Do the wi-fi communications from Mac to Mac travel through the access point?
They go through the AP.

It's not like the MACs "see" each other just like that in the same network, it's the AP that "tells" them who's in the network. All data recieved and transmitted on a Wi-Fi network must pass through the router. The network is not triangular, all devices in a network except for the AP of course have only 1 connection ( MAC1---AP---MAC2 ).