message: cleanup colorGradingAsSubpass shader
  It was confusing how it reused the input as a temporary variable.
diff: @@ -36,7 +36,7 @@ material {
  ],
  outputs : [
  {
  - name : color,
  + name : dummy,
  target : color,
  type : float4,
  location : 0
  @@ -111,16 +111,16 @@ fragment {
  }
  void postProcess(inout PostProcessInputs postProcess) {
  - postProcess.color = resolve();
  + vec4 color = resolve();
  if (materialParams.dithering > 0) {
  - vec4 dithered = dither(postProcess.color, materialParams.temporalNoise);
  + vec4 dithered = dither(color, materialParams.temporalNoise);
  #if POST_PROCESS_OPAQUE
  - postProcess.color.rgb = dithered.rgb;
  + color.rgb = dithered.rgb;
  #else
  - postProcess.color = dithered;
  + color = dithered;
  #endif
  }
  - postProcess.tonemappedOutput = postProcess.color;
  + postProcess.tonemappedOutput = color;
  }
  }
  