title: What exactly constitutes swizzling in OpenGL ES 2.0? (PowerVR SGX specifically.)
body: <p>PowerVR says  </p>
  
  <blockquote>
    <p>Swizzling the components of lowp vectors is expensive and should be
    avoided.</p>
  </blockquote>
  
  <p>What exactly is swizzling?  </p>
  
  <pre><code>color.brg  // This fits the definition I'm familiar with.
  </code></pre>
  
  <p>But what about <code>vec3(color.b, color.r, color.g)</code>, or <code>vec3(color)</code>, when <em>color</em> is a vec4?</p>
  
  <p>Does accessing or modifying a single component constitute a swizzle?  I really wouldn't think so, but if not, then you could work around swizzling by just doing a few more assignment operations manually.  I don't have a problem doing that, but it seems like magic to me, if you could get the same effect at a faster speed just by writing the code without swizzle notation.</p>