[Bf-blender-cvs] [0cb99641e14] soc-2019-adaptive-cloth: Cloth: start implementation of updating cloth with new vertices

[ishbosamiya]

Commit: 0cb99641e14db79a13476556544808cd6480fedd
Author: ishbosamiya
Date:   Fri Jun 14 20:53:15 2019 +0530
Branches: soc-2019-adaptive-cloth
https://developer.blender.org/rB0cb99641e14db79a13476556544808cd6480fedd

Cloth: start implementation of updating cloth with new vertices

Idea is to flag all the newly created vertices. After all of the remeshing, create a new Cloth and add all the flagged vertices as well, switch out old Cloth for new Cloth. This is done because it seems harder to update the Cloth every time a new vertex is formed, would be easier to flag those vertices in BMesh and update the Cloth after the fact.
Currently added support to find the new ClothVertex's values.
Some design via comments added.

===================================================================

M	source/blender/blenkernel/intern/cloth.c

===================================================================

diff --git a/source/blender/blenkernel/intern/cloth.c b/source/blender/blenkernel/intern/cloth.c
index 40e95a92662..7dff36ec19e 100644
--- a/source/blender/blenkernel/intern/cloth.c
+++ b/source/blender/blenkernel/intern/cloth.c
@@ -432,11 +432,43 @@ static void cloth_remeshing_init_bmesh(Object *ob, ClothModifierData *clmd, Mesh
   clmd->clothObject->bm = clmd->clothObject->bm_prev;
 }
 
+static void cloth_remeshing_update_cloth_object_mesh(ClothModifierData *clmd, Mesh *mesh)
+{
+  Cloth *cloth = clmd->clothObject;
+
+  /* We need to update Cloth only if number of verts change */
+  if (mesh_result->totvert == cloth->mvert_num) {
+    return;
+  }
+
+  Cloth *new_cloth = MEM_mallocN(sizeof(Cloth), "New Cloth Object");
+
+  /* copy most attributes from previous cloth data except verts, springs */
+
+  int new_vert_count = 0;
+  for (int i = 0; i < mesh_result->totvert; i++) {
+    MVert *mvert = &mesh_result->mvert[i];
+    if (mvert->flag & SELECT) {
+      new_vert_count++;
+    }
+  }
+
+  cloth->mvert_num = mesh_result->totvert;
+
+  /* Tag all verts as old */
+  BMVert *v;
+  BMIter iter;
+  BM_ITER_MESH (v, &iter, clmd->clothObject->bm, BM_VERTS_OF_MESH) {
+    BM_elem_flag_disable(v, BM_ELEM_SELECT);
+  }
+}
+
 static Mesh *cloth_remeshing_update_cloth_object_bmesh(Object *UNUSED(ob), ClothModifierData *clmd)
 {
   Mesh *mesh_result = NULL;
   CustomData_MeshMasks cddata_masks = cloth_remeshing_get_cd_mesh_masks();
   mesh_result = BKE_mesh_from_bmesh_for_eval_nomain(clmd->clothObject->bm, &cddata_masks);
+  cloth_remeshing_update_cloth_object_mesh(clmd, mesh);
   clmd->clothObject->bm_prev = BM_mesh_copy(clmd->clothObject->bm);
   BM_mesh_free(clmd->clothObject->bm);
   clmd->clothObject->bm = NULL;
@@ -546,6 +578,53 @@ static void cloth_remeshing_find_bad_edges(BMesh *bm,
   MEM_freeN(edge_pairs);
 }
 
+static ClothVertex cloth_remeshing_mean_cloth_vert(ClothVertex *v1, ClothVertex *v2)
+{
+  ClothVertex new_vert;
+  /* TODO(Ish): flags */
+  add_v3_v3v3(new_vert.v, v1->v, v2->v);
+  mul_v3_fl(new_vert.v, 0.5f);
+
+  add_v3_v3v3(new_vert.xconst, v1->xconst, v2->xconst);
+  mul_v3_fl(new_vert.xconst, 0.5f);
+
+  add_v3_v3v3(new_vert.x, v1->x, v2->x);
+  mul_v3_fl(new_vert.x, 0.5f);
+
+  add_v3_v3v3(new_vert.xold, v1->xold, v2->xold);
+  mul_v3_fl(new_vert.xold, 0.5f);
+
+  add_v3_v3v3(new_vert.tx, v1->tx, v2->tx);
+  mul_v3_fl(new_vert.tx, 0.5f);
+
+  add_v3_v3v3(new_vert.txold, v1->txold, v2->txold);
+  mul_v3_fl(new_vert.txold, 0.5f);
+
+  add_v3_v3v3(new_vert.tv, v1->tv, v2->tv);
+  mul_v3_fl(new_vert.tv, 0.5f);
+
+  add_v3_v3v3(new_vert.impulse, v1->impulse, v2->impulse);
+  mul_v3_fl(new_vert.impulse, 0.5f);
+
+  add_v3_v3v3(new_vert.xrest, v1->xrest, v2->xrest);
+  mul_v3_fl(new_vert.xrest, 0.5f);
+
+  add_v3_v3v3(new_vert.dcvel, v1->dcvel, v2->dcvel);
+  mul_v3_fl(new_vert.dcvel, 0.5f);
+
+  new_vert.mass = (v1->mass + v2->mass) * 0.5f;
+  new_vert.goal = (v1->goal + v2->goal) * 0.5f;
+  new_vert.impulse_count = (v1->impulse_count + v2->impulse_count) * 0.5f;
+  new_vert.avg_spring_len = (v1->avg_spring_len + v2->avg_spring_len) * 0.5f;
+  new_vert.struct_stiff = (v1->struct_stiff + v2->struct_stiff) * 0.5f;
+  new_vert.bend_stiff = (v1->bend_stiff + v2->bend_stiff) * 0.5f;
+  new_vert.shear_stiff = (v1->shear_stiff + v2->shear_stiff) * 0.5f;
+  new_vert.spring_count = (v1->spring_count + v2->spring_count) * 0.5f;
+  new_vert.shrink_factor = (v1->shrink_factor + v2->shrink_factor) * 0.5f;
+
+  return new_vert;
+}
+
 static BMVert *cloth_remeshing_split_edge_keep_triangles(BMesh *bm,
                                                          BMEdge *e,
                                                          BMVert *v,
@@ -737,7 +816,8 @@ static bool cloth_remeshing_split_edges(ClothModifierData *clmd, LinkNodePair *s
   BMEdge *e;
   for (int i = 0; i < num_bad_edges; i++) {
     e = bad_edges[i];
-    cloth_remeshing_split_edge_keep_triangles(bm, e, e->v1, 0.5);
+    BMVert *new_vert = cloth_remeshing_split_edge_keep_triangles(bm, e, e->v1, 0.5);
+    BM_elem_flag_enable(new_vert, BM_ELEM_SELECT);
   }
   MEM_freeN(bad_edges);
   return true;