Mesh: skip conversion from edit-mesh to mesh in edit-mode

This resolves a performance regression in 2.8x where every edit-mode
update performed an edit-mesh to mesh conversion.

Now the conversion will be lazily initialized if/when it's required.

New BKE_mesh_wrapper_* functions abstract over mesh data access.
Currently only edit-mesh and regular meshes are supported.
In the future sub-surface meshes may be supported too.

2 files changed, 54 insertions, 0 deletions

diff --git a/source/blender/bmesh/intern/bmesh_query.c b/source/blender/bmesh/intern/bmesh_query.c
index 64950411fed..e000b253000 100644
--- a/source/blender/bmesh/intern/bmesh_query.c
+++ b/source/blender/bmesh/intern/bmesh_query.c
@@ -1568,6 +1568,41 @@ float BM_loop_calc_face_normal_safe_ex(const BMLoop *l, const float epsilon_sq,
 }
 
 /**
+ * A version of BM_loop_calc_face_normal_safe_ex which takes vertex coordinates.
+ */
+float BM_loop_calc_face_normal_safe_vcos_ex(const BMLoop *l,
+                                            const float normal_fallback[3],
+                                            float const (*vertexCos)[3],
+                                            const float epsilon_sq,
+                                            float r_normal[3])
+{
+  const int i_prev = BM_elem_index_get(l->prev->v);
+  const int i_next = BM_elem_index_get(l->next->v);
+  const int i = BM_elem_index_get(l->v);
+
+  float v1[3], v2[3], v_tmp[3];
+  sub_v3_v3v3(v1, vertexCos[i_prev], vertexCos[i]);
+  sub_v3_v3v3(v2, vertexCos[i_next], vertexCos[i]);
+
+  const float fac = ((v2[0] == 0.0f) ?
+                         ((v2[1] == 0.0f) ? ((v2[2] == 0.0f) ? 0.0f : v1[2] / v2[2]) :
+                                            v1[1] / v2[1]) :
+                         v1[0] / v2[0]);
+
+  mul_v3_v3fl(v_tmp, v2, fac);
+  sub_v3_v3(v_tmp, v1);
+  if (fac != 0.0f && !is_zero_v3(v1) && len_squared_v3(v_tmp) > epsilon_sq) {
+    /* Not co-linear, we can compute cross-product and normalize it into normal. */
+    cross_v3_v3v3(r_normal, v1, v2);
+    return normalize_v3(r_normal);
+  }
+  else {
+    copy_v3_v3(r_normal, normal_fallback);
+    return 0.0f;
+  }
+}
+
+/**
  * #BM_loop_calc_face_normal_safe_ex with pre-defined sane epsilon.
  *
  * Since this doesn't scale based on triangle size, fixed value works well.
@@ -1577,6 +1612,15 @@ float BM_loop_calc_face_normal_safe(const BMLoop *l, float r_normal[3])
   return BM_loop_calc_face_normal_safe_ex(l, 1e-5f, r_normal);
 }
 
+float BM_loop_calc_face_normal_safe_vcos(const BMLoop *l,
+                                         const float normal_fallback[3],
+                                         float const (*vertexCos)[3],
+                                         float r_normal[3])
+
+{
+  return BM_loop_calc_face_normal_safe_vcos_ex(l, normal_fallback, vertexCos, 1e-5f, r_normal);
+}
+
 /**
  * \brief BM_loop_calc_face_normal
  *
diff --git a/source/blender/bmesh/intern/bmesh_query.h b/source/blender/bmesh/intern/bmesh_query.h
index aaf8191c5db..7e07059d4d8 100644
--- a/source/blender/bmesh/intern/bmesh_query.h
+++ b/source/blender/bmesh/intern/bmesh_query.h
@@ -142,6 +142,16 @@ float BM_loop_calc_face_normal(const BMLoop *l, float r_normal[3]) ATTR_NONNULL(
 float BM_loop_calc_face_normal_safe(const BMLoop *l, float r_normal[3]) ATTR_NONNULL();
 float BM_loop_calc_face_normal_safe_ex(const BMLoop *l, const float epsilon, float r_normal[3])
     ATTR_NONNULL();
+float BM_loop_calc_face_normal_safe_vcos_ex(const BMLoop *l,
+                                            const float normal_fallback[3],
+                                            float const (*vertexCos)[3],
+                                            const float epsilon_sq,
+                                            float r_normal[3]) ATTR_NONNULL();
+float BM_loop_calc_face_normal_safe_vcos(const BMLoop *l,
+                                         const float normal_fallback[3],
+                                         float const (*vertexCos)[3],
+                                         float r_normal[3]) ATTR_NONNULL();
+
 void BM_loop_calc_face_direction(const BMLoop *l, float r_normal[3]);
 void BM_loop_calc_face_tangent(const BMLoop *l, float r_tangent[3]);