test2/source/blender/modifiers/intern/MOD_weighted_normal.cc

/* SPDX-FileCopyrightText: 2023 Blender Authors
 *
 * SPDX-License-Identifier: GPL-2.0-or-later */

/** \file
 * \ingroup modifiers
 */

#include "MEM_guardedalloc.h"

#include "BLI_array_utils.hh"
#include "BLI_math_vector.h"

#include "BLT_translation.hh"

#include "DNA_defaults.h"
#include "DNA_mesh_types.h"
#include "DNA_meshdata_types.h"
#include "DNA_screen_types.h"

#include "BKE_attribute.hh"
#include "BKE_context.hh"
#include "BKE_deform.hh"
#include "BKE_lib_id.hh"
#include "BKE_mesh.hh"
#include "BKE_screen.hh"

#include "UI_interface.hh"
#include "UI_resources.hh"

#include "RNA_access.hh"
#include "RNA_prototypes.hh"

#include "MOD_modifiertypes.hh"
#include "MOD_ui_common.hh"
#include "MOD_util.hh"

#include "bmesh.hh"

#define CLNORS_VALID_VEC_LEN (1e-6f)

struct ModePair {
  float val; /* Contains mode based value (face area / corner angle). */
  int index; /* Index value per face or per loop. */
};

/* Sorting function used in modifier, sorts in decreasing order. */
static int modepair_cmp_by_val_inverse(const void *p1, const void *p2)
{
  ModePair *r1 = (ModePair *)p1;
  ModePair *r2 = (ModePair *)p2;

  return (r1->val < r2->val) ? 1 : ((r1->val > r2->val) ? -1 : 0);
}

/* There will be one of those per vertex
 * (simple case, computing one normal per vertex), or per smooth fan. */
struct WeightedNormalDataAggregateItem {
  float normal[3];

  int loops_num;     /* Count number of loops using this item so far. */
  float curr_val;    /* Current max val for this item. */
  int curr_strength; /* Current max strength encountered for this item. */
};

#define NUM_CACHED_INVERSE_POWERS_OF_WEIGHT 128

struct WeightedNormalData {
  int verts_num;

  blender::Span<blender::float3> vert_positions;
  blender::Span<blender::float3> vert_normals;
  blender::Span<blender::int2> edges;
  blender::MutableSpan<bool> sharp_edges;

  blender::Span<int> corner_verts;
  blender::Span<int> corner_edges;
  blender::Span<int> loop_to_face;
  blender::MutableSpan<blender::short2> clnors;

  blender::OffsetIndices<int> faces;
  blender::Span<blender::float3> face_normals;
  blender::VArraySpan<bool> sharp_faces;
  const int *face_strength;

  const MDeformVert *dvert;
  int defgrp_index;
  bool use_invert_vgroup;

  float weight;
  short mode;

  /* Lower-level, internal processing data. */
  float cached_inverse_powers_of_weight[NUM_CACHED_INVERSE_POWERS_OF_WEIGHT];

  blender::Span<WeightedNormalDataAggregateItem> items_data;

  ModePair *mode_pair;
};

/**
 * Check strength of given face compared to those found so far for that given item
 * (vertex or smooth fan), and reset matching item_data in case we get a stronger new strength.
 */
static bool check_item_face_strength(WeightedNormalData *wn_data,
                                     WeightedNormalDataAggregateItem *item_data,
                                     const int face_index)
{
  BLI_assert(wn_data->face_strength != nullptr);

  const int mp_strength = wn_data->face_strength[face_index];

  if (mp_strength > item_data->curr_strength) {
    item_data->curr_strength = mp_strength;
    item_data->curr_val = 0.0f;
    item_data->loops_num = 0;
    zero_v3(item_data->normal);
  }

  return mp_strength == item_data->curr_strength;
}

static void aggregate_item_normal(WeightedNormalModifierData *wnmd,
                                  WeightedNormalData *wn_data,
                                  WeightedNormalDataAggregateItem *item_data,
                                  const int mv_index,
                                  const int face_index,
                                  const float curr_val,
                                  const bool use_face_influence)
{
  const blender::Span<blender::float3> face_normals = wn_data->face_normals;

