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// Copyright 2016 The Draco Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
#include "draco/mesh/mesh_attribute_corner_table.h"
#include "draco/mesh/corner_table_iterators.h"
#include "draco/mesh/mesh_misc_functions.h"
namespace draco {
MeshAttributeCornerTable::MeshAttributeCornerTable()
: no_interior_seams_(true), corner_table_(nullptr), valence_cache_(*this) {}
bool MeshAttributeCornerTable::InitEmpty(const CornerTable *table) {
if (table == nullptr) {
return false;
}
valence_cache_.ClearValenceCache();
valence_cache_.ClearValenceCacheInaccurate();
is_edge_on_seam_.assign(table->num_corners(), false);
is_vertex_on_seam_.assign(table->num_vertices(), false);
corner_to_vertex_map_.assign(table->num_corners(), kInvalidVertexIndex);
vertex_to_attribute_entry_id_map_.reserve(table->num_vertices());
vertex_to_left_most_corner_map_.reserve(table->num_vertices());
corner_table_ = table;
no_interior_seams_ = true;
return true;
}
bool MeshAttributeCornerTable::InitFromAttribute(const Mesh *mesh,
const CornerTable *table,
const PointAttribute *att) {
if (!InitEmpty(table)) {
return false;
}
valence_cache_.ClearValenceCache();
valence_cache_.ClearValenceCacheInaccurate();
// Find all necessary data for encoding attributes. For now we check which of
// the mesh vertices is part of an attribute seam, because seams require
// special handling.
for (CornerIndex c(0); c < corner_table_->num_corners(); ++c) {
const FaceIndex f = corner_table_->Face(c);
if (corner_table_->IsDegenerated(f)) {
continue; // Ignore corners on degenerated faces.
}
const CornerIndex opp_corner = corner_table_->Opposite(c);
if (opp_corner == kInvalidCornerIndex) {
// Boundary. Mark it as seam edge.
is_edge_on_seam_[c.value()] = true;
// Mark seam vertices.
VertexIndex v;
v = corner_table_->Vertex(corner_table_->Next(c));
is_vertex_on_seam_[v.value()] = true;
v = corner_table_->Vertex(corner_table_->Previous(c));
is_vertex_on_seam_[v.value()] = true;
continue;
}
if (opp_corner < c) {
continue; // Opposite corner was already processed.
}
CornerIndex act_c(c), act_sibling_c(opp_corner);
for (int i = 0; i < 2; ++i) {
// Get the sibling corners. I.e., the two corners attached to the same
// vertex but divided by the seam edge.
act_c = corner_table_->Next(act_c);
act_sibling_c = corner_table_->Previous(act_sibling_c);
const PointIndex point_id = mesh->CornerToPointId(act_c.value());
const PointIndex sibling_point_id =
mesh->CornerToPointId(act_sibling_c.value());
if (att->mapped_index(point_id) != att->mapped_index(sibling_point_id)) {
no_interior_seams_ = false;
is_edge_on_seam_[c.value()] = true;
is_edge_on_seam_[opp_corner.value()] = true;
// Mark seam vertices.
is_vertex_on_seam_[corner_table_
->Vertex(corner_table_->Next(CornerIndex(c)))
.value()] = true;
is_vertex_on_seam_[corner_table_
->Vertex(corner_table_->Previous(CornerIndex(c)))
.value()] = true;
is_vertex_on_seam_
[corner_table_->Vertex(corner_table_->Next(opp_corner)).value()] =
true;
is_vertex_on_seam_[corner_table_
->Vertex(corner_table_->Previous(opp_corner))
.value()] = true;
break;
}
}
}
RecomputeVertices(mesh, att);
return true;
}
void MeshAttributeCornerTable::AddSeamEdge(CornerIndex c) {
DRACO_DCHECK(GetValenceCache().IsCacheEmpty());
is_edge_on_seam_[c.value()] = true;
// Mark seam vertices.
