public void Update(Vector2 location)
{
if (performCalled)
{
return;
}
if (!firstSet)
{
firstLocation = location;
firstSet = true;
}
var dot = Vector2.Dot(firstLocation.Normalize(), location.Normalize());
var angle = JryMath.Acos(dot);
var a = (updated - center).Normalize();
var b = (location - center).Normalize();
angle = (float)(Math.Atan2(a.Y, a.X) -
Math.Atan2(b.Y, b.X));
if (!float.IsNaN(angle))
{
updatablePolygon.RotateSelected(angle, center);
}
updated = location;
}
private float decideAngle(float x, float y)
{
if (x >= 0 && y >= 0)
{
return(JryMath.Acos(x));
}
else if (x >= 0)
{
return(JryMath.Pi * 2 - JryMath.Acos(x));
}
else if (y >= 0)
{
return(JryMath.Acos(x));
}
else
{
return(JryMath.Pi * 2 - JryMath.Acos(x));
}
}