  const MDeformVert *dvert = wn_data->dvert;
  const int defgrp_index = wn_data->defgrp_index;
  const bool use_invert_vgroup = wn_data->use_invert_vgroup;

  const float weight = wn_data->weight;

  float *cached_inverse_powers_of_weight = wn_data->cached_inverse_powers_of_weight;

  const bool has_vgroup = dvert != nullptr;
  const bool vert_of_group = has_vgroup &&
                             BKE_defvert_find_index(&dvert[mv_index], defgrp_index) != nullptr;

  if (has_vgroup &&
      ((vert_of_group && use_invert_vgroup) || (!vert_of_group && !use_invert_vgroup)))
  {
    return;
  }

  if (use_face_influence && !check_item_face_strength(wn_data, item_data, face_index)) {
    return;
  }

  /* If item's curr_val is 0 init it to present value. */
  if (item_data->curr_val == 0.0f) {
    item_data->curr_val = curr_val;
  }
  if (!compare_ff(item_data->curr_val, curr_val, wnmd->thresh)) {
    /* item's curr_val and present value differ more than threshold, update. */
    item_data->loops_num++;
    item_data->curr_val = curr_val;
  }

  /* Exponentially divided weight for each normal
   * (since a few values will be used by most cases, we cache those). */
  const int loops_num = item_data->loops_num;
  if (loops_num < NUM_CACHED_INVERSE_POWERS_OF_WEIGHT &&
      cached_inverse_powers_of_weight[loops_num] == 0.0f)
  {
    cached_inverse_powers_of_weight[loops_num] = 1.0f / powf(weight, loops_num);
  }
  const float inverted_n_weight = loops_num < NUM_CACHED_INVERSE_POWERS_OF_WEIGHT ?
                                      cached_inverse_powers_of_weight[loops_num] :
                                      1.0f / powf(weight, loops_num);

  madd_v3_v3fl(item_data->normal, face_normals[face_index], curr_val * inverted_n_weight);
}

static void apply_weights_vertex_normal(WeightedNormalModifierData *wnmd,
                                        WeightedNormalData *wn_data)
{
  using namespace blender;
  const int verts_num = wn_data->verts_num;

  const blender::Span<blender::float3> positions = wn_data->vert_positions;
  const blender::Span<int2> edges = wn_data->edges;
  const blender::OffsetIndices faces = wn_data->faces;
  const blender::Span<int> corner_verts = wn_data->corner_verts;
  const blender::Span<int> corner_edges = wn_data->corner_edges;

  MutableSpan<short2> clnors = wn_data->clnors;
  const blender::Span<int> loop_to_face = wn_data->loop_to_face;

  const blender::Span<blender::float3> face_normals = wn_data->face_normals;
  const int *face_strength = wn_data->face_strength;

  const MDeformVert *dvert = wn_data->dvert;

  const short mode = wn_data->mode;
  ModePair *mode_pair = wn_data->mode_pair;

  bke::mesh::CornerNormalSpaceArray lnors_spacearr;

  const bool keep_sharp = (wnmd->flag & MOD_WEIGHTEDNORMAL_KEEP_SHARP) != 0;
  const bool use_face_influence = (wnmd->flag & MOD_WEIGHTEDNORMAL_FACE_INFLUENCE) != 0 &&
                                  face_strength != nullptr;
  const bool has_vgroup = dvert != nullptr;

  blender::Array<blender::float3> corner_normals;

  Array<WeightedNormalDataAggregateItem> items_data;
  if (keep_sharp) {
    /* This will give us loop normal spaces,
     * we do not actually care about computed corner_normals for now... */
    corner_normals.reinitialize(corner_verts.size());
    bke::mesh::normals_calc_corners(positions,
                                    edges,
                                    faces,
                                    corner_verts,
                                    corner_edges,
                                    loop_to_face,
                                    wn_data->face_normals,
                                    wn_data->sharp_edges,
                                    wn_data->sharp_faces,
                                    clnors,
                                    &lnors_spacearr,
                                    corner_normals);

