1 files changed, 158 insertions, 0 deletions
diff --git a/source/blender/blenkernel/intern/multires_reshape_apply_base.c b/source/blender/blenkernel/intern/multires_reshape_apply_base.c
new file mode 100644
index 00000000000..e05b5bb3179
--- /dev/null
+++ b/source/blender/blenkernel/intern/multires_reshape_apply_base.c
@@ -0,0 +1,158 @@
+/*
+ * 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 "MEM_guardedalloc.h"
+
+#include "DNA_mesh_types.h"
+#include "DNA_meshdata_types.h"
+
+#include "BLI_math_vector.h"
+
+#include "BKE_mesh.h"
+#include "BKE_mesh_mapping.h"
+#include "BKE_subdiv_eval.h"
+
+void multires_reshape_apply_base_update_mesh_coords(MultiresReshapeContext *reshape_context)
+{
+  Mesh *base_mesh = reshape_context->base_mesh;
+  const int grid_size = reshape_context->top.grid_size;
+  const int grid_index = grid_size * grid_size - 1;
+  for (int i = 0; i < base_mesh->totloop; ++i) {
+    MDisps *displacement_grid = &reshape_context->mdisps[i];
+    const MLoop *loop = &base_mesh->mloop[i];
+    MVert *vert = &base_mesh->mvert[loop->v];
+    copy_v3_v3(vert->co, displacement_grid->disps[grid_index]);
+  }
+}
+
+/* Assumes no is normalized; return value's sign is negative if v is on the other side of the
+ * plane. */
+static float v3_dist_from_plane(float v[3], float center[3], float no[3])
+{
+  float s[3];
+  sub_v3_v3v3(s, v, center);
+  return dot_v3v3(s, no);
+}
+
+void multires_reshape_apply_base_refit_base_mesh(MultiresReshapeContext *reshape_context)
+{
+  Mesh *base_mesh = reshape_context->base_mesh;
+
+  MeshElemMap *pmap;
+  int *pmap_mem;
+  BKE_mesh_vert_poly_map_create(&pmap,
+                                &pmap_mem,
+                                base_mesh->mpoly,
+                                base_mesh->mloop,
+                                base_mesh->totvert,
+                                base_mesh->totpoly,
+                                base_mesh->totloop);
+
+  float(*origco)[3] = MEM_calloc_arrayN(
+      base_mesh->totvert, 3 * sizeof(float), "multires apply base origco");
+  for (int i = 0; i < base_mesh->totvert; i++) {
+    copy_v3_v3(origco[i], base_mesh->mvert[i].co);
+  }
+
+  for (int i = 0; i < base_mesh->totvert; i++) {
+    float avg_no[3] = {0, 0, 0}, center[3] = {0, 0, 0}, push[3];
+
+    /* Don't adjust vertices not used by at least one poly. */
+    if (!pmap[i].count) {
+      continue;
+    }
+
+    /* Find center. */
+    int tot = 0;
+    for (int j = 0; j < pmap[i].count; j++) {
+      const MPoly *p = &base_mesh->mpoly[pmap[i].indices[j]];
+
+      /* This double counts, not sure if that's bad or good. */
+      for (int k = 0; k < p->totloop; k++) {
+        const int vndx = base_mesh->mloop[p->loopstart + k].v;
+        if (vndx != i) {
+          add_v3_v3(center, origco[vndx]);
+          tot++;
+        }
+      }
+    }
+    mul_v3_fl(center, 1.0f / tot);
+
+    /* Find normal. */
+    for (int j = 0; j < pmap[i].count; j++) {
+      const MPoly *p = &base_mesh->mpoly[pmap[i].indices[j]];
+      MPoly fake_poly;
+      MLoop *fake_loops;
+      float(*fake_co)[3];
+      float no[3];
+
+      /* Set up poly, loops, and coords in order to call BKE_mesh_calc_poly_normal_coords(). */
+      fake_poly.totloop = p->totloop;
+      fake_poly.loopstart = 0;
+      fake_loops = MEM_malloc_arrayN(p->totloop, sizeof(MLoop), "fake_loops");
+      fake_co = MEM_malloc_arrayN(p->totloop, 3 * sizeof(float), "fake_co");
+
+      for (int k = 0; k < p->totloop; k++) {
+        const int vndx = base_mesh->mloop[p->loopstart + k].v;
+
+        fake_loops[k].v = k;
+
+        if (vndx == i) {
+          copy_v3_v3(fake_co[k], center);
+        }
+        else {
+          copy_v3_v3(fake_co[k], origco[vndx]);
+        }
+      }
+
+      BKE_mesh_calc_poly_normal_coords(&fake_poly, fake_loops, (const float(*)[3])fake_co, no);
+      MEM_freeN(fake_loops);
+      MEM_freeN(fake_co);
+
+      add_v3_v3(avg_no, no);
+    }
+    normalize_v3(avg_no);
+
+    /* Push vertex away from the plane. */
+    const float dist = v3_dist_from_plane(base_mesh->mvert[i].co, center, avg_no);
+    copy_v3_v3(push, avg_no);
+    mul_v3_fl(push, dist);
+    add_v3_v3(base_mesh->mvert[i].co, push);
+  }
+
+  MEM_freeN(origco);
+  MEM_freeN(pmap);
+  MEM_freeN(pmap_mem);
+
+  /* Vertices were moved around, need to update normals after all the vertices are updated
+   * Probably this is possible to do in the loop above, but this is rather tricky because
+   * we don't know all needed vertices' coordinates there yet. */
+  BKE_mesh_calc_normals(base_mesh);
+}
+
+void multires_reshape_apply_base_refine_subdiv(MultiresReshapeContext *reshape_context)
+{
+  BKE_subdiv_eval_update_from_mesh(reshape_context->subdiv, reshape_context->base_mesh, NULL);
+}