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feat: read support for vn and vt added for OBJ file format #8857

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feat: read support for vn and vt added for OBJ file format #8857

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80 changes: 58 additions & 22 deletions Stream_support/include/CGAL/IO/OBJ.h
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Original file line number Diff line number Diff line change
Expand Up @@ -24,6 +24,8 @@
#include <boost/range/value_type.hpp>
#include <CGAL/Named_function_parameters.h>

#include <CGAL/Kernel_traits.h>

#include <algorithm>
#include <fstream>
#include <iostream>
Expand All @@ -41,14 +43,20 @@ namespace CGAL {
namespace IO {
namespace internal {

template <typename PointRange, typename PolygonRange, typename VertexNormalOutputIterator, typename VertexTextureOutputIterator>
template <typename PointRange,
typename PolygonRange,
typename VertexNormalOutputIterator,
typename VertexTextureOutputIterator,
typename VertexNormalIndexOutputIterator,
typename VertexTextureIndexOutputIterator>
bool read_OBJ(std::istream& is,
PointRange& points,
PolygonRange& polygons,
VertexNormalOutputIterator,
VertexTextureOutputIterator,
const bool verbose = false)
{
VertexNormalOutputIterator vn_out,
VertexTextureOutputIterator vt_out,
VertexNormalIndexOutputIterator vn_id_out,
VertexTextureIndexOutputIterator vt_id_out,
const bool verbose = false) {
if(!is.good())
{
if(verbose)
Expand All @@ -57,13 +65,20 @@ bool read_OBJ(std::istream& is,
}

typedef typename boost::range_value<PointRange>::type Point;
typedef typename CGAL::Kernel_traits<Point>::Kernel Kernel;
typedef typename Kernel::Point_2 Texture;
typedef typename Kernel::Vector_3 Normal;
typedef typename Kernel::FT FT;

set_ascii_mode(is); // obj is ASCII only

int mini(1), maxi(-1);
std::string s;
Point p;

int normal_count = 0;
int texture_count = 0;

std::string line;
bool tex_found(false), norm_found(false);
while(getline(is, line))
Expand Down Expand Up @@ -107,39 +122,61 @@ bool read_OBJ(std::istream& is,
else if(s == "vt")
{
tex_found = true;
texture_count++;
double u = 0.0, v = 0.0;
iss >> u >> v;
*vt_out++ = Texture{FT(u), FT(v)};
}
else if(s == "vn")
{
norm_found = true;
normal_count++;
double nx = 0.0;
double ny = 0.0;
double nz = 0.0;
iss >> nx >> ny >> nz;
*vn_out++ = Normal{FT(nx), FT(ny), FT(nz)};
}
else if(s == "f")
{
int i;
std::string vertex_token;
polygons.emplace_back();
while(iss >> i)
while(iss >> vertex_token)
{
if(i < 1)
{
std::istringstream token_stream(vertex_token);
std::string v_str, vt_str, vn_str;

std::getline(token_stream, v_str, '/');
std::getline(token_stream, vt_str, '/');
std::getline(token_stream, vn_str, '/');

int i = std::stoi(v_str);

if(i < 1) {
const std::size_t n = polygons.back().size();
::CGAL::internal::resize(polygons.back(), n + 1);
polygons.back()[n] = static_cast<int>(points.size()) + i; // negative indices are relative references
if(i < mini)
mini = i;
}
else
{
} else {
const std::size_t n = polygons.back().size();
::CGAL::internal::resize(polygons.back(), n + 1);
polygons.back()[n] = i - 1;
if(i-1 > maxi)
maxi = i-1;
if(i - 1 > maxi)
maxi = i - 1;
}

// We read vt and vn in the given format and then we move on to next vertex
// Texture index
if(!vt_str.empty()) {
int vti = std::stoi(vt_str);
*vt_id_out++ = (vti < 0) ? static_cast<int>(texture_count) + vti : vti - 1;
}

// the format can be "f v1/vt1/vn1 v2/vt2/vn2 v3/vt3/vn3 ..." and we only read vertex ids for now,
// so skip to the next vertex, but be tolerant about which whitespace is used
if (!std::isspace(iss.peek())) {
std::string ignoreme;
iss >> ignoreme;
// Normal index
if(!vn_str.empty()) {
int vni = std::stoi(vn_str);
*vn_id_out++ = (vni < 0) ? static_cast<int>(normal_count) + vni : vni - 1;
}
}

Expand Down Expand Up @@ -244,9 +281,8 @@ bool read_OBJ(std::istream& is,
{
const bool verbose = parameters::choose_parameter(parameters::get_parameter(np, internal_np::verbose), false);

return internal::read_OBJ(is, points, polygons,
CGAL::Emptyset_iterator(), CGAL::Emptyset_iterator(),
verbose);
return internal::read_OBJ(is, points, polygons, CGAL::Emptyset_iterator(), CGAL::Emptyset_iterator(),
CGAL::Emptyset_iterator(), CGAL::Emptyset_iterator(), verbose);
}

/// \ingroup PkgStreamSupportIoFuncsOBJ
Expand Down
20 changes: 20 additions & 0 deletions Stream_support/test/Stream_support/test_OBJ.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -10,13 +10,19 @@
typedef CGAL::Simple_cartesian<double> Kernel;
typedef Kernel::Point_3 Point;
typedef std::vector<std::size_t> Face;
typedef Kernel::Point_2 Texture;
typedef Kernel::Vector_3 Normal;

int main(int argc, char** argv)
{
const char* obj_file = (argc > 1) ? argv[1] : "data/90089.obj";

std::vector<Point> points;
std::vector<Face> polygons;
std::vector<Normal> normals;
std::vector<Texture> UVcoords;
std::vector<int> normal_indices;
std::vector<int> texture_indices;

bool ok = CGAL::IO::read_OBJ(obj_file, points, polygons, CGAL::parameters::verbose(true));
assert(ok);
Expand All @@ -25,6 +31,20 @@ int main(int argc, char** argv)
if(argc == 1)
assert(points.size() == 434 && polygons.size() == 864);

points.clear();
polygons.clear();

// Check for internal read_OBJ with normal and texture coordinates reading capapbility
std::ifstream input(obj_file);
ok = CGAL::IO::internal::read_OBJ(input, points, polygons, std::back_inserter(normals), std::back_inserter(UVcoords),
std::back_inserter(normal_indices), std::back_inserter(texture_indices), true);
assert(ok);
std::cout << points.size() << " points " << polygons.size() << " polygons " << normals.size() << " normals "
<< UVcoords.size() << " texture coords" << std::endl;

if(argc == 1)
assert(points.size() == 434 && polygons.size() == 864 && normals.size() == 242 && UVcoords.size() == 627);

points.clear();
polygons.clear();
std::string obj_string(obj_file);
Expand Down