    WeightedNormalDataAggregateItem start_item{};
    start_item.curr_strength = FACE_STRENGTH_WEAK;
    items_data = Array<WeightedNormalDataAggregateItem>(lnors_spacearr.spaces.size(), start_item);
  }
  else {
    WeightedNormalDataAggregateItem start_item{};
    start_item.curr_strength = FACE_STRENGTH_WEAK;
    items_data = Array<WeightedNormalDataAggregateItem>(verts_num, start_item);
    lnors_spacearr.corner_space_indices.reinitialize(corner_verts.size());
    array_utils::fill_index_range<int>(lnors_spacearr.corner_space_indices);
  }
  wn_data->items_data = items_data;

  switch (mode) {
    case MOD_WEIGHTEDNORMAL_MODE_FACE:
      for (const int i : faces.index_range()) {
        const int face_index = mode_pair[i].index;
        const float mp_val = mode_pair[i].val;

        for (const int corner : faces[face_index]) {
          const int mv_index = corner_verts[corner];
          const int space_index = lnors_spacearr.corner_space_indices[corner];

          WeightedNormalDataAggregateItem *item_data = keep_sharp ? &items_data[space_index] :
                                                                    &items_data[mv_index];

          aggregate_item_normal(
              wnmd, wn_data, item_data, mv_index, face_index, mp_val, use_face_influence);
        }
      }
      break;
    case MOD_WEIGHTEDNORMAL_MODE_ANGLE:
    case MOD_WEIGHTEDNORMAL_MODE_FACE_ANGLE:
      for (int i = 0; i < corner_verts.size(); i++) {
        const int corner = mode_pair[i].index;
        const float ml_val = mode_pair[i].val;
        const int space_index = lnors_spacearr.corner_space_indices[corner];

        const int face_index = loop_to_face[corner];
        const int mv_index = corner_verts[corner];
        WeightedNormalDataAggregateItem *item_data = keep_sharp ? &items_data[space_index] :
                                                                  &items_data[mv_index];

        aggregate_item_normal(
            wnmd, wn_data, item_data, mv_index, face_index, ml_val, use_face_influence);
      }
      break;
    default:
      BLI_assert_unreachable();
  }

  /* Validate computed weighted normals. */
  for (int item_index : items_data.index_range()) {
    if (normalize_v3(items_data[item_index].normal) < CLNORS_VALID_VEC_LEN) {
      zero_v3(items_data[item_index].normal);
    }
  }

  if (keep_sharp) {
    /* Set loop normals for normal computed for each lnor space (smooth fan).
     * Note that corner_normals is already populated with clnors
     * (before this modifier is applied, at start of this function),
     * so no need to recompute them here. */
    for (int corner = 0; corner < corner_verts.size(); corner++) {
      const int space_index = lnors_spacearr.corner_space_indices[corner];
      WeightedNormalDataAggregateItem *item_data = &items_data[space_index];
      if (!is_zero_v3(item_data->normal)) {
        copy_v3_v3(corner_normals[corner], item_data->normal);
      }
    }

    blender::bke::mesh::normals_corner_custom_set(positions,
                                                  edges,
                                                  faces,
                                                  corner_verts,
                                                  corner_edges,
                                                  wn_data->vert_normals,
                                                  face_normals,
                                                  wn_data->sharp_faces,
                                                  wn_data->sharp_edges,
                                                  corner_normals,
                                                  clnors);
  }
  else {
    /* TODO: Ideally, we could add an option to `BKE_mesh_normals_loop_custom_[from_verts_]set()`
     * to keep current clnors instead of resetting them to default auto-computed ones,
     * when given new custom normal is zero-vec.
     * But this is not exactly trivial change, better to keep this optimization for later...
     */
    if (!has_vgroup) {
      /* NOTE: in theory, we could avoid this extra allocation & copying...
       * But think we can live with it for now,
       * and it makes code simpler & cleaner. */
      blender::Array<blender::float3> vert_normals(verts_num, float3(0.0f));

      for (int corner = 0; corner < corner_verts.size(); corner++) {
        const int mv_index = corner_verts[corner];
        copy_v3_v3(vert_normals[mv_index], items_data[mv_index].normal);
      }

