將OpenCL和OpenCV一些簡單的方法封裝成DLL，具體OpenCL和OpenCV的配置方法可以參考本人的部落格。
VS2015下安裝與編譯OpenCV原始碼並在VS2015下配置OpenCV環境
VS上執行CUDA，並在NVDIA顯示卡安裝的CUDA中執行OpenCL
1. DLL封裝
（1） 建立DLL工程
新建一個Win32控制檯應用程式，專案名稱為buildopencldll，選擇DLL和空專案。
（2）新建標頭檔案
標頭檔案：createopencldll.h
向動態連結庫新增類的核心程式碼：
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#ifdef CREATEOPENCLDLL_EXPORTS #define CREATEOPENCLDLL_API __declspec(dllexport) #else #define CREATEOPENCLDLL_API __declspec(dllimport) #endif |
為顯式連結做準備的匯出函式：
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extern "C" { CREATEOPENCLDLL_API CreateOpenCLDLL* GetCreateOpenCLDLL(void); typedef CreateOpenCLDLL* (*PFNGetCreateOpenCLDLL)(void); } |
建立類時必須加上CREATEOPENCLDLL_API，如寫成class CREATEOPENCLDLL_APICreateOpenCLDLL 要不然生成不了lib檔案
完整的標頭檔案程式碼如下：
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#pragma once #ifndef _CREATEOPENCLDLL_H_ #define _CREATEOPENCLDLL_H_ #ifdef CREATEOPENCLDLL_EXPORTS #define CREATEOPENCLDLL_API __declspec(dllexport) #else #define CREATEOPENCLDLL_API __declspec(dllimport) #endif #ifdef __APPLE__ #include <OpenCL/cl.h> #else #include <CL/cl.h> #endif class CREATEOPENCLDLL_API CreateOpenCLDLL { public: CreateOpenCLDLL(); ~CreateOpenCLDLL(); // 選擇平臺並建立上下文 cl_context CreateContext(); cl_command_queue CreateCommandQueue(cl_context context, cl_device_id *device); cl_program CreateProgram(cl_context context, cl_device_id device, const char* fileName); bool CreateMemObjects(cl_context context, cl_mem memObjects[3], float *a, float *b); void Cleanup(cl_context context, cl_command_queue commandQueue, cl_program program, cl_kernel kernel, cl_mem memObjects[3]); void Calcaute(); private: cl_context m_context; cl_command_queue m_commandQueue; cl_program m_program; cl_device_id m_device; cl_kernel m_kernel; cl_mem m_memObjects[3]; cl_int m_errNum; }; /* 匯出函式宣告 */ extern "C" { CREATEOPENCLDLL_API CreateOpenCLDLL* GetCreateOpenCLDLL(void); typedef CreateOpenCLDLL* (*PFNGetCreateOpenCLDLL)(void); } #endif |
（3）Cpp檔案：createopencldll.cpp
需要新增：#define CREATEOPENCLDLL_EXPORTS
完整的cpp程式碼如下：
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#define CREATEOPENCLDLL_EXPORTS #include <iostream> #include <fstream> #include <string> #include <vector> #include <sstream> #include "createopencldll.h" using namespace std; const int KArraySize = 1000; CreateOpenCLDLL::CreateOpenCLDLL() { m_context = 0; m_commandQueue = 0; m_program = 0; m_device = 0; m_kernel = 0; m_memObjects[0] = 0; m_memObjects[1] = 0; m_memObjects[2] = 0; m_errNum = 0; } CreateOpenCLDLL::~CreateOpenCLDLL() { } // 選擇平臺並建立上下文 cl_context CreateOpenCLDLL::CreateContext() { cl_int errNum; cl_uint numPlatforms; cl_platform_id firstPlatformId; cl_context context = NULL; //選擇第一個可用的平臺 errNum = clGetPlatformIDs(1, &firstPlatformId, &numPlatforms); if (errNum != CL_SUCCESS || numPlatforms <= 0) { std::cerr << "Failed to find any OpenCL platforms." << std::endl; return NULL; } // 建立一個opencl上下文，成功則使用GUP上下文，否則使用cpu cl_context_properties contextProperties[] = { CL_CONTEXT_PLATFORM, (cl_context_properties)firstPlatformId, 0 }; context = clCreateContextFromType(contextProperties, CL_DEVICE_TYPE_GPU, NULL, NULL, &errNum); if (errNum != CL_SUCCESS) { std::cout << "Could not create GPU context, trying CPU..." << std::endl; context = clCreateContextFromType(contextProperties, CL_DEVICE_TYPE_CPU, NULL, NULL, &errNum); if (errNum != CL_SUCCESS) { std::cerr << "Failed to create an OpenCL GPU or CPU context." << std::endl; return NULL; } } return context; } //選擇第一個可用的裝置並建立一個命令佇列 cl_command_queue CreateOpenCLDLL::CreateCommandQueue(cl_context context, cl_device_id *device) { cl_int errNum; cl_device_id *devices; cl_command_queue commandQueue = NULL; size_t deviceBufferSize = -1; //這個clGetContextInfo獲得裝置緩衝區的大小 errNum = clGetContextInfo(context, CL_CONTEXT_DEVICES, 0, NULL, &deviceBufferSize); if (errNum != CL_SUCCESS) { std::cerr << "Failed call to clGetContextInfo(...,GL_CONTEXT_DEVICES,...)"; return NULL; } if (deviceBufferSize <= 0) { std::cerr << "No devices available."; return NULL; } //為裝置緩衝區分配記憶體，這個clGetContextInfo用來獲得上下文中所有可用的裝置 devices = new cl_device_id[deviceBufferSize / sizeof(cl_device_id)]; errNum = clGetContextInfo(context, CL_CONTEXT_DEVICES, deviceBufferSize, devices, NULL); if (errNum != CL_SUCCESS) { delete[] devices; std::cerr << "Failed to get device IDs"; return NULL; } char deviceName[512]; char deviceVendor[512]; char deviceVersion[512]; errNum = clGetDeviceInfo(devices[0], CL_DEVICE_VENDOR, sizeof(deviceVendor), deviceVendor, NULL); errNum |= clGetDeviceInfo(devices[0], CL_DEVICE_NAME, sizeof(deviceName), deviceName, NULL); errNum |= clGetDeviceInfo(devices[0], CL_DEVICE_VERSION, sizeof(deviceVersion), deviceVersion, NULL); printf("OpenCL Device Vendor = %s, OpenCL Device Name = %s, OpenCL Device Version = %s\n", deviceVendor, deviceName, deviceVersion); // 在這個例子中，我們只選擇第一個可用的裝置。在實際的程式，你可能會使用所有可用的裝置或基於OpenCL裝置查詢選擇效能最高的裝置 commandQueue = clCreateCommandQueue(context, devices[0], 0, NULL); if (commandQueue == NULL) { delete[] devices; std::cerr << "Failed to create commandQueue for device 0"; return NULL; } *device = devices[0]; delete[] devices; return commandQueue; } //從磁碟載入核心原始檔並建立一個程式物件 cl_program CreateOpenCLDLL::CreateProgram(cl_context context, cl_device_id device, const char* fileName) { cl_int errNum; cl_program program; std::ifstream kernelFile(fileName, std::ios::in); if (!kernelFile.is_open()) { std::cerr << "Failed to open file for reading: " << fileName << std::endl; return NULL; } std::ostringstream oss; oss << kernelFile.rdbuf(); std::string srcStdStr = oss.str(); const char *srcStr = srcStdStr.c_str(); //建立程式物件 program = clCreateProgramWithSource(context, 1, (const char**)&srcStr, NULL, NULL); if (program == NULL) { std::cerr << "Failed to create CL program from source." << std::endl; return NULL; } //編譯核心原始碼 errNum = clBuildProgram(program, 0, NULL, NULL, NULL, NULL); if (errNum != CL_SUCCESS) { // 編譯失敗可以通過clGetProgramBuildInfo獲取日誌 char buildLog[16384]; clGetProgramBuildInfo(program, device, CL_PROGRAM_BUILD_LOG, sizeof(buildLog), buildLog, NULL); std::cerr << "Error in kernel: " << std::endl; std::cerr << buildLog; clReleaseProgram(program); return NULL; } return program; } //建立記憶體物件 bool CreateOpenCLDLL::CreateMemObjects(cl_context context, cl_mem memObjects[3],float *a, float *b) { //建立記憶體物件 memObjects[0] = clCreateBuffer(context, CL_MEM_READ_ONLY | CL_MEM_COPY_HOST_PTR, sizeof(float)* KArraySize, a, NULL); memObjects[1] = clCreateBuffer(context, CL_MEM_READ_ONLY | CL_MEM_COPY_HOST_PTR, sizeof(float)* KArraySize, b, NULL); memObjects[2] = clCreateBuffer(context, CL_MEM_READ_WRITE, sizeof(float)* KArraySize, NULL, NULL); if (memObjects[0] == NULL || memObjects[1] == NULL || memObjects[2] == NULL) { std::cerr << "Error creating memory objects." << std::endl; return false; } return true; } //清理任何建立OpenCL的資源 void CreateOpenCLDLL::Cleanup(cl_context context, cl_command_queue commandQueue, cl_program program, cl_kernel kernel, cl_mem memObjects[3]) { for (int i = 0; i < 3; i++) { if (memObjects[i] != 0) clReleaseMemObject(memObjects[i]); } if (commandQueue != 0) clReleaseCommandQueue(commandQueue); if (kernel != 0) clReleaseKernel(kernel); if (program != 0) clReleaseProgram(program); if (context != 0) clReleaseContext(context); } void CreateOpenCLDLL::Calcaute() { // 建立opencl上下文和第一個可用平臺 m_context = CreateContext(); if (m_context == NULL) { std::cerr << "Failed to create OpenCL context." << std::endl; } // 在建立的一個上下文中選擇第一個可用的裝置並建立一個命令佇列 m_commandQueue = CreateCommandQueue(m_context, &m_device); if (m_commandQueue == NULL) { Cleanup(m_context, m_commandQueue, m_program, m_kernel, m_memObjects); } // 建立一個程式物件 HelloWorld.cl kernel source m_program = CreateProgram(m_context, m_device, "HelloWorld.cl"); if (m_program == NULL) { Cleanup(m_context, m_commandQueue, m_program, m_kernel, m_memObjects); } // 建立核心 m_kernel = clCreateKernel(m_program, "hello_kernel", NULL); if (m_kernel == NULL) { std::cerr << "Failed to create kernel" << std::endl; Cleanup(m_context, m_commandQueue, m_program, m_kernel, m_memObjects); } // 建立一個將用作引數核心記憶體中的物件。首先建立將被用來將引數儲存到核心主機儲存器陣列 float result[KArraySize]; float a[KArraySize]; float b[KArraySize]; for (int i = 0; i < KArraySize; i++) { a[i] = (float)i; b[i] = (float)(i * 2); } if (!CreateMemObjects(m_context, m_memObjects, a, b)) { Cleanup(m_context, m_commandQueue, m_program, m_kernel, m_memObjects); } // 設定核心引數、執行核心並讀回結果 m_errNum = clSetKernelArg(m_kernel, 0, sizeof(cl_mem), &m_memObjects[0]); m_errNum |= clSetKernelArg(m_kernel, 1, sizeof(cl_mem), &m_memObjects[1]); m_errNum |= clSetKernelArg(m_kernel, 2, sizeof(cl_mem), &m_memObjects[2]); if (m_errNum != CL_SUCCESS) { std::cerr << "Error setting kernel arguments." << std::endl; Cleanup(m_context, m_commandQueue, m_program, m_kernel, m_memObjects); } size_t globalWorkSize[1] = { KArraySize };//讓之等於陣列的大小 size_t localWorkSize[1] = { 1 }; //讓之等於1 // 利用命令佇列使將在裝置執行的核心排隊 m_errNum = clEnqueueNDRangeKernel(m_commandQueue, m_kernel, 1, NULL, globalWorkSize, localWorkSize, 0, NULL, NULL); if (m_errNum != CL_SUCCESS) { std::cerr << "Error queuing kernel for execution." << std::endl; Cleanup(m_context, m_commandQueue, m_program, m_kernel, m_memObjects); } std::cout << "Executed program succesfully." << std::endl; // Read the output buffer back to the Host m_errNum = clEnqueueReadBuffer(m_commandQueue, m_memObjects[2], CL_TRUE, 0, KArraySize * sizeof(float), result, 0, NULL, NULL); if (m_errNum != CL_SUCCESS) { std::cerr << "Error reading result buffer." << std::endl; Cleanup(m_context, m_commandQueue, m_program, m_kernel, m_memObjects); } //輸出結果 for (int i = 0; i < KArraySize; i++) { std::cout << result[i] << " "; } std::cout << std::endl; std::cout << "Executed program succesfully." << std::endl; Cleanup(m_context, m_commandQueue, m_program, m_kernel, m_memObjects); } /* 匯出函式定義 */ CreateOpenCLDLL* GetCreateOpenCLDLL(void) { CreateOpenCLDLL* pCreateOpenCLDLL = new CreateOpenCLDLL(); return pCreateOpenCLDLL; } |
