protected override Vector2 CalculateMinimumSize()
{
var separation = ActualSeparation;
var minWidth = 0f;
var minHeight = 0f;
var first = true;
foreach (var child in Children)
{
if (!child.Visible)
{
continue;
}
var(childWidth, childHeight) = child.CombinedMinimumSize;
if (Vertical)
{
minHeight += childHeight;
if (!first)
{
minHeight += separation;
}
first = false;
minWidth = MathF.Max(minWidth, childWidth);
}
else
{
minWidth += childWidth;
if (!first)
{
minWidth += separation;
}
first = false;
minHeight = MathF.Max(minHeight, childHeight);
}
}
return(new Vector2(minWidth, minHeight));
}
public static float Median(float a, float b, float c)
{
return(MathF.Max(MathF.Min(a, b), MathF.Min(MathF.Max(a, b), c)));
}
public static float Max(float a, float b, float c, float d)
{
return(MathF.Max(a, MathF.Max(b, MathF.Max(c, d))));
}
public bool Intersects(Box2 box, out float distance, out Vector2 hitPos)
{
hitPos = Vector2.Zero;
distance = 0;
var tmin = 0.0f; // set to -FLT_MAX to get first hit on line
var tmax = float.MaxValue; // set to max distance ray can travel (for segment)
const float epsilon = 1.0E-07f;
// X axis slab
{
if (MathF.Abs(_direction.X) < epsilon)
{
// ray is parallel to this slab, it will never hit unless ray is inside box
if (_position.X < MathF.Min(box.Left, box.Right) || _position.X > MathF.Max(box.Left, box.Right))
{
return(false);
}
}
// calculate intersection t value of ray with near and far plane of slab
var ood = 1.0f / _direction.X;
var t1 = (MathF.Min(box.Left, box.Right) - _position.X) * ood;
var t2 = (MathF.Max(box.Left, box.Right) - _position.X) * ood;
// Make t1 be the intersection with near plane, t2 with far plane
if (t1 > t2)
{
MathHelper.Swap(ref t1, ref t2);
}
// Compute the intersection of slab intersection intervals
tmin = MathF.Max(t1, tmin);
tmax = MathF.Min(t2, tmax); // Is this Min (SE) or Max(Textbook)
// Exit with no collision as soon as slab intersection becomes empty
if (tmin > tmax)
{
return(false);
}
}
// Y axis slab
{
if (MathF.Abs(_direction.Y) < epsilon)
{
// ray is parallel to this slab, it will never hit unless ray is inside box
if (_position.Y < MathF.Min(box.Top, box.Bottom) || _position.Y > MathF.Max(box.Top, box.Bottom))
{
return(false);
}
}
// calculate intersection t value of ray with near and far plane of slab
var ood = 1.0f / _direction.Y;
var t1 = (MathF.Min(box.Top, box.Bottom) - _position.Y) * ood;
var t2 = (MathF.Max(box.Top, box.Bottom) - _position.Y) * ood;
// Make t1 be the intersection with near plane, t2 with far plane
if (t1 > t2)
{
MathHelper.Swap(ref t1, ref t2);
}
// Compute the intersection of slab intersection intervals
tmin = MathF.Max(t1, tmin);
tmax = MathF.Min(t2, tmax); // Is this Min (SE) or Max(Textbook)
// Exit with no collision as soon as slab intersection becomes empty
if (tmin > tmax)
{
return(false);
}
}
// Ray intersects all slabs. Return point and intersection t value
hitPos = _position + _direction * tmin;
distance = tmin;
return(true);
}
