loop_vert_read

    std::unordered_map<Vertex,u32> individVerts{};

    u32 verts_count {0};

    for(const auto& shape : shapes){
        for(const auto& ind : shape.mesh.indices){
            Vertex vert{};

            vert.pos = {
                attr.vertices[3 * ind.vertex_index + 0],
                attr.vertices[3 * ind.vertex_index + 1],
                attr.vertices[3 * ind.vertex_index + 2],
            };

            vert.uvco = {
                      attr.texcoords[2 * ind.texcoord_index + 0],
                1.f - attr.texcoords[2 * ind.texcoord_index + 1]
            };

            vert.norm = {
                attr.normals[3 * ind.normal_index + 0],
                attr.normals[3 * ind.normal_index + 1],
                attr.normals[3 * ind.normal_index + 2],
            };

            if(individVerts.count(vert) == 0){
                individVerts[vert] = static_cast<u32>(obju->verts.size());
                obju->verts        . push_back(vert);
            }

            obju->inds.push_back(individVerts[vert]);
            verts_count++;

            size_t size = shape.mesh.indices.size();

            if(verts_count % 3 == 0){
                u64 ind_1 = obju->inds[verts_count - 3];
                u64 ind_2 = obju->inds[verts_count - 2];
                u64 ind_3 = obju->inds[verts_count - 1];

                Vertex vert_1 = obju->verts[ind_1];
                Vertex vert_2 = obju->verts[ind_2];
                Vertex vert_3 = obju->verts[ind_3];

                glm::vec3 E_1 = vert_2.pos - vert_1.pos;
                glm::vec3 E_2 = vert_3.pos - vert_1.pos;

                glm::vec2 dUV_1 = vert_2.uvco - vert_1.uvco;
                glm::vec2 dUV_2 = vert_3.uvco - vert_1.uvco;

                f32 f = 1.0f / (dUV_1.x * dUV_2.y - dUV_2.x * dUV_1.y);

                glm::vec3 tan;

                tan.x = f * (dUV_2.y * E_1.x - dUV_1.y * E_2.x);
                tan.y = f * (dUV_2.y * E_1.y - dUV_1.y * E_2.y);
                tan.z = f * (dUV_2.y * E_1.z - dUV_1.y * E_2.z);

                glm::vec3 btan;

                btan.x = f * (-dUV_2.x * E_1.x + dUV_1.x * E_2.x);
                btan.y = f * (-dUV_2.x * E_1.y + dUV_1.x * E_2.y);
                btan.z = f * (-dUV_2.x * E_1.z + dUV_1.x * E_2.z);

                obju->verts[ind_1].tan = tan;
                obju->verts[ind_2].tan = tan;
                obju->verts[ind_3].tan = tan;

                obju->verts[ind_1].btan = btan;
                obju->verts[ind_2].btan = btan;
                obju->verts[ind_3].btan = btan;
            }
        }
    }