cpp使用assimp库将stl文件转换为obj文件完整代码

ASSIMP是一个开源的跨平台库，用于加载各种3D模型格式，包括STL（标准三角形文件）。它允许你在C++项目中处理模型数据。以下是使用ASSIMP将STL文件转换为OBJ文件的一个简化的示例代码片段：

#include <assimp/Importer.hpp>
#include <assimp/scene.h>
#include <assimp/postprocess.h>

// 假设你已经包含了必要的头文件，并设置了ASSIMP路径

void convertStlToObj(const std::string& stl_file_path, const std::string& obj_output_path) {
    // 初始化ASSIMP的导入器
    Assimp::Importer importer;

    // 加载STL文件
    const aiScene* scene = nullptr;
    if (!importer.ReadFile(stl_file_path, aiProcess_Triangulate | aiProcess_FlipUVs)) { // aiProcess_Triangulate使面片更规则
        std::cerr << "Failed to load STL file: " << importer.GetErrorString() << std::endl;
        return;
    }

    scene = importer.ReadFile(stl_file_path, // Load with triangulation
        aiProcess_Triangulate | aiProcess_FlipUVs | aiProcess_GenSmoothNormals); // Add smooth normals for OBJ format

    if (!scene || scene->mFlags & AI_SCENE_FLAGS_INCOMPLETE) {
        std::cerr << "Incomplete or corrupted model: " << importer.GetErrorString() << std::endl;
        return;
    }

    // 创建一个新的OBJ文件流
    std::ofstream output(obj_output_path);
    if (!output.is_open()) {
        std::cerr << "Failed to open output OBJ file" << std::endl;
        return;
    }

    // 输出基本的OBJ格式头部信息
    output << "mtllib " << stl_file_path.substr(0, stl_file_path.find_last_of(".")) + ".mtl\n";
    output << "o " << stl_file_path.substr(0, stl_file_path.find_last_of(".")); // Object name

    // 遍历并输出每个顶点、面等
    for (unsigned int i = 0; i < scene->mNumMeshes; ++i) {
        const aiMesh* mesh = scene->mMeshes[i];
        for (unsigned int j = 0; j < mesh->mNumVertices; ++j) {
            aiVector3D vertex = mesh->mVertices[j];
            output << "v " << vertex.x << " " << vertex.y << " " << vertex.z << "\n"; // Vertex coordinates
        }
        for (unsigned int k = 0; k < mesh->mNumFaces; ++k) {
            const aiFace& face = mesh->mFaces[k];
            output << "f " << face.mIndices[0] + 1 << " " << face.mIndices[1] + 1 << " " << face.mIndices[2] + 1 << "\n"; // Triangles indices
        }
    }

    // 关闭文件
    output.close();
}