public static void addPoint(Polygon poly, float x, float y, int index) {
float verts[] = poly.getVertices();
x -= poly.getX();
y -= poly.getY();
int length = verts.length;
float destination[] = new float[length + 2];
System.arraycopy(verts, 0, destination, 0, index);
destination[index] = x;
destination[index + 1] = y;
System.arraycopy(verts, index, destination, index + 2, length - index);
poly.setVertices(destination);
}
