title: Opengl low FPS when looking certain direction
body: <p>I'm drawing surface composed of thousands of cubes. However when I'm looking in positive Z direction - that's where the light is, I get low fps and artifacts. 
  This is how it looks when I'm looking in negative Z direction: 
  <img src="https://i.imgur.com/x91waR3.png" alt="1">
  This is how it looks when I'm looking in positive Z direction, also drops fps noticeably:
  <img src="https://i.imgur.com/rYwtocc.png" alt="1"></p>