We can infer a lot from the size and position of its eye sockets. The eyes were position so as to be forward facing, not side facing like an herbivores.

This article has a really good pocture in it showing you a direct view of the eye sockets from the snout. Its cheekbones and nostrils are designed so that it's visual field easily would clear them, giving it binocular vision like ours. The study that article discusses used fossils to model what dinosaur faces would have looked like, then examined their visual field. The trex had around a 55 degree binocular range, which is larger than many predatory birds that we know to have excellent vision over long distances. It's eyes were also gigantic, allowing for a lot of light to get in.

As for sense of smell, I don't know how we know about it; I think we assume it did because it's nostrils were also huge, and because most animals today have good senses of smell, meaning it's a good adaptation to have and likely would be present on the largest land predator to ever exist.