.. _program_listing_file_Src_GraphicsEngineVulkan_scene_ObjLoader.cpp:

Program Listing for File ObjLoader.cpp
======================================

|exhale_lsh| :ref:`Return to documentation for file <file_Src_GraphicsEngineVulkan_scene_ObjLoader.cpp>` (``Src/GraphicsEngineVulkan/scene/ObjLoader.cpp``)

.. |exhale_lsh| unicode:: U+021B0 .. UPWARDS ARROW WITH TIP LEFTWARDS

.. code-block:: cpp

   #include "ObjLoader.hpp"
   #define TINYOBJLOADER_IMPLEMENTATION
   #include <tiny_obj_loader.h>
   
   #include "util/File.hpp"
   #include <iostream>
   #include <unordered_map>
   
   using namespace Kataglyphis;
   
   ObjLoader::ObjLoader(VulkanDevice *device, VkQueue transfer_queue, VkCommandPool command_pool)
   {
       this->device = device;
       this->transfer_queue = transfer_queue;
       this->command_pool = command_pool;
   }
   
   std::shared_ptr<Model> ObjLoader::loadModel(const std::string &modelFile)
   {
       // the model we want to load
       std::shared_ptr<Model> new_model = std::make_shared<Model>(device);
   
       // first load txtures from model
       std::vector<std::string> textureNames = loadTexturesAndMaterials(modelFile);
       std::vector<int> matToTex(textureNames.size());
   
       // now that we have the names lets create the vulkan side of textures
       for (size_t i = 0; i < textureNames.size(); i++) {
           // If material had no texture, set '0' to indicate no texture, texture 0
           // will be reserved for a default texture
           if (!textureNames[i].empty()) {
               // Otherwise, create texture and set value to index of new texture
               Texture texture;
               texture.createFromFile(device, command_pool, textureNames[i]);
               new_model->addTexture(texture);
               matToTex[i] = new_model->getTextureCount();
   
           } else {
               matToTex[i] = 0;
           }
       }
   
       loadVertices(modelFile);
   
       new_model->add_new_mesh(device, transfer_queue, command_pool, vertices, indices, materialIndex, this->materials);
   
       return new_model;
   }
   
   std::vector<std::string> ObjLoader::loadTexturesAndMaterials(const std::string &modelFile)
   {
       tinyobj::ObjReaderConfig reader_config;
       tinyobj::ObjReader reader;
   
       if (!reader.ParseFromFile(modelFile, reader_config)) {
           if (!reader.Error().empty()) { std::cerr << "TinyObjReader: " << reader.Error(); }
           exit(EXIT_FAILURE);
       }
   
       if (!reader.Warning().empty()) { std::cout << "TinyObjReader: " << reader.Warning(); }
   
       auto &tol_materials = reader.GetMaterials();
       textures.reserve(tol_materials.size());
   
       int texture_id = 0;
   
       // we now iterate over all materials to get diffuse textures
       for (size_t i = 0; i < tol_materials.size(); i++) {
           const tinyobj::material_t *mp = &tol_materials[i];
           ObjMaterial material{};
           material.ambient = glm::vec3(mp->ambient[0], mp->ambient[1], mp->ambient[2]);
           material.diffuse = glm::vec3(mp->diffuse[0], mp->diffuse[1], mp->diffuse[2]);
           material.specular = glm::vec3(mp->specular[0], mp->specular[1], mp->specular[2]);
           material.emission = glm::vec3(mp->emission[0], mp->emission[1], mp->emission[2]);
           material.transmittance = glm::vec3(mp->transmittance[0], mp->transmittance[1], mp->transmittance[2]);
           material.dissolve = mp->dissolve;
           material.ior = mp->ior;
           material.shininess = mp->shininess;
           material.illum = mp->illum;
   
           if (mp->diffuse_texname.length() > 0) {
               std::string relative_texture_filename = mp->diffuse_texname;
               File model_file(modelFile);
               std::string texture_filename = model_file.getBaseDir() + "/textures/" + relative_texture_filename;
   
               textures.push_back(texture_filename);
               material.textureID = texture_id;
               texture_id++;
   
