public Vector3 Sample(Triangle triangle, float u, float v)
 {
     Vector2 position = triangle.UVCoordinates(u, v);
     Color color = _bmp.GetPixel((int) (position.x * _bmp.Width + 0.5), (int) (position.y * _bmp.Height + 0.5));
     return Vector3.FromColor(color);
 }