polyfill = function polyfill(object, method) {
	  var showWarn = arguments.length > 2 && arguments[2] !== undefined ? arguments[2] : true;
	  if (object[method]) return;
	  if (showWarn) console.warn("@PostProcessorModule: pass.".concat(method, "() was not found."), object);

	  object[method] = function () {};
	}
The input and output buffers share a single depth texture. Depth will be
written to this texture when something is rendered into one of the buffers
and the involved materials have depth write enabled.

You may enable this mechanism during the instantiation of the composer or
by assigning a DepthTexture instance later on. You may also disable it by
assigning null.

@type {DepthTexture}