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Diffstat (limited to 'source/blender/io/wavefront_obj/exporter/obj_export_file_writer.cc')
| -rw-r--r-- | source/blender/io/wavefront_obj/exporter/obj_export_file_writer.cc | 626 |
1 files changed, 626 insertions, 0 deletions
diff --git a/source/blender/io/wavefront_obj/exporter/obj_export_file_writer.cc b/source/blender/io/wavefront_obj/exporter/obj_export_file_writer.cc new file mode 100644 index 00000000000..d92d1c5ad48 --- /dev/null +++ b/source/blender/io/wavefront_obj/exporter/obj_export_file_writer.cc @@ -0,0 +1,626 @@ +/* + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version 2 + * of the License, or (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software Foundation, + * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. + */ + +/** \file + * \ingroup obj + */ + +#include <algorithm> +#include <cstdio> + +#include "BKE_blender_version.h" + +#include "BLI_path_util.h" + +#include "obj_export_mesh.hh" +#include "obj_export_mtl.hh" +#include "obj_export_nurbs.hh" + +#include "obj_export_file_writer.hh" + +namespace blender::io::obj { +/** + * Per reference http://www.martinreddy.net/gfx/3d/OBJ.spec: + * To turn off smoothing groups, use a value of 0 or off. + * Polygonal elements use group numbers to put elements in different smoothing groups. + * For free-form surfaces, smoothing groups are either turned on or off; + * there is no difference between values greater than 0. + */ +const int SMOOTH_GROUP_DISABLED = 0; +const int SMOOTH_GROUP_DEFAULT = 1; + +const char *DEFORM_GROUP_DISABLED = "off"; +/* There is no deform group default name. Use what the user set in the UI. */ + +/** + * Per reference http://www.martinreddy.net/gfx/3d/OBJ.spec: + * Once a material is assigned, it cannot be turned off; it can only be changed. + * If a material name is not specified, a white material is used. + * So an empty material name is written. */ +const char *MATERIAL_GROUP_DISABLED = ""; + +/** + * Write one line of polygon indices as "f v1/vt1/vn1 v2/vt2/vn2 ...". + */ +void OBJWriter::write_vert_uv_normal_indices(Span<int> vert_indices, + Span<int> uv_indices, + Span<int> normal_indices) const +{ + BLI_assert(vert_indices.size() == uv_indices.size() && + vert_indices.size() == normal_indices.size()); + file_handler_->write<eOBJSyntaxElement::poly_element_begin>(); + for (int j = 0; j < vert_indices.size(); j++) { + file_handler_->write<eOBJSyntaxElement::vertex_uv_normal_indices>( + vert_indices[j] + index_offsets_.vertex_offset + 1, + uv_indices[j] + index_offsets_.uv_vertex_offset + 1, + normal_indices[j] + index_offsets_.normal_offset + 1); + } + file_handler_->write<eOBJSyntaxElement::poly_element_end>(); +} + +/** + * Write one line of polygon indices as "f v1//vn1 v2//vn2 ...". + */ +void OBJWriter::write_vert_normal_indices(Span<int> vert_indices, + Span<int> /*uv_indices*/, + Span<int> normal_indices) const +{ + BLI_assert(vert_indices.size() == normal_indices.size()); + file_handler_->write<eOBJSyntaxElement::poly_element_begin>(); + for (int j = 0; j < vert_indices.size(); j++) { + file_handler_->write<eOBJSyntaxElement::vertex_normal_indices>( + vert_indices[j] + index_offsets_.vertex_offset + 1, + normal_indices[j] + index_offsets_.normal_offset + 1); + } + file_handler_->write<eOBJSyntaxElement::poly_element_end>(); +} + +/** + * Write one line of polygon indices as "f v1/vt1 v2/vt2 ...". + */ +void OBJWriter::write_vert_uv_indices(Span<int> vert_indices, + Span<int> uv_indices, + Span<int> /*normal_indices*/) const +{ + BLI_assert(vert_indices.size() == uv_indices.size()); + file_handler_->write<eOBJSyntaxElement::poly_element_begin>(); + for (int j = 0; j < vert_indices.size(); j++) { + file_handler_->write<eOBJSyntaxElement::vertex_uv_indices>( + vert_indices[j] + index_offsets_.vertex_offset + 