Programming and Graphics

7.7 Three-dimensional interactive graph 243

cout << " right-mouse button to rotate up-down" << endl;

cout << " both buttons to zoom" << endl;

}

//--- If ’q’ is pressed, quit:

if(kbd==’q’)

{

vexit();

return;

}

//--- Check the mouse:

click = slocator (&xaddr, &yaddr);

//--- Not pressed:

if(click==0)

{

goto again;

}

//--- Ignore if cursor lies outside the plotting window

if( xaddr<-1 || xaddr > 1||yaddr<-1 || yaddr > 1)

goto again;

//--- Rotate if left button is pressed:

if(click==1)

{

angx = angxinit+200.0*yaddr;

color(bgc);

clear();

drawplot3d();

}

//-- Rotate if right button is pressed:

if(click==4)

{

angy = angyinit+200.0*xaddr;

color(bgc);

clear();

drawplot3d();

}