OPENGL PROGRAM TO DRAW MOSAIC

#include<GL/glut.h>
#include<stdlib.h>
#include<time.h>

const int screenWidth=640;
const int screenHeight=480;


void myInit()
{
     glClearColor(1.0,1.0,1.0,0.0);
     glColor3f(1.0,0.0,0.0);
     glPointSize(3.0);
     glMatrixMode(GL_PROJECTION);
     glLoadIdentity();
     gluOrtho2D(0.0,(GLdouble)screenWidth,0.0,(GLdouble)screenHeight);

    
     }
    
     void myDisplay()
     {
          srand(time(NULL));
          GLint i=0;
          GLint x1=0,y1=0,x2=0,y2=0;
          GLfloat col=0;
          glClear(GL_COLOR_BUFFER_BIT);
          for(i=0;i<50;i++)
          {
                           x1=rand()%screenWidth;
                           y1=rand()%screenHeight;
                           x2=rand()%screenWidth;
                           y2=rand()%screenHeight;
                           col=(rand()%10)/10.0;
                           glColor3f(col/2,col,col);
                           glRecti(x1,y1,x2,y2);
                           }
                           glFlush();
          }
                            

    
     int main(int argc, char **argv)
     {
         glutInit(&argc,argv);
         glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB);
         glutInitWindowSize(screenWidth,screenHeight);
         glutCreateWindow("drawing rectangles");
         glutDisplayFunc(myDisplay);
      
         myInit();
        
         glutMainLoop();
         }