Direct or naive realism certainly assumes in its principal versions that :
Perceptual states are belief states: To perceive an object is to acquire
a certain number of true beliefs about it that are causally received from the object
by using one's sense organs in a standard way. (M. S. Gram, 'Causation and Direct Realism', Philosophy of Science, Vol. 39, No. 3 (Sep., 1972), pp. 388-396 : 388.)
A more nuanced view can also be formulated :
(a) in normal cases of perception, physical or
material objects are, in a sense admittedly still in need of clarification,
directly or immediately perceived; and (b) that the justification for beliefs
about such objects that results from perception does not depend on ...
inference from the subjective character of perceptual experience ... but can be accounted for in some other way. (Laurence Bonjour, 'In Search of Direct Realism', Philosophy and Phenomenological Research, Vol. 69, No. 2 (Sep., 2004), pp. 349-367 : 351.)
By 'inference from the subjective character of perceptual experience' is meant inference from subjective sensory experience such as (if they exist) sense data or sensibilia.
A single objective reality
There is no valid inference from either characterisation of direct realism to a single objective reality of physical or material objects - or whatever else we might directly perceive. All that direct realism implies or presupposes is that we have some direct or immediate perception of the real, whatever the real might be. It is logically perfectly possible that the objects of our immediate or direct perception do not compose a single objective reality. It may be widely assumed by direct realists that they do and if direct realism is a correct theory of perception, they might be right. But this is an independent claim, not inherent in direct realism and not even guaranteed by its truth if it is true.