           } else {
               material.textureID = 0;
               textures.push_back("");
           }
   
           materials.push_back(material);
       }
   
       // for the case no .mtl file is given place some random standard material ...
       if (tol_materials.empty()) { materials.emplace_back(ObjMaterial()); }
   
       return textures;
   }
   
   void ObjLoader::loadVertices(const std::string &fileName)
   {
       tinyobj::ObjReaderConfig reader_config;
       // reader_config.mtl_search_path = ""; // Path to material files
   
       tinyobj::ObjReader reader;
   
       if (!reader.ParseFromFile(fileName, reader_config)) {
           if (!reader.Error().empty()) { std::cerr << "TinyObjReader: " << reader.Error(); }
           exit(EXIT_FAILURE);
       }
   
       if (!reader.Warning().empty()) { std::cout << "TinyObjReader: " << reader.Warning(); }
   
       auto &attrib = reader.GetAttrib();
       auto &shapes = reader.GetShapes();
       auto &materials = reader.GetMaterials();
   
       std::unordered_map<Vertex, uint32_t> vertices_map{};
   
       // Loop over shapes
       for (size_t s = 0; s < shapes.size(); s++) {
           // prepare for enlargement
           vertices.reserve(shapes[s].mesh.indices.size() + vertices.size());
           indices.reserve(shapes[s].mesh.indices.size() + indices.size());
   
           // Loop over faces(polygon)
           size_t index_offset = 0;
           for (size_t f = 0; f < shapes[s].mesh.num_face_vertices.size(); f++) {
               size_t fv = size_t(shapes[s].mesh.num_face_vertices[f]);
   
               // Loop over vertices in the face.
               for (size_t v = 0; v < fv; v++) {
                   // access to vertex
                   tinyobj::index_t idx = shapes[s].mesh.indices[index_offset + v];
                   tinyobj::real_t vx = attrib.vertices[3 * size_t(idx.vertex_index) + 0];
                   tinyobj::real_t vy = attrib.vertices[3 * size_t(idx.vertex_index) + 1];
                   tinyobj::real_t vz = attrib.vertices[3 * size_t(idx.vertex_index) + 2];
                   glm::vec3 pos = { vx, vy, vz };
   
                   glm::vec3 normals(0.0f);
                   // Check if `normal_index` is zero or positive. negative = no normal
                   // data
                   if (idx.normal_index >= 0 && !attrib.normals.empty()) {
                       tinyobj::real_t nx = attrib.normals[3 * size_t(idx.normal_index) + 0];
                       tinyobj::real_t ny = attrib.normals[3 * size_t(idx.normal_index) + 1];
                       tinyobj::real_t nz = attrib.normals[3 * size_t(idx.normal_index) + 2];
                       normals = glm::vec3(nx, ny, nz);
                   }
   
                   glm::vec3 color(-1.f);
                   if (!attrib.colors.empty()) {
                       tinyobj::real_t red = attrib.colors[3 * size_t(idx.vertex_index) + 0];
                       tinyobj::real_t green = attrib.colors[3 * size_t(idx.vertex_index) + 1];
                       tinyobj::real_t blue = attrib.colors[3 * size_t(idx.vertex_index) + 2];
                       color = glm::vec3(red, green, blue);
                   }
   
                   glm::vec2 tex_coords(0.0f);
                   // Check if `texcoord_index` is zero or positive. negative = no texcoord
                   // data
                   if (idx.texcoord_index >= 0 && !attrib.texcoords.empty()) {
                       tinyobj::real_t tx = attrib.texcoords[2 * size_t(idx.texcoord_index) + 0];
                       // flip y coordinate !!
                       tinyobj::real_t ty = 1.f - attrib.texcoords[2 * size_t(idx.texcoord_index) + 1];
                       tex_coords = glm::vec2(tx, ty);
                   }
   
                   Vertex vert{ pos, normals, color, tex_coords };
   
                   if (vertices_map.count(vert) == 0) {
                       vertices_map[vert] = vertices.size();
                       vertices.push_back(vert);
                   }
   
                   indices.push_back(vertices_map[vert]);
               }
   
               index_offset += fv;
   
               // per-face material; face usually is triangle
               // matToTex[shapes[s].mesh.material_ids[f]]
               materialIndex.push_back(shapes[s].mesh.material_ids[f]);
           }
       }
   
       // precompute normals if no provided
       if (attrib.normals.empty()) {
           for (size_t i = 0; i < indices.size(); i += 3) {
               Vertex &v0 = vertices[indices[i + 0]];
               Vertex &v1 = vertices[indices[i + 1]];
               Vertex &v2 = vertices[indices[i + 2]];
   
               glm::vec3 n = glm::normalize(glm::cross((v1.pos - v0.pos), (v2.pos - v0.pos)));
               v0.normal = n;
               v1.normal = n;
               v2.normal = n;
           }
       }
   }