Add BMLog for efficiently storing changes to vertices and faces

The BMLog is an interface for storing undo/redo steps as a BMesh is
modified. It only stores changes to the BMesh, not full copies.

Currently it supports the following types of changes:
- Adding and removing vertices
- Adding and removing faces
- Moving vertices
- Setting vertex paint-mask values
- Setting vertex hflags

1 files changed, 102 insertions, 0 deletions

diff --git a/source/blender/bmesh/intern/bmesh_log.h b/source/blender/bmesh/intern/bmesh_log.h
new file mode 100644
index 00000000000..958ff340b43
--- /dev/null
+++ b/source/blender/bmesh/intern/bmesh_log.h
@@ -0,0 +1,102 @@
+/*
+ * ***** BEGIN GPL LICENSE BLOCK *****
+ *
+ * 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.
+ *
+ * ***** END GPL LICENSE BLOCK *****
+ */
+
+#ifndef __BMESH_LOG_H__
+#define __BMESH_LOG_H__
+
+/* The BMLog is an interface for storing undo/redo steps as a BMesh is
+ * modified. It only stores changes to the BMesh, not full copies.
+ *
+ * Currently it supports the following types of changes:
+ * 
+ * - Adding and removing vertices
+ * - Adding and removing faces
+ * - Moving vertices
+ * - Setting vertex paint-mask values
+ * - Setting vertex hflags
+ */
+
+struct BMFace;
+struct BMVert;
+struct BMesh;
+struct RangeTreeUInt;
+
+typedef struct BMLog BMLog;
+typedef struct BMLogEntry BMLogEntry;
+
+/* Allocate and initialize a new BMLog */
+BMLog *BM_log_create(BMesh *bm);
+
+/* Allocate and initialize a new BMLog using existing BMLogEntries */
+BMLog *BM_log_from_existing_entries_create(BMesh *bm, BMLogEntry *entry);
+
+/* Free all the data in a BMLog including the log itself */
+void BM_log_free(BMLog *log);
+
+/* Get the number of log entries */
+int BM_log_length(const BMLog *log);
+
+/* Apply a consistent ordering to BMesh vertices and faces */
+void BM_log_mesh_elems_reorder(BMesh *bm, BMLog *log);
+
+/* Start a new log entry and update the log entry list */
+BMLogEntry *BM_log_entry_add(BMLog *log);
+
+/* Remove an entry from the log */
+void BM_log_entry_drop(BMLogEntry *entry);
+
+/* Undo one BMLogEntry */
+void BM_log_undo(BMesh *bm, BMLog *log);
+
+/* Redo one BMLogEntry */
+void BM_log_redo(BMesh *bm, BMLog *log);
+
+/* Log a vertex before it is modified */
+void BM_log_vert_before_modified(BMesh *bm, BMLog *log, struct BMVert *v);
+
+/* Log a new vertex as added to the BMesh */
+void BM_log_vert_added(BMesh *bm, BMLog *log, struct BMVert *v);
+
+/* Log a new face as added to the BMesh */
+void BM_log_face_added(BMLog *log, struct BMFace *f);
+
+/* Log a vertex as removed from the BMesh */
+void BM_log_vert_removed(BMesh *bm, BMLog *log, struct BMVert *v);
+
+/* Log a face as removed from the BMesh */
+void BM_log_face_removed(BMLog *log, struct BMFace *f);
+
+/* Log all vertices/faces in the BMesh as added */
+void BM_log_all_added(BMesh *bm, BMLog *log);
+
+/* Log all vertices/faces in the BMesh as removed */
+void BM_log_before_all_removed(BMesh *bm, BMLog *log);
+
+/* Get the logged coordinates of a vertex */
+const float *BM_log_original_vert_co(BMLog *log, BMVert *v);
+
+/* Get the logged mask of a vertex */
+float BM_log_original_mask(BMLog *log, BMVert *v);
+
+/* For internal use only (unit testing) */
+BMLogEntry *BM_log_current_entry(BMLog *log);
+struct RangeTreeUInt *BM_log_unused_ids(BMLog *log);
+
+#endif