学步园

       在opencl编程中，很多时候需要初始化很多东西，比如查询设备，选择计算设备，初始化上下文，构建程序和编译内核程序。如果每次都重写写一遍这些过程，就会感动很繁琐，所以，我就简单封装了几个函数，用于我的opencl编程中。关于从文本文件构建opencl程序在OpenCL从文本文件构建程序对象已经讲解，下面就给出初始化opencl，以及构建程序和编译内核程序的源代码：

void OpenCLInit(cl_platform_id *clPlatform ,cl_device_id *clDevice,cl_context *clContext)
{
	cl_uint numPlatforms = 0;   //GPU计算平台个数
	cl_platform_id platform = NULL;
	clGetPlatformIDs(0,NULL,&numPlatforms);

	//获得平台列表
	cl_platform_id * platforms = (cl_platform_id*)malloc(numPlatforms * sizeof(cl_platform_id));
	clGetPlatformIDs (numPlatforms, platforms, NULL);

	//轮询各个opencl设备
	for (cl_uint i = 0; i < numPlatforms; i ++)
	{
		char pBuf[100];
		clGetPlatformInfo(platforms[i],CL_PLATFORM_VERSION,sizeof(pBuf),pBuf,NULL);
		printf("%s\n",pBuf);
		platform = platforms[i];
		//break;
	}

	*clPlatform	= platform;

	free(platforms);

	cl_int status = 0;

	//获得GPU设备
	cl_device_id device;
	status = clGetDeviceIDs(platform, CL_DEVICE_TYPE_GPU, 1, &device, NULL);
	*clDevice = device;

	//生成上下文
	cl_context context = clCreateContext(0, 1, &device, NULL, NULL, &status);
	*clContext = context;


} 

构建程序的函数封装如下：

void BuildKernel(cl_platform_id platform ,
				 cl_device_id device,
				 cl_context context,
				 cl_program *clProgram,
				 cl_command_queue *clCommandQueue)
{
	cl_int status = 0;
	//装载内核程序
	size_t szKernelLength = 0;

	const char* kernelSourceCode = LoadProgSource(cSourceFile, "", &szKernelLength);  

	cl_program program = clCreateProgramWithSource(context,1,&kernelSourceCode,&szKernelLength,&status);
	*clProgram = program;

	//为所有指定的设备生成CL_program
	status = clBuildProgram(program,1,&device,NULL,NULL,NULL);  
	size_t len = 0;
	char buf[2048];
	if (status != CL_SUCCESS)
	{
		status = clGetProgramBuildInfo(program,device,CL_PROGRAM_BUILD_LOG,sizeof(buf),buf,&len);
		printf("%s\n", buf);
	}

	//创建一个opencl命令队列
	*clCommandQueue = clCreateCommandQueue(context,device,0,&status);
}

希望对大家有用