进程间通讯方式：共享内存，管道(linux)，udp通讯（若是在同一台电脑上通过udp通讯，那么它并没有经过网络，而是利用了网卡上的一块内存，而且非常可靠。）
这是项目中用到的一处共享内存，别人写的。记录一下，让每个看似毫无意义的项目都能吸收到一点有用的东西。
项目中使用到的地方：服务器要发送数据给unity，但是接收数据的格式是需要以固定的MFC（c/c++）代码接收。然后就在MFC代码中增加一处共享内存，作为中转站，unity读取这处共享内存获得数据。
0.前置准备
| 句柄数据结构
typedef struct semps
{
HANDLE hMFCWrite; //声明信号量变量
HANDLE hU3DRead; //声明信号量变量
HANDLE hU3DWrite; //声明信号量变量
HANDLE hMFCRead; //声明信号量变量
char *pBuf;
CMainFrame *mFrm;
}Semps;
Semps mSemp;
HANDLE hMapFile;
1.实例化共享内存
image.png
ProcessMsg::ProcessMsg(CMainFrame *frm)
{
mSemp.hMFCWrite = CreateSemaphoreA(NULL,1,1,"WriteMap_1");
mSemp.hU3DRead = CreateSemaphoreA(NULL,0,1,"ReadMap_1"); //第二各参数为0，代表进程创建信号量之时便声明了对该信号量的占用
mSemp.hU3DWrite = CreateSemaphoreA(NULL,1,1,"WriteMap_2");
mSemp.hMFCRead = CreateSemaphoreA(NULL,0,1,"ReadMap_2"); //第二各参数为0，代表进程创建信号量之时便声明了对该信号量的占用
//创建共享内存区
char szName[] = "shareMemory"; // 共享内存的名字
// 创建共享文件句柄
hMapFile = CreateFileMapping(
INVALID_HANDLE_VALUE, // 物理文件句柄
NULL, // 默认安全级别
PAGE_READWRITE, // 可读可写
0, // 高位文件大小
BUF_SIZE, // 地位文件大小
szName // 共享内存名称
);
mSemp.pBuf = (char *)MapViewOfFile(
hMapFile, // 共享内存的句柄
FILE_MAP_ALL_ACCESS, // 可读写许可
0,
0,
BUF_SIZE
);
mSemp.mFrm = frm;
AfxBeginThread((AFX_THREADPROC)ThreadProc,(LPVOID)&mSemp,THREAD_PRIORITY_IDLE);
}
Tips :
https://docs.microsoft.com/zh-cn/windows/desktop/api/winbase/nf-winbase-createsemaphorea
https://blog.csdn.net/educast/article/details/8477294
- 由上图可知，此时已经创建好了共享内存文件（通过CreateFileMapping），并完成映射（通过MapViewOfFile），接下来就是要弄unity里面连接映射的地方了。
2.MFC向共享内存写入数据
//发送消息到u3d
void ProcessMsg::SendMsgToU3D(char *str){
strncpy(mSemp.pBuf, str, BUF_SIZE);
//strncpy(mSemp.pBuf, str, BUF_SIZE - 1);
//mSemp.pBuf[BUF_SIZE - 1] = '\0';
//放u3d读
//ReleaseSemaphore(mSemp.hU3DRead,1,0);
//放u3d开写
//ReleaseSemaphore(mSemp.hU3DWrite,1,0);
}
3.unity连接映射地址
image.png
Ps：固定格式代码
const int INVALID_HANDLE_VALUE = -1;
const int PAGE_READWRITE = 0x04;
bool _loadingRedStartMap = false;
//共享内存
[DllImport("Kernel32.dll", EntryPoint = "CreateFileMapping")]
private static extern IntPtr CreateFileMapping(IntPtr hFile, //HANDLE hFile,
UInt32 lpAttributes,//LPSECURITY_ATTRIBUTES lpAttributes, //0
UInt32 flProtect,//DWORD flProtect
UInt32 dwMaximumSizeHigh,//DWORD dwMaximumSizeHigh,
UInt32 dwMaximumSizeLow,//DWORD dwMaximumSizeLow,
string lpName//LPCTSTR lpName
);
[DllImport("Kernel32.dll", EntryPoint = "OpenFileMapping")]
private static extern IntPtr OpenFileMapping(
UInt32 dwDesiredAccess,//DWORD dwDesiredAccess,
int bInheritHandle,//BOOL bInheritHandle,
string lpName//LPCTSTR lpName
);
const int FILE_MAP_ALL_ACCESS = 0x0002;
const int FILE_MAP_WRITE = 0x0002;
[DllImport("Kernel32.dll", EntryPoint = "MapViewOfFile")]
private static extern IntPtr MapViewOfFile(
IntPtr hFileMappingObject,//HANDLE hFileMappingObject,
UInt32 dwDesiredAccess,//DWORD dwDesiredAccess
