#include <iostream>
#include <string>
#include <vector>
#include <conio.h>

#include "CL\opencl.h"

int main()
{
    cl_uint platformCount = 0;
    clGetPlatformIDs( 0, 0, &platformCount );

    std::vector<cl_platform_id> platforms( platformCount );
    clGetPlatformIDs( platformCount, platforms.data(), 0 );

    for( auto platformId : platforms )
    {
        size_t vendorLength = 0;
        clGetPlatformInfo( platformId, CL_PLATFORM_VENDOR, 0, nullptr,
            &vendorLength );

        std::vector<char> rawVendor( vendorLength );
        clGetPlatformInfo( platformId, CL_PLATFORM_VENDOR, rawVendor.size(),
            rawVendor.data(), nullptr );

        std::string vendor( rawVendor.data() );

        std::cout << "Detected OpenCL platform: " << vendor << std::endl;
        if( !vendor.compare( "NVIDIA Corporation" ) )
        {
            cl_uint deviceCount = 0;
            clGetDeviceIDs( platformId, CL_DEVICE_TYPE_GPU, 0, 0, &deviceCount );
            std::cout << "  Detected " << deviceCount << " GPU device(s)"
                << std::endl;

            std::vector<cl_device_id> devices( platformCount );
            clGetDeviceIDs( platformId, CL_DEVICE_TYPE_GPU, deviceCount,
                devices.data(), nullptr );

            for( auto deviceId : devices )
            {
                size_t nameLength = 0;
                clGetDeviceInfo( deviceId, CL_DEVICE_NAME, 0, nullptr,
                    &nameLength );

                std::string deviceName( nameLength, 0 );
                clGetDeviceInfo( deviceId, CL_DEVICE_NAME, deviceName.size(),
                    deviceName.data(), nullptr );
                std::cout << "  Device: " << deviceName << std::endl;

                cl_context_properties contextProperties[] = { CL_CONTEXT_PLATFORM, (cl_context_properties)platformId, 0 };
                cl_context context = clCreateContext( contextProperties, (cl_uint)1, &deviceId, 0, 0, nullptr );

                constexpr size_t numVramSize = (size_t)2 * 1024 * 1024 * 1024; // 2 GB

                std::cout << "  Press any key to allocate 2 GB of virtual memory" << std::endl;
                _getch();

                cl_int clResult = CL_SUCCESS;
                cl_mem mem = clCreateBuffer( context, CL_MEM_HOST_NO_ACCESS | CL_MEM_READ_WRITE, numVramSize, 0, &clResult );

                std::cout << "  Press any key to free allocated virtual memory" << std::endl;
                _getch();

                clReleaseMemObject( mem );

                break;
            }
        }
    }

    return 0;
}