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

1 files changed, 82 insertions, 0 deletions

diff --git a/source/blender/blenkernel/BKE_attribute.h b/source/blender/blenkernel/BKE_attribute.h
new file mode 100644
index 00000000000..9eba13ef7c4
--- /dev/null
+++ b/source/blender/blenkernel/BKE_attribute.h
@@ -0,0 +1,82 @@
+/*
+ * 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.
+ *
+ * The Original Code is Copyright (C) 2006 Blender Foundation.
+ * All rights reserved.
+ */
+
+/** \file
+ * \ingroup bke
+ * \brief Generic geometry attributes built on CustomData.
+ */
+
+#pragma once
+
+#include "BLI_sys_types.h"
+
+#include "BKE_customdata.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+struct CustomData;
+struct CustomDataLayer;
+struct ID;
+struct PointerRNA;
+struct ReportList;
+
+/* Attribute.domain */
+typedef enum AttributeDomain {
+  ATTR_DOMAIN_VERTEX = 0,  /* Mesh Vertex */
+  ATTR_DOMAIN_EDGE = 1,    /* Mesh Edge */
+  ATTR_DOMAIN_CORNER = 2,  /* Mesh Corner */
+  ATTR_DOMAIN_POLYGON = 3, /* Mesh Polygon */
+
+  ATTR_DOMAIN_POINT = 4, /* Hair or PointCloud Point */
+  ATTR_DOMAIN_CURVE = 5, /* Hair Curve */
+
+  ATTR_DOMAIN_NUM
+} AttributeDomain;
+
+/* Attributes */
+
+struct CustomDataLayer *BKE_id_attribute_new(struct ID *id,
+                                             const char *name,
+                                             const int type,
+                                             const AttributeDomain domain,
+                                             struct ReportList *reports);
+void BKE_id_attribute_remove(struct ID *id,
+                             struct CustomDataLayer *layer,
+                             struct ReportList *reports);
+
+AttributeDomain BKE_id_attribute_domain(struct ID *id, struct CustomDataLayer *layer);
+int BKE_id_attribute_data_length(struct ID *id, struct CustomDataLayer *layer);
+bool BKE_id_attribute_rename(struct ID *id,
+                             struct CustomDataLayer *layer,
+                             const char *new_name,
+                             struct ReportList *reports);
+
+int BKE_id_attributes_length(struct ID *id, const CustomDataMask mask);
+
+struct CustomDataLayer *BKE_id_attributes_active_get(struct ID *id);
+void BKE_id_attributes_active_set(struct ID *id, struct CustomDataLayer *layer);
+int *BKE_id_attributes_active_index_p(struct ID *id);
+
+CustomData *BKE_id_attributes_iterator_next_domain(struct ID *id, struct CustomDataLayer *layers);
+
+#ifdef __cplusplus
+}
+#endif