1, + uv_indices[j] + index_offsets_.uv_vertex_offset + 1); + } + file_handler_->write<eOBJSyntaxElement::poly_element_end>(); +} + +/** + * Write one line of polygon indices as "f v1 v2 ...". + */ +void OBJWriter::write_vert_indices(Span<int> vert_indices, + Span<int> /*uv_indices*/, + Span<int> /*normal_indices*/) const +{ + file_handler_->write<eOBJSyntaxElement::poly_element_begin>(); + for (const int vert_index : vert_indices) { + file_handler_->write<eOBJSyntaxElement::vertex_indices>(vert_index + + index_offsets_.vertex_offset + 1); + } + file_handler_->write<eOBJSyntaxElement::poly_element_end>(); +} + +void OBJWriter::write_header() const +{ + using namespace std::string_literals; + file_handler_->write<eOBJSyntaxElement::string>("# Blender "s + BKE_blender_version_string() + + "\n"); + file_handler_->write<eOBJSyntaxElement::string>("# www.blender.org\n"); +} + +/** + * Write file name of Material Library in .OBJ file. + */ +void OBJWriter::write_mtllib_name(const StringRefNull mtl_filepath) const +{ + /* Split .MTL file path into parent directory and filename. */ + char mtl_file_name[FILE_MAXFILE]; + char mtl_dir_name[FILE_MAXDIR]; + BLI_split_dirfile(mtl_filepath.data(), mtl_dir_name, mtl_file_name, FILE_MAXDIR, FILE_MAXFILE); + file_handler_->write<eOBJSyntaxElement::mtllib>(mtl_file_name); +} + +/** + * Write an object's group with mesh and/or material name appended conditionally. + */ +void OBJWriter::write_object_group(const OBJMesh &obj_mesh_data) const +{ + /* "o object_name" is not mandatory. A valid .OBJ file may contain neither + * "o name" nor "g group_name". */ + BLI_assert(export_params_.export_object_groups); + if (!export_params_.export_object_groups) { + return; + } + const std::string object_name = obj_mesh_data.get_object_name(); + const char *object_mesh_name = obj_mesh_data.get_object_mesh_name(); + const char *object_material_name = obj_mesh_data.get_object_material_name(0); + if (export_params_.export_materials && export_params_.export_material_groups && + object_material_name) { + file_handler_->write<eOBJSyntaxElement::object_group>(object_name + "_" + object_mesh_name + + "_" + object_material_name); + return; + } + file_handler_->write<eOBJSyntaxElement::object_group>(object_name + "_" + object_mesh_name); +} + +/** + * Write object's name or group. + */ +void OBJWriter::write_object_name(const OBJMesh &obj_mesh_data) const +{ + const char *object_name = obj_mesh_data.get_object_name(); + if (export_params_.export_object_groups) { + write_object_group(obj_mesh_data); + return; + } + file_handler_->write<eOBJSyntaxElement::object_name>(object_name); +} + +/** + * Write vertex coordinates for all vertices as "v x y z". + */ +void OBJWriter::write_vertex_coords(const OBJMesh &obj_mesh_data) const +{ + const int tot_vertices = obj_mesh_data.tot_vertices(); + for (int i = 0; i < tot_vertices; i++) { + float3 vertex = obj_mesh_data.calc_vertex_coords(i, export_params_.scaling_factor); + file_handler_->write<eOBJSyntaxElement::vertex_coords>(vertex[0], vertex[1], vertex[2]); + } +} + +/** + * Write UV vertex coordinates for all vertices as "vt u v". + * \note UV indices are stored here, but written later. + */ +void OBJWriter::write_uv_coords(OBJMesh &r_obj_mesh_data) const +{ + Vector<std::array<float, 2>> uv_coords; + /* UV indices are calculated and stored in an OBJMesh member here. */ + r_obj_mesh_data.store_uv_coords_and_indices(uv_coords); + + for (const std::array<float, 2> &uv_vertex : uv_coords) { + file_handler_->write<eOBJSyntaxElement::uv_vertex_coords>(uv_vertex[0], uv_vertex[1]); + } +} + +/** + * Write loop normals for smooth-shaded polygons, and polygon normals otherwise, as "vn x y z". + */ +void OBJWriter::write_poly_normals(const OBJMesh &obj_mesh_data) const +{ + obj_mesh_data.ensure_mesh_normals(); + Vector<float3> lnormals; + const int tot_polygons = obj_mesh_data.tot_polygons(); + for (int i = 0; i < tot_polygons; i++) { + if (obj_mesh_data.is_ith_poly_smooth(i)) { + obj_mesh_data.calc_loop_normals(i, lnormals); + for (const float3 &lnormal : lnormals) { + file_handler_->write<eOBJSyntaxElement::normal>(lnormal[0], lnormal[1], lnormal[2]); + } + } + else { + float3 poly_normal = obj_mesh_data.calc_poly_normal(i); + file_handler_->write<eOBJSyntaxElement::normal>( + poly_normal[0], poly_normal[1], poly_normal[2]); + } + } +} + +/** + * Write smooth group if polygon at the given index is shaded smooth else "s 0" + */ +int OBJWriter::write_smooth_group(const OBJMesh &obj_mesh_data, + const int poly_index, + const int last_poly_smooth_group) const +{ + int current_group = SMOOTH_GROUP_DISABLED; + if (!export_params_.export_smooth_groups && obj_mesh_data.is_ith_poly_smooth(poly_index)) { + /* Smooth group calculation is disabled, but polygon is smooth-shaded. */ + current_group = SMOOTH_GROUP_DEFAULT; + } + else if (obj_mesh_data.is_ith_poly_smooth(poly_index)) { + /* Smooth group calc is enabled and polygon is smooth–shaded, so find the group. */ + current_group = obj_mesh_data.ith_smooth_group(poly_index); + } + + if (current_group == last_poly_smooth_group) { + /* Group has already been written, even if it is "s 0". */ + return current_group; + } + file_handler_->write<eOBJSyntaxElement::smooth_group>(current_group); + return current_group; +} + +/** + * Write material name and material group of a polygon in the .OBJ file. + * \return #mat_nr of the polygon at the given index. + * \note It doesn't write to the material library. + */ +int16_t OBJWriter::write_poly_material(const OBJMesh &obj_mesh_data, + const int poly_index, + const int16_t last_poly_mat_nr, + std::function<const char *(int)> matname_fn) const +{ + if (!export_params_.export_materials || obj_mesh_data.tot_materials() <= 0) { + return last_poly_mat_nr; + } + const int16_t current_mat_nr = obj_mesh_data.ith_poly_matnr(poly_index); + /* Whenever a polygon with a new material is encountered, write its material + * and/or group, otherwise pass. */ + if (last_poly_mat_nr == current_mat_nr) { + return current_mat_nr; + } + if (current_mat_nr == NOT_FOUND) { + file_handler_->write<eOBJSyntaxElement::poly_usemtl>(MATERIAL_GROUP_DISABLED); + return current_mat_nr; + } + if (export_params_.export_object_groups) { + write_object_group(obj_mesh_data); + } + const char *mat_name = matname_fn(current_mat_nr); + if (!mat_name) { + mat_name = MATERIAL_GROUP_DISABLED; + } + file_handler_->write<eOBJSyntaxElement::poly_usemtl>(mat_name); + + return current_mat_nr; +} + +/** + * Write the name of the deform group of a polygon. + */ +int16_t OBJWriter::write_vertex_group(const OBJMesh &obj_mesh_data, + const int poly_index, + const int16_t last_poly_vertex_group) const +{ + if (!export_params_.export_vertex_groups) { + return last_poly_vertex_group; + } + const int16_t current_group = obj_mesh_data.get_poly_deform_group_index(poly_index); + + if (current_group == last_poly_vertex_group) { + /* No vertex group found in this polygon, just like in the last iteration. */ + return current_group; + } + if (current_group == NOT_FOUND) { + file_handler_->write<eOBJSyntaxElement::object_group>(DEFORM_GROUP_DISABLED); + return current_group; + } + file_handler_->write<eOBJSyntaxElement::object_group>( + obj_mesh_data.get_poly_deform_group_name(current_group)); + return current_group; +} + +/** + * \return Writer function with appropriate polygon-element syntax. + */ +OBJWriter::func_vert_uv_normal_indices OBJWriter::get_poly_element_writer( + const int total_uv_vertices) const +{ + if (export_params_.export_normals) { + if (export_params_.export_uv && (total_uv_vertices > 0)) { + /* Write both normals and UV indices. */ + return &OBJWriter::write_vert_uv_normal_indices; + } + /* Write normals indices. */ + return &OBJWriter::write_vert_normal_indices; + } + /* Write UV indices. */ + if (export_params_.export_uv && (total_uv_vertices > 0)) { + return &OBJWriter::write_vert_uv_indices; + } + /* Write neither normals nor UV indices. */ + return &OBJWriter::write_vert_indices; +} + +/** + * Write polygon elements with at least vertex indices, and conditionally with UV vertex + * indices and polygon normal indices. Also write groups: smooth, vertex, material. + * The matname_fn turns a 0-indexed material slot number in an Object into the + * name used in the .obj file. + * \note UV indices were stored while writing UV vertices. + */ +void OBJWriter::write_poly_elements(const OBJMesh &obj_mesh_data, + std::function<const char *(int)> matname_fn) +{ + int last_poly_smooth_group = NEGATIVE_INIT; + int16_t last_poly_vertex_group = NEGATIVE_INIT; + int16_t last_poly_mat_nr = NEGATIVE_INIT; + + const func_vert_uv_normal_indices poly_element_writer = get_poly_element_writer( + obj_mesh_data.tot_uv_vertices()); + + /* Number of normals may not be equal to number of polygons due to smooth shading. */ + int per_object_tot_normals = 0; + const int tot_polygons = obj_mesh_data.tot_polygons(); + for (int i = 0; i < tot_polygons; i++) { + Vector<int> poly_vertex_indices = obj_mesh_data.calc_poly_vertex_indices(i); + Span<int> poly_uv_indices = obj_mesh_data.calc_poly_uv_indices(i); + /* For an Object, a normal index depends on how many of its normals have been written before + * it. This is unknown because of smooth shading. So pass "per object total normals" + * and update it after each call. */ + int new_normals = 0; + Vector<int> poly_normal_indices; + std::tie(new_normals, poly_normal_indices) = obj_mesh_data.calc_poly_normal_indices( + i, per_object_tot_normals); + per_object_tot_normals += new_normals; + + last_poly_smooth_group = write_smooth_group(obj_mesh_data, i, last_poly_smooth_group); + last_poly_vertex_group = write_vertex_group(obj_mesh_data, i, last_poly_vertex_group); + last_poly_mat_nr = write_poly_material(obj_mesh_data, i, last_poly_mat_nr, matname_fn); + (this->*poly_element_writer)(poly_vertex_indices, poly_uv_indices, poly_normal_indices); + } + /* Unusual: Other indices are updated in #OBJWriter::update_index_offsets. */ + index_offsets_.normal_offset += per_object_tot_normals; +} + +/** + * Write loose edges of a mesh as "l v1 v2". + */ +void OBJWriter::write_edges_indices(const OBJMesh &obj_mesh_data) const +{ + obj_mesh_data.ensure_mesh_edges(); + const int tot_edges = obj_mesh_data.tot_edges(); + for (int edge_index = 0; edge_index < tot_edges; edge_index++) { + const std::optional<std::array<int, 2>> vertex_indices = + obj_mesh_data.calc_loose_edge_vert_indices(edge_index); + if (!vertex_indices) { + continue; + } + file_handler_->write<eOBJSyntaxElement::edge>( + (*vertex_indices)[0] + index_offsets_.vertex_offset + 1, + (*vertex_indices)[1] + index_offsets_.vertex_offset + 1); + } +} + +/** + * Write a NURBS curve to the .OBJ file in parameter form. + */ +void OBJWriter::write_nurbs_curve(const OBJCurve &obj_nurbs_data) const +{ + const int total_splines = obj_nurbs_data.total_splines(); + for (int spline_idx = 0; spline_idx < total_splines; spline_idx++) { + const int total_vertices = obj_nurbs_data.total_spline_vertices(spline_idx); + for (int vertex_idx = 0; vertex_idx < total_vertices; vertex_idx++) { + const float3 vertex_coords = obj_nurbs_data.vertex_coordinates( + spline_idx, vertex_idx, export_params_.scaling_factor); + file_handler_->write<eOBJSyntaxElement::vertex_coords>( + vertex_coords[0], vertex_coords[1], vertex_coords[2]); + } + + const char *nurbs_name = obj_nurbs_data.get_curve_name(); + const int nurbs_degree = obj_nurbs_data.get_nurbs_degree(spline_idx); + file_handler_->write<eOBJSyntaxElement::object_group>(nurbs_name); + file_handler_->write<eOBJSyntaxElement::cstype>(); + file_handler_->write<eOBJSyntaxElement::nurbs_degree>(nurbs_degree); + /** + * The