Let $x=1$, $y=0$, we get $f(0)=\frac{1}{2}$,

Let $x=n$, $y=1$, we have $f(n)=f(n+1)+f(n-1)$,

Similarly, $f(n+1)=f(n+2)+f(n)$,

Combining the above equations, we get $f(n+2)=-f(n-1)$,

Thus, $f(n)=-f(n+3)=f(n+6)$,

Therefore, the function is periodic with a period $T=6$,

So, $f(2012)=f(2)$,

Let $x=1$, $y=1$, we get $f(2)=-\frac{1}{4}$,

Hence, $\boxed{f(2012)=f(2)=-\frac{1}{4}}$,

The answer is $\boxed{-\frac{1}{4}}$;

Since the question asks for $f(2012)$, the term is relatively large, so we can immediately judge that the function must be a periodic function. Therefore, we should focus on finding the period; the method for finding the period can be either inductive or deductive reasoning.

Accurately finding the period is the key to this type of problem (where the term is quite large). Both induction and deduction methods can be used to find the period. Choose the method you are most comfortable with during problem-solving.