Files
test/source/blender/geometry/intern/mesh_split_edges.cc

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17 KiB
C++

/* SPDX-FileCopyrightText: 2023 Blender Foundation
*
* SPDX-License-Identifier: GPL-2.0-or-later */
#include "BLI_array_utils.hh"
#include "BLI_index_mask.hh"
#include "BLI_ordered_edge.hh"
#include "BLI_vector_set.hh"
#include "BKE_attribute.hh"
#include "BKE_attribute_math.hh"
#include "BKE_mesh.hh"
#include "BKE_mesh_mapping.hh"
#include "GEO_mesh_split_edges.hh"
namespace blender::geometry {
static void add_new_vertices(Mesh &mesh, const Span<int> new_to_old_verts_map)
{
/* These types aren't supported for interpolation below. */
CustomData_free_layers(&mesh.vert_data, CD_SHAPEKEY, mesh.totvert);
CustomData_free_layers(&mesh.vert_data, CD_CLOTH_ORCO, mesh.totvert);
CustomData_free_layers(&mesh.vert_data, CD_MVERT_SKIN, mesh.totvert);
CustomData_realloc(&mesh.vert_data, mesh.totvert, mesh.totvert + new_to_old_verts_map.size());
mesh.totvert += new_to_old_verts_map.size();
bke::MutableAttributeAccessor attributes = mesh.attributes_for_write();
for (const bke::AttributeIDRef &id : attributes.all_ids()) {
if (attributes.lookup_meta_data(id)->domain != ATTR_DOMAIN_POINT) {
continue;
}
bke::GSpanAttributeWriter attribute = attributes.lookup_for_write_span(id);
if (!attribute) {
continue;
}
bke::attribute_math::gather(attribute.span,
new_to_old_verts_map,
attribute.span.take_back(new_to_old_verts_map.size()));
attribute.finish();
}
if (float3 *orco = static_cast<float3 *>(
CustomData_get_layer_for_write(&mesh.vert_data, CD_ORCO, mesh.totvert)))
{
array_utils::gather(Span(orco, mesh.totvert),
new_to_old_verts_map,
MutableSpan(orco, mesh.totvert).take_back(new_to_old_verts_map.size()));
}
if (int *orig_indices = static_cast<int *>(
CustomData_get_layer_for_write(&mesh.vert_data, CD_ORIGINDEX, mesh.totvert)))
{
array_utils::gather(
Span(orig_indices, mesh.totvert),
new_to_old_verts_map,
MutableSpan(orig_indices, mesh.totvert).take_back(new_to_old_verts_map.size()));
}
}
static void add_new_edges(Mesh &mesh,
const Span<int2> new_edges,
const Span<int> new_to_old_edges_map,
const bke::AnonymousAttributePropagationInfo &propagation_info)
{
bke::MutableAttributeAccessor attributes = mesh.attributes_for_write();
/* Store a copy of the IDs locally since we will remove the existing attributes which
* can also free the names, since the API does not provide pointer stability. */
Vector<std::string> named_ids;
Vector<bke::AnonymousAttributeIDPtr> anonymous_ids;
for (const bke::AttributeIDRef &id : attributes.all_ids()) {
if (attributes.lookup_meta_data(id)->domain != ATTR_DOMAIN_EDGE) {
continue;
}
if (id.is_anonymous() && !propagation_info.propagate(id.anonymous_id())) {
continue;
}
if (!id.is_anonymous()) {
if (id.name() != ".edge_verts") {
named_ids.append(id.name());
}
}
else {
anonymous_ids.append(&id.anonymous_id());
id.anonymous_id().add_user();
}
}
Vector<bke::AttributeIDRef> local_edge_ids;
for (const StringRef name : named_ids) {
local_edge_ids.append(name);
}
for (const bke::AnonymousAttributeIDPtr &id : anonymous_ids) {
local_edge_ids.append(*id);
}
/* Build new arrays for the copied edge attributes. Unlike vertices, new edges aren't all at the
* end of the array, so just copying to the new edges would overwrite old values when they were
* still needed. */
struct NewAttributeData {
const bke::AttributeIDRef &local_id;
const CPPType &type;
void *array;
};
