My understanding is that the sentence `I will have played tennis.` is _future perfect_.

But, what happens if I substitute the word "will" with a modal such as "could" or "ought to"? Does that change the tense? If so, what tense is it?

For example, what tense is the sentence `I could have played tennis.`?

Does a similar mechanism come into play for the sentence `I will have been playing tennis.` (_future perfect continuous_) vs. `I could have been playing tennis.`?