public static Vector2f ClosestPointOnCircle(Circle2f circle, Vector2f p)
{
float cpx = p.x - circle.Center.x;
float cpy = p.y - circle.Center.y;
float dist = (float)Math.Sqrt(cpx * cpx + cpy * cpy);
return(new Vector2f(circle.Center.x + circle.Radius * dist, circle.Center.y + circle.Radius * dist));
}
public static bool CirlceContainsPoint(Circle2f circle, Vector2f p)
{
float cpx = p.x - circle.Center.x;
float cpy = p.y - circle.Center.y;
float r2 = circle.Radius * circle.Radius;
return((cpx * cpx + cpy * cpy) <= r2);
}
public static bool BoxIntersectsCircle(Box2f box, Circle2f circle)
{
if (circle.Center.x - circle.Radius > box.Max.x ||
circle.Center.x + circle.Radius < box.Min.x)
{
return(false);
}
if (circle.Center.y - circle.Radius > box.Max.y ||
circle.Center.y + circle.Radius < box.Min.y)
{
return(false);
}
return(true);
}
public bool Add(Vector2f position, float radius)
{
if (position.x < 0 || position.x > Width)
{
return(false);
}
if (position.y < 0 || position.y > Height)
{
return(false);
}
int x = (int)Math.Floor(position.x / CellSize);
int y = (int)Math.Floor(position.y / CellSize);
if (x < 0 || x >= GridWidth)
{
return(false);
}
if (y < 0 || y >= GridHeight)
{
return(false);
}
Circle2f circle = new Circle2f();
circle.Center = position;
circle.Radius = radius;
if (m_grid[x, y] == null)
{
m_grid[x, y] = new List <Circle2f>();
}
var list = m_grid[x, y];
list.Add(circle);
Count++;
return(true);
}
public static bool CircleIntersectsCircle(Circle2f circle0, Circle2f circle1)
{
float r = circle0.Radius + circle1.Radius;
return((circle0.Center - circle1.Center).SqrMagnitude <= r * r);
}
