This code defines functions to initialize and display a checkerboard pattern using OpenGL. The init() function sets the display window properties and projection. The CheckerBoard() function uses nested for loops to draw 64 colored squares arranged in an 8x8 checkerboard pattern by alternating orange and brown colors. It draws each square as a quad using GL_QUADS. The Display() function clears the display and calls CheckerBoard() before flushing the buffer. The main() function initializes GLUT and creates a window, then registers the display callback and enters the main loop.

1. #include <gl//glut.h>
//#include<math.h>
void init ()
{
glClearColor(0.0, 0.0, 0.0, 0.0);
glPointSize(5.0);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
//setting the resolution for the 2D object
gluOrtho2D(0.0,300.0, 0.0, 300.0); //void gluOrtho2D(left,r,bot,top);
//gluOrtho2D sets up a two-dimensional orthographic viewing region.
//equivalent to calling glOrtho with near = -1 and far = 1 .
//void glOrtho(left,right,bottom,top,nearVal,farVal);
}
void CheckerBoard()
{
glPointSize(5.0);
//
int x1,y1;
x1=0;
y1=500;
for(int i=1;i<=8;i++)
{
x1=x1+50;
y1=500;
for(int j=1;j<=8;j++)
{
y1=y1-50;
glBegin(GL_QUADS);
if(i%2 != 0 )
{
if( j%2 != 0 )
{
//glColor3f(1.0,1.0,1.0); //white
glColor3f(202.0/255.00, 169.0/255.0,
106.0/255.0);//orange
glVertex3f(x1,y1,0);
glVertex3f(x1+50,y1,0);
glVertex3f(x1+50,y1-50,0);
glVertex3f(x1,y1-50,0);
}
else
{
glColor3f(146.0/255.0, 140.0/255.0,
168.0/255.0);//brown
//glColor3f(0.0,0.0,0.0); //black
glVertex3f(x1,y1,0);
glVertex3f(x1+50,y1,0);
glVertex3f(x1+50,y1-50,0);
glVertex3f(x1,y1-50,0);
}
}

2. else{
if(j%2 != 0)
{
glColor3f(146.0/255.0, 140.0/255.0,
168.0/255.0);
//glColor3f(0.0,0.0,0.0);
glVertex3f(x1,y1,0);
glVertex3f(x1+50,y1,0);
glVertex3f(x1+50,y1-50,0);
glVertex3f(x1,y1-50,0);
}
else{
glColor3f(202.0/255.00, 169.0/255.0,
106.0/255.0);
// glColor3f(1.0,1.0,1.0);
glVertex3f(x1,y1,0);
glVertex3f(x1+50,y1,0);
glVertex3f(x1+50,y1-50,0);
glVertex3f(x1,y1-50,0);
}
}
glEnd();
}
}
}
void Display()
{
glClear(GL_COLOR_BUFFER_BIT);
//calling
CheckerBoard();
glFlush ();
}
int main(int argc, char** argv)
{
glutInit(&argc, argv);
glutInitDisplayMode (GLUT_SINGLE | GLUT_RGB);
glutInitWindowSize (900, 450);
glutInitWindowPosition (100, 100);
glutCreateWindow ("Assignment: Lab 2");
init ();
glutDisplayFunc(Display);
glutMainLoop();
}