//public void Intersects(ref BoundingBox box, out float? result)
//{
// result = Intersects(box);
//}
//public float? Intersects(BoundingFrustum frustum)
//{
// throw new NotImplementedException();
//}
//public float? Intersects(BoundingSphere sphere)
//{
// float? result;
// Intersects(ref sphere, out result);
// return result;
//}
//public float? Intersects(Plane plane)
//{
// throw new NotImplementedException();
//}
//public void Intersects(ref Plane plane, out float? result)
//{
// throw new NotImplementedException();
//}
public static float?Intersects(this Ray ray, BoundingSphere sphere)
{
// Find the vector between where the ray starts the the sphere's centre
Vector3 difference = sphere.Center - ray.origin;
float differenceLengthSquared = difference.sqrMagnitude;
float sphereRadiusSquared = sphere.Radius * sphere.Radius;
float distanceAlongRay;
// If the distance between the ray start and the sphere's centre is less than
// the radius of the sphere, it means we've intersected. N.B. checking the LengthSquared is faster.
if (differenceLengthSquared < sphereRadiusSquared)
{
return(0.0f);
}
//Vector3Helper.Dot(ref this.Direction, ref difference, out distanceAlongRay);
distanceAlongRay = Vector3Helper.Dot(ray.direction, difference);
// If the ray is pointing away from the sphere then we don't ever intersect
if (distanceAlongRay < 0)
{
return(null);
}
// Next we kinda use Pythagoras to check if we are within the bounds of the sphere
// if x = radius of sphere
// if y = distance between ray position and sphere centre
// if z = the distance we've travelled along the ray
// if x^2 + z^2 - y^2 < 0, we do not intersect
float dist = sphereRadiusSquared + distanceAlongRay * distanceAlongRay - differenceLengthSquared;
return((dist < 0) ? null : distanceAlongRay - (float?)Math.Sqrt(dist));
}
public BoundingSphere Transform(Matrix matrix)
{
BoundingSphere sphere = new BoundingSphere();
sphere.Center = Vector3Helper.Transform(ref this.Center, matrix);
sphere.Radius = this.Radius * ((float)Math.Sqrt((double)Math.Max(((matrix.M11 * matrix.M11) + (matrix.M12 * matrix.M12)) + (matrix.M13 * matrix.M13), Math.Max(((matrix.M21 * matrix.M21) + (matrix.M22 * matrix.M22)) + (matrix.M23 * matrix.M23), ((matrix.M31 * matrix.M31) + (matrix.M32 * matrix.M32)) + (matrix.M33 * matrix.M33)))));
return(sphere);
}
public void Transform(ref Matrix matrix, out BoundingSphere result)
{
result.Center = Vector3Helper.Transform(ref this.Center, matrix);
result.Radius = this.Radius * ((float)Math.Sqrt((double)Math.Max(((matrix.M11 * matrix.M11) + (matrix.M12 * matrix.M12)) + (matrix.M13 * matrix.M13), Math.Max(((matrix.M21 * matrix.M21) + (matrix.M22 * matrix.M22)) + (matrix.M23 * matrix.M23), ((matrix.M31 * matrix.M31) + (matrix.M32 * matrix.M32)) + (matrix.M33 * matrix.M33)))));
}
