public double?Intersects(BoundingBox box)
{
//first test if start in box
if (Position.X >= box.Min.X &&
Position.X <= box.Max.X &&
Position.Y >= box.Min.Y &&
Position.Y <= box.Max.Y &&
Position.Z >= box.Min.Z &&
Position.Z <= box.Max.Z)
{
return(0.0f); // here we concidere cube is full and origine is in cube so intersect at origine
}
//Second we check each face
Vector3 maxT = new Vector3(-1.0f);
//Vector3 minT = new Vector3(-1.0f);
//calcul intersection with each faces
if (Position.X < box.Min.X && Direction.X != 0.0f)
{
maxT.X = (box.Min.X - Position.X) / Direction.X;
}
else if (Position.X > box.Max.X && Direction.X != 0.0f)
{
maxT.X = (box.Max.X - Position.X) / Direction.X;
}
if (Position.Y < box.Min.Y && Direction.Y != 0.0f)
{
maxT.Y = (box.Min.Y - Position.Y) / Direction.Y;
}
else if (Position.Y > box.Max.Y && Direction.Y != 0.0f)
{
maxT.Y = (box.Max.Y - Position.Y) / Direction.Y;
}
if (Position.Z < box.Min.Z && Direction.Z != 0.0f)
{
maxT.Z = (box.Min.Z - Position.Z) / Direction.Z;
}
else if (Position.Z > box.Max.Z && Direction.Z != 0.0f)
{
maxT.Z = (box.Max.Z - Position.Z) / Direction.Z;
}
//get the maximum maxT
if (maxT.X > maxT.Y && maxT.X > maxT.Z)
{
if (maxT.X < 0.0f)
{
return(null); // ray go on opposite of face
}
//coordonate of hit point of face of cube
double coord = Position.Z + maxT.X * Direction.Z;
// if hit point coord ( intersect face with ray) is out of other plane coord it miss
if (coord < box.Min.Z || coord > box.Max.Z)
{
return(null);
}
coord = Position.Y + maxT.X * Direction.Y;
if (coord < box.Min.Y || coord > box.Max.Y)
{
return(null);
}
return(maxT.X);
}
if (maxT.Y > maxT.X && maxT.Y > maxT.Z)
{
if (maxT.Y < 0.0f)
{
return(null); // ray go on opposite of face
}
//coordonate of hit point of face of cube
double coord = Position.Z + maxT.Y * Direction.Z;
// if hit point coord ( intersect face with ray) is out of other plane coord it miss
if (coord < box.Min.Z || coord > box.Max.Z)
{
return(null);
}
coord = Position.X + maxT.Y * Direction.X;
if (coord < box.Min.X || coord > box.Max.X)
{
return(null);
}
return(maxT.Y);
}
else //Z
{
if (maxT.Z < 0.0f)
{
return(null); // ray go on opposite of face
}
//coordonate of hit point of face of cube
double coord = Position.X + maxT.Z * Direction.X;
// if hit point coord ( intersect face with ray) is out of other plane coord it miss
if (coord < box.Min.X || coord > box.Max.X)
{
return(null);
}
coord = Position.Y + maxT.Z * Direction.Y;
if (coord < box.Min.Y || coord > box.Max.Y)
{
return(null);
}
return(maxT.Z);
}
}
public void Intersects(ref BoundingBox box, out double?result)
{
result = Intersects(box);
}
