Patch to fix shading continuity.

Added it as extension to harden. Tried out different methods to fix normals,
Though as with width and segments changes shape, orientation of new polys
a non-smooth method of fix was not possible. Current method aggregates
vertex normals into a smooth fan without affecting edge shading.
Still need to fix the crease at new vertex edges

2 files changed, 103 insertions, 0 deletions

diff --git a/source/blender/bmesh/intern/bmesh_operators.h b/source/blender/bmesh/intern/bmesh_operators.h
index 1b5694c3ee8..9f6ac50a3e5 100644
--- a/source/blender/bmesh/intern/bmesh_operators.h
+++ b/source/blender/bmesh/intern/bmesh_operators.h
@@ -131,6 +131,7 @@ enum {
 	BEVEL_HN_NONE,
 	BEVEL_HN_FACE,
 	BEVEL_HN_ADJ,
+	BEVEL_HN_FIX_SHA,
 };
 
 extern const BMOpDefine *bmo_opdefines[];
diff --git a/source/blender/bmesh/tools/bmesh_bevel.c b/source/blender/bmesh/tools/bmesh_bevel.c
index 186d3a3c8e0..132436c70f0 100644
--- a/source/blender/bmesh/tools/bmesh_bevel.c
+++ b/source/blender/bmesh/tools/bmesh_bevel.c
@@ -44,6 +44,7 @@
 
 #include "BKE_customdata.h"
 #include "BKE_deform.h"
+#include "BKE_mesh.h"
 
 #include "eigen_capi.h"
 
@@ -1721,6 +1722,85 @@ static void bevel_harden_normals_mode(BMesh *bm, BevelParams *bp, BevVert *bv, B
 	} while (bcur != bstart);
 }
 
+static void bevel_fix_normal_shading_continuity(BevelParams *bp, BMesh *bm, BevVert *bv, GHash *faceHash)
+{
+	VMesh *vm = bv->vmesh;
+	BoundVert *bcur = bv->vmesh->boundstart, *start = bcur;
+	int ns = vm->seg;
+	int ns2 = ns / 2;
+	int count = 0;
+
+	BMFace *f;
+	BMLoop *l;
+	BMIter liter, fiter;
+
+	int cd_clnors_offset = CustomData_get_offset(&bm->ldata, CD_CUSTOMLOOPNORMAL);
+
+	BM_ITER_MESH(f, &fiter, bm, BM_FACES_OF_MESH) {
+
+		if (BLI_ghash_haskey(faceHash, f)) {
+			BM_ITER_ELEM(l, &liter, f, BM_LOOPS_OF_FACE) {
+				const int l_index = BM_elem_index_get(l);
+				short *clnors = BM_ELEM_CD_GET_VOID_P(l, cd_clnors_offset);
+				BKE_lnor_space_custom_normal_to_data(bm->lnor_spacearr->lspacearr[l_index], l->v->no, clnors);
+			}
+		}
+	}
+
+	do {
+		for (int i = 0; i <= ns; i++) {
+			BMVert *v1 = mesh_vert(vm, bcur->index, 0, i)->v, *v2;
+			BMEdge *e;
+			BMIter eiter;
+
+			BM_ITER_ELEM(e, &eiter, v1, BM_EDGES_OF_VERT) {
+				BMFace *f_a, *f_b;
+				BM_edge_face_pair(e, &f_a, &f_b);
+
+				bool _f_a = false, _f_b = false;
+				if (f_a)
+					_f_a = BLI_ghash_haskey(faceHash, f_a);
+				if (f_b)
+					_f_b = BLI_ghash_haskey(faceHash, f_b);
+				if (_f_a ^ _f_b) {
+
+					BM_ITER_ELEM(l, &liter, v1, BM_LOOPS_OF_VERT) {
+
+						if (l->f == f_a || l->f == f_b) {
+							const int l_index = BM_elem_index_get(l);
+							short *clnors = BM_ELEM_CD_GET_VOID_P(l, cd_clnors_offset);
+							float res[3];
+							copy_v3_v3(res, f_a->no);
+							add_v3_v3(res, f_b->no);
+							mul_v3_fl(res, 0.5f);
+							normalize_v3(res);
+
+							BKE_lnor_space_custom_normal_to_data(bm->lnor_spacearr->lspacearr[l_index], res, clnors);
+						}
+					}
+				}
+			}
+
+			float res_n[3];
+			zero_v3(res_n);
+			BM_ITER_ELEM(l, &liter, v1, BM_LOOPS_OF_VERT) {
+				if (!BLI_ghash_haskey(faceHash, l->f)) {
+					add_v3_v3(res_n, l->f->no);
+				}
+			}
+			normalize_v3(res_n);
+			BM_ITER_ELEM(l, &liter, v1, BM_LOOPS_OF_VERT) {
+				if (BLI_ghash_haskey(faceHash, l->f)) {
+					const int l_index = BM_elem_index_get(l);
+					short *clnors = BM_ELEM_CD_GET_VOID_P(l, cd_clnors_offset);
+					BKE_lnor_space_custom_normal_to_data(bm	->lnor_spacearr->lspacearr[l_index], res_n, clnors);
+				}
+			}
+		}
+		bcur = bcur->next;
+	} while (bcur != start);
+}
+
 /* Set the any_seam property for a BevVert and all its BoundVerts */
 static void set_bound_vert_seams(BevVert *bv, bool mark_seam, bool mark_sharp)
 {
@@ -5648,6 +5728,17 @@ void BM_mesh_bevel(
 			}
 		}
 
+		GHash *faceHash;
+		if (!bm->use_toolflags && bp.hnmode == BEVEL_HN_FIX_SHA) {
+			faceHash = BLI_ghash_ptr_new(__func__);
+			BMFace *f;
+			BM_ITER_MESH(f, &iter, bm, BM_FACES_OF_MESH) {
+				if (BM_elem_flag_test(f, BM_ELEM_TAG)) {
+					BLI_ghash_insert(faceHash, f, NULL);
+				}
+			}
+		}
+
 		/* Build polygons for edges */
 		if (!bp.vertex_only) {
 			BM_ITER_MESH (e, &iter, bm, BM_EDGES_OF_MESH) {
@@ -5664,6 +5755,7 @@ void BM_mesh_bevel(
 				bevel_harden_normals_mode(bm, &bp, bv, op);
 		}
 
+
 		/* Rebuild face polygons around affected vertices */
 		BM_ITER_MESH (v, &iter, bm, BM_VERTS_OF_MESH) {
 			if (BM_elem_flag_test(v, BM_ELEM_TAG)) {
@@ -5672,6 +5764,16 @@ void BM_mesh_bevel(
 			}
 		}
 
+		if (!bm->use_toolflags && bp.hnmode == BEVEL_HN_FIX_SHA) {
+			BM_mesh_normals_update(bm);
+			BM_lnorspace_update(bm);
+			GHASH_ITER(giter, bp.vert_hash) {
+				bv = BLI_ghashIterator_getValue(&giter);
+				if (!bm->use_toolflags)
+					bevel_fix_normal_shading_continuity(&bp, bm, bv, faceHash);
+			}
+			BLI_ghash_free(faceHash, NULL, NULL);
+		}
 
 		BM_ITER_MESH_MUTABLE (v, v_next, &iter, bm, BM_VERTS_OF_MESH) {
 			if (BM_elem_flag_test(v, BM_ELEM_TAG)) {