OpenCL example C++

cl_sample

#include <iostream>
#include <CL/cl.hpp>

#include <QVector>

int main()
{
    std::vector<cl::Platform> all_platforms;
    cl::Platform::get(&all_platforms);
    if (all_platforms.empty())
    {
        std::cout << "No platform found" << std::endl;
        exit(1);
    }

    cl::Platform default_platform = all_platforms[0];
    std::cout << "Using platform: " << default_platform.getInfo<CL_PLATFORM_NAME>() << std::endl;

    std::vector<cl::Device> all_devices;
    default_platform.getDevices(CL_DEVICE_TYPE_ALL, &all_devices);
    if (all_devices.empty())
    {
        std::cout << "No device found" << std::endl;
        exit(1);
    }

    cl::Device default_device = all_devices[0];
    std::cout << "Using device: " << default_device.getInfo<CL_DEVICE_NAME>() << std::endl;

    cl::Context context({default_device});

    cl::Program::Sources sources;

    std::string kernel_code = "void kernel simple_add(global const int *A, global int *B) {"
                              "     B[get_global_id(0)] = A[get_global_id(0)] * 3;"
                              "}";

    sources.push_back({kernel_code.c_str(), kernel_code.length()});

    cl::Program program(context, sources);

    if (program.build({default_device}) != CL_SUCCESS)
    {
        std::cout << "Error building: " << program.getBuildInfo<CL_PROGRAM_BUILD_LOG>(default_device) << std::endl;
        exit(1);
    }

    cl::Buffer buffer_A(context, CL_MEM_READ_WRITE, sizeof(int) * 10);
    cl::Buffer buffer_B(context, CL_MEM_READ_WRITE, sizeof(int) * 10);

    //change the array to vector
    QVector<int> A;
    for (int i = 0; i < 10; ++i)
        A.push_back(i);

    cl::CommandQueue queue(context, default_device);

    queue.enqueueWriteBuffer(buffer_A, CL_TRUE, 0, sizeof(int) * 10, A.data());

    cl::Kernel kernel_add(program, "simple_add");
    kernel_add.setArg(0, buffer_A);
    kernel_add.setArg(1, buffer_B);
    queue.enqueueNDRangeKernel(kernel_add, cl::NullRange, cl::NDRange(10), cl::NullRange);
    queue.finish();

    //change the array to vector
    QVector<int> C;
    C.resize(A.size());

    queue.enqueueReadBuffer(buffer_B, CL_TRUE, 0, sizeof(int)*10, C.data());

    std::cout << "Results: " << std::endl;
    for (int i = 0; i < 10; ++i)
    {
        std::cout << C[i] << "\t";
    }
    std::cout << std::endl;

    exit(0);
    return 0;
}