（4）生成程式碼
按生成後，在的debug或者release資料夾中，會生成相應的DLL檔案和LIB檔案，如下圖生成buildopencldll.dll，buildopencldll.lib
2. C++ 多個類的 DLL 封裝
封裝好一個類之後，在後面的類可以呼叫這個類生成的dll，再封裝新類的dll。具體過程可以參考第1步。
在工程中新增標頭檔案createopencldll.h到新的工程目錄。在debug或者release檔案中複製buildopencldll.lib到新的工程目錄如下：
在專案中，屬性->聯結器->輸入->附加依賴項中，新增buildopencldll.lib
將buildopencldll.dll複製到新工程的debug或者release目錄下。
具體新專案的createopencvdll.h程式碼如下：
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#pragma once #ifdef CREATEOPENCVDLL_EXPORTS #define CREATEOPENCVDLL_API __declspec(dllexport) #else #define CREATEOPENCVDLL_API __declspec(dllimport) #endif #include "createopencldll.h" #include "opencv2\opencv_modules.hpp" #include "opencv2\highgui\highgui.hpp" #include "opencv2\core\core.hpp" using namespace cv; class CREATEOPENCVDLL_API CreateOpenCVDLL { public: CreateOpenCVDLL(); ~CreateOpenCVDLL(); void showImage(); private: Mat m_image; }; |
createopencvdll.cpp程式碼如下：
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#define CREATEOPENCVDLL_EXPORTS #include "createopencvdll.h" CreateOpenCVDLL::CreateOpenCVDLL() { } CreateOpenCVDLL::~CreateOpenCVDLL() { } void CreateOpenCVDLL::showImage() { m_image = imread("1.jpg"); namedWindow("image", CV_WINDOW_AUTOSIZE); imshow("image", m_image); cvWaitKey(0); } |
3. DLL 的呼叫
新建一個win32控制檯應用程式，選擇控制檯應用程式，工程名字為：testdll，新建main函式。
（1）隱式連結方法1：
在工程中新增標頭檔案createopencldll.h到新的工程目錄。在debug或者release檔案中複製buildopencldll.lib到新的工程目錄如下：
在專案中，屬性->聯結器->輸入->附加依賴項中，新增buildopencldll.lib
將buildopencldll.dll複製到新工程的debug或者release目錄下。
測試程式碼如下：
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#include "createopencldll.h" int main() { CreateOpenCLDLL createopencldll; createopencldll.Calcaute(); return 0; } |
結果圖如下：
方法2：
在方法1的基礎下，不新增buildopencldll.lib到附加依賴項中，使用程式碼的方式新增，即在原來的程式碼下多新增：#pragmacomment(lib, “buildopencldll.lib”)程式碼如下：
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#pragma comment(lib, "buildopencldll.lib") #include "createopencldll.h" int main() { CreateOpenCLDLL createopencldll; createopencldll.Calcaute(); return 0; } |
（2）顯式連結
參考部落格：http://blog.csdn.net/chollima/article/details/5324808
這個部落格先定義虛基類，然後到基類等的實現，這樣比較好。
這種方法不需要createopencldll.lib，將createopencldll.dll複製到debug或者release目錄。
具體實現程式碼如下：
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#include <windows.h> #include <cstdio> #include "createopencldll.h" int main() { HMODULE hDll = ::LoadLibrary("buildopencldll.dll"); if (NULL != hDll) { PFNGetCreateOpenCLDLL pFun = (PFNGetCreateOpenCLDLL)::GetProcAddress(hDll, "GetCreateOpenCLDLL"); if (NULL != pFun) { CreateOpenCLDLL* createOpenCLDLL = (*pFun)(); if (NULL != createOpenCLDLL) { createOpenCLDLL->Calcaute(); delete createOpenCLDLL; } } ::FreeLibrary(hDll); } return 0; } |
如果出現錯誤：
錯誤 C2664 “HMODULELoadLibraryW(LPCWSTR)”: 無法將引數 1 從“const char [19]”轉換為“LPCWSTR” bulidopecvdll f:\openclproject\bulidopecvdll\bulidopecvdll\main.cpp 18
進入屬性->常規->字符集，將使用Unicode字符集改為未設定即可。
參考部落格：
http://blog.csdn.net/xiaowei_cqu/article/details/7737682
https://msdn.microsoft.com/zh-cn/library/ms235636
http://www.cnblogs.com/weidiao/p/5013889.html
http://blog.csdn.net/xiamentingtao/article/details/51052918
http://www.cnblogs.com/laogao/archive/2012/12/07/2806528.html