private void ReadVertexNormal()
{
var parts = SplitLine();
if (parts.Length != 4)
{
ThrowInvalidModelFormatException("Wrong vertex normal format");
}
if (!TryStrictDoubleParse(parts[1], out var x))
{
ThrowParseException("vertex normal X");
}
if (!TryStrictDoubleParse(parts[2], out var y))
{
ThrowParseException("vertex normal Y");
}
if (!TryStrictDoubleParse(parts[3], out var z))
{
ThrowParseException("vertex normal Z");
}
_model.AddVertexNormal(new Vector(x, y, z));
}
