13. animation.cpp

#include<iostream>
#include<math.h>
#include<time.h>
#include<GL/glut.h>

 using namespace std;
 
 
   int x=0;
   int flag =0;
   
   void init()
   {
      glClearColor(1.0 ,1.0 ,1.0 ,0.0);
      glMatrixMode(GL_PROJECTION);
      gluOrtho2D(0, 640 , 0 ,480);
   }
   
    void object1()
    {
      glClear(GL_COLOR_BUFFER_BIT);
      glColor3f(1 , 0 ,0);
      glBegin(GL_POLYGON);
      glVertex2i(x , 220);
      glVertex2i(x+40 , 220);
      glVertex2i(x+40, 260);
      glVertex2i(x , 260);
      glEnd();
      glutSwapBuffers();
      
    }
    
    void timer(int)
    {
      glutPostRedisplay();
      glutTimerFunc(1000/60 , timer , 0);
      
      if(flag==0)
      {
        x = x+3;
      }
      if(flag==1)
      {
        x = x-3;
      }
      if(x == 600)
      {
        flag = 1;
      }
      if(x == 0)
      {
        flag =0;
      }
    }
    
     int main(int argc , char **argv)
     {
       glutInit(&argc , argv);
       glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB);
       glutInitWindowSize(640 , 480);
       glutInitWindowPosition(200 , 200);
       glutCreateWindow("Animation");
       
       init();
       
       glutDisplayFunc(object1);
       glutTimerFunc(1000 , timer , 0);
       glutMainLoop();
       
       return 0;
     }