title: Webgl Frustum view
body: <p>When I Render 5 boxes in webgl with 1 texture all of them, the app runs at 60 fps, nice. But when I render 70 boxes the performance dicrease to ~40fps but in the view volumes are still 5.</p>
  
  <p>I have debugged the app and all 70 boxes are using per fragment shaders when there are no need because 65 of them are out of frustum. I thought that gl.viewport declaration clipped out of view polygons but not.</p>
  
  <p>I would like to know if fustrum culling is the technique to avoid this? How can I activate fustrum culling? Is there any webgl command or I have to do it manually?</p>
  
  <p>Thanks in advance,</p>