public Vector2 Project(Vector2 axis)
{
if (!_axes.Contains(axis))
_axes.Add(axis);
float a = axis.Y / axis.X;
float min = Vector2.Dot(new Vector2(GetCenter().X - (float)(Radius * Math.Sin(a)), GetCenter().Y - (float)(Radius * Math.Cos(a))), axis);
float max = Vector2.Dot(new Vector2(GetCenter().X + (float)(Radius * Math.Sin(a)), GetCenter().Y + (float)(Radius * Math.Cos(a))), axis);
return new Vector2(min, max);
}
private bool Intersects(CollisionCircle element)
{
ComputeCircleAxes(element);
// loop over the axes of this polygon
for (int i = 0; i < _axes.Count; i++)
{
Vector2 axis = _axes[i];
// project both shapes onto the axis
Vector2 p1 = this.Project(axis);
Vector2 p2 = element.Project(axis);
// do the projections overlap?
if (!Overlap(p1, p2))
{
// then we can guarantee that the shapes do not overlap
return(false);
}
}
// if we get here then we know that every axis had overlap on it
// so we can guarantee an intersection
return(true);
}