Transform/Snap: EditMesh/BKE_bvhutils API improvements

Separate the creation of trees from EditMesh from the creation of trees from DerivedMesh.
This was meant to simplify the API, but didn't work out so well.

`bvhtree_from_mesh_*` actually is working as `bvhtree_from_derivedmesh_*`.
This is inconsistent with the trees created from EditMesh. Since for create them does not use the DerivedMesh.

In such cases the dm is being used only to cache the tree in the struct DerivedMesh. What is immediately released once
bvhtree is being used in functions that change(tag) the DM cleaning the cache.

- Use a filter function so users of SnapObjectContext can define how edit-mesh elements are handled.
- Remove em_evil.
- bvhtree of EditMesh is now really cached in the snap functions.
- Code becomes organized and easier to maintain.

This is an important patch for future improvements in snapping functions.

1 files changed, 107 insertions, 0 deletions

diff --git a/source/blender/editors/include/ED_transform_snap_object_context.h b/source/blender/editors/include/ED_transform_snap_object_context.h
new file mode 100644
index 00000000000..e591a91a90f
--- /dev/null
+++ b/source/blender/editors/include/ED_transform_snap_object_context.h
@@ -0,0 +1,107 @@
+/*
+ * ***** 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 *****
+ */
+
+/** \file ED_transform_snap_object_context.h
+ *  \ingroup editors
+ */
+
+#ifndef __ED_TRANSFORM_SNAP_OBJECT_CONTEXT_H__
+#define __ED_TRANSFORM_SNAP_OBJECT_CONTEXT_H__
+
+struct BMVert;
+struct BMEdge;
+struct BMFace;
+
+struct Scene;
+struct Main;
+struct Object;
+struct ARegion;
+struct View3D;
+
+/* transform_snap_object.c */
+
+/* ED_transform_snap_object_*** API */
+struct SnapObjectParams {
+	int snap_select;  /* SnapSelect */
+	union {
+		unsigned int snap_to : 4;
+		/* snap_target_flag: Snap to vert/edge/face. */
+		unsigned int snap_to_flag : 4;
+	};
+	/* use editmode cage */
+	unsigned int use_object_edit : 1;
+	/* special context sensitive handling for the active object */
+	unsigned int use_object_active : 1;
+};
+
+enum {
+	SNAP_OBJECT_USE_CACHE = (1 << 0),
+};
+
+typedef struct SnapObjectContext SnapObjectContext;
+SnapObjectContext *ED_transform_snap_object_context_create(
+        struct Main *bmain, struct Scene *scene, int flag);
+SnapObjectContext *ED_transform_snap_object_context_create_view3d(
+        struct Main *bmain, struct Scene *scene, int flag,
+        /* extra args for view3d */
+        struct ARegion *ar, struct View3D *v3d);
+void ED_transform_snap_object_context_destroy(SnapObjectContext *sctx);
+
+/* callbacks to filter how snap works */
+void ED_transform_snap_object_context_set_editmesh_callbacks(
+        SnapObjectContext *sctx,
+        bool (*test_vert_fn)(struct BMVert *, void *user_data),
+        bool (*test_edge_fn)(struct BMEdge *, void *user_data),
+        bool (*test_face_fn)(struct BMFace *, void *user_data),
+        void *user_data);
+
+bool ED_transform_snap_object_project_ray_ex(
+        struct SnapObjectContext *sctx,
+        const struct SnapObjectParams *params,
+        const float ray_start[3], const float ray_normal[3], float *ray_depth,
+        /* return args */
+        float r_loc[3], float r_no[3], int *r_index,
+        struct Object **r_ob, float r_obmat[4][4]);
+bool ED_transform_snap_object_project_ray(
+        SnapObjectContext *sctx,
+        const float ray_origin[3], const float ray_direction[3], float *ray_dist,
+        float r_co[3], float r_no[3]);
+
+bool ED_transform_snap_object_project_view3d_ex(
+        struct SnapObjectContext *sctx,
+        const struct SnapObjectParams *params,
+        const float mval[2], float *dist_px,
+        float *ray_depth,
+        float r_loc[3], float r_no[3], int *r_index);
+bool ED_transform_snap_object_project_view3d(
+        struct SnapObjectContext *sctx,
+        const struct SnapObjectParams *params,
+        const float mval[2], float *dist_px,
+        float *ray_depth,
+        /* return args */
+        float r_loc[3], float r_no[3]);
+bool ED_transform_snap_object_project_view3d_mixed(
+        SnapObjectContext *sctx,
+        const struct SnapObjectParams *params,
+        const float mval_fl[2], float *dist_px,
+        bool use_depth,
+        float r_co[3], float r_no[3]);
+
+#endif  /* __ED_TRANSFORM_SNAP_OBJECT_CONTEXT_H__ */