/// <summary>
/// Solve A * x = b, where b is a column vector. This is more efficient
/// than computing the inverse in one-shot cases.
/// </summary>
/// <param name="b">The b.</param>
/// <returns></returns>
public FVector3 Solve33(FVector3 b)
{
float det = FVector3.Dot(ex, FVector3.Cross(ey, ez));
if (det != 0.0f)
{
det = 1.0f / det;
}
return(new FVector3(det * FVector3.Dot(b, FVector3.Cross(ey, ez)),
det * FVector3.Dot(ex, FVector3.Cross(b, ez)),
det * FVector3.Dot(ex, FVector3.Cross(ey, b))));
}
public static void CreateLookAt(ref FVector3 cameraPosition, ref FVector3 cameraTarget, ref FVector3 cameraUpVector,
out FMatrix result)
{
// http://msdn.microsoft.com/en-us/library/bb205343(v=VS.85).aspx
FVector3 vz = FVector3.Normalize(cameraPosition - cameraTarget);
FVector3 vx = FVector3.Normalize(FVector3.Cross(cameraUpVector, vz));
FVector3 vy = FVector3.Cross(vz, vx);
result = Identity;
result.M11 = vx.X;
result.M12 = vy.X;
result.M13 = vz.X;
result.M21 = vx.Y;
result.M22 = vy.Y;
result.M23 = vz.Y;
result.M31 = vx.Z;
result.M32 = vy.Z;
result.M33 = vz.Z;
result.M41 = -FVector3.Dot(vx, cameraPosition);
result.M42 = -FVector3.Dot(vy, cameraPosition);
result.M43 = -FVector3.Dot(vz, cameraPosition);
}
