#include <iostream>
#include <stdio.h>
#include <math.h>
#include <thread>

#define thread_count 8

using namespace std;

const int iXmax = 800;
const int iYmax = 800;

const double CxMin=-2.5;
const double CxMax=1.5;
const double CyMin=-2.0;
const double CyMax=2.0;

double PixelWidth=(CxMax-CxMin)/iXmax;
double PixelHeight=(CyMax-CyMin)/iYmax;

const int MaxColorComponentValue=255;

FILE * fp;
char const *filename="new1.ppm";
char const *comment="# ";

static unsigned char color[iXmax][iYmax][3];

const int IterationMax=200;

const double EscapeRadius=2;
double ER2=EscapeRadius*EscapeRadius;

void mandelBrotDraw(int min, int max, int i)
{
    double Cx, Cy, Zx, Zy, Zx2, Zy2;
    int iX, iY, Iteration;
    for(iY=0;iY<iYmax;iY++)
    {
        Cy=CyMin + iY*PixelHeight;
        if (fabs(Cy)< PixelHeight/2) Cy=0.0; /* Main antenna */
        for(iX=0;iX<iXmax;iX++)
        {
            Cx=CxMin + iX*PixelWidth;
            /* initial value of orbit = critical point Z= 0 */
            Zx=0.0;
            Zy=0.0;

            Zx2=Zx*Zx;
            Zy2=Zy*Zy;

            for (Iteration=0;Iteration<IterationMax && ((Zx2+Zy2)<ER2);Iteration++)
            {
                Zy=2*Zx*Zy + Cy;
                Zx=Zx2-Zy2 +Cx;
                Zx2=Zx*Zx;
                Zy2=Zy*Zy;
            }

            /* compute  pixel color (24 bit = 3 bytes) */
            if (Iteration==IterationMax)
            {
                color[iX][iY][0]=(i*255)/(thread_count - 1);
                color[iX][iY][1]=(i*255)/(thread_count - 1);
                color[iX][iY][2]=(i*255)/(thread_count - 1);
            }
            else
            {
                color[iX][iY][0]=255 - (i*255)/(thread_count - 1);  /* Red*/
                color[iX][iY][1]=255 - (i*255)/(thread_count - 1);  /* Green */
                color[iX][iY][2]=255 - (i*255)/(thread_count - 1);  /* Blue */
            };
        }
    }
}

int main()
{
    fp= fopen(filename,"wb"); /* b -  binary mode */
    fprintf(fp,"P6\n %s\n %d\n %d\n %d\n",comment,iXmax,iYmax,MaxColorComponentValue);

    thread magazynWatkow[thread_count];

    for(int i=0; i<thread_count; i++)
        magazynWatkow[i] = thread(mandelBrotDraw, i*(iYmax / thread_count), (i + 1)*(iYmax / thread_count), i);

    for(int i=0; i<thread_count; i++)
        magazynWatkow[i].join();

    for(int iY=0; iY<iYmax;iY++)
        for(int iX=0; iX<iXmax;iX++)
            fwrite(color[iX][iY],1,3,fp);

    fclose(fp);
    return 0;
}