Multires: Fix Subdivide, Reshape and Apply Base

This change fixes artifacts produced by these operations.

On a technical aspect this is done by porting all of the operations
to the new subdivision surface implementation which ensures that
tangent space used to evaluate modifier and those operations is
exactly the same (before modifier will use new code and the operations
will still use an old one).

The next step is to get sculpting on a non-top level to work, and
that actually requires fixes in the undo system.

1 files changed, 72 insertions, 0 deletions

diff --git a/source/blender/blenkernel/intern/multires_reshape_ccg.c b/source/blender/blenkernel/intern/multires_reshape_ccg.c
new file mode 100644
index 00000000000..1f8c782ed46
--- /dev/null
+++ b/source/blender/blenkernel/intern/multires_reshape_ccg.c
@@ -0,0 +1,72 @@
+/*
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software  Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ *
+ * The Original Code is Copyright (C) 2020 Blender Foundation.
+ * All rights reserved.
+ */
+
+/** \file
+ * \ingroup bke
+ */
+
+#include "multires_reshape.h"
+
+#include <string.h>
+
+#include "BLI_utildefines.h"
+
+#include "BKE_ccg.h"
+#include "BKE_subdiv_ccg.h"
+
+bool multires_reshape_assign_final_coords_from_ccg(const MultiresReshapeContext *reshape_context,
+                                                   struct SubdivCCG *subdiv_ccg)
+{
+  CCGKey reshape_level_key;
+  BKE_subdiv_ccg_key(&reshape_level_key, subdiv_ccg, reshape_context->reshape.level);
+
+  const int reshape_grid_size = reshape_context->reshape.grid_size;
+  const float reshape_grid_size_1_inv = 1.0f / (((float)reshape_grid_size) - 1.0f);
+
+  int num_grids = subdiv_ccg->num_grids;
+  for (int grid_index = 0; grid_index < num_grids; ++grid_index) {
+    CCGElem *ccg_grid = subdiv_ccg->grids[grid_index];
+    for (int y = 0; y < reshape_grid_size; ++y) {
+      const float v = (float)y * reshape_grid_size_1_inv;
+      for (int x = 0; x < reshape_grid_size; ++x) {
+        const float u = (float)x * reshape_grid_size_1_inv;
+
+        GridCoord grid_coord;
+        grid_coord.grid_index = grid_index;
+        grid_coord.u = u;
+        grid_coord.v = v;
+
+        ReshapeGridElement grid_element = multires_reshape_grid_element_for_grid_coord(
+            reshape_context, &grid_coord);
+
+        BLI_assert(grid_element.displacement != NULL);
+        memcpy(grid_element.displacement,
+               CCG_grid_elem_co(&reshape_level_key, ccg_grid, x, y),
+               sizeof(float) * 3);
+
+        if (reshape_level_key.has_mask) {
+          BLI_assert(grid_element.mask != NULL);
+          *grid_element.mask = *CCG_grid_elem_mask(&reshape_level_key, ccg_grid, x, y);
+        }
+      }
+    }
+  }
+
+  return true;
+}