It'd be better to define how many vertices for the loop.
PHP Code:
temp.vertices = 32;
temp.radius = 3;
temp.circle = new[0];
temp.O = {player.x + 1.5,player.y + 2};
for (temp.i=0;temp.i<temp.vertices;temp.i++) {
temp.a = (pi*2)*temp.i;
temp.circle.add(temp.O[0] + cos(temp.a)*temp.radius);
temp.circle.add(temp.O[1] - sin(temp.a)*temp.radius);
}
showpoly(200,temp.circle);
At least, that's my opinion. I find it easier to read.