numbers written here are indices into the vertex coordinates written + * earlier, relative to the line that is going to be written. + * [0.0 - 1.0] is the curve parameter range. + * 0.0 1.0 -1 -2 -3 -4 for a non-cyclic curve with 4 vertices. + * 0.0 1.0 -1 -2 -3 -4 -1 -2 -3 for a cyclic curve with 4 vertices. + */ + const int total_control_points = obj_nurbs_data.total_spline_control_points(spline_idx); + file_handler_->write<eOBJSyntaxElement::curve_element_begin>(); + for (int i = 0; i < total_control_points; i++) { + /* "+1" to keep indices one-based, even if they're negative: i.e., -1 refers to the + * last vertex coordinate, -2 second last. */ + file_handler_->write<eOBJSyntaxElement::vertex_indices>(-((i % total_vertices) + 1)); + } + file_handler_->write<eOBJSyntaxElement::curve_element_end>(); + + /** + * In "parm u 0 0.1 .." line:, (total control points + 2) equidistant numbers in the + * parameter range are inserted. + */ + file_handler_->write<eOBJSyntaxElement::nurbs_parameter_begin>(); + for (int i = 1; i <= total_control_points + 2; i++) { + file_handler_->write<eOBJSyntaxElement::nurbs_parameters>(1.0f * i / + (total_control_points + 2 + 1)); + } + file_handler_->write<eOBJSyntaxElement::nurbs_parameter_end>(); + + file_handler_->write<eOBJSyntaxElement::nurbs_group_end>(); + } +} + +/** + * When there are multiple objects in a frame, the indices of previous objects' coordinates or + * normals add up. + */ +void OBJWriter::update_index_offsets(const OBJMesh &obj_mesh_data) +{ + index_offsets_.vertex_offset += obj_mesh_data.tot_vertices(); + index_offsets_.uv_vertex_offset += obj_mesh_data.tot_uv_vertices(); + /* Normal index is updated right after writing the normals. */ +} + +/* -------------------------------------------------------------------- */ +/** \name .MTL writers. + * \{ */ + +/** + * Convert #float3 to string of space-separated numbers, with no leading or trailing space. + * Only to be used in NON-performance-critical code. + */ +static std::string float3_to_string(const float3 &numbers) +{ + std::ostringstream r_string; + r_string << numbers[0] << " " << numbers[1] << " " << numbers[2]; + return r_string.str(); +}; + +/* + * Create the .MTL file. + */ +MTLWriter::MTLWriter(const char *obj_filepath) noexcept(false) +{ + mtl_filepath_ = obj_filepath; + const bool ok = BLI_path_extension_replace(mtl_filepath_.data(), FILE_MAX, ".mtl"); + if (!ok) { + throw std::system_error(ENAMETOOLONG, std::system_category(), ""); + } + file_handler_ = std::make_unique<FileHandler<eFileType::MTL>>(mtl_filepath_); +} + +void MTLWriter::write_header(const char *blen_filepath) const +{ + using namespace std::string_literals; + const char *blen_basename = (blen_filepath && blen_filepath[0] != '\0') ? + BLI_path_basename(blen_filepath) : + "None"; + file_handler_->write<eMTLSyntaxElement::string>("# Blender "s + BKE_blender_version_string() + + " MTL File: '" + blen_basename + "'\n"); + file_handler_->write<eMTLSyntaxElement::string>("# www.blender.org\n"); +} + +StringRefNull MTLWriter::mtl_file_path() const +{ + return mtl_filepath_; +} + +/** + * Write properties sourced from p-BSDF node or #Object.Material. + */ +void MTLWriter::write_bsdf_properties(const MTLMaterial &mtl_material) +{ + file_handler_->write<eMTLSyntaxElement::Ns>(mtl_material.Ns); + file_handler_->write<eMTLSyntaxElement::Ka>( + mtl_material.Ka.x, mtl_material.Ka.y, mtl_material.Ka.z); + file_handler_->write<eMTLSyntaxElement::Kd>( + mtl_material.Kd.x, mtl_material.Kd.y, mtl_material.Kd.z); + file_handler_->write<eMTLSyntaxElement::Ks>( + mtl_material.Ks.x, mtl_material.Ks.y, mtl_material.Ks.z); + file_handler_->write<eMTLSyntaxElement::Ke>( + mtl_material.Ke.x, mtl_material.Ke.y, mtl_material.Ke.z); + file_handler_->write<eMTLSyntaxElement::Ni>(mtl_material.Ni); + file_handler_->write<eMTLSyntaxElement::d>(mtl_material.d); + file_handler_->write<eMTLSyntaxElement::illum>(mtl_material.illum); +} + +/** + * Write a texture map in the form "map_XX -s 1. 