#include <iostream.h>
#include <conio.h>
#include <math.h>

//------------sourcea.ir----------------------------------//
#include<windows.h>       // for MS Windows
#include<gl\glut.h>       // GLUT, include glu.h and gl.h

//Note: GLglut.h path depending on the system in use
 
int color = 0;
GLint width = 800;
GLint hight = 600;
 
void init()
{
    // Set display window color to as glClearColor(R,G,B,Alpha)
    glClearColor(0, 1, 1, 0);
    // Set projection parameters.
    glMatrixMode(GL_PROJECTION);
    // Set 2D Transformation as gluOrtho2D(Min Width, Max Width, Min Height, Max Height)
    gluOrtho2D(0, width, 0, hight);
}
 
void drawSquare(GLint x1, GLint y1, GLint x2, GLint y2, GLint x3, GLint y3, GLint x4, GLint y4)
{
    // if color is 0 then draw white box and change value of color = 1
    if (color == 0)
    {
        glColor3f(1, 1, 1); // white color value is 1 1 1
        color = 1;
    }
    // if color is 1 then draw black box and change value of color = 0
    else
    {
        glColor3f(0, 0, 0); // black color value is 0 0 0
        color = 0;
    }
 
    // Draw Square
    glBegin(GL_POLYGON);
    glVertex2i(x1, y1);
    glVertex2i(x2, y2);
    glVertex2i(x3, y3);
    glVertex2i(x4, y4);
    glEnd();
}
void chessboard()
{
    glClear(GL_COLOR_BUFFER_BIT); // Clear display window
    GLint x, y;
    GLint squareWidthInPixel = 100;
    GLint squareHightInPixel = 75;
    for (x = 0; x <= width; x += squareWidthInPixel)
    {
        for (y = 0; y <= hight; y += squareHightInPixel)
        {
            drawSquare(x, y + squareHightInPixel, x + squareWidthInPixel, y + squareHightInPixel, x + squareWidthInPixel, y, x, y);
        }
    }
    // Process all OpenGL routine s as quickly as possible
    glFlush();
}
 
int main(int agrc, char ** argv)
{
    // Initialize GLUT
    glutInit(&agrc, argv);
    // Set display mode
    glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB);
    // Set top - left display window position.
    glutInitWindowPosition(100, 100);
    // Set display window width and height
    glutInitWindowSize(800, 600);
    // Create display window with the given title
    glutCreateWindow("Chess Board using OpenGL in C++");
    // Execute initialization procedure
    init();
    // Send graphics to display window
    glutDisplayFunc(chessboard);
    // Display everything and wait.
    glutMainLoop();
}