/// <summary>
/// Calculates the angle between this plane and another one.
/// </summary>
/// <param name="other">The other plane to calculate the angle with.</param>
public float AngleBetween(PlaneF other)
{
var numerator = System.Math.Abs((A * other.A) + (B * other.B) + (C * other.C));
var denominator = Normal.Length * other.Normal.Length;
var cosAlpha = numerator / denominator;
return((float)System.Math.Acos(cosAlpha));
}
/// <summary>
/// (Re)Calculates the frustum planes.
/// If feeded with a projection matrix, the frustum planes are in View Space.
/// If feeded with a view projection matrix, the frustum planes are in World Space.
/// If feeded with a model view projection matrix, the frustum planes are in Model Space.
/// See: http://www8.cs.umu.se/kurser/5DV051/HT12/lab/plane_extraction.pdf
/// </summary>
/// <param name="mat">The matrix from which to extract the planes.</param>
public void CalculateFrustumPlanes(float4x4 mat)
{
// left
var left = new PlaneF()
{
A = mat.M41 + mat.M11,
B = mat.M42 + mat.M12,
C = mat.M43 + mat.M13,
D = mat.M44 + mat.M14
};
// right
var right = new PlaneF()
{
A = mat.M41 - mat.M11,
B = mat.M42 - mat.M12,
C = mat.M43 - mat.M13,
D = mat.M44 - mat.M14
};
// bottom
var bottom = new PlaneF()
{
A = mat.M41 + mat.M21,
B = mat.M42 + mat.M22,
C = mat.M43 + mat.M23,
D = mat.M44 + mat.M24
};
// top
var top = new PlaneF()
{
A = mat.M41 - mat.M21,
B = mat.M42 - mat.M22,
C = mat.M43 - mat.M23,
D = mat.M44 - mat.M24
};
// near
var near = new PlaneF()
{
A = mat.M41 + mat.M31,
B = mat.M42 + mat.M32,
C = mat.M43 + mat.M33,
D = mat.M44 + mat.M34
};
// far
var far = new PlaneF()
{
A = mat.M41 - mat.M31,
B = mat.M42 - mat.M32,
C = mat.M43 - mat.M33,
D = mat.M44 - mat.M34
};
//Negate D because Fusee uses ax +by + cz = d
left.D *= -1;
right.D *= -1;
near.D *= -1;
far.D *= -1;
top.D *= -1;
bottom.D *= -1;
//Invert plane to get the normal to face outwards.
left *= -1;
right *= -1;
near *= -1;
far *= -1;
top *= -1;
bottom *= -1;
Left = left;
Right = right;
Top = top;
Bottom = bottom;
Near = near;
Far = far;
}
/// <summary>
/// Checks if a viewing frustum lies within or intersects this AABB.
/// </summary>
/// <param name="plane">The plane to test against.</param>
/// <returns>false if fully outside, true if inside or intersecting.</returns>
public bool InsideOrIntersectingPlane(PlaneF plane)
{
return(plane.InsideOrIntersecting(this));
}