is_vertex_on_seam_[corner_table_->Vertex(corner_table_->Next(c)).value()] =
true;
is_vertex_on_seam_[corner_table_->Vertex(corner_table_->Previous(c))
.value()] = true;
const CornerIndex opp_corner = corner_table_->Opposite(c);
if (opp_corner != kInvalidCornerIndex) {
no_interior_seams_ = false;
is_edge_on_seam_[opp_corner.value()] = true;
is_vertex_on_seam_[corner_table_->Vertex(corner_table_->Next(opp_corner))
.value()] = true;
is_vertex_on_seam_
[corner_table_->Vertex(corner_table_->Previous(opp_corner)).value()] =
true;
}
}
void MeshAttributeCornerTable::RecomputeVertices(const Mesh *mesh,
const PointAttribute *att) {
DRACO_DCHECK(GetValenceCache().IsCacheEmpty());
if (mesh != nullptr && att != nullptr) {
RecomputeVerticesInternal<true>(mesh, att);
} else {
RecomputeVerticesInternal<false>(nullptr, nullptr);
}
}
template <bool init_vertex_to_attribute_entry_map>
void MeshAttributeCornerTable::RecomputeVerticesInternal(
const Mesh *mesh, const PointAttribute *att) {
DRACO_DCHECK(GetValenceCache().IsCacheEmpty());
vertex_to_attribute_entry_id_map_.clear();
vertex_to_left_most_corner_map_.clear();
int num_new_vertices = 0;
for (VertexIndex v(0); v < corner_table_->num_vertices(); ++v) {
const CornerIndex c = corner_table_->LeftMostCorner(v);
if (c == kInvalidCornerIndex) {
continue; // Isolated vertex?
}
AttributeValueIndex first_vert_id(num_new_vertices++);
if (init_vertex_to_attribute_entry_map) {
const PointIndex point_id = mesh->CornerToPointId(c.value());
vertex_to_attribute_entry_id_map_.push_back(att->mapped_index(point_id));
} else {
// Identity mapping
vertex_to_attribute_entry_id_map_.push_back(first_vert_id);
}
CornerIndex first_c = c;
CornerIndex act_c;
// Check if the vertex is on a seam edge, if it is we need to find the first
// attribute entry on the seam edge when traversing in the CCW direction.
if (is_vertex_on_seam_[v.value()]) {
// Try to swing left on the modified corner table. We need to get the
// first corner that defines an attribute seam.
act_c = SwingLeft(first_c);
while (act_c != kInvalidCornerIndex) {
first_c = act_c;
act_c = SwingLeft(act_c);
}
}
corner_to_vertex_map_[first_c.value()] = VertexIndex(first_vert_id.value());
vertex_to_left_most_corner_map_.push_back(first_c);
act_c = corner_table_->SwingRight(first_c);
while (act_c != kInvalidCornerIndex && act_c != first_c) {
if (IsCornerOppositeToSeamEdge(corner_table_->Next(act_c))) {
first_vert_id = AttributeValueIndex(num_new_vertices++);
if (init_vertex_to_attribute_entry_map) {
const PointIndex point_id = mesh->CornerToPointId(act_c.value());
vertex_to_attribute_entry_id_map_.push_back(
att->mapped_index(point_id));
} else {
// Identity mapping.
vertex_to_attribute_entry_id_map_.push_back(first_vert_id);
}
vertex_to_left_most_corner_map_.push_back(act_c);
}
corner_to_vertex_map_[act_c.value()] = VertexIndex(first_vert_id.value());
act_c = corner_table_->SwingRight(act_c);
}
}
}
int MeshAttributeCornerTable::Valence(VertexIndex v) const {
if (v == kInvalidVertexIndex) {
return -1;
}
return ConfidentValence(v);
}
int MeshAttributeCornerTable::ConfidentValence(VertexIndex v) const {
DRACO_DCHECK_LT(v.value(), num_vertices());
draco::VertexRingIterator<MeshAttributeCornerTable> vi(this, v);
int valence = 0;
for (; !vi.End(); vi.Next()) {
++valence;
}
return valence;
}
} // namespace draco
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