private CollisionDetails GetFirstCollisionInternal(Shapes.Ray ray, bool isRayInside, bool useBiggerX, bool useBiggerY, bool useBiggerZ)
{
var result = new CollisionDetails {
Distance = double.PositiveInfinity
};
if (isRayInside) // recheck because ray was inside parent
{
isRayInside = PointCube.Encloses(_center, _halfWidth, ray.Origin);
}
// not inside and no hit -> return
if (!isRayInside && double.IsInfinity(RayIntersectionDistance(ray, useBiggerX, useBiggerY, useBiggerZ)))
{
return(result);
}
if (_children != null && _children.Length > 0)
{
foreach (var child in _children)
{
var collision = child.GetFirstCollisionInternal(ray, isRayInside, useBiggerX, useBiggerY, useBiggerZ);
if (!double.IsInfinity(collision.Distance))
{
result = collision;
break;
}
}
}
foreach (var o3D in _objects)
{
double distance = o3D.GetHitPointDistance(ray);
if (distance > 0 && distance < result.Distance)
{
result.Obj = o3D;
result.Distance = distance;
}
}
return(result);
}
/// <summary>
/// Get the nearest intersection with the cube
/// </summary>
/// <param name="ray"></param>
/// <param name="useBiggerX"></param>
/// <param name="useBiggerY"></param>
/// <param name="useBiggerZ"></param>
/// <returns></returns>
private double RayIntersectionDistance(Shapes.Ray ray, bool useBiggerX, bool useBiggerY, bool useBiggerZ)
{
if (PointCube.Encloses(_center, _halfWidth, ray.Origin))
{
return(0);
}
var normal = new Vect3 {
X = useBiggerX ? _halfWidth : -_halfWidth
};
var planeCenter = _center + normal;
double distance = SideRayIntersectionDistance(ray, normal, planeCenter);
// we can return instantly as we only evaluate the hear side -> only one side should be hit at any time
if (!double.IsInfinity(distance))
{
return(distance);
}
normal = new Vect3 {
Y = useBiggerY ? _halfWidth : -_halfWidth
};
planeCenter = _center + normal;
distance = SideRayIntersectionDistance(ray, normal, planeCenter);
if (!double.IsInfinity(distance))
{
return(distance);
}
normal = new Vect3 {
Z = useBiggerZ ? _halfWidth : -_halfWidth
};
planeCenter = _center + normal;
distance = SideRayIntersectionDistance(ray, normal, planeCenter);
if (!double.IsInfinity(distance))
{
return(distance);
}
return(double.PositiveInfinity);
}
/**
* @param v a <code>Vect3</code> representing a point
* @return true if, and only if, <code>v</code> is enclosed by this subtree.
*/
public bool Encloses(Vect3 v)
{
return(PointCube.Encloses(Center, Width / 2 + Constants.EPS, v));
}