### 摘要 unity用的很普遍，现在很多代码还是用c++写的，需要用unity去调用c++的代码。这里介绍了一种unity调用c++ dll的方法，希望有所帮助。 **我采用的软件是Visual Studio 2015和 Unity 5.3.4** ![](https://camo.githubusercontent.com/aa98539db072d8c2ee31c41b73be99801bdcabea/687474703a2f2f696d61676573323031352e636e626c6f67732e636f6d2f626c6f672f313031343039312f3230313630392f313031343039312d32303136303931333132303632323533392d34393837343539362e706e67) ------------ ## 1. 建立VS DLL 工程 ![](https://camo.githubusercontent.com/1555a05a717db8ce6fc7f59b8633e92b74f3be93/687474703a2f2f696d61676573323031352e636e626c6f67732e636f6d2f626c6f672f313031343039312f3230313630392f313031343039312d32303136303931333132303633313836372d3930393138343135302e706e67) ![](https://camo.githubusercontent.com/eb88b21e92537baaea183e1cbfd8956246d63aec/687474703a2f2f696d61676573323031352e636e626c6f67732e636f6d2f626c6f672f313031343039312f3230313630392f313031343039312d32303136303931333132303634343333362d323038343233343839332e706e67) ------------ ## 2. cpp代码编辑 **test.cpp** ```cpp #define EXPORTBUILD #include "test.h" #include _DLLExport int cpp_get_int_value() { return 51; } _DLLExport void cpp_get_int_ptr(int* value) { *value = 52; } _DLLExport void cpp_get_int_ref(int& value) { value = 53; } _DLLExport float cpp_get_float_value() { return 51.1f; } _DLLExport void cpp_get_float_ptr(float* value) { *value = 52.1f; } _DLLExport void cpp_get_float_ref(float& value) { value = 53.1f; } _DLLExport void cpp_get_string_value(char** str_ptr) { char* str = "hello world"; strcpy(*str_ptr, str); return; } struct cpp_struct_one { int value1; float value2; }; _DLLExport void cpp_get_struct_one_value(cpp_struct_one* stu) { stu->value1 = 10; stu->value2 = 10.1f; return; } _DLLExport void cpp_get_struct_one_value2(cpp_struct_one& stu) { stu.value1 = 11; stu.value2 = 11.1f; return; } _DLLExport void cpp_get_struct_one_value3(cpp_struct_one* stu) { stu->value1 = 12; stu->value2 = 12.1f; return; } struct cpp_struct_two { int value1[10]; float value2; }; _DLLExport void cpp_get_struct_two_value(cpp_struct_two* stu, int count) { for (int i = 0; i < count; i++) { stu->value1[i] = i; } stu->value2 = 10.1f; return; } _DLLExport void cpp_get_int_arr1(int* arr, int count) { for (int i = 0; i < count; i++) { arr[i] = i; } return; } _DLLExport void cpp_get_int_arr2(int* arr, int count) { for (int i = 0; i < count; i++) { arr[i] = i; } return; } _DLLExport void cpp_get_int_arr3(int* arr, int count) { for (int i = 0; i < count; i++) { arr[i] = i; } return; } _DLLExport void cpp_set_string_value(char* s) { std::string str = s; printf("str %s length %d", str.c_str(), str.length()); return; } ``` ## 3. 构建Dll 文件 ![](https://camo.githubusercontent.com/e6ffbb686ac7ea5e0c9e71b27ad3db26783ef0cd/687474703a2f2f696d61676573323031352e636e626c6f67732e636f6d2f626c6f672f313031343039312f3230313630392f313031343039312d32303136303931333134313930313339382d313139383237313634392e706e67) ## 4. unity 工程创建在unity在 Assets文件下文件Plugins目录，在目录下方放入Dll文件。要是没有Plugins文件夹，就新建一个。 ![](https://camo.githubusercontent.com/69e36ec1579776e0156105df9aa8776fac1002ad/687474703a2f2f696d61676573323031352e636e626c6f67732e636f6d2f626c6f672f313031343039312f3230313630392f313031343039312d32303136303931333134323034303433302d313039333838343731332e706e67) ## 5. unity 代码编辑这里注意，**Dll文件不需要加后缀 .dll** ```cpp using UnityEngine; using System.Collections; using System.Runtime.InteropServices; using System.Text; using System; public class NewBehaviourScript : MonoBehaviour { [DllImport("cppDll")] private static extern int cpp_get_int_value(); [DllImport("cppDll")] private static extern void cpp_get_int_ptr(ref int value); [DllImport("cppDll")] private static extern void cpp_get_int_ref(ref int value); [DllImport("cppDll")] private static extern float cpp_get_float_value(); [DllImport("cppDll")] private static extern void cpp_get_float_ptr(ref float value); [DllImport("cppDll")] private static extern void cpp_get_float_ref(ref float value); [DllImport("cppDll")] private static extern void cpp_get_string_value(ref StringBuilder ptrStr); [StructLayout(LayoutKind.Sequential)] public struct cpp_struct_one { public int value1; public