void mouse(int button, int state, int x, int y)
{
    if (button == GLUT_RIGHT_BUTTON)
    {
if (state == GLUT_DOWN)
     cout << "Right button pressed"
     << endl;
else
     cout << "Right button lifted "
     << "at (" << x << "," << y
     << ")" << endl;
    }
}

glutMouseFunc(mouse);

glViewport(.......); // ماهي القيم الموجودة هنا

glOrtho(...........);// ماهي القيم الموجودة هنا

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


const float PI = 3.14159;

void init (void)
{
glClearColor (1.0, 1.0, 1.0, 0.0);
glMatrixMode (GL_PROJECTION);
gluOrtho2D (0.0, 400.0, 0.0, 300.0);
}
void displayiFcn (void)
{
glClear (GL_COLOR_BUFFER_BIT); // Clear display window.

glColor3f (1.0, 0.0, 0.0);

float theta;
float x , y;

glBegin (GL_POLYGON); // For a solid circle


for (theta = 0; theta < (2 * PI); theta += 2 * PI / 10000)
{
x = 200 + 50 * cos(theta);
y = 150 + 50 * sin(theta);
glVertex2f (x,y);
}
glEnd ( );
glFlush ( );
}

void displayFcn (void)
{
glClear (GL_COLOR_BUFFER_BIT); // Clear display window.

glColor3f (1.0, 0.0, 0.0);

float theta;
float x , y;

for (int i = 240; i >= 50; i--)
{

glBegin (GL_POLYGON);

for (theta = 0; theta < (2 * PI); theta += 2 * PI / 10000)
{
glVertex2f (x,y);
y = i + 50 * cos(theta);
x =i + 50 * sin(theta);

}

glEnd ( );
glFlush ( );
glClear (GL_COLOR_BUFFER_BIT); // Clear display window.
}


}
void mouse(int button, int state, int x, int y)
{

switch (button) {
case GLUT_LEFT_BUTTON:
if (state == GLUT_DOWN)

glutIdleFunc (displayFcn);
break;

case GLUT_RIGHT_BUTTON:
if (state == GLUT_DOWN)
//glutIdleFunc(NULL);
break;
default:
break;
}
}

int main (int argc, char** argv)
{
glutInit (&argc, argv);
glutInitDisplayMode (GLUT_SINGLE | GLUT_RGB);
glutInitWindowPosition (100, 100);
glutInitWindowSize (400, 300);
glutCreateWindow ("Moving Circle");

init ( );
glutDisplayFunc (displayiFcn);

glutMouseFunc(mouse);

glutMainLoop ( );
return 0;
}