Vector<NewAttributeData> dst_attributes;
for (const bke::AttributeIDRef &local_id : local_edge_ids) {
bke::GAttributeReader attribute = attributes.lookup(local_id);
if (!attribute) {
continue;
}
const CPPType &type = attribute.varray.type();
void *new_data = MEM_malloc_arrayN(new_edges.size(), type.size(), __func__);
bke::attribute_math::gather(
attribute.varray, new_to_old_edges_map, GMutableSpan(type, new_data, new_edges.size()));
/* Free the original attribute as soon as possible to lower peak memory usage. */
attributes.remove(local_id);
dst_attributes.append({local_id, type, new_data});
}
int *new_orig_indices = nullptr;
if (const int *orig_indices = static_cast<const int *>(
CustomData_get_layer(&mesh.edge_data, CD_ORIGINDEX)))
{
new_orig_indices = static_cast<int *>(
MEM_malloc_arrayN(new_edges.size(), sizeof(int), __func__));
array_utils::gather(Span(orig_indices, mesh.totedge),
new_to_old_edges_map,
{new_orig_indices, new_edges.size()});
}
CustomData_free(&mesh.edge_data, mesh.totedge);
mesh.totedge = new_edges.size();
CustomData_add_layer_named(
&mesh.edge_data, CD_PROP_INT32_2D, CD_CONSTRUCT, mesh.totedge, ".edge_verts");
mesh.edges_for_write().copy_from(new_edges);
if (new_orig_indices != nullptr) {
CustomData_add_layer_with_data(
&mesh.edge_data, CD_ORIGINDEX, new_orig_indices, mesh.totedge, nullptr);
}
for (NewAttributeData &new_data : dst_attributes) {
attributes.add(new_data.local_id,
ATTR_DOMAIN_EDGE,
bke::cpp_type_to_custom_data_type(new_data.type),
bke::AttributeInitMoveArray(new_data.array));
}
}
/** Split the vertex into duplicates so that each fan has a different vertex. */
static void split_vertex_per_fan(const int vertex,
const int start_offset,
const int orig_verts_num,
const Span<int> fans,
const Span<int> fan_sizes,
const Span<Vector<int>> edge_to_loop_map,
MutableSpan<int> corner_verts,
MutableSpan<int> new_to_old_verts_map)
{
int fan_start = 0;
/* We don't need to create a new vertex for the last fan. That fan can just be connected to the
* original vertex. */
for (const int i : fan_sizes.index_range().drop_back(1)) {
const int new_vert_i = start_offset + i;
new_to_old_verts_map[new_vert_i - orig_verts_num] = vertex;
for (const int edge_i : fans.slice(fan_start, fan_sizes[i])) {
for (const int loop_i : edge_to_loop_map[edge_i]) {
if (corner_verts[loop_i] == vertex) {
corner_verts[loop_i] = new_vert_i;
}
/* The old vertex is on the loop containing the adjacent edge. Since this function is also
* called on the adjacent edge, we don't replace it here. */
}
}
fan_start += fan_sizes[i];
}
}
/**
* Get the index of the adjacent edge to a loop connected to a vertex. In other words, for the
* given face return the unique edge connected to the given vertex and not on the given loop.
*/
static int adjacent_edge(const Span<int> corner_verts,
const Span<int> corner_edges,
const int loop_i,
const IndexRange face,
const int vertex)
{
const int adjacent_loop_i = (corner_verts[loop_i] == vertex) ?
bke::mesh::face_corner_prev(face, loop_i) :
bke::mesh::face_corner_next(face, loop_i);
return corner_edges[adjacent_loop_i];
}
/**
* Calculate the disjoint fans connected to the vertex, where a fan is a group of edges connected
* through faces. The connected_edges vector is rearranged in such a way that edges in the same
* fan are grouped together. The r_fans_sizes Vector gives the sizes of the different fans, and can
* be used to retrieve the fans from connected_edges.
