title: WebGL - reading pixel data from render buffer
body: <p>Is there a way to get the raw pixel data from a WebGL render buffer or frame buffer that is off screen?</p>
  
  <p>I'm using WebGL to do some image processing, e.g. blurring an image, adjusting color, etc. 
  I'm using frame buffers to render to textures at the full image size, then using that texture to display in the viewport at a smaller size. Can I get the pixel data of a buffer or texture so I can work with it in a normal canvas 2d context? Or am I stuck with changing the viewport to the full image size and grabbing the data with canvas.toDataURL()?</p>
  
  <p>Thanks.</p>