      blender::bke::mesh::normals_corner_custom_set_from_verts(positions,
                                                               edges,
                                                               faces,
                                                               corner_verts,
                                                               corner_edges,
                                                               wn_data->vert_normals,
                                                               face_normals,
                                                               wn_data->sharp_faces,
                                                               wn_data->sharp_edges,
                                                               vert_normals,
                                                               clnors);
    }
    else {
      corner_normals.reinitialize(corner_verts.size());
      blender::bke::mesh::normals_calc_corners(positions,
                                               edges,
                                               faces,
                                               corner_verts,
                                               corner_edges,
                                               loop_to_face,
                                               face_normals,
                                               wn_data->sharp_edges,
                                               wn_data->sharp_faces,
                                               clnors,
                                               nullptr,
                                               corner_normals);

      for (int corner = 0; corner < corner_verts.size(); corner++) {
        const int item_index = corner_verts[corner];
        if (!is_zero_v3(items_data[item_index].normal)) {
          copy_v3_v3(corner_normals[corner], items_data[item_index].normal);
        }
      }
      blender::bke::mesh::normals_corner_custom_set(positions,
                                                    edges,
                                                    faces,
                                                    corner_verts,
                                                    corner_edges,
                                                    wn_data->vert_normals,
                                                    face_normals,
                                                    wn_data->sharp_faces,
                                                    wn_data->sharp_edges,
                                                    corner_normals,
                                                    clnors);
    }
  }
}

static void wn_face_area(WeightedNormalModifierData *wnmd, WeightedNormalData *wn_data)
{
  const blender::Span<blender::float3> positions = wn_data->vert_positions;
  const blender::OffsetIndices faces = wn_data->faces;
  const blender::Span<int> corner_verts = wn_data->corner_verts;

  ModePair *face_area = MEM_malloc_arrayN<ModePair>(size_t(faces.size()), __func__);

  ModePair *f_area = face_area;
  for (const int i : faces.index_range()) {
    f_area[i].val = blender::bke::mesh::face_area_calc(positions, corner_verts.slice(faces[i]));
    f_area[i].index = i;
  }

  qsort(face_area, faces.size(), sizeof(*face_area), modepair_cmp_by_val_inverse);

  wn_data->mode_pair = face_area;
  apply_weights_vertex_normal(wnmd, wn_data);
}

static void wn_corner_angle(WeightedNormalModifierData *wnmd, WeightedNormalData *wn_data)
{
  const blender::Span<blender::float3> positions = wn_data->vert_positions;
  const blender::OffsetIndices faces = wn_data->faces;
  const blender::Span<int> corner_verts = wn_data->corner_verts;

  ModePair *corner_angle = MEM_malloc_arrayN<ModePair>(size_t(corner_verts.size()), __func__);

  for (const int i : faces.index_range()) {
    const blender::IndexRange face = faces[i];
    float *index_angle = MEM_malloc_arrayN<float>(size_t(face.size()), __func__);
    blender::bke::mesh::face_angles_calc(
        positions, corner_verts.slice(face), {index_angle, face.size()});

    ModePair *c_angl = &corner_angle[face.start()];
    float *angl = index_angle;
    for (int corner = face.start(); corner < face.start() + face.size();
         corner++, c_angl++, angl++)
    {
      c_angl->val = float(M_PI) - *angl;
      c_angl->index = corner;
    }
    MEM_freeN(index_angle);
  }

  qsort(corner_angle, corner_verts.size(), sizeof(*corner_angle), modepair_cmp_by_val_inverse);

  wn_data->mode_pair = corner_angle;
  apply_weights_vertex_normal(wnmd, wn_data);
}

static void wn_face_with_angle(WeightedNormalModifierData *wnmd, WeightedNormalData *wn_data)
{
  const blender::Span<blender::float3> positions = wn_data->vert_positions;
  const blender::OffsetIndices faces = wn_data->faces;
  const blender::Span<int> corner_verts = wn_data->corner_verts;

  ModePair *combined = MEM_malloc_arrayN<ModePair>(size_t(corner_verts.size()), __func__);

  for (const int i : faces.index_range()) {
    const blender::IndexRange face = faces[i];
    const blender::Span<int> face_verts = corner_verts.slice(face);
    const float face_area = blender::bke::mesh::face_area_calc(positions, face_verts);
    float *index_angle = MEM_malloc_arrayN<float>(size_t(face.size()), __func__);
    blender::bke::mesh::face_angles_calc(positions, face_verts, {index_angle, face.size()});

