code: function (renderer) {
          // Remove status record on renderer
          renderer.__currentFrameBuffer = null;
  
          var _gl = renderer.gl;
  
          _gl.bindFramebuffer(GL_FRAMEBUFFER, null);
          this._boundRenderer = null;
  
          this._cache.use(renderer.__uid__);
          var viewport = this._cache.get('viewport');
          // Reset viewport;
          if (viewport) {
              renderer.setViewport(viewport);
          }
  
          this.updateMipmap(renderer);
      }
docs: Unbind the frame buffer after rendering
  @param  {clay.Renderer} renderer