*/
static void calc_vertex_fans(const int vertex,
const Span<int> corner_verts,
const Span<int> new_corner_edges,
const OffsetIndices<int> faces,
const Span<Vector<int>> edge_to_loop_map,
const Span<int> loop_to_face_map,
MutableSpan<int> connected_edges,
Vector<int> &r_fan_sizes)
{
if (connected_edges.size() <= 1) {
r_fan_sizes.append(connected_edges.size());
return;
}
Vector<int> search_edges;
int total_found_edges_num = 0;
int fan_size = 0;
const int total_edge_num = connected_edges.size();
/* Iteratively go through the connected edges. The front contains already handled edges, while
* the back contains unhandled edges. */
while (true) {
/* This edge has not been visited yet. */
int curr_i = total_found_edges_num;
int curr_edge_i = connected_edges[curr_i];
/* Gather all the edges in this fan. */
while (true) {
fan_size++;
/* Add adjacent edges to search stack. */
for (const int loop_i : edge_to_loop_map[curr_edge_i]) {
const int adjacent_edge_i = adjacent_edge(
corner_verts, new_corner_edges, loop_i, faces[loop_to_face_map[loop_i]], vertex);
/* Find out if this edge was visited already. */
int i = curr_i + 1;
for (; i < total_edge_num; i++) {
if (connected_edges[i] == adjacent_edge_i) {
break;
}
}
if (i == total_edge_num) {
/* Already visited this edge. */
continue;
}
search_edges.append(adjacent_edge_i);
curr_i++;
std::swap(connected_edges[curr_i], connected_edges[i]);
}
if (search_edges.is_empty()) {
break;
}
curr_edge_i = search_edges.pop_last();
}
/* We have now collected all the edges in this fan. */
total_found_edges_num += fan_size;
BLI_assert(total_found_edges_num <= total_edge_num);
r_fan_sizes.append(fan_size);
if (total_found_edges_num == total_edge_num) {
/* We have found all the edges, so this final batch must be the last connected fan. */
break;
}
fan_size = 0;
}
}
/**
* Splits the edge into duplicates, so that each edge is connected to one face.
*/
static void split_edge_per_face(const int edge_i,
const int new_edge_start,
MutableSpan<Vector<int>> edge_to_loop_map,
MutableSpan<int> corner_edges)
{
if (edge_to_loop_map[edge_i].size() <= 1) {
return;
}
int new_edge_index = new_edge_start;
for (const int loop_i : edge_to_loop_map[edge_i].as_span().drop_front(1)) {
edge_to_loop_map[new_edge_index].append({loop_i});
corner_edges[loop_i] = new_edge_index;
new_edge_index++;
}
/* Only the first loop is now connected to this edge. */
edge_to_loop_map[edge_i].resize(1);
}
void split_edges(Mesh &mesh,
const IndexMask &mask,
const bke::AnonymousAttributePropagationInfo &propagation_info)
{
/* Flag vertices that need to be split. */
Array<bool> should_split_vert(mesh.totvert, false);
const Span<int2> edges = mesh.edges();
mask.foreach_index([&](const int edge_i) {
const int2 &edge = edges[edge_i];
should_split_vert[edge[0]] = true;
should_split_vert[edge[1]] = true;
});
/* Precalculate topology info. */
Array<Vector<int>> vert_to_edge_map(mesh.totvert);
for (const int i : edges.index_range()) {
vert_to_edge_map[edges[i][0]].append(i);
vert_to_edge_map[edges[i][1]].append(i);
}
Array<int> orig_edge_to_loop_offsets;
Array<int> orig_edge_to_loop_indices;
const GroupedSpan<int> orig_edge_to_loop_map = bke::mesh::build_edge_to_loop_map(
mesh.corner_edges(), mesh.totedge, orig_edge_to_loop_offsets, orig_edge_to_loop_indices);
Array<int> loop_to_face_map = bke::mesh::build_loop_to_face_map(mesh.faces());
/* Store offsets, so we can split edges in parallel. */
Array<int> edge_offsets(edges.size());
Array<int> num_edge_duplicates(edges.size());
int new_edges_size = edges.size();
mask.foreach_index([&](const int edge) {
edge_offsets[edge] = new_edges_size;
/* We add duplicates of the edge for each face (except the first). */
const int num_connected_loops = orig_edge_to_loop_map[edge].size();
const int num_duplicates = std::max(0, num_connected_loops - 1);
new_edges_size += num_duplicates;
num_edge_duplicates[edge] = num_duplicates;
});
const OffsetIndices faces = mesh.faces();