1. 1. -o 0. 0. 0. [-bm 1.] path/to/image". + */ +void MTLWriter::write_texture_map( + const MTLMaterial &mtl_material, + const Map<const eMTLSyntaxElement, tex_map_XX>::Item &texture_map) +{ + std::string translation; + std::string scale; + std::string map_bump_strength; + /* Optional strings should have their own leading spaces. */ + if (texture_map.value.translation != float3{0.0f, 0.0f, 0.0f}) { + translation.append(" -s ").append(float3_to_string(texture_map.value.translation)); + } + if (texture_map.value.scale != float3{1.0f, 1.0f, 1.0f}) { + scale.append(" -o ").append(float3_to_string(texture_map.value.scale)); + } + if (texture_map.key == eMTLSyntaxElement::map_Bump && mtl_material.map_Bump_strength > 0.0001f) { + map_bump_strength.append(" -bm ").append(std::to_string(mtl_material.map_Bump_strength)); + } + +#define SYNTAX_DISPATCH(eMTLSyntaxElement) \ + if (texture_map.key == eMTLSyntaxElement) { \ + file_handler_->write<eMTLSyntaxElement>(translation + scale + map_bump_strength, \ + texture_map.value.image_path); \ + return; \ + } + + SYNTAX_DISPATCH(eMTLSyntaxElement::map_Kd); + SYNTAX_DISPATCH(eMTLSyntaxElement::map_Ks); + SYNTAX_DISPATCH(eMTLSyntaxElement::map_Ns); + SYNTAX_DISPATCH(eMTLSyntaxElement::map_d); + SYNTAX_DISPATCH(eMTLSyntaxElement::map_refl); + SYNTAX_DISPATCH(eMTLSyntaxElement::map_Ke); + SYNTAX_DISPATCH(eMTLSyntaxElement::map_Bump); + + BLI_assert(!"This map type was not written to the file."); +} + +/** + * Write all of the material specifications to the MTL file. + * For consistency of output from run to run (useful for testing), + * the materials are sorted by name before writing. + */ +void MTLWriter::write_materials() +{ + if (mtlmaterials_.size() == 0) { + return; + } + std::sort(mtlmaterials_.begin(), + mtlmaterials_.end(), + [](const MTLMaterial &a, const MTLMaterial &b) { return a.name < b.name; }); + for (const MTLMaterial &mtlmat : mtlmaterials_) { + file_handler_->write<eMTLSyntaxElement::string>("\n"); + file_handler_->write<eMTLSyntaxElement::newmtl>(mtlmat.name); + write_bsdf_properties(mtlmat); + for (const Map<const eMTLSyntaxElement, tex_map_XX>::Item &texture_map : + mtlmat.texture_maps.items()) { + if (!texture_map.value.image_path.empty()) { + write_texture_map(mtlmat, texture_map); + } + } + } +} + +/** + * Add the materials of the given object to MTLWriter, deduping + * against ones that are already there. + * Return a Vector of indices into mtlmaterials_ that hold the MTLMaterial + * that corresponds to each material slot, in order, of the given Object. + * Indexes are returned rather than pointers to the MTLMaterials themselves + * because the mtlmaterials_ Vector may move around when resized. + */ +Vector<int> MTLWriter::add_materials(const OBJMesh &mesh_to_export) +{ + Vector<int> r_mtl_indices; + r_mtl_indices.resize(mesh_to_export.tot_materials()); + for (int16_t i = 0; i < mesh_to_export.tot_materials(); i++) { + const Material *material = mesh_to_export.get_object_material(i); + if (!material) { + r_mtl_indices[i] = -1; + continue; + } + int mtlmat_index = material_map_.lookup_default(material, -1); + if (mtlmat_index != -1) { + r_mtl_indices[i] = mtlmat_index; + } + else { + mtlmaterials_.append(mtlmaterial_for_material(material)); + r_mtl_indices[i] = mtlmaterials_.size() - 1; + material_map_.add_new(material, r_mtl_indices[i]); + } + } + return r_mtl_indices; +} + +const char *MTLWriter::mtlmaterial_name(int index) +{ + if (index < 0 || index >= mtlmaterials_.size()) { + return nullptr; + } + return mtlmaterials_[index].name.c_str(); +} +/** \} */ + +} // namespace blender::io::obj |