multires_reshape_subdivide.cc

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/* SPDX-FileCopyrightText: 2020 Blender Authors
 *
 * SPDX-License-Identifier: GPL-2.0-or-later */
 
#include "MEM_guardedalloc.h"
 
#include "DNA_mesh_types.h"
#include "DNA_meshdata_types.h"
#include "DNA_modifier_types.h"
#include "DNA_scene_types.h"
 
#include "BKE_customdata.hh"
#include "BKE_mesh.hh"
#include "BKE_multires.hh"
#include "BKE_subsurf.hh"
#include "BLI_math_vector.h"
 
#include "multires_reshape.hh"
 
static void multires_subdivide_create_object_space_linear_grids(Mesh *mesh)
{
  using namespace blender;
  using namespace blender::bke;
  const Span<float3> positions = mesh->vert_positions();
  const blender::OffsetIndices faces = mesh->faces();
  const blender::Span<int> corner_verts = mesh->corner_verts();
 
  MDisps *mdisps = static_cast<MDisps *>(
      CustomData_get_layer_for_write(&mesh->corner_data, CD_MDISPS, mesh->corners_num));
  for (const int p : faces.index_range()) {
    const blender::IndexRange face = faces[p];
    const float3 face_center = mesh::face_center_calc(positions, corner_verts.slice(face));
    for (int l = 0; l < face.size(); l++) {
      const int loop_index = face[l];
 
      float(*disps)[3] = mdisps[loop_index].disps;
      mdisps[loop_index].totdisp = 4;
      mdisps[loop_index].level = 1;
 
      int prev_loop_index = l - 1 >= 0 ? loop_index - 1 : loop_index + face.size() - 1;
      int next_loop_index = l + 1 < face.size() ? loop_index + 1 : face.start();
 
      const int vert = corner_verts[loop_index];
      const int vert_next = corner_verts[next_loop_index];
      const int vert_prev = corner_verts[prev_loop_index];
 
      copy_v3_v3(disps[0], face_center);
      mid_v3_v3v3(disps[1], positions[vert], positions[vert_next]);
      mid_v3_v3v3(disps[2], positions[vert], positions[vert_prev]);
      copy_v3_v3(disps[3], positions[vert]);
    }
  }
}
 
void multires_subdivide_create_tangent_displacement_linear_grids(Object *object,
                                                                 MultiresModifierData *mmd)
{
  Mesh *coarse_mesh = static_cast<Mesh *>(object->data);
  multires_force_sculpt_rebuild(object);
 
  MultiresReshapeContext reshape_context;
 
  const int new_top_level = mmd->totlvl + 1;
 
  const bool has_mdisps = CustomData_has_layer(&coarse_mesh->corner_data, CD_MDISPS);
  if (!has_mdisps) {
    CustomData_add_layer(
        &coarse_mesh->corner_data, CD_MDISPS, CD_SET_DEFAULT, coarse_mesh->corners_num);
  }
 
  if (new_top_level == 1) {
    /* No MDISPS. Create new grids for level 1 using the edges mid point and face centers. */
    multires_reshape_ensure_grids(coarse_mesh, 1);
    multires_subdivide_create_object_space_linear_grids(coarse_mesh);
  }
 
  /* Convert the new grids to tangent displacement. */
  multires_set_tot_level(object, mmd, new_top_level);
 
  if (!multires_reshape_context_create_from_modifier(&reshape_context, object, mmd, new_top_level))
  {
    return;
  }
 
  multires_reshape_object_grids_to_tangent_displacement(&reshape_context);
  multires_reshape_context_free(&reshape_context);
}