Sculpt: slight topology rake performance inprovement.

Produces almost the same result but takes in account all the edges instead
of only four, which gets rid of the need to select specific edges. Also,
added a check to prevent it from destroying boundaries.

Differential Revision: https://developer.blender.org/D5763

1 files changed, 37 insertions, 77 deletions

diff --git a/source/blender/editors/sculpt_paint/sculpt.c b/source/blender/editors/sculpt_paint/sculpt.c
index e89b1104720..b9d621fc1fb 100644
--- a/source/blender/editors/sculpt_paint/sculpt.c
+++ b/source/blender/editors/sculpt_paint/sculpt.c
@@ -2274,92 +2274,51 @@ static void bmesh_neighbor_average(float avg[3], BMVert *v)
   copy_v3_v3(avg, v->co);
 }
 
-/* For bmesh: average only the four most aligned (parallel and perpendicular) edges
- * relative to a direction. Naturally converges to a quad-like tessellation. */
+/* For bmesh: Average surrounding verts based on an orthogonality measure.
+ * Naturally converges to a quad-like structure. */
 static void bmesh_four_neighbor_average(float avg[3], float direction[3], BMVert *v)
 {
-  /* Logic for 3 or more is identical. */
-  const int vfcount = BM_vert_face_count_at_most(v, 3);
-
-  /* Don't modify corner vertices. */
-  if (vfcount < 2) {
-    copy_v3_v3(avg, v->co);
-    return;
-  }
-
-  /* Project the direction to the vertex normal and create an additional
-   * parallel vector. */
-  float dir_a[3], dir_b[3];
-  cross_v3_v3v3(dir_a, direction, v->no);
-  cross_v3_v3v3(dir_b, dir_a, v->no);
-
-  /* The four vectors which will be used for smoothing.
-   * Occasionally less than 4 verts match the requirements in that case
-   * use 'v' as fallback. */
-  BMVert *pos_a = v;
-  BMVert *neg_a = v;
-  BMVert *pos_b = v;
-  BMVert *neg_b = v;
-
-  float pos_score_a = 0.0f;
-  float neg_score_a = 0.0f;
-  float pos_score_b = 0.0f;
-  float neg_score_b = 0.0f;
-
-  BMIter liter;
-  BMLoop *l;
-
-  BM_ITER_ELEM (l, &liter, v, BM_LOOPS_OF_VERT) {
-    BMVert *adj_v[2] = {l->prev->v, l->next->v};
-
-    for (int i = 0; i < ARRAY_SIZE(adj_v); i++) {
-      BMVert *v_other = adj_v[i];
 
-      if (vfcount != 2 || BM_vert_face_count_at_most(v_other, 2) <= 2) {
-        float vec[3];
-        sub_v3_v3v3(vec, v_other->co, v->co);
-        normalize_v3(vec);
+  float avg_co[3] = {0, 0, 0};
+  float tot_co = 0;
 
-        /* The score is a measure of how orthogonal the edge is. */
-        float score = dot_v3v3(vec, dir_a);
+  BMIter eiter;
+  BMEdge *e;
 
-        if (score >= pos_score_a) {
-          pos_a = v_other;
-          pos_score_a = score;
-        }
-        else if (score < neg_score_a) {
-          neg_a = v_other;
-          neg_score_a = score;
-        }
-        /* The same scoring but for the perpendicular direction. */
-        score = dot_v3v3(vec, dir_b);
-
-        if (score >= pos_score_b) {
-          pos_b = v_other;
-          pos_score_b = score;
-        }
-        else if (score < neg_score_b) {
-          neg_b = v_other;
-          neg_score_b = score;
-        }
-      }
+  BM_ITER_ELEM (e, &eiter, v, BM_EDGES_OF_VERT) {
+    if (BM_edge_is_boundary(e)) {
+      copy_v3_v3(avg, v->co);
+      return;
     }
+    BMVert *v_other = (e->v1 == v) ? e->v2 : e->v1;
+    float vec[3];
+    sub_v3_v3v3(vec, v_other->co, v->co);
+    madd_v3_v3fl(vec, v->no, -dot_v3v3(vec, v->no));
+    normalize_v3(vec);
+
+    /* fac is a measure of how orthogonal or parallel the edge is
+     * relative to the direction */
+    float fac = dot_v3v3(vec, direction);
+    fac = fac * fac - 0.5f;
+    fac *= fac;
+    madd_v3_v3fl(avg_co, v_other->co, fac);
+    tot_co += fac;
   }
 
-  /* Average everything together. */
-  zero_v3(avg);
-  add_v3_v3(avg, pos_a->co);
-  add_v3_v3(avg, neg_a->co);
-  add_v3_v3(avg, pos_b->co);
-  add_v3_v3(avg, neg_b->co);
-  mul_v3_fl(avg, 0.25f);
+  /* In case vert has no Edge s */
+  if (tot_co > 0) {
+    mul_v3_v3fl(avg, avg_co, 1.0f / tot_co);
 
-  /* Preserve volume. */
-  float vec[3];
-  sub_v3_v3(avg, v->co);
-  mul_v3_v3fl(vec, v->no, dot_v3v3(avg, v->no));
-  sub_v3_v3(avg, vec);
-  add_v3_v3(avg, v->co);
+    /* Preserve volume. */
+    float vec[3];
+    sub_v3_v3(avg, v->co);
+    mul_v3_v3fl(vec, v->no, dot_v3v3(avg, v->no));
+    sub_v3_v3(avg, vec);
+    add_v3_v3(avg, v->co);
+  }
+  else {
+    zero_v3(avg);
+  }
 }
 
 /* Same logic as neighbor_average_mask(), but for bmesh rather than mesh */
@@ -2598,6 +2557,7 @@ static void do_topology_rake_bmesh_task_cb_ex(void *__restrict userdata,
   mul_v3_v3fl(
       tmp, ss->cache->sculpt_normal_symm, dot_v3v3(ss->cache->sculpt_normal_symm, direction));
   sub_v3_v3(direction, tmp);
+  normalize_v3(direction);
 
   /* Cancel if there's no grab data. */
   if (is_zero_v3(direction)) {