/// <summary> Intersect the <see cref="AxisAlignedBox"/> by a <paramref name="ray"/>.
/// Using Amy Williams's "An Efficient and Robust Ray–Box Intersection" Algorithm </summary>
/// <param name="ray">The <see cref="Ray"/> to intersect the <see cref="IAxisAlignedBox"/> with</param>
/// <returns>Whether and when the <see cref="Ray"/> intersects the <see cref="IAxisAlignedBox"/></returns>
public IEnumerable <Position1> IntersectDistances(IRay ray)
{
Position1 tmin = (Bounds[ray.Sign.X].X - ray.Origin.X) * ray.InvDirection.X;
Position1 tmax = (Bounds[1 - ray.Sign.X].X - ray.Origin.X) * ray.InvDirection.X;
Position1 tymin = (Bounds[ray.Sign.Y].Y - ray.Origin.Y) * ray.InvDirection.Y;
Position1 tymax = (Bounds[1 - ray.Sign.Y].Y - ray.Origin.Y) * ray.InvDirection.Y;
if ((tmin > tymax) || (tmax < tymin))
{
yield break;
}
tmin = Position1.Max(tmin, tymin);
tmax = Position1.Min(tmax, tymax);
Position1 tzmin = (Bounds[ray.Sign.Z].Z - ray.Origin.Z) * ray.InvDirection.Z;
Position1 tzmax = (Bounds[1 - ray.Sign.Z].Z - ray.Origin.Z) * ray.InvDirection.Z;
if ((tmin > tzmax) || (tmax < tzmin))
{
yield break;
}
yield return(Position1.Max(tmin, tzmin));
yield return(Position1.Min(tmax, tzmax));
}
/// <summary> Clip the <see cref="AxisAlignedBox"/> by a <paramref name="plane"/> </summary>
/// <param name="plane">The <see cref="AxisAlignedPlane"/> to clip the <see cref="AxisAlignedBox"/> with</param>
/// <returns>A new clipped <see cref="AxisAlignedBox"/> if it's not clipped entirely</returns>
public IEnumerable <AxisAlignedBox> Clip(AxisAlignedPlane plane)
{
Position3 minCorner = MinCorner;
Position3 maxCorner = MaxCorner;
if (plane.Normal == Normal3.UnitX)
{
minCorner = new(Position1.Max(MinCorner.X, plane.Position.X), MinCorner.Y, MinCorner.Z);
}
else if (plane.Normal == -Normal3.UnitX)
{
maxCorner = new(Position1.Min(MinCorner.X, plane.Position.X), MaxCorner.Y, MaxCorner.Z);
}
else if (plane.Normal == Normal3.UnitY)
{
minCorner = new(MinCorner.X, Position1.Max(MinCorner.Y, plane.Position.Y), MinCorner.Z);
}
else if (plane.Normal == -Normal3.UnitY)
{
maxCorner = new(MaxCorner.X, Position1.Min(MaxCorner.Y, plane.Position.Y), MaxCorner.Z);
}
else if (plane.Normal == Normal3.UnitZ)
{
minCorner = new(MinCorner.X, MinCorner.Y, Position1.Max(MinCorner.Z, plane.Position.Z));
}
else if (plane.Normal == -Normal3.UnitZ)
{
maxCorner = new(MaxCorner.X, MaxCorner.Y, Position1.Min(MaxCorner.Z, plane.Position.Z));
}
if (minCorner == MinCorner && maxCorner == MaxCorner)
{
yield return(this);
}
else if (minCorner.X < maxCorner.X && minCorner.Y < maxCorner.Y && minCorner.Z < maxCorner.Z)
{
yield return(new AxisAlignedBox(minCorner, maxCorner));
}
}
