/*OpenCLSquares.cpp :calculates the squares of each element in an array
The source code is taken from 
http://simpleopencl.blogspot.com/2013/06/tutorial-simple-start-with-opencl-and-c.html
*/

#include "stdafx.h"
#include <iostream>
//This will eliminate all the errors about depricated functions
#define CL_USE_DEPRECATED_OPENCL_2_0_APIS
#include <CL/cl.hpp>
#include <malloc.h>
using namespace std;

int main()
{
	//get all platforms (drivers)
	vector<cl::Platform> all_platforms;
	cl::Platform::get(&all_platforms);
	if (all_platforms.size() == 0)
	{
		cout << " No platforms found. Check OpenCL installation!\n";
		exit(1);
	}
	cl::Platform default_platform = all_platforms[0];
	cout << "Using platform: " << default_platform.getInfo<CL_PLATFORM_NAME>() << "\n";

	//get default device of the default platform
	vector<cl::Device> all_devices;
	default_platform.getDevices(CL_DEVICE_TYPE_ALL, &all_devices);
	if (all_devices.size() == 0)
	{
		std::cout << " No devices found. Check OpenCL installation!\n";
		exit(1);
	}
	cl::Device default_device = all_devices[0];
	cout << "Using device: " << default_device.getInfo<CL_DEVICE_NAME>() << "\n";

	cl::Context context({ default_device });
	cl::Program::Sources sources;

	// kernel calculates for each element C=A*A
	string kernel_code =
		"   void kernel simple_square(global const int* A, global int* C){       "
		"       C[get_global_id(0)]=A[get_global_id(0)]*A[get_global_id(0)];  "
		"   }                                                                 ";
	sources.push_back({ kernel_code.c_str(), kernel_code.length() });

	cl::Program program(context, sources);
	if (program.build({ default_device }) != CL_SUCCESS){
		cout << " Error building: " << program.getBuildInfo<CL_PROGRAM_BUILD_LOG>(default_device) << "\n";
		exit(1);
	}
	
	// create buffers on the device
	cl::Buffer buffer_A(context, CL_MEM_READ_WRITE, sizeof(int)* 10);	 
	cl::Buffer buffer_C(context, CL_MEM_READ_WRITE, sizeof(int)* 10);

	int A[] = { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 };	 

	//create queue to which we will push commands for the device.
	cl::CommandQueue queue(context, default_device);

	//writes array A  to the device
	queue.enqueueWriteBuffer(buffer_A, CL_TRUE, 0, sizeof(int)* 10, A); 

	// to run the kernel
	cl::Kernel kernel_add = cl::Kernel(program, "simple_square");
	kernel_add.setArg(0, buffer_A);	 
	kernel_add.setArg(1	, buffer_C);
	queue.enqueueNDRangeKernel(kernel_add, cl::NullRange, cl::NDRange(10), cl::NullRange);
	queue.finish();

	int C[10];
	//read result C from the device to array C
	queue.enqueueReadBuffer(buffer_C, CL_TRUE, 0, sizeof(int)* 10, C);

	//Displaying the Input and Output arrays
	cout << "\nInput Array: \n";
	for (int i = 0; i<10; i++)
	{
		cout << A[i] << " ";
	}
	cout << "\n\nOutput Array: \n";
	for (int i = 0; i<10; i++)
	{
		cout << C[i] << " ";
	}

	return 0;
}