// Intersection between 2 planes
public bool Intersect( Plane _p, Ray _ray )
{
// Check if both planes are coplanar
if ( (float) System.Math.Abs( 1.0f - _p.n.Dot(n) ) < float.Epsilon )
return false;
// Let's have fun!
float3 I = new float3();
_ray.Pos.Set( 0, 0, 0 );
_ray.Aim = n;
if ( !_p.Intersect( _ray, ref I ) )
return false;
_ray.Aim = _p.n;
if ( !_p.Intersect( _ray, ref I ) )
return false;
_ray.Pos = I;
_ray.Aim = I - _ray.Pos;
if ( !Intersect( _ray, ref I ) )
return false;
_ray.Pos = I;
// We have at least one point belonging to both planes!
_ray.Aim = n.Cross(_p.n).Normalized;
return true;
}
// Arithmetic operators
public static Plane operator *( Plane _Op0, float4x4 _Op1 )
{
Plane Ret = new Plane();
float3 n2 = (float3) (new float4( _Op0.n, 0 ) * _Op1);
Ret.d = -((float3) (new float4( -_Op0.d * _Op0.n, 0.0f ) * _Op1)).Dot( n2 );
Ret.n = n2;
return Ret;
}
// Intersection between 3 planes
public bool Intersect( Plane _p0, Plane _p1, ref float3 _intersection )
{
// Compute the intersection of 2 planes first, yielding a ray
Ray Hit = new Ray();
if ( !_p0.Intersect( _p1, Hit ) )
return false;
// Then compute the intersection of this ray with our plane
return Intersect( Hit, ref _intersection );
}
