Add Custom Loop Normals.

This is the core code for it, tools (datatransfer and modifier) will come in next commits).
RNA api is already there, though.

See the code for details, but basically, we define, for each 'smooth fan'
(which is a set of adjacent loops around a same vertex that are smooth, i.e. have a single same normal),
a 'loop normal space' (or lnor space), using auto-computed normal and relevant edges, and store
custom normal as two angular factors inside that space. This allows to have custom normals
'following' deformations of the geometry, and to only save two shorts per loop in new clnor CDLayer.

Normal manipulation (editing, mixing, interpolating, etc.) shall always happen with plain 3D vectors normals,
and be converted back into storage format at the end.

Clnor computation has also been threaded (at least for Mesh case, not for BMesh), since the process can
be rather heavy with high poly meshes.

Also, bumping subversion, and fix mess in 2.70 versioning code.

3 files changed, 70 insertions, 0 deletions

diff --git a/source/blender/editors/mesh/mesh_data.c b/source/blender/editors/mesh/mesh_data.c
index 152d055d239..30e9a85d083 100644
--- a/source/blender/editors/mesh/mesh_data.c
+++ b/source/blender/editors/mesh/mesh_data.c
@@ -57,6 +57,7 @@
 
 #include "ED_mesh.h"
 #include "ED_object.h"
+#include "ED_screen.h"
 #include "ED_uvedit.h"
 #include "ED_view3d.h"
 
@@ -838,6 +839,71 @@ void MESH_OT_customdata_clear_skin(wmOperatorType *ot)
 	ot->flag = OPTYPE_REGISTER | OPTYPE_UNDO;
 }
 
+/* Clear custom loop normals */
+static int mesh_customdata_custom_splitnormals_add_exec(bContext *C, wmOperator *UNUSED(op))
+{
+	Object *ob = ED_object_context(C);
+	Mesh *me = ob->data;
+
+	if (!BKE_mesh_has_custom_loop_normals(me)) {
+		CustomData *data = GET_CD_DATA(me, ldata);
+
+		if (me->edit_btmesh) {
+			BM_data_layer_add(me->edit_btmesh->bm, data, CD_CUSTOMLOOPNORMAL);
+		}
+		else {
+			CustomData_add_layer(data, CD_CUSTOMLOOPNORMAL, CD_DEFAULT, NULL, me->totloop);
+		}
+
+		DAG_id_tag_update(&me->id, 0);
+		WM_event_add_notifier(C, NC_GEOM | ND_DATA, me);
+
+		return OPERATOR_FINISHED;
+	}
+	return OPERATOR_CANCELLED;
+}
+
+void MESH_OT_customdata_custom_splitnormals_add(wmOperatorType *ot)
+{
+	/* identifiers */
+	ot->name = "Add Custom Split Normals Data";
+	ot->idname = "MESH_OT_customdata_custom_splitnormals_add";
+	ot->description = "Add a custom split normals layer, if none exists yet";
+
+	/* api callbacks */
+	ot->exec = mesh_customdata_custom_splitnormals_add_exec;
+	ot->poll = ED_operator_object_active_editable_mesh;
+
+	/* flags */
+	ot->flag = OPTYPE_REGISTER | OPTYPE_UNDO;
+}
+
+static int mesh_customdata_custom_splitnormals_clear_exec(bContext *C, wmOperator *UNUSED(op))
+{
+	Object *ob = ED_object_context(C);
+	Mesh *me = ob->data;
+
+	if (BKE_mesh_has_custom_loop_normals(me)) {
+		return mesh_customdata_clear_exec__internal(C, BM_LOOP, CD_CUSTOMLOOPNORMAL);
+	}
+	return OPERATOR_CANCELLED;
+}
+
+void MESH_OT_customdata_custom_splitnormals_clear(wmOperatorType *ot)
+{
+	/* identifiers */
+	ot->name = "Clear Custom Split Normals Data";
+	ot->idname = "MESH_OT_customdata_custom_splitnormals_clear";
+	ot->description = "Remove the custom split normals layer, if it exists";
+
+	/* api callbacks */
+	ot->exec = mesh_customdata_custom_splitnormals_clear_exec;
+	ot->poll = ED_operator_object_active_editable_mesh;
+
+	/* flags */
+	ot->flag = OPTYPE_REGISTER | OPTYPE_UNDO;
+}
+
 /************************** Add Geometry Layers *************************/
 
 void ED_mesh_update(Mesh *mesh, bContext *C, int calc_edges, int calc_tessface)
diff --git a/source/blender/editors/mesh/mesh_intern.h b/source/blender/editors/mesh/mesh_intern.h
index a794db62e3e..8f5ecaed524 100644
--- a/source/blender/editors/mesh/mesh_intern.h
+++ b/source/blender/editors/mesh/mesh_intern.h
@@ -238,6 +238,8 @@ void MESH_OT_vertex_color_remove(struct wmOperatorType *ot);
 /* no create_mask yet */
 void MESH_OT_customdata_clear_mask(struct wmOperatorType *ot);
 void MESH_OT_customdata_clear_skin(struct wmOperatorType *ot);
+void MESH_OT_customdata_custom_splitnormals_add(struct wmOperatorType *ot);
+void MESH_OT_customdata_custom_splitnormals_clear(struct wmOperatorType *ot);
 void MESH_OT_drop_named_image(struct wmOperatorType *ot);
 
 
diff --git a/source/blender/editors/mesh/mesh_ops.c b/source/blender/editors/mesh/mesh_ops.c
index 8146be7ee47..59d0de87de6 100644
--- a/source/blender/editors/mesh/mesh_ops.c
+++ b/source/blender/editors/mesh/mesh_ops.c
@@ -153,6 +153,8 @@ void ED_operatortypes_mesh(void)
 	WM_operatortype_append(MESH_OT_vertex_color_remove);
 	WM_operatortype_append(MESH_OT_customdata_clear_mask);
 	WM_operatortype_append(MESH_OT_customdata_clear_skin);
+	WM_operatortype_append(MESH_OT_customdata_custom_splitnormals_add);
+	WM_operatortype_append(MESH_OT_customdata_custom_splitnormals_clear);
 	WM_operatortype_append(MESH_OT_drop_named_image);
 
 	WM_operatortype_append(MESH_OT_edgering_select);