Geometry: add .attributes in the Python API for Mesh, Hair and Point Cloud

This puts all generic float/int/vector/color/string geometry attributes in a new
.attributes property. For meshes it provides a more general API for existing
attributes, for point clouds attributes will be used as an essential part of
particle nodes.

This patch was implemented by @lichtwerk, with further changes by me. It's
still a work in progress, but posting here to show what is going on and for
early feedback.

Ref T76659

Differential Revision: https://developer.blender.org/D8200

4 files changed, 12 insertions, 5 deletions

diff --git a/source/blender/makesdna/DNA_customdata_types.h b/source/blender/makesdna/DNA_customdata_types.h
index 2990fa85c27..51b233449bf 100644
--- a/source/blender/makesdna/DNA_customdata_types.h
+++ b/source/blender/makesdna/DNA_customdata_types.h
@@ -209,17 +209,17 @@ typedef enum CustomDataType {
 #define CD_MASK_PROP_FLOAT3 (1ULL << CD_PROP_FLOAT3)
 #define CD_MASK_PROP_FLOAT2 (1ULL << CD_PROP_FLOAT2)
 
-/** Data types that may be defined for all mesh elements types. */
-#define CD_MASK_GENERIC_DATA \
-  (CD_MASK_PROP_FLOAT | CD_MASK_PROP_INT32 | CD_MASK_PROP_STRING | CD_MASK_PROP_FLOAT3 | \
-   CD_MASK_PROP_FLOAT2)
-
 /** Multires loop data. */
 #define CD_MASK_MULTIRES_GRIDS (CD_MASK_MDISPS | CD_GRID_PAINT_MASK)
 
 /* All data layers. */
 #define CD_MASK_ALL (~0LL)
 
+/* All generic attributes. */
+#define CD_MASK_PROP_ALL \
+  (CD_MASK_PROP_FLOAT | CD_MASK_PROP_FLOAT2 | CD_MASK_PROP_FLOAT3 | CD_MASK_PROP_INT32 | \
+   CD_MASK_PROP_COLOR | CD_MASK_PROP_STRING | CD_MASK_MLOOPCOL)
+
 typedef struct CustomData_MeshMasks {
   uint64_t vmask;
   uint64_t emask;
diff --git a/source/blender/makesdna/DNA_hair_types.h b/source/blender/makesdna/DNA_hair_types.h
index d120e61cfef..27799560395 100644
--- a/source/blender/makesdna/DNA_hair_types.h
+++ b/source/blender/makesdna/DNA_hair_types.h
@@ -56,6 +56,8 @@ typedef struct Hair {
   /* Custom Data */
   struct CustomData pdata;
   struct CustomData cdata;
+  int attributes_active_index;
+  int _pad3;
 
   /* Material */
   struct Material **mat;
diff --git a/source/blender/makesdna/DNA_mesh_types.h b/source/blender/makesdna/DNA_mesh_types.h
index a6aef5b08ad..abfa3cc1b2e 100644
--- a/source/blender/makesdna/DNA_mesh_types.h
+++ b/source/blender/makesdna/DNA_mesh_types.h
@@ -191,6 +191,9 @@ typedef struct Mesh {
   int totpoly, totloop;
   /* END BMESH ONLY */
 
+  int attributes_active_index;
+  int _pad3;
+
   /* the last selected vertex/edge/face are used for the active face however
    * this means the active face must always be selected, this is to keep track
    * of the last selected face and is similar to the old active face flag where
diff --git a/source/blender/makesdna/DNA_pointcloud_types.h b/source/blender/makesdna/DNA_pointcloud_types.h
index d3b687c2c68..86cff098096 100644
--- a/source/blender/makesdna/DNA_pointcloud_types.h
+++ b/source/blender/makesdna/DNA_pointcloud_types.h
@@ -38,6 +38,8 @@ typedef struct PointCloud {
 
   /* Custom Data */
   struct CustomData pdata;
+  int attributes_active_index;
+  int _pad4;
 
   /* Material */
   struct Material **mat;