const Array<int> orig_corner_edges = mesh.corner_edges();
IndexMaskMemory memory;
const bke::LooseEdgeCache &loose_edges_cache = mesh.loose_edges();
const IndexMask loose_edges = IndexMask::from_bits(loose_edges_cache.is_loose_bits, memory);
MutableSpan<int> corner_edges = mesh.corner_edges_for_write();
Vector<Vector<int>> edge_to_loop_map(new_edges_size);
threading::parallel_for(edges.index_range(), 512, [&](const IndexRange range) {
for (const int i : range) {
edge_to_loop_map[i].extend(orig_edge_to_loop_map[i]);
}
});
/* Split corner edge indices and update the edge to corner map. This step does not take into
* account future deduplication of the new edges, but is necessary in order to calculate the
* new fans around each vertex. */
mask.foreach_index([&](const int edge_i) {
split_edge_per_face(edge_i, edge_offsets[edge_i], edge_to_loop_map, corner_edges);
});
/* Update vertex to edge map with new vertices from duplicated edges. */
mask.foreach_index([&](const int edge_i) {
const int2 &edge = edges[edge_i];
for (const int duplicate_i : IndexRange(edge_offsets[edge_i], num_edge_duplicates[edge_i])) {
vert_to_edge_map[edge[0]].append(duplicate_i);
vert_to_edge_map[edge[1]].append(duplicate_i);
}
});
MutableSpan<int> corner_verts = mesh.corner_verts_for_write();
/* Calculate vertex fans by reordering the vertex to edge maps. Fans are the the ordered
* groups of consecutive edges between consecutive faces looping around a vertex. */
Array<Vector<int>> vertex_fan_sizes(mesh.totvert);
threading::parallel_for(IndexRange(mesh.totvert), 512, [&](IndexRange range) {
for (const int vert : range) {
if (!should_split_vert[vert]) {
continue;
}
calc_vertex_fans(vert,
corner_verts,
corner_edges,
faces,
edge_to_loop_map,
loop_to_face_map,
vert_to_edge_map[vert],
vertex_fan_sizes[vert]);
}
});
/* Step 2.5: Calculate offsets for next step. */
Array<int> vert_offsets(mesh.totvert);
int total_verts_num = mesh.totvert;
for (const int vert : IndexRange(mesh.totvert)) {
if (!should_split_vert[vert]) {
continue;
}
vert_offsets[vert] = total_verts_num;
/* We only create a new vertex for each fan different from the first. */
total_verts_num += vertex_fan_sizes[vert].size() - 1;
}
/* Step 3: Split the vertices.
* Build a map from each new vertex to an old vertex to use for transferring attributes later. */
const int new_verts_num = total_verts_num - mesh.totvert;
Array<int> new_to_old_verts_map(new_verts_num);
threading::parallel_for(IndexRange(mesh.totvert), 512, [&](IndexRange range) {
for (const int vert : range) {
if (!should_split_vert[vert]) {
continue;
}
split_vertex_per_fan(vert,
vert_offsets[vert],
mesh.totvert,
vert_to_edge_map[vert],
vertex_fan_sizes[vert],
edge_to_loop_map,
corner_verts,
new_to_old_verts_map);
}
});
VectorSet<OrderedEdge> new_edges;
new_edges.reserve(new_edges_size + loose_edges.size());
for (const int i : faces.index_range()) {
const IndexRange face = faces[i];
for (const int corner : face) {
const int vert_1 = corner_verts[corner];
const int vert_2 = corner_verts[bke::mesh::face_corner_next(face, corner)];
corner_edges[corner] = new_edges.index_of_or_add_as(OrderedEdge(vert_1, vert_2));
}
}
loose_edges.foreach_index([&](const int64_t i) { new_edges.add(OrderedEdge(edges[i])); });
Array<int> new_to_old_edges_map(new_edges.size());
loose_edges.to_indices(new_to_old_edges_map.as_mutable_span().take_back(loose_edges.size()));
for (const int i : faces.index_range()) {
const IndexRange face = faces[i];
for (const int corner : face) {
const int new_edge_i = corner_edges[corner];
const int old_edge_i = orig_corner_edges[corner];
new_to_old_edges_map[new_edge_i] = old_edge_i;
}
}
/* Step 5: Resize the mesh to add the new vertices and rebuild the edges. */
add_new_vertices(mesh, new_to_old_verts_map);
add_new_edges(mesh, new_edges.as_span().cast<int2>(), new_to_old_edges_map, propagation_info);
BKE_mesh_tag_edges_split(&mesh);
}
} // namespace blender::geometry