UInt32 dwFileOffsetHight,//DWORD dwFileOffsetHigh,
UInt32 dwFileOffsetLow,//DWORD dwFileOffsetLow,
UInt32 dwNumberOfBytesToMap//SIZE_T dwNumberOfBytesToMap
);
[DllImport("Kernel32.dll", EntryPoint = "UnmapViewOfFile")]
private static extern int UnmapViewOfFile(IntPtr lpBaseAddress);
[DllImport("Kernel32.dll", EntryPoint = "CloseHandle")]
private static extern int CloseHandle(IntPtr hObject);
[DllImport("Kernel32.dll", EntryPoint = "CreateSemaphoreA")]
private static extern IntPtr CreateSemaphoreA(
UInt32 lpSemaphoreAttributes, // SD
UInt32 lInitialCount, // initial count
UInt32 lMaximumCount, // maximum count
string lpName// object name
);
[DllImport("Kernel32.dll", EntryPoint = "OpenSemaphoreA")]
private static extern IntPtr OpenSemaphoreA(
UInt32 dwDesiredAccess, // access 0x1F0003
int bInheritHandle, // inheritance option
string lpName // object name
);
[DllImport("Kernel32.dll", EntryPoint = "ReleaseSemaphore")]
private static extern int ReleaseSemaphore(
IntPtr hSemaphore,
UInt32 lReleaseCount,
Int32 lpPreviousCount
);
[DllImport("Kernel32.dll", EntryPoint = "WaitForSingleObject")]
private static extern UInt32 WaitForSingleObject(
IntPtr hHandle,
UInt32 dwMilliseconds
);
private IntPtr handle; //文件句柄
private IntPtr addr; //共享内存地址
IntPtr hMFCWrite;
IntPtr hU3DRead;
IntPtr hU3DWrite;
IntPtr hMFCRead;
uint mapLength; //共享内存长
// Process pMFC; //程序
// pMFC = Process.Start(Application.streamingAssetsPath + "\\MFC\\MFC_Client.exe");
// StartCoroutine(WaitToInit(0.5f));
4.Unity数据读取(注意，使用共享内存时有些地方需要上锁)：
image.png
//不安全的代码在项目生成的选项中选中允许不安全代码
static unsafe void byteCopy(byte[] dst, IntPtr src)
{
fixed (byte* pDst = dst)
{
byte* pdst = pDst;
byte* psrc = (byte*)src;
while ((*pdst++ = *psrc++) != '\0')
;
}
}
5.Unity数据发送
image.png
static unsafe void Copy(byte[] byteSrc, IntPtr dst)
{
fixed (byte* pSrc = byteSrc)
{
byte* pDst = (byte*)dst;
byte* psrc = pSrc;
for (int i = 0; i < byteSrc.Length; i++)
{
*pDst = *psrc;
pDst++;
psrc++;
}
}
}
1.MFC
5.结束的时候要做点事
image.png
2.Unity
void OnApplicationQuit()
{
if (sw != null)
{
sw.Close();
}
if (fs != null)
{
fs.Close();
}
if (isLocalTest)
{
return;
}
ReleaseSemaphore(hU3DRead, 1, 0); //不调这一句的话，关闭unity时会卡死
//清空内存
byte[] sendStr = Encoding.Default.GetBytes("" + '\0');
//如果要是超长的话，应另外处理，最好是分配足够的内存
if (sendStr.Length < mapLength)
{
Copy(sendStr, addr);
}
//关闭线程
if (threadRead != null)
{
threadRead.Interrupt();
threadRead.Abort();
}
//关闭MFC进程
if (pMFC != null)
{
pMFC.Kill();
}
//UnityEngine.Debug.Log("关闭U3D");
if (addr != null)
{
UnmapViewOfFile(addr);
}
if (handle != null)
{
CloseHandle(handle);
}
if (hU3DWrite != null)
{
CloseHandle(hU3DWrite);
}
if (hMFCRead != null)
{
CloseHandle(hMFCRead);
}
if (hMFCWrite != null)
{
CloseHandle(hMFCWrite);
}
if (hU3DRead != null)
{
CloseHandle(hU3DRead);
}
}
