Fix Sharpen mesh filter in Multires

Instead of accumulating displacement for each vertex into the neighbors, accumulate the opposite displacement from each neighbor into the vertex. I think this is the same and it does not produce artifacts in Multires.

Reviewed By: sergey, brecht

Differential Revision: https://developer.blender.org/D7508

2 files changed, 11 insertions, 27 deletions

diff --git a/source/blender/editors/sculpt_paint/sculpt_filter_mesh.c b/source/blender/editors/sculpt_paint/sculpt_filter_mesh.c
index 58c9e1a569e..fd0f67f040a 100644
--- a/source/blender/editors/sculpt_paint/sculpt_filter_mesh.c
+++ b/source/blender/editors/sculpt_paint/sculpt_filter_mesh.c
@@ -132,7 +132,6 @@ void SCULPT_filter_cache_free(SculptSession *ss)
   MEM_SAFE_FREE(ss->filter_cache->automask);
   MEM_SAFE_FREE(ss->filter_cache->surface_smooth_laplacian_disp);
   MEM_SAFE_FREE(ss->filter_cache->sharpen_factor);
-  MEM_SAFE_FREE(ss->filter_cache->accum_disp);
   MEM_SAFE_FREE(ss->filter_cache);
 }
 
@@ -347,9 +346,18 @@ static void mesh_filter_task_cb(void *__restrict userdata,
         /* This filter can't work at full strength as it needs multiple iterations to reach a
          * stable state. */
         fade = clamp_f(fade, 0.0f, 0.5f);
+        float disp_sharpen[3] = {0.0f, 0.0f, 0.0f};
+
+        SculptVertexNeighborIter ni;
+        SCULPT_VERTEX_NEIGHBORS_ITER_BEGIN (ss, vd.index, ni) {
+          float disp_n[3];
+          sub_v3_v3v3(
+              disp_n, SCULPT_vertex_co_get(ss, ni.index), SCULPT_vertex_co_get(ss, vd.index));
+          mul_v3_fl(disp_n, ss->filter_cache->sharpen_factor[ni.index]);
+          add_v3_v3(disp_sharpen, disp_n);
+        }
+        SCULPT_VERTEX_NEIGHBORS_ITER_END(ni);
 
-        float disp_sharpen[3];
-        copy_v3_v3(disp_sharpen, ss->filter_cache->accum_disp[vd.index]);
         mul_v3_fl(disp_sharpen, 1.0f - ss->filter_cache->sharpen_factor[vd.index]);
 
         float disp_avg[3];
@@ -407,24 +415,6 @@ static void mesh_filter_sharpen_init_factors(SculptSession *ss)
   }
 }
 
-static void mesh_filter_sharpen_accumulate_displacement(SculptSession *ss)
-{
-  const int totvert = SCULPT_vertex_count_get(ss);
-  for (int i = 0; i < totvert; i++) {
-    zero_v3(ss->filter_cache->accum_disp[i]);
-  }
-  for (int i = 0; i < totvert; i++) {
-    SculptVertexNeighborIter ni;
-    SCULPT_VERTEX_NEIGHBORS_ITER_BEGIN (ss, i, ni) {
-      float disp_n[3];
-      sub_v3_v3v3(disp_n, SCULPT_vertex_co_get(ss, i), SCULPT_vertex_co_get(ss, ni.index));
-      mul_v3_fl(disp_n, ss->filter_cache->sharpen_factor[i]);
-      add_v3_v3(ss->filter_cache->accum_disp[ni.index], disp_n);
-    }
-    SCULPT_VERTEX_NEIGHBORS_ITER_END(ni);
-  }
-}
-
 static void mesh_filter_surface_smooth_displace_task_cb(
     void *__restrict userdata, const int i, const TaskParallelTLS *__restrict UNUSED(tls))
 {
@@ -487,10 +477,6 @@ static int sculpt_mesh_filter_modal(bContext *C, wmOperator *op, const wmEvent *
   bool needs_pmap = sculpt_mesh_filter_needs_pmap(filter_type, use_face_sets);
   BKE_sculpt_update_object_for_edit(depsgraph, ob, needs_pmap, false);
 
-  if (filter_type == MESH_FILTER_SHARPEN) {
-    mesh_filter_sharpen_accumulate_displacement(ss);
-  }
-
   SculptThreadedTaskData data = {
       .sd = sd,
       .ob = ob,
@@ -586,7 +572,6 @@ static int sculpt_mesh_filter_invoke(bContext *C, wmOperator *op, const wmEvent
   if (RNA_enum_get(op->ptr, "type") == MESH_FILTER_SHARPEN) {
     ss->filter_cache->sharpen_smooth_ratio = RNA_float_get(op->ptr, "sharpen_smooth_ratio");
     ss->filter_cache->sharpen_factor = MEM_mallocN(sizeof(float) * totvert, "sharpen factor");
-    ss->filter_cache->accum_disp = MEM_mallocN(3 * sizeof(float) * totvert, "orco");
 
     mesh_filter_sharpen_init_factors(ss);
   }
diff --git a/source/blender/editors/sculpt_paint/sculpt_intern.h b/source/blender/editors/sculpt_paint/sculpt_intern.h
index d7b221ae947..50808b04276 100644
--- a/source/blender/editors/sculpt_paint/sculpt_intern.h
+++ b/source/blender/editors/sculpt_paint/sculpt_intern.h
@@ -834,7 +834,6 @@ typedef struct FilterCache {
   /* Sharpen mesh filter. */
   float sharpen_smooth_ratio;
   float *sharpen_factor;
-  float (*accum_disp)[3];
 
   /* unmasked nodes */
   PBVHNode **nodes;