#include <stdio.h>
#include "tbb/tick_count.h"
#include "tbb/blocked_range2d.h"
#include "tbb/parallel_for.h"

#define IMAGE_FILEPATH "C:\\Users\\Ap0\\Desktop\\image\\image.bmp"

/*
Go to "Project -> Properties -> Configuration Properties -> Intel Performance Libraries -> Use Intel TBB" set to "Yes"
Go to "Tools -> Options -> Debugging -> Symbols" select checkbox "Microsoft Symbol Servers"
Go to "Project -> Properties -> Configuration Properties -> C/C++ -> Preprocessor -> Preprocessor Definitions" add "_CRT_SECURE_NO_WARNINGS"
*/

/*
matrix R [M][N] = matrix A [M][P]  *  matrix B [P][N]
*/

unsigned char* readBMP()
{
	int i;
	FILE* f = fopen(IMAGE_FILEPATH, "rb");
	unsigned char info[54];
	fread(info, sizeof(unsigned char), 54, f); // read the 54-byte header

	// extract image height and width from header
	int width = *(int*)&info[18];
	int height = *(int*)&info[22];

	int size = 3 * width * height;
	unsigned char* data = new unsigned char[size]; // allocate 3 bytes per pixel
	fread(data, sizeof(unsigned char), size, f); // read the rest of the data at once
	fclose(f);
	unsigned char* dataGrayScale = new unsigned char[width*height];
	int counter = 0;

	for (i = 0; i < size; i += 3)
	{
		dataGrayScale[i] = (data[i] + data[i + 1] + data[i + 2]) / 3; //the avg of the rgb is the grayscale value
			counter++;
	}

	delete[] data;
	return dataGrayScale;
}

void rgb_to_grayscale_serial()
{
	readBMP();
}

void rgb_to_grayscale_parallel()
{

}

int main()
{
	/* serial converting of RGB image to grayscale */
	printf("Serial converting of RGB image to grayscale...\n");
	getchar();
	tbb::tick_count startTime = tbb::tick_count::now();
	rgb_to_grayscale_serial();
	tbb::tick_count endTime = tbb::tick_count::now();
	printf("Time: %lf seconds\n", (endTime - startTime).seconds());

	/* parallel converting of RGB image to grayscale */
	printf("Parallel converting of RGB image to grayscale...\n");
	getchar();
	startTime = tbb::tick_count::now();
	rgb_to_grayscale_parallel();
	endTime = tbb::tick_count::now();
	printf("Time: %lf seconds\n", (endTime - startTime).seconds());

	getchar();

	return 0;
}