docs: public GrayF32 render()
  	{
  		ImageMiscOps.fill(output,background);
  		ImageMiscOps.fill(depthMap,Float.MAX_VALUE);
  
  		for (int i = 0; i < scene.size(); i++) {
  			SurfaceRect r = scene.get(i);
  			r.rectInCamera();
  		}
  
  		if( BoofConcurrency.USE_CONCURRENT ) {
  			renderMultiThread();
  		} else {
  			renderSingleThread();
  		}
  
  		return getOutput();
  	}