function accumulate(id) {
        if (!self._accumulatingId || id !== self._accumulatingId) {
            return;
        }

        var isFinished = true;
        for (var i = 0; i < self.views.length; i++) {
            isFinished = self.views[i].isAccumulateFinished() && needsAccumulate;
        }

        if (!isFinished) {
            self._doRender(true);

            if (immediate) {
                accumulate(id);
            }
            else {
                animation_requestAnimationFrame(function () {
                    accumulate(id);
                });
            }
        }
    }
Start accumulating all the views.
Accumulating is for antialising and have more sampling in SSAO
@private