//degree
var degree:Number = 0;
//acceleration
var ax:Number;
var ay:Number;
//time step
var dt:Number = .00001;
//initial position
var yo:Number=(red.y-blue.y);
var xo:Number=(blue.x-red.x);
//current position
var xi:Number = 0;
var yi:Number = 0;
//initial velocity
var vxo:Number = 0;
var vyo:Number = -1;
//current velocity
var vxi:Number = 0;
var vyi:Number = 0;
//trig a
var a:Number = 0;
//trig b
var b:Number = 0;
//radius (hypotenous)
var r:Number = 0;
//mass
var bluemass:Number = 1000;
var redmass:Number = 100000000;
//radian of angle
var radian:Number = 0;
//gravity
var g:Number = 0;
var grav:Number = Math.pow(1,-8);
//blue pos
var xpos:Number = blue.x;
var ypos:Number = blue.y;
//red pos
var xpossave:Number=red.x;
var ypossave:Number=red.y;
//rk4
var kx1:Number = 0;
var kvx1:Number = 0;
var kx2:Number = 0;
var kvx2:Number = 0;
var kx3:Number = 0;
var kvx3:Number = 0;
var kx4:Number = 0;
var kvx4:Number = 0;
var ky1:Number = 0;
var kvy1:Number = 0;
var ky2:Number = 0;
var kvy2:Number = 0;
var ky3:Number = 0;
var kvy3:Number = 0;
var ky4:Number = 0;
var kvy4:Number = 0;
addEventListener(Event.ENTER_FRAME,world); function world(e:Event):void {
a = ypos-ypossave;
b = xpossave-xpos;

if (b >= 0 && a >= 0)
{
    kx1 = vxo;
    ky1 = vyo;
    r = Math.sqrt(Math.pow(a,2) + Math.pow(b,2));
    radian=(Math.asin(a/r));
    g=(grav)*(bluemass*redmass)/(Math.pow(r,2));;
    kvx1=-((g)*Math.cos(radian))/bluemass;
    kvy1=((g)*Math.sin(radian))/bluemass;

    kx2=vxo+(kvx1*(dt/2));
    ky2=vyo+(kvy1*(dt/2));
    a = (a+ky2);
    b = (b+kx2);
    r = Math.sqrt(Math.pow(a,2) + Math.pow(b,2));
    radian=(Math.asin(a/r));
    g=(grav)*(bluemass*redmass)/(Math.pow(r,2));
    kvx2=-((g)*Math.cos(radian))/bluemass;
    kvy2=((g)*Math.sin(radian))/bluemass;


    kx3=vxo+(kvx2*(dt/2));
    ky3=vyo+(kvy2*(dt/2));
    a = (a+ky3);
    b = (b+kx3);
    r = Math.sqrt(Math.pow(a,2) + Math.pow(b,2));
    radian=(Math.asin(a/r));
    g=(grav)*(bluemass*redmass)/(Math.pow(r,2));
    kvx3=-((g)*Math.cos(radian))/bluemass;
    kvy3=((g)*Math.sin(radian))/bluemass;


    kx4=vxo+(kvx3*(dt));
    ky4=vyo+(kvy3*(dt));
    a = (a+ky4);
    b = (b+kx4);
    r = Math.sqrt(Math.pow(a,2) + Math.pow(b,2));
    radian=(Math.asin(a/r));
    g=(grav)*(bluemass*redmass)/(Math.pow(r,2));
    kvx4=-((g)*Math.cos(radian))/bluemass;
    kvy4=((g)*Math.sin(radian))/bluemass;

}
xi=xo+(dt/6)*(kx1+2*(kx2)+2*(kx3)+kx4);
vxi=vxo+(dt/6)*(kvx1+2*(kvx2)+2*(kvx3)+kvx4);
yi=yo+(dt/6)*(ky1+2*(ky2)+2*(ky3)+ky4);
vyi=vyo+(dt/6)*(kvy1+2*(kvy2)+2*(kvy3)+kvy4);
vxo = vxi;
vyo = vyi;
xpos = xi;
ypos = yi;
yo=(yi);
xo=(xi);
}
addEventListener(Event.ENTER_FRAME,drawing); function drawing(e:Event):void {
blue.x = xpos+xpossave;
blue.y = ypossave-ypos;
}