    ModePair *cmbnd = &combined[face.start()];
    float *angl = index_angle;
    for (int corner = face.start(); corner < face.start() + face.size(); corner++, cmbnd++, angl++)
    {
      /* In this case val is product of corner angle and face area. */
      cmbnd->val = (float(M_PI) - *angl) * face_area;
      cmbnd->index = corner;
    }
    MEM_freeN(index_angle);
  }

  qsort(combined, corner_verts.size(), sizeof(*combined), modepair_cmp_by_val_inverse);

  wn_data->mode_pair = combined;
  apply_weights_vertex_normal(wnmd, wn_data);
}

static Mesh *modify_mesh(ModifierData *md, const ModifierEvalContext *ctx, Mesh *mesh)
{
  using namespace blender;
  WeightedNormalModifierData *wnmd = (WeightedNormalModifierData *)md;

  Mesh *result;
  result = (Mesh *)BKE_id_copy_ex(nullptr, &mesh->id, nullptr, LIB_ID_COPY_LOCALIZE);

  const int verts_num = result->verts_num;
  const blender::Span<blender::float3> positions = mesh->vert_positions();
  const blender::Span<int2> edges = mesh->edges();
  const OffsetIndices faces = result->faces();
  const blender::Span<int> corner_verts = mesh->corner_verts();
  const blender::Span<int> corner_edges = mesh->corner_edges();

  /* Right now:
   * If weight = 50 then all faces are given equal weight.
   * If weight > 50 then more weight given to faces with larger values (face area / corner angle).
   * If weight < 50 then more weight given to faces with lesser values. However current calculation
   * does not converge to min/max.
   */
  float weight = float(wnmd->weight) / 50.0f;
  if (wnmd->weight == 100) {
    weight = float(SHRT_MAX);
  }
  else if (wnmd->weight == 1) {
    weight = 1 / float(SHRT_MAX);
  }
  else if ((weight - 1) * 25 > 1) {
    weight = (weight - 1) * 25;
  }

  const MDeformVert *dvert;
  int defgrp_index;
  MOD_get_vgroup(ctx->object, mesh, wnmd->defgrp_name, &dvert, &defgrp_index);

  const Span<int> loop_to_face_map = result->corner_to_face_map();

  bke::MutableAttributeAccessor attributes = result->attributes_for_write();
  bke::SpanAttributeWriter<bool> sharp_edges = attributes.lookup_or_add_for_write_span<bool>(
      "sharp_edge", bke::AttrDomain::Edge);
  bke::SpanAttributeWriter clnors = attributes.lookup_or_add_for_write_span<short2>(
      "custom_normal", bke::AttrDomain::Corner);
  if (!clnors) {
    return result;
  }

  WeightedNormalData wn_data{};
  wn_data.verts_num = verts_num;

  wn_data.vert_positions = positions;
  wn_data.vert_normals = result->vert_normals();
  wn_data.edges = edges;
  wn_data.sharp_edges = sharp_edges.span;

  wn_data.corner_verts = corner_verts;
  wn_data.corner_edges = corner_edges;
  wn_data.loop_to_face = loop_to_face_map;
  wn_data.clnors = clnors.span;

  wn_data.faces = faces;
  wn_data.face_normals = mesh->face_normals_true();
  wn_data.sharp_faces = *attributes.lookup<bool>("sharp_face", bke::AttrDomain::Face);
  wn_data.face_strength = static_cast<const int *>(CustomData_get_layer_named(
      &result->face_data, CD_PROP_INT32, MOD_WEIGHTEDNORMALS_FACEWEIGHT_CDLAYER_ID));

  wn_data.dvert = dvert;
  wn_data.defgrp_index = defgrp_index;
  wn_data.use_invert_vgroup = (wnmd->flag & MOD_WEIGHTEDNORMAL_INVERT_VGROUP) != 0;

  wn_data.weight = weight;
  wn_data.mode = wnmd->mode;

  switch (wnmd->mode) {
    case MOD_WEIGHTEDNORMAL_MODE_FACE:
      wn_face_area(wnmd, &wn_data);
      break;
    case MOD_WEIGHTEDNORMAL_MODE_ANGLE:
      wn_corner_angle(wnmd, &wn_data);
      break;
    case MOD_WEIGHTEDNORMAL_MODE_FACE_ANGLE:
      wn_face_with_angle(wnmd, &wn_data);
      break;
  }

