/// <summary>
/// Fills the matrix with rows <paramref name="i"/>, <paramref name="j"/>, <paramref name="k"/>, <paramref name="l"/>.
/// </summary>
public Mat4(Vec4 i, Vec4 j, Vec4 k, Vec4 l)
{
Values = new float[16];
for (int m = 0; m < 4; m++)
{
this[m, 0] = i[m];
this[m, 1] = j[m];
this[m, 2] = k[m];
this[m, 3] = l[m];
}
}
/// <summary>
/// There is no any normalization.
/// </summary>
public Quat ToQuat()
{
var trace = this[0, 0] + this[1, 1] + this[2, 2];
Vec4 result = new Vec4();
if (trace > 0)
{
var s = (trace + 1).Sqrt() * 2;
var invS = 1f / s;
result.W = s * 0.25f;
result.X = (this[2, 1] - this[1, 2]) * invS;
result.Y = (this[0, 2] - this[2, 0]) * invS;
result.Z = (this[1, 0] - this[0, 1]) * invS;
}
else
{
float m00 = this[0, 0], m11 = this[1, 1], m22 = this[2, 2];
if (m00 > m11 && m00 > m22)
{
var s = (1 + m00 - m11 - m22).Sqrt() * 2;
var invS = 1f / s;
result.W = (this[2, 1] - this[1, 2]) * invS;
result.X = s * 0.25f;
result.Y = (this[0, 1] + this[1, 0]) * invS;
result.Z = (this[0, 2] + this[2, 0]) * invS;
}
else if (m11 > m22)
{
var s = (1 + m11 - m00 - m22).Sqrt() * 2;
var invS = 1f / s;
result.W = (this[0, 2] - this[2, 0]) * invS;
result.X = (this[0, 1] + this[1, 0]) * invS;
result.Y = s * 0.25f;
result.Z = (this[1, 2] + this[2, 1]) * invS;
}
else
{
var s = (1 + m22 - m00 - m11).Sqrt() * 2;
var invS = 1f / s;
result.W = (this[1, 0] - this[0, 1]) * invS;
result.X = (this[0, 2] + this[2, 0]) * invS;
result.Y = (this[1, 2] + this[2, 1]) * invS;
result.Z = s * 0.25f;
}
}
return(new Quat(result));
}
public static Vec4 operator *(Vec4 a, Mat4 b)
{
Vec4 temp = Vec4.Zero;
for (int j = 0; j < 4; j++)
{
temp[j] = a[0] * b[0, j] +
a[1] * b[1, j] +
a[2] * b[2, j] +
a[3] * b[3, j];
}
return(temp);
}
public bool Equals(Vec4 other)
{
return(this == other);
}
public static float Dot(Vec4 a, Vec4 b)
{
return(a.X * b.X + a.Y * b.Y + a.Z * b.Z + a.W * b.W);
}
public float Dot(Vec4 a)
{
return(Dot(this, a));
}