float value2; }; [DllImport("cppDll")] private static extern void cpp_get_struct_one_value(ref cpp_struct_one stu); [DllImport("cppDll")] private static extern void cpp_get_struct_one_value2(ref cpp_struct_one stu); [DllImport("cppDll")] private static extern void cpp_get_struct_one_value3(IntPtr stu); [StructLayout(LayoutKind.Sequential)] public struct cpp_struct_two { [MarshalAs(UnmanagedType.ByValArray, SizeConst = 32)] public int[] value1; public float value2; }; [DllImport("cppDll")] private static extern void cpp_get_struct_two_value(IntPtr stu, int count); [DllImport("cppDll")] private static extern void cpp_get_int_arr1(ref int arr, int count); [DllImport("cppDll")] private static extern void cpp_get_int_arr2(int[] arr, int count); [DllImport("cppDll")] private static extern void cpp_get_int_arr3(IntPtr arr, int count); [DllImport("cppDll")] private static extern void cpp_set_string_value(string s); // Use this for initialization void Start () { // 获取int类型 int int_value = cpp_get_int_value(); Console.WriteLine("cpp_get_int_value\t " + int_value); // 获取int类型指针 int int_ptr = new int(); cpp_get_int_ptr(ref int_ptr); Console.WriteLine("cpp_get_int_ptr\t " + int_ptr); // 获取int类型引用 int int_ref = new int(); cpp_get_int_ref(ref int_ref); Console.WriteLine("cpp_get_int_ref\t " + int_ref); // 获取float类型 float float_value = cpp_get_float_value(); Console.WriteLine("cpp_get_float_value\t " + float_value); // 获取float类型指针 float float_ptr = new float(); cpp_get_float_ptr(ref float_ptr); Console.WriteLine("cpp_get_float_ptr\t " + float_ptr); // 获取float类型引用 float float_ref = new float(); cpp_get_float_ref(ref float_ref); Console.WriteLine("cpp_get_float_ref\t " + float_ref); // 获取结构体类型 cpp_struct_one stu = new cpp_struct_one(); cpp_get_struct_one_value(ref stu); Console.WriteLine("cpp_get_struct_one_value " + stu.value1 + " " + stu.value2); // 获取结构体类型方法2 cpp_struct_one stu2 = new cpp_struct_one(); cpp_get_struct_one_value2(ref stu2); Console.WriteLine("cpp_get_struct_one_value2 " + stu2.value1 + " " + stu2.value2); // 获取结构体类型方法3 // 使用非托管内存 int cpp_struct_one_size = Marshal.SizeOf(typeof(cpp_struct_one)); IntPtr cpp_struct_one_buffer = Marshal.AllocHGlobal(cpp_struct_one_size); cpp_get_struct_one_value3(cpp_struct_one_buffer); cpp_struct_one stu3 = (cpp_struct_one)Marshal.PtrToStructure(cpp_struct_one_buffer, typeof(cpp_struct_one)); Console.WriteLine("cpp_get_struct_one_value3 " + stu3.value1 + " " + stu3.value2); // 获取结构体类型2(带数组结构体) // 使用非托管内存 int cpp_struct_two_size = Marshal.SizeOf(typeof(cpp_struct_two)); IntPtr cpp_struct_two_buffer = Marshal.AllocHGlobal(cpp_struct_two_size); cpp_get_struct_two_value(cpp_struct_two_buffer, 10); cpp_struct_two stu4 = (cpp_struct_two)Marshal.PtrToStructure(cpp_struct_two_buffer, typeof(cpp_struct_two)); Console.WriteLine("cpp_get_struct_two_value " + stu4.value1[5] + " " + stu3.value2); // 获取字符串 StringBuilder str = new StringBuilder(); cpp_get_string_value(ref str); Console.WriteLine("cpp_get_string_value " + str.ToString()); // 获取int型数组方法1 int[] arr1 = new int[10]; cpp_get_int_arr1(ref arr1[0], arr1.Length); Console.WriteLine("cpp_get_int_arr1 5 " + arr1[5]); // 获取int型数组方法2 int[] arr2 = new int[10]; cpp_get_int_arr2(arr2, arr2.Length); Console.WriteLine("cpp_get_int_arr2 5 " + arr2[5]); // 获取int型数组方法3 int arr3_length = 10; int arr3_size = Marshal.SizeOf(typeof(int)) * arr3_length; IntPtr arr3_buffer = Marshal.AllocHGlobal(arr3_size); cpp_get_int_arr3(arr3_buffer, arr3_length); int arr3_test_value = (int)Marshal.PtrToStructure(arr3_buffer + 5 * Marshal.SizeOf(typeof(int)), typeof(int)); Console.WriteLine("cpp_get_int_arr3 " + arr3_test_value); // 传入字符串 string s = "hello world"; cpp_set_string_value(s); } // Update is called once per frame void Update () { } } ``` unity运行结果 ![](https://camo.githubusercontent.com/b6f013181424c119f052d5e2ca06351935b7f0fe/687474703a2f2f696d61676573323031352e636e626c6f67732e636f6d2f626c6f672f313031343039312f3230313631322f313031343039312d32303136313230323132323634373639332d3535333231303632322e706e67) **项目地址** https://github.com/caimagic/Unity_Call_Cplusplus-s-Dll.git