  MEM_SAFE_FREE(wn_data.mode_pair);

  result->runtime->is_original_bmesh = false;

  sharp_edges.finish();
  clnors.finish();

  return result;
}

static void init_data(ModifierData *md)
{
  WeightedNormalModifierData *wnmd = (WeightedNormalModifierData *)md;

  BLI_assert(MEMCMP_STRUCT_AFTER_IS_ZERO(wnmd, modifier));

  MEMCPY_STRUCT_AFTER(wnmd, DNA_struct_default_get(WeightedNormalModifierData), modifier);
}

static void required_data_mask(ModifierData *md, CustomData_MeshMasks *r_cddata_masks)
{
  WeightedNormalModifierData *wnmd = (WeightedNormalModifierData *)md;

  if (wnmd->defgrp_name[0] != '\0') {
    r_cddata_masks->vmask |= CD_MASK_MDEFORMVERT;
  }

  if (wnmd->flag & MOD_WEIGHTEDNORMAL_FACE_INFLUENCE) {
    r_cddata_masks->pmask |= CD_MASK_PROP_INT32;
  }
}

static void panel_draw(const bContext * /*C*/, Panel *panel)
{
  uiLayout *col;
  uiLayout *layout = panel->layout;

  PointerRNA ob_ptr;
  PointerRNA *ptr = modifier_panel_get_property_pointers(panel, &ob_ptr);

  uiLayoutSetPropSep(layout, true);

  uiItemR(layout, ptr, "mode", UI_ITEM_NONE, std::nullopt, ICON_NONE);

  uiItemR(layout, ptr, "weight", UI_ITEM_NONE, IFACE_("Weight"), ICON_NONE);
  uiItemR(layout, ptr, "thresh", UI_ITEM_NONE, IFACE_("Threshold"), ICON_NONE);

  col = uiLayoutColumn(layout, false);
  uiItemR(col, ptr, "keep_sharp", UI_ITEM_NONE, std::nullopt, ICON_NONE);
  uiItemR(col, ptr, "use_face_influence", UI_ITEM_NONE, std::nullopt, ICON_NONE);

  modifier_vgroup_ui(layout, ptr, &ob_ptr, "vertex_group", "invert_vertex_group", std::nullopt);

  modifier_panel_end(layout, ptr);
}

static void panel_register(ARegionType *region_type)
{
  modifier_panel_register(region_type, eModifierType_WeightedNormal, panel_draw);
}

ModifierTypeInfo modifierType_WeightedNormal = {
    /*idname*/ "WeightedNormal",
    /*name*/ N_("WeightedNormal"),
    /*struct_name*/ "WeightedNormalModifierData",
    /*struct_size*/ sizeof(WeightedNormalModifierData),
    /*srna*/ &RNA_WeightedNormalModifier,
    /*type*/ ModifierTypeType::Constructive,
    /*flags*/ eModifierTypeFlag_AcceptsMesh | eModifierTypeFlag_SupportsMapping |
        eModifierTypeFlag_SupportsEditmode | eModifierTypeFlag_EnableInEditmode,
    /*icon*/ ICON_MOD_NORMALEDIT,

    /*copy_data*/ BKE_modifier_copydata_generic,

    /*deform_verts*/ nullptr,
    /*deform_matrices*/ nullptr,
    /*deform_verts_EM*/ nullptr,
    /*deform_matrices_EM*/ nullptr,
    /*modify_mesh*/ modify_mesh,
    /*modify_geometry_set*/ nullptr,

    /*init_data*/ init_data,
    /*required_data_mask*/ required_data_mask,
    /*free_data*/ nullptr,
    /*is_disabled*/ nullptr,
    /*update_depsgraph*/ nullptr,
    /*depends_on_time*/ nullptr,
    /*depends_on_normals*/ nullptr,
    /*foreach_ID_link*/ nullptr,
    /*foreach_tex_link*/ nullptr,
    /*free_runtime_data*/ nullptr,
    /*panel_register*/ panel_register,
    /*blend_write*/ nullptr,
    /*blend_read*/ nullptr,
    /*foreach_cache*/ nullptr,
};