EasyGL Tutorial - Transparency and Animation

#include <iostream.h>
#include "easygl.h"

int x=0, int y=0, xdir=5, ydir=25;

void EasyRender()
{
   clearGraph();

   //Notice for transparency you draw the back objects befor the near ones
   //And inorder to be see through the Alpha(last) value must be less than 1.0
   print(185, 210, "Hello World!",1.0,1.0,1.0,1.0);
   color(0.0, 0.2, 0.5, 0.8);
   square(50, 50, 350, 350);
   square(200, 200, 500, 500, 0.0, 0.5, 1.0, 0.6);


   //When animating we don't need any loops because EasyRender is in a loop it
   //self. it's called about 60 times(frames) a second(given the Video Card)
   circle(x, y, 10);
   x+= xdir;             //Make the circle move!
   y+= ydir;

   //This will cause the circle to bounce off the edges of the screen!
   if(x > 1004)          //Screen width - 20(r*2)
      xdir = -25;
   else if(x < 20)
      xdir = 25;
   if(y > 748)          //Screen height - 20
      ydir = -25;
   else if(y < 20)
      ydir = 25;

update();
}

int main()
{
   initEasyGL();
   return 1;
}