I'm not sure what you mean: what you give
is a "continuous-time function"- or at least a continuous function of t.
If you want to you can replace each of

,

, and W with their explicit dependence on t:

(I've changed the dummy variable in the integral to u so as not to confuse it with the variable t.)
But I don't think that really adds anything as long as you don't know the explicit form of f.