title: Three.js FXAA background transparency
body: <p>Created a simple scene with a cube in it.  Able to see the color of the containing element, (body), in the background.</p>
  
  <p>Added an FXAA shader and the antialiasing works well.  However the background is now black, so can no longer see the color of the background container.</p>
  
  <p>Added the following code:</p>
  
  <p>var target = new THREE.WebGLRenderTarget(512, 512);</p>
  
  <p>var composer = new THREE.EffectComposer( renderer, target );</p>
  
  <p>in order to set the effect composer render target format to THREE.RGBAFormat, rather than the default THREE.RGBFormat.</p>
  
  <p>This makes the background work properly, but then there are black and white edges around the cube and the antialiasing does not look very good.</p>
  
  <p>Repeated the above but used the Sepia shader instead of the FXAA shader.  This works correctly.  The cube looks sepia and the background containing element color is correct.</p>
  
  <p>Are there any workarounds to allow antialiasing and transparent background?</p>
  
  <p>Thanks for any help</p>