Some creatures with extra ability are attached to their attack if they move a certain distance to their opponent before attacking. Take the example of the Gorgon, it has the ability to Tramble Charge:
Trampling load. If the gorgon moves straight at least 20 feet to a creature and then hits it with a bloody attack on the same turn, that target must make a Force 16 save or be knocked out. If the target is tilted, the gorgon can perform an attack with his hooves against it as a bonus action.
When it says 20 feet in a straight line to an opponent, how much should it be right? Should the last 20 feet of movement of the creature be in the same direction? Or is a movement model like East, Southeast, East or Southeast considered to have been moved directly from 20 feet to an opponent?