0, "Boolean", "True or false"},
     {CD_PROP_FLOAT2, "FLOAT2", 0, "2D Vector", "2D vector with floating-point values"},
+    {CD_PROP_INT8, "INT8", 0, "8-Bit Integer", "Smaller integer with a range from -128 to 127"},
     {0, NULL, 0, NULL, NULL},
 };
 
@@ -133,6 +135,8 @@ static StructRNA *srna_by_custom_data_layer_type(const CustomDataType type)
       return &RNA_BoolAttribute;
     case CD_PROP_FLOAT2:
       return &RNA_Float2Attribute;
+    case CD_PROP_INT8:
+      return &RNA_ByteIntAttribute;
     default:
       return NULL;
   }
@@ -253,6 +257,9 @@ static void rna_Attribute_data_begin(CollectionPropertyIterator *iter, PointerRN
     case CD_PROP_FLOAT2:
       struct_size = sizeof(float[2]);
       break;
+    case CD_PROP_INT8:
+      struct_size = sizeof(int8_t);
+      break;
     default:
       struct_size = 0;
       length = 0;
@@ -294,6 +301,28 @@ static void rna_ByteColorAttributeValue_color_set(PointerRNA *ptr, const float *
   linearrgb_to_srgb_uchar4(&mlcol->r, values);
 }
 
+/* Int8 Attribute. */
+
+static int rna_ByteIntAttributeValue_get(PointerRNA *ptr)
+{
+  int8_t *value = (int8_t *)ptr->data;
+  return (int)(*value);
+}
+
+static void rna_ByteIntAttributeValue_set(PointerRNA *ptr, const int new_value)
+{
+  int8_t *value = (int8_t *)ptr->data;
+  if (new_value > INT8_MAX) {
+    *value = INT8_MAX;
+  }
+  else if (new_value < INT8_MIN) {
+    *value = INT8_MIN;
+  }
+  else {
+    *value = (int8_t)new_value;
+  }
+}
+
 /* Attribute Group */
 
 static PointerRNA rna_AttributeGroup_new(
@@ -648,6 +677,36 @@ static void rna_def_attribute_bool(BlenderRNA *brna)
   RNA_def_property_boolean_sdna(prop, NULL, "b", 0x01);
 }
 
+static void rna_def_attribute_int8(BlenderRNA *brna)
+{
+  StructRNA *srna;
+  PropertyRNA *prop;
+
+  srna = RNA_def_struct(brna, "ByteIntAttribute", "Attribute");
+  RNA_def_struct_sdna(srna, "CustomDataLayer");
+  RNA_def_struct_ui_text(srna, "8-bit Int Attribute", "8-bit int geometry attribute");
+
+  prop = RNA_def_property(srna, "data", PROP_COLLECTION, PROP_NONE);
+  RNA_def_property_struct_type(prop, "ByteIntAttributeValue");
+  RNA_def_property_collection_funcs(prop,
+                                    "rna_Attribute_data_begin",
+                                    "rna_iterator_array_next",
+                                    "rna_iterator_array_end",
+                                    "rna_iterator_array_get",
+                                    "rna_Attribute_data_length",
+                                    NULL,
+                                    NULL,
+                                    NULL);
+
+  srna = RNA_def_struct(brna, "ByteIntAttributeValue", NULL);
+  RNA_def_struct_sdna(srna, "MInt8Property");
+  RNA_def_struct_ui_text(
+      srna, "8-bit Integer Attribute Value", "8-bit value in geometry attribute");
+  prop = RNA_def_property(srna, "value", PROP_INT, PROP_NONE);
+  RNA_def_property_int_funcs(
+      prop, "rna_ByteIntAttributeValue_get", "rna_ByteIntAttributeValue_set", NULL);
+}
+
 static void rna_def_attribute_float2(BlenderRNA *brna)
 {
   StructRNA *srna;
@@ -723,6 +782,7 @@ static void rna_def_attribute(BlenderRNA *brna)
   rna_def_attribute_string(brna);
   rna_def_attribute_bool(brna);
   rna_def_attribute_float2(brna);
+  rna_def_attribute_int8(brna);
 }
 
 /* Mesh/PointCloud/Hair.attributes */