model.cpp

/*
** ETIB PROJECT, 2026
** xider
** File description:
** model
*/
 
#include <utility/graphic/model.hpp>
 
namespace utility::graphic
{
    Model::Model(std::shared_ptr<utility::File> modelAsset, const PoseF &pose,
                 uint32_t materialID)
        : Renderable(pose, Color32Bit())
        , _materialID(materialID)
    {
        std::string extension =
            modelAsset->path().substr(modelAsset->path().find_last_of(".") + 1);
 
        if (extension == "obj") {
            loadOBJ(modelAsset);
            _type = ModelType::OBJ;
        } else if (extension == "fbx") {
            getLogger().warning()
                << "FBX loading not implemented yet. Skipping model loading.";
            // loadFBX(modelAsset); // Not implemented yet
            _type = ModelType::FBX;
        } else if (extension == "gltf" || extension == "glb") {
            getLogger().warning()
                << "GLTF loading not implemented yet. Skipping model loading.";
            // loadGLTF(modelAsset); // Not implemented yet
            _type = ModelType::GLTF;
        } else {
            throw std::runtime_error("Unsupported model format: " + extension);
        }
    }
 
    Model::Model(std::shared_ptr<utility::File> modelAsset, ModelType modelType,
                 const PoseF &pose, uint32_t materialID)
        : Renderable(pose, Color32Bit())
        , _materialID(materialID)
    {
        _type = modelType;
 
        switch (modelType) {
            case ModelType::OBJ:
                loadOBJ(modelAsset);
                break;
            case ModelType::FBX:
                getLogger().warning() << "FBX loading not implemented yet. "
                                         "Skipping model loading.";
                // loadFBX(modelAsset); // Not implemented yet
                break;
            case ModelType::GLTF:
                getLogger().warning() << "GLTF loading not implemented yet. "
                                         "Skipping model loading.";
                // loadGLTF(modelAsset); // Not implemented yet
                break;
            default:
                throw std::runtime_error("Unsupported model type");
        }
    }
 
    // Public methods //
 
    Model::ModelType Model::type() const
    {
        return _type;
    }
 
    utility::graphic::SizeF Model::computeBoundingSize(void)
    {
        return _boundingBox;
    }
 
    uint32_t Model::getMaterialID(void) const
    {
        return _materialID;
    }
 
    // Protected methods //
 
    void Model::loadOBJ(std::shared_ptr<utility::File> modelAsset)
    {
        std::vector<VertexF> vertices;
        std::vector<uint32_t> indices;
 
        // Bounding box calculation
        float minX = std::numeric_limits<float>::max();
        float minY = std::numeric_limits<float>::max();
        float minZ = std::numeric_limits<float>::max();
        float maxX = std::numeric_limits<float>::lowest();
        float maxY = std::numeric_limits<float>::lowest();
        float maxZ = std::numeric_limits<float>::lowest();
 
        tinyobj::attrib_t attrib;
        std::vector<tinyobj::shape_t> shapes;
        std::vector<tinyobj::material_t> materials;
        std::string warn;
        std::string err;
        std::istringstream input(modelAsset->content());
 
        bool ret = tinyobj::LoadObj(&attrib, &shapes, &materials, &warn, &err,
                                    &input, nullptr, true);
 
        if (!ret) {
            throw std::runtime_error("Failed to load/parse .obj. " + err);
        }
        for (const auto &shape: shapes) {
            for (const auto &index: shape.mesh.indices) {
                if (index.vertex_index < 0) {
                    continue;
                }
 
                const size_t vertexBase =
                    static_cast<size_t>(index.vertex_index) * 3;
                if (vertexBase + 2 >= attrib.vertices.size()) {
                    continue;
                }
 
                // Vertices are kept in local (object) space: the world
                // transform is supplied per instance through the model matrix
                // (see utility::graphic::poseToMatrix).
                utility::graphic::VertexF vertex {};
                vertex.setPosition(utility::graphic::PositionF(
                    attrib.vertices[vertexBase + 0],
                    attrib.vertices[vertexBase + 1],
                    attrib.vertices[vertexBase + 2]));
 
                if (index.texcoord_index >= 0) {
                    const size_t texcoordBase =
                        static_cast<size_t>(index.texcoord_index) * 2;
                    if (texcoordBase + 1 < attrib.texcoords.size()) {
                        vertex.setTextureCoordinates(utility::math::Vector2F(
                            { attrib.texcoords[texcoordBase + 0],
                              attrib.texcoords[texcoordBase + 1] }));
                    }
                }
 
                if (index.normal_index >= 0) {
                    const size_t normalBase =
                        static_cast<size_t>(index.normal_index) * 3;
                    if (normalBase + 2 < attrib.normals.size()) {
                        vertex.setNormal(utility::math::Vector3F(
                            { attrib.normals[normalBase + 0],
                              attrib.normals[normalBase + 1],
                              attrib.normals[normalBase + 2] }));
                    }
                }
 
                vertex.setColor(
                    utility::graphic::Color32Bit(255, 255, 255, 255));
 
                if (vertices.size() >= static_cast<size_t>(
                        std::numeric_limits<uint32_t>::max())) {
                    throw std::runtime_error(
                        "Too many vertices for uint32_t indices");
                }
 
                minX = std::min(minX, attrib.vertices[vertexBase + 0]);
                minY = std::min(minY, attrib.vertices[vertexBase + 1]);
                minZ = std::min(minZ, attrib.vertices[vertexBase + 2]);
                maxX = std::max(maxX, attrib.vertices[vertexBase + 0]);
                maxY = std::max(maxY, attrib.vertices[vertexBase + 1]);
                maxZ = std::max(maxZ, attrib.vertices[vertexBase + 2]);
 
                const uint32_t newIndex =
                    static_cast<uint32_t>(vertices.size());
                vertices.push_back(vertex);
                indices.push_back(newIndex);
            }
        }
 
        _meshes.clear();
        if (!vertices.empty() && !indices.empty()) {
            _meshes.push_back(std::make_shared<Mesh>(vertices, indices));
        }
        _boundingBox = SizeF(maxX - minX, maxY - minY, maxZ - minZ);
    }
}    // namespace utility::graphic