/// <summary>
/// 交运算
/// </summary>
/// <param name="a"></param>
/// <param name="b"></param>
/// <returns></returns>
public static Bounds3 Intersect(Bounds3 a, Bounds3 b)
{
return(new Bounds3(
new Vector3f(Math.Max(a.pMin.X, b.pMin.X), Math.Max(a.pMin.Y, b.pMin.Y), Math.Max(a.pMin.Z, b.pMin.Z)),
new Vector3f(Math.Min(a.pMax.X, b.pMax.X), Math.Min(a.pMax.Y, b.pMax.Y), Math.Min(a.pMax.Z, b.pMax.Z))
));
}
/// <summary>
/// 并运算
/// </summary>
/// <param name="a"></param>
/// <param name="b"></param>
/// <returns></returns>
public static Bounds3 Union(Bounds3 a, Vector3f b)
{
Bounds3 ret = new Bounds3();
ret.pMin = Vector3f.Min(a.pMin, b);
ret.pMax = Vector3f.Max(a.pMax, b);
return(ret);
}
public static BVH Build <T>(Span <T> objs) where T : RenderObject
{
Bounds3 boundbox = objs[0].BoundBox;
foreach (var item in objs)
{
boundbox = Bounds3.Union(boundbox, item.BoundBox);
}
BVH re = new BVH()
{
BoundBox = boundbox
};
if (objs.Length < 5)
{
re.Childs = objs.ToArray();
goto RTPoint;
//return re;
}
int divideWay = 0;
{
Vector3f v = boundbox.pMax - boundbox.pMin;
if (v.X < v.Y)
{
if (v.Y < v.Z)
{
divideWay = 2;
}
else
{
divideWay = 1;
}
}
else
{
if (v.X < v.Z)
{
divideWay = 2;
}
else
{
divideWay = 0;
}
}
}
int dividePoint = -1;
if (divideWay == 0)
{
dividePoint = QuickCoordationX(objs);
}
else if (divideWay == 1)
{
dividePoint = QuickCoordationY(objs);
}
else
{
dividePoint = QuickCoordationZ(objs);
}
BVH l = Build(objs.Slice(0, dividePoint));
BVH r = Build(objs.Slice(dividePoint));
re.Childs = new IRayCastAble[] { l, r };
RTPoint:
return(re);
}