Fix T54686: objects don't occlude each other for edit-mesh select (part 2)

The previous fix 8a6414ed46f66, resolved selection picking but didn't
work for box/circle/lasso select.

- Add ED_select_buffer_utils.h for general select-buffer operations
  unrelated to edit-mesh.

- Circle select still needs to cache select-id's for each update.

3 files changed, 42 insertions, 0 deletions

diff --git a/source/blender/editors/include/ED_mesh.h b/source/blender/editors/include/ED_mesh.h
index 4e6bf7d4df5..75e0f05d088 100644
--- a/source/blender/editors/include/ED_mesh.h
+++ b/source/blender/editors/include/ED_mesh.h
@@ -152,6 +152,12 @@ struct BMElem *EDBM_select_id_bm_elem_get(struct EDBMSelectID_Context *sel_id_ct
                                           const uint sel_id,
                                           uint *r_base_index);
 
+uint EDBM_select_id_context_offset_for_object_elem(const struct EDBMSelectID_Context *sel_id_ctx,
+                                                   int base_index,
+                                                   char htype);
+
+uint EDBM_select_id_context_elem_len(const struct EDBMSelectID_Context *sel_id_ctx);
+
 void EDBM_select_mirrored(
     struct BMEditMesh *em, const int axis, const bool extend, int *r_totmirr, int *r_totfail);
 void EDBM_automerge(struct Scene *scene, struct Object *ob, bool update, const char hflag);
diff --git a/source/blender/editors/include/ED_select_buffer_utils.h b/source/blender/editors/include/ED_select_buffer_utils.h
new file mode 100644
index 00000000000..54e4cdb6e4f
--- /dev/null
+++ b/source/blender/editors/include/ED_select_buffer_utils.h
@@ -0,0 +1,35 @@
+/*
+ * 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.
+ */
+
+/** \file
+ * \ingroup editors
+ */
+
+#ifndef __ED_SELECT_BUFFER_UTILS_H__
+#define __ED_SELECT_BUFFER_UTILS_H__
+
+struct rcti;
+
+uint *ED_select_buffer_bitmap_from_rect(const uint bitmap_len, const struct rcti *rect);
+uint *ED_select_buffer_bitmap_from_circle(const uint bitmap_len,
+                                          const int center[2],
+                                          const int radius);
+uint *ED_select_buffer_bitmap_from_poly(const uint bitmap_len,
+                                        const int poly[][2],
+                                        const int poly_len,
+                                        const rcti *rect);
+
+#endif /* __ED_SELECT_BUFFER_UTILS_H__ */
diff --git a/source/blender/editors/include/ED_view3d.h b/source/blender/editors/include/ED_view3d.h
index 2b8f926fc2c..61d1670b88d 100644
--- a/source/blender/editors/include/ED_view3d.h
+++ b/source/blender/editors/include/ED_view3d.h
@@ -42,6 +42,7 @@ struct GPUFX;
 struct GPUFXSettings;
 struct GPUOffScreen;
 struct GPUViewport;
+struct ID;
 struct ImBuf;
 struct MVert;
 struct Main;