Fix T57620: display custom normals in Edit Mode.

Since it seems that CD_ORIGINDEX is not available for loops,
the only choice is to simply use the loop normals already
computed by depsgraph after evaluating modifiers.

This revealed a bug where the Auto Smooth settings would be lost
from the mesh after complex modifiers, or after edit mesh to mesh
conversion, so restoring them is needed to get correct results.

1 files changed, 22 insertions, 0 deletions

diff --git a/source/blender/blenkernel/intern/DerivedMesh.c b/source/blender/blenkernel/intern/DerivedMesh.c
index de2cd5603a6..abad99a4909 100644
--- a/source/blender/blenkernel/intern/DerivedMesh.c
+++ b/source/blender/blenkernel/intern/DerivedMesh.c
@@ -1151,6 +1151,14 @@ static void add_shapekey_layers(Mesh *me_dst, Mesh *me_src, Object *UNUSED(ob))
 	}
 }
 
+static void mesh_copy_autosmooth(Mesh *me, Mesh *me_orig)
+{
+	if (me_orig->flag & ME_AUTOSMOOTH) {
+		me->flag |= ME_AUTOSMOOTH;
+		me->smoothresh = me_orig->smoothresh;
+	}
+}
+
 static void mesh_calc_modifiers(
         struct Depsgraph *depsgraph, Scene *scene, Object *ob, float (*inputVertexCos)[3],
         int useDeform,
@@ -1460,6 +1468,8 @@ static void mesh_calc_modifiers(
 					}
 					deformedVerts = NULL;
 				}
+
+				mesh_copy_autosmooth(me, ob->data);
 			}
 
 			/* create an orco mesh in parallel */
@@ -1693,6 +1703,7 @@ static void editbmesh_calc_modifiers(
 
 	if (r_cage && cageIndex == -1) {
 		*r_cage = BKE_mesh_from_editmesh_with_coords_thin_wrap(em, dataMask, NULL);
+		mesh_copy_autosmooth(*r_cage, ob->data);
 	}
 
 	md = modifiers_getVirtualModifierList(ob, &virtualModifierData);
@@ -1769,6 +1780,8 @@ static void editbmesh_calc_modifiers(
 				me = BKE_mesh_from_bmesh_for_eval_nomain(em->bm, 0);
 				ASSERT_IS_VALID_MESH(me);
 
+				mesh_copy_autosmooth(me, ob->data);
+
 				if (deformedVerts) {
 					BKE_mesh_apply_vert_coords(me, deformedVerts);
 				}
@@ -1822,6 +1835,8 @@ static void editbmesh_calc_modifiers(
 					MEM_freeN(deformedVerts);
 					deformedVerts = NULL;
 				}
+
+				mesh_copy_autosmooth(me, ob->data);
 			}
 			me->runtime.deformed_only = false;
 		}
@@ -1843,6 +1858,7 @@ static void editbmesh_calc_modifiers(
 				*r_cage = BKE_mesh_from_editmesh_with_coords_thin_wrap(
 				        em, mask,
 				        deformedVerts ? MEM_dupallocN(deformedVerts) : NULL);
+				mesh_copy_autosmooth(*r_cage, ob->data);
 			}
 		}
 	}
@@ -1878,6 +1894,8 @@ static void editbmesh_calc_modifiers(
 		*r_final = BKE_mesh_from_editmesh_with_coords_thin_wrap(em, dataMask, deformedVerts);
 		deformedVerts = NULL;
 
+		mesh_copy_autosmooth(*r_final, ob->data);
+
 		/* In this case, we should never have weight-modifying modifiers in stack... */
 		if (do_init_statvis) {
 			editmesh_update_statvis_color(scene, ob);
@@ -1916,6 +1934,10 @@ static void editbmesh_calc_modifiers(
 	if (!do_loop_normals) {
 		BKE_mesh_ensure_normals_for_display(*r_final);
 
+		if (r_cage && *r_cage && (*r_cage != *r_final)) {
+			BKE_mesh_ensure_normals_for_display(*r_cage);
+		}
+
 		/* Some modifiers, like datatransfer, may generate those data, we do not want to keep them,
 		 * as they are used by display code when available (i.e. even if autosmooth is disabled). */
 		if (CustomData_has_layer(&(*r_final)->ldata